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/in_pcb.h>
54 #include <netinet/ip.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/udp.h>
57 #include <netinet/udp_var.h>
58
59 #include "stand.h"
60 #include "net.h"
61
62 typedef STAILQ_HEAD(ipqueue, ip_queue) ip_queue_t;
63 struct ip_queue {
64 void *ipq_pkt;
65 struct ip *ipq_hdr;
66 STAILQ_ENTRY(ip_queue) ipq_next;
67 };
68
69 /*
70 * Fragment re-assembly queue.
71 */
72 struct ip_reasm {
73 struct in_addr ip_src;
74 struct in_addr ip_dst;
75 uint16_t ip_id;
76 uint8_t ip_proto;
77 uint8_t ip_ttl;
78 size_t ip_total_size;
79 ip_queue_t ip_queue;
80 void *ip_pkt;
81 struct ip *ip_hdr;
82 STAILQ_ENTRY(ip_reasm) ip_next;
83 };
84
85 STAILQ_HEAD(ire_list, ip_reasm) ire_list = STAILQ_HEAD_INITIALIZER(ire_list);
86
87 /* Caller must leave room for ethernet and ip headers in front!! */
88 ssize_t
sendip(struct iodesc * d,void * pkt,size_t len,uint8_t proto)89 sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto)
90 {
91 ssize_t cc;
92 struct ip *ip;
93 u_char *ea;
94
95 #ifdef NET_DEBUG
96 if (debug) {
97 printf("sendip: proto: %x d=%p called.\n", proto, (void *)d);
98 if (d) {
99 printf("saddr: %s:%d",
100 inet_ntoa(d->myip), ntohs(d->myport));
101 printf(" daddr: %s:%d\n",
102 inet_ntoa(d->destip), ntohs(d->destport));
103 }
104 }
105 #endif
106
107 ip = (struct ip *)pkt - 1;
108 len += sizeof(*ip);
109
110 bzero(ip, sizeof(*ip));
111
112 ip->ip_v = IPVERSION; /* half-char */
113 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
114 ip->ip_len = htons(len);
115 ip->ip_p = proto; /* char */
116 ip->ip_ttl = IPDEFTTL; /* char */
117 ip->ip_src = d->myip;
118 ip->ip_dst = d->destip;
119 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
120
121 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
122 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
123 ea = arpwhohas(d, ip->ip_dst);
124 else
125 ea = arpwhohas(d, gateip);
126
127 cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
128 if (cc == -1)
129 return (-1);
130 if (cc != len)
131 panic("sendip: bad write (%zd != %zd)", cc, len);
132 return (cc - sizeof(*ip));
133 }
134
135 static void
ip_reasm_free(struct ip_reasm * ipr)136 ip_reasm_free(struct ip_reasm *ipr)
137 {
138 struct ip_queue *ipq;
139
140 while ((ipq = STAILQ_FIRST(&ipr->ip_queue)) != NULL) {
141 STAILQ_REMOVE_HEAD(&ipr->ip_queue, ipq_next);
142 free(ipq->ipq_pkt);
143 free(ipq);
144 }
145 free(ipr->ip_pkt);
146 free(ipr);
147 }
148
149 static int
ip_reasm_add(struct ip_reasm * ipr,void * pkt,struct ip * ip)150 ip_reasm_add(struct ip_reasm *ipr, void *pkt, struct ip *ip)
151 {
152 struct ip_queue *ipq, *prev, *p;
153
154 if ((ipq = calloc(1, sizeof (*ipq))) == NULL)
155 return (1);
156
157 ipq->ipq_pkt = pkt;
158 ipq->ipq_hdr = ip;
159
160 prev = NULL;
161 STAILQ_FOREACH(p, &ipr->ip_queue, ipq_next) {
162 if ((ntohs(p->ipq_hdr->ip_off) & IP_OFFMASK) <
163 (ntohs(ip->ip_off) & IP_OFFMASK)) {
164 prev = p;
165 continue;
166 }
167 if (prev == NULL)
168 break;
169
170 STAILQ_INSERT_AFTER(&ipr->ip_queue, prev, ipq, ipq_next);
171 return (0);
172 }
173 STAILQ_INSERT_HEAD(&ipr->ip_queue, ipq, ipq_next);
174 return (0);
175 }
176
177 /*
178 * Receive a IP packet and validate it is for us.
179 */
180 static ssize_t
readipv4(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)181 readipv4(struct iodesc *d, void **pkt, void **payload, time_t tleft,
182 uint8_t proto)
183 {
184 ssize_t n;
185 size_t hlen;
186 struct ether_header *eh;
187 struct ip *ip;
188 struct udphdr *uh;
189 uint16_t etype; /* host order */
190 char *ptr;
191 struct ip_reasm *ipr;
192 struct ip_queue *ipq, *last;
193
194 #ifdef NET_DEBUG
195 if (debug)
196 printf("readip: called\n");
197 #endif
198
199 ip = NULL;
200 ptr = NULL;
201 n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype);
202 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) {
203 free(ptr);
204 return (-1);
205 }
206
207 /* Ethernet address checks now in readether() */
208
209 /* Need to respond to ARP requests. */
210 if (etype == ETHERTYPE_ARP) {
211 struct arphdr *ah = (void *)ip;
212 if (ah->ar_op == htons(ARPOP_REQUEST)) {
213 /* Send ARP reply */
214 arp_reply(d, ah);
215 }
216 free(ptr);
217 errno = EAGAIN; /* Call me again. */
218 return (-1);
219 }
220
221 if (etype != ETHERTYPE_IP) {
222 #ifdef NET_DEBUG
223 if (debug)
224 printf("readip: not IP. ether_type=%x\n", etype);
225 #endif
226 free(ptr);
227 return (-1);
228 }
229
230 /* Check ip header */
231 if (ip->ip_v != IPVERSION || /* half char */
232 ip->ip_p != proto) {
233 #ifdef NET_DEBUG
234 if (debug) {
235 printf("readip: IP version or proto. ip_v=%d ip_p=%d\n",
236 ip->ip_v, ip->ip_p);
237 }
238 #endif
239 free(ptr);
240 return (-1);
241 }
242
243 hlen = ip->ip_hl << 2;
244 if (hlen < sizeof(*ip) ||
245 in_cksum(ip, hlen) != 0) {
246 #ifdef NET_DEBUG
247 if (debug)
248 printf("readip: short hdr or bad cksum.\n");
249 #endif
250 free(ptr);
251 return (-1);
252 }
253 if (n < ntohs(ip->ip_len)) {
254 #ifdef NET_DEBUG
255 if (debug)
256 printf("readip: bad length %d < %d.\n",
257 (int)n, ntohs(ip->ip_len));
258 #endif
259 free(ptr);
260 return (-1);
261 }
262 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
263 #ifdef NET_DEBUG
264 if (debug) {
265 printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
266 printf("%s\n", inet_ntoa(ip->ip_dst));
267 }
268 #endif
269 free(ptr);
270 return (-1);
271 }
272
273 /* Unfragmented packet. */
274 if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
275 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
276 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
277 /* If there were ip options, make them go away */
278 if (hlen != sizeof(*ip)) {
279 bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen);
280 ip->ip_len = htons(sizeof(*ip));
281 n -= hlen - sizeof(*ip);
282 }
283
284 n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ?
285 ntohs(ip->ip_len) - sizeof(*ip) : n;
286 *pkt = ptr;
287 *payload = (void *)((uintptr_t)ip + sizeof(*ip));
288 return (n);
289 }
290
291 STAILQ_FOREACH(ipr, &ire_list, ip_next) {
292 if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
293 ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
294 ipr->ip_id == ip->ip_id &&
295 ipr->ip_proto == ip->ip_p)
296 break;
297 }
298
299 /* Allocate new reassembly entry */
300 if (ipr == NULL) {
301 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
302 free(ptr);
303 return (-1);
304 }
305
306 ipr->ip_src = ip->ip_src;
307 ipr->ip_dst = ip->ip_dst;
308 ipr->ip_id = ip->ip_id;
309 ipr->ip_proto = ip->ip_p;
310 ipr->ip_ttl = MAXTTL;
311 STAILQ_INIT(&ipr->ip_queue);
312 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
313 }
314
315 if (ip_reasm_add(ipr, ptr, ip) != 0) {
316 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
317 free(ipr);
318 free(ptr);
319 return (-1);
320 }
321
322 if ((ntohs(ip->ip_off) & IP_MF) == 0) {
323 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
324 ipr->ip_total_size += n + sizeof (*ip);
325 ipr->ip_total_size += sizeof (struct ether_header);
326
327 ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
328 if (ipr->ip_pkt == NULL) {
329 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
330 ip_reasm_free(ipr);
331 return (-1);
332 }
333 }
334
335 /*
336 * If we do not have re-assembly buffer ipr->ip_pkt, we are still
337 * missing fragments, so just restart the read.
338 */
339 if (ipr->ip_pkt == NULL) {
340 errno = EAGAIN;
341 return (-1);
342 }
343
344 /*
345 * Walk the packet list in reassembly queue, if we got all the
346 * fragments, build the packet.
347 */
348 n = 0;
349 last = NULL;
350 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
351 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
352 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
353 ip_reasm_free(ipr);
354 return (-1);
355 }
356
357 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
358 last = ipq;
359 }
360 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
361 errno = EAGAIN;
362 return (-1);
363 }
364
365 ipq = STAILQ_FIRST(&ipr->ip_queue);
366 /* Fabricate ethernet header */
367 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
368 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
369
370 /* Fabricate IP header */
371 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
372 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
373 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
374 ipr->ip_hdr->ip_len = htons(n);
375 ipr->ip_hdr->ip_sum = 0;
376 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
377
378 n = 0;
379 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
380 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
381 char *data;
382 size_t len;
383
384 hlen = ipq->ipq_hdr->ip_hl << 2;
385 len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
386 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
387
388 bcopy(data, ptr + n, len);
389 n += len;
390 }
391
392 *pkt = ipr->ip_pkt;
393 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
394 *payload = ptr;
395
396 /* Clean up the reassembly list */
397 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
398 STAILQ_REMOVE_HEAD(&ire_list, ip_next);
399 ip_reasm_free(ipr);
400 }
401 return (n);
402 }
403
404 /*
405 * Receive a IP packet.
406 */
407 ssize_t
readip(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)408 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
409 uint8_t proto)
410 {
411 time_t t;
412 ssize_t ret = -1;
413
414 t = getsecs();
415 while ((getsecs() - t) < tleft) {
416 errno = 0;
417 ret = readipv4(d, pkt, payload, tleft, proto);
418 if (ret >= 0)
419 return (ret);
420 /* Bubble up the error if it wasn't successful */
421 if (errno != EAGAIN)
422 return (-1);
423 }
424 /* We've exhausted tleft; timeout */
425 errno = ETIMEDOUT;
426 return (-1);
427 }
428