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/param.h>
41 #include <sys/socket.h>
42 #include <sys/queue.h>
43
44 #include <string.h>
45
46 #include <net/if.h>
47 #include <netinet/in.h>
48 #include <netinet/if_ether.h>
49 #include <netinet/in_systm.h>
50
51 #include <netinet/ip.h>
52 #include <netinet/ip_var.h>
53 #include <netinet/udp.h>
54 #include <netinet/udp_var.h>
55
56 #include "stand.h"
57 #include "net.h"
58
59 typedef STAILQ_HEAD(ipqueue, ip_queue) ip_queue_t;
60 struct ip_queue {
61 void *ipq_pkt;
62 struct ip *ipq_hdr;
63 STAILQ_ENTRY(ip_queue) ipq_next;
64 };
65
66 /*
67 * Fragment re-assembly queue.
68 */
69 struct ip_reasm {
70 struct in_addr ip_src;
71 struct in_addr ip_dst;
72 uint16_t ip_id;
73 uint8_t ip_proto;
74 uint8_t ip_ttl;
75 size_t ip_total_size;
76 ip_queue_t ip_queue;
77 void *ip_pkt;
78 struct ip *ip_hdr;
79 STAILQ_ENTRY(ip_reasm) ip_next;
80 };
81
82 STAILQ_HEAD(ire_list, ip_reasm) ire_list = STAILQ_HEAD_INITIALIZER(ire_list);
83
84 /* Caller must leave room for ethernet and ip headers in front!! */
85 ssize_t
sendip(struct iodesc * d,void * pkt,size_t len,uint8_t proto)86 sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto)
87 {
88 ssize_t cc;
89 struct ip *ip;
90 u_char *ea;
91
92 #ifdef NET_DEBUG
93 if (debug) {
94 printf("sendip: proto: %x d=%p called.\n", proto, (void *)d);
95 if (d) {
96 printf("saddr: %s:%d",
97 inet_ntoa(d->myip), ntohs(d->myport));
98 printf(" daddr: %s:%d\n",
99 inet_ntoa(d->destip), ntohs(d->destport));
100 }
101 }
102 #endif
103
104 ip = (struct ip *)pkt - 1;
105 len += sizeof(*ip);
106
107 bzero(ip, sizeof(*ip));
108
109 ip->ip_v = IPVERSION; /* half-char */
110 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
111 ip->ip_len = htons(len);
112 ip->ip_p = proto; /* char */
113 ip->ip_ttl = IPDEFTTL; /* char */
114 ip->ip_src = d->myip;
115 ip->ip_dst = d->destip;
116 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
117
118 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
119 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
120 ea = arpwhohas(d, ip->ip_dst);
121 else
122 ea = arpwhohas(d, gateip);
123
124 cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
125 if (cc == -1)
126 return (-1);
127 if (cc != len)
128 panic("sendip: bad write (%zd != %zd)", cc, len);
129 return (cc - sizeof(*ip));
130 }
131
132 static void
ip_reasm_free(struct ip_reasm * ipr)133 ip_reasm_free(struct ip_reasm *ipr)
134 {
135 struct ip_queue *ipq;
136
137 while ((ipq = STAILQ_FIRST(&ipr->ip_queue)) != NULL) {
138 STAILQ_REMOVE_HEAD(&ipr->ip_queue, ipq_next);
139 free(ipq->ipq_pkt);
140 free(ipq);
141 }
142 free(ipr->ip_pkt);
143 free(ipr);
144 }
145
146 static int
ip_reasm_add(struct ip_reasm * ipr,void * pkt,struct ip * ip)147 ip_reasm_add(struct ip_reasm *ipr, void *pkt, struct ip *ip)
148 {
149 struct ip_queue *ipq, *prev, *p;
150
151 if ((ipq = calloc(1, sizeof (*ipq))) == NULL)
152 return (1);
153
154 ipq->ipq_pkt = pkt;
155 ipq->ipq_hdr = ip;
156
157 prev = NULL;
158 STAILQ_FOREACH(p, &ipr->ip_queue, ipq_next) {
159 if ((ntohs(p->ipq_hdr->ip_off) & IP_OFFMASK) <
160 (ntohs(ip->ip_off) & IP_OFFMASK)) {
161 prev = p;
162 continue;
163 }
164 if (prev == NULL)
165 break;
166
167 STAILQ_INSERT_AFTER(&ipr->ip_queue, prev, ipq, ipq_next);
168 return (0);
169 }
170 STAILQ_INSERT_HEAD(&ipr->ip_queue, ipq, ipq_next);
171 return (0);
172 }
173
174 /*
175 * Receive a IP packet and validate it is for us.
176 */
177 static ssize_t
readipv4(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)178 readipv4(struct iodesc *d, void **pkt, void **payload, time_t tleft,
179 uint8_t proto)
180 {
181 ssize_t n;
182 size_t hlen;
183 struct ether_header *eh;
184 struct ip *ip;
185 struct udphdr *uh;
186 uint16_t etype; /* host order */
187 char *ptr;
188 struct ip_reasm *ipr;
189 struct ip_queue *ipq, *last;
190
191 #ifdef NET_DEBUG
192 if (debug)
193 printf("readip: called\n");
194 #endif
195
196 ip = NULL;
197 ptr = NULL;
198 n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype);
199 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) {
200 free(ptr);
201 return (-1);
202 }
203
204 /* Ethernet address checks now in readether() */
205
206 /* Need to respond to ARP requests. */
207 if (etype == ETHERTYPE_ARP) {
208 struct arphdr *ah = (void *)ip;
209 if (ah->ar_op == htons(ARPOP_REQUEST)) {
210 /* Send ARP reply */
211 arp_reply(d, ah);
212 }
213 free(ptr);
214 errno = EAGAIN; /* Call me again. */
215 return (-1);
216 }
217
218 if (etype != ETHERTYPE_IP) {
219 #ifdef NET_DEBUG
220 if (debug)
221 printf("readip: not IP. ether_type=%x\n", etype);
222 #endif
223 free(ptr);
224 return (-1);
225 }
226
227 /* Check ip header */
228 if (ip->ip_v != IPVERSION || /* half char */
229 ip->ip_p != proto) {
230 #ifdef NET_DEBUG
231 if (debug) {
232 printf("readip: IP version or proto. ip_v=%d ip_p=%d\n",
233 ip->ip_v, ip->ip_p);
234 }
235 #endif
236 free(ptr);
237 return (-1);
238 }
239
240 hlen = ip->ip_hl << 2;
241 if (hlen < sizeof(*ip) ||
242 in_cksum(ip, hlen) != 0) {
243 #ifdef NET_DEBUG
244 if (debug)
245 printf("readip: short hdr or bad cksum.\n");
246 #endif
247 free(ptr);
248 return (-1);
249 }
250 if (n < ntohs(ip->ip_len)) {
251 #ifdef NET_DEBUG
252 if (debug)
253 printf("readip: bad length %d < %d.\n",
254 (int)n, ntohs(ip->ip_len));
255 #endif
256 free(ptr);
257 return (-1);
258 }
259 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
260 #ifdef NET_DEBUG
261 if (debug) {
262 printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
263 printf("%s\n", inet_ntoa(ip->ip_dst));
264 }
265 #endif
266 free(ptr);
267 return (-1);
268 }
269
270 /* Unfragmented packet. */
271 if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
272 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
273 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
274 /* If there were ip options, make them go away */
275 if (hlen != sizeof(*ip)) {
276 bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen);
277 ip->ip_len = htons(sizeof(*ip));
278 n -= hlen - sizeof(*ip);
279 }
280
281 n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ?
282 ntohs(ip->ip_len) - sizeof(*ip) : n;
283 *pkt = ptr;
284 *payload = (void *)((uintptr_t)ip + sizeof(*ip));
285 return (n);
286 }
287
288 STAILQ_FOREACH(ipr, &ire_list, ip_next) {
289 if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
290 ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
291 ipr->ip_id == ip->ip_id &&
292 ipr->ip_proto == ip->ip_p)
293 break;
294 }
295
296 /* Allocate new reassembly entry */
297 if (ipr == NULL) {
298 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
299 free(ptr);
300 return (-1);
301 }
302
303 ipr->ip_src = ip->ip_src;
304 ipr->ip_dst = ip->ip_dst;
305 ipr->ip_id = ip->ip_id;
306 ipr->ip_proto = ip->ip_p;
307 ipr->ip_ttl = MAXTTL;
308 STAILQ_INIT(&ipr->ip_queue);
309 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
310 }
311
312 if (ip_reasm_add(ipr, ptr, ip) != 0) {
313 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
314 free(ipr);
315 free(ptr);
316 return (-1);
317 }
318
319 if ((ntohs(ip->ip_off) & IP_MF) == 0) {
320 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
321 ipr->ip_total_size += n + sizeof (*ip);
322 ipr->ip_total_size += sizeof (struct ether_header);
323
324 ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
325 if (ipr->ip_pkt == NULL) {
326 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
327 ip_reasm_free(ipr);
328 return (-1);
329 }
330 }
331
332 /*
333 * If we do not have re-assembly buffer ipr->ip_pkt, we are still
334 * missing fragments, so just restart the read.
335 */
336 if (ipr->ip_pkt == NULL) {
337 errno = EAGAIN;
338 return (-1);
339 }
340
341 /*
342 * Walk the packet list in reassembly queue, if we got all the
343 * fragments, build the packet.
344 */
345 n = 0;
346 last = NULL;
347 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
348 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
349 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
350 ip_reasm_free(ipr);
351 return (-1);
352 }
353
354 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
355 last = ipq;
356 }
357 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
358 errno = EAGAIN;
359 return (-1);
360 }
361
362 ipq = STAILQ_FIRST(&ipr->ip_queue);
363 /* Fabricate ethernet header */
364 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
365 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
366
367 /* Fabricate IP header */
368 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
369 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
370 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
371 ipr->ip_hdr->ip_len = htons(n);
372 ipr->ip_hdr->ip_sum = 0;
373 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
374
375 n = 0;
376 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
377 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
378 char *data;
379 size_t len;
380
381 hlen = ipq->ipq_hdr->ip_hl << 2;
382 len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
383 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
384
385 bcopy(data, ptr + n, len);
386 n += len;
387 }
388
389 *pkt = ipr->ip_pkt;
390 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
391 *payload = ptr;
392
393 /* Clean up the reassembly list */
394 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
395 STAILQ_REMOVE_HEAD(&ire_list, ip_next);
396 ip_reasm_free(ipr);
397 }
398 return (n);
399 }
400
401 /*
402 * Receive a IP packet.
403 */
404 ssize_t
readip(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)405 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
406 uint8_t proto)
407 {
408 time_t t;
409 ssize_t ret = -1;
410
411 t = getsecs();
412 while ((getsecs() - t) < tleft) {
413 errno = 0;
414 ret = readipv4(d, pkt, payload, tleft, proto);
415 if (ret >= 0)
416 return (ret);
417 /* Bubble up the error if it wasn't successful */
418 if (errno != EAGAIN)
419 return (-1);
420 }
421 /* We've exhausted tleft; timeout */
422 errno = ETIMEDOUT;
423 return (-1);
424 }
425