1 | /* |
2 | * Copyright (c) 2000-2022 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. The rights granted to you under the License |
10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | */ |
28 | /* |
29 | * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 |
30 | * The Regents of the University of California. All rights reserved. |
31 | * |
32 | * Redistribution and use in source and binary forms, with or without |
33 | * modification, are permitted provided that the following conditions |
34 | * are met: |
35 | * 1. Redistributions of source code must retain the above copyright |
36 | * notice, this list of conditions and the following disclaimer. |
37 | * 2. Redistributions in binary form must reproduce the above copyright |
38 | * notice, this list of conditions and the following disclaimer in the |
39 | * documentation and/or other materials provided with the distribution. |
40 | * 3. All advertising materials mentioning features or use of this software |
41 | * must display the following acknowledgement: |
42 | * This product includes software developed by the University of |
43 | * California, Berkeley and its contributors. |
44 | * 4. Neither the name of the University nor the names of its contributors |
45 | * may be used to endorse or promote products derived from this software |
46 | * without specific prior written permission. |
47 | * |
48 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
49 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
50 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
51 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
52 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
53 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
54 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
55 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
56 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
57 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
58 | * SUCH DAMAGE. |
59 | * |
60 | * @(#)tcp_output.c 8.4 (Berkeley) 5/24/95 |
61 | * $FreeBSD: src/sys/netinet/tcp_output.c,v 1.39.2.10 2001/07/07 04:30:38 silby Exp $ |
62 | */ |
63 | /* |
64 | * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce |
65 | * support for mandatory and extensible security protections. This notice |
66 | * is included in support of clause 2.2 (b) of the Apple Public License, |
67 | * Version 2.0. |
68 | */ |
69 | |
70 | #define _IP_VHL |
71 | |
72 | #include "tcp_includes.h" |
73 | |
74 | #include <sys/param.h> |
75 | #include <sys/systm.h> |
76 | #include <sys/kernel.h> |
77 | #include <sys/sysctl.h> |
78 | #include <sys/mbuf.h> |
79 | #include <sys/domain.h> |
80 | #include <sys/protosw.h> |
81 | #include <sys/socket.h> |
82 | #include <sys/socketvar.h> |
83 | |
84 | #include <net/route.h> |
85 | #include <net/ntstat.h> |
86 | #include <net/if_var.h> |
87 | #include <net/if.h> |
88 | #include <net/if_types.h> |
89 | #include <net/dlil.h> |
90 | |
91 | #include <netinet/in.h> |
92 | #include <netinet/in_systm.h> |
93 | #include <netinet/in_var.h> |
94 | #include <netinet/in_tclass.h> |
95 | #include <netinet/ip.h> |
96 | #include <netinet/in_pcb.h> |
97 | #include <netinet/ip_var.h> |
98 | #include <mach/sdt.h> |
99 | #include <netinet6/in6_pcb.h> |
100 | #include <netinet/ip6.h> |
101 | #include <netinet6/ip6_var.h> |
102 | #include <netinet/tcp.h> |
103 | #include <netinet/tcp_cache.h> |
104 | #include <netinet/tcp_fsm.h> |
105 | #include <netinet/tcp_seq.h> |
106 | #include <netinet/tcp_timer.h> |
107 | #include <netinet/tcp_var.h> |
108 | #include <netinet/tcpip.h> |
109 | #include <netinet/tcp_cc.h> |
110 | #if TCPDEBUG |
111 | #include <netinet/tcp_debug.h> |
112 | #endif |
113 | #include <netinet/tcp_log.h> |
114 | #include <sys/kdebug.h> |
115 | #include <mach/sdt.h> |
116 | |
117 | #if IPSEC |
118 | #include <netinet6/ipsec.h> |
119 | #endif /*IPSEC*/ |
120 | |
121 | #if MPTCP |
122 | #include <netinet/mptcp_var.h> |
123 | #include <netinet/mptcp.h> |
124 | #include <netinet/mptcp_opt.h> |
125 | #include <netinet/mptcp_seq.h> |
126 | #endif |
127 | |
128 | #include <corecrypto/ccaes.h> |
129 | |
130 | #define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 1) |
131 | #define DBG_LAYER_END NETDBG_CODE(DBG_NETTCP, 3) |
132 | #define DBG_FNC_TCP_OUTPUT NETDBG_CODE(DBG_NETTCP, (4 << 8) | 1) |
133 | |
134 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, path_mtu_discovery, |
135 | CTLFLAG_RW | CTLFLAG_LOCKED, int, path_mtu_discovery, 1, |
136 | "Enable Path MTU Discovery" ); |
137 | |
138 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, local_slowstart_flightsize, |
139 | CTLFLAG_RW | CTLFLAG_LOCKED, int, ss_fltsz_local, 8, |
140 | "Slow start flight size for local networks" ); |
141 | |
142 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, tso, CTLFLAG_RW | CTLFLAG_LOCKED, |
143 | int, tcp_do_tso, 1, "Enable TCP Segmentation Offload" ); |
144 | |
145 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, ecn_setup_percentage, |
146 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ecn_setup_percentage, 100, |
147 | "Max ECN setup percentage" ); |
148 | |
149 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, accurate_ecn, |
150 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_ecn, 0, |
151 | "Accurate ECN mode (0: disable, 1: enable ACE feedback" ); |
152 | |
153 | // TO BE REMOVED |
154 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, do_ack_compression, |
155 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_ack_compression, 1, |
156 | "Enable TCP ACK compression (on (cell only): 1, off: 0, on (all interfaces): 2)" ); |
157 | |
158 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, ack_compression_rate, |
159 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_ack_compression_rate, TCP_COMP_CHANGE_RATE, |
160 | "Rate at which we force sending new ACKs (in ms)" ); |
161 | |
162 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, randomize_timestamps, |
163 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_randomize_timestamps, 1, |
164 | "Randomize TCP timestamps to prevent tracking (on: 1, off: 0)" ); |
165 | |
166 | static int |
167 | sysctl_change_ecn_setting SYSCTL_HANDLER_ARGS |
168 | { |
169 | #pragma unused(oidp, arg1, arg2) |
170 | int i, err = 0, changed = 0; |
171 | struct ifnet *ifp; |
172 | |
173 | err = sysctl_io_number(req, bigValue: tcp_ecn_outbound, valueSize: sizeof(int32_t), |
174 | pValue: &i, changed: &changed); |
175 | if (err != 0 || req->newptr == USER_ADDR_NULL) { |
176 | return err; |
177 | } |
178 | |
179 | if (changed) { |
180 | if ((tcp_ecn_outbound == 0 || tcp_ecn_outbound == 1) && |
181 | (i == 0 || i == 1)) { |
182 | tcp_ecn_outbound = i; |
183 | SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound); |
184 | return err; |
185 | } |
186 | if (tcp_ecn_outbound == 2 && (i == 0 || i == 1)) { |
187 | /* |
188 | * Reset ECN enable flags on non-cellular |
189 | * interfaces so that the system default will take |
190 | * over |
191 | */ |
192 | ifnet_head_lock_shared(); |
193 | TAILQ_FOREACH(ifp, &ifnet_head, if_link) { |
194 | if (!IFNET_IS_CELLULAR(ifp)) { |
195 | if_clear_eflags(ifp, |
196 | IFEF_ECN_ENABLE | |
197 | IFEF_ECN_DISABLE); |
198 | } |
199 | } |
200 | ifnet_head_done(); |
201 | } else { |
202 | /* |
203 | * Set ECN enable flags on non-cellular |
204 | * interfaces |
205 | */ |
206 | ifnet_head_lock_shared(); |
207 | TAILQ_FOREACH(ifp, &ifnet_head, if_link) { |
208 | if (!IFNET_IS_CELLULAR(ifp)) { |
209 | if_set_eflags(ifp, IFEF_ECN_ENABLE); |
210 | if_clear_eflags(ifp, IFEF_ECN_DISABLE); |
211 | } |
212 | } |
213 | ifnet_head_done(); |
214 | } |
215 | tcp_ecn_outbound = i; |
216 | SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_initiate_out, tcp_ecn_outbound); |
217 | } |
218 | /* Change the other one too as the work is done */ |
219 | if (i == 2 || tcp_ecn_inbound == 2) { |
220 | tcp_ecn_inbound = i; |
221 | SYSCTL_SKMEM_UPDATE_FIELD(tcp.ecn_negotiate_in, tcp_ecn_inbound); |
222 | } |
223 | return err; |
224 | } |
225 | |
226 | int tcp_ecn_outbound = 2; |
227 | SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_initiate_out, |
228 | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_outbound, 0, |
229 | sysctl_change_ecn_setting, "IU" , |
230 | "Initiate ECN for outbound connections" ); |
231 | |
232 | int tcp_ecn_inbound = 2; |
233 | SYSCTL_PROC(_net_inet_tcp, OID_AUTO, ecn_negotiate_in, |
234 | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_ecn_inbound, 0, |
235 | sysctl_change_ecn_setting, "IU" , |
236 | "Initiate ECN for inbound connections" ); |
237 | |
238 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, packetchain, |
239 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_packet_chaining, 50, |
240 | "Enable TCP output packet chaining" ); |
241 | |
242 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, socket_unlocked_on_output, |
243 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_output_unlocked, 1, |
244 | "Unlock TCP when sending packets down to IP" ); |
245 | |
246 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, min_iaj_win, |
247 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_min_iaj_win, MIN_IAJ_WIN, |
248 | "Minimum recv win based on inter-packet arrival jitter" ); |
249 | |
250 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, acc_iaj_react_limit, |
251 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_acc_iaj_react_limit, |
252 | ACC_IAJ_REACT_LIMIT, "Accumulated IAJ when receiver starts to react" ); |
253 | |
254 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufinc, |
255 | CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_autosndbuf_inc, |
256 | 8 * 1024, "Increment in send socket bufffer size" ); |
257 | |
258 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, autosndbufmax, |
259 | CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_KERN, uint32_t, tcp_autosndbuf_max, 2 * 1024 * 1024, |
260 | "Maximum send socket buffer size" ); |
261 | |
262 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, rtt_recvbg, |
263 | CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_use_rtt_recvbg, 1, |
264 | "Use RTT for bg recv algorithm" ); |
265 | |
266 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_throttle_minwin, |
267 | CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_recv_throttle_minwin, 16 * 1024, |
268 | "Minimum recv win for throttling" ); |
269 | |
270 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, enable_tlp, |
271 | CTLFLAG_RW | CTLFLAG_LOCKED, |
272 | int32_t, tcp_enable_tlp, 1, "Enable Tail loss probe" ); |
273 | |
274 | static int32_t packchain_newlist = 0; |
275 | static int32_t packchain_looped = 0; |
276 | static int32_t packchain_sent = 0; |
277 | |
278 | /* temporary: for testing */ |
279 | #if IPSEC |
280 | extern int ipsec_bypass; |
281 | #endif |
282 | |
283 | extern int slowlink_wsize; /* window correction for slow links */ |
284 | |
285 | extern u_int32_t kipf_count; |
286 | |
287 | static int tcp_ip_output(struct socket *, struct tcpcb *, struct mbuf *, |
288 | int, struct mbuf *, int, int, boolean_t); |
289 | static int tcp_recv_throttle(struct tcpcb *tp); |
290 | |
291 | __attribute__((noinline)) |
292 | static int32_t |
293 | tcp_tfo_check(struct tcpcb *tp, int32_t len) |
294 | { |
295 | struct socket *so = tp->t_inpcb->inp_socket; |
296 | unsigned int optlen = 0; |
297 | unsigned int cookie_len; |
298 | |
299 | if (tp->t_flags & TF_NOOPT) { |
300 | goto fallback; |
301 | } |
302 | |
303 | if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) && |
304 | !tcp_heuristic_do_tfo(tp)) { |
305 | tp->t_tfo_stats |= TFO_S_HEURISTICS_DISABLE; |
306 | tcpstat.tcps_tfo_heuristics_disable++; |
307 | goto fallback; |
308 | } |
309 | |
310 | if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) { |
311 | return len; |
312 | } |
313 | |
314 | optlen += TCPOLEN_MAXSEG; |
315 | |
316 | if (tp->t_flags & TF_REQ_SCALE) { |
317 | optlen += 4; |
318 | } |
319 | |
320 | #if MPTCP |
321 | if ((so->so_flags & SOF_MP_SUBFLOW) && mptcp_enable && |
322 | (tp->t_rxtshift <= mptcp_mpcap_retries || |
323 | (tptomptp(tp)->mpt_mpte->mpte_flags & MPTE_FORCE_ENABLE))) { |
324 | optlen += sizeof(struct mptcp_mpcapable_opt_common) + sizeof(mptcp_key_t); |
325 | } |
326 | #endif /* MPTCP */ |
327 | |
328 | if (tp->t_flags & TF_REQ_TSTMP) { |
329 | optlen += TCPOLEN_TSTAMP_APPA; |
330 | } |
331 | |
332 | if (SACK_ENABLED(tp)) { |
333 | optlen += TCPOLEN_SACK_PERMITTED; |
334 | } |
335 | |
336 | /* Now, decide whether to use TFO or not */ |
337 | |
338 | /* Don't even bother trying if there is no space at all... */ |
339 | if (MAX_TCPOPTLEN - optlen < TCPOLEN_FASTOPEN_REQ) { |
340 | goto fallback; |
341 | } |
342 | |
343 | cookie_len = tcp_cache_get_cookie_len(tp); |
344 | if (cookie_len == 0) { |
345 | /* No cookie, so we request one */ |
346 | return 0; |
347 | } |
348 | |
349 | /* There is not enough space for the cookie, so we cannot do TFO */ |
350 | if (MAX_TCPOPTLEN - optlen < cookie_len) { |
351 | goto fallback; |
352 | } |
353 | |
354 | /* Do not send SYN+data if there is more in the queue than MSS */ |
355 | if (so->so_snd.sb_cc > (tp->t_maxopd - MAX_TCPOPTLEN)) { |
356 | goto fallback; |
357 | } |
358 | |
359 | /* Ok, everything looks good. We can go on and do TFO */ |
360 | return len; |
361 | |
362 | fallback: |
363 | tcp_disable_tfo(tp); |
364 | return 0; |
365 | } |
366 | |
367 | /* Returns the number of bytes written to the TCP option-space */ |
368 | __attribute__((noinline)) |
369 | static unsigned int |
370 | tcp_tfo_write_cookie_rep(struct tcpcb *tp, unsigned int optlen, u_char *opt) |
371 | { |
372 | u_char out[CCAES_BLOCK_SIZE]; |
373 | unsigned ret = 0; |
374 | u_char *bp; |
375 | |
376 | if (MAX_TCPOPTLEN - optlen < |
377 | TCPOLEN_FASTOPEN_REQ + TFO_COOKIE_LEN_DEFAULT) { |
378 | return ret; |
379 | } |
380 | |
381 | tcp_tfo_gen_cookie(inp: tp->t_inpcb, out, blk_size: sizeof(out)); |
382 | |
383 | bp = opt + optlen; |
384 | |
385 | *bp++ = TCPOPT_FASTOPEN; |
386 | *bp++ = 2 + TFO_COOKIE_LEN_DEFAULT; |
387 | memcpy(dst: bp, src: out, TFO_COOKIE_LEN_DEFAULT); |
388 | ret += 2 + TFO_COOKIE_LEN_DEFAULT; |
389 | |
390 | tp->t_tfo_stats |= TFO_S_COOKIE_SENT; |
391 | tcpstat.tcps_tfo_cookie_sent++; |
392 | |
393 | return ret; |
394 | } |
395 | |
396 | __attribute__((noinline)) |
397 | static unsigned int |
398 | tcp_tfo_write_cookie(struct tcpcb *tp, unsigned int optlen, int32_t len, |
399 | u_char *opt) |
400 | { |
401 | uint8_t tfo_len; |
402 | struct socket *so = tp->t_inpcb->inp_socket; |
403 | unsigned ret = 0; |
404 | int res; |
405 | u_char *bp; |
406 | |
407 | if (TCPOLEN_FASTOPEN_REQ > MAX_TCPOPTLEN - optlen) { |
408 | return 0; |
409 | } |
410 | tfo_len = (uint8_t)(MAX_TCPOPTLEN - optlen - TCPOLEN_FASTOPEN_REQ); |
411 | |
412 | if (so->so_flags1 & SOF1_DATA_AUTHENTICATED) { |
413 | /* If there is some data, let's track it */ |
414 | if (len > 0) { |
415 | tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT; |
416 | tcpstat.tcps_tfo_syn_data_sent++; |
417 | } |
418 | |
419 | return 0; |
420 | } |
421 | |
422 | bp = opt + optlen; |
423 | |
424 | /* |
425 | * The cookie will be copied in the appropriate place within the |
426 | * TCP-option space. That way we avoid the need for an intermediate |
427 | * variable. |
428 | */ |
429 | res = tcp_cache_get_cookie(tp, cookie: bp + TCPOLEN_FASTOPEN_REQ, len: &tfo_len); |
430 | if (res == 0) { |
431 | *bp++ = TCPOPT_FASTOPEN; |
432 | *bp++ = TCPOLEN_FASTOPEN_REQ; |
433 | ret += TCPOLEN_FASTOPEN_REQ; |
434 | |
435 | tp->t_tfo_flags |= TFO_F_COOKIE_REQ; |
436 | |
437 | tp->t_tfo_stats |= TFO_S_COOKIE_REQ; |
438 | tcpstat.tcps_tfo_cookie_req++; |
439 | } else { |
440 | *bp++ = TCPOPT_FASTOPEN; |
441 | *bp++ = TCPOLEN_FASTOPEN_REQ + tfo_len; |
442 | |
443 | ret += TCPOLEN_FASTOPEN_REQ + tfo_len; |
444 | |
445 | tp->t_tfo_flags |= TFO_F_COOKIE_SENT; |
446 | |
447 | /* If there is some data, let's track it */ |
448 | if (len > 0) { |
449 | tp->t_tfo_stats |= TFO_S_SYN_DATA_SENT; |
450 | tcpstat.tcps_tfo_syn_data_sent++; |
451 | } |
452 | } |
453 | |
454 | return ret; |
455 | } |
456 | |
457 | static inline bool |
458 | tcp_send_ecn_flags_on_syn(struct tcpcb *tp) |
459 | { |
460 | /* We allow Accurate ECN negotiation on first retransmission as well */ |
461 | bool send_on_first_retrans = (tp->ecn_flags & TE_ACE_SETUPSENT) && |
462 | (tp->t_rxtshift <= 1); |
463 | |
464 | return !(tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) || send_on_first_retrans; |
465 | } |
466 | |
467 | void |
468 | tcp_set_ecn(struct tcpcb *tp, struct ifnet *ifp) |
469 | { |
470 | boolean_t inbound; |
471 | |
472 | /* |
473 | * Socket option has precedence |
474 | */ |
475 | if (tp->ecn_flags & TE_ECN_MODE_ENABLE) { |
476 | tp->ecn_flags |= TE_ENABLE_ECN; |
477 | goto check_heuristic; |
478 | } |
479 | |
480 | if (tp->ecn_flags & TE_ECN_MODE_DISABLE) { |
481 | tp->ecn_flags &= ~TE_ENABLE_ECN; |
482 | return; |
483 | } |
484 | /* |
485 | * Per interface setting comes next |
486 | */ |
487 | if (ifp != NULL) { |
488 | if (ifp->if_eflags & IFEF_ECN_ENABLE) { |
489 | tp->ecn_flags |= TE_ENABLE_ECN; |
490 | goto check_heuristic; |
491 | } |
492 | |
493 | if (ifp->if_eflags & IFEF_ECN_DISABLE) { |
494 | tp->ecn_flags &= ~TE_ENABLE_ECN; |
495 | return; |
496 | } |
497 | } |
498 | /* |
499 | * System wide settings come last |
500 | */ |
501 | inbound = (tp->t_inpcb->inp_socket->so_head != NULL); |
502 | if ((inbound && tcp_ecn_inbound == 1) || |
503 | (!inbound && tcp_ecn_outbound == 1)) { |
504 | tp->ecn_flags |= TE_ENABLE_ECN; |
505 | goto check_heuristic; |
506 | } else { |
507 | tp->ecn_flags &= ~TE_ENABLE_ECN; |
508 | } |
509 | |
510 | return; |
511 | |
512 | check_heuristic: |
513 | if (TCP_ACC_ECN_ENABLED(tp)) { |
514 | /* Allow ECN when Accurate ECN is enabled until heuristics are fixed */ |
515 | tp->ecn_flags |= TE_ENABLE_ECN; |
516 | /* Set the accurate ECN state */ |
517 | if (tp->t_client_accecn_state == tcp_connection_client_accurate_ecn_feature_disabled) { |
518 | tp->t_client_accecn_state = tcp_connection_client_accurate_ecn_feature_enabled; |
519 | } |
520 | if (tp->t_server_accecn_state == tcp_connection_server_accurate_ecn_feature_disabled) { |
521 | tp->t_server_accecn_state = tcp_connection_server_accurate_ecn_feature_enabled; |
522 | } |
523 | } |
524 | if (!tcp_heuristic_do_ecn(tp) && !TCP_ACC_ECN_ENABLED(tp)) { |
525 | /* Allow ECN when Accurate ECN is enabled until heuristics are fixed */ |
526 | tp->ecn_flags &= ~TE_ENABLE_ECN; |
527 | } |
528 | /* |
529 | * If the interface setting, system-level setting and heuristics |
530 | * allow to enable ECN, randomly select 5% of connections to |
531 | * enable it |
532 | */ |
533 | if ((tp->ecn_flags & (TE_ECN_MODE_ENABLE | TE_ECN_MODE_DISABLE |
534 | | TE_ENABLE_ECN)) == TE_ENABLE_ECN) { |
535 | /* |
536 | * Use the random value in iss for randomizing |
537 | * this selection |
538 | */ |
539 | if ((tp->iss % 100) >= tcp_ecn_setup_percentage && !TCP_ACC_ECN_ENABLED(tp)) { |
540 | /* Don't disable Accurate ECN randomly */ |
541 | tp->ecn_flags &= ~TE_ENABLE_ECN; |
542 | } |
543 | } |
544 | } |
545 | |
546 | int |
547 | tcp_flight_size(struct tcpcb *tp) |
548 | { |
549 | int ret; |
550 | |
551 | VERIFY(tp->sackhint.sack_bytes_acked >= 0); |
552 | VERIFY(tp->sackhint.sack_bytes_rexmit >= 0); |
553 | |
554 | /* |
555 | * RFC6675, SetPipe (), SACK'd bytes are discounted. All the rest is still in-flight. |
556 | */ |
557 | ret = tp->snd_nxt - tp->snd_una - tp->sackhint.sack_bytes_acked; |
558 | |
559 | if (ret < 0) { |
560 | /* |
561 | * This happens when the RTO-timer fires because snd_nxt gets artificially |
562 | * decreased. If we then receive some SACK-blogs, sack_bytes_acked is |
563 | * going to be high. |
564 | */ |
565 | ret = 0; |
566 | } |
567 | |
568 | return ret; |
569 | } |
570 | |
571 | /* |
572 | * Either of ECT0 or ECT1 flag should be set |
573 | * when this function is called |
574 | */ |
575 | static void |
576 | tcp_add_accecn_option(struct tcpcb *tp, uint16_t flags, uint32_t *lp, uint8_t *optlen) |
577 | { |
578 | uint8_t max_len = TCP_MAXOLEN - *optlen; |
579 | uint8_t len = TCPOLEN_ACCECN_EMPTY; |
580 | |
581 | uint32_t e1b = (uint32_t)(tp->t_rcv_ect1_bytes & TCP_ACO_MASK); |
582 | uint32_t e0b = (uint32_t)(tp->t_rcv_ect0_bytes & TCP_ACO_MASK); |
583 | uint32_t ceb = (uint32_t)(tp->t_rcv_ce_bytes & TCP_ACO_MASK); |
584 | |
585 | if (max_len < TCPOLEN_ACCECN_EMPTY) { |
586 | TCP_LOG(tp, "not enough space to add any AccECN option" ); |
587 | return; |
588 | } |
589 | |
590 | if (!(flags & TH_SYN || (tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) || |
591 | tp->snd_una == tp->iss + 1 || |
592 | tp->ecn_flags & (TE_ACO_ECT1 | TE_ACO_ECT0))) { |
593 | /* |
594 | * Since this is neither a SYN-ACK packet, nor the final ACK of |
595 | * the 3WHS (nor the first acked data segment) nor any of the ECT byte |
596 | * counter flags are set, no need to send the option. |
597 | */ |
598 | return; |
599 | } |
600 | |
601 | if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) && |
602 | tp->t_rxtshift >= 1) { |
603 | /* |
604 | * If this is a SYN-ACK retransmission (first), |
605 | * retry without AccECN option and just with ACE fields. |
606 | * From second retransmission onwards, we don't send any |
607 | * Accurate ECN state. |
608 | */ |
609 | return; |
610 | } |
611 | |
612 | if (max_len < (TCPOLEN_ACCECN_EMPTY + 1 * TCPOLEN_ACCECN_COUNTER)) { |
613 | /* Can carry EMPTY option which can be used to test path in SYN-ACK packet */ |
614 | if (flags & TH_SYN) { |
615 | *lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | |
616 | (TCPOPT_NOP << 8) | TCPOPT_NOP); |
617 | *optlen += len + 2; /* 2 NOPs */ |
618 | TCP_LOG(tp, "add empty AccECN option, optlen=%u" , *optlen); |
619 | } |
620 | } else if (max_len < (TCPOLEN_ACCECN_EMPTY + 2 * TCPOLEN_ACCECN_COUNTER)) { |
621 | /* Can carry one option */ |
622 | len += 1 * TCPOLEN_ACCECN_COUNTER; |
623 | if (tp->ecn_flags & TE_ACO_ECT1) { |
624 | *lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff)); |
625 | *lp++ = htonl(((e1b & 0xff) << 24) | (TCPOPT_NOP << 16) | (TCPOPT_NOP << 8) | TCPOPT_NOP); |
626 | } else { |
627 | *lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff)); |
628 | *lp++ = htonl(((e0b & 0xff) << 24) | (TCPOPT_NOP << 16) | (TCPOPT_NOP << 8) | TCPOPT_NOP); |
629 | } |
630 | *optlen += len + 3; /* 3 NOPs */ |
631 | TCP_LOG(tp, "add single counter for AccECN option, optlen=%u" , *optlen); |
632 | } else if (max_len < (TCPOLEN_ACCECN_EMPTY + 3 * TCPOLEN_ACCECN_COUNTER)) { |
633 | /* Can carry two options */ |
634 | len += 2 * TCPOLEN_ACCECN_COUNTER; |
635 | if (tp->ecn_flags & TE_ACO_ECT1) { |
636 | *lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff)); |
637 | *lp++ = htonl(((e1b & 0xff) << 24) | (ceb & 0xffffff)); |
638 | } else { |
639 | *lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff)); |
640 | *lp++ = htonl(((e0b & 0xff) << 24) | (ceb & 0xffffff)); |
641 | } |
642 | *optlen += len; /* 0 NOPs */ |
643 | TCP_LOG(tp, "add 2 counters for AccECN option, optlen=%u" , *optlen); |
644 | } else { |
645 | /* |
646 | * TCP option sufficient to hold full AccECN option |
647 | * but send counter that changed during the entire connection. |
648 | */ |
649 | len += 3 * TCPOLEN_ACCECN_COUNTER; |
650 | /* Can carry all three options */ |
651 | if (tp->ecn_flags & TE_ACO_ECT1) { |
652 | *lp++ = htonl((TCPOPT_ACCECN1 << 24) | (len << 16) | ((e1b >> 8) & 0xffff)); |
653 | *lp++ = htonl(((e1b & 0xff) << 24) | (ceb & 0xffffff)); |
654 | *lp++ = htonl(((e0b & 0xffffff) << 8) | TCPOPT_NOP); |
655 | } else { |
656 | *lp++ = htonl((TCPOPT_ACCECN0 << 24) | (len << 16) | ((e0b >> 8) & 0xffff)); |
657 | *lp++ = htonl(((e0b & 0xff) << 24) | (ceb & 0xffffff)); |
658 | *lp++ = htonl(((e1b & 0xffffff) << 8) | TCPOPT_NOP); |
659 | } |
660 | *optlen += len + 1; /* 1 NOP */ |
661 | TCP_LOG(tp, "add all 3 counters for AccECN option, optlen=%u" , *optlen); |
662 | } |
663 | } |
664 | |
665 | /* |
666 | * Tcp output routine: figure out what should be sent and send it. |
667 | * |
668 | * Returns: 0 Success |
669 | * EADDRNOTAVAIL |
670 | * ENOBUFS |
671 | * EMSGSIZE |
672 | * EHOSTUNREACH |
673 | * ENETDOWN |
674 | * ip_output_list:ENOMEM |
675 | * ip_output_list:EADDRNOTAVAIL |
676 | * ip_output_list:ENETUNREACH |
677 | * ip_output_list:EHOSTUNREACH |
678 | * ip_output_list:EACCES |
679 | * ip_output_list:EMSGSIZE |
680 | * ip_output_list:ENOBUFS |
681 | * ip_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL] |
682 | * ip6_output_list:EINVAL |
683 | * ip6_output_list:EOPNOTSUPP |
684 | * ip6_output_list:EHOSTUNREACH |
685 | * ip6_output_list:EADDRNOTAVAIL |
686 | * ip6_output_list:ENETUNREACH |
687 | * ip6_output_list:EMSGSIZE |
688 | * ip6_output_list:ENOBUFS |
689 | * ip6_output_list:??? [ignorable: mostly IPSEC/firewall/DLIL] |
690 | */ |
691 | int |
692 | tcp_output(struct tcpcb *tp) |
693 | { |
694 | struct inpcb *inp = tp->t_inpcb; |
695 | struct socket *so = inp->inp_socket; |
696 | int32_t len, recwin, sendwin, off; |
697 | uint32_t max_len = 0; |
698 | uint16_t flags; |
699 | int error; |
700 | struct mbuf *m; |
701 | struct ip *ip = NULL; |
702 | struct ip6_hdr *ip6 = NULL; |
703 | struct tcphdr *th; |
704 | u_char opt[TCP_MAXOLEN]; |
705 | unsigned int ipoptlen, optlen, hdrlen; |
706 | int idle, sendalot, lost = 0; |
707 | int sendalot_cnt = 0; |
708 | int i, sack_rxmit; |
709 | int tso = 0; |
710 | int sack_bytes_rxmt; |
711 | tcp_seq old_snd_nxt = 0; |
712 | struct sackhole *p; |
713 | #if IPSEC |
714 | size_t ipsec_optlen = 0; |
715 | #endif /* IPSEC */ |
716 | int idle_time = 0; |
717 | struct mbuf *packetlist = NULL; |
718 | struct mbuf *tp_inp_options = inp->inp_depend4.inp4_options; |
719 | int isipv6 = inp->inp_vflag & INP_IPV6; |
720 | int packchain_listadd = 0; |
721 | int so_options = so->so_options; |
722 | struct rtentry *rt; |
723 | u_int32_t svc_flags = 0, allocated_len; |
724 | #if MPTCP |
725 | boolean_t mptcp_acknow; |
726 | #endif /* MPTCP */ |
727 | boolean_t cell = FALSE; |
728 | boolean_t wifi = FALSE; |
729 | boolean_t wired = FALSE; |
730 | boolean_t sack_rescue_rxt = FALSE; |
731 | int sotc = so->so_traffic_class; |
732 | boolean_t do_not_compress = FALSE; |
733 | boolean_t sack_rxmted = FALSE; |
734 | |
735 | /* |
736 | * Determine length of data that should be transmitted, |
737 | * and flags that will be used. |
738 | * If there is some data or critical controls (SYN, RST) |
739 | * to send, then transmit; otherwise, investigate further. |
740 | */ |
741 | idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una); |
742 | |
743 | /* Since idle_time is signed integer, the following integer subtraction |
744 | * will take care of wrap around of tcp_now |
745 | */ |
746 | idle_time = tcp_now - tp->t_rcvtime; |
747 | if (idle && idle_time >= TCP_IDLETIMEOUT(tp)) { |
748 | if (CC_ALGO(tp)->after_idle != NULL && |
749 | (tp->tcp_cc_index != TCP_CC_ALGO_CUBIC_INDEX || |
750 | idle_time >= TCP_CC_CWND_NONVALIDATED_PERIOD)) { |
751 | CC_ALGO(tp)->after_idle(tp); |
752 | tcp_ccdbg_trace(tp, NULL, event: TCP_CC_IDLE_TIMEOUT); |
753 | } |
754 | |
755 | /* |
756 | * Do some other tasks that need to be done after |
757 | * idle time |
758 | */ |
759 | if (!SLIST_EMPTY(&tp->t_rxt_segments)) { |
760 | tcp_rxtseg_clean(tp); |
761 | } |
762 | |
763 | /* If stretch ack was auto-disabled, re-evaluate it */ |
764 | tcp_cc_after_idle_stretchack(tp); |
765 | tp->t_forced_acks = TCP_FORCED_ACKS_COUNT; |
766 | } |
767 | tp->t_flags &= ~TF_LASTIDLE; |
768 | if (idle) { |
769 | if (tp->t_flags & TF_MORETOCOME) { |
770 | tp->t_flags |= TF_LASTIDLE; |
771 | idle = 0; |
772 | } |
773 | } |
774 | #if MPTCP |
775 | if (tp->t_mpflags & TMPF_RESET) { |
776 | tcp_check_timer_state(tp); |
777 | /* |
778 | * Once a RST has been sent for an MPTCP subflow, |
779 | * the subflow socket stays around until deleted. |
780 | * No packets such as FINs must be sent after RST. |
781 | */ |
782 | return 0; |
783 | } |
784 | #endif /* MPTCP */ |
785 | |
786 | again: |
787 | #if MPTCP |
788 | mptcp_acknow = FALSE; |
789 | |
790 | if (so->so_flags & SOF_MP_SUBFLOW && SEQ_LT(tp->snd_nxt, tp->snd_una)) { |
791 | os_log_error(mptcp_log_handle, "%s - %lx: snd_nxt is %u and snd_una is %u, cnt %d\n" , |
792 | __func__, (unsigned long)VM_KERNEL_ADDRPERM(tp->t_mpsub->mpts_mpte), |
793 | tp->snd_nxt, tp->snd_una, sendalot_cnt); |
794 | } |
795 | #endif |
796 | do_not_compress = FALSE; |
797 | sendalot_cnt++; |
798 | |
799 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0, 0, 0, 0, 0); |
800 | |
801 | if (isipv6) { |
802 | KERNEL_DEBUG(DBG_LAYER_BEG, |
803 | ((inp->inp_fport << 16) | inp->inp_lport), |
804 | (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) | |
805 | (inp->in6p_faddr.s6_addr16[0] & 0xffff)), |
806 | sendalot, 0, 0); |
807 | } else { |
808 | KERNEL_DEBUG(DBG_LAYER_BEG, |
809 | ((inp->inp_fport << 16) | inp->inp_lport), |
810 | (((inp->inp_laddr.s_addr & 0xffff) << 16) | |
811 | (inp->inp_faddr.s_addr & 0xffff)), |
812 | sendalot, 0, 0); |
813 | } |
814 | /* |
815 | * If the route generation id changed, we need to check that our |
816 | * local (source) IP address is still valid. If it isn't either |
817 | * return error or silently do nothing (assuming the address will |
818 | * come back before the TCP connection times out). |
819 | */ |
820 | rt = inp->inp_route.ro_rt; |
821 | if (rt != NULL && ROUTE_UNUSABLE(&tp->t_inpcb->inp_route)) { |
822 | struct ifnet *ifp; |
823 | struct in_ifaddr *ia = NULL; |
824 | struct in6_ifaddr *ia6 = NULL; |
825 | int found_srcaddr = 0; |
826 | |
827 | /* disable multipages at the socket */ |
828 | somultipages(so, FALSE); |
829 | |
830 | /* Disable TSO for the socket until we know more */ |
831 | tp->t_flags &= ~TF_TSO; |
832 | |
833 | soif2kcl(so, FALSE); |
834 | |
835 | if (isipv6) { |
836 | ia6 = ifa_foraddr6(&inp->in6p_laddr); |
837 | if (ia6 != NULL) { |
838 | found_srcaddr = 1; |
839 | } |
840 | } else { |
841 | ia = ifa_foraddr(inp->inp_laddr.s_addr); |
842 | if (ia != NULL) { |
843 | found_srcaddr = 1; |
844 | } |
845 | } |
846 | |
847 | /* check that the source address is still valid */ |
848 | if (found_srcaddr == 0) { |
849 | soevent(so, |
850 | hint: (SO_FILT_HINT_LOCKED | SO_FILT_HINT_NOSRCADDR)); |
851 | |
852 | if (tp->t_state >= TCPS_CLOSE_WAIT) { |
853 | tcp_drop(tp, EADDRNOTAVAIL); |
854 | return EADDRNOTAVAIL; |
855 | } |
856 | |
857 | /* |
858 | * Set retransmit timer if it wasn't set, |
859 | * reset Persist timer and shift register as the |
860 | * advertised peer window may not be valid anymore |
861 | */ |
862 | if (tp->t_timer[TCPT_REXMT] == 0) { |
863 | tp->t_timer[TCPT_REXMT] = |
864 | OFFSET_FROM_START(tp, tp->t_rxtcur); |
865 | if (tp->t_timer[TCPT_PERSIST] != 0) { |
866 | tp->t_timer[TCPT_PERSIST] = 0; |
867 | tp->t_persist_stop = 0; |
868 | TCP_RESET_REXMT_STATE(tp); |
869 | } |
870 | } |
871 | |
872 | if (tp->t_pktlist_head != NULL) { |
873 | m_freem_list(tp->t_pktlist_head); |
874 | } |
875 | TCP_PKTLIST_CLEAR(tp); |
876 | |
877 | /* drop connection if source address isn't available */ |
878 | if (so->so_flags & SOF_NOADDRAVAIL) { |
879 | tcp_drop(tp, EADDRNOTAVAIL); |
880 | return EADDRNOTAVAIL; |
881 | } else { |
882 | TCP_LOG_OUTPUT(tp, "no source address silently ignored" ); |
883 | tcp_check_timer_state(tp); |
884 | return 0; /* silently ignore, keep data in socket: address may be back */ |
885 | } |
886 | } |
887 | if (ia != NULL) { |
888 | ifa_remref(ifa: &ia->ia_ifa); |
889 | } |
890 | |
891 | if (ia6 != NULL) { |
892 | ifa_remref(ifa: &ia6->ia_ifa); |
893 | } |
894 | |
895 | /* |
896 | * Address is still valid; check for multipages capability |
897 | * again in case the outgoing interface has changed. |
898 | */ |
899 | RT_LOCK(rt); |
900 | if ((ifp = rt->rt_ifp) != NULL) { |
901 | somultipages(so, (ifp->if_hwassist & IFNET_MULTIPAGES)); |
902 | tcp_set_tso(tp, ifp); |
903 | soif2kcl(so, (ifp->if_eflags & IFEF_2KCL)); |
904 | tcp_set_ecn(tp, ifp); |
905 | } |
906 | if (rt->rt_flags & RTF_UP) { |
907 | RT_GENID_SYNC(rt); |
908 | } |
909 | /* |
910 | * See if we should do MTU discovery. Don't do it if: |
911 | * 1) it is disabled via the sysctl |
912 | * 2) the route isn't up |
913 | * 3) the MTU is locked (if it is, then discovery |
914 | * has been disabled) |
915 | */ |
916 | |
917 | if (!path_mtu_discovery || ((rt != NULL) && |
918 | (!(rt->rt_flags & RTF_UP) || |
919 | (rt->rt_rmx.rmx_locks & RTV_MTU)))) { |
920 | tp->t_flags &= ~TF_PMTUD; |
921 | } else { |
922 | tp->t_flags |= TF_PMTUD; |
923 | } |
924 | |
925 | RT_UNLOCK(rt); |
926 | } |
927 | |
928 | if (rt != NULL) { |
929 | cell = IFNET_IS_CELLULAR(rt->rt_ifp); |
930 | wifi = (!cell && IFNET_IS_WIFI(rt->rt_ifp)); |
931 | wired = (!wifi && IFNET_IS_WIRED(rt->rt_ifp)); |
932 | } |
933 | |
934 | /* |
935 | * If we've recently taken a timeout, snd_max will be greater than |
936 | * snd_nxt. There may be SACK information that allows us to avoid |
937 | * resending already delivered data. Adjust snd_nxt accordingly. |
938 | */ |
939 | if (SACK_ENABLED(tp) && SEQ_LT(tp->snd_nxt, tp->snd_max)) { |
940 | max_len = tcp_sack_adjust(tp); |
941 | } |
942 | sendalot = 0; |
943 | off = tp->snd_nxt - tp->snd_una; |
944 | sendwin = min(a: tp->snd_wnd, b: tp->snd_cwnd); |
945 | |
946 | if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) { |
947 | sendwin = min(a: sendwin, b: slowlink_wsize); |
948 | } |
949 | |
950 | flags = tcp_outflags[tp->t_state]; |
951 | /* |
952 | * Send any SACK-generated retransmissions. If we're explicitly |
953 | * trying to send out new data (when sendalot is 1), bypass this |
954 | * function. If we retransmit in fast recovery mode, decrement |
955 | * snd_cwnd, since we're replacing a (future) new transmission |
956 | * with a retransmission now, and we previously incremented |
957 | * snd_cwnd in tcp_input(). |
958 | */ |
959 | /* |
960 | * Still in sack recovery , reset rxmit flag to zero. |
961 | */ |
962 | sack_rxmit = 0; |
963 | sack_bytes_rxmt = 0; |
964 | len = 0; |
965 | p = NULL; |
966 | if (SACK_ENABLED(tp) && IN_FASTRECOVERY(tp) && |
967 | (p = tcp_sack_output(tp, sack_bytes_rexmt: &sack_bytes_rxmt))) { |
968 | int32_t cwin; |
969 | |
970 | if (tcp_do_better_lr) { |
971 | cwin = min(a: tp->snd_wnd, b: tp->snd_cwnd) - tcp_flight_size(tp); |
972 | if (cwin <= 0 && sack_rxmted == FALSE) { |
973 | /* Allow to clock out at least on per period */ |
974 | cwin = tp->t_maxseg; |
975 | } |
976 | |
977 | sack_rxmted = TRUE; |
978 | } else { |
979 | cwin = min(a: tp->snd_wnd, b: tp->snd_cwnd) - sack_bytes_rxmt; |
980 | } |
981 | if (cwin < 0) { |
982 | cwin = 0; |
983 | } |
984 | /* Do not retransmit SACK segments beyond snd_recover */ |
985 | if (SEQ_GT(p->end, tp->snd_recover)) { |
986 | /* |
987 | * (At least) part of sack hole extends beyond |
988 | * snd_recover. Check to see if we can rexmit data |
989 | * for this hole. |
990 | */ |
991 | if (SEQ_GEQ(p->rxmit, tp->snd_recover)) { |
992 | /* |
993 | * Can't rexmit any more data for this hole. |
994 | * That data will be rexmitted in the next |
995 | * sack recovery episode, when snd_recover |
996 | * moves past p->rxmit. |
997 | */ |
998 | p = NULL; |
999 | goto after_sack_rexmit; |
1000 | } else { |
1001 | /* Can rexmit part of the current hole */ |
1002 | len = ((int32_t)min(a: cwin, |
1003 | b: tp->snd_recover - p->rxmit)); |
1004 | } |
1005 | } else { |
1006 | len = ((int32_t)min(a: cwin, b: p->end - p->rxmit)); |
1007 | } |
1008 | if (len > 0) { |
1009 | off = p->rxmit - tp->snd_una; |
1010 | sack_rxmit = 1; |
1011 | sendalot = 1; |
1012 | /* Everything sent after snd_nxt will allow us to account for fast-retransmit of the retransmitted segment */ |
1013 | tp->send_highest_sack = tp->snd_nxt; |
1014 | tp->t_new_dupacks = 0; |
1015 | tcpstat.tcps_sack_rexmits++; |
1016 | tcpstat.tcps_sack_rexmit_bytes += |
1017 | min(a: len, b: tp->t_maxseg); |
1018 | } else { |
1019 | len = 0; |
1020 | } |
1021 | } |
1022 | after_sack_rexmit: |
1023 | /* |
1024 | * Get standard flags, and add SYN or FIN if requested by 'hidden' |
1025 | * state flags. |
1026 | */ |
1027 | if (tp->t_flags & TF_NEEDFIN) { |
1028 | flags |= TH_FIN; |
1029 | } |
1030 | |
1031 | /* |
1032 | * If in persist timeout with window of 0, send 1 byte. |
1033 | * Otherwise, if window is small but nonzero |
1034 | * and timer expired, we will send what we can |
1035 | * and go to transmit state. |
1036 | */ |
1037 | if (tp->t_flagsext & TF_FORCE) { |
1038 | if (sendwin == 0) { |
1039 | /* |
1040 | * If we still have some data to send, then |
1041 | * clear the FIN bit. Usually this would |
1042 | * happen below when it realizes that we |
1043 | * aren't sending all the data. However, |
1044 | * if we have exactly 1 byte of unsent data, |
1045 | * then it won't clear the FIN bit below, |
1046 | * and if we are in persist state, we wind |
1047 | * up sending the packet without recording |
1048 | * that we sent the FIN bit. |
1049 | * |
1050 | * We can't just blindly clear the FIN bit, |
1051 | * because if we don't have any more data |
1052 | * to send then the probe will be the FIN |
1053 | * itself. |
1054 | */ |
1055 | if (off < so->so_snd.sb_cc) { |
1056 | flags &= ~TH_FIN; |
1057 | } |
1058 | sendwin = 1; |
1059 | } else { |
1060 | tp->t_timer[TCPT_PERSIST] = 0; |
1061 | tp->t_persist_stop = 0; |
1062 | TCP_RESET_REXMT_STATE(tp); |
1063 | } |
1064 | } |
1065 | |
1066 | /* |
1067 | * If snd_nxt == snd_max and we have transmitted a FIN, the |
1068 | * offset will be > 0 even if so_snd.sb_cc is 0, resulting in |
1069 | * a negative length. This can also occur when TCP opens up |
1070 | * its congestion window while receiving additional duplicate |
1071 | * acks after fast-retransmit because TCP will reset snd_nxt |
1072 | * to snd_max after the fast-retransmit. |
1073 | * |
1074 | * In the normal retransmit-FIN-only case, however, snd_nxt will |
1075 | * be set to snd_una, the offset will be 0, and the length may |
1076 | * wind up 0. |
1077 | * |
1078 | * If sack_rxmit is true we are retransmitting from the scoreboard |
1079 | * in which case len is already set. |
1080 | */ |
1081 | if (sack_rxmit == 0) { |
1082 | if (sack_bytes_rxmt == 0) { |
1083 | len = min(a: so->so_snd.sb_cc, b: sendwin) - off; |
1084 | } else { |
1085 | int32_t cwin; |
1086 | |
1087 | if (tcp_do_better_lr) { |
1088 | cwin = tp->snd_cwnd - tcp_flight_size(tp); |
1089 | } else { |
1090 | cwin = tp->snd_cwnd - |
1091 | (tp->snd_nxt - tp->sack_newdata) - |
1092 | sack_bytes_rxmt; |
1093 | } |
1094 | if (cwin < 0) { |
1095 | cwin = 0; |
1096 | } |
1097 | /* |
1098 | * We are inside of a SACK recovery episode and are |
1099 | * sending new data, having retransmitted all the |
1100 | * data possible in the scoreboard. |
1101 | */ |
1102 | len = min(a: so->so_snd.sb_cc, b: tp->snd_wnd) - off; |
1103 | /* |
1104 | * Don't remove this (len > 0) check ! |
1105 | * We explicitly check for len > 0 here (although it |
1106 | * isn't really necessary), to work around a gcc |
1107 | * optimization issue - to force gcc to compute |
1108 | * len above. Without this check, the computation |
1109 | * of len is bungled by the optimizer. |
1110 | */ |
1111 | if (len > 0) { |
1112 | len = imin(a: len, b: cwin); |
1113 | } else { |
1114 | len = 0; |
1115 | } |
1116 | /* |
1117 | * At this point SACK recovery can not send any |
1118 | * data from scoreboard or any new data. Check |
1119 | * if we can do a rescue retransmit towards the |
1120 | * tail end of recovery window. |
1121 | */ |
1122 | if (len == 0 && cwin > 0 && |
1123 | SEQ_LT(tp->snd_fack, tp->snd_recover) && |
1124 | !(tp->t_flagsext & TF_RESCUE_RXT)) { |
1125 | len = min(a: (tp->snd_recover - tp->snd_fack), |
1126 | b: tp->t_maxseg); |
1127 | len = imin(a: len, b: cwin); |
1128 | old_snd_nxt = tp->snd_nxt; |
1129 | sack_rescue_rxt = TRUE; |
1130 | tp->snd_nxt = tp->snd_recover - len; |
1131 | /* |
1132 | * If FIN has been sent, snd_max |
1133 | * must have been advanced to cover it. |
1134 | */ |
1135 | if ((tp->t_flags & TF_SENTFIN) && |
1136 | tp->snd_max == tp->snd_recover) { |
1137 | tp->snd_nxt--; |
1138 | } |
1139 | |
1140 | off = tp->snd_nxt - tp->snd_una; |
1141 | sendalot = 0; |
1142 | tp->t_flagsext |= TF_RESCUE_RXT; |
1143 | } |
1144 | } |
1145 | } |
1146 | |
1147 | if (max_len != 0 && len > 0) { |
1148 | len = min(a: len, b: max_len); |
1149 | } |
1150 | |
1151 | /* |
1152 | * Lop off SYN bit if it has already been sent. However, if this |
1153 | * is SYN-SENT state and if segment contains data and if we don't |
1154 | * know that foreign host supports TAO, suppress sending segment. |
1155 | */ |
1156 | if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) { |
1157 | if (tp->t_state == TCPS_SYN_RECEIVED && tfo_enabled(tp) && tp->snd_nxt == tp->snd_una + 1) { |
1158 | /* We are sending the SYN again! */ |
1159 | off--; |
1160 | len++; |
1161 | } else { |
1162 | if (tp->t_state != TCPS_SYN_RECEIVED || tfo_enabled(tp)) { |
1163 | flags &= ~TH_SYN; |
1164 | } |
1165 | |
1166 | off--; |
1167 | len++; |
1168 | if (len > 0 && tp->t_state == TCPS_SYN_SENT) { |
1169 | while (inp->inp_sndinprog_cnt == 0 && |
1170 | tp->t_pktlist_head != NULL) { |
1171 | packetlist = tp->t_pktlist_head; |
1172 | packchain_listadd = tp->t_lastchain; |
1173 | packchain_sent++; |
1174 | TCP_PKTLIST_CLEAR(tp); |
1175 | |
1176 | error = tcp_ip_output(so, tp, packetlist, |
1177 | packchain_listadd, tp_inp_options, |
1178 | (so_options & SO_DONTROUTE), |
1179 | (sack_rxmit || (sack_bytes_rxmt != 0)), |
1180 | isipv6); |
1181 | } |
1182 | |
1183 | /* |
1184 | * tcp was closed while we were in ip, |
1185 | * resume close |
1186 | */ |
1187 | if (inp->inp_sndinprog_cnt == 0 && |
1188 | (tp->t_flags & TF_CLOSING)) { |
1189 | tp->t_flags &= ~TF_CLOSING; |
1190 | (void) tcp_close(tp); |
1191 | } else { |
1192 | tcp_check_timer_state(tp); |
1193 | } |
1194 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, |
1195 | 0, 0, 0, 0, 0); |
1196 | return 0; |
1197 | } |
1198 | } |
1199 | } |
1200 | |
1201 | /* |
1202 | * Be careful not to send data and/or FIN on SYN segments. |
1203 | * This measure is needed to prevent interoperability problems |
1204 | * with not fully conformant TCP implementations. |
1205 | * |
1206 | * In case of TFO, we handle the setting of the len in |
1207 | * tcp_tfo_check. In case TFO is not enabled, never ever send |
1208 | * SYN+data. |
1209 | */ |
1210 | if ((flags & TH_SYN) && !tfo_enabled(tp)) { |
1211 | len = 0; |
1212 | flags &= ~TH_FIN; |
1213 | } |
1214 | |
1215 | /* |
1216 | * Don't send a RST with data. |
1217 | */ |
1218 | if (flags & TH_RST) { |
1219 | len = 0; |
1220 | } |
1221 | |
1222 | if ((flags & TH_SYN) && tp->t_state <= TCPS_SYN_SENT && tfo_enabled(tp)) { |
1223 | len = tcp_tfo_check(tp, len); |
1224 | } |
1225 | |
1226 | /* |
1227 | * The check here used to be (len < 0). Some times len is zero |
1228 | * when the congestion window is closed and we need to check |
1229 | * if persist timer has to be set in that case. But don't set |
1230 | * persist until connection is established. |
1231 | */ |
1232 | if (len <= 0 && !(flags & TH_SYN)) { |
1233 | /* |
1234 | * If FIN has been sent but not acked, |
1235 | * but we haven't been called to retransmit, |
1236 | * len will be < 0. Otherwise, window shrank |
1237 | * after we sent into it. If window shrank to 0, |
1238 | * cancel pending retransmit, pull snd_nxt back |
1239 | * to (closed) window, and set the persist timer |
1240 | * if it isn't already going. If the window didn't |
1241 | * close completely, just wait for an ACK. |
1242 | */ |
1243 | len = 0; |
1244 | if (sendwin == 0) { |
1245 | tp->t_timer[TCPT_REXMT] = 0; |
1246 | tp->t_timer[TCPT_PTO] = 0; |
1247 | TCP_RESET_REXMT_STATE(tp); |
1248 | tp->snd_nxt = tp->snd_una; |
1249 | off = 0; |
1250 | if (tp->t_timer[TCPT_PERSIST] == 0) { |
1251 | tcp_setpersist(tp); |
1252 | } |
1253 | } |
1254 | } |
1255 | |
1256 | /* |
1257 | * Automatic sizing of send socket buffer. Increase the send |
1258 | * socket buffer size if all of the following criteria are met |
1259 | * 1. the receiver has enough buffer space for this data |
1260 | * 2. send buffer is filled to 7/8th with data (so we actually |
1261 | * have data to make use of it); |
1262 | * 3. our send window (slow start and congestion controlled) is |
1263 | * larger than sent but unacknowledged data in send buffer. |
1264 | */ |
1265 | if (!INP_WAIT_FOR_IF_FEEDBACK(inp) && !IN_FASTRECOVERY(tp) && |
1266 | (so->so_snd.sb_flags & (SB_AUTOSIZE | SB_TRIM)) == SB_AUTOSIZE) { |
1267 | if ((tp->snd_wnd / 4 * 5) >= so->so_snd.sb_hiwat && |
1268 | so->so_snd.sb_cc >= (so->so_snd.sb_hiwat / 8 * 7) && |
1269 | sendwin >= (so->so_snd.sb_cc - (tp->snd_nxt - tp->snd_una))) { |
1270 | if (sbreserve(sb: &so->so_snd, |
1271 | cc: min(a: so->so_snd.sb_hiwat + tcp_autosndbuf_inc, |
1272 | b: tcp_autosndbuf_max)) == 1) { |
1273 | so->so_snd.sb_idealsize = so->so_snd.sb_hiwat; |
1274 | } |
1275 | } |
1276 | } |
1277 | |
1278 | /* |
1279 | * Truncate to the maximum segment length or enable TCP Segmentation |
1280 | * Offloading (if supported by hardware) and ensure that FIN is removed |
1281 | * if the length no longer contains the last data byte. |
1282 | * |
1283 | * TSO may only be used if we are in a pure bulk sending state. |
1284 | * The presence of TCP-MD5, SACK retransmits, SACK advertizements, |
1285 | * filters and IP options, as well as disabling hardware checksum |
1286 | * offload prevent using TSO. With TSO the TCP header is the same |
1287 | * (except for the sequence number) for all generated packets. This |
1288 | * makes it impossible to transmit any options which vary per generated |
1289 | * segment or packet. |
1290 | * |
1291 | * The length of TSO bursts is limited to TCP_MAXWIN. That limit and |
1292 | * removal of FIN (if not already catched here) are handled later after |
1293 | * the exact length of the TCP options are known. |
1294 | */ |
1295 | #if IPSEC |
1296 | /* |
1297 | * Pre-calculate here as we save another lookup into the darknesses |
1298 | * of IPsec that way and can actually decide if TSO is ok. |
1299 | */ |
1300 | if (ipsec_bypass == 0) { |
1301 | ipsec_optlen = ipsec_hdrsiz_tcp(tp); |
1302 | } |
1303 | #endif |
1304 | if (len > tp->t_maxseg) { |
1305 | if ((tp->t_flags & TF_TSO) && tcp_do_tso && hwcksum_tx && |
1306 | kipf_count == 0 && |
1307 | tp->rcv_numsacks == 0 && sack_rxmit == 0 && |
1308 | sack_bytes_rxmt == 0 && |
1309 | inp->inp_options == NULL && |
1310 | inp->in6p_options == NULL |
1311 | #if IPSEC |
1312 | && ipsec_optlen == 0 |
1313 | #endif |
1314 | ) { |
1315 | tso = 1; |
1316 | sendalot = 0; |
1317 | } else { |
1318 | len = tp->t_maxseg; |
1319 | sendalot = 1; |
1320 | tso = 0; |
1321 | } |
1322 | } else { |
1323 | tso = 0; |
1324 | } |
1325 | |
1326 | /* Send one segment or less as a tail loss probe */ |
1327 | if (tp->t_flagsext & TF_SENT_TLPROBE) { |
1328 | len = min(a: len, b: tp->t_maxseg); |
1329 | sendalot = 0; |
1330 | tso = 0; |
1331 | } |
1332 | |
1333 | #if MPTCP |
1334 | if (so->so_flags & SOF_MP_SUBFLOW && off < 0) { |
1335 | os_log_error(mptcp_log_handle, "%s - %lx: offset is negative! len %d off %d\n" , |
1336 | __func__, (unsigned long)VM_KERNEL_ADDRPERM(tp->t_mpsub->mpts_mpte), |
1337 | len, off); |
1338 | } |
1339 | |
1340 | if ((so->so_flags & SOF_MP_SUBFLOW) && |
1341 | !(tp->t_mpflags & TMPF_TCP_FALLBACK)) { |
1342 | int newlen = len; |
1343 | struct mptcb *mp_tp = tptomptp(tp); |
1344 | if (tp->t_state >= TCPS_ESTABLISHED && |
1345 | (tp->t_mpflags & TMPF_SND_MPPRIO || |
1346 | tp->t_mpflags & TMPF_SND_REM_ADDR || |
1347 | tp->t_mpflags & TMPF_SND_MPFAIL || |
1348 | (tp->t_mpflags & TMPF_SND_KEYS && |
1349 | mp_tp->mpt_version == MPTCP_VERSION_0) || |
1350 | tp->t_mpflags & TMPF_SND_JACK || |
1351 | tp->t_mpflags & TMPF_MPTCP_ECHO_ADDR)) { |
1352 | if (len > 0) { |
1353 | len = 0; |
1354 | tso = 0; |
1355 | } |
1356 | /* |
1357 | * On a new subflow, don't try to send again, because |
1358 | * we are still waiting for the fourth ack. |
1359 | */ |
1360 | if (!(tp->t_mpflags & TMPF_PREESTABLISHED)) { |
1361 | sendalot = 1; |
1362 | } |
1363 | mptcp_acknow = TRUE; |
1364 | } else { |
1365 | mptcp_acknow = FALSE; |
1366 | } |
1367 | /* |
1368 | * The contiguous bytes in the subflow socket buffer can be |
1369 | * discontiguous at the MPTCP level. Since only one DSS |
1370 | * option can be sent in one packet, reduce length to match |
1371 | * the contiguous MPTCP level. Set sendalot to send remainder. |
1372 | */ |
1373 | if (len > 0 && off >= 0) { |
1374 | newlen = mptcp_adj_sendlen(so, off); |
1375 | } |
1376 | |
1377 | if (newlen < len) { |
1378 | len = newlen; |
1379 | if (len <= tp->t_maxseg) { |
1380 | tso = 0; |
1381 | } |
1382 | } |
1383 | } |
1384 | #endif /* MPTCP */ |
1385 | |
1386 | if (sack_rxmit) { |
1387 | if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc)) { |
1388 | flags &= ~TH_FIN; |
1389 | } |
1390 | } else { |
1391 | if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc)) { |
1392 | flags &= ~TH_FIN; |
1393 | } |
1394 | } |
1395 | /* |
1396 | * Compare available window to amount of window |
1397 | * known to peer (as advertised window less |
1398 | * next expected input). If the difference is at least two |
1399 | * max size segments, or at least 25% of the maximum possible |
1400 | * window, then want to send a window update to peer. |
1401 | */ |
1402 | recwin = tcp_sbspace(tp); |
1403 | |
1404 | if (!(so->so_flags & SOF_MP_SUBFLOW)) { |
1405 | if (recwin < (int32_t)(so->so_rcv.sb_hiwat / 4) && |
1406 | recwin < (int)tp->t_maxseg) { |
1407 | recwin = 0; |
1408 | } |
1409 | } else { |
1410 | struct mptcb *mp_tp = tptomptp(tp); |
1411 | struct socket *mp_so = mptetoso(mpte: mp_tp->mpt_mpte); |
1412 | |
1413 | if (recwin < (int32_t)(mp_so->so_rcv.sb_hiwat / 4) && |
1414 | recwin < (int)tp->t_maxseg) { |
1415 | recwin = 0; |
1416 | } |
1417 | } |
1418 | |
1419 | #if TRAFFIC_MGT |
1420 | if (tcp_recv_bg == 1 || IS_TCP_RECV_BG(so)) { |
1421 | /* |
1422 | * Timestamp MUST be supported to use rledbat unless we haven't |
1423 | * yet negotiated it. |
1424 | */ |
1425 | if (TCP_RLEDBAT_ENABLED(tp) || (tcp_rledbat && tp->t_state < |
1426 | TCPS_ESTABLISHED)) { |
1427 | if (recwin > 0 && tcp_cc_rledbat.get_rlwin != NULL) { |
1428 | /* Min of flow control window and rledbat window */ |
1429 | recwin = imin(a: recwin, b: tcp_cc_rledbat.get_rlwin(tp)); |
1430 | } |
1431 | } else if (recwin > 0 && tcp_recv_throttle(tp)) { |
1432 | uint32_t min_iaj_win = tcp_min_iaj_win * tp->t_maxseg; |
1433 | uint32_t bg_rwintop = tp->rcv_adv; |
1434 | if (SEQ_LT(bg_rwintop, tp->rcv_nxt + min_iaj_win)) { |
1435 | bg_rwintop = tp->rcv_nxt + min_iaj_win; |
1436 | } |
1437 | recwin = imin(a: (int32_t)(bg_rwintop - tp->rcv_nxt), |
1438 | b: recwin); |
1439 | if (recwin < 0) { |
1440 | recwin = 0; |
1441 | } |
1442 | } |
1443 | } |
1444 | #endif /* TRAFFIC_MGT */ |
1445 | |
1446 | if (recwin > (int32_t)(TCP_MAXWIN << tp->rcv_scale)) { |
1447 | recwin = (int32_t)(TCP_MAXWIN << tp->rcv_scale); |
1448 | } |
1449 | |
1450 | if (!(so->so_flags & SOF_MP_SUBFLOW)) { |
1451 | if (recwin < (int32_t)(tp->rcv_adv - tp->rcv_nxt)) { |
1452 | recwin = (int32_t)(tp->rcv_adv - tp->rcv_nxt); |
1453 | } |
1454 | } else { |
1455 | struct mptcb *mp_tp = tptomptp(tp); |
1456 | int64_t recwin_announced = (int64_t)(mp_tp->mpt_rcvadv - mp_tp->mpt_rcvnxt); |
1457 | |
1458 | /* Don't remove what we announced at the MPTCP-layer */ |
1459 | VERIFY(recwin_announced < INT32_MAX && recwin_announced > INT32_MIN); |
1460 | if (recwin < (int32_t)recwin_announced) { |
1461 | recwin = (int32_t)recwin_announced; |
1462 | } |
1463 | } |
1464 | |
1465 | /* |
1466 | * Sender silly window avoidance. We transmit under the following |
1467 | * conditions when len is non-zero: |
1468 | * |
1469 | * - we've timed out (e.g. persist timer) |
1470 | * - we need to retransmit |
1471 | * - We have a full segment (or more with TSO) |
1472 | * - This is the last buffer in a write()/send() and we are |
1473 | * either idle or running NODELAY |
1474 | * - we have more then 1/2 the maximum send window's worth of |
1475 | * data (receiver may be limited the window size) |
1476 | */ |
1477 | if (len) { |
1478 | if (tp->t_flagsext & TF_FORCE) { |
1479 | goto send; |
1480 | } |
1481 | if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { |
1482 | goto send; |
1483 | } |
1484 | if (sack_rxmit) { |
1485 | goto send; |
1486 | } |
1487 | |
1488 | /* |
1489 | * If this here is the first segment after SYN/ACK and TFO |
1490 | * is being used, then we always send it, regardless of Nagle,... |
1491 | */ |
1492 | if (tp->t_state == TCPS_SYN_RECEIVED && |
1493 | tfo_enabled(tp) && |
1494 | (tp->t_tfo_flags & TFO_F_COOKIE_VALID) && |
1495 | tp->snd_nxt == tp->iss + 1) { |
1496 | goto send; |
1497 | } |
1498 | |
1499 | /* |
1500 | * Send new data on the connection only if it is |
1501 | * not flow controlled |
1502 | */ |
1503 | if (!INP_WAIT_FOR_IF_FEEDBACK(inp) || |
1504 | tp->t_state != TCPS_ESTABLISHED) { |
1505 | if (off + len == tp->snd_wnd) { |
1506 | /* We are limited by the receiver's window... */ |
1507 | if (tp->t_rcvwnd_limited_start_time == 0) { |
1508 | tp->t_rcvwnd_limited_start_time = net_uptime_us(); |
1509 | } |
1510 | } else { |
1511 | /* We are no more limited by the receiver's window... */ |
1512 | if (tp->t_rcvwnd_limited_start_time != 0) { |
1513 | uint64_t now = net_uptime_us(); |
1514 | |
1515 | ASSERT(now >= tp->t_rcvwnd_limited_start_time); |
1516 | |
1517 | tp->t_rcvwnd_limited_total_time += (now - tp->t_rcvwnd_limited_start_time); |
1518 | |
1519 | tp->t_rcvwnd_limited_start_time = 0; |
1520 | } |
1521 | } |
1522 | |
1523 | if (len >= tp->t_maxseg) { |
1524 | goto send; |
1525 | } |
1526 | |
1527 | if (!(tp->t_flags & TF_MORETOCOME) && |
1528 | (idle || tp->t_flags & TF_NODELAY || |
1529 | (tp->t_flags & TF_MAXSEGSNT) || |
1530 | ALLOW_LIMITED_TRANSMIT(tp)) && |
1531 | (tp->t_flags & TF_NOPUSH) == 0 && |
1532 | (len + off >= so->so_snd.sb_cc || |
1533 | /* |
1534 | * MPTCP needs to respect the DSS-mappings. So, it |
1535 | * may be sending data that *could* have been |
1536 | * coalesced, but cannot because of |
1537 | * mptcp_adj_sendlen(). |
1538 | */ |
1539 | so->so_flags & SOF_MP_SUBFLOW)) { |
1540 | goto send; |
1541 | } |
1542 | if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0) { |
1543 | goto send; |
1544 | } |
1545 | } else { |
1546 | tcpstat.tcps_fcholdpacket++; |
1547 | } |
1548 | } |
1549 | |
1550 | if (recwin > 0) { |
1551 | /* |
1552 | * "adv" is the amount we can increase the window, |
1553 | * taking into account that we are limited by |
1554 | * TCP_MAXWIN << tp->rcv_scale. |
1555 | */ |
1556 | int32_t adv, oldwin = 0; |
1557 | adv = imin(a: recwin, b: (int)TCP_MAXWIN << tp->rcv_scale) - |
1558 | (tp->rcv_adv - tp->rcv_nxt); |
1559 | |
1560 | if (SEQ_GT(tp->rcv_adv, tp->rcv_nxt)) { |
1561 | oldwin = tp->rcv_adv - tp->rcv_nxt; |
1562 | } |
1563 | |
1564 | if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY) { |
1565 | if (adv >= (int32_t) (2 * tp->t_maxseg)) { |
1566 | /* |
1567 | * Update only if the resulting scaled value of |
1568 | * the window changed, or if there is a change in |
1569 | * the sequence since the last ack. This avoids |
1570 | * what appears as dupe ACKS (see rdar://5640997) |
1571 | * |
1572 | * If streaming is detected avoid sending too many |
1573 | * window updates. We will depend on the delack |
1574 | * timer to send a window update when needed. |
1575 | * |
1576 | * If there is more data to read, don't send an ACK. |
1577 | * Otherwise we will end up sending many ACKs if the |
1578 | * application is doing micro-reads. |
1579 | */ |
1580 | if (!(tp->t_flags & TF_STRETCHACK) && |
1581 | (tp->last_ack_sent != tp->rcv_nxt || |
1582 | ((oldwin + adv) >> tp->rcv_scale) > |
1583 | (oldwin >> tp->rcv_scale))) { |
1584 | goto send; |
1585 | } |
1586 | } |
1587 | } else { |
1588 | if (adv >= (int32_t) (2 * tp->t_maxseg)) { |
1589 | /* |
1590 | * ACK every second full-sized segment, if the |
1591 | * ACK is advancing or the window becomes bigger |
1592 | */ |
1593 | if (so->so_rcv.sb_cc < so->so_rcv.sb_lowat && |
1594 | (tp->last_ack_sent != tp->rcv_nxt || |
1595 | ((oldwin + adv) >> tp->rcv_scale) > |
1596 | (oldwin >> tp->rcv_scale))) { |
1597 | goto send; |
1598 | } |
1599 | } else if (tp->t_flags & TF_DELACK) { |
1600 | /* |
1601 | * If we delayed the ACK and the window |
1602 | * is not advancing by a lot (< 2MSS), ACK |
1603 | * immediately if the last incoming packet had |
1604 | * the push flag set and we emptied the buffer. |
1605 | * |
1606 | * This takes care of a sender doing small |
1607 | * repeated writes with Nagle enabled. |
1608 | */ |
1609 | if (so->so_rcv.sb_cc == 0 && |
1610 | tp->last_ack_sent != tp->rcv_nxt && |
1611 | (tp->t_flagsext & TF_LAST_IS_PSH)) { |
1612 | goto send; |
1613 | } |
1614 | } |
1615 | } |
1616 | if (4 * adv >= (int32_t) so->so_rcv.sb_hiwat) { |
1617 | goto send; |
1618 | } |
1619 | |
1620 | /* |
1621 | * Make sure that the delayed ack timer is set if |
1622 | * we delayed sending a window update because of |
1623 | * streaming detection. |
1624 | */ |
1625 | if (tcp_ack_strategy == TCP_ACK_STRATEGY_LEGACY && |
1626 | (tp->t_flags & TF_STRETCHACK) && |
1627 | !(tp->t_flags & TF_DELACK)) { |
1628 | tp->t_flags |= TF_DELACK; |
1629 | tp->t_timer[TCPT_DELACK] = |
1630 | OFFSET_FROM_START(tp, tcp_delack); |
1631 | } |
1632 | } |
1633 | |
1634 | /* |
1635 | * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW |
1636 | * is also a catch-all for the retransmit timer timeout case. |
1637 | */ |
1638 | if (tp->t_flags & TF_ACKNOW) { |
1639 | if (tp->t_forced_acks > 0) { |
1640 | tp->t_forced_acks--; |
1641 | } |
1642 | goto send; |
1643 | } |
1644 | if ((flags & TH_RST) || (flags & TH_SYN)) { |
1645 | goto send; |
1646 | } |
1647 | if (SEQ_GT(tp->snd_up, tp->snd_una)) { |
1648 | goto send; |
1649 | } |
1650 | #if MPTCP |
1651 | if (mptcp_acknow) { |
1652 | goto send; |
1653 | } |
1654 | #endif /* MPTCP */ |
1655 | /* |
1656 | * If our state indicates that FIN should be sent |
1657 | * and we have not yet done so, then we need to send. |
1658 | */ |
1659 | if ((flags & TH_FIN) && |
1660 | (!(tp->t_flags & TF_SENTFIN) || tp->snd_nxt == tp->snd_una)) { |
1661 | goto send; |
1662 | } |
1663 | /* |
1664 | * In SACK, it is possible for tcp_output to fail to send a segment |
1665 | * after the retransmission timer has been turned off. Make sure |
1666 | * that the retransmission timer is set. |
1667 | */ |
1668 | if (SACK_ENABLED(tp) && (tp->t_state >= TCPS_ESTABLISHED) && |
1669 | SEQ_GT(tp->snd_max, tp->snd_una) && |
1670 | tp->t_timer[TCPT_REXMT] == 0 && |
1671 | tp->t_timer[TCPT_PERSIST] == 0) { |
1672 | tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, |
1673 | tp->t_rxtcur); |
1674 | goto just_return; |
1675 | } |
1676 | /* |
1677 | * TCP window updates are not reliable, rather a polling protocol |
1678 | * using ``persist'' packets is used to insure receipt of window |
1679 | * updates. The three ``states'' for the output side are: |
1680 | * idle not doing retransmits or persists |
1681 | * persisting to move a small or zero window |
1682 | * (re)transmitting and thereby not persisting |
1683 | * |
1684 | * tp->t_timer[TCPT_PERSIST] |
1685 | * is set when we are in persist state. |
1686 | * tp->t_force |
1687 | * is set when we are called to send a persist packet. |
1688 | * tp->t_timer[TCPT_REXMT] |
1689 | * is set when we are retransmitting |
1690 | * The output side is idle when both timers are zero. |
1691 | * |
1692 | * If send window is too small, there is data to transmit, and no |
1693 | * retransmit or persist is pending, then go to persist state. |
1694 | * If nothing happens soon, send when timer expires: |
1695 | * if window is nonzero, transmit what we can, |
1696 | * otherwise force out a byte. |
1697 | */ |
1698 | if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 && |
1699 | tp->t_timer[TCPT_PERSIST] == 0) { |
1700 | TCP_RESET_REXMT_STATE(tp); |
1701 | tcp_setpersist(tp); |
1702 | } |
1703 | just_return: |
1704 | /* |
1705 | * If there is no reason to send a segment, just return. |
1706 | * but if there is some packets left in the packet list, send them now. |
1707 | */ |
1708 | while (inp->inp_sndinprog_cnt == 0 && |
1709 | tp->t_pktlist_head != NULL) { |
1710 | packetlist = tp->t_pktlist_head; |
1711 | packchain_listadd = tp->t_lastchain; |
1712 | packchain_sent++; |
1713 | TCP_PKTLIST_CLEAR(tp); |
1714 | |
1715 | error = tcp_ip_output(so, tp, packetlist, |
1716 | packchain_listadd, |
1717 | tp_inp_options, (so_options & SO_DONTROUTE), |
1718 | (sack_rxmit || (sack_bytes_rxmt != 0)), isipv6); |
1719 | } |
1720 | /* tcp was closed while we were in ip; resume close */ |
1721 | if (inp->inp_sndinprog_cnt == 0 && |
1722 | (tp->t_flags & TF_CLOSING)) { |
1723 | tp->t_flags &= ~TF_CLOSING; |
1724 | (void) tcp_close(tp); |
1725 | } else { |
1726 | tcp_check_timer_state(tp); |
1727 | } |
1728 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0); |
1729 | return 0; |
1730 | |
1731 | send: |
1732 | /* |
1733 | * Set TF_MAXSEGSNT flag if the segment size is greater than |
1734 | * the max segment size. |
1735 | */ |
1736 | if (len > 0) { |
1737 | do_not_compress = TRUE; |
1738 | |
1739 | if (len >= tp->t_maxseg) { |
1740 | tp->t_flags |= TF_MAXSEGSNT; |
1741 | } else { |
1742 | tp->t_flags &= ~TF_MAXSEGSNT; |
1743 | } |
1744 | } |
1745 | /* |
1746 | * If we are connected and no segment has been ACKed or SACKed yet and we |
1747 | * hit a retransmission timeout, then we should disable AccECN option |
1748 | * for the rest of the connection. |
1749 | */ |
1750 | if (TCP_ACC_ECN_ON(tp) && tp->t_state == TCPS_ESTABLISHED && |
1751 | tp->snd_una == tp->iss + 1 && (tp->snd_fack == 0) |
1752 | && tp->t_rxtshift > 0) { |
1753 | if ((tp->ecn_flags & TE_RETRY_WITHOUT_ACO) == 0) { |
1754 | tp->ecn_flags |= TE_RETRY_WITHOUT_ACO; |
1755 | } |
1756 | } |
1757 | /* |
1758 | * Before ESTABLISHED, force sending of initial options |
1759 | * unless TCP set not to do any options. |
1760 | * NOTE: we assume that the IP/TCP header plus TCP options |
1761 | * always fit in a single mbuf, leaving room for a maximum |
1762 | * link header, i.e. |
1763 | * max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MCLBYTES |
1764 | */ |
1765 | optlen = 0; |
1766 | if (isipv6) { |
1767 | hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr); |
1768 | } else { |
1769 | hdrlen = sizeof(struct tcpiphdr); |
1770 | } |
1771 | if (flags & TH_SYN) { |
1772 | tp->snd_nxt = tp->iss; |
1773 | if ((tp->t_flags & TF_NOOPT) == 0) { |
1774 | u_short mss; |
1775 | |
1776 | opt[0] = TCPOPT_MAXSEG; |
1777 | opt[1] = TCPOLEN_MAXSEG; |
1778 | mss = htons((u_short) tcp_mssopt(tp)); |
1779 | (void)memcpy(dst: opt + 2, src: &mss, n: sizeof(mss)); |
1780 | optlen = TCPOLEN_MAXSEG; |
1781 | |
1782 | if ((tp->t_flags & TF_REQ_SCALE) && |
1783 | ((flags & TH_ACK) == 0 || |
1784 | (tp->t_flags & TF_RCVD_SCALE))) { |
1785 | *((u_int32_t *)(void *)(opt + optlen)) = htonl( |
1786 | TCPOPT_NOP << 24 | |
1787 | TCPOPT_WINDOW << 16 | |
1788 | TCPOLEN_WINDOW << 8 | |
1789 | tp->request_r_scale); |
1790 | optlen += 4; |
1791 | } |
1792 | #if MPTCP |
1793 | if (mptcp_enable && (so->so_flags & SOF_MP_SUBFLOW)) { |
1794 | optlen = mptcp_setup_syn_opts(so, opt, optlen); |
1795 | } |
1796 | #endif /* MPTCP */ |
1797 | } |
1798 | } |
1799 | |
1800 | /* |
1801 | * Send a timestamp and echo-reply if this is a SYN and our side |
1802 | * wants to use timestamps (TF_REQ_TSTMP is set) or both our side |
1803 | * and our peer have sent timestamps in our SYN's. |
1804 | */ |
1805 | if ((tp->t_flags & (TF_REQ_TSTMP | TF_NOOPT)) == TF_REQ_TSTMP && |
1806 | (flags & TH_RST) == 0 && |
1807 | ((flags & TH_ACK) == 0 || |
1808 | (tp->t_flags & TF_RCVD_TSTMP))) { |
1809 | u_int32_t *lp = (u_int32_t *)(void *)(opt + optlen); |
1810 | |
1811 | /* Form timestamp option as shown in appendix A of RFC 1323. */ |
1812 | *lp++ = htonl(TCPOPT_TSTAMP_HDR); |
1813 | *lp++ = htonl(tcp_now + tp->t_ts_offset); |
1814 | *lp = htonl(tp->ts_recent); |
1815 | optlen += TCPOLEN_TSTAMP_APPA; |
1816 | } |
1817 | |
1818 | if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) { |
1819 | /* |
1820 | * Tack on the SACK permitted option *last*. |
1821 | * And do padding of options after tacking this on. |
1822 | * This is because of MSS, TS, WinScale and Signatures are |
1823 | * all present, we have just 2 bytes left for the SACK |
1824 | * permitted option, which is just enough. |
1825 | */ |
1826 | /* |
1827 | * If this is the first SYN of connection (not a SYN |
1828 | * ACK), include SACK permitted option. If this is a |
1829 | * SYN ACK, include SACK permitted option if peer has |
1830 | * already done so. This is only for active connect, |
1831 | * since the syncache takes care of the passive connect. |
1832 | */ |
1833 | if ((flags & TH_SYN) && |
1834 | (!(flags & TH_ACK) || (tp->t_flags & TF_SACK_PERMIT))) { |
1835 | u_char *bp; |
1836 | bp = (u_char *)opt + optlen; |
1837 | |
1838 | *bp++ = TCPOPT_SACK_PERMITTED; |
1839 | *bp++ = TCPOLEN_SACK_PERMITTED; |
1840 | optlen += TCPOLEN_SACK_PERMITTED; |
1841 | } |
1842 | } |
1843 | #if MPTCP |
1844 | if (so->so_flags & SOF_MP_SUBFLOW) { |
1845 | /* |
1846 | * Its important to piggyback acks with data as ack only packets |
1847 | * may get lost and data packets that don't send Data ACKs |
1848 | * still advance the subflow level ACK and therefore make it |
1849 | * hard for the remote end to recover in low cwnd situations. |
1850 | */ |
1851 | if (len != 0) { |
1852 | tp->t_mpflags |= (TMPF_SEND_DSN | |
1853 | TMPF_MPTCP_ACKNOW); |
1854 | } else { |
1855 | tp->t_mpflags |= TMPF_MPTCP_ACKNOW; |
1856 | } |
1857 | optlen = mptcp_setup_opts(tp, off, opt: &opt[0], optlen, flags, |
1858 | len, p_mptcp_acknow: &mptcp_acknow, do_not_compress: &do_not_compress); |
1859 | tp->t_mpflags &= ~TMPF_SEND_DSN; |
1860 | } |
1861 | #endif /* MPTCP */ |
1862 | |
1863 | if (tfo_enabled(tp) && !(tp->t_flags & TF_NOOPT) && |
1864 | (flags & (TH_SYN | TH_ACK)) == TH_SYN) { |
1865 | optlen += tcp_tfo_write_cookie(tp, optlen, len, opt); |
1866 | } |
1867 | |
1868 | if (tfo_enabled(tp) && |
1869 | (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) && |
1870 | (tp->t_tfo_flags & TFO_F_OFFER_COOKIE)) { |
1871 | optlen += tcp_tfo_write_cookie_rep(tp, optlen, opt); |
1872 | } |
1873 | |
1874 | if (SACK_ENABLED(tp) && ((tp->t_flags & TF_NOOPT) == 0)) { |
1875 | /* |
1876 | * Send SACKs if necessary. This should be the last |
1877 | * option processed. Only as many SACKs are sent as |
1878 | * are permitted by the maximum options size. |
1879 | * |
1880 | * In general, SACK blocks consume 8*n+2 bytes. |
1881 | * So a full size SACK blocks option is 34 bytes |
1882 | * (to generate 4 SACK blocks). At a minimum, |
1883 | * we need 10 bytes (to generate 1 SACK block). |
1884 | * If TCP Timestamps (12 bytes) and TCP Signatures |
1885 | * (18 bytes) are both present, we'll just have |
1886 | * 10 bytes for SACK options 40 - (12 + 18). |
1887 | */ |
1888 | if (TCPS_HAVEESTABLISHED(tp->t_state) && |
1889 | (tp->t_flags & TF_SACK_PERMIT) && |
1890 | (tp->rcv_numsacks > 0 || TCP_SEND_DSACK_OPT(tp)) && |
1891 | MAX_TCPOPTLEN - optlen >= TCPOLEN_SACK + 2) { |
1892 | unsigned int sackoptlen = 0; |
1893 | int nsack, padlen; |
1894 | u_char *bp = (u_char *)opt + optlen; |
1895 | u_int32_t *lp; |
1896 | |
1897 | nsack = (MAX_TCPOPTLEN - optlen - 2) / TCPOLEN_SACK; |
1898 | nsack = min(a: nsack, b: (tp->rcv_numsacks + |
1899 | (TCP_SEND_DSACK_OPT(tp) ? 1 : 0))); |
1900 | sackoptlen = (2 + nsack * TCPOLEN_SACK); |
1901 | VERIFY(sackoptlen < UINT8_MAX); |
1902 | |
1903 | /* |
1904 | * First we need to pad options so that the |
1905 | * SACK blocks can start at a 4-byte boundary |
1906 | * (sack option and length are at a 2 byte offset). |
1907 | */ |
1908 | padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4; |
1909 | optlen += padlen; |
1910 | while (padlen-- > 0) { |
1911 | *bp++ = TCPOPT_NOP; |
1912 | } |
1913 | |
1914 | tcpstat.tcps_sack_send_blocks++; |
1915 | *bp++ = TCPOPT_SACK; |
1916 | *bp++ = (uint8_t)sackoptlen; |
1917 | lp = (u_int32_t *)(void *)bp; |
1918 | |
1919 | /* |
1920 | * First block of SACK option should represent |
1921 | * DSACK. Prefer to send SACK information if there |
1922 | * is space for only one SACK block. This will |
1923 | * allow for faster recovery. |
1924 | */ |
1925 | if (TCP_SEND_DSACK_OPT(tp) && nsack > 0 && |
1926 | (tp->rcv_numsacks == 0 || nsack > 1)) { |
1927 | *lp++ = htonl(tp->t_dsack_lseq); |
1928 | *lp++ = htonl(tp->t_dsack_rseq); |
1929 | tcpstat.tcps_dsack_sent++; |
1930 | tp->t_dsack_sent++; |
1931 | nsack--; |
1932 | } |
1933 | VERIFY(nsack == 0 || tp->rcv_numsacks >= nsack); |
1934 | for (i = 0; i < nsack; i++) { |
1935 | struct sackblk sack = tp->sackblks[i]; |
1936 | *lp++ = htonl(sack.start); |
1937 | *lp++ = htonl(sack.end); |
1938 | } |
1939 | optlen += sackoptlen; |
1940 | |
1941 | /* Make sure we didn't write too much */ |
1942 | VERIFY((u_char *)lp - opt <= MAX_TCPOPTLEN); |
1943 | } |
1944 | } |
1945 | |
1946 | /* |
1947 | * AccECN option - after SACK |
1948 | * Don't send on <SYN>, |
1949 | * send only on <SYN,ACK> before ACCECN is negotiated or |
1950 | * when doing an AccECN session. Don't send AccECN option |
1951 | * if retransmitting a SYN-ACK or a data segment |
1952 | */ |
1953 | if ((TCP_ACC_ECN_ON(tp) || |
1954 | (TCP_ACC_ECN_ENABLED(tp) && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK))) |
1955 | && ((tp->ecn_flags & TE_RETRY_WITHOUT_ACO) == 0)) { |
1956 | uint32_t *lp = (uint32_t *)(void *)(opt + optlen); |
1957 | /* lp will become outdated after options are added */ |
1958 | tcp_add_accecn_option(tp, flags, lp, optlen: (uint8_t *)&optlen); |
1959 | } |
1960 | /* Pad TCP options to a 4 byte boundary */ |
1961 | if (optlen < MAX_TCPOPTLEN && (optlen % sizeof(u_int32_t))) { |
1962 | int pad = sizeof(u_int32_t) - (optlen % sizeof(u_int32_t)); |
1963 | u_char *bp = (u_char *)opt + optlen; |
1964 | |
1965 | optlen += pad; |
1966 | while (pad) { |
1967 | *bp++ = TCPOPT_EOL; |
1968 | pad--; |
1969 | } |
1970 | } |
1971 | |
1972 | /* |
1973 | * For Accurate ECN, send ACE flag based on r.cep, if |
1974 | * We have completed handshake and are in ESTABLISHED state, and |
1975 | * This is not the final ACK of 3WHS. |
1976 | */ |
1977 | if (TCP_ACC_ECN_ON(tp) && TCPS_HAVEESTABLISHED(tp->t_state) && |
1978 | (tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) == 0) { |
1979 | uint8_t ace = tp->t_rcv_ce_packets & TCP_ACE_MASK; |
1980 | if (ace & 0x01) { |
1981 | flags |= TH_ECE; |
1982 | } else { |
1983 | flags &= ~TH_ECE; |
1984 | } |
1985 | if (ace & 0x02) { |
1986 | flags |= TH_CWR; |
1987 | } else { |
1988 | flags &= ~TH_CWR; |
1989 | } |
1990 | if (ace & 0x04) { |
1991 | flags |= TH_AE; |
1992 | } else { |
1993 | flags &= ~TH_AE; |
1994 | } |
1995 | } |
1996 | |
1997 | /* |
1998 | * RFC 3168 states that: |
1999 | * - If you ever sent an ECN-setup SYN/SYN-ACK you must be prepared |
2000 | * to handle the TCP ECE flag, even if you also later send a |
2001 | * non-ECN-setup SYN/SYN-ACK. |
2002 | * - If you ever send a non-ECN-setup SYN/SYN-ACK, you must not set |
2003 | * the ip ECT flag. |
2004 | * |
2005 | * It is not clear how the ECE flag would ever be set if you never |
2006 | * set the IP ECT flag on outbound packets. All the same, we use |
2007 | * the TE_SETUPSENT to indicate that we have committed to handling |
2008 | * the TCP ECE flag correctly. We use the TE_SENDIPECT to indicate |
2009 | * whether or not we should set the IP ECT flag on outbound packet |
2010 | * |
2011 | * For a SYN-ACK, send an ECN setup SYN-ACK |
2012 | * |
2013 | * Below we send ECN for three different handhshake states: |
2014 | * 1. Server received SYN and is sending a SYN-ACK (state->TCPS_SYN_RECEIVED) |
2015 | * - both classic and Accurate ECN have special encoding |
2016 | * 2. Client is sending SYN packet (state->SYN_SENT) |
2017 | * - both classic and Accurate ECN have special encoding |
2018 | * 3. Client is sending final ACK of 3WHS (state->ESTABLISHED) |
2019 | * - Only Accurate ECN has special encoding |
2020 | */ |
2021 | if ((flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK) && |
2022 | (tp->ecn_flags & TE_ENABLE_ECN)) { |
2023 | /* Server received either legacy or Accurate ECN setup SYN */ |
2024 | if (tp->ecn_flags & (TE_SETUPRECEIVED | TE_ACE_SETUPRECEIVED)) { |
2025 | if (tcp_send_ecn_flags_on_syn(tp)) { |
2026 | if (TCP_ACC_ECN_ENABLED(tp) && (tp->ecn_flags & TE_ACE_SETUPRECEIVED)) { |
2027 | /* |
2028 | * Accurate ECN mode is on. Initialize packet and byte counters |
2029 | * for the server sending SYN-ACK. Although s_cep will be initialized |
2030 | * during input processing of ACK of SYN-ACK, initialize here as well |
2031 | * in case ACK gets lost. |
2032 | * |
2033 | * Non-zero initial values are used to |
2034 | * support a stateless handshake (see |
2035 | * Section 5.1 of AccECN draft) and to be |
2036 | * distinct from cases where the fields |
2037 | * are incorrectly zeroed. |
2038 | */ |
2039 | tp->t_rcv_ce_packets = 5; |
2040 | tp->t_snd_ce_packets = 5; |
2041 | |
2042 | /* Initialize CE byte counter to 0 */ |
2043 | tp->t_rcv_ce_bytes = tp->t_snd_ce_bytes = 0; |
2044 | |
2045 | if (tp->ecn_flags & TE_ACE_SETUP_NON_ECT) { |
2046 | tp->t_prev_ace_flags = TH_CWR; |
2047 | flags |= tp->t_prev_ace_flags; |
2048 | /* Remove the setup flag as it is also used for final ACK */ |
2049 | tp->ecn_flags &= ~TE_ACE_SETUP_NON_ECT; |
2050 | tcpstat.tcps_ecn_ace_syn_not_ect++; |
2051 | } else if (tp->ecn_flags & TE_ACE_SETUP_ECT1) { |
2052 | tp->t_prev_ace_flags = (TH_CWR | TH_ECE); |
2053 | flags |= tp->t_prev_ace_flags; |
2054 | tp->ecn_flags &= ~TE_ACE_SETUP_ECT1; |
2055 | tcpstat.tcps_ecn_ace_syn_ect1++; |
2056 | } else if (tp->ecn_flags & TE_ACE_SETUP_ECT0) { |
2057 | tp->t_prev_ace_flags = TH_AE; |
2058 | flags |= tp->t_prev_ace_flags; |
2059 | tp->ecn_flags &= ~TE_ACE_SETUP_ECT0; |
2060 | tcpstat.tcps_ecn_ace_syn_ect0++; |
2061 | } else if (tp->ecn_flags & TE_ACE_SETUP_CE) { |
2062 | tp->t_prev_ace_flags = (TH_AE | TH_CWR); |
2063 | flags |= tp->t_prev_ace_flags; |
2064 | tp->ecn_flags &= ~TE_ACE_SETUP_CE; |
2065 | /* |
2066 | * Receive counter is updated on |
2067 | * all acceptable packets except |
2068 | * CE on SYN packets (SYN=1, ACK=0) |
2069 | */ |
2070 | tcpstat.tcps_ecn_ace_syn_ce++; |
2071 | } else { |
2072 | if (tp->t_prev_ace_flags != 0) { |
2073 | /* Set the flags for retransmitted SYN-ACK same as the previous one */ |
2074 | flags |= tp->t_prev_ace_flags; |
2075 | } else { |
2076 | /* We shouldn't come here */ |
2077 | panic("ECN flags (0x%x) not set correctly" , tp->ecn_flags); |
2078 | } |
2079 | } |
2080 | /* |
2081 | * We are not yet committing to send IP ECT packets when |
2082 | * Accurate ECN mode is on |
2083 | */ |
2084 | tp->ecn_flags |= (TE_ACE_SETUPSENT); |
2085 | } else if (tp->ecn_flags & TE_SETUPRECEIVED) { |
2086 | /* |
2087 | * Setting TH_ECE makes this an ECN-setup |
2088 | * SYN-ACK |
2089 | */ |
2090 | flags |= TH_ECE; |
2091 | /* |
2092 | * Record that we sent the ECN-setup and |
2093 | * default to setting IP ECT. |
2094 | */ |
2095 | tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT); |
2096 | } |
2097 | tcpstat.tcps_ecn_server_setup++; |
2098 | tcpstat.tcps_ecn_server_success++; |
2099 | } else { |
2100 | /* |
2101 | * For classic ECN, we sent an ECN-setup SYN-ACK but it was |
2102 | * dropped. Fallback to non-ECN-setup |
2103 | * SYN-ACK and clear flag to indicate that |
2104 | * we should not send data with IP ECT set |
2105 | * |
2106 | * Pretend we didn't receive an |
2107 | * ECN-setup SYN. |
2108 | * |
2109 | * We already incremented the counter |
2110 | * assuming that the ECN setup will |
2111 | * succeed. Decrementing here |
2112 | * tcps_ecn_server_success to correct it. |
2113 | * |
2114 | * For Accurate ECN, we don't yet remove TE_ACE_SETUPRECEIVED |
2115 | * as the client might have received Accurate ECN SYN-ACK. |
2116 | * We decide Accurate ECN's state on processing last ACK from the client. |
2117 | */ |
2118 | if (tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) { |
2119 | tcpstat.tcps_ecn_lost_synack++; |
2120 | tcpstat.tcps_ecn_server_success--; |
2121 | tp->ecn_flags |= TE_LOST_SYNACK; |
2122 | } |
2123 | |
2124 | tp->ecn_flags &= |
2125 | ~(TE_SETUPRECEIVED | TE_SENDIPECT | |
2126 | TE_SENDCWR); |
2127 | } |
2128 | } |
2129 | } else if ((flags & (TH_SYN | TH_ACK)) == TH_SYN && |
2130 | (tp->ecn_flags & TE_ENABLE_ECN)) { |
2131 | if (tcp_send_ecn_flags_on_syn(tp)) { |
2132 | if (TCP_ACC_ECN_ENABLED(tp)) { |
2133 | /* We are negotiating AccECN in SYN */ |
2134 | flags |= TH_ACE; |
2135 | /* |
2136 | * For AccECN, we only set the ECN-setup sent |
2137 | * flag as we are not committing to set ECT yet. |
2138 | */ |
2139 | tp->ecn_flags |= (TE_ACE_SETUPSENT); |
2140 | } else { |
2141 | /* |
2142 | * Setting TH_ECE and TH_CWR makes this an |
2143 | * ECN-setup SYN |
2144 | */ |
2145 | flags |= (TH_ECE | TH_CWR); |
2146 | /* |
2147 | * Record that we sent the ECN-setup and default to |
2148 | * setting IP ECT. |
2149 | */ |
2150 | tp->ecn_flags |= (TE_SETUPSENT | TE_SENDIPECT); |
2151 | } |
2152 | tcpstat.tcps_ecn_client_setup++; |
2153 | tp->ecn_flags |= TE_CLIENT_SETUP; |
2154 | } else { |
2155 | /* |
2156 | * We sent an ECN-setup SYN but it was dropped. |
2157 | * Fall back to non-ECN and clear flag indicating |
2158 | * we should send data with IP ECT set. |
2159 | */ |
2160 | if (tp->ecn_flags & (TE_SETUPSENT | TE_ACE_SETUPSENT)) { |
2161 | tcpstat.tcps_ecn_lost_syn++; |
2162 | tp->ecn_flags |= TE_LOST_SYN; |
2163 | } |
2164 | tp->ecn_flags &= ~TE_SENDIPECT; |
2165 | } |
2166 | } else if (TCP_ACC_ECN_ON(tp) && (tp->ecn_flags & TE_ACE_FINAL_ACK_3WHS) && |
2167 | len == 0 && (flags & (TH_FLAGS_ALL)) == TH_ACK) { |
2168 | /* |
2169 | * Client has processed SYN-ACK and moved to ESTABLISHED. |
2170 | * This is the final ACK of 3WHS. If ACC_ECN has been negotiated, |
2171 | * then send the handshake encoding as per Table 3 of Accurate ECN draft. |
2172 | * We are clearing the ACE flags just in case if they were set before. |
2173 | * TODO: if client has to carry data in the 3WHS ACK, then we need to send a pure ACK first |
2174 | */ |
2175 | flags &= ~(TH_AE | TH_CWR | TH_ECE); |
2176 | if (tp->ecn_flags & TE_ACE_SETUP_NON_ECT) { |
2177 | flags |= TH_CWR; |
2178 | tp->ecn_flags &= ~TE_ACE_SETUP_NON_ECT; |
2179 | } else if (tp->ecn_flags & TE_ACE_SETUP_ECT1) { |
2180 | flags |= (TH_CWR | TH_ECE); |
2181 | tp->ecn_flags &= ~TE_ACE_SETUP_ECT1; |
2182 | } else if (tp->ecn_flags & TE_ACE_SETUP_ECT0) { |
2183 | flags |= TH_AE; |
2184 | tp->ecn_flags &= ~TE_ACE_SETUP_ECT0; |
2185 | } else if (tp->ecn_flags & TE_ACE_SETUP_CE) { |
2186 | flags |= (TH_AE | TH_CWR); |
2187 | tp->ecn_flags &= ~TE_ACE_SETUP_CE; |
2188 | } |
2189 | tp->ecn_flags &= ~(TE_ACE_FINAL_ACK_3WHS); |
2190 | } |
2191 | |
2192 | /* |
2193 | * Check if we should set the TCP CWR flag. |
2194 | * CWR flag is sent when we reduced the congestion window because |
2195 | * we received a TCP ECE or we performed a fast retransmit. We |
2196 | * never set the CWR flag on retransmitted packets. We only set |
2197 | * the CWR flag on data packets. Pure acks don't have this set. |
2198 | */ |
2199 | if ((tp->ecn_flags & TE_SENDCWR) != 0 && len != 0 && |
2200 | !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) { |
2201 | flags |= TH_CWR; |
2202 | tp->ecn_flags &= ~TE_SENDCWR; |
2203 | } |
2204 | |
2205 | /* |
2206 | * Check if we should set the TCP ECE flag. |
2207 | */ |
2208 | if ((tp->ecn_flags & TE_SENDECE) != 0 && len == 0) { |
2209 | flags |= TH_ECE; |
2210 | tcpstat.tcps_ecn_sent_ece++; |
2211 | } |
2212 | |
2213 | hdrlen += optlen; |
2214 | |
2215 | /* Reset DSACK sequence numbers */ |
2216 | tp->t_dsack_lseq = 0; |
2217 | tp->t_dsack_rseq = 0; |
2218 | |
2219 | if (isipv6) { |
2220 | ipoptlen = ip6_optlen(inp); |
2221 | } else { |
2222 | if (tp_inp_options) { |
2223 | ipoptlen = tp_inp_options->m_len - |
2224 | offsetof(struct ipoption, ipopt_list); |
2225 | } else { |
2226 | ipoptlen = 0; |
2227 | } |
2228 | } |
2229 | #if IPSEC |
2230 | ipoptlen += ipsec_optlen; |
2231 | #endif |
2232 | |
2233 | /* |
2234 | * Adjust data length if insertion of options will |
2235 | * bump the packet length beyond the t_maxopd length. |
2236 | * Clear the FIN bit because we cut off the tail of |
2237 | * the segment. |
2238 | * |
2239 | * When doing TSO limit a burst to TCP_MAXWIN minus the |
2240 | * IP, TCP and Options length to keep ip->ip_len from |
2241 | * overflowing. Prevent the last segment from being |
2242 | * fractional thus making them all equal sized and set |
2243 | * the flag to continue sending. TSO is disabled when |
2244 | * IP options or IPSEC are present. |
2245 | */ |
2246 | if (len + optlen + ipoptlen > tp->t_maxopd) { |
2247 | /* |
2248 | * If there is still more to send, |
2249 | * don't close the connection. |
2250 | */ |
2251 | flags &= ~TH_FIN; |
2252 | if (tso) { |
2253 | int32_t tso_maxlen; |
2254 | |
2255 | tso_maxlen = tp->tso_max_segment_size ? |
2256 | tp->tso_max_segment_size : TCP_MAXWIN; |
2257 | |
2258 | /* hdrlen includes optlen */ |
2259 | if (len > tso_maxlen - hdrlen) { |
2260 | len = tso_maxlen - hdrlen; |
2261 | sendalot = 1; |
2262 | } else if (tp->t_flags & TF_NEEDFIN) { |
2263 | sendalot = 1; |
2264 | } |
2265 | |
2266 | if (len % (tp->t_maxopd - optlen) != 0) { |
2267 | len = len - (len % (tp->t_maxopd - optlen)); |
2268 | sendalot = 1; |
2269 | } |
2270 | } else { |
2271 | len = tp->t_maxopd - optlen - ipoptlen; |
2272 | sendalot = 1; |
2273 | } |
2274 | } |
2275 | |
2276 | if (max_linkhdr + hdrlen > MCLBYTES) { |
2277 | panic("tcphdr too big" ); |
2278 | } |
2279 | |
2280 | /* Check if there is enough data in the send socket |
2281 | * buffer to start measuring bandwidth |
2282 | */ |
2283 | if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 && |
2284 | (tp->t_bwmeas != NULL) && |
2285 | (tp->t_flagsext & TF_BWMEAS_INPROGRESS) == 0) { |
2286 | tp->t_bwmeas->bw_size = min(a: min( |
2287 | a: (so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)), |
2288 | b: tp->snd_cwnd), b: tp->snd_wnd); |
2289 | if (tp->t_bwmeas->bw_minsize > 0 && |
2290 | tp->t_bwmeas->bw_size < tp->t_bwmeas->bw_minsize) { |
2291 | tp->t_bwmeas->bw_size = 0; |
2292 | } |
2293 | if (tp->t_bwmeas->bw_maxsize > 0) { |
2294 | tp->t_bwmeas->bw_size = min(a: tp->t_bwmeas->bw_size, |
2295 | b: tp->t_bwmeas->bw_maxsize); |
2296 | } |
2297 | if (tp->t_bwmeas->bw_size > 0) { |
2298 | tp->t_flagsext |= TF_BWMEAS_INPROGRESS; |
2299 | tp->t_bwmeas->bw_start = tp->snd_max; |
2300 | tp->t_bwmeas->bw_ts = tcp_now; |
2301 | } |
2302 | } |
2303 | |
2304 | VERIFY(inp->inp_flowhash != 0); |
2305 | /* |
2306 | * Grab a header mbuf, attaching a copy of data to |
2307 | * be transmitted, and initialize the header from |
2308 | * the template for sends on this connection. |
2309 | */ |
2310 | if (len) { |
2311 | /* Remember what the last head-of-line packet-size was */ |
2312 | if (tp->t_pmtud_lastseg_size == 0 && tp->snd_nxt == tp->snd_una) { |
2313 | ASSERT(len + optlen + ipoptlen <= IP_MAXPACKET); |
2314 | tp->t_pmtud_lastseg_size = (uint16_t)(len + optlen + ipoptlen); |
2315 | } |
2316 | if ((tp->t_flagsext & TF_FORCE) && len == 1) { |
2317 | tcpstat.tcps_sndprobe++; |
2318 | } else if (SEQ_LT(tp->snd_nxt, tp->snd_max) || sack_rxmit) { |
2319 | tcpstat.tcps_sndrexmitpack++; |
2320 | tcpstat.tcps_sndrexmitbyte += len; |
2321 | if (nstat_collect) { |
2322 | nstat_route_tx(rte: inp->inp_route.ro_rt, packets: 1, |
2323 | bytes: len, flags: NSTAT_TX_FLAG_RETRANSMIT); |
2324 | INP_ADD_STAT(inp, cell, wifi, wired, |
2325 | txpackets, 1); |
2326 | INP_ADD_STAT(inp, cell, wifi, wired, |
2327 | txbytes, len); |
2328 | tp->t_stat.txretransmitbytes += len; |
2329 | tp->t_stat.rxmitpkts++; |
2330 | } |
2331 | if (tp->ecn_flags & TE_SENDIPECT) { |
2332 | tp->t_ecn_capable_packets_lost++; |
2333 | } |
2334 | } else { |
2335 | tcpstat.tcps_sndpack++; |
2336 | tcpstat.tcps_sndbyte += len; |
2337 | |
2338 | if (nstat_collect) { |
2339 | INP_ADD_STAT(inp, cell, wifi, wired, |
2340 | txpackets, 1); |
2341 | INP_ADD_STAT(inp, cell, wifi, wired, |
2342 | txbytes, len); |
2343 | } |
2344 | if (tp->ecn_flags & TE_SENDIPECT) { |
2345 | tp->t_ecn_capable_packets_sent++; |
2346 | } |
2347 | inp_decr_sndbytes_unsent(so, len); |
2348 | } |
2349 | inp_set_activity_bitmap(inp); |
2350 | #if MPTCP |
2351 | if (tp->t_mpflags & TMPF_MPTCP_TRUE) { |
2352 | tcpstat.tcps_mp_sndpacks++; |
2353 | tcpstat.tcps_mp_sndbytes += len; |
2354 | } |
2355 | #endif /* MPTCP */ |
2356 | /* |
2357 | * try to use the new interface that allocates all |
2358 | * the necessary mbuf hdrs under 1 mbuf lock and |
2359 | * avoids rescanning the socket mbuf list if |
2360 | * certain conditions are met. This routine can't |
2361 | * be used in the following cases... |
2362 | * 1) the protocol headers exceed the capacity of |
2363 | * of a single mbuf header's data area (no cluster attached) |
2364 | * 2) the length of the data being transmitted plus |
2365 | * the protocol headers fits into a single mbuf header's |
2366 | * data area (no cluster attached) |
2367 | */ |
2368 | m = NULL; |
2369 | |
2370 | /* minimum length we are going to allocate */ |
2371 | allocated_len = MHLEN; |
2372 | if (MHLEN < hdrlen + max_linkhdr) { |
2373 | MGETHDR(m, M_DONTWAIT, MT_HEADER); |
2374 | if (m == NULL) { |
2375 | error = ENOBUFS; |
2376 | goto out; |
2377 | } |
2378 | MCLGET(m, M_DONTWAIT); |
2379 | if ((m->m_flags & M_EXT) == 0) { |
2380 | m_freem(m); |
2381 | error = ENOBUFS; |
2382 | goto out; |
2383 | } |
2384 | m->m_data += max_linkhdr; |
2385 | m->m_len = hdrlen; |
2386 | allocated_len = MCLBYTES; |
2387 | } |
2388 | if (len <= allocated_len - hdrlen - max_linkhdr) { |
2389 | if (m == NULL) { |
2390 | VERIFY(allocated_len <= MHLEN); |
2391 | MGETHDR(m, M_DONTWAIT, MT_HEADER); |
2392 | if (m == NULL) { |
2393 | error = ENOBUFS; |
2394 | goto out; |
2395 | } |
2396 | m->m_data += max_linkhdr; |
2397 | m->m_len = hdrlen; |
2398 | } |
2399 | /* makes sure we still have data left to be sent at this point */ |
2400 | if (so->so_snd.sb_mb == NULL || off < 0) { |
2401 | if (m != NULL) { |
2402 | m_freem(m); |
2403 | } |
2404 | error = 0; /* should we return an error? */ |
2405 | goto out; |
2406 | } |
2407 | m_copydata(so->so_snd.sb_mb, off, (int) len, |
2408 | mtod(m, caddr_t) + hdrlen); |
2409 | m->m_len += len; |
2410 | } else { |
2411 | uint32_t copymode; |
2412 | /* |
2413 | * Retain packet header metadata at the socket |
2414 | * buffer if this is is an MPTCP subflow, |
2415 | * otherwise move it. |
2416 | */ |
2417 | copymode = M_COPYM_MOVE_HDR; |
2418 | #if MPTCP |
2419 | if (so->so_flags & SOF_MP_SUBFLOW) { |
2420 | copymode = M_COPYM_NOOP_HDR; |
2421 | } |
2422 | #endif /* MPTCP */ |
2423 | if (m != NULL) { |
2424 | if (so->so_snd.sb_flags & SB_SENDHEAD) { |
2425 | VERIFY(so->so_snd.sb_flags & SB_SENDHEAD); |
2426 | VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc); |
2427 | |
2428 | m->m_next = m_copym_mode(so->so_snd.sb_mb, |
2429 | off, (int)len, M_DONTWAIT, |
2430 | &so->so_snd.sb_sendhead, |
2431 | &so->so_snd.sb_sendoff, copymode); |
2432 | |
2433 | VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc); |
2434 | } else { |
2435 | m->m_next = m_copym_mode(so->so_snd.sb_mb, |
2436 | off, (int)len, M_DONTWAIT, |
2437 | NULL, NULL, copymode); |
2438 | } |
2439 | if (m->m_next == NULL) { |
2440 | (void) m_free(m); |
2441 | error = ENOBUFS; |
2442 | goto out; |
2443 | } |
2444 | } else { |
2445 | /* |
2446 | * make sure we still have data left |
2447 | * to be sent at this point |
2448 | */ |
2449 | if (so->so_snd.sb_mb == NULL) { |
2450 | error = 0; /* should we return an error? */ |
2451 | goto out; |
2452 | } |
2453 | |
2454 | /* |
2455 | * m_copym_with_hdrs will always return the |
2456 | * last mbuf pointer and the offset into it that |
2457 | * it acted on to fullfill the current request, |
2458 | * whether a valid 'hint' was passed in or not. |
2459 | */ |
2460 | if (so->so_snd.sb_flags & SB_SENDHEAD) { |
2461 | VERIFY(so->so_snd.sb_flags & SB_SENDHEAD); |
2462 | VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc); |
2463 | |
2464 | m = m_copym_with_hdrs(so->so_snd.sb_mb, |
2465 | off, len, M_DONTWAIT, &so->so_snd.sb_sendhead, |
2466 | &so->so_snd.sb_sendoff, copymode); |
2467 | |
2468 | VERIFY(so->so_snd.sb_sendoff <= so->so_snd.sb_cc); |
2469 | } else { |
2470 | m = m_copym_with_hdrs(so->so_snd.sb_mb, |
2471 | off, len, M_DONTWAIT, NULL, |
2472 | NULL, copymode); |
2473 | } |
2474 | if (m == NULL) { |
2475 | error = ENOBUFS; |
2476 | goto out; |
2477 | } |
2478 | m->m_data += max_linkhdr; |
2479 | m->m_len = hdrlen; |
2480 | } |
2481 | } |
2482 | /* |
2483 | * If we're sending everything we've got, set PUSH. |
2484 | * (This will keep happy those implementations which only |
2485 | * give data to the user when a buffer fills or |
2486 | * a PUSH comes in.) |
2487 | * |
2488 | * On SYN-segments we should not add the PUSH-flag. |
2489 | */ |
2490 | if (off + len == so->so_snd.sb_cc && !(flags & TH_SYN)) { |
2491 | flags |= TH_PUSH; |
2492 | } |
2493 | } else { |
2494 | if (tp->t_flags & TF_ACKNOW) { |
2495 | tcpstat.tcps_sndacks++; |
2496 | } else if (flags & (TH_SYN | TH_FIN | TH_RST)) { |
2497 | tcpstat.tcps_sndctrl++; |
2498 | } else if (SEQ_GT(tp->snd_up, tp->snd_una)) { |
2499 | tcpstat.tcps_sndurg++; |
2500 | } else { |
2501 | tcpstat.tcps_sndwinup++; |
2502 | } |
2503 | |
2504 | MGETHDR(m, M_DONTWAIT, MT_HEADER); /* MAC-OK */ |
2505 | if (m == NULL) { |
2506 | error = ENOBUFS; |
2507 | goto out; |
2508 | } |
2509 | if (MHLEN < (hdrlen + max_linkhdr)) { |
2510 | MCLGET(m, M_DONTWAIT); |
2511 | if ((m->m_flags & M_EXT) == 0) { |
2512 | m_freem(m); |
2513 | error = ENOBUFS; |
2514 | goto out; |
2515 | } |
2516 | } |
2517 | m->m_data += max_linkhdr; |
2518 | m->m_len = hdrlen; |
2519 | } |
2520 | m->m_pkthdr.rcvif = 0; |
2521 | m_add_crumb(m, PKT_CRUMB_TCP_OUTPUT); |
2522 | |
2523 | /* Any flag other than pure-ACK: Do not compress! */ |
2524 | if (flags & ~(TH_ACK)) { |
2525 | do_not_compress = TRUE; |
2526 | } |
2527 | |
2528 | if (tp->rcv_scale == 0) { |
2529 | do_not_compress = TRUE; |
2530 | } |
2531 | |
2532 | if (do_not_compress) { |
2533 | m->m_pkthdr.comp_gencnt = 0; |
2534 | } else { |
2535 | if (TSTMP_LT(tp->t_comp_lastinc + tcp_ack_compression_rate, tcp_now)) { |
2536 | tp->t_comp_gencnt++; |
2537 | /* 0 means no compression, thus jump this */ |
2538 | if (tp->t_comp_gencnt <= TCP_ACK_COMPRESSION_DUMMY) { |
2539 | tp->t_comp_gencnt = TCP_ACK_COMPRESSION_DUMMY + 1; |
2540 | } |
2541 | tp->t_comp_lastinc = tcp_now; |
2542 | } |
2543 | m->m_pkthdr.comp_gencnt = tp->t_comp_gencnt; |
2544 | } |
2545 | |
2546 | if (isipv6) { |
2547 | ip6 = mtod(m, struct ip6_hdr *); |
2548 | th = (struct tcphdr *)(void *)(ip6 + 1); |
2549 | tcp_fillheaders(m, tp, ip6, th); |
2550 | if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len && |
2551 | !SEQ_LT(tp->snd_nxt, tp->snd_max) && !sack_rxmit) { |
2552 | ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); |
2553 | } |
2554 | svc_flags |= PKT_SCF_IPV6; |
2555 | #if PF_ECN |
2556 | m_pftag(m)->pftag_hdr = (void *)ip6; |
2557 | m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET6; |
2558 | #endif /* PF_ECN */ |
2559 | } else { |
2560 | ip = mtod(m, struct ip *); |
2561 | th = (struct tcphdr *)(void *)(ip + 1); |
2562 | /* this picks up the pseudo header (w/o the length) */ |
2563 | tcp_fillheaders(m, tp, ip, th); |
2564 | if ((tp->ecn_flags & TE_SENDIPECT) != 0 && len && |
2565 | !SEQ_LT(tp->snd_nxt, tp->snd_max) && |
2566 | !sack_rxmit && !(flags & TH_SYN)) { |
2567 | ip->ip_tos |= IPTOS_ECN_ECT0; |
2568 | } |
2569 | #if PF_ECN |
2570 | m_pftag(m)->pftag_hdr = (void *)ip; |
2571 | m_pftag(m)->pftag_flags |= PF_TAG_HDR_INET; |
2572 | #endif /* PF_ECN */ |
2573 | } |
2574 | |
2575 | /* |
2576 | * Fill in fields, remembering maximum advertised |
2577 | * window for use in delaying messages about window sizes. |
2578 | * If resending a FIN, be sure not to use a new sequence number. |
2579 | */ |
2580 | if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) && |
2581 | tp->snd_nxt == tp->snd_max) { |
2582 | tp->snd_nxt--; |
2583 | } |
2584 | /* |
2585 | * If we are doing retransmissions, then snd_nxt will |
2586 | * not reflect the first unsent octet. For ACK only |
2587 | * packets, we do not want the sequence number of the |
2588 | * retransmitted packet, we want the sequence number |
2589 | * of the next unsent octet. So, if there is no data |
2590 | * (and no SYN or FIN), use snd_max instead of snd_nxt |
2591 | * when filling in ti_seq. But if we are in persist |
2592 | * state, snd_max might reflect one byte beyond the |
2593 | * right edge of the window, so use snd_nxt in that |
2594 | * case, since we know we aren't doing a retransmission. |
2595 | * (retransmit and persist are mutually exclusive...) |
2596 | * |
2597 | * Note the state of this retransmit segment to detect spurious |
2598 | * retransmissions. |
2599 | */ |
2600 | if (sack_rxmit == 0) { |
2601 | if (len || (flags & (TH_SYN | TH_FIN)) || |
2602 | tp->t_timer[TCPT_PERSIST]) { |
2603 | th->th_seq = htonl(tp->snd_nxt); |
2604 | if (len > 0) { |
2605 | m->m_pkthdr.tx_start_seq = tp->snd_nxt; |
2606 | m->m_pkthdr.pkt_flags |= PKTF_START_SEQ; |
2607 | } |
2608 | if (SEQ_LT(tp->snd_nxt, tp->snd_max)) { |
2609 | if (SACK_ENABLED(tp) && len > 1 && |
2610 | !(tp->t_flagsext & TF_SENT_TLPROBE)) { |
2611 | tcp_rxtseg_insert(tp, tp->snd_nxt, |
2612 | (tp->snd_nxt + len - 1)); |
2613 | } |
2614 | if (len > 0) { |
2615 | m->m_pkthdr.pkt_flags |= |
2616 | PKTF_TCP_REXMT; |
2617 | } |
2618 | } |
2619 | } else { |
2620 | th->th_seq = htonl(tp->snd_max); |
2621 | } |
2622 | } else { |
2623 | th->th_seq = htonl(p->rxmit); |
2624 | if (len > 0) { |
2625 | m->m_pkthdr.pkt_flags |= |
2626 | (PKTF_TCP_REXMT | PKTF_START_SEQ); |
2627 | m->m_pkthdr.tx_start_seq = p->rxmit; |
2628 | } |
2629 | tcp_rxtseg_insert(tp, p->rxmit, (p->rxmit + len - 1)); |
2630 | p->rxmit += len; |
2631 | tp->sackhint.sack_bytes_rexmit += len; |
2632 | } |
2633 | th->th_ack = htonl(tp->rcv_nxt); |
2634 | tp->last_ack_sent = tp->rcv_nxt; |
2635 | if (optlen) { |
2636 | bcopy(src: opt, dst: th + 1, n: optlen); |
2637 | th->th_off = (sizeof(struct tcphdr) + optlen) >> 2; |
2638 | } |
2639 | /* Separate AE from flags */ |
2640 | th->th_flags = (flags & (TH_FLAGS_ALL)); |
2641 | th->th_x2 = (flags & (TH_AE)) >> 8; |
2642 | th->th_win = htons((u_short) (recwin >> tp->rcv_scale)); |
2643 | tp->t_last_recwin = recwin; |
2644 | if (!(so->so_flags & SOF_MP_SUBFLOW)) { |
2645 | if (recwin > 0 && SEQ_LT(tp->rcv_adv, tp->rcv_nxt + recwin)) { |
2646 | tp->rcv_adv = tp->rcv_nxt + recwin; |
2647 | } |
2648 | } else { |
2649 | struct mptcb *mp_tp = tptomptp(tp); |
2650 | if (recwin > 0) { |
2651 | tp->rcv_adv = tp->rcv_nxt + recwin; |
2652 | } |
2653 | |
2654 | if (recwin > 0 && MPTCP_SEQ_LT(mp_tp->mpt_rcvadv, mp_tp->mpt_rcvnxt + recwin)) { |
2655 | mp_tp->mpt_rcvadv = mp_tp->mpt_rcvnxt + recwin; |
2656 | } |
2657 | } |
2658 | |
2659 | /* |
2660 | * Adjust the RXWIN0SENT flag - indicate that we have advertised |
2661 | * a 0 window. This may cause the remote transmitter to stall. This |
2662 | * flag tells soreceive() to disable delayed acknowledgements when |
2663 | * draining the buffer. This can occur if the receiver is attempting |
2664 | * to read more data then can be buffered prior to transmitting on |
2665 | * the connection. |
2666 | */ |
2667 | if (th->th_win == 0) { |
2668 | tp->t_flags |= TF_RXWIN0SENT; |
2669 | } else { |
2670 | tp->t_flags &= ~TF_RXWIN0SENT; |
2671 | } |
2672 | |
2673 | if (SEQ_GT(tp->snd_up, tp->snd_nxt)) { |
2674 | th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt)); |
2675 | th->th_flags |= TH_URG; |
2676 | } else { |
2677 | /* |
2678 | * If no urgent pointer to send, then we pull |
2679 | * the urgent pointer to the left edge of the send window |
2680 | * so that it doesn't drift into the send window on sequence |
2681 | * number wraparound. |
2682 | */ |
2683 | tp->snd_up = tp->snd_una; /* drag it along */ |
2684 | } |
2685 | |
2686 | /* |
2687 | * Put TCP length in extended header, and then |
2688 | * checksum extended header and data. |
2689 | */ |
2690 | m->m_pkthdr.len = hdrlen + len; /* in6_cksum() need this */ |
2691 | |
2692 | /* |
2693 | * If this is potentially the last packet on the stream, then mark |
2694 | * it in order to enable some optimizations in the underlying |
2695 | * layers |
2696 | */ |
2697 | if (tp->t_state != TCPS_ESTABLISHED && |
2698 | (tp->t_state == TCPS_CLOSING || tp->t_state == TCPS_TIME_WAIT |
2699 | || tp->t_state == TCPS_LAST_ACK || (th->th_flags & TH_RST))) { |
2700 | m->m_pkthdr.pkt_flags |= PKTF_LAST_PKT; |
2701 | } |
2702 | |
2703 | if (isipv6) { |
2704 | /* |
2705 | * ip6_plen is not need to be filled now, and will be filled |
2706 | * in ip6_output. |
2707 | */ |
2708 | m->m_pkthdr.csum_flags = CSUM_TCPIPV6; |
2709 | m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); |
2710 | if (len + optlen) { |
2711 | th->th_sum = in_addword(th->th_sum, |
2712 | htons((u_short)(optlen + len))); |
2713 | } |
2714 | } else { |
2715 | m->m_pkthdr.csum_flags = CSUM_TCP; |
2716 | m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum); |
2717 | if (len + optlen) { |
2718 | th->th_sum = in_addword(th->th_sum, |
2719 | htons((u_short)(optlen + len))); |
2720 | } |
2721 | } |
2722 | |
2723 | /* |
2724 | * Enable TSO and specify the size of the segments. |
2725 | * The TCP pseudo header checksum is always provided. |
2726 | */ |
2727 | if (tso) { |
2728 | if (isipv6) { |
2729 | m->m_pkthdr.csum_flags |= CSUM_TSO_IPV6; |
2730 | } else { |
2731 | m->m_pkthdr.csum_flags |= CSUM_TSO_IPV4; |
2732 | } |
2733 | |
2734 | m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen; |
2735 | } else { |
2736 | m->m_pkthdr.tso_segsz = 0; |
2737 | } |
2738 | |
2739 | /* |
2740 | * In transmit state, time the transmission and arrange for |
2741 | * the retransmit. In persist state, just set snd_max. |
2742 | */ |
2743 | if (!(tp->t_flagsext & TF_FORCE) |
2744 | || tp->t_timer[TCPT_PERSIST] == 0) { |
2745 | tcp_seq startseq = tp->snd_nxt; |
2746 | |
2747 | /* |
2748 | * Advance snd_nxt over sequence space of this segment. |
2749 | */ |
2750 | if (flags & (TH_SYN | TH_FIN)) { |
2751 | if (flags & TH_SYN) { |
2752 | tp->snd_nxt++; |
2753 | } |
2754 | if ((flags & TH_FIN) && |
2755 | !(tp->t_flags & TF_SENTFIN)) { |
2756 | tp->snd_nxt++; |
2757 | tp->t_flags |= TF_SENTFIN; |
2758 | } |
2759 | } |
2760 | if (sack_rxmit) { |
2761 | goto timer; |
2762 | } |
2763 | if (sack_rescue_rxt == TRUE) { |
2764 | tp->snd_nxt = old_snd_nxt; |
2765 | sack_rescue_rxt = FALSE; |
2766 | tcpstat.tcps_pto_in_recovery++; |
2767 | } else { |
2768 | tp->snd_nxt += len; |
2769 | } |
2770 | if (SEQ_GT(tp->snd_nxt, tp->snd_max)) { |
2771 | tp->snd_max = tp->snd_nxt; |
2772 | tp->t_sndtime = tcp_now; |
2773 | /* |
2774 | * Time this transmission if not a retransmission and |
2775 | * not currently timing anything. |
2776 | */ |
2777 | if (tp->t_rtttime == 0) { |
2778 | tp->t_rtttime = tcp_now; |
2779 | tp->t_rtseq = startseq; |
2780 | tcpstat.tcps_segstimed++; |
2781 | |
2782 | /* update variables related to pipe ack */ |
2783 | tp->t_pipeack_lastuna = tp->snd_una; |
2784 | } |
2785 | } |
2786 | |
2787 | /* |
2788 | * Set retransmit timer if not currently set, |
2789 | * and not doing an ack or a keep-alive probe. |
2790 | */ |
2791 | timer: |
2792 | if (tp->t_timer[TCPT_REXMT] == 0 && |
2793 | ((sack_rxmit && tp->snd_nxt != tp->snd_max) || |
2794 | tp->snd_nxt != tp->snd_una || (flags & TH_FIN))) { |
2795 | if (tp->t_timer[TCPT_PERSIST]) { |
2796 | tp->t_timer[TCPT_PERSIST] = 0; |
2797 | tp->t_persist_stop = 0; |
2798 | TCP_RESET_REXMT_STATE(tp); |
2799 | } |
2800 | tp->t_timer[TCPT_REXMT] = |
2801 | OFFSET_FROM_START(tp, tp->t_rxtcur); |
2802 | } |
2803 | |
2804 | /* |
2805 | * Set tail loss probe timeout if new data is being |
2806 | * transmitted. This will be supported only when |
2807 | * SACK option is enabled on a connection. |
2808 | * |
2809 | * Every time new data is sent PTO will get reset. |
2810 | */ |
2811 | if (tcp_enable_tlp && len != 0 && tp->t_state == TCPS_ESTABLISHED && |
2812 | SACK_ENABLED(tp) && !IN_FASTRECOVERY(tp) && |
2813 | tp->snd_nxt == tp->snd_max && |
2814 | SEQ_GT(tp->snd_nxt, tp->snd_una) && |
2815 | tp->t_rxtshift == 0 && |
2816 | (tp->t_flagsext & (TF_SENT_TLPROBE | TF_PKTS_REORDERED)) == 0) { |
2817 | uint32_t pto, srtt; |
2818 | |
2819 | if (tcp_do_better_lr) { |
2820 | srtt = tp->t_srtt >> TCP_RTT_SHIFT; |
2821 | pto = 2 * srtt; |
2822 | if ((tp->snd_max - tp->snd_una) <= tp->t_maxseg) { |
2823 | pto += tcp_delack; |
2824 | } else { |
2825 | pto += 2; |
2826 | } |
2827 | } else { |
2828 | /* |
2829 | * Using SRTT alone to set PTO can cause spurious |
2830 | * retransmissions on wireless networks where there |
2831 | * is a lot of variance in RTT. Taking variance |
2832 | * into account will avoid this. |
2833 | */ |
2834 | srtt = tp->t_srtt >> TCP_RTT_SHIFT; |
2835 | pto = ((TCP_REXMTVAL(tp)) * 3) >> 1; |
2836 | pto = max(a: 2 * srtt, b: pto); |
2837 | if ((tp->snd_max - tp->snd_una) == tp->t_maxseg) { |
2838 | pto = max(a: pto, |
2839 | b: (((3 * pto) >> 2) + tcp_delack * 2)); |
2840 | } else { |
2841 | pto = max(a: 10, b: pto); |
2842 | } |
2843 | } |
2844 | |
2845 | /* if RTO is less than PTO, choose RTO instead */ |
2846 | if (tp->t_rxtcur < pto) { |
2847 | pto = tp->t_rxtcur; |
2848 | } |
2849 | |
2850 | tp->t_timer[TCPT_PTO] = OFFSET_FROM_START(tp, pto); |
2851 | } |
2852 | } else { |
2853 | /* |
2854 | * Persist case, update snd_max but since we are in |
2855 | * persist mode (no window) we do not update snd_nxt. |
2856 | */ |
2857 | int xlen = len; |
2858 | if (flags & TH_SYN) { |
2859 | ++xlen; |
2860 | } |
2861 | if ((flags & TH_FIN) && |
2862 | !(tp->t_flags & TF_SENTFIN)) { |
2863 | ++xlen; |
2864 | tp->t_flags |= TF_SENTFIN; |
2865 | } |
2866 | if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max)) { |
2867 | tp->snd_max = tp->snd_nxt + len; |
2868 | tp->t_sndtime = tcp_now; |
2869 | } |
2870 | } |
2871 | |
2872 | #if TCPDEBUG |
2873 | /* |
2874 | * Trace. |
2875 | */ |
2876 | if (so_options & SO_DEBUG) { |
2877 | tcp_trace(TA_OUTPUT, tp->t_state, tp, mtod(m, void *), th, 0); |
2878 | } |
2879 | #endif |
2880 | |
2881 | /* |
2882 | * Fill in IP length and desired time to live and |
2883 | * send to IP level. There should be a better way |
2884 | * to handle ttl and tos; we could keep them in |
2885 | * the template, but need a way to checksum without them. |
2886 | */ |
2887 | /* |
2888 | * m->m_pkthdr.len should have been set before cksum calcuration, |
2889 | * because in6_cksum() need it. |
2890 | */ |
2891 | if (isipv6) { |
2892 | /* |
2893 | * we separately set hoplimit for every segment, since the |
2894 | * user might want to change the value via setsockopt. |
2895 | * Also, desired default hop limit might be changed via |
2896 | * Neighbor Discovery. |
2897 | */ |
2898 | ip6->ip6_hlim = in6_selecthlim(inp, inp->in6p_route.ro_rt ? |
2899 | inp->in6p_route.ro_rt->rt_ifp : NULL); |
2900 | |
2901 | /* Don't set ECT bit if requested by an app */ |
2902 | |
2903 | /* Set ECN bits for testing purposes */ |
2904 | if (tp->ecn_flags & TE_FORCE_ECT1) { |
2905 | ip6->ip6_flow |= htonl(IPTOS_ECN_ECT1 << 20); |
2906 | } else if (tp->ecn_flags & TE_FORCE_ECT0) { |
2907 | ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20); |
2908 | } |
2909 | |
2910 | KERNEL_DEBUG(DBG_LAYER_BEG, |
2911 | ((inp->inp_fport << 16) | inp->inp_lport), |
2912 | (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) | |
2913 | (inp->in6p_faddr.s6_addr16[0] & 0xffff)), |
2914 | sendalot, 0, 0); |
2915 | } else { |
2916 | ASSERT(m->m_pkthdr.len <= IP_MAXPACKET); |
2917 | ip->ip_len = (u_short)m->m_pkthdr.len; |
2918 | ip->ip_ttl = inp->inp_ip_ttl; /* XXX */ |
2919 | |
2920 | /* Don't set ECN bit if requested by an app */ |
2921 | ip->ip_tos |= (inp->inp_ip_tos & ~IPTOS_ECN_MASK); |
2922 | |
2923 | /* Set ECN bits for testing purposes */ |
2924 | if (tp->ecn_flags & TE_FORCE_ECT1) { |
2925 | ip->ip_tos |= IPTOS_ECN_ECT1; |
2926 | } else if (tp->ecn_flags & TE_FORCE_ECT0) { |
2927 | ip->ip_tos |= IPTOS_ECN_ECT0; |
2928 | } |
2929 | |
2930 | KERNEL_DEBUG(DBG_LAYER_BEG, |
2931 | ((inp->inp_fport << 16) | inp->inp_lport), |
2932 | (((inp->inp_laddr.s_addr & 0xffff) << 16) | |
2933 | (inp->inp_faddr.s_addr & 0xffff)), 0, 0, 0); |
2934 | } |
2935 | |
2936 | /* |
2937 | * See if we should do MTU discovery. |
2938 | * Look at the flag updated on the following criterias: |
2939 | * 1) Path MTU discovery is authorized by the sysctl |
2940 | * 2) The route isn't set yet (unlikely but could happen) |
2941 | * 3) The route is up |
2942 | * 4) the MTU is not locked (if it is, then discovery has been |
2943 | * disabled for that route) |
2944 | */ |
2945 | if (!isipv6) { |
2946 | if (path_mtu_discovery && (tp->t_flags & TF_PMTUD)) { |
2947 | ip->ip_off |= IP_DF; |
2948 | } |
2949 | } |
2950 | |
2951 | #if NECP |
2952 | { |
2953 | necp_kernel_policy_id policy_id; |
2954 | necp_kernel_policy_id skip_policy_id; |
2955 | u_int32_t route_rule_id; |
2956 | u_int32_t pass_flags; |
2957 | if (!necp_socket_is_allowed_to_send_recv(inp, NULL, pf_tag: 0, return_policy_id: &policy_id, return_route_rule_id: &route_rule_id, return_skip_policy_id: &skip_policy_id, return_pass_flags: &pass_flags)) { |
2958 | TCP_LOG_DROP_NECP(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true); |
2959 | m_freem(m); |
2960 | error = EHOSTUNREACH; |
2961 | goto out; |
2962 | } |
2963 | necp_mark_packet_from_socket(packet: m, inp, policy_id, route_rule_id, skip_policy_id, pass_flags); |
2964 | |
2965 | if (net_qos_policy_restricted != 0) { |
2966 | necp_socket_update_qos_marking(inp, route: inp->inp_route.ro_rt, route_rule_id); |
2967 | } |
2968 | } |
2969 | #endif /* NECP */ |
2970 | |
2971 | #if IPSEC |
2972 | if (inp->inp_sp != NULL) { |
2973 | ipsec_setsocket(m, so); |
2974 | } |
2975 | #endif /*IPSEC*/ |
2976 | |
2977 | /* |
2978 | * The socket is kept locked while sending out packets in ip_output, even if packet chaining is not active. |
2979 | */ |
2980 | lost = 0; |
2981 | |
2982 | /* |
2983 | * Embed the flow hash in pkt hdr and mark the packet as |
2984 | * capable of flow controlling |
2985 | */ |
2986 | m->m_pkthdr.pkt_flowsrc = FLOWSRC_INPCB; |
2987 | m->m_pkthdr.pkt_flowid = inp->inp_flowhash; |
2988 | m->m_pkthdr.pkt_flags |= (PKTF_FLOW_ID | PKTF_FLOW_LOCALSRC | PKTF_FLOW_ADV); |
2989 | m->m_pkthdr.pkt_proto = IPPROTO_TCP; |
2990 | m->m_pkthdr.tx_tcp_pid = so->last_pid; |
2991 | if (so->so_flags & SOF_DELEGATED) { |
2992 | m->m_pkthdr.tx_tcp_e_pid = so->e_pid; |
2993 | } else { |
2994 | m->m_pkthdr.tx_tcp_e_pid = 0; |
2995 | } |
2996 | |
2997 | m->m_nextpkt = NULL; |
2998 | |
2999 | if (inp->inp_last_outifp != NULL && |
3000 | !(inp->inp_last_outifp->if_flags & IFF_LOOPBACK)) { |
3001 | /* Hint to prioritize this packet if |
3002 | * 1. if the packet has no data |
3003 | * 2. the interface supports transmit-start model and did |
3004 | * not disable ACK prioritization. |
3005 | * 3. Only ACK flag is set. |
3006 | * 4. there is no outstanding data on this connection. |
3007 | */ |
3008 | if (len == 0 && (inp->inp_last_outifp->if_eflags & (IFEF_TXSTART | IFEF_NOACKPRI)) == IFEF_TXSTART) { |
3009 | if (th->th_flags == TH_ACK && |
3010 | tp->snd_una == tp->snd_max && |
3011 | tp->t_timer[TCPT_REXMT] == 0) { |
3012 | svc_flags |= PKT_SCF_TCP_ACK; |
3013 | } |
3014 | if (th->th_flags & TH_SYN) { |
3015 | svc_flags |= PKT_SCF_TCP_SYN; |
3016 | } |
3017 | } |
3018 | set_packet_service_class(m, so, sotc, svc_flags); |
3019 | } else { |
3020 | /* |
3021 | * Optimization for loopback just set the mbuf |
3022 | * service class |
3023 | */ |
3024 | (void) m_set_service_class(m, so_tc2msc(sotc)); |
3025 | } |
3026 | |
3027 | if ((th->th_flags & TH_SYN) && tp->t_syn_sent < UINT8_MAX) { |
3028 | tp->t_syn_sent++; |
3029 | } |
3030 | if ((th->th_flags & TH_FIN) && tp->t_fin_sent < UINT8_MAX) { |
3031 | tp->t_fin_sent++; |
3032 | } |
3033 | if ((th->th_flags & TH_RST) && tp->t_rst_sent < UINT8_MAX) { |
3034 | tp->t_rst_sent++; |
3035 | } |
3036 | TCP_LOG_TH_FLAGS(isipv6 ? (void *)ip6 : (void *)ip, th, tp, true, |
3037 | inp->inp_last_outifp != NULL ? inp->inp_last_outifp : |
3038 | inp->inp_boundifp); |
3039 | |
3040 | tp->t_pktlist_sentlen += len; |
3041 | tp->t_lastchain++; |
3042 | |
3043 | if (isipv6) { |
3044 | DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp, |
3045 | struct ip6 *, ip6, struct tcpcb *, tp, struct tcphdr *, |
3046 | th); |
3047 | } else { |
3048 | DTRACE_TCP5(send, struct mbuf *, m, struct inpcb *, inp, |
3049 | struct ip *, ip, struct tcpcb *, tp, struct tcphdr *, th); |
3050 | } |
3051 | |
3052 | if (tp->t_pktlist_head != NULL) { |
3053 | tp->t_pktlist_tail->m_nextpkt = m; |
3054 | tp->t_pktlist_tail = m; |
3055 | } else { |
3056 | packchain_newlist++; |
3057 | tp->t_pktlist_head = tp->t_pktlist_tail = m; |
3058 | } |
3059 | |
3060 | if (sendalot == 0 || (tp->t_state != TCPS_ESTABLISHED) || |
3061 | (tp->t_flags & TF_ACKNOW) || |
3062 | (tp->t_flagsext & TF_FORCE) || |
3063 | tp->t_lastchain >= tcp_packet_chaining) { |
3064 | error = 0; |
3065 | while (inp->inp_sndinprog_cnt == 0 && |
3066 | tp->t_pktlist_head != NULL) { |
3067 | packetlist = tp->t_pktlist_head; |
3068 | packchain_listadd = tp->t_lastchain; |
3069 | packchain_sent++; |
3070 | lost = tp->t_pktlist_sentlen; |
3071 | TCP_PKTLIST_CLEAR(tp); |
3072 | |
3073 | error = tcp_ip_output(so, tp, packetlist, |
3074 | packchain_listadd, tp_inp_options, |
3075 | (so_options & SO_DONTROUTE), |
3076 | (sack_rxmit || (sack_bytes_rxmt != 0)), isipv6); |
3077 | if (error) { |
3078 | /* |
3079 | * Take into account the rest of unsent |
3080 | * packets in the packet list for this tcp |
3081 | * into "lost", since we're about to free |
3082 | * the whole list below. |
3083 | */ |
3084 | lost += tp->t_pktlist_sentlen; |
3085 | break; |
3086 | } else { |
3087 | lost = 0; |
3088 | } |
3089 | } |
3090 | /* tcp was closed while we were in ip; resume close */ |
3091 | if (inp->inp_sndinprog_cnt == 0 && |
3092 | (tp->t_flags & TF_CLOSING)) { |
3093 | tp->t_flags &= ~TF_CLOSING; |
3094 | (void) tcp_close(tp); |
3095 | return 0; |
3096 | } |
3097 | } else { |
3098 | error = 0; |
3099 | packchain_looped++; |
3100 | tcpstat.tcps_sndtotal++; |
3101 | |
3102 | goto again; |
3103 | } |
3104 | if (error) { |
3105 | /* |
3106 | * Assume that the packets were lost, so back out the |
3107 | * sequence number advance, if any. Note that the "lost" |
3108 | * variable represents the amount of user data sent during |
3109 | * the recent call to ip_output_list() plus the amount of |
3110 | * user data in the packet list for this tcp at the moment. |
3111 | */ |
3112 | if (!(tp->t_flagsext & TF_FORCE) |
3113 | || tp->t_timer[TCPT_PERSIST] == 0) { |
3114 | /* |
3115 | * No need to check for TH_FIN here because |
3116 | * the TF_SENTFIN flag handles that case. |
3117 | */ |
3118 | if ((flags & TH_SYN) == 0) { |
3119 | if (sack_rxmit) { |
3120 | if (SEQ_GT((p->rxmit - lost), |
3121 | tp->snd_una)) { |
3122 | p->rxmit -= lost; |
3123 | |
3124 | if (SEQ_LT(p->rxmit, p->start)) { |
3125 | p->rxmit = p->start; |
3126 | } |
3127 | } else { |
3128 | lost = p->rxmit - tp->snd_una; |
3129 | p->rxmit = tp->snd_una; |
3130 | |
3131 | if (SEQ_LT(p->rxmit, p->start)) { |
3132 | p->rxmit = p->start; |
3133 | } |
3134 | } |
3135 | tp->sackhint.sack_bytes_rexmit -= lost; |
3136 | if (tp->sackhint.sack_bytes_rexmit < 0) { |
3137 | tp->sackhint.sack_bytes_rexmit = 0; |
3138 | } |
3139 | } else { |
3140 | if (SEQ_GT((tp->snd_nxt - lost), |
3141 | tp->snd_una)) { |
3142 | tp->snd_nxt -= lost; |
3143 | } else { |
3144 | tp->snd_nxt = tp->snd_una; |
3145 | } |
3146 | } |
3147 | } |
3148 | } |
3149 | out: |
3150 | if (tp->t_pktlist_head != NULL) { |
3151 | m_freem_list(tp->t_pktlist_head); |
3152 | } |
3153 | TCP_PKTLIST_CLEAR(tp); |
3154 | |
3155 | if (error == ENOBUFS) { |
3156 | /* |
3157 | * Set retransmit timer if not currently set |
3158 | * when we failed to send a segment that can be |
3159 | * retransmitted (i.e. not pure ack or rst) |
3160 | */ |
3161 | if (tp->t_timer[TCPT_REXMT] == 0 && |
3162 | tp->t_timer[TCPT_PERSIST] == 0 && |
3163 | (len != 0 || (flags & (TH_SYN | TH_FIN)) != 0 || |
3164 | so->so_snd.sb_cc > 0)) { |
3165 | tp->t_timer[TCPT_REXMT] = |
3166 | OFFSET_FROM_START(tp, tp->t_rxtcur); |
3167 | } |
3168 | tp->snd_cwnd = tp->t_maxseg; |
3169 | tp->t_bytes_acked = 0; |
3170 | tcp_check_timer_state(tp); |
3171 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0); |
3172 | |
3173 | TCP_LOG_OUTPUT(tp, "error ENOBUFS silently handled" ); |
3174 | |
3175 | tcp_ccdbg_trace(tp, NULL, event: TCP_CC_OUTPUT_ERROR); |
3176 | return 0; |
3177 | } |
3178 | if (error == EMSGSIZE) { |
3179 | /* |
3180 | * ip_output() will have already fixed the route |
3181 | * for us. tcp_mtudisc() will, as its last action, |
3182 | * initiate retransmission, so it is important to |
3183 | * not do so here. |
3184 | * |
3185 | * If TSO was active we either got an interface |
3186 | * without TSO capabilits or TSO was turned off. |
3187 | * Disable it for this connection as too and |
3188 | * immediatly retry with MSS sized segments generated |
3189 | * by this function. |
3190 | */ |
3191 | if (tso) { |
3192 | tp->t_flags &= ~TF_TSO; |
3193 | } |
3194 | |
3195 | tcp_mtudisc(inp, 0); |
3196 | tcp_check_timer_state(tp); |
3197 | |
3198 | TCP_LOG_OUTPUT(tp, "error EMSGSIZE silently handled" ); |
3199 | |
3200 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0); |
3201 | return 0; |
3202 | } |
3203 | /* |
3204 | * Unless this is due to interface restriction policy, |
3205 | * treat EHOSTUNREACH/ENETDOWN/EADDRNOTAVAIL as a soft error. |
3206 | */ |
3207 | if ((error == EHOSTUNREACH || error == ENETDOWN || error == EADDRNOTAVAIL) && |
3208 | TCPS_HAVERCVDSYN(tp->t_state) && |
3209 | !inp_restricted_send(inp, inp->inp_last_outifp)) { |
3210 | tp->t_softerror = error; |
3211 | TCP_LOG_OUTPUT(tp, "soft error %d silently handled" , error); |
3212 | error = 0; |
3213 | } else { |
3214 | TCP_LOG_OUTPUT(tp, "error %d" , error); |
3215 | } |
3216 | tcp_check_timer_state(tp); |
3217 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0); |
3218 | return error; |
3219 | } |
3220 | |
3221 | tcpstat.tcps_sndtotal++; |
3222 | |
3223 | KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_END, 0, 0, 0, 0, 0); |
3224 | if (sendalot) { |
3225 | goto again; |
3226 | } |
3227 | |
3228 | tcp_check_timer_state(tp); |
3229 | |
3230 | return 0; |
3231 | } |
3232 | |
3233 | static int |
3234 | tcp_ip_output(struct socket *so, struct tcpcb *tp, struct mbuf *pkt, |
3235 | int cnt, struct mbuf *opt, int flags, int sack_in_progress, boolean_t isipv6) |
3236 | { |
3237 | int error = 0; |
3238 | boolean_t chain; |
3239 | boolean_t unlocked = FALSE; |
3240 | boolean_t ifdenied = FALSE; |
3241 | struct inpcb *inp = tp->t_inpcb; |
3242 | struct ifnet *outif = NULL; |
3243 | bool check_qos_marking_again = (so->so_flags1 & SOF1_QOSMARKING_POLICY_OVERRIDE) ? FALSE : TRUE; |
3244 | |
3245 | union { |
3246 | struct route _ro; |
3247 | struct route_in6 _ro6; |
3248 | } route_u_ = {}; |
3249 | #define ro route_u_._ro |
3250 | #define ro6 route_u_._ro6 |
3251 | |
3252 | union { |
3253 | struct ip_out_args _ipoa; |
3254 | struct ip6_out_args _ip6oa; |
3255 | } out_args_u_ = {}; |
3256 | #define ipoa out_args_u_._ipoa |
3257 | #define ip6oa out_args_u_._ip6oa |
3258 | |
3259 | if (isipv6) { |
3260 | ip6oa.ip6oa_boundif = IFSCOPE_NONE; |
3261 | ip6oa.ip6oa_flags = IP6OAF_SELECT_SRCIF | IP6OAF_BOUND_SRCADDR; |
3262 | ip6oa.ip6oa_sotc = SO_TC_UNSPEC; |
3263 | ip6oa.ip6oa_netsvctype = _NET_SERVICE_TYPE_UNSPEC; |
3264 | } else { |
3265 | ipoa.ipoa_boundif = IFSCOPE_NONE; |
3266 | ipoa.ipoa_flags = IPOAF_SELECT_SRCIF | IPOAF_BOUND_SRCADDR; |
3267 | ipoa.ipoa_sotc = SO_TC_UNSPEC; |
3268 | ipoa.ipoa_netsvctype = _NET_SERVICE_TYPE_UNSPEC; |
3269 | } |
3270 | |
3271 | struct flowadv *adv = |
3272 | (isipv6 ? &ip6oa.ip6oa_flowadv : &ipoa.ipoa_flowadv); |
3273 | |
3274 | /* If socket was bound to an ifindex, tell ip_output about it */ |
3275 | if (inp->inp_flags & INP_BOUND_IF) { |
3276 | if (isipv6) { |
3277 | ip6oa.ip6oa_boundif = inp->inp_boundifp->if_index; |
3278 | ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF; |
3279 | } else { |
3280 | ipoa.ipoa_boundif = inp->inp_boundifp->if_index; |
3281 | ipoa.ipoa_flags |= IPOAF_BOUND_IF; |
3282 | } |
3283 | } else if (!in6_embedded_scope && isipv6 && (IN6_IS_SCOPE_EMBED(&inp->in6p_faddr))) { |
3284 | ip6oa.ip6oa_boundif = inp->inp_fifscope; |
3285 | ip6oa.ip6oa_flags |= IP6OAF_BOUND_IF; |
3286 | } |
3287 | |
3288 | if (INP_NO_CELLULAR(inp)) { |
3289 | if (isipv6) { |
3290 | ip6oa.ip6oa_flags |= IP6OAF_NO_CELLULAR; |
3291 | } else { |
3292 | ipoa.ipoa_flags |= IPOAF_NO_CELLULAR; |
3293 | } |
3294 | } |
3295 | if (INP_NO_EXPENSIVE(inp)) { |
3296 | if (isipv6) { |
3297 | ip6oa.ip6oa_flags |= IP6OAF_NO_EXPENSIVE; |
3298 | } else { |
3299 | ipoa.ipoa_flags |= IPOAF_NO_EXPENSIVE; |
3300 | } |
3301 | } |
3302 | if (INP_NO_CONSTRAINED(inp)) { |
3303 | if (isipv6) { |
3304 | ip6oa.ip6oa_flags |= IP6OAF_NO_CONSTRAINED; |
3305 | } else { |
3306 | ipoa.ipoa_flags |= IPOAF_NO_CONSTRAINED; |
3307 | } |
3308 | } |
3309 | if (INP_AWDL_UNRESTRICTED(inp)) { |
3310 | if (isipv6) { |
3311 | ip6oa.ip6oa_flags |= IP6OAF_AWDL_UNRESTRICTED; |
3312 | } else { |
3313 | ipoa.ipoa_flags |= IPOAF_AWDL_UNRESTRICTED; |
3314 | } |
3315 | } |
3316 | if (INP_INTCOPROC_ALLOWED(inp) && isipv6) { |
3317 | ip6oa.ip6oa_flags |= IP6OAF_INTCOPROC_ALLOWED; |
3318 | } |
3319 | if (INP_MANAGEMENT_ALLOWED(inp)) { |
3320 | if (isipv6) { |
3321 | ip6oa.ip6oa_flags |= IP6OAF_MANAGEMENT_ALLOWED; |
3322 | } else { |
3323 | ipoa.ipoa_flags |= IPOAF_MANAGEMENT_ALLOWED; |
3324 | } |
3325 | } |
3326 | if (isipv6) { |
3327 | ip6oa.ip6oa_sotc = so->so_traffic_class; |
3328 | ip6oa.ip6oa_netsvctype = so->so_netsvctype; |
3329 | ip6oa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount; |
3330 | } else { |
3331 | ipoa.ipoa_sotc = so->so_traffic_class; |
3332 | ipoa.ipoa_netsvctype = so->so_netsvctype; |
3333 | ipoa.qos_marking_gencount = inp->inp_policyresult.results.qos_marking_gencount; |
3334 | } |
3335 | if ((so->so_flags1 & SOF1_QOSMARKING_ALLOWED)) { |
3336 | if (isipv6) { |
3337 | ip6oa.ip6oa_flags |= IP6OAF_QOSMARKING_ALLOWED; |
3338 | } else { |
3339 | ipoa.ipoa_flags |= IPOAF_QOSMARKING_ALLOWED; |
3340 | } |
3341 | } |
3342 | if (check_qos_marking_again) { |
3343 | if (isipv6) { |
3344 | ip6oa.ip6oa_flags |= IP6OAF_REDO_QOSMARKING_POLICY; |
3345 | } else { |
3346 | ipoa.ipoa_flags |= IPOAF_REDO_QOSMARKING_POLICY; |
3347 | } |
3348 | } |
3349 | if (isipv6) { |
3350 | flags |= IPV6_OUTARGS; |
3351 | } else { |
3352 | flags |= IP_OUTARGS; |
3353 | } |
3354 | |
3355 | /* Copy the cached route and take an extra reference */ |
3356 | if (isipv6) { |
3357 | in6p_route_copyout(inp, &ro6); |
3358 | } else { |
3359 | inp_route_copyout(inp, &ro); |
3360 | } |
3361 | #if (DEBUG || DEVELOPMENT) |
3362 | if ((so->so_flags & SOF_MARK_WAKE_PKT) && pkt != NULL) { |
3363 | so->so_flags &= ~SOF_MARK_WAKE_PKT; |
3364 | pkt->m_pkthdr.pkt_flags |= PKTF_WAKE_PKT; |
3365 | } |
3366 | #endif /* (DEBUG || DEVELOPMENT) */ |
3367 | |
3368 | /* |
3369 | * Make sure ACK/DELACK conditions are cleared before |
3370 | * we unlock the socket. |
3371 | */ |
3372 | tp->last_ack_sent = tp->rcv_nxt; |
3373 | tp->t_flags &= ~(TF_ACKNOW | TF_DELACK); |
3374 | tp->t_timer[TCPT_DELACK] = 0; |
3375 | tp->t_unacksegs = 0; |
3376 | tp->t_unacksegs_ce = 0; |
3377 | |
3378 | /* Increment the count of outstanding send operations */ |
3379 | inp->inp_sndinprog_cnt++; |
3380 | |
3381 | /* |
3382 | * If allowed, unlock TCP socket while in IP |
3383 | * but only if the connection is established and |
3384 | * in a normal mode where reentrancy on the tcpcb won't be |
3385 | * an issue: |
3386 | * - there is no SACK episode |
3387 | * - we're not in Fast Recovery mode |
3388 | * - if we're not sending from an upcall. |
3389 | */ |
3390 | if (tcp_output_unlocked && !so->so_upcallusecount && |
3391 | (tp->t_state == TCPS_ESTABLISHED) && (sack_in_progress == 0) && |
3392 | !IN_FASTRECOVERY(tp) && !(so->so_flags & SOF_MP_SUBFLOW)) { |
3393 | unlocked = TRUE; |
3394 | socket_unlock(so, refcount: 0); |
3395 | } |
3396 | |
3397 | /* |
3398 | * Don't send down a chain of packets when: |
3399 | * - TCP chaining is disabled |
3400 | * - there is an IPsec rule set |
3401 | * - there is a non default rule set for the firewall |
3402 | */ |
3403 | |
3404 | chain = tcp_packet_chaining > 1 |
3405 | #if IPSEC |
3406 | && ipsec_bypass |
3407 | #endif |
3408 | ; // I'm important, not extraneous |
3409 | |
3410 | while (pkt != NULL) { |
3411 | struct mbuf *npkt = pkt->m_nextpkt; |
3412 | |
3413 | if (!chain) { |
3414 | pkt->m_nextpkt = NULL; |
3415 | /* |
3416 | * If we are not chaining, make sure to set the packet |
3417 | * list count to 0 so that IP takes the right path; |
3418 | * this is important for cases such as IPsec where a |
3419 | * single mbuf might result in multiple mbufs as part |
3420 | * of the encapsulation. If a non-zero count is passed |
3421 | * down to IP, the head of the chain might change and |
3422 | * we could end up skipping it (thus generating bogus |
3423 | * packets). Fixing it in IP would be desirable, but |
3424 | * for now this would do it. |
3425 | */ |
3426 | cnt = 0; |
3427 | } |
3428 | if (isipv6) { |
3429 | error = ip6_output_list(pkt, cnt, |
3430 | inp->in6p_outputopts, &ro6, flags, NULL, NULL, |
3431 | &ip6oa); |
3432 | ifdenied = (ip6oa.ip6oa_flags & IP6OAF_R_IFDENIED); |
3433 | } else { |
3434 | error = ip_output_list(pkt, cnt, opt, &ro, flags, NULL, |
3435 | &ipoa); |
3436 | ifdenied = (ipoa.ipoa_flags & IPOAF_R_IFDENIED); |
3437 | } |
3438 | |
3439 | if (chain || error) { |
3440 | /* |
3441 | * If we sent down a chain then we are done since |
3442 | * the callee had taken care of everything; else |
3443 | * we need to free the rest of the chain ourselves. |
3444 | */ |
3445 | if (!chain) { |
3446 | m_freem_list(npkt); |
3447 | } |
3448 | break; |
3449 | } |
3450 | pkt = npkt; |
3451 | } |
3452 | |
3453 | if (unlocked) { |
3454 | socket_lock(so, refcount: 0); |
3455 | } |
3456 | |
3457 | /* |
3458 | * Enter flow controlled state if the connection is established |
3459 | * and is not in recovery. Flow control is allowed only if there |
3460 | * is outstanding data. |
3461 | * |
3462 | * A connection will enter suspended state even if it is in |
3463 | * recovery. |
3464 | */ |
3465 | if (((adv->code == FADV_FLOW_CONTROLLED && !IN_FASTRECOVERY(tp)) || |
3466 | adv->code == FADV_SUSPENDED) && |
3467 | !(tp->t_flags & TF_CLOSING) && |
3468 | tp->t_state == TCPS_ESTABLISHED && |
3469 | SEQ_GT(tp->snd_max, tp->snd_una)) { |
3470 | int rc; |
3471 | rc = inp_set_fc_state(inp, advcode: adv->code); |
3472 | |
3473 | if (rc == 1) { |
3474 | tcp_ccdbg_trace(tp, NULL, |
3475 | event: ((adv->code == FADV_FLOW_CONTROLLED) ? |
3476 | TCP_CC_FLOW_CONTROL : TCP_CC_SUSPEND)); |
3477 | if (adv->code == FADV_FLOW_CONTROLLED) { |
3478 | TCP_LOG_OUTPUT(tp, "flow controlled" ); |
3479 | } else { |
3480 | TCP_LOG_OUTPUT(tp, "flow suspended" ); |
3481 | } |
3482 | } |
3483 | } |
3484 | |
3485 | /* |
3486 | * When an interface queue gets suspended, some of the |
3487 | * packets are dropped. Return ENOBUFS, to update the |
3488 | * pcb state. |
3489 | */ |
3490 | if (adv->code == FADV_SUSPENDED) { |
3491 | error = ENOBUFS; |
3492 | } |
3493 | |
3494 | VERIFY(inp->inp_sndinprog_cnt > 0); |
3495 | if (--inp->inp_sndinprog_cnt == 0) { |
3496 | inp->inp_flags &= ~(INP_FC_FEEDBACK); |
3497 | if (inp->inp_sndingprog_waiters > 0) { |
3498 | wakeup(chan: &inp->inp_sndinprog_cnt); |
3499 | } |
3500 | } |
3501 | |
3502 | if (isipv6) { |
3503 | /* |
3504 | * When an NECP IP tunnel policy forces the outbound interface, |
3505 | * ip6_output_list() informs the transport layer what is the actual |
3506 | * outgoing interface |
3507 | */ |
3508 | if (ip6oa.ip6oa_flags & IP6OAF_BOUND_IF) { |
3509 | outif = ifindex2ifnet[ip6oa.ip6oa_boundif]; |
3510 | } else if (ro6.ro_rt != NULL) { |
3511 | outif = ro6.ro_rt->rt_ifp; |
3512 | } |
3513 | } else { |
3514 | if (ro.ro_rt != NULL) { |
3515 | outif = ro.ro_rt->rt_ifp; |
3516 | } |
3517 | } |
3518 | if (check_qos_marking_again) { |
3519 | uint32_t qos_marking_gencount; |
3520 | bool allow_qos_marking; |
3521 | if (isipv6) { |
3522 | qos_marking_gencount = ip6oa.qos_marking_gencount; |
3523 | allow_qos_marking = ip6oa.ip6oa_flags & IP6OAF_QOSMARKING_ALLOWED ? TRUE : FALSE; |
3524 | } else { |
3525 | qos_marking_gencount = ipoa.qos_marking_gencount; |
3526 | allow_qos_marking = ipoa.ipoa_flags & IPOAF_QOSMARKING_ALLOWED ? TRUE : FALSE; |
3527 | } |
3528 | inp->inp_policyresult.results.qos_marking_gencount = qos_marking_gencount; |
3529 | if (allow_qos_marking == TRUE) { |
3530 | inp->inp_socket->so_flags1 |= SOF1_QOSMARKING_ALLOWED; |
3531 | } else { |
3532 | inp->inp_socket->so_flags1 &= ~SOF1_QOSMARKING_ALLOWED; |
3533 | } |
3534 | } |
3535 | |
3536 | if (outif != NULL && outif != inp->inp_last_outifp) { |
3537 | /* Update the send byte count */ |
3538 | if (so->so_snd.sb_cc > 0 && so->so_snd.sb_flags & SB_SNDBYTE_CNT) { |
3539 | inp_decr_sndbytes_total(so, so->so_snd.sb_cc); |
3540 | inp_decr_sndbytes_allunsent(so, tp->snd_una); |
3541 | so->so_snd.sb_flags &= ~SB_SNDBYTE_CNT; |
3542 | } |
3543 | inp->inp_last_outifp = outif; |
3544 | #if SKYWALK |
3545 | if (NETNS_TOKEN_VALID(&inp->inp_netns_token)) { |
3546 | netns_set_ifnet(token: &inp->inp_netns_token, ifp: inp->inp_last_outifp); |
3547 | } |
3548 | #endif /* SKYWALK */ |
3549 | } |
3550 | |
3551 | if (error != 0 && ifdenied && |
3552 | (INP_NO_CELLULAR(inp) || INP_NO_EXPENSIVE(inp) || INP_NO_CONSTRAINED(inp))) { |
3553 | soevent(so, |
3554 | hint: (SO_FILT_HINT_LOCKED | SO_FILT_HINT_IFDENIED)); |
3555 | } |
3556 | |
3557 | /* Synchronize cached PCB route & options */ |
3558 | if (isipv6) { |
3559 | in6p_route_copyin(inp, &ro6); |
3560 | } else { |
3561 | inp_route_copyin(inp, &ro); |
3562 | } |
3563 | |
3564 | if (tp->t_state < TCPS_ESTABLISHED && tp->t_rxtshift == 0 && |
3565 | tp->t_inpcb->inp_route.ro_rt != NULL) { |
3566 | /* If we found the route and there is an rtt on it |
3567 | * reset the retransmit timer |
3568 | */ |
3569 | tcp_getrt_rtt(tp, rt: tp->t_inpcb->in6p_route.ro_rt); |
3570 | tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur); |
3571 | } |
3572 | return error; |
3573 | #undef ro |
3574 | #undef ro6 |
3575 | #undef ipoa |
3576 | #undef ip6oa |
3577 | } |
3578 | |
3579 | int tcptv_persmin_val = TCPTV_PERSMIN; |
3580 | |
3581 | void |
3582 | tcp_setpersist(struct tcpcb *tp) |
3583 | { |
3584 | int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1; |
3585 | |
3586 | /* If a PERSIST_TIMER option was set we will limit the |
3587 | * time the persist timer will be active for that connection |
3588 | * in order to avoid DOS by using zero window probes. |
3589 | * see rdar://5805356 |
3590 | */ |
3591 | |
3592 | if (tp->t_persist_timeout != 0 && |
3593 | tp->t_timer[TCPT_PERSIST] == 0 && |
3594 | tp->t_persist_stop == 0) { |
3595 | tp->t_persist_stop = tcp_now + tp->t_persist_timeout; |
3596 | } |
3597 | |
3598 | /* |
3599 | * Start/restart persistance timer. |
3600 | */ |
3601 | TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], |
3602 | t * tcp_backoff[tp->t_rxtshift], |
3603 | tcptv_persmin_val, TCPTV_PERSMAX, 0); |
3604 | tp->t_timer[TCPT_PERSIST] = OFFSET_FROM_START(tp, tp->t_timer[TCPT_PERSIST]); |
3605 | |
3606 | if (tp->t_rxtshift < TCP_MAXRXTSHIFT) { |
3607 | tp->t_rxtshift++; |
3608 | } |
3609 | } |
3610 | |
3611 | static int |
3612 | tcp_recv_throttle(struct tcpcb *tp) |
3613 | { |
3614 | uint32_t base_rtt, newsize; |
3615 | struct sockbuf *sbrcv = &tp->t_inpcb->inp_socket->so_rcv; |
3616 | |
3617 | if (tcp_use_rtt_recvbg == 1 && |
3618 | TSTMP_SUPPORTED(tp)) { |
3619 | /* |
3620 | * Timestamps are supported on this connection. Use |
3621 | * RTT to look for an increase in latency. |
3622 | */ |
3623 | |
3624 | /* |
3625 | * If the connection is already being throttled, leave it |
3626 | * in that state until rtt comes closer to base rtt |
3627 | */ |
3628 | if (tp->t_flagsext & TF_RECV_THROTTLE) { |
3629 | return 1; |
3630 | } |
3631 | |
3632 | base_rtt = get_base_rtt(tp); |
3633 | |
3634 | if (base_rtt != 0 && tp->t_rttcur != 0) { |
3635 | /* |
3636 | * if latency increased on a background flow, |
3637 | * return 1 to start throttling. |
3638 | */ |
3639 | if (tp->t_rttcur > (base_rtt + target_qdelay)) { |
3640 | tp->t_flagsext |= TF_RECV_THROTTLE; |
3641 | if (tp->t_recv_throttle_ts == 0) { |
3642 | tp->t_recv_throttle_ts = tcp_now; |
3643 | } |
3644 | /* |
3645 | * Reduce the recv socket buffer size to |
3646 | * minimize latecy. |
3647 | */ |
3648 | if (sbrcv->sb_idealsize > |
3649 | tcp_recv_throttle_minwin) { |
3650 | newsize = sbrcv->sb_idealsize >> 1; |
3651 | /* Set a minimum of 16 K */ |
3652 | newsize = |
3653 | max(a: newsize, |
3654 | b: tcp_recv_throttle_minwin); |
3655 | sbrcv->sb_idealsize = newsize; |
3656 | } |
3657 | return 1; |
3658 | } else { |
3659 | return 0; |
3660 | } |
3661 | } |
3662 | } |
3663 | |
3664 | /* |
3665 | * Timestamps are not supported or there is no good RTT |
3666 | * measurement. Use IPDV in this case. |
3667 | */ |
3668 | if (tp->acc_iaj > tcp_acc_iaj_react_limit) { |
3669 | return 1; |
3670 | } |
3671 | |
3672 | return 0; |
3673 | } |
3674 | |