1/*
2 * Copyright (c) 2007-2011 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/*
30 * Copyright (c) 1991-1997 Regents of the University of California.
31 * All rights reserved.
32 *
33 * Redistribution and use in source and binary forms, with or without
34 * modification, are permitted provided that the following conditions
35 * are met:
36 * 1. Redistributions of source code must retain the above copyright
37 * notice, this list of conditions and the following disclaimer.
38 * 2. Redistributions in binary form must reproduce the above copyright
39 * notice, this list of conditions and the following disclaimer in the
40 * documentation and/or other materials provided with the distribution.
41 * 3. All advertising materials mentioning features or use of this software
42 * must display the following acknowledgement:
43 * This product includes software developed by the Network Research
44 * Group at Lawrence Berkeley Laboratory.
45 * 4. Neither the name of the University nor of the Laboratory may be used
46 * to endorse or promote products derived from this software without
47 * specific prior written permission.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 */
61
62#include <sys/cdefs.h>
63#include <sys/param.h>
64#include <sys/mbuf.h>
65#include <sys/errno.h>
66#include <sys/random.h>
67#include <sys/kernel_types.h>
68#include <sys/sysctl.h>
69
70#include <net/if.h>
71#include <net/net_osdep.h>
72#include <net/classq/classq.h>
73
74#include <netinet/in.h>
75#include <netinet/in_systm.h>
76#include <netinet/ip.h>
77#if INET6
78#include <netinet/ip6.h>
79#endif
80#include <netinet/tcp.h>
81#include <netinet/udp.h>
82
83#include <libkern/libkern.h>
84
85#if PF_ECN
86/*
87 * read and write diffserv field in IPv4 or IPv6 header
88 */
89u_int8_t
90read_dsfield(struct mbuf *m, struct pf_mtag *t)
91{
92 struct mbuf *m0;
93 u_int8_t ds_field = 0;
94
95 if (t->pftag_hdr == NULL ||
96 !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
97 return ((u_int8_t)0);
98
99 /* verify that hdr is within the mbuf data */
100 for (m0 = m; m0 != NULL; m0 = m0->m_next)
101 if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
102 ((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
103 break;
104 if (m0 == NULL) {
105 /* ick, tag info is stale */
106 printf("%s: can't locate header!\n", __func__);
107 return ((u_int8_t)0);
108 }
109
110 if (t->pftag_flags & PF_TAG_HDR_INET) {
111 struct ip *ip = (struct ip *)(void *)t->pftag_hdr;
112
113 if (((uintptr_t)ip + sizeof (*ip)) >
114 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
115 return (0); /* out of bounds */
116
117 if (ip->ip_v != 4)
118 return ((u_int8_t)0); /* version mismatch! */
119 ds_field = ip->ip_tos;
120 }
121#if INET6
122 else if (t->pftag_flags & PF_TAG_HDR_INET6) {
123 struct ip6_hdr *ip6 = (struct ip6_hdr *)(void *)t->pftag_hdr;
124 u_int32_t flowlabel;
125
126 if (((uintptr_t)ip6 + sizeof (*ip6)) >
127 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
128 return (0); /* out of bounds */
129
130 flowlabel = ntohl(ip6->ip6_flow);
131 if ((flowlabel >> 28) != 6)
132 return ((u_int8_t)0); /* version mismatch! */
133 ds_field = (flowlabel >> 20) & 0xff;
134 }
135#endif
136 return (ds_field);
137}
138
139void
140write_dsfield(struct mbuf *m, struct pf_mtag *t, u_int8_t dsfield)
141{
142 struct mbuf *m0;
143
144 if (t->pftag_hdr == NULL ||
145 !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
146 return;
147
148 /* verify that hdr is within the mbuf data */
149 for (m0 = m; m0 != NULL; m0 = m0->m_next)
150 if (((caddr_t)t->pftag_hdr >= m0->m_data) &&
151 ((caddr_t)t->pftag_hdr < m0->m_data + m0->m_len))
152 break;
153 if (m0 == NULL) {
154 /* ick, tag info is stale */
155 printf("%s: can't locate header!\n", __func__);
156 return;
157 }
158
159 if (t->pftag_flags & PF_TAG_HDR_INET) {
160 struct ip *ip = (struct ip *)(void *)t->pftag_hdr;
161 u_int8_t old;
162 int32_t sum;
163
164 if (((uintptr_t)ip + sizeof (*ip)) >
165 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
166 return; /* out of bounds */
167
168 if (ip->ip_v != 4)
169 return; /* version mismatch! */
170 old = ip->ip_tos;
171 dsfield |= old & 3; /* leave CU bits */
172 if (old == dsfield)
173 return;
174 ip->ip_tos = dsfield;
175 /*
176 * update checksum (from RFC1624)
177 * HC' = ~(~HC + ~m + m')
178 */
179 sum = ~ntohs(ip->ip_sum) & 0xffff;
180 sum += 0xff00 + (~old & 0xff) + dsfield;
181 sum = (sum >> 16) + (sum & 0xffff);
182 sum += (sum >> 16); /* add carry */
183
184 ip->ip_sum = htons(~sum & 0xffff);
185 }
186#if INET6
187 else if (t->pftag_flags & PF_TAG_HDR_INET6) {
188 struct ip6_hdr *ip6 = (struct ip6_hdr *)t->pftag_hdr;
189 u_int32_t flowlabel;
190
191 if (((uintptr_t)ip6 + sizeof (*ip6)) >
192 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
193 return; /* out of bounds */
194
195 flowlabel = ntohl(ip6->ip6_flow);
196 if ((flowlabel >> 28) != 6)
197 return; /* version mismatch! */
198 flowlabel = (flowlabel & 0xf03fffff) | (dsfield << 20);
199 ip6->ip6_flow = htonl(flowlabel);
200 }
201#endif
202}
203
204/*
205 * try to mark CE bit to the packet.
206 * returns 1 if successfully marked, 0 otherwise.
207 */
208int
209mark_ecn(struct mbuf *m, struct pf_mtag *t, int flags)
210{
211 struct mbuf *m0;
212 void *hdr;
213 int af;
214
215 if ((hdr = t->pftag_hdr) == NULL ||
216 !(t->pftag_flags & (PF_TAG_HDR_INET|PF_TAG_HDR_INET6)))
217 return (0);
218
219 /* verify that hdr is within the mbuf data */
220 for (m0 = m; m0 != NULL; m0 = m0->m_next)
221 if (((caddr_t)hdr >= m0->m_data) &&
222 ((caddr_t)hdr < m0->m_data + m0->m_len))
223 break;
224 if (m0 == NULL) {
225 /* ick, tag info is stale */
226 printf("%s: can't locate header!\n", __func__);
227 return (0);
228 }
229
230 if (t->pftag_flags & PF_TAG_HDR_INET)
231 af = AF_INET;
232 else if (t->pftag_flags & PF_TAG_HDR_INET6)
233 af = AF_INET6;
234 else
235 af = AF_UNSPEC;
236
237 switch (af) {
238 case AF_INET:
239 if (flags & CLASSQF_ECN4) { /* REDF_ECN4 == BLUEF_ECN4 */
240 struct ip *ip = hdr;
241 u_int8_t otos;
242 int sum;
243
244 if (((uintptr_t)ip + sizeof (*ip)) >
245 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
246 return (0); /* out of bounds */
247
248 if (ip->ip_v != 4)
249 return (0); /* version mismatch! */
250 if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
251 return (0); /* not-ECT */
252 if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
253 return (1); /* already marked */
254
255 /*
256 * ecn-capable but not marked,
257 * mark CE and update checksum
258 */
259 otos = ip->ip_tos;
260 ip->ip_tos |= IPTOS_ECN_CE;
261 /*
262 * update checksum (from RFC1624) only if hw
263 * checksum is not supported.
264 * HC' = ~(~HC + ~m + m')
265 */
266 if (!(m->m_pkthdr.csum_flags & CSUM_DELAY_IP)) {
267 sum = ~ntohs(ip->ip_sum) & 0xffff;
268 sum += (~otos & 0xffff) + ip->ip_tos;
269 sum = (sum >> 16) + (sum & 0xffff);
270 sum += (sum >> 16); /* add carry */
271 ip->ip_sum = htons(~sum & 0xffff);
272 }
273 return (1);
274 }
275 break;
276#if INET6
277 case AF_INET6:
278 if (flags & CLASSQF_ECN6) { /* REDF_ECN6 == BLUEF_ECN6 */
279 struct ip6_hdr *ip6 = hdr;
280 u_int32_t flowlabel;
281
282 if (((uintptr_t)ip6 + sizeof (*ip6)) >
283 ((uintptr_t)mbuf_datastart(m0) + mbuf_maxlen(m0)))
284 return (0); /* out of bounds */
285
286 flowlabel = ntohl(ip6->ip6_flow);
287 if ((flowlabel >> 28) != 6)
288 return (0); /* version mismatch! */
289 if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
290 (IPTOS_ECN_NOTECT << 20))
291 return (0); /* not-ECT */
292 if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
293 (IPTOS_ECN_CE << 20))
294 return (1); /* already marked */
295 /*
296 * ecn-capable but not marked, mark CE
297 */
298 flowlabel |= (IPTOS_ECN_CE << 20);
299 ip6->ip6_flow = htonl(flowlabel);
300 return (1);
301 }
302 break;
303#endif /* INET6 */
304 }
305
306 /* not marked */
307 return (0);
308}
309#endif /* PF_ECN */
310