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 88 sendip(struct iodesc *d, void *pkt, size_t len, uint8_t proto) 89 { 90 ssize_t cc; 91 struct ip *ip; 92 u_char *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 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 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 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 struct ip *ip; 187 struct udphdr *uh; 188 uint16_t etype; /* host order */ 189 char *ptr; 190 struct ip_reasm *ipr; 191 struct ip_queue *ipq, *last; 192 193 #ifdef NET_DEBUG 194 if (debug) 195 printf("readip: called\n"); 196 #endif 197 198 ip = NULL; 199 ptr = NULL; 200 n = readether(d, (void **)&ptr, (void **)&ip, tleft, &etype); 201 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) { 202 free(ptr); 203 return (-1); 204 } 205 206 /* Ethernet address checks now in readether() */ 207 208 /* Need to respond to ARP requests. */ 209 if (etype == ETHERTYPE_ARP) { 210 struct arphdr *ah = (void *)ip; 211 if (ah->ar_op == htons(ARPOP_REQUEST)) { 212 /* Send ARP reply */ 213 arp_reply(d, ah); 214 } 215 free(ptr); 216 errno = EAGAIN; /* Call me again. */ 217 return (-1); 218 } 219 220 if (etype != ETHERTYPE_IP) { 221 #ifdef NET_DEBUG 222 if (debug) 223 printf("readip: not IP. ether_type=%x\n", etype); 224 #endif 225 free(ptr); 226 return (-1); 227 } 228 229 /* Check ip header */ 230 if (ip->ip_v != IPVERSION || /* half char */ 231 ip->ip_p != proto) { 232 #ifdef NET_DEBUG 233 if (debug) { 234 printf("readip: IP version or proto. ip_v=%d ip_p=%d\n", 235 ip->ip_v, ip->ip_p); 236 } 237 #endif 238 free(ptr); 239 return (-1); 240 } 241 242 hlen = ip->ip_hl << 2; 243 if (hlen < sizeof(*ip) || 244 in_cksum(ip, hlen) != 0) { 245 #ifdef NET_DEBUG 246 if (debug) 247 printf("readip: short hdr or bad cksum.\n"); 248 #endif 249 free(ptr); 250 return (-1); 251 } 252 if (n < ntohs(ip->ip_len)) { 253 #ifdef NET_DEBUG 254 if (debug) 255 printf("readip: bad length %d < %d.\n", 256 (int)n, ntohs(ip->ip_len)); 257 #endif 258 free(ptr); 259 return (-1); 260 } 261 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) { 262 #ifdef NET_DEBUG 263 if (debug) { 264 printf("readip: bad saddr %s != ", inet_ntoa(d->myip)); 265 printf("%s\n", inet_ntoa(ip->ip_dst)); 266 } 267 #endif 268 free(ptr); 269 return (-1); 270 } 271 272 /* Unfragmented packet. */ 273 if ((ntohs(ip->ip_off) & IP_MF) == 0 && 274 (ntohs(ip->ip_off) & IP_OFFMASK) == 0) { 275 uh = (struct udphdr *)((uintptr_t)ip + sizeof (*ip)); 276 /* If there were ip options, make them go away */ 277 if (hlen != sizeof(*ip)) { 278 bcopy(((u_char *)ip) + hlen, uh, uh->uh_ulen - hlen); 279 ip->ip_len = htons(sizeof(*ip)); 280 n -= hlen - sizeof(*ip); 281 } 282 283 n = (n > (ntohs(ip->ip_len) - sizeof(*ip))) ? 284 ntohs(ip->ip_len) - sizeof(*ip) : n; 285 *pkt = ptr; 286 *payload = (void *)((uintptr_t)ip + sizeof(*ip)); 287 return (n); 288 } 289 290 STAILQ_FOREACH(ipr, &ire_list, ip_next) { 291 if (ipr->ip_src.s_addr == ip->ip_src.s_addr && 292 ipr->ip_dst.s_addr == ip->ip_dst.s_addr && 293 ipr->ip_id == ip->ip_id && 294 ipr->ip_proto == ip->ip_p) 295 break; 296 } 297 298 /* Allocate new reassembly entry */ 299 if (ipr == NULL) { 300 if ((ipr = calloc(1, sizeof (*ipr))) == NULL) { 301 free(ptr); 302 return (-1); 303 } 304 305 ipr->ip_src = ip->ip_src; 306 ipr->ip_dst = ip->ip_dst; 307 ipr->ip_id = ip->ip_id; 308 ipr->ip_proto = ip->ip_p; 309 ipr->ip_ttl = MAXTTL; 310 STAILQ_INIT(&ipr->ip_queue); 311 STAILQ_INSERT_TAIL(&ire_list, ipr, ip_next); 312 } 313 314 if (ip_reasm_add(ipr, ptr, ip) != 0) { 315 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next); 316 free(ipr); 317 free(ptr); 318 return (-1); 319 } 320 321 if ((ntohs(ip->ip_off) & IP_MF) == 0) { 322 ipr->ip_total_size = (8 * (ntohs(ip->ip_off) & IP_OFFMASK)); 323 ipr->ip_total_size += n + sizeof (*ip); 324 ipr->ip_total_size += sizeof (struct ether_header); 325 326 ipr->ip_pkt = malloc(ipr->ip_total_size + 2); 327 if (ipr->ip_pkt == NULL) { 328 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next); 329 ip_reasm_free(ipr); 330 return (-1); 331 } 332 } 333 334 /* 335 * If we do not have re-assembly buffer ipr->ip_pkt, we are still 336 * missing fragments, so just restart the read. 337 */ 338 if (ipr->ip_pkt == NULL) { 339 errno = EAGAIN; 340 return (-1); 341 } 342 343 /* 344 * Walk the packet list in reassembly queue, if we got all the 345 * fragments, build the packet. 346 */ 347 n = 0; 348 last = NULL; 349 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) { 350 if ((ntohs(ipq->ipq_hdr->ip_off) & IP_OFFMASK) != n / 8) { 351 STAILQ_REMOVE(&ire_list, ipr, ip_reasm, ip_next); 352 ip_reasm_free(ipr); 353 return (-1); 354 } 355 356 n += ntohs(ipq->ipq_hdr->ip_len) - (ipq->ipq_hdr->ip_hl << 2); 357 last = ipq; 358 } 359 if ((ntohs(last->ipq_hdr->ip_off) & IP_MF) != 0) { 360 errno = EAGAIN; 361 return (-1); 362 } 363 364 ipq = STAILQ_FIRST(&ipr->ip_queue); 365 /* Fabricate ethernet header */ 366 eh = (struct ether_header *)((uintptr_t)ipr->ip_pkt + 2); 367 bcopy((void *)((uintptr_t)ipq->ipq_pkt + 2), eh, sizeof (*eh)); 368 369 /* Fabricate IP header */ 370 ipr->ip_hdr = (struct ip *)((uintptr_t)eh + sizeof (*eh)); 371 bcopy(ipq->ipq_hdr, ipr->ip_hdr, sizeof (*ipr->ip_hdr)); 372 ipr->ip_hdr->ip_hl = sizeof (*ipr->ip_hdr) >> 2; 373 ipr->ip_hdr->ip_len = htons(n); 374 ipr->ip_hdr->ip_sum = 0; 375 ipr->ip_hdr->ip_sum = in_cksum(ipr->ip_hdr, sizeof (*ipr->ip_hdr)); 376 377 n = 0; 378 ptr = (char *)((uintptr_t)ipr->ip_hdr + sizeof (*ipr->ip_hdr)); 379 STAILQ_FOREACH(ipq, &ipr->ip_queue, ipq_next) { 380 char *data; 381 size_t len; 382 383 hlen = ipq->ipq_hdr->ip_hl << 2; 384 len = ntohs(ipq->ipq_hdr->ip_len) - hlen; 385 data = (char *)((uintptr_t)ipq->ipq_hdr + hlen); 386 387 bcopy(data, ptr + n, len); 388 n += len; 389 } 390 391 *pkt = ipr->ip_pkt; 392 ipr->ip_pkt = NULL; /* Avoid free from ip_reasm_free() */ 393 *payload = ptr; 394 395 /* Clean up the reassembly list */ 396 while ((ipr = STAILQ_FIRST(&ire_list)) != NULL) { 397 STAILQ_REMOVE_HEAD(&ire_list, ip_next); 398 ip_reasm_free(ipr); 399 } 400 return (n); 401 } 402 403 /* 404 * Receive a IP packet. 405 */ 406 ssize_t 407 readip(struct iodesc *d, void **pkt, void **payload, time_t tleft, 408 uint8_t proto) 409 { 410 time_t t; 411 ssize_t ret = -1; 412 413 t = getsecs(); 414 while ((getsecs() - t) < tleft) { 415 errno = 0; 416 ret = readipv4(d, pkt, payload, tleft, proto); 417 if (ret >= 0) 418 return (ret); 419 /* Bubble up the error if it wasn't successful */ 420 if (errno != EAGAIN) 421 return (-1); 422 } 423 /* We've exhausted tleft; timeout */ 424 errno = ETIMEDOUT; 425 return (-1); 426 } 427