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