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 uchar_t *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 void *buf;
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 **)&buf, 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 = buf;
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 ip = buf;
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 }
260 #endif
261 free(ptr);
262 return (-1);
263 }
264 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
265 #ifdef NET_DEBUG
266 if (debug) {
267 printf("readip: bad saddr %s != ", inet_ntoa(d->myip));
268 printf("%s\n", inet_ntoa(ip->ip_dst));
269 }
270 #endif
271 free(ptr);
272 return (-1);
273 }
274
275 /* Unfragmented packet. */
276 if ((ntohs(ip->ip_off) & IP_MF) == 0 &&
277 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) {
278 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip));
279 /* If there were ip options, make them go away */
280 if (hlen != sizeof (*ip)) {
281 bcopy(((uchar_t *)ip) + hlen, uh, uh->uh_ulen - hlen);
282 ip->ip_len = htons(sizeof (*ip));
283 n -= hlen - sizeof (*ip);
284 }
285
286 n = (n > (ntohs(ip->ip_len) - sizeof (*ip))) ?
287 ntohs(ip->ip_len) - sizeof (*ip) : n;
288 *pkt = ptr;
289 *payload = (void *)((uintptr_t)ip + sizeof (*ip));
290 return (n);
291 }
292
293 STAILQ_FOREACH(ipr, &ire_list, ip_next) {
294 if (ipr->ip_src.s_addr == ip->ip_src.s_addr &&
295 ipr->ip_dst.s_addr == ip->ip_dst.s_addr &&
296 ipr->ip_id == ip->ip_id &&
297 ipr->ip_proto == ip->ip_p)
298 break;
299 }
300
301 /* Allocate new reassembly entry */
302 if (ipr == NULL) {
303 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) {
304 free(ptr);
305 return (-1);
306 }
307
308 ipr->ip_src = ip->ip_src;
309 ipr->ip_dst = ip->ip_dst;
310 ipr->ip_id = ip->ip_id;
311 ipr->ip_proto = ip->ip_p;
312 ipr->ip_ttl = MAXTTL;
313 STAILQ_INIT(&ipr->ip_queue);
314 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next);
315 }
316
317 if (ip_reasm_add(ipr, ptr, ip) != 0) {
318 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
319 free(ipr);
320 free(ptr);
321 return (-1);
322 }
323
324 if ((ntohs(ip->ip_off) & IP_MF) == 0) {
325 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK));
326 ipr->ip_total_size += n + sizeof (*ip);
327 ipr->ip_total_size += sizeof (struct ether_header);
328
329 ipr->ip_pkt = malloc(ipr->ip_total_size + 2);
330 if (ipr->ip_pkt == NULL) {
331 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
332 ip_reasm_free(ipr);
333 return (-1);
334 }
335 }
336
337 /*
338 * If we do not have re-assembly buffer ipr->ip_pkt, we are still
339 * missing fragments, so just restart the read.
340 */
341 if (ipr->ip_pkt == NULL) {
342 errno = EAGAIN;
343 return (-1);
344 }
345
346 /*
347 * Walk the packet list in reassembly queue, if we got all the
348 * fragments, build the packet.
349 */
350 n = 0;
351 last = NULL;
352 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
353 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) {
354 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next);
355 ip_reasm_free(ipr);
356 return (-1);
357 }
358
359 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2);
360 last = ipq;
361 }
362 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) {
363 errno = EAGAIN;
364 return (-1);
365 }
366
367 ipq = STAILQ_FIRST(&ipr->ip_queue);
368 /* Fabricate ethernet header */
369 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2);
370 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh));
371
372 /* Fabricate IP header */
373 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh));
374 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr));
375 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2;
376 ipr->ip_hdr->ip_len = htons(n);
377 ipr->ip_hdr->ip_sum = 0;
378 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr));
379
380 n = 0;
381 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr));
382 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) {
383 char *data;
384 size_t len;
385
386 hlen = ipq->ipq_hdr->ip_hl << 2;
387 len = ntohs(ipq->ipq_hdr->ip_len) - hlen;
388 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen);
389
390 bcopy(data, ptr + n, len);
391 n += len;
392 }
393
394 *pkt = ipr->ip_pkt;
395 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */
396 *payload = ptr;
397
398 /* Clean up the reassembly list */
399 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) {
400 STAILQ_REMOVE_HEAD(&ire_list, ip_next);
401 ip_reasm_free(ipr);
402 }
403 return (n);
404 }
405
406 /*
407 * Receive a IP packet.
408 */
409 ssize_t
readip(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,uint8_t proto)410 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft,
411 uint8_t proto)
412 {
413 time_t t;
414 ssize_t ret = -1;
415
416 t = getsecs();
417 while ((getsecs() - t) < tleft) {
418 errno = 0;
419 ret = readipv4(d, pkt, payload, tleft, proto);
420 if (ret >= 0)
421 return (ret);
422 /* Bubble up the error if it wasn't successful */
423 if (errno != EAGAIN)
424 return (-1);
425 }
426 /* We've exhausted tleft; timeout */
427 errno = ETIMEDOUT;
428 return (-1);
429 }
430