1 /*
2 * Copyright (c) 1992 Regents of the University of California.
3 * All rights reserved.
4 *
5 * This software was developed by the Computer Systems Engineering group
6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
7 * contributed to Berkeley.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34 /*
35 * The send and receive functions were originally implemented in udp.c and
36 * moved here. Also it is likely some more cleanup can be done, especially
37 * once we will implement the support for tcp.
38 */
39
40 #include <sys/cdefs.h>
41
42 #include <sys/param.h>
43 #include <sys/socket.h>
44 #include <sys/queue.h>
45
46 #include <string.h>
47
48 #include <net/if.h>
49 #include <netinet/in.h>
50 #include <netinet/if_ether.h>
51 #include <netinet/in_systm.h>
52
53 #include <netinet/ip.h>
54 #include <netinet/ip_var.h>
55 #include <netinet/udp.h>
56 #include <netinet/udp_var.h>
57
58 #include "stand.h"
59 #include "net.h"
60
61 typedef STAILQ_HEAD(ipqueue, ip_queue) ip_queue_t;
62 struct ip_queue {
63 void *ipq_pkt;
64 struct ip *ipq_hdr;
65 STAILQ_ENTRY(ip_queue) ipq_next;
66 };
67
68 /*
69 * Fragment re-assembly queue.
70 */
71 struct ip_reasm {
72 struct in_addr ip_src;
73 struct in_addr ip_dst;
74 uint16_t ip_id;
75 uint8_t ip_proto;
76 uint8_t ip_ttl;
77 size_t ip_total_size;
78 ip_queue_t ip_queue;
79 void *ip_pkt;
80 struct ip *ip_hdr;
81 STAILQ_ENTRY(ip_reasm) ip_next;
82 };
83
84 STAILQ_HEAD(ire_list, ip_reasm) ire_list = STAILQ_HEAD_INITIALIZER(ire_list);
85
86 /* Caller must leave room for ethernet and ip headers in front!! */
87 ssize_t
sendip(struct iodesc * d,void * pkt,size_t len,uint8_t proto)88 sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto)
89 {
90 ssize_t cc;
91 struct ip *ip;
92 u_char *ea;
93
94 #ifdef NET_DEBUG
95 if (debug) {
96 printf("sendip: proto: %x d=%p called.\n", proto, (void *)d);
97 if (d) {
98 printf("saddr: %s:%d",
99 inet_ntoa(d->myip), ntohs(d->myport));
100 printf(" daddr: %s:%d\n",
101 inet_ntoa(d->destip), ntohs(d->destport));
102 }
103 }
104 #endif
105
106 ip = (struct ip *)pkt - 1;
107 len += sizeof(*ip);
108
109 bzero(ip, sizeof(*ip));
110
111 ip->ip_v = IPVERSION; /* half-char */
112 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
113 ip->ip_len = htons(len);
114 ip->ip_p = proto; /* char */
115 ip->ip_ttl = IPDEFTTL; /* char */
116 ip->ip_src = d->myip;
117 ip->ip_dst = d->destip;
118 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
119
120 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
121 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
122 ea = arpwhohas(d, ip->ip_dst);
123 else
124 ea = arpwhohas(d, gateip);
125
126 cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
127 if (cc == -1)
128 return (-1);
129 if (cc != len)
130 panic("sendip: bad write (%zd != %zd)", cc, len);
131 return (cc - sizeof(*ip));
132 }
133
134 static void
ip_reasm_free(struct ip_reasm * ipr)135 ip_reasm_free(struct ip_reasm *ipr)
136 {
137 struct ip_queue *ipq;
138
139 while ((ipq = STAILQ_FIRST(&ipr->ip_queue)) != NULL) {
140 STAILQ_REMOVE_HEAD(&ipr->ip_queue, ipq_next);
141 free(ipq->ipq_pkt);
142 free(ipq);
143 }
144 free(ipr->ip_pkt);
145 free(ipr);
146 }
147
148 static int
ip_reasm_add(struct ip_reasm * ipr,void * pkt,struct ip * ip)149 ip_reasm_add(struct ip_reasm *ipr, void *pkt, struct ip *ip)
150 {
151 struct ip_queue *ipq, *prev, *p;
152
153 if ((ipq = calloc(1, sizeof (*ipq))) == NULL)
154 return (1);
155
156 ipq->ipq_pkt = pkt;
157 ipq->ipq_hdr = ip;
158
159 prev = NULL;
160 STAILQ_FOREACH(p, &ipr->ip_queue, ipq_next) {
161 if ((ntohs(p->ipq_hdr->ip_off) & IP_OFFMASK) <
162 (ntohs(ip->ip_off) & IP_OFFMASK)) {
163 prev = p;
164 continue;
165 }
166 if (prev == NULL)
167 break;
168
169 STAILQ_INSERT_AFTER(&ipr->ip_queue, prev, ipq, ipq_next);
170 return (0);
171 }
172 STAILQ_INSERT_HEAD(&ipr->ip_queue, ipq, ipq_next);
173 return (0);
174 }
175
176 /*
177 * Receive a IP packet and validate it is for us.
178 */
179 static ssize_t
readipv4(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)180 readipv4(struct iodesc *d, void **pkt, void **payload, time_t tleft,
181 uint8_t proto)
182 {
183 ssize_t n;
184 size_t hlen;
185 struct ether_header *eh;
186 struct ip *ip;
187 struct udphdr *uh;
188 uint16_t etype; /* host order */
189 char *ptr;
190 struct ip_reasm *ipr;
191 struct ip_queue *ipq, *last;
192
193 #ifdef NET_DEBUG
194 if (debug)
195 printf("readip: called\n");
196 #endif
197
198 ip = NULL;
199 ptr = NULL;
200 n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype);
201 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) {
202 free(ptr);
203 return (-1);
204 }
205
206 /* Ethernet address checks now in readether() */
207
208 /* Need to respond to ARP requests. */
209 if (etype == ETHERTYPE_ARP) {
210 struct arphdr *ah = (void *)ip;
211 if (ah->ar_op == htons(ARPOP_REQUEST)) {
212 /* Send ARP reply */
213 arp_reply(d, ah);
214 }
215 free(ptr);
216 errno = EAGAIN; /* Call me again. */
217 return (-1);
218 }
219
220 if (etype != ETHERTYPE_IP) {
221 #ifdef NET_DEBUG
222 if (debug)
223 printf("readip: not IP. ether_type=%x\n", etype);
224 #endif
225 free(ptr);
226 return (-1);
227 }
228
229 /* Check ip header */
230 if (ip->ip_v != IPVERSION || /* half char */
231 ip->ip_p != proto) {
232 #ifdef NET_DEBUG
233 if (debug) {
234 printf("readip: IP version or proto. ip_v=%d ip_p=%d\n",
235 ip->ip_v, ip->ip_p);
236 }
237 #endif
238 free(ptr);
239 return (-1);
240 }
241
242 hlen = ip->ip_hl << 2;
243 if (hlen < sizeof(*ip) ||
244 in_cksum(ip, hlen) != 0) {
245 #ifdef NET_DEBUG
246 if (debug)
247 printf("readip: short hdr or bad cksum.\n");
248 #endif
249 free(ptr);
250 return (-1);
251 }
252 if (n < ntohs(ip->ip_len)) {
253 #ifdef NET_DEBUG
254 if (debug)
255 printf("readip: bad length %d < %d.\n",
256 (int)n, ntohs(ip->ip_len));
257 #endif
258 free(ptr);
259 return (-1);
260 }
261 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
262 #ifdef NET_DEBUG
263 if (debug) {
264 printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
265 printf("%s\n", inet_ntoa(ip->ip_dst));
266 }
267 #endif
268 free(ptr);
269 return (-1);
270 }
271
272 /* Unfragmented packet. */
273 if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
274 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
275 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
276 /* If there were ip options, make them go away */
277 if (hlen != sizeof(*ip)) {
278 bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen);
279 ip->ip_len = htons(sizeof(*ip));
280 n -= hlen - sizeof(*ip);
281 }
282
283 n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ?
284 ntohs(ip->ip_len) - sizeof(*ip) : n;
285 *pkt = ptr;
286 *payload = (void *)((uintptr_t)ip + sizeof(*ip));
287 return (n);
288 }
289
290 STAILQ_FOREACH(ipr, &ire_list, ip_next) {
291 if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
292 ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
293 ipr->ip_id == ip->ip_id &&
294 ipr->ip_proto == ip->ip_p)
295 break;
296 }
297
298 /* Allocate new reassembly entry */
299 if (ipr == NULL) {
300 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
301 free(ptr);
302 return (-1);
303 }
304
305 ipr->ip_src = ip->ip_src;
306 ipr->ip_dst = ip->ip_dst;
307 ipr->ip_id = ip->ip_id;
308 ipr->ip_proto = ip->ip_p;
309 ipr->ip_ttl = MAXTTL;
310 STAILQ_INIT(&ipr->ip_queue);
311 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
312 }
313
314 if (ip_reasm_add(ipr, ptr, ip) != 0) {
315 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
316 free(ipr);
317 free(ptr);
318 return (-1);
319 }
320
321 if ((ntohs(ip->ip_off) & IP_MF) == 0) {
322 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
323 ipr->ip_total_size += n + sizeof (*ip);
324 ipr->ip_total_size += sizeof (struct ether_header);
325
326 ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
327 if (ipr->ip_pkt == NULL) {
328 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
329 ip_reasm_free(ipr);
330 return (-1);
331 }
332 }
333
334 /*
335 * If we do not have re-assembly buffer ipr->ip_pkt, we are still
336 * missing fragments, so just restart the read.
337 */
338 if (ipr->ip_pkt == NULL) {
339 errno = EAGAIN;
340 return (-1);
341 }
342
343 /*
344 * Walk the packet list in reassembly queue, if we got all the
345 * fragments, build the packet.
346 */
347 n = 0;
348 last = NULL;
349 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
350 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
351 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
352 ip_reasm_free(ipr);
353 return (-1);
354 }
355
356 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
357 last = ipq;
358 }
359 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
360 errno = EAGAIN;
361 return (-1);
362 }
363
364 ipq = STAILQ_FIRST(&ipr->ip_queue);
365 /* Fabricate ethernet header */
366 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
367 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
368
369 /* Fabricate IP header */
370 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
371 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
372 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
373 ipr->ip_hdr->ip_len = htons(n);
374 ipr->ip_hdr->ip_sum = 0;
375 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
376
377 n = 0;
378 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
379 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
380 char *data;
381 size_t len;
382
383 hlen = ipq->ipq_hdr->ip_hl << 2;
384 len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
385 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
386
387 bcopy(data, ptr + n, len);
388 n += len;
389 }
390
391 *pkt = ipr->ip_pkt;
392 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
393 *payload = ptr;
394
395 /* Clean up the reassembly list */
396 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
397 STAILQ_REMOVE_HEAD(&ire_list, ip_next);
398 ip_reasm_free(ipr);
399 }
400 return (n);
401 }
402
403 /*
404 * Receive a IP packet.
405 */
406 ssize_t
readip(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)407 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
408 uint8_t proto)
409 {
410 time_t t;
411 ssize_t ret = -1;
412
413 t = getsecs();
414 while ((getsecs() - t) < tleft) {
415 errno = 0;
416 ret = readipv4(d, pkt, payload, tleft, proto);
417 if (ret >= 0)
418 return (ret);
419 /* Bubble up the error if it wasn't successful */
420 if (errno != EAGAIN)
421 return (-1);
422 }
423 /* We've exhausted tleft; timeout */
424 errno = ETIMEDOUT;
425 return (-1);
426 }
427