1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. 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 * from: @(#)ip_output.c 7.23 (Berkeley) 11/12/90 34 * $Id: ip_output.c,v 1.4 1993/11/05 23:06:26 cgd Exp $ 35 */ 36 37 #include "param.h" 38 #include "malloc.h" 39 #include "mbuf.h" 40 #include "errno.h" 41 #include "protosw.h" 42 #include "socket.h" 43 #include "socketvar.h" 44 45 #include "../net/if.h" 46 #include "../net/route.h" 47 48 #include "in.h" 49 #include "in_systm.h" 50 #include "ip.h" 51 #include "in_pcb.h" 52 #include "in_var.h" 53 #include "ip_var.h" 54 55 #ifdef vax 56 #include "machine/mtpr.h" 57 #endif 58 59 struct mbuf *ip_insertoptions(); 60 61 /* 62 * IP output. The packet in mbuf chain m contains a skeletal IP 63 * header (with len, off, ttl, proto, tos, src, dst). 64 * The mbuf chain containing the packet will be freed. 65 * The mbuf opt, if present, will not be freed. 66 */ 67 ip_output(m0, opt, ro, flags) 68 struct mbuf *m0; 69 struct mbuf *opt; 70 struct route *ro; 71 int flags; 72 { 73 register struct ip *ip, *mhip; 74 register struct ifnet *ifp; 75 register struct mbuf *m = m0; 76 register int hlen = sizeof (struct ip); 77 int len, off, error = 0; 78 struct route iproute; 79 struct sockaddr_in *dst; 80 struct in_ifaddr *ia; 81 82 #ifdef DIAGNOSTIC 83 if ((m->m_flags & M_PKTHDR) == 0) 84 panic("ip_output no HDR"); 85 #endif 86 if (opt) { 87 m = ip_insertoptions(m, opt, &len); 88 hlen = len; 89 } 90 ip = mtod(m, struct ip *); 91 /* 92 * Fill in IP header. 93 */ 94 if ((flags & IP_FORWARDING) == 0) { 95 ip->ip_v = IPVERSION; 96 ip->ip_off &= IP_DF; 97 ip->ip_id = htons(ip_id++); 98 ip->ip_hl = hlen >> 2; 99 } else { 100 hlen = ip->ip_hl << 2; 101 ipstat.ips_localout++; 102 } 103 /* 104 * Route packet. 105 */ 106 if (ro == 0) { 107 ro = &iproute; 108 bzero((caddr_t)ro, sizeof (*ro)); 109 } 110 dst = (struct sockaddr_in *)&ro->ro_dst; 111 /* 112 * If there is a cached route, 113 * check that it is to the same destination 114 * and is still up. If not, free it and try again. 115 */ 116 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 117 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 118 RTFREE(ro->ro_rt); 119 ro->ro_rt = (struct rtentry *)0; 120 } 121 if (ro->ro_rt == 0) { 122 dst->sin_family = AF_INET; 123 dst->sin_len = sizeof(*dst); 124 dst->sin_addr = ip->ip_dst; 125 } 126 /* 127 * If routing to interface only, 128 * short circuit routing lookup. 129 */ 130 if (flags & IP_ROUTETOIF) { 131 132 ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst); 133 if (ia == 0) 134 ia = in_iaonnetof(in_netof(ip->ip_dst)); 135 if (ia == 0) { 136 error = ENETUNREACH; 137 goto bad; 138 } 139 ifp = ia->ia_ifp; 140 } else { 141 if (ro->ro_rt == 0) 142 rtalloc(ro); 143 if (ro->ro_rt == 0) { 144 error = EHOSTUNREACH; 145 goto bad; 146 } 147 ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa; 148 ifp = ro->ro_rt->rt_ifp; 149 ro->ro_rt->rt_use++; 150 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 151 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 152 } 153 #ifndef notdef 154 /* 155 * If source address not specified yet, use address 156 * of outgoing interface. 157 */ 158 if (ip->ip_src.s_addr == INADDR_ANY) 159 ip->ip_src = IA_SIN(ia)->sin_addr; 160 #endif 161 162 /* 163 * Verify that we have any chance at all of being able to queue 164 * the packet or packet fragments 165 */ 166 if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 167 ifp->if_snd.ifq_maxlen) { 168 error = ENOBUFS; 169 goto bad; 170 } 171 172 /* 173 * Look for broadcast address and 174 * and verify user is allowed to send 175 * such a packet. 176 */ 177 if (in_broadcast(dst->sin_addr)) { 178 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 179 error = EADDRNOTAVAIL; 180 goto bad; 181 } 182 if ((flags & IP_ALLOWBROADCAST) == 0) { 183 error = EACCES; 184 goto bad; 185 } 186 /* don't allow broadcast messages to be fragmented */ 187 if ((u_short)ip->ip_len > ifp->if_mtu) { 188 error = EMSGSIZE; 189 goto bad; 190 } 191 m->m_flags |= M_BCAST; 192 } 193 194 /* 195 * If small enough for interface, can just send directly. 196 */ 197 if ((u_short)ip->ip_len <= ifp->if_mtu) { 198 ip->ip_len = htons((u_short)ip->ip_len); 199 ip->ip_off = htons((u_short)ip->ip_off); 200 ip->ip_sum = 0; 201 ip->ip_sum = in_cksum(m, hlen); 202 error = (*ifp->if_output)(ifp, m, 203 (struct sockaddr *)dst, ro->ro_rt); 204 goto done; 205 } 206 ipstat.ips_fragmented++; 207 /* 208 * Too large for interface; fragment if possible. 209 * Must be able to put at least 8 bytes per fragment. 210 */ 211 if (ip->ip_off & IP_DF) { 212 error = EMSGSIZE; 213 goto bad; 214 } 215 len = (ifp->if_mtu - hlen) &~ 7; 216 if (len < 8) { 217 error = EMSGSIZE; 218 goto bad; 219 } 220 221 { 222 int mhlen, firstlen = len; 223 struct mbuf **mnext = &m->m_nextpkt; 224 225 /* 226 * Loop through length of segment after first fragment, 227 * make new header and copy data of each part and link onto chain. 228 */ 229 m0 = m; 230 mhlen = sizeof (struct ip); 231 for (off = hlen + len; off < (u_short)ip->ip_len; off += len) { 232 MGETHDR(m, M_DONTWAIT, MT_HEADER); 233 if (m == 0) { 234 error = ENOBUFS; 235 goto sendorfree; 236 } 237 m->m_data += max_linkhdr; 238 mhip = mtod(m, struct ip *); 239 *mhip = *ip; 240 if (hlen > sizeof (struct ip)) { 241 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 242 mhip->ip_hl = mhlen >> 2; 243 } 244 m->m_len = mhlen; 245 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 246 if (ip->ip_off & IP_MF) 247 mhip->ip_off |= IP_MF; 248 if (off + len >= (u_short)ip->ip_len) 249 len = (u_short)ip->ip_len - off; 250 else 251 mhip->ip_off |= IP_MF; 252 mhip->ip_len = htons((u_short)(len + mhlen)); 253 m->m_next = m_copy(m0, off, len); 254 if (m->m_next == 0) { 255 error = ENOBUFS; /* ??? */ 256 goto sendorfree; 257 } 258 m->m_pkthdr.len = mhlen + len; 259 m->m_pkthdr.rcvif = (struct ifnet *)0; 260 mhip->ip_off = htons((u_short)mhip->ip_off); 261 mhip->ip_sum = 0; 262 mhip->ip_sum = in_cksum(m, mhlen); 263 *mnext = m; 264 mnext = &m->m_nextpkt; 265 ipstat.ips_ofragments++; 266 } 267 /* 268 * Update first fragment by trimming what's been copied out 269 * and updating header, then send each fragment (in order). 270 */ 271 m = m0; 272 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 273 m->m_pkthdr.len = hlen + firstlen; 274 ip->ip_len = htons((u_short)m->m_pkthdr.len); 275 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 276 ip->ip_sum = 0; 277 ip->ip_sum = in_cksum(m, hlen); 278 sendorfree: 279 for (m = m0; m; m = m0) { 280 m0 = m->m_nextpkt; 281 m->m_nextpkt = 0; 282 if (error == 0) 283 error = (*ifp->if_output)(ifp, m, 284 (struct sockaddr *)dst, ro->ro_rt); 285 else 286 m_freem(m); 287 } 288 } 289 done: 290 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 291 RTFREE(ro->ro_rt); 292 return (error); 293 bad: 294 m_freem(m0); 295 goto done; 296 } 297 298 /* 299 * Insert IP options into preformed packet. 300 * Adjust IP destination as required for IP source routing, 301 * as indicated by a non-zero in_addr at the start of the options. 302 */ 303 struct mbuf * 304 ip_insertoptions(m, opt, phlen) 305 register struct mbuf *m; 306 struct mbuf *opt; 307 int *phlen; 308 { 309 register struct ipoption *p = mtod(opt, struct ipoption *); 310 struct mbuf *n; 311 register struct ip *ip = mtod(m, struct ip *); 312 unsigned optlen; 313 314 optlen = opt->m_len - sizeof(p->ipopt_dst); 315 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 316 return (m); /* XXX should fail */ 317 if (p->ipopt_dst.s_addr) 318 ip->ip_dst = p->ipopt_dst; 319 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 320 MGETHDR(n, M_DONTWAIT, MT_HEADER); 321 if (n == 0) 322 return (m); 323 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 324 m->m_len -= sizeof(struct ip); 325 m->m_data += sizeof(struct ip); 326 n->m_next = m; 327 m = n; 328 m->m_len = optlen + sizeof(struct ip); 329 m->m_data += max_linkhdr; 330 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 331 } else { 332 m->m_data -= optlen; 333 m->m_len += optlen; 334 m->m_pkthdr.len += optlen; 335 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 336 } 337 ip = mtod(m, struct ip *); 338 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 339 *phlen = sizeof(struct ip) + optlen; 340 ip->ip_len += optlen; 341 return (m); 342 } 343 344 /* 345 * Copy options from ip to jp, 346 * omitting those not copied during fragmentation. 347 */ 348 ip_optcopy(ip, jp) 349 struct ip *ip, *jp; 350 { 351 register u_char *cp, *dp; 352 int opt, optlen, cnt; 353 354 cp = (u_char *)(ip + 1); 355 dp = (u_char *)(jp + 1); 356 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 357 for (; cnt > 0; cnt -= optlen, cp += optlen) { 358 opt = cp[0]; 359 if (opt == IPOPT_EOL) 360 break; 361 if (opt == IPOPT_NOP) 362 optlen = 1; 363 else 364 optlen = cp[IPOPT_OLEN]; 365 /* bogus lengths should have been caught by ip_dooptions */ 366 if (optlen > cnt) 367 optlen = cnt; 368 if (IPOPT_COPIED(opt)) { 369 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 370 dp += optlen; 371 } 372 } 373 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 374 *dp++ = IPOPT_EOL; 375 return (optlen); 376 } 377 378 /* 379 * IP socket option processing. 380 */ 381 ip_ctloutput(op, so, level, optname, mp) 382 int op; 383 struct socket *so; 384 int level, optname; 385 struct mbuf **mp; 386 { 387 register struct inpcb *inp = sotoinpcb(so); 388 register struct mbuf *m = *mp; 389 register int optval; 390 int error = 0; 391 392 if (level != IPPROTO_IP) 393 error = EINVAL; 394 else switch (op) { 395 396 case PRCO_SETOPT: 397 switch (optname) { 398 case IP_OPTIONS: 399 #ifdef notyet 400 case IP_RETOPTS: 401 return (ip_pcbopts(optname, &inp->inp_options, m)); 402 #else 403 return (ip_pcbopts(&inp->inp_options, m)); 404 #endif 405 406 case IP_TOS: 407 case IP_TTL: 408 case IP_RECVOPTS: 409 case IP_RECVRETOPTS: 410 case IP_RECVDSTADDR: 411 if (m->m_len != sizeof(int)) 412 error = EINVAL; 413 else { 414 optval = *mtod(m, int *); 415 switch (optname) { 416 417 case IP_TOS: 418 inp->inp_ip.ip_tos = optval; 419 break; 420 421 case IP_TTL: 422 inp->inp_ip.ip_ttl = optval; 423 break; 424 #define OPTSET(bit) \ 425 if (optval) \ 426 inp->inp_flags |= bit; \ 427 else \ 428 inp->inp_flags &= ~bit; 429 430 case IP_RECVOPTS: 431 OPTSET(INP_RECVOPTS); 432 break; 433 434 case IP_RECVRETOPTS: 435 OPTSET(INP_RECVRETOPTS); 436 break; 437 438 case IP_RECVDSTADDR: 439 OPTSET(INP_RECVDSTADDR); 440 break; 441 } 442 } 443 break; 444 #undef OPTSET 445 446 default: 447 error = EINVAL; 448 break; 449 } 450 if (m) 451 (void)m_free(m); 452 break; 453 454 case PRCO_GETOPT: 455 switch (optname) { 456 case IP_OPTIONS: 457 case IP_RETOPTS: 458 *mp = m = m_get(M_WAIT, MT_SOOPTS); 459 if (inp->inp_options) { 460 m->m_len = inp->inp_options->m_len; 461 bcopy(mtod(inp->inp_options, caddr_t), 462 mtod(m, caddr_t), (unsigned)m->m_len); 463 } else 464 m->m_len = 0; 465 break; 466 467 case IP_TOS: 468 case IP_TTL: 469 case IP_RECVOPTS: 470 case IP_RECVRETOPTS: 471 case IP_RECVDSTADDR: 472 *mp = m = m_get(M_WAIT, MT_SOOPTS); 473 m->m_len = sizeof(int); 474 switch (optname) { 475 476 case IP_TOS: 477 optval = inp->inp_ip.ip_tos; 478 break; 479 480 case IP_TTL: 481 optval = inp->inp_ip.ip_ttl; 482 break; 483 484 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 485 486 case IP_RECVOPTS: 487 optval = OPTBIT(INP_RECVOPTS); 488 break; 489 490 case IP_RECVRETOPTS: 491 optval = OPTBIT(INP_RECVRETOPTS); 492 break; 493 494 case IP_RECVDSTADDR: 495 optval = OPTBIT(INP_RECVDSTADDR); 496 break; 497 } 498 *mtod(m, int *) = optval; 499 break; 500 501 default: 502 error = EINVAL; 503 break; 504 } 505 break; 506 } 507 return (error); 508 } 509 510 /* 511 * Set up IP options in pcb for insertion in output packets. 512 * Store in mbuf with pointer in pcbopt, adding pseudo-option 513 * with destination address if source routed. 514 */ 515 #ifdef notyet 516 ip_pcbopts(optname, pcbopt, m) 517 int optname; 518 #else 519 ip_pcbopts(pcbopt, m) 520 #endif 521 struct mbuf **pcbopt; 522 register struct mbuf *m; 523 { 524 register cnt, optlen; 525 register u_char *cp; 526 u_char opt; 527 528 /* turn off any old options */ 529 if (*pcbopt) 530 (void)m_free(*pcbopt); 531 *pcbopt = 0; 532 if (m == (struct mbuf *)0 || m->m_len == 0) { 533 /* 534 * Only turning off any previous options. 535 */ 536 if (m) 537 (void)m_free(m); 538 return (0); 539 } 540 541 #ifndef vax 542 if (m->m_len % sizeof(long)) 543 goto bad; 544 #endif 545 /* 546 * IP first-hop destination address will be stored before 547 * actual options; move other options back 548 * and clear it when none present. 549 */ 550 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 551 goto bad; 552 cnt = m->m_len; 553 m->m_len += sizeof(struct in_addr); 554 cp = mtod(m, u_char *) + sizeof(struct in_addr); 555 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 556 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 557 558 for (; cnt > 0; cnt -= optlen, cp += optlen) { 559 opt = cp[IPOPT_OPTVAL]; 560 if (opt == IPOPT_EOL) 561 break; 562 if (opt == IPOPT_NOP) 563 optlen = 1; 564 else { 565 optlen = cp[IPOPT_OLEN]; 566 if (optlen <= IPOPT_OLEN || optlen > cnt) 567 goto bad; 568 } 569 switch (opt) { 570 571 default: 572 break; 573 574 case IPOPT_LSRR: 575 case IPOPT_SSRR: 576 /* 577 * user process specifies route as: 578 * ->A->B->C->D 579 * D must be our final destination (but we can't 580 * check that since we may not have connected yet). 581 * A is first hop destination, which doesn't appear in 582 * actual IP option, but is stored before the options. 583 */ 584 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 585 goto bad; 586 m->m_len -= sizeof(struct in_addr); 587 cnt -= sizeof(struct in_addr); 588 optlen -= sizeof(struct in_addr); 589 cp[IPOPT_OLEN] = optlen; 590 /* 591 * Move first hop before start of options. 592 */ 593 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 594 sizeof(struct in_addr)); 595 /* 596 * Then copy rest of options back 597 * to close up the deleted entry. 598 */ 599 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 600 sizeof(struct in_addr)), 601 (caddr_t)&cp[IPOPT_OFFSET+1], 602 (unsigned)cnt + sizeof(struct in_addr)); 603 break; 604 } 605 } 606 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 607 goto bad; 608 *pcbopt = m; 609 return (0); 610 611 bad: 612 (void)m_free(m); 613 return (EINVAL); 614 } 615