1/*
2 * Copyright (c) 2021 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#include "tcp_includes.h"
30
31#include <sys/domain.h>
32#include <sys/sdt.h>
33
34#define TCP_CCDBG_NOUNIT 0xffffffff
35static kern_ctl_ref tcp_ccdbg_ctlref = NULL;
36volatile uint32_t tcp_ccdbg_unit = TCP_CCDBG_NOUNIT;
37
38/* Allow only one socket to connect at any time for debugging */
39static errno_t
40tcp_ccdbg_control_connect(kern_ctl_ref kctl, struct sockaddr_ctl *sac,
41 void **uinfo)
42{
43#pragma unused(kctl)
44#pragma unused(uinfo)
45
46 UInt32 old_value = TCP_CCDBG_NOUNIT;
47 UInt32 new_value = sac->sc_unit;
48
49 if (tcp_ccdbg_unit != old_value) {
50 return EALREADY;
51 }
52
53 if (OSCompareAndSwap(old_value, new_value, &tcp_ccdbg_unit)) {
54 return 0;
55 } else {
56 return EALREADY;
57 }
58}
59
60static errno_t
61tcp_ccdbg_control_disconnect(kern_ctl_ref kctl, u_int32_t unit, void *uinfo)
62{
63#pragma unused(kctl, unit, uinfo)
64
65 if (unit == tcp_ccdbg_unit) {
66 UInt32 old_value = tcp_ccdbg_unit;
67 UInt32 new_value = TCP_CCDBG_NOUNIT;
68 if (tcp_ccdbg_unit == new_value) {
69 return 0;
70 }
71
72 if (!OSCompareAndSwap(old_value, new_value,
73 &tcp_ccdbg_unit)) {
74 log(LOG_DEBUG,
75 "failed to disconnect tcp_cc debug control");
76 }
77 }
78 return 0;
79}
80
81inline void
82tcp_ccdbg_trace(struct tcpcb *tp, struct tcphdr *th, int32_t event)
83{
84#if !CONFIG_DTRACE
85#pragma unused(th)
86#endif /* !CONFIG_DTRACE */
87 struct inpcb *inp = tp->t_inpcb;
88
89 if (tcp_cc_debug && tcp_ccdbg_unit > 0) {
90 struct tcp_cc_debug_state dbg_state;
91 struct timespec tv;
92
93 bzero(s: &dbg_state, n: sizeof(dbg_state));
94
95 nanotime(ts: &tv);
96 /* Take time in seconds */
97 dbg_state.ccd_tsns = (tv.tv_sec * 1000000000) + tv.tv_nsec;
98 inet_ntop(SOCK_DOM(inp->inp_socket),
99 ((SOCK_DOM(inp->inp_socket) == PF_INET) ?
100 (void *)&inp->inp_laddr.s_addr :
101 (void *)&inp->in6p_laddr), dbg_state.ccd_srcaddr,
102 sizeof(dbg_state.ccd_srcaddr));
103 dbg_state.ccd_srcport = ntohs(inp->inp_lport);
104 inet_ntop(SOCK_DOM(inp->inp_socket),
105 ((SOCK_DOM(inp->inp_socket) == PF_INET) ?
106 (void *)&inp->inp_faddr.s_addr :
107 (void *)&inp->in6p_faddr), dbg_state.ccd_destaddr,
108 sizeof(dbg_state.ccd_destaddr));
109 dbg_state.ccd_destport = ntohs(inp->inp_fport);
110
111 dbg_state.ccd_snd_cwnd = tp->snd_cwnd;
112 dbg_state.ccd_snd_wnd = tp->snd_wnd;
113 dbg_state.ccd_snd_ssthresh = tp->snd_ssthresh;
114 dbg_state.ccd_pipeack = tp->t_pipeack;
115 dbg_state.ccd_rttcur = tp->t_rttcur;
116 dbg_state.ccd_rxtcur = tp->t_rxtcur;
117 dbg_state.ccd_srtt = tp->t_srtt >> TCP_RTT_SHIFT;
118 dbg_state.ccd_event = event;
119 dbg_state.ccd_sndcc = inp->inp_socket->so_snd.sb_cc;
120 dbg_state.ccd_sndhiwat = inp->inp_socket->so_snd.sb_hiwat;
121 dbg_state.ccd_bytes_acked = tp->t_bytes_acked;
122 dbg_state.ccd_cc_index = tp->tcp_cc_index;
123 switch (tp->tcp_cc_index) {
124 case TCP_CC_ALGO_CUBIC_INDEX:
125 dbg_state.u.cubic_state.ccd_last_max =
126 tp->t_ccstate->cub_last_max;
127 dbg_state.u.cubic_state.ccd_tcp_win =
128 tp->t_ccstate->cub_tcp_win;
129 dbg_state.u.cubic_state.ccd_avg_lastmax =
130 tp->t_ccstate->cub_avg_lastmax;
131 dbg_state.u.cubic_state.ccd_mean_deviation =
132 tp->t_ccstate->cub_mean_dev;
133 break;
134 case TCP_CC_ALGO_BACKGROUND_INDEX:
135 dbg_state.u.ledbat_state.led_base_rtt =
136 get_base_rtt(tp);
137 break;
138 default:
139 break;
140 }
141
142 ctl_enqueuedata(kctlref: tcp_ccdbg_ctlref, unit: tcp_ccdbg_unit,
143 data: &dbg_state, len: sizeof(dbg_state), flags: 0);
144 }
145 DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
146 struct tcpcb *, tp, struct tcphdr *, th, int32_t, event);
147}
148
149void
150tcp_ccdbg_control_register(void)
151{
152 struct kern_ctl_reg ccdbg_control;
153 errno_t err;
154
155 bzero(s: &ccdbg_control, n: sizeof(ccdbg_control));
156 strlcpy(dst: ccdbg_control.ctl_name, TCP_CC_CONTROL_NAME,
157 n: sizeof(ccdbg_control.ctl_name));
158 ccdbg_control.ctl_connect = tcp_ccdbg_control_connect;
159 ccdbg_control.ctl_disconnect = tcp_ccdbg_control_disconnect;
160 ccdbg_control.ctl_flags |= CTL_FLAG_PRIVILEGED;
161 ccdbg_control.ctl_flags |= CTL_FLAG_REG_SOCK_STREAM;
162 ccdbg_control.ctl_sendsize = 32 * 1024;
163
164 err = ctl_register(userkctl: &ccdbg_control, kctlref: &tcp_ccdbg_ctlref);
165 if (err != 0) {
166 log(LOG_ERR, "failed to register tcp_cc debug control");
167 }
168}
169