1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that this notice is preserved and that due credit is given 7 * to the University of California at Berkeley. The name of the University 8 * may not be used to endorse or promote products derived from this 9 * software without specific prior written permission. This software 10 * is provided ``as is'' without express or implied warranty. 11 * 12 * @(#)ip_output.c 7.11 (Berkeley) 05/26/88 13 */ 14 15 #include "param.h" 16 #include "mbuf.h" 17 #include "errno.h" 18 #include "protosw.h" 19 #include "socket.h" 20 #include "socketvar.h" 21 22 #include "../net/if.h" 23 #include "../net/route.h" 24 25 #include "in.h" 26 #include "in_pcb.h" 27 #include "in_systm.h" 28 #include "in_var.h" 29 #include "ip.h" 30 #include "ip_var.h" 31 32 #ifdef vax 33 #include "../machine/mtpr.h" 34 #endif 35 36 struct mbuf *ip_insertoptions(); 37 38 /* 39 * IP output. The packet in mbuf chain m contains a skeletal IP 40 * header (with len, off, ttl, proto, tos, src, dst). 41 * The mbuf chain containing the packet will be freed. 42 * The mbuf opt, if present, will not be freed. 43 */ 44 ip_output(m0, opt, ro, flags) 45 struct mbuf *m0; 46 struct mbuf *opt; 47 struct route *ro; 48 int flags; 49 { 50 register struct ip *ip, *mhip; 51 register struct ifnet *ifp; 52 register struct mbuf *m = m0; 53 register int hlen = sizeof (struct ip); 54 int len, off, error = 0; 55 struct route iproute; 56 struct sockaddr_in *dst; 57 58 if (opt) { 59 m = ip_insertoptions(m, opt, &len); 60 hlen = len; 61 } 62 ip = mtod(m, struct ip *); 63 /* 64 * Fill in IP header. 65 */ 66 if ((flags & IP_FORWARDING) == 0) { 67 ip->ip_v = IPVERSION; 68 ip->ip_off &= IP_DF; 69 ip->ip_id = htons(ip_id++); 70 ip->ip_hl = hlen >> 2; 71 } else 72 hlen = ip->ip_hl << 2; 73 74 /* 75 * Route packet. 76 */ 77 if (ro == 0) { 78 ro = &iproute; 79 bzero((caddr_t)ro, sizeof (*ro)); 80 } 81 dst = (struct sockaddr_in *)&ro->ro_dst; 82 /* 83 * If there is a cached route, 84 * check that it is to the same destination 85 * and is still up. If not, free it and try again. 86 */ 87 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 88 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 89 RTFREE(ro->ro_rt); 90 ro->ro_rt = (struct rtentry *)0; 91 } 92 if (ro->ro_rt == 0) { 93 dst->sin_family = AF_INET; 94 dst->sin_addr = ip->ip_dst; 95 } 96 /* 97 * If routing to interface only, 98 * short circuit routing lookup. 99 */ 100 if (flags & IP_ROUTETOIF) { 101 struct in_ifaddr *ia; 102 103 ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst); 104 if (ia == 0) 105 ia = in_iaonnetof(in_netof(ip->ip_dst)); 106 if (ia == 0) { 107 error = ENETUNREACH; 108 goto bad; 109 } 110 ifp = ia->ia_ifp; 111 } else { 112 if (ro->ro_rt == 0) 113 rtalloc(ro); 114 if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) { 115 if (in_localaddr(ip->ip_dst)) 116 error = EHOSTUNREACH; 117 else 118 error = ENETUNREACH; 119 goto bad; 120 } 121 ro->ro_rt->rt_use++; 122 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 123 dst = (struct sockaddr_in *)&ro->ro_rt->rt_gateway; 124 } 125 #ifndef notdef 126 /* 127 * If source address not specified yet, use address 128 * of outgoing interface. 129 */ 130 if (ip->ip_src.s_addr == INADDR_ANY) { 131 register struct in_ifaddr *ia; 132 133 for (ia = in_ifaddr; ia; ia = ia->ia_next) 134 if (ia->ia_ifp == ifp) { 135 ip->ip_src = IA_SIN(ia)->sin_addr; 136 break; 137 } 138 } 139 #endif 140 /* 141 * Look for broadcast address and 142 * and verify user is allowed to send 143 * such a packet. 144 */ 145 if (in_broadcast(dst->sin_addr)) { 146 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 147 error = EADDRNOTAVAIL; 148 goto bad; 149 } 150 if ((flags & IP_ALLOWBROADCAST) == 0) { 151 error = EACCES; 152 goto bad; 153 } 154 /* don't allow broadcast messages to be fragmented */ 155 if (ip->ip_len > ifp->if_mtu) { 156 error = EMSGSIZE; 157 goto bad; 158 } 159 } 160 161 /* 162 * If small enough for interface, can just send directly. 163 */ 164 if (ip->ip_len <= ifp->if_mtu) { 165 ip->ip_len = htons((u_short)ip->ip_len); 166 ip->ip_off = htons((u_short)ip->ip_off); 167 ip->ip_sum = 0; 168 ip->ip_sum = in_cksum(m, hlen); 169 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst); 170 goto done; 171 } 172 173 /* 174 * Too large for interface; fragment if possible. 175 * Must be able to put at least 8 bytes per fragment. 176 */ 177 if (ip->ip_off & IP_DF) { 178 error = EMSGSIZE; 179 goto bad; 180 } 181 len = (ifp->if_mtu - hlen) &~ 7; 182 if (len < 8) { 183 error = EMSGSIZE; 184 goto bad; 185 } 186 187 { 188 int mhlen, firstlen = len; 189 struct mbuf **mnext = &m->m_act; 190 191 /* 192 * Loop through length of segment after first fragment, 193 * make new header and copy data of each part and link onto chain. 194 */ 195 m0 = m; 196 mhlen = sizeof (struct ip); 197 for (off = hlen + len; off < ip->ip_len; off += len) { 198 MGET(m, M_DONTWAIT, MT_HEADER); 199 if (m == 0) { 200 error = ENOBUFS; 201 goto bad; 202 } 203 m->m_off = MMAXOFF - hlen; 204 mhip = mtod(m, struct ip *); 205 *mhip = *ip; 206 if (hlen > sizeof (struct ip)) { 207 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 208 mhip->ip_hl = mhlen >> 2; 209 } 210 m->m_len = mhlen; 211 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 212 if (ip->ip_off & IP_MF) 213 mhip->ip_off |= IP_MF; 214 if (off + len >= ip->ip_len) 215 len = ip->ip_len - off; 216 else 217 mhip->ip_off |= IP_MF; 218 mhip->ip_len = htons((u_short)(len + mhlen)); 219 m->m_next = m_copy(m0, off, len); 220 if (m->m_next == 0) { 221 error = ENOBUFS; /* ??? */ 222 goto sendorfree; 223 } 224 mhip->ip_off = htons((u_short)mhip->ip_off); 225 mhip->ip_sum = 0; 226 mhip->ip_sum = in_cksum(m, mhlen); 227 *mnext = m; 228 mnext = &m->m_act; 229 } 230 /* 231 * Update first fragment by trimming what's been copied out 232 * and updating header, then send each fragment (in order). 233 */ 234 m_adj(m0, hlen + firstlen - ip->ip_len); 235 ip->ip_len = htons((u_short)(hlen + firstlen)); 236 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 237 ip->ip_sum = 0; 238 ip->ip_sum = in_cksum(m0, hlen); 239 sendorfree: 240 for (m = m0; m; m = m0) { 241 m0 = m->m_act; 242 m->m_act = 0; 243 if (error == 0) 244 error = (*ifp->if_output)(ifp, m, 245 (struct sockaddr *)dst); 246 else 247 m_freem(m); 248 } 249 } 250 done: 251 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 252 RTFREE(ro->ro_rt); 253 return (error); 254 bad: 255 m_freem(m0); 256 goto done; 257 } 258 259 /* 260 * Insert IP options into preformed packet. 261 * Adjust IP destination as required for IP source routing, 262 * as indicated by a non-zero in_addr at the start of the options. 263 */ 264 struct mbuf * 265 ip_insertoptions(m, opt, phlen) 266 register struct mbuf *m; 267 struct mbuf *opt; 268 int *phlen; 269 { 270 register struct ipoption *p = mtod(opt, struct ipoption *); 271 struct mbuf *n; 272 register struct ip *ip = mtod(m, struct ip *); 273 unsigned optlen; 274 275 optlen = opt->m_len - sizeof(p->ipopt_dst); 276 if (p->ipopt_dst.s_addr) 277 ip->ip_dst = p->ipopt_dst; 278 if (m->m_off >= MMAXOFF || MMINOFF + optlen > m->m_off) { 279 MGET(n, M_DONTWAIT, MT_HEADER); 280 if (n == 0) 281 return (m); 282 m->m_len -= sizeof(struct ip); 283 m->m_off += sizeof(struct ip); 284 n->m_next = m; 285 m = n; 286 m->m_off = MMAXOFF - sizeof(struct ip) - optlen; 287 m->m_len = optlen + sizeof(struct ip); 288 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 289 } else { 290 m->m_off -= optlen; 291 m->m_len += optlen; 292 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 293 } 294 ip = mtod(m, struct ip *); 295 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 296 *phlen = sizeof(struct ip) + optlen; 297 ip->ip_len += optlen; 298 return (m); 299 } 300 301 /* 302 * Copy options from ip to jp, 303 * omitting those not copied during fragmentation. 304 */ 305 ip_optcopy(ip, jp) 306 struct ip *ip, *jp; 307 { 308 register u_char *cp, *dp; 309 int opt, optlen, cnt; 310 311 cp = (u_char *)(ip + 1); 312 dp = (u_char *)(jp + 1); 313 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 314 for (; cnt > 0; cnt -= optlen, cp += optlen) { 315 opt = cp[0]; 316 if (opt == IPOPT_EOL) 317 break; 318 if (opt == IPOPT_NOP) 319 optlen = 1; 320 else 321 optlen = cp[IPOPT_OLEN]; 322 /* bogus lengths should have been caught by ip_dooptions */ 323 if (optlen > cnt) 324 optlen = cnt; 325 if (IPOPT_COPIED(opt)) { 326 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 327 dp += optlen; 328 } 329 } 330 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 331 *dp++ = IPOPT_EOL; 332 return (optlen); 333 } 334 335 /* 336 * IP socket option processing. 337 */ 338 ip_ctloutput(op, so, level, optname, m) 339 int op; 340 struct socket *so; 341 int level, optname; 342 struct mbuf **m; 343 { 344 int error = 0; 345 struct inpcb *inp = sotoinpcb(so); 346 347 if (level != IPPROTO_IP) 348 error = EINVAL; 349 else switch (op) { 350 351 case PRCO_SETOPT: 352 switch (optname) { 353 case IP_OPTIONS: 354 return (ip_pcbopts(&inp->inp_options, *m)); 355 356 default: 357 error = EINVAL; 358 break; 359 } 360 break; 361 362 case PRCO_GETOPT: 363 switch (optname) { 364 case IP_OPTIONS: 365 *m = m_get(M_WAIT, MT_SOOPTS); 366 if (inp->inp_options) { 367 (*m)->m_off = inp->inp_options->m_off; 368 (*m)->m_len = inp->inp_options->m_len; 369 bcopy(mtod(inp->inp_options, caddr_t), 370 mtod(*m, caddr_t), (unsigned)(*m)->m_len); 371 } else 372 (*m)->m_len = 0; 373 break; 374 default: 375 error = EINVAL; 376 break; 377 } 378 break; 379 } 380 if (op == PRCO_SETOPT && *m) 381 (void)m_free(*m); 382 return (error); 383 } 384 385 /* 386 * Set up IP options in pcb for insertion in output packets. 387 * Store in mbuf with pointer in pcbopt, adding pseudo-option 388 * with destination address if source routed. 389 */ 390 ip_pcbopts(pcbopt, m) 391 struct mbuf **pcbopt; 392 register struct mbuf *m; 393 { 394 register cnt, optlen; 395 register u_char *cp; 396 u_char opt; 397 398 /* turn off any old options */ 399 if (*pcbopt) 400 (void)m_free(*pcbopt); 401 *pcbopt = 0; 402 if (m == (struct mbuf *)0 || m->m_len == 0) { 403 /* 404 * Only turning off any previous options. 405 */ 406 if (m) 407 (void)m_free(m); 408 return (0); 409 } 410 411 #ifndef vax 412 if (m->m_len % sizeof(long)) 413 goto bad; 414 #endif 415 /* 416 * IP first-hop destination address will be stored before 417 * actual options; move other options back 418 * and clear it when none present. 419 */ 420 #if MAX_IPOPTLEN >= MMAXOFF - MMINOFF 421 if (m->m_off + m->m_len + sizeof(struct in_addr) > MAX_IPOPTLEN) 422 goto bad; 423 #else 424 if (m->m_off + m->m_len + sizeof(struct in_addr) > MMAXOFF) 425 goto bad; 426 #endif 427 cnt = m->m_len; 428 m->m_len += sizeof(struct in_addr); 429 cp = mtod(m, u_char *) + sizeof(struct in_addr); 430 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 431 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 432 433 for (; cnt > 0; cnt -= optlen, cp += optlen) { 434 opt = cp[IPOPT_OPTVAL]; 435 if (opt == IPOPT_EOL) 436 break; 437 if (opt == IPOPT_NOP) 438 optlen = 1; 439 else { 440 optlen = cp[IPOPT_OLEN]; 441 if (optlen <= IPOPT_OLEN || optlen > cnt) 442 goto bad; 443 } 444 switch (opt) { 445 446 default: 447 break; 448 449 case IPOPT_LSRR: 450 case IPOPT_SSRR: 451 /* 452 * user process specifies route as: 453 * ->A->B->C->D 454 * D must be our final destination (but we can't 455 * check that since we may not have connected yet). 456 * A is first hop destination, which doesn't appear in 457 * actual IP option, but is stored before the options. 458 */ 459 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 460 goto bad; 461 m->m_len -= sizeof(struct in_addr); 462 cnt -= sizeof(struct in_addr); 463 optlen -= sizeof(struct in_addr); 464 cp[IPOPT_OLEN] = optlen; 465 /* 466 * Move first hop before start of options. 467 */ 468 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 469 sizeof(struct in_addr)); 470 /* 471 * Then copy rest of options back 472 * to close up the deleted entry. 473 */ 474 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 475 sizeof(struct in_addr)), 476 (caddr_t)&cp[IPOPT_OFFSET+1], 477 (unsigned)cnt + sizeof(struct in_addr)); 478 break; 479 } 480 } 481 *pcbopt = m; 482 return (0); 483 484 bad: 485 (void)m_free(m); 486 return (EINVAL); 487 } 488