1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993 3 * The Regents of the University of California. 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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_ipfw.h" 36 #include "opt_ipsec.h" 37 #include "opt_mac.h" 38 #include "opt_mbuf_stress_test.h" 39 #include "opt_mpath.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/malloc.h> 45 #include <sys/mbuf.h> 46 #include <sys/priv.h> 47 #include <sys/proc.h> 48 #include <sys/protosw.h> 49 #include <sys/socket.h> 50 #include <sys/socketvar.h> 51 #include <sys/sysctl.h> 52 #include <sys/ucred.h> 53 #include <sys/vimage.h> 54 55 #include <net/if.h> 56 #include <net/netisr.h> 57 #include <net/pfil.h> 58 #include <net/route.h> 59 #ifdef RADIX_MPATH 60 #include <net/radix_mpath.h> 61 #endif 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/ip.h> 66 #include <netinet/in_pcb.h> 67 #include <netinet/in_var.h> 68 #include <netinet/ip_var.h> 69 #include <netinet/ip_options.h> 70 71 #ifdef IPSEC 72 #include <netinet/ip_ipsec.h> 73 #include <netipsec/ipsec.h> 74 #endif /* IPSEC*/ 75 76 #include <machine/in_cksum.h> 77 78 #include <security/mac/mac_framework.h> 79 80 #define print_ip(x, a, y) printf("%s %d.%d.%d.%d%s",\ 81 x, (ntohl(a.s_addr)>>24)&0xFF,\ 82 (ntohl(a.s_addr)>>16)&0xFF,\ 83 (ntohl(a.s_addr)>>8)&0xFF,\ 84 (ntohl(a.s_addr))&0xFF, y); 85 86 u_short ip_id; 87 88 #ifdef MBUF_STRESS_TEST 89 int mbuf_frag_size = 0; 90 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 91 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 92 #endif 93 94 static void ip_mloopback 95 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 96 97 98 extern struct protosw inetsw[]; 99 100 /* 101 * IP output. The packet in mbuf chain m contains a skeletal IP 102 * header (with len, off, ttl, proto, tos, src, dst). 103 * The mbuf chain containing the packet will be freed. 104 * The mbuf opt, if present, will not be freed. 105 * In the IP forwarding case, the packet will arrive with options already 106 * inserted, so must have a NULL opt pointer. 107 */ 108 int 109 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 110 struct ip_moptions *imo, struct inpcb *inp) 111 { 112 INIT_VNET_NET(curvnet); 113 INIT_VNET_INET(curvnet); 114 struct ip *ip; 115 struct ifnet *ifp = NULL; /* keep compiler happy */ 116 struct mbuf *m0; 117 int hlen = sizeof (struct ip); 118 int mtu; 119 int len, error = 0; 120 struct sockaddr_in *dst = NULL; /* keep compiler happy */ 121 struct in_ifaddr *ia = NULL; 122 int isbroadcast, sw_csum; 123 struct route iproute; 124 struct in_addr odst; 125 #ifdef IPFIREWALL_FORWARD 126 struct m_tag *fwd_tag = NULL; 127 #endif 128 M_ASSERTPKTHDR(m); 129 130 if (ro == NULL) { 131 ro = &iproute; 132 bzero(ro, sizeof (*ro)); 133 } 134 135 if (inp != NULL) 136 INP_LOCK_ASSERT(inp); 137 138 if (opt) { 139 len = 0; 140 m = ip_insertoptions(m, opt, &len); 141 if (len != 0) 142 hlen = len; 143 } 144 ip = mtod(m, struct ip *); 145 146 /* 147 * Fill in IP header. If we are not allowing fragmentation, 148 * then the ip_id field is meaningless, but we don't set it 149 * to zero. Doing so causes various problems when devices along 150 * the path (routers, load balancers, firewalls, etc.) illegally 151 * disable DF on our packet. Note that a 16-bit counter 152 * will wrap around in less than 10 seconds at 100 Mbit/s on a 153 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 154 * for Counting NATted Hosts", Proc. IMW'02, available at 155 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 156 */ 157 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 158 ip->ip_v = IPVERSION; 159 ip->ip_hl = hlen >> 2; 160 ip->ip_id = ip_newid(); 161 V_ipstat.ips_localout++; 162 } else { 163 hlen = ip->ip_hl << 2; 164 } 165 166 dst = (struct sockaddr_in *)&ro->ro_dst; 167 again: 168 /* 169 * If there is a cached route, 170 * check that it is to the same destination 171 * and is still up. If not, free it and try again. 172 * The address family should also be checked in case of sharing the 173 * cache with IPv6. 174 */ 175 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 176 dst->sin_family != AF_INET || 177 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 178 RTFREE(ro->ro_rt); 179 ro->ro_rt = (struct rtentry *)NULL; 180 } 181 #ifdef IPFIREWALL_FORWARD 182 if (ro->ro_rt == NULL && fwd_tag == NULL) { 183 #else 184 if (ro->ro_rt == NULL) { 185 #endif 186 bzero(dst, sizeof(*dst)); 187 dst->sin_family = AF_INET; 188 dst->sin_len = sizeof(*dst); 189 dst->sin_addr = ip->ip_dst; 190 } 191 /* 192 * If routing to interface only, short circuit routing lookup. 193 * The use of an all-ones broadcast address implies this; an 194 * interface is specified by the broadcast address of an interface, 195 * or the destination address of a ptp interface. 196 */ 197 if (flags & IP_SENDONES) { 198 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 199 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 200 V_ipstat.ips_noroute++; 201 error = ENETUNREACH; 202 goto bad; 203 } 204 ip->ip_dst.s_addr = INADDR_BROADCAST; 205 dst->sin_addr = ip->ip_dst; 206 ifp = ia->ia_ifp; 207 ip->ip_ttl = 1; 208 isbroadcast = 1; 209 } else if (flags & IP_ROUTETOIF) { 210 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 211 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) { 212 V_ipstat.ips_noroute++; 213 error = ENETUNREACH; 214 goto bad; 215 } 216 ifp = ia->ia_ifp; 217 ip->ip_ttl = 1; 218 isbroadcast = in_broadcast(dst->sin_addr, ifp); 219 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 220 imo != NULL && imo->imo_multicast_ifp != NULL) { 221 /* 222 * Bypass the normal routing lookup for multicast 223 * packets if the interface is specified. 224 */ 225 ifp = imo->imo_multicast_ifp; 226 IFP_TO_IA(ifp, ia); 227 isbroadcast = 0; /* fool gcc */ 228 } else { 229 /* 230 * We want to do any cloning requested by the link layer, 231 * as this is probably required in all cases for correct 232 * operation (as it is for ARP). 233 */ 234 if (ro->ro_rt == NULL) 235 #ifdef RADIX_MPATH 236 rtalloc_mpath_fib(ro, 237 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 238 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 239 #else 240 in_rtalloc_ign(ro, 0, 241 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 242 #endif 243 if (ro->ro_rt == NULL) { 244 V_ipstat.ips_noroute++; 245 error = EHOSTUNREACH; 246 goto bad; 247 } 248 ia = ifatoia(ro->ro_rt->rt_ifa); 249 ifp = ro->ro_rt->rt_ifp; 250 ro->ro_rt->rt_rmx.rmx_pksent++; 251 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 252 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 253 if (ro->ro_rt->rt_flags & RTF_HOST) 254 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST); 255 else 256 isbroadcast = in_broadcast(dst->sin_addr, ifp); 257 } 258 /* 259 * Calculate MTU. If we have a route that is up, use that, 260 * otherwise use the interface's MTU. 261 */ 262 if (ro->ro_rt != NULL && (ro->ro_rt->rt_flags & (RTF_UP|RTF_HOST))) { 263 /* 264 * This case can happen if the user changed the MTU 265 * of an interface after enabling IP on it. Because 266 * most netifs don't keep track of routes pointing to 267 * them, there is no way for one to update all its 268 * routes when the MTU is changed. 269 */ 270 if (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu) 271 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu; 272 mtu = ro->ro_rt->rt_rmx.rmx_mtu; 273 } else { 274 mtu = ifp->if_mtu; 275 } 276 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 277 struct in_multi *inm; 278 279 m->m_flags |= M_MCAST; 280 /* 281 * IP destination address is multicast. Make sure "dst" 282 * still points to the address in "ro". (It may have been 283 * changed to point to a gateway address, above.) 284 */ 285 dst = (struct sockaddr_in *)&ro->ro_dst; 286 /* 287 * See if the caller provided any multicast options 288 */ 289 if (imo != NULL) { 290 ip->ip_ttl = imo->imo_multicast_ttl; 291 if (imo->imo_multicast_vif != -1) 292 ip->ip_src.s_addr = 293 ip_mcast_src ? 294 ip_mcast_src(imo->imo_multicast_vif) : 295 INADDR_ANY; 296 } else 297 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 298 /* 299 * Confirm that the outgoing interface supports multicast. 300 */ 301 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 302 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 303 V_ipstat.ips_noroute++; 304 error = ENETUNREACH; 305 goto bad; 306 } 307 } 308 /* 309 * If source address not specified yet, use address 310 * of outgoing interface. 311 */ 312 if (ip->ip_src.s_addr == INADDR_ANY) { 313 /* Interface may have no addresses. */ 314 if (ia != NULL) 315 ip->ip_src = IA_SIN(ia)->sin_addr; 316 } 317 318 IN_MULTI_LOCK(); 319 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 320 if (inm != NULL && 321 (imo == NULL || imo->imo_multicast_loop)) { 322 IN_MULTI_UNLOCK(); 323 /* 324 * If we belong to the destination multicast group 325 * on the outgoing interface, and the caller did not 326 * forbid loopback, loop back a copy. 327 */ 328 ip_mloopback(ifp, m, dst, hlen); 329 } 330 else { 331 IN_MULTI_UNLOCK(); 332 /* 333 * If we are acting as a multicast router, perform 334 * multicast forwarding as if the packet had just 335 * arrived on the interface to which we are about 336 * to send. The multicast forwarding function 337 * recursively calls this function, using the 338 * IP_FORWARDING flag to prevent infinite recursion. 339 * 340 * Multicasts that are looped back by ip_mloopback(), 341 * above, will be forwarded by the ip_input() routine, 342 * if necessary. 343 */ 344 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) { 345 /* 346 * If rsvp daemon is not running, do not 347 * set ip_moptions. This ensures that the packet 348 * is multicast and not just sent down one link 349 * as prescribed by rsvpd. 350 */ 351 if (!V_rsvp_on) 352 imo = NULL; 353 if (ip_mforward && 354 ip_mforward(ip, ifp, m, imo) != 0) { 355 m_freem(m); 356 goto done; 357 } 358 } 359 } 360 361 /* 362 * Multicasts with a time-to-live of zero may be looped- 363 * back, above, but must not be transmitted on a network. 364 * Also, multicasts addressed to the loopback interface 365 * are not sent -- the above call to ip_mloopback() will 366 * loop back a copy if this host actually belongs to the 367 * destination group on the loopback interface. 368 */ 369 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 370 m_freem(m); 371 goto done; 372 } 373 374 goto sendit; 375 } 376 377 /* 378 * If the source address is not specified yet, use the address 379 * of the outoing interface. 380 */ 381 if (ip->ip_src.s_addr == INADDR_ANY) { 382 /* Interface may have no addresses. */ 383 if (ia != NULL) { 384 ip->ip_src = IA_SIN(ia)->sin_addr; 385 } 386 } 387 388 /* 389 * Verify that we have any chance at all of being able to queue the 390 * packet or packet fragments, unless ALTQ is enabled on the given 391 * interface in which case packetdrop should be done by queueing. 392 */ 393 #ifdef ALTQ 394 if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) && 395 ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 396 ifp->if_snd.ifq_maxlen)) 397 #else 398 if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 399 ifp->if_snd.ifq_maxlen) 400 #endif /* ALTQ */ 401 { 402 error = ENOBUFS; 403 V_ipstat.ips_odropped++; 404 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1); 405 goto bad; 406 } 407 408 /* 409 * Look for broadcast address and 410 * verify user is allowed to send 411 * such a packet. 412 */ 413 if (isbroadcast) { 414 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 415 error = EADDRNOTAVAIL; 416 goto bad; 417 } 418 if ((flags & IP_ALLOWBROADCAST) == 0) { 419 error = EACCES; 420 goto bad; 421 } 422 /* don't allow broadcast messages to be fragmented */ 423 if (ip->ip_len > mtu) { 424 error = EMSGSIZE; 425 goto bad; 426 } 427 m->m_flags |= M_BCAST; 428 } else { 429 m->m_flags &= ~M_BCAST; 430 } 431 432 sendit: 433 #ifdef IPSEC 434 switch(ip_ipsec_output(&m, inp, &flags, &error, &ro, &iproute, &dst, &ia, &ifp)) { 435 case 1: 436 goto bad; 437 case -1: 438 goto done; 439 case 0: 440 default: 441 break; /* Continue with packet processing. */ 442 } 443 /* Update variables that are affected by ipsec4_output(). */ 444 ip = mtod(m, struct ip *); 445 hlen = ip->ip_hl << 2; 446 #endif /* IPSEC */ 447 448 /* Jump over all PFIL processing if hooks are not active. */ 449 if (!PFIL_HOOKED(&inet_pfil_hook)) 450 goto passout; 451 452 /* Run through list of hooks for output packets. */ 453 odst.s_addr = ip->ip_dst.s_addr; 454 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 455 if (error != 0 || m == NULL) 456 goto done; 457 458 ip = mtod(m, struct ip *); 459 460 /* See if destination IP address was changed by packet filter. */ 461 if (odst.s_addr != ip->ip_dst.s_addr) { 462 m->m_flags |= M_SKIP_FIREWALL; 463 /* If destination is now ourself drop to ip_input(). */ 464 if (in_localip(ip->ip_dst)) { 465 m->m_flags |= M_FASTFWD_OURS; 466 if (m->m_pkthdr.rcvif == NULL) 467 m->m_pkthdr.rcvif = V_loif; 468 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 469 m->m_pkthdr.csum_flags |= 470 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 471 m->m_pkthdr.csum_data = 0xffff; 472 } 473 m->m_pkthdr.csum_flags |= 474 CSUM_IP_CHECKED | CSUM_IP_VALID; 475 476 error = netisr_queue(NETISR_IP, m); 477 goto done; 478 } else 479 goto again; /* Redo the routing table lookup. */ 480 } 481 482 #ifdef IPFIREWALL_FORWARD 483 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 484 if (m->m_flags & M_FASTFWD_OURS) { 485 if (m->m_pkthdr.rcvif == NULL) 486 m->m_pkthdr.rcvif = V_loif; 487 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 488 m->m_pkthdr.csum_flags |= 489 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 490 m->m_pkthdr.csum_data = 0xffff; 491 } 492 m->m_pkthdr.csum_flags |= 493 CSUM_IP_CHECKED | CSUM_IP_VALID; 494 495 error = netisr_queue(NETISR_IP, m); 496 goto done; 497 } 498 /* Or forward to some other address? */ 499 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 500 if (fwd_tag) { 501 dst = (struct sockaddr_in *)&ro->ro_dst; 502 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 503 m->m_flags |= M_SKIP_FIREWALL; 504 m_tag_delete(m, fwd_tag); 505 goto again; 506 } 507 #endif /* IPFIREWALL_FORWARD */ 508 509 passout: 510 /* 127/8 must not appear on wire - RFC1122. */ 511 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 512 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 513 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 514 V_ipstat.ips_badaddr++; 515 error = EADDRNOTAVAIL; 516 goto bad; 517 } 518 } 519 520 m->m_pkthdr.csum_flags |= CSUM_IP; 521 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 522 if (sw_csum & CSUM_DELAY_DATA) { 523 in_delayed_cksum(m); 524 sw_csum &= ~CSUM_DELAY_DATA; 525 } 526 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 527 528 /* 529 * If small enough for interface, or the interface will take 530 * care of the fragmentation for us, we can just send directly. 531 */ 532 if (ip->ip_len <= mtu || 533 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 534 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 535 ip->ip_len = htons(ip->ip_len); 536 ip->ip_off = htons(ip->ip_off); 537 ip->ip_sum = 0; 538 if (sw_csum & CSUM_DELAY_IP) 539 ip->ip_sum = in_cksum(m, hlen); 540 541 /* 542 * Record statistics for this interface address. 543 * With CSUM_TSO the byte/packet count will be slightly 544 * incorrect because we count the IP+TCP headers only 545 * once instead of for every generated packet. 546 */ 547 if (!(flags & IP_FORWARDING) && ia) { 548 if (m->m_pkthdr.csum_flags & CSUM_TSO) 549 ia->ia_ifa.if_opackets += 550 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 551 else 552 ia->ia_ifa.if_opackets++; 553 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 554 } 555 #ifdef MBUF_STRESS_TEST 556 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 557 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 558 #endif 559 /* 560 * Reset layer specific mbuf flags 561 * to avoid confusing lower layers. 562 */ 563 m->m_flags &= ~(M_PROTOFLAGS); 564 565 error = (*ifp->if_output)(ifp, m, 566 (struct sockaddr *)dst, ro->ro_rt); 567 goto done; 568 } 569 570 /* Balk when DF bit is set or the interface didn't support TSO. */ 571 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 572 error = EMSGSIZE; 573 V_ipstat.ips_cantfrag++; 574 goto bad; 575 } 576 577 /* 578 * Too large for interface; fragment if possible. If successful, 579 * on return, m will point to a list of packets to be sent. 580 */ 581 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 582 if (error) 583 goto bad; 584 for (; m; m = m0) { 585 m0 = m->m_nextpkt; 586 m->m_nextpkt = 0; 587 if (error == 0) { 588 /* Record statistics for this interface address. */ 589 if (ia != NULL) { 590 ia->ia_ifa.if_opackets++; 591 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 592 } 593 /* 594 * Reset layer specific mbuf flags 595 * to avoid confusing upper layers. 596 */ 597 m->m_flags &= ~(M_PROTOFLAGS); 598 599 error = (*ifp->if_output)(ifp, m, 600 (struct sockaddr *)dst, ro->ro_rt); 601 } else 602 m_freem(m); 603 } 604 605 if (error == 0) 606 V_ipstat.ips_fragmented++; 607 608 done: 609 if (ro == &iproute && ro->ro_rt) { 610 RTFREE(ro->ro_rt); 611 } 612 return (error); 613 bad: 614 m_freem(m); 615 goto done; 616 } 617 618 /* 619 * Create a chain of fragments which fit the given mtu. m_frag points to the 620 * mbuf to be fragmented; on return it points to the chain with the fragments. 621 * Return 0 if no error. If error, m_frag may contain a partially built 622 * chain of fragments that should be freed by the caller. 623 * 624 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 625 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 626 */ 627 int 628 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 629 u_long if_hwassist_flags, int sw_csum) 630 { 631 INIT_VNET_INET(curvnet); 632 int error = 0; 633 int hlen = ip->ip_hl << 2; 634 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 635 int off; 636 struct mbuf *m0 = *m_frag; /* the original packet */ 637 int firstlen; 638 struct mbuf **mnext; 639 int nfrags; 640 641 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */ 642 V_ipstat.ips_cantfrag++; 643 return EMSGSIZE; 644 } 645 646 /* 647 * Must be able to put at least 8 bytes per fragment. 648 */ 649 if (len < 8) 650 return EMSGSIZE; 651 652 /* 653 * If the interface will not calculate checksums on 654 * fragmented packets, then do it here. 655 */ 656 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 657 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 658 in_delayed_cksum(m0); 659 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 660 } 661 662 if (len > PAGE_SIZE) { 663 /* 664 * Fragment large datagrams such that each segment 665 * contains a multiple of PAGE_SIZE amount of data, 666 * plus headers. This enables a receiver to perform 667 * page-flipping zero-copy optimizations. 668 * 669 * XXX When does this help given that sender and receiver 670 * could have different page sizes, and also mtu could 671 * be less than the receiver's page size ? 672 */ 673 int newlen; 674 struct mbuf *m; 675 676 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 677 off += m->m_len; 678 679 /* 680 * firstlen (off - hlen) must be aligned on an 681 * 8-byte boundary 682 */ 683 if (off < hlen) 684 goto smart_frag_failure; 685 off = ((off - hlen) & ~7) + hlen; 686 newlen = (~PAGE_MASK) & mtu; 687 if ((newlen + sizeof (struct ip)) > mtu) { 688 /* we failed, go back the default */ 689 smart_frag_failure: 690 newlen = len; 691 off = hlen + len; 692 } 693 len = newlen; 694 695 } else { 696 off = hlen + len; 697 } 698 699 firstlen = off - hlen; 700 mnext = &m0->m_nextpkt; /* pointer to next packet */ 701 702 /* 703 * Loop through length of segment after first fragment, 704 * make new header and copy data of each part and link onto chain. 705 * Here, m0 is the original packet, m is the fragment being created. 706 * The fragments are linked off the m_nextpkt of the original 707 * packet, which after processing serves as the first fragment. 708 */ 709 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) { 710 struct ip *mhip; /* ip header on the fragment */ 711 struct mbuf *m; 712 int mhlen = sizeof (struct ip); 713 714 MGETHDR(m, M_DONTWAIT, MT_DATA); 715 if (m == NULL) { 716 error = ENOBUFS; 717 V_ipstat.ips_odropped++; 718 goto done; 719 } 720 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 721 /* 722 * In the first mbuf, leave room for the link header, then 723 * copy the original IP header including options. The payload 724 * goes into an additional mbuf chain returned by m_copy(). 725 */ 726 m->m_data += max_linkhdr; 727 mhip = mtod(m, struct ip *); 728 *mhip = *ip; 729 if (hlen > sizeof (struct ip)) { 730 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 731 mhip->ip_v = IPVERSION; 732 mhip->ip_hl = mhlen >> 2; 733 } 734 m->m_len = mhlen; 735 /* XXX do we need to add ip->ip_off below ? */ 736 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off; 737 if (off + len >= ip->ip_len) { /* last fragment */ 738 len = ip->ip_len - off; 739 m->m_flags |= M_LASTFRAG; 740 } else 741 mhip->ip_off |= IP_MF; 742 mhip->ip_len = htons((u_short)(len + mhlen)); 743 m->m_next = m_copy(m0, off, len); 744 if (m->m_next == NULL) { /* copy failed */ 745 m_free(m); 746 error = ENOBUFS; /* ??? */ 747 V_ipstat.ips_odropped++; 748 goto done; 749 } 750 m->m_pkthdr.len = mhlen + len; 751 m->m_pkthdr.rcvif = NULL; 752 #ifdef MAC 753 mac_netinet_fragment(m0, m); 754 #endif 755 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 756 mhip->ip_off = htons(mhip->ip_off); 757 mhip->ip_sum = 0; 758 if (sw_csum & CSUM_DELAY_IP) 759 mhip->ip_sum = in_cksum(m, mhlen); 760 *mnext = m; 761 mnext = &m->m_nextpkt; 762 } 763 V_ipstat.ips_ofragments += nfrags; 764 765 /* set first marker for fragment chain */ 766 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 767 m0->m_pkthdr.csum_data = nfrags; 768 769 /* 770 * Update first fragment by trimming what's been copied out 771 * and updating header. 772 */ 773 m_adj(m0, hlen + firstlen - ip->ip_len); 774 m0->m_pkthdr.len = hlen + firstlen; 775 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 776 ip->ip_off |= IP_MF; 777 ip->ip_off = htons(ip->ip_off); 778 ip->ip_sum = 0; 779 if (sw_csum & CSUM_DELAY_IP) 780 ip->ip_sum = in_cksum(m0, hlen); 781 782 done: 783 *m_frag = m0; 784 return error; 785 } 786 787 void 788 in_delayed_cksum(struct mbuf *m) 789 { 790 struct ip *ip; 791 u_short csum, offset; 792 793 ip = mtod(m, struct ip *); 794 offset = ip->ip_hl << 2 ; 795 csum = in_cksum_skip(m, ip->ip_len, offset); 796 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 797 csum = 0xffff; 798 offset += m->m_pkthdr.csum_data; /* checksum offset */ 799 800 if (offset + sizeof(u_short) > m->m_len) { 801 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 802 m->m_len, offset, ip->ip_p); 803 /* 804 * XXX 805 * this shouldn't happen, but if it does, the 806 * correct behavior may be to insert the checksum 807 * in the appropriate next mbuf in the chain. 808 */ 809 return; 810 } 811 *(u_short *)(m->m_data + offset) = csum; 812 } 813 814 /* 815 * IP socket option processing. 816 */ 817 int 818 ip_ctloutput(struct socket *so, struct sockopt *sopt) 819 { 820 struct inpcb *inp = sotoinpcb(so); 821 int error, optval; 822 823 error = optval = 0; 824 if (sopt->sopt_level != IPPROTO_IP) { 825 return (EINVAL); 826 } 827 828 switch (sopt->sopt_dir) { 829 case SOPT_SET: 830 switch (sopt->sopt_name) { 831 case IP_OPTIONS: 832 #ifdef notyet 833 case IP_RETOPTS: 834 #endif 835 { 836 struct mbuf *m; 837 if (sopt->sopt_valsize > MLEN) { 838 error = EMSGSIZE; 839 break; 840 } 841 MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, MT_DATA); 842 if (m == NULL) { 843 error = ENOBUFS; 844 break; 845 } 846 m->m_len = sopt->sopt_valsize; 847 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 848 m->m_len); 849 if (error) { 850 m_free(m); 851 break; 852 } 853 INP_WLOCK(inp); 854 error = ip_pcbopts(inp, sopt->sopt_name, m); 855 INP_WUNLOCK(inp); 856 return (error); 857 } 858 859 case IP_TOS: 860 case IP_TTL: 861 case IP_MINTTL: 862 case IP_RECVOPTS: 863 case IP_RECVRETOPTS: 864 case IP_RECVDSTADDR: 865 case IP_RECVTTL: 866 case IP_RECVIF: 867 case IP_FAITH: 868 case IP_ONESBCAST: 869 case IP_DONTFRAG: 870 error = sooptcopyin(sopt, &optval, sizeof optval, 871 sizeof optval); 872 if (error) 873 break; 874 875 switch (sopt->sopt_name) { 876 case IP_TOS: 877 inp->inp_ip_tos = optval; 878 break; 879 880 case IP_TTL: 881 inp->inp_ip_ttl = optval; 882 break; 883 884 case IP_MINTTL: 885 if (optval > 0 && optval <= MAXTTL) 886 inp->inp_ip_minttl = optval; 887 else 888 error = EINVAL; 889 break; 890 891 #define OPTSET(bit) do { \ 892 INP_WLOCK(inp); \ 893 if (optval) \ 894 inp->inp_flags |= bit; \ 895 else \ 896 inp->inp_flags &= ~bit; \ 897 INP_WUNLOCK(inp); \ 898 } while (0) 899 900 case IP_RECVOPTS: 901 OPTSET(INP_RECVOPTS); 902 break; 903 904 case IP_RECVRETOPTS: 905 OPTSET(INP_RECVRETOPTS); 906 break; 907 908 case IP_RECVDSTADDR: 909 OPTSET(INP_RECVDSTADDR); 910 break; 911 912 case IP_RECVTTL: 913 OPTSET(INP_RECVTTL); 914 break; 915 916 case IP_RECVIF: 917 OPTSET(INP_RECVIF); 918 break; 919 920 case IP_FAITH: 921 OPTSET(INP_FAITH); 922 break; 923 924 case IP_ONESBCAST: 925 OPTSET(INP_ONESBCAST); 926 break; 927 case IP_DONTFRAG: 928 OPTSET(INP_DONTFRAG); 929 break; 930 } 931 break; 932 #undef OPTSET 933 934 /* 935 * Multicast socket options are processed by the in_mcast 936 * module. 937 */ 938 case IP_MULTICAST_IF: 939 case IP_MULTICAST_VIF: 940 case IP_MULTICAST_TTL: 941 case IP_MULTICAST_LOOP: 942 case IP_ADD_MEMBERSHIP: 943 case IP_DROP_MEMBERSHIP: 944 case IP_ADD_SOURCE_MEMBERSHIP: 945 case IP_DROP_SOURCE_MEMBERSHIP: 946 case IP_BLOCK_SOURCE: 947 case IP_UNBLOCK_SOURCE: 948 case IP_MSFILTER: 949 case MCAST_JOIN_GROUP: 950 case MCAST_LEAVE_GROUP: 951 case MCAST_JOIN_SOURCE_GROUP: 952 case MCAST_LEAVE_SOURCE_GROUP: 953 case MCAST_BLOCK_SOURCE: 954 case MCAST_UNBLOCK_SOURCE: 955 error = inp_setmoptions(inp, sopt); 956 break; 957 958 case IP_PORTRANGE: 959 error = sooptcopyin(sopt, &optval, sizeof optval, 960 sizeof optval); 961 if (error) 962 break; 963 964 INP_WLOCK(inp); 965 switch (optval) { 966 case IP_PORTRANGE_DEFAULT: 967 inp->inp_flags &= ~(INP_LOWPORT); 968 inp->inp_flags &= ~(INP_HIGHPORT); 969 break; 970 971 case IP_PORTRANGE_HIGH: 972 inp->inp_flags &= ~(INP_LOWPORT); 973 inp->inp_flags |= INP_HIGHPORT; 974 break; 975 976 case IP_PORTRANGE_LOW: 977 inp->inp_flags &= ~(INP_HIGHPORT); 978 inp->inp_flags |= INP_LOWPORT; 979 break; 980 981 default: 982 error = EINVAL; 983 break; 984 } 985 INP_WUNLOCK(inp); 986 break; 987 988 #ifdef IPSEC 989 case IP_IPSEC_POLICY: 990 { 991 caddr_t req; 992 struct mbuf *m; 993 994 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 995 break; 996 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 997 break; 998 req = mtod(m, caddr_t); 999 error = ipsec4_set_policy(inp, sopt->sopt_name, req, 1000 m->m_len, (sopt->sopt_td != NULL) ? 1001 sopt->sopt_td->td_ucred : NULL); 1002 m_freem(m); 1003 break; 1004 } 1005 #endif /* IPSEC */ 1006 1007 default: 1008 error = ENOPROTOOPT; 1009 break; 1010 } 1011 break; 1012 1013 case SOPT_GET: 1014 switch (sopt->sopt_name) { 1015 case IP_OPTIONS: 1016 case IP_RETOPTS: 1017 if (inp->inp_options) 1018 error = sooptcopyout(sopt, 1019 mtod(inp->inp_options, 1020 char *), 1021 inp->inp_options->m_len); 1022 else 1023 sopt->sopt_valsize = 0; 1024 break; 1025 1026 case IP_TOS: 1027 case IP_TTL: 1028 case IP_MINTTL: 1029 case IP_RECVOPTS: 1030 case IP_RECVRETOPTS: 1031 case IP_RECVDSTADDR: 1032 case IP_RECVTTL: 1033 case IP_RECVIF: 1034 case IP_PORTRANGE: 1035 case IP_FAITH: 1036 case IP_ONESBCAST: 1037 case IP_DONTFRAG: 1038 switch (sopt->sopt_name) { 1039 1040 case IP_TOS: 1041 optval = inp->inp_ip_tos; 1042 break; 1043 1044 case IP_TTL: 1045 optval = inp->inp_ip_ttl; 1046 break; 1047 1048 case IP_MINTTL: 1049 optval = inp->inp_ip_minttl; 1050 break; 1051 1052 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1053 1054 case IP_RECVOPTS: 1055 optval = OPTBIT(INP_RECVOPTS); 1056 break; 1057 1058 case IP_RECVRETOPTS: 1059 optval = OPTBIT(INP_RECVRETOPTS); 1060 break; 1061 1062 case IP_RECVDSTADDR: 1063 optval = OPTBIT(INP_RECVDSTADDR); 1064 break; 1065 1066 case IP_RECVTTL: 1067 optval = OPTBIT(INP_RECVTTL); 1068 break; 1069 1070 case IP_RECVIF: 1071 optval = OPTBIT(INP_RECVIF); 1072 break; 1073 1074 case IP_PORTRANGE: 1075 if (inp->inp_flags & INP_HIGHPORT) 1076 optval = IP_PORTRANGE_HIGH; 1077 else if (inp->inp_flags & INP_LOWPORT) 1078 optval = IP_PORTRANGE_LOW; 1079 else 1080 optval = 0; 1081 break; 1082 1083 case IP_FAITH: 1084 optval = OPTBIT(INP_FAITH); 1085 break; 1086 1087 case IP_ONESBCAST: 1088 optval = OPTBIT(INP_ONESBCAST); 1089 break; 1090 case IP_DONTFRAG: 1091 optval = OPTBIT(INP_DONTFRAG); 1092 break; 1093 } 1094 error = sooptcopyout(sopt, &optval, sizeof optval); 1095 break; 1096 1097 /* 1098 * Multicast socket options are processed by the in_mcast 1099 * module. 1100 */ 1101 case IP_MULTICAST_IF: 1102 case IP_MULTICAST_VIF: 1103 case IP_MULTICAST_TTL: 1104 case IP_MULTICAST_LOOP: 1105 case IP_MSFILTER: 1106 error = inp_getmoptions(inp, sopt); 1107 break; 1108 1109 #ifdef IPSEC 1110 case IP_IPSEC_POLICY: 1111 { 1112 struct mbuf *m = NULL; 1113 caddr_t req = NULL; 1114 size_t len = 0; 1115 1116 if (m != 0) { 1117 req = mtod(m, caddr_t); 1118 len = m->m_len; 1119 } 1120 error = ipsec4_get_policy(sotoinpcb(so), req, len, &m); 1121 if (error == 0) 1122 error = soopt_mcopyout(sopt, m); /* XXX */ 1123 if (error == 0) 1124 m_freem(m); 1125 break; 1126 } 1127 #endif /* IPSEC */ 1128 1129 default: 1130 error = ENOPROTOOPT; 1131 break; 1132 } 1133 break; 1134 } 1135 return (error); 1136 } 1137 1138 /* 1139 * Routine called from ip_output() to loop back a copy of an IP multicast 1140 * packet to the input queue of a specified interface. Note that this 1141 * calls the output routine of the loopback "driver", but with an interface 1142 * pointer that might NOT be a loopback interface -- evil, but easier than 1143 * replicating that code here. 1144 */ 1145 static void 1146 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1147 int hlen) 1148 { 1149 register struct ip *ip; 1150 struct mbuf *copym; 1151 1152 /* 1153 * Make a deep copy of the packet because we're going to 1154 * modify the pack in order to generate checksums. 1155 */ 1156 copym = m_dup(m, M_DONTWAIT); 1157 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1158 copym = m_pullup(copym, hlen); 1159 if (copym != NULL) { 1160 /* If needed, compute the checksum and mark it as valid. */ 1161 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1162 in_delayed_cksum(copym); 1163 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1164 copym->m_pkthdr.csum_flags |= 1165 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1166 copym->m_pkthdr.csum_data = 0xffff; 1167 } 1168 /* 1169 * We don't bother to fragment if the IP length is greater 1170 * than the interface's MTU. Can this possibly matter? 1171 */ 1172 ip = mtod(copym, struct ip *); 1173 ip->ip_len = htons(ip->ip_len); 1174 ip->ip_off = htons(ip->ip_off); 1175 ip->ip_sum = 0; 1176 ip->ip_sum = in_cksum(copym, hlen); 1177 #if 1 /* XXX */ 1178 if (dst->sin_family != AF_INET) { 1179 printf("ip_mloopback: bad address family %d\n", 1180 dst->sin_family); 1181 dst->sin_family = AF_INET; 1182 } 1183 #endif 1184 if_simloop(ifp, copym, dst->sin_family, 0); 1185 } 1186 } 1187