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/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 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 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 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 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 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