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 __FBSDID("$FreeBSD$");
42
43 #include <sys/param.h>
44 #include <sys/socket.h>
45 #include <sys/queue.h>
46
47 #include <string.h>
48
49 #include <net/if.h>
50 #include <netinet/in.h>
51 #include <netinet/if_ether.h>
52 #include <netinet/in_systm.h>
53
54 #include <netinet/in_pcb.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/udp.h>
58 #include <netinet/udp_var.h>
59
60 #include "stand.h"
61 #include "net.h"
62
63 typedef STAILQ_HEAD(ipqueue, ip_queue) ip_queue_t;
64 struct ip_queue {
65 void *ipq_pkt;
66 struct ip *ipq_hdr;
67 STAILQ_ENTRY(ip_queue) ipq_next;
68 };
69
70 /*
71 * Fragment re-assembly queue.
72 */
73 struct ip_reasm {
74 struct in_addr ip_src;
75 struct in_addr ip_dst;
76 uint16_t ip_id;
77 uint8_t ip_proto;
78 uint8_t ip_ttl;
79 size_t ip_total_size;
80 ip_queue_t ip_queue;
81 void *ip_pkt;
82 struct ip *ip_hdr;
83 STAILQ_ENTRY(ip_reasm) ip_next;
84 };
85
86 STAILQ_HEAD(ire_list, ip_reasm) ire_list = STAILQ_HEAD_INITIALIZER(ire_list);
87
88 /* Caller must leave room for ethernet and ip headers in front!! */
89 ssize_t
sendip(struct iodesc * d,void * pkt,size_t len,uint8_t proto)90 sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto)
91 {
92 ssize_t cc;
93 struct ip *ip;
94 u_char *ea;
95
96 #ifdef NET_DEBUG
97 if (debug) {
98 printf("sendip: proto: %x d=%p called.\n", proto, (void *)d);
99 if (d) {
100 printf("saddr: %s:%d",
101 inet_ntoa(d->myip), ntohs(d->myport));
102 printf(" daddr: %s:%d\n",
103 inet_ntoa(d->destip), ntohs(d->destport));
104 }
105 }
106 #endif
107
108 ip = (struct ip *)pkt - 1;
109 len += sizeof(*ip);
110
111 bzero(ip, sizeof(*ip));
112
113 ip->ip_v = IPVERSION; /* half-char */
114 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
115 ip->ip_len = htons(len);
116 ip->ip_p = proto; /* char */
117 ip->ip_ttl = IPDEFTTL; /* char */
118 ip->ip_src = d->myip;
119 ip->ip_dst = d->destip;
120 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
121
122 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
123 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
124 ea = arpwhohas(d, ip->ip_dst);
125 else
126 ea = arpwhohas(d, gateip);
127
128 cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
129 if (cc == -1)
130 return (-1);
131 if (cc != len)
132 panic("sendip: bad write (%zd != %zd)", cc, len);
133 return (cc - sizeof(*ip));
134 }
135
136 static void
ip_reasm_free(struct ip_reasm * ipr)137 ip_reasm_free(struct ip_reasm *ipr)
138 {
139 struct ip_queue *ipq;
140
141 while ((ipq = STAILQ_FIRST(&ipr->ip_queue)) != NULL) {
142 STAILQ_REMOVE_HEAD(&ipr->ip_queue, ipq_next);
143 free(ipq->ipq_pkt);
144 free(ipq);
145 }
146 free(ipr->ip_pkt);
147 free(ipr);
148 }
149
150 static int
ip_reasm_add(struct ip_reasm * ipr,void * pkt,struct ip * ip)151 ip_reasm_add(struct ip_reasm *ipr, void *pkt, struct ip *ip)
152 {
153 struct ip_queue *ipq, *prev, *p;
154
155 if ((ipq = calloc(1, sizeof (*ipq))) == NULL)
156 return (1);
157
158 ipq->ipq_pkt = pkt;
159 ipq->ipq_hdr = ip;
160
161 prev = NULL;
162 STAILQ_FOREACH(p, &ipr->ip_queue, ipq_next) {
163 if ((ntohs(p->ipq_hdr->ip_off) & IP_OFFMASK) <
164 (ntohs(ip->ip_off) & IP_OFFMASK)) {
165 prev = p;
166 continue;
167 }
168 if (prev == NULL)
169 break;
170
171 STAILQ_INSERT_AFTER(&ipr->ip_queue, prev, ipq, ipq_next);
172 return (0);
173 }
174 STAILQ_INSERT_HEAD(&ipr->ip_queue, ipq, ipq_next);
175 return (0);
176 }
177
178 /*
179 * Receive a IP packet and validate it is for us.
180 */
181 static ssize_t
readipv4(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)182 readipv4(struct iodesc *d, void **pkt, void **payload, time_t tleft,
183 uint8_t proto)
184 {
185 ssize_t n;
186 size_t hlen;
187 struct ether_header *eh;
188 struct ip *ip;
189 struct udphdr *uh;
190 uint16_t etype; /* host order */
191 char *ptr;
192 struct ip_reasm *ipr;
193 struct ip_queue *ipq, *last;
194
195 #ifdef NET_DEBUG
196 if (debug)
197 printf("readip: called\n");
198 #endif
199
200 ip = NULL;
201 ptr = NULL;
202 n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype);
203 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) {
204 free(ptr);
205 return (-1);
206 }
207
208 /* Ethernet address checks now in readether() */
209
210 /* Need to respond to ARP requests. */
211 if (etype == ETHERTYPE_ARP) {
212 struct arphdr *ah = (void *)ip;
213 if (ah->ar_op == htons(ARPOP_REQUEST)) {
214 /* Send ARP reply */
215 arp_reply(d, ah);
216 }
217 free(ptr);
218 errno = EAGAIN; /* Call me again. */
219 return (-1);
220 }
221
222 if (etype != ETHERTYPE_IP) {
223 #ifdef NET_DEBUG
224 if (debug)
225 printf("readip: not IP. ether_type=%x\n", etype);
226 #endif
227 free(ptr);
228 return (-1);
229 }
230
231 /* Check ip header */
232 if (ip->ip_v != IPVERSION || /* half char */
233 ip->ip_p != proto) {
234 #ifdef NET_DEBUG
235 if (debug) {
236 printf("readip: IP version or proto. ip_v=%d ip_p=%d\n",
237 ip->ip_v, ip->ip_p);
238 }
239 #endif
240 free(ptr);
241 return (-1);
242 }
243
244 hlen = ip->ip_hl << 2;
245 if (hlen < sizeof(*ip) ||
246 in_cksum(ip, hlen) != 0) {
247 #ifdef NET_DEBUG
248 if (debug)
249 printf("readip: short hdr or bad cksum.\n");
250 #endif
251 free(ptr);
252 return (-1);
253 }
254 if (n < ntohs(ip->ip_len)) {
255 #ifdef NET_DEBUG
256 if (debug)
257 printf("readip: bad length %d < %d.\n",
258 (int)n, ntohs(ip->ip_len));
259 #endif
260 free(ptr);
261 return (-1);
262 }
263 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
264 #ifdef NET_DEBUG
265 if (debug) {
266 printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
267 printf("%s\n", inet_ntoa(ip->ip_dst));
268 }
269 #endif
270 free(ptr);
271 return (-1);
272 }
273
274 /* Unfragmented packet. */
275 if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
276 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
277 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
278 /* If there were ip options, make them go away */
279 if (hlen != sizeof(*ip)) {
280 bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen);
281 ip->ip_len = htons(sizeof(*ip));
282 n -= hlen - sizeof(*ip);
283 }
284
285 n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ?
286 ntohs(ip->ip_len) - sizeof(*ip) : n;
287 *pkt = ptr;
288 *payload = (void *)((uintptr_t)ip + sizeof(*ip));
289 return (n);
290 }
291
292 STAILQ_FOREACH(ipr, &ire_list, ip_next) {
293 if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
294 ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
295 ipr->ip_id == ip->ip_id &&
296 ipr->ip_proto == ip->ip_p)
297 break;
298 }
299
300 /* Allocate new reassembly entry */
301 if (ipr == NULL) {
302 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
303 free(ptr);
304 return (-1);
305 }
306
307 ipr->ip_src = ip->ip_src;
308 ipr->ip_dst = ip->ip_dst;
309 ipr->ip_id = ip->ip_id;
310 ipr->ip_proto = ip->ip_p;
311 ipr->ip_ttl = MAXTTL;
312 STAILQ_INIT(&ipr->ip_queue);
313 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
314 }
315
316 if (ip_reasm_add(ipr, ptr, ip) != 0) {
317 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
318 free(ipr);
319 free(ptr);
320 return (-1);
321 }
322
323 if ((ntohs(ip->ip_off) & IP_MF) == 0) {
324 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
325 ipr->ip_total_size += n + sizeof (*ip);
326 ipr->ip_total_size += sizeof (struct ether_header);
327
328 ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
329 if (ipr->ip_pkt == NULL) {
330 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
331 ip_reasm_free(ipr);
332 return (-1);
333 }
334 }
335
336 /*
337 * If we do not have re-assembly buffer ipr->ip_pkt, we are still
338 * missing fragments, so just restart the read.
339 */
340 if (ipr->ip_pkt == NULL) {
341 errno = EAGAIN;
342 return (-1);
343 }
344
345 /*
346 * Walk the packet list in reassembly queue, if we got all the
347 * fragments, build the packet.
348 */
349 n = 0;
350 last = NULL;
351 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
352 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
353 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
354 ip_reasm_free(ipr);
355 return (-1);
356 }
357
358 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
359 last = ipq;
360 }
361 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
362 errno = EAGAIN;
363 return (-1);
364 }
365
366 ipq = STAILQ_FIRST(&ipr->ip_queue);
367 /* Fabricate ethernet header */
368 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
369 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
370
371 /* Fabricate IP header */
372 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
373 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
374 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
375 ipr->ip_hdr->ip_len = htons(n);
376 ipr->ip_hdr->ip_sum = 0;
377 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
378
379 n = 0;
380 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
381 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
382 char *data;
383 size_t len;
384
385 hlen = ipq->ipq_hdr->ip_hl << 2;
386 len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
387 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
388
389 bcopy(data, ptr + n, len);
390 n += len;
391 }
392
393 *pkt = ipr->ip_pkt;
394 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
395 *payload = ptr;
396
397 /* Clean up the reassembly list */
398 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
399 STAILQ_REMOVE_HEAD(&ire_list, ip_next);
400 ip_reasm_free(ipr);
401 }
402 return (n);
403 }
404
405 /*
406 * Receive a IP packet.
407 */
408 ssize_t
readip(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)409 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
410 uint8_t proto)
411 {
412 time_t t;
413 ssize_t ret = -1;
414
415 t = getsecs();
416 while ((getsecs() - t) < tleft) {
417 errno = 0;
418 ret = readipv4(d, pkt, payload, tleft, proto);
419 if (ret >= 0)
420 return (ret);
421 /* Bubble up the error if it wasn't successful */
422 if (errno != EAGAIN)
423 return (-1);
424 }
425 /* We've exhausted tleft; timeout */
426 errno = ETIMEDOUT;
427 return (-1);
428 }
429