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 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 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 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 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 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