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_route.h" 38 #include "opt_mbuf_stress_test.h" 39 #include "opt_mpath.h" 40 #include "opt_sctp.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/kernel.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #include <sys/priv.h> 48 #include <sys/proc.h> 49 #include <sys/protosw.h> 50 #include <sys/socket.h> 51 #include <sys/socketvar.h> 52 #include <sys/sysctl.h> 53 #include <sys/ucred.h> 54 55 #include <net/if.h> 56 #include <net/if_llatbl.h> 57 #include <net/netisr.h> 58 #include <net/pfil.h> 59 #include <net/route.h> 60 #include <net/flowtable.h> 61 #ifdef RADIX_MPATH 62 #include <net/radix_mpath.h> 63 #endif 64 #include <net/vnet.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_systm.h> 68 #include <netinet/ip.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/in_var.h> 71 #include <netinet/ip_var.h> 72 #include <netinet/ip_options.h> 73 #ifdef SCTP 74 #include <netinet/sctp.h> 75 #include <netinet/sctp_crc32.h> 76 #endif 77 78 #ifdef IPSEC 79 #include <netinet/ip_ipsec.h> 80 #include <netipsec/ipsec.h> 81 #endif /* IPSEC*/ 82 83 #include <machine/in_cksum.h> 84 85 #include <security/mac/mac_framework.h> 86 87 #define print_ip(x, a, y) printf("%s %d.%d.%d.%d%s",\ 88 x, (ntohl(a.s_addr)>>24)&0xFF,\ 89 (ntohl(a.s_addr)>>16)&0xFF,\ 90 (ntohl(a.s_addr)>>8)&0xFF,\ 91 (ntohl(a.s_addr))&0xFF, y); 92 93 VNET_DEFINE(u_short, ip_id); 94 95 #ifdef MBUF_STRESS_TEST 96 int mbuf_frag_size = 0; 97 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 98 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 99 #endif 100 101 static void ip_mloopback 102 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 103 104 105 extern int in_mcast_loop; 106 extern struct protosw inetsw[]; 107 108 /* 109 * IP output. The packet in mbuf chain m contains a skeletal IP 110 * header (with len, off, ttl, proto, tos, src, dst). 111 * The mbuf chain containing the packet will be freed. 112 * The mbuf opt, if present, will not be freed. 113 * In the IP forwarding case, the packet will arrive with options already 114 * inserted, so must have a NULL opt pointer. 115 */ 116 int 117 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 118 struct ip_moptions *imo, struct inpcb *inp) 119 { 120 struct ip *ip; 121 struct ifnet *ifp = NULL; /* keep compiler happy */ 122 struct mbuf *m0; 123 int hlen = sizeof (struct ip); 124 int mtu; 125 int len, error = 0; 126 int nortfree = 0; 127 struct sockaddr_in *dst = NULL; /* keep compiler happy */ 128 struct in_ifaddr *ia = NULL; 129 int isbroadcast, sw_csum; 130 struct route iproute; 131 struct in_addr odst; 132 #ifdef IPFIREWALL_FORWARD 133 struct m_tag *fwd_tag = NULL; 134 #endif 135 #ifdef IPSEC 136 int no_route_but_check_spd = 0; 137 #endif 138 M_ASSERTPKTHDR(m); 139 140 if (inp != NULL) { 141 INP_LOCK_ASSERT(inp); 142 M_SETFIB(m, inp->inp_inc.inc_fibnum); 143 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) { 144 m->m_pkthdr.flowid = inp->inp_flowid; 145 m->m_flags |= M_FLOWID; 146 } 147 } 148 149 if (ro == NULL) { 150 ro = &iproute; 151 bzero(ro, sizeof (*ro)); 152 153 #ifdef FLOWTABLE 154 /* 155 * The flow table returns route entries valid for up to 30 156 * seconds; we rely on the remainder of ip_output() taking no 157 * longer than that long for the stability of ro_rt. The 158 * flow ID assignment must have happened before this point. 159 */ 160 if (flowtable_lookup(V_ip_ft, m, ro, M_GETFIB(m)) == 0) 161 nortfree = 1; 162 #endif 163 } 164 165 if (opt) { 166 len = 0; 167 m = ip_insertoptions(m, opt, &len); 168 if (len != 0) 169 hlen = len; 170 } 171 ip = mtod(m, struct ip *); 172 173 /* 174 * Fill in IP header. If we are not allowing fragmentation, 175 * then the ip_id field is meaningless, but we don't set it 176 * to zero. Doing so causes various problems when devices along 177 * the path (routers, load balancers, firewalls, etc.) illegally 178 * disable DF on our packet. Note that a 16-bit counter 179 * will wrap around in less than 10 seconds at 100 Mbit/s on a 180 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 181 * for Counting NATted Hosts", Proc. IMW'02, available at 182 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 183 */ 184 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 185 ip->ip_v = IPVERSION; 186 ip->ip_hl = hlen >> 2; 187 ip->ip_id = ip_newid(); 188 IPSTAT_INC(ips_localout); 189 } else { 190 hlen = ip->ip_hl << 2; 191 } 192 193 dst = (struct sockaddr_in *)&ro->ro_dst; 194 again: 195 /* 196 * If there is a cached route, 197 * check that it is to the same destination 198 * and is still up. If not, free it and try again. 199 * The address family should also be checked in case of sharing the 200 * cache with IPv6. 201 */ 202 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 203 dst->sin_family != AF_INET || 204 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 205 if (!nortfree) { 206 RTFREE(ro->ro_rt); 207 LLE_FREE(ro->ro_lle); 208 } 209 ro->ro_rt = (struct rtentry *)NULL; 210 ro->ro_lle = (struct llentry *)NULL; 211 } 212 #ifdef IPFIREWALL_FORWARD 213 if (ro->ro_rt == NULL && fwd_tag == NULL) { 214 #else 215 if (ro->ro_rt == NULL) { 216 #endif 217 bzero(dst, sizeof(*dst)); 218 dst->sin_family = AF_INET; 219 dst->sin_len = sizeof(*dst); 220 dst->sin_addr = ip->ip_dst; 221 } 222 /* 223 * If routing to interface only, short circuit routing lookup. 224 * The use of an all-ones broadcast address implies this; an 225 * interface is specified by the broadcast address of an interface, 226 * or the destination address of a ptp interface. 227 */ 228 if (flags & IP_SENDONES) { 229 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 230 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 231 IPSTAT_INC(ips_noroute); 232 error = ENETUNREACH; 233 goto bad; 234 } 235 ip->ip_dst.s_addr = INADDR_BROADCAST; 236 dst->sin_addr = ip->ip_dst; 237 ifp = ia->ia_ifp; 238 ip->ip_ttl = 1; 239 isbroadcast = 1; 240 } else if (flags & IP_ROUTETOIF) { 241 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 242 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) { 243 IPSTAT_INC(ips_noroute); 244 error = ENETUNREACH; 245 goto bad; 246 } 247 ifp = ia->ia_ifp; 248 ip->ip_ttl = 1; 249 isbroadcast = in_broadcast(dst->sin_addr, ifp); 250 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 251 imo != NULL && imo->imo_multicast_ifp != NULL) { 252 /* 253 * Bypass the normal routing lookup for multicast 254 * packets if the interface is specified. 255 */ 256 ifp = imo->imo_multicast_ifp; 257 IFP_TO_IA(ifp, ia); 258 isbroadcast = 0; /* fool gcc */ 259 } else { 260 /* 261 * We want to do any cloning requested by the link layer, 262 * as this is probably required in all cases for correct 263 * operation (as it is for ARP). 264 */ 265 if (ro->ro_rt == NULL) 266 #ifdef RADIX_MPATH 267 rtalloc_mpath_fib(ro, 268 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 269 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 270 #else 271 in_rtalloc_ign(ro, 0, 272 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 273 #endif 274 if (ro->ro_rt == NULL) { 275 #ifdef IPSEC 276 /* 277 * There is no route for this packet, but it is 278 * possible that a matching SPD entry exists. 279 */ 280 no_route_but_check_spd = 1; 281 mtu = 0; /* Silence GCC warning. */ 282 goto sendit; 283 #endif 284 IPSTAT_INC(ips_noroute); 285 error = EHOSTUNREACH; 286 goto bad; 287 } 288 ia = ifatoia(ro->ro_rt->rt_ifa); 289 ifa_ref(&ia->ia_ifa); 290 ifp = ro->ro_rt->rt_ifp; 291 ro->ro_rt->rt_rmx.rmx_pksent++; 292 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 293 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 294 if (ro->ro_rt->rt_flags & RTF_HOST) 295 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST); 296 else 297 isbroadcast = in_broadcast(dst->sin_addr, ifp); 298 } 299 /* 300 * Calculate MTU. If we have a route that is up, use that, 301 * otherwise use the interface's MTU. 302 */ 303 if (ro->ro_rt != NULL && (ro->ro_rt->rt_flags & (RTF_UP|RTF_HOST))) { 304 /* 305 * This case can happen if the user changed the MTU 306 * of an interface after enabling IP on it. Because 307 * most netifs don't keep track of routes pointing to 308 * them, there is no way for one to update all its 309 * routes when the MTU is changed. 310 */ 311 if (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu) 312 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu; 313 mtu = ro->ro_rt->rt_rmx.rmx_mtu; 314 } else { 315 mtu = ifp->if_mtu; 316 } 317 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 318 m->m_flags |= M_MCAST; 319 /* 320 * IP destination address is multicast. Make sure "dst" 321 * still points to the address in "ro". (It may have been 322 * changed to point to a gateway address, above.) 323 */ 324 dst = (struct sockaddr_in *)&ro->ro_dst; 325 /* 326 * See if the caller provided any multicast options 327 */ 328 if (imo != NULL) { 329 ip->ip_ttl = imo->imo_multicast_ttl; 330 if (imo->imo_multicast_vif != -1) 331 ip->ip_src.s_addr = 332 ip_mcast_src ? 333 ip_mcast_src(imo->imo_multicast_vif) : 334 INADDR_ANY; 335 } else 336 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 337 /* 338 * Confirm that the outgoing interface supports multicast. 339 */ 340 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 341 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 342 IPSTAT_INC(ips_noroute); 343 error = ENETUNREACH; 344 goto bad; 345 } 346 } 347 /* 348 * If source address not specified yet, use address 349 * of outgoing interface. 350 */ 351 if (ip->ip_src.s_addr == INADDR_ANY) { 352 /* Interface may have no addresses. */ 353 if (ia != NULL) 354 ip->ip_src = IA_SIN(ia)->sin_addr; 355 } 356 357 if ((imo == NULL && in_mcast_loop) || 358 (imo && imo->imo_multicast_loop)) { 359 /* 360 * Loop back multicast datagram if not expressly 361 * forbidden to do so, even if we are not a member 362 * of the group; ip_input() will filter it later, 363 * thus deferring a hash lookup and mutex acquisition 364 * at the expense of a cheap copy using m_copym(). 365 */ 366 ip_mloopback(ifp, m, dst, hlen); 367 } else { 368 /* 369 * If we are acting as a multicast router, perform 370 * multicast forwarding as if the packet had just 371 * arrived on the interface to which we are about 372 * to send. The multicast forwarding function 373 * recursively calls this function, using the 374 * IP_FORWARDING flag to prevent infinite recursion. 375 * 376 * Multicasts that are looped back by ip_mloopback(), 377 * above, will be forwarded by the ip_input() routine, 378 * if necessary. 379 */ 380 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) { 381 /* 382 * If rsvp daemon is not running, do not 383 * set ip_moptions. This ensures that the packet 384 * is multicast and not just sent down one link 385 * as prescribed by rsvpd. 386 */ 387 if (!V_rsvp_on) 388 imo = NULL; 389 if (ip_mforward && 390 ip_mforward(ip, ifp, m, imo) != 0) { 391 m_freem(m); 392 goto done; 393 } 394 } 395 } 396 397 /* 398 * Multicasts with a time-to-live of zero may be looped- 399 * back, above, but must not be transmitted on a network. 400 * Also, multicasts addressed to the loopback interface 401 * are not sent -- the above call to ip_mloopback() will 402 * loop back a copy. ip_input() will drop the copy if 403 * this host does not belong to the destination group on 404 * the loopback interface. 405 */ 406 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 407 m_freem(m); 408 goto done; 409 } 410 411 goto sendit; 412 } 413 414 /* 415 * If the source address is not specified yet, use the address 416 * of the outoing interface. 417 */ 418 if (ip->ip_src.s_addr == INADDR_ANY) { 419 /* Interface may have no addresses. */ 420 if (ia != NULL) { 421 ip->ip_src = IA_SIN(ia)->sin_addr; 422 } 423 } 424 425 /* 426 * Verify that we have any chance at all of being able to queue the 427 * packet or packet fragments, unless ALTQ is enabled on the given 428 * interface in which case packetdrop should be done by queueing. 429 */ 430 #ifdef ALTQ 431 if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) && 432 ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 433 ifp->if_snd.ifq_maxlen)) 434 #else 435 if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 436 ifp->if_snd.ifq_maxlen) 437 #endif /* ALTQ */ 438 { 439 error = ENOBUFS; 440 IPSTAT_INC(ips_odropped); 441 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1); 442 goto bad; 443 } 444 445 /* 446 * Look for broadcast address and 447 * verify user is allowed to send 448 * such a packet. 449 */ 450 if (isbroadcast) { 451 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 452 error = EADDRNOTAVAIL; 453 goto bad; 454 } 455 if ((flags & IP_ALLOWBROADCAST) == 0) { 456 error = EACCES; 457 goto bad; 458 } 459 /* don't allow broadcast messages to be fragmented */ 460 if (ip->ip_len > mtu) { 461 error = EMSGSIZE; 462 goto bad; 463 } 464 m->m_flags |= M_BCAST; 465 } else { 466 m->m_flags &= ~M_BCAST; 467 } 468 469 sendit: 470 #ifdef IPSEC 471 switch(ip_ipsec_output(&m, inp, &flags, &error, &ifp)) { 472 case 1: 473 goto bad; 474 case -1: 475 goto done; 476 case 0: 477 default: 478 break; /* Continue with packet processing. */ 479 } 480 /* 481 * Check if there was a route for this packet; return error if not. 482 */ 483 if (no_route_but_check_spd) { 484 IPSTAT_INC(ips_noroute); 485 error = EHOSTUNREACH; 486 goto bad; 487 } 488 /* Update variables that are affected by ipsec4_output(). */ 489 ip = mtod(m, struct ip *); 490 hlen = ip->ip_hl << 2; 491 #endif /* IPSEC */ 492 493 /* Jump over all PFIL processing if hooks are not active. */ 494 if (!PFIL_HOOKED(&inet_pfil_hook)) 495 goto passout; 496 497 /* Run through list of hooks for output packets. */ 498 odst.s_addr = ip->ip_dst.s_addr; 499 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 500 if (error != 0 || m == NULL) 501 goto done; 502 503 ip = mtod(m, struct ip *); 504 505 /* See if destination IP address was changed by packet filter. */ 506 if (odst.s_addr != ip->ip_dst.s_addr) { 507 m->m_flags |= M_SKIP_FIREWALL; 508 /* If destination is now ourself drop to ip_input(). */ 509 if (in_localip(ip->ip_dst)) { 510 m->m_flags |= M_FASTFWD_OURS; 511 if (m->m_pkthdr.rcvif == NULL) 512 m->m_pkthdr.rcvif = V_loif; 513 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 514 m->m_pkthdr.csum_flags |= 515 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 516 m->m_pkthdr.csum_data = 0xffff; 517 } 518 m->m_pkthdr.csum_flags |= 519 CSUM_IP_CHECKED | CSUM_IP_VALID; 520 #ifdef SCTP 521 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 522 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 523 #endif 524 error = netisr_queue(NETISR_IP, m); 525 goto done; 526 } else 527 goto again; /* Redo the routing table lookup. */ 528 } 529 530 #ifdef IPFIREWALL_FORWARD 531 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 532 if (m->m_flags & M_FASTFWD_OURS) { 533 if (m->m_pkthdr.rcvif == NULL) 534 m->m_pkthdr.rcvif = V_loif; 535 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 536 m->m_pkthdr.csum_flags |= 537 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 538 m->m_pkthdr.csum_data = 0xffff; 539 } 540 #ifdef SCTP 541 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 542 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 543 #endif 544 m->m_pkthdr.csum_flags |= 545 CSUM_IP_CHECKED | CSUM_IP_VALID; 546 547 error = netisr_queue(NETISR_IP, m); 548 goto done; 549 } 550 /* Or forward to some other address? */ 551 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 552 if (fwd_tag) { 553 dst = (struct sockaddr_in *)&ro->ro_dst; 554 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 555 m->m_flags |= M_SKIP_FIREWALL; 556 m_tag_delete(m, fwd_tag); 557 goto again; 558 } 559 #endif /* IPFIREWALL_FORWARD */ 560 561 passout: 562 /* 127/8 must not appear on wire - RFC1122. */ 563 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 564 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 565 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 566 IPSTAT_INC(ips_badaddr); 567 error = EADDRNOTAVAIL; 568 goto bad; 569 } 570 } 571 572 m->m_pkthdr.csum_flags |= CSUM_IP; 573 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 574 if (sw_csum & CSUM_DELAY_DATA) { 575 in_delayed_cksum(m); 576 sw_csum &= ~CSUM_DELAY_DATA; 577 } 578 #ifdef SCTP 579 if (sw_csum & CSUM_SCTP) { 580 sctp_delayed_cksum(m); 581 sw_csum &= ~CSUM_SCTP; 582 } 583 #endif 584 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 585 586 /* 587 * If small enough for interface, or the interface will take 588 * care of the fragmentation for us, we can just send directly. 589 */ 590 if (ip->ip_len <= mtu || 591 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 592 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 593 ip->ip_len = htons(ip->ip_len); 594 ip->ip_off = htons(ip->ip_off); 595 ip->ip_sum = 0; 596 if (sw_csum & CSUM_DELAY_IP) 597 ip->ip_sum = in_cksum(m, hlen); 598 599 /* 600 * Record statistics for this interface address. 601 * With CSUM_TSO the byte/packet count will be slightly 602 * incorrect because we count the IP+TCP headers only 603 * once instead of for every generated packet. 604 */ 605 if (!(flags & IP_FORWARDING) && ia) { 606 if (m->m_pkthdr.csum_flags & CSUM_TSO) 607 ia->ia_ifa.if_opackets += 608 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 609 else 610 ia->ia_ifa.if_opackets++; 611 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 612 } 613 #ifdef MBUF_STRESS_TEST 614 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 615 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 616 #endif 617 /* 618 * Reset layer specific mbuf flags 619 * to avoid confusing lower layers. 620 */ 621 m->m_flags &= ~(M_PROTOFLAGS); 622 error = (*ifp->if_output)(ifp, m, 623 (struct sockaddr *)dst, ro); 624 goto done; 625 } 626 627 /* Balk when DF bit is set or the interface didn't support TSO. */ 628 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 629 error = EMSGSIZE; 630 IPSTAT_INC(ips_cantfrag); 631 goto bad; 632 } 633 634 /* 635 * Too large for interface; fragment if possible. If successful, 636 * on return, m will point to a list of packets to be sent. 637 */ 638 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 639 if (error) 640 goto bad; 641 for (; m; m = m0) { 642 m0 = m->m_nextpkt; 643 m->m_nextpkt = 0; 644 if (error == 0) { 645 /* Record statistics for this interface address. */ 646 if (ia != NULL) { 647 ia->ia_ifa.if_opackets++; 648 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 649 } 650 /* 651 * Reset layer specific mbuf flags 652 * to avoid confusing upper layers. 653 */ 654 m->m_flags &= ~(M_PROTOFLAGS); 655 656 error = (*ifp->if_output)(ifp, m, 657 (struct sockaddr *)dst, ro); 658 } else 659 m_freem(m); 660 } 661 662 if (error == 0) 663 IPSTAT_INC(ips_fragmented); 664 665 done: 666 if (ro == &iproute && ro->ro_rt && !nortfree) { 667 RTFREE(ro->ro_rt); 668 } 669 if (ia != NULL) 670 ifa_free(&ia->ia_ifa); 671 return (error); 672 bad: 673 m_freem(m); 674 goto done; 675 } 676 677 /* 678 * Create a chain of fragments which fit the given mtu. m_frag points to the 679 * mbuf to be fragmented; on return it points to the chain with the fragments. 680 * Return 0 if no error. If error, m_frag may contain a partially built 681 * chain of fragments that should be freed by the caller. 682 * 683 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 684 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 685 */ 686 int 687 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 688 u_long if_hwassist_flags, int sw_csum) 689 { 690 int error = 0; 691 int hlen = ip->ip_hl << 2; 692 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 693 int off; 694 struct mbuf *m0 = *m_frag; /* the original packet */ 695 int firstlen; 696 struct mbuf **mnext; 697 int nfrags; 698 699 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */ 700 IPSTAT_INC(ips_cantfrag); 701 return EMSGSIZE; 702 } 703 704 /* 705 * Must be able to put at least 8 bytes per fragment. 706 */ 707 if (len < 8) 708 return EMSGSIZE; 709 710 /* 711 * If the interface will not calculate checksums on 712 * fragmented packets, then do it here. 713 */ 714 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 715 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 716 in_delayed_cksum(m0); 717 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 718 } 719 #ifdef SCTP 720 if (m0->m_pkthdr.csum_flags & CSUM_SCTP && 721 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 722 sctp_delayed_cksum(m0); 723 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP; 724 } 725 #endif 726 if (len > PAGE_SIZE) { 727 /* 728 * Fragment large datagrams such that each segment 729 * contains a multiple of PAGE_SIZE amount of data, 730 * plus headers. This enables a receiver to perform 731 * page-flipping zero-copy optimizations. 732 * 733 * XXX When does this help given that sender and receiver 734 * could have different page sizes, and also mtu could 735 * be less than the receiver's page size ? 736 */ 737 int newlen; 738 struct mbuf *m; 739 740 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 741 off += m->m_len; 742 743 /* 744 * firstlen (off - hlen) must be aligned on an 745 * 8-byte boundary 746 */ 747 if (off < hlen) 748 goto smart_frag_failure; 749 off = ((off - hlen) & ~7) + hlen; 750 newlen = (~PAGE_MASK) & mtu; 751 if ((newlen + sizeof (struct ip)) > mtu) { 752 /* we failed, go back the default */ 753 smart_frag_failure: 754 newlen = len; 755 off = hlen + len; 756 } 757 len = newlen; 758 759 } else { 760 off = hlen + len; 761 } 762 763 firstlen = off - hlen; 764 mnext = &m0->m_nextpkt; /* pointer to next packet */ 765 766 /* 767 * Loop through length of segment after first fragment, 768 * make new header and copy data of each part and link onto chain. 769 * Here, m0 is the original packet, m is the fragment being created. 770 * The fragments are linked off the m_nextpkt of the original 771 * packet, which after processing serves as the first fragment. 772 */ 773 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) { 774 struct ip *mhip; /* ip header on the fragment */ 775 struct mbuf *m; 776 int mhlen = sizeof (struct ip); 777 778 MGETHDR(m, M_DONTWAIT, MT_DATA); 779 if (m == NULL) { 780 error = ENOBUFS; 781 IPSTAT_INC(ips_odropped); 782 goto done; 783 } 784 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 785 /* 786 * In the first mbuf, leave room for the link header, then 787 * copy the original IP header including options. The payload 788 * goes into an additional mbuf chain returned by m_copym(). 789 */ 790 m->m_data += max_linkhdr; 791 mhip = mtod(m, struct ip *); 792 *mhip = *ip; 793 if (hlen > sizeof (struct ip)) { 794 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 795 mhip->ip_v = IPVERSION; 796 mhip->ip_hl = mhlen >> 2; 797 } 798 m->m_len = mhlen; 799 /* XXX do we need to add ip->ip_off below ? */ 800 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off; 801 if (off + len >= ip->ip_len) { /* last fragment */ 802 len = ip->ip_len - off; 803 m->m_flags |= M_LASTFRAG; 804 } else 805 mhip->ip_off |= IP_MF; 806 mhip->ip_len = htons((u_short)(len + mhlen)); 807 m->m_next = m_copym(m0, off, len, M_DONTWAIT); 808 if (m->m_next == NULL) { /* copy failed */ 809 m_free(m); 810 error = ENOBUFS; /* ??? */ 811 IPSTAT_INC(ips_odropped); 812 goto done; 813 } 814 m->m_pkthdr.len = mhlen + len; 815 m->m_pkthdr.rcvif = NULL; 816 #ifdef MAC 817 mac_netinet_fragment(m0, m); 818 #endif 819 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 820 mhip->ip_off = htons(mhip->ip_off); 821 mhip->ip_sum = 0; 822 if (sw_csum & CSUM_DELAY_IP) 823 mhip->ip_sum = in_cksum(m, mhlen); 824 *mnext = m; 825 mnext = &m->m_nextpkt; 826 } 827 IPSTAT_ADD(ips_ofragments, nfrags); 828 829 /* set first marker for fragment chain */ 830 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 831 m0->m_pkthdr.csum_data = nfrags; 832 833 /* 834 * Update first fragment by trimming what's been copied out 835 * and updating header. 836 */ 837 m_adj(m0, hlen + firstlen - ip->ip_len); 838 m0->m_pkthdr.len = hlen + firstlen; 839 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 840 ip->ip_off |= IP_MF; 841 ip->ip_off = htons(ip->ip_off); 842 ip->ip_sum = 0; 843 if (sw_csum & CSUM_DELAY_IP) 844 ip->ip_sum = in_cksum(m0, hlen); 845 846 done: 847 *m_frag = m0; 848 return error; 849 } 850 851 void 852 in_delayed_cksum(struct mbuf *m) 853 { 854 struct ip *ip; 855 u_short csum, offset; 856 857 ip = mtod(m, struct ip *); 858 offset = ip->ip_hl << 2 ; 859 csum = in_cksum_skip(m, ip->ip_len, offset); 860 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 861 csum = 0xffff; 862 offset += m->m_pkthdr.csum_data; /* checksum offset */ 863 864 if (offset + sizeof(u_short) > m->m_len) { 865 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 866 m->m_len, offset, ip->ip_p); 867 /* 868 * XXX 869 * this shouldn't happen, but if it does, the 870 * correct behavior may be to insert the checksum 871 * in the appropriate next mbuf in the chain. 872 */ 873 return; 874 } 875 *(u_short *)(m->m_data + offset) = csum; 876 } 877 878 /* 879 * IP socket option processing. 880 */ 881 int 882 ip_ctloutput(struct socket *so, struct sockopt *sopt) 883 { 884 struct inpcb *inp = sotoinpcb(so); 885 int error, optval; 886 887 error = optval = 0; 888 if (sopt->sopt_level != IPPROTO_IP) { 889 if ((sopt->sopt_level == SOL_SOCKET) && 890 (sopt->sopt_name == SO_SETFIB)) { 891 inp->inp_inc.inc_fibnum = so->so_fibnum; 892 return (0); 893 } 894 return (EINVAL); 895 } 896 897 switch (sopt->sopt_dir) { 898 case SOPT_SET: 899 switch (sopt->sopt_name) { 900 case IP_OPTIONS: 901 #ifdef notyet 902 case IP_RETOPTS: 903 #endif 904 { 905 struct mbuf *m; 906 if (sopt->sopt_valsize > MLEN) { 907 error = EMSGSIZE; 908 break; 909 } 910 MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, MT_DATA); 911 if (m == NULL) { 912 error = ENOBUFS; 913 break; 914 } 915 m->m_len = sopt->sopt_valsize; 916 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 917 m->m_len); 918 if (error) { 919 m_free(m); 920 break; 921 } 922 INP_WLOCK(inp); 923 error = ip_pcbopts(inp, sopt->sopt_name, m); 924 INP_WUNLOCK(inp); 925 return (error); 926 } 927 928 case IP_BINDANY: 929 if (sopt->sopt_td != NULL) { 930 error = priv_check(sopt->sopt_td, 931 PRIV_NETINET_BINDANY); 932 if (error) 933 break; 934 } 935 /* FALLTHROUGH */ 936 case IP_TOS: 937 case IP_TTL: 938 case IP_MINTTL: 939 case IP_RECVOPTS: 940 case IP_RECVRETOPTS: 941 case IP_RECVDSTADDR: 942 case IP_RECVTTL: 943 case IP_RECVIF: 944 case IP_FAITH: 945 case IP_ONESBCAST: 946 case IP_DONTFRAG: 947 error = sooptcopyin(sopt, &optval, sizeof optval, 948 sizeof optval); 949 if (error) 950 break; 951 952 switch (sopt->sopt_name) { 953 case IP_TOS: 954 inp->inp_ip_tos = optval; 955 break; 956 957 case IP_TTL: 958 inp->inp_ip_ttl = optval; 959 break; 960 961 case IP_MINTTL: 962 if (optval >= 0 && optval <= MAXTTL) 963 inp->inp_ip_minttl = optval; 964 else 965 error = EINVAL; 966 break; 967 968 #define OPTSET(bit) do { \ 969 INP_WLOCK(inp); \ 970 if (optval) \ 971 inp->inp_flags |= bit; \ 972 else \ 973 inp->inp_flags &= ~bit; \ 974 INP_WUNLOCK(inp); \ 975 } while (0) 976 977 case IP_RECVOPTS: 978 OPTSET(INP_RECVOPTS); 979 break; 980 981 case IP_RECVRETOPTS: 982 OPTSET(INP_RECVRETOPTS); 983 break; 984 985 case IP_RECVDSTADDR: 986 OPTSET(INP_RECVDSTADDR); 987 break; 988 989 case IP_RECVTTL: 990 OPTSET(INP_RECVTTL); 991 break; 992 993 case IP_RECVIF: 994 OPTSET(INP_RECVIF); 995 break; 996 997 case IP_FAITH: 998 OPTSET(INP_FAITH); 999 break; 1000 1001 case IP_ONESBCAST: 1002 OPTSET(INP_ONESBCAST); 1003 break; 1004 case IP_DONTFRAG: 1005 OPTSET(INP_DONTFRAG); 1006 break; 1007 case IP_BINDANY: 1008 OPTSET(INP_BINDANY); 1009 break; 1010 } 1011 break; 1012 #undef OPTSET 1013 1014 /* 1015 * Multicast socket options are processed by the in_mcast 1016 * module. 1017 */ 1018 case IP_MULTICAST_IF: 1019 case IP_MULTICAST_VIF: 1020 case IP_MULTICAST_TTL: 1021 case IP_MULTICAST_LOOP: 1022 case IP_ADD_MEMBERSHIP: 1023 case IP_DROP_MEMBERSHIP: 1024 case IP_ADD_SOURCE_MEMBERSHIP: 1025 case IP_DROP_SOURCE_MEMBERSHIP: 1026 case IP_BLOCK_SOURCE: 1027 case IP_UNBLOCK_SOURCE: 1028 case IP_MSFILTER: 1029 case MCAST_JOIN_GROUP: 1030 case MCAST_LEAVE_GROUP: 1031 case MCAST_JOIN_SOURCE_GROUP: 1032 case MCAST_LEAVE_SOURCE_GROUP: 1033 case MCAST_BLOCK_SOURCE: 1034 case MCAST_UNBLOCK_SOURCE: 1035 error = inp_setmoptions(inp, sopt); 1036 break; 1037 1038 case IP_PORTRANGE: 1039 error = sooptcopyin(sopt, &optval, sizeof optval, 1040 sizeof optval); 1041 if (error) 1042 break; 1043 1044 INP_WLOCK(inp); 1045 switch (optval) { 1046 case IP_PORTRANGE_DEFAULT: 1047 inp->inp_flags &= ~(INP_LOWPORT); 1048 inp->inp_flags &= ~(INP_HIGHPORT); 1049 break; 1050 1051 case IP_PORTRANGE_HIGH: 1052 inp->inp_flags &= ~(INP_LOWPORT); 1053 inp->inp_flags |= INP_HIGHPORT; 1054 break; 1055 1056 case IP_PORTRANGE_LOW: 1057 inp->inp_flags &= ~(INP_HIGHPORT); 1058 inp->inp_flags |= INP_LOWPORT; 1059 break; 1060 1061 default: 1062 error = EINVAL; 1063 break; 1064 } 1065 INP_WUNLOCK(inp); 1066 break; 1067 1068 #ifdef IPSEC 1069 case IP_IPSEC_POLICY: 1070 { 1071 caddr_t req; 1072 struct mbuf *m; 1073 1074 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 1075 break; 1076 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 1077 break; 1078 req = mtod(m, caddr_t); 1079 error = ipsec_set_policy(inp, sopt->sopt_name, req, 1080 m->m_len, (sopt->sopt_td != NULL) ? 1081 sopt->sopt_td->td_ucred : NULL); 1082 m_freem(m); 1083 break; 1084 } 1085 #endif /* IPSEC */ 1086 1087 default: 1088 error = ENOPROTOOPT; 1089 break; 1090 } 1091 break; 1092 1093 case SOPT_GET: 1094 switch (sopt->sopt_name) { 1095 case IP_OPTIONS: 1096 case IP_RETOPTS: 1097 if (inp->inp_options) 1098 error = sooptcopyout(sopt, 1099 mtod(inp->inp_options, 1100 char *), 1101 inp->inp_options->m_len); 1102 else 1103 sopt->sopt_valsize = 0; 1104 break; 1105 1106 case IP_TOS: 1107 case IP_TTL: 1108 case IP_MINTTL: 1109 case IP_RECVOPTS: 1110 case IP_RECVRETOPTS: 1111 case IP_RECVDSTADDR: 1112 case IP_RECVTTL: 1113 case IP_RECVIF: 1114 case IP_PORTRANGE: 1115 case IP_FAITH: 1116 case IP_ONESBCAST: 1117 case IP_DONTFRAG: 1118 switch (sopt->sopt_name) { 1119 1120 case IP_TOS: 1121 optval = inp->inp_ip_tos; 1122 break; 1123 1124 case IP_TTL: 1125 optval = inp->inp_ip_ttl; 1126 break; 1127 1128 case IP_MINTTL: 1129 optval = inp->inp_ip_minttl; 1130 break; 1131 1132 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1133 1134 case IP_RECVOPTS: 1135 optval = OPTBIT(INP_RECVOPTS); 1136 break; 1137 1138 case IP_RECVRETOPTS: 1139 optval = OPTBIT(INP_RECVRETOPTS); 1140 break; 1141 1142 case IP_RECVDSTADDR: 1143 optval = OPTBIT(INP_RECVDSTADDR); 1144 break; 1145 1146 case IP_RECVTTL: 1147 optval = OPTBIT(INP_RECVTTL); 1148 break; 1149 1150 case IP_RECVIF: 1151 optval = OPTBIT(INP_RECVIF); 1152 break; 1153 1154 case IP_PORTRANGE: 1155 if (inp->inp_flags & INP_HIGHPORT) 1156 optval = IP_PORTRANGE_HIGH; 1157 else if (inp->inp_flags & INP_LOWPORT) 1158 optval = IP_PORTRANGE_LOW; 1159 else 1160 optval = 0; 1161 break; 1162 1163 case IP_FAITH: 1164 optval = OPTBIT(INP_FAITH); 1165 break; 1166 1167 case IP_ONESBCAST: 1168 optval = OPTBIT(INP_ONESBCAST); 1169 break; 1170 case IP_DONTFRAG: 1171 optval = OPTBIT(INP_DONTFRAG); 1172 break; 1173 } 1174 error = sooptcopyout(sopt, &optval, sizeof optval); 1175 break; 1176 1177 /* 1178 * Multicast socket options are processed by the in_mcast 1179 * module. 1180 */ 1181 case IP_MULTICAST_IF: 1182 case IP_MULTICAST_VIF: 1183 case IP_MULTICAST_TTL: 1184 case IP_MULTICAST_LOOP: 1185 case IP_MSFILTER: 1186 error = inp_getmoptions(inp, sopt); 1187 break; 1188 1189 #ifdef IPSEC 1190 case IP_IPSEC_POLICY: 1191 { 1192 struct mbuf *m = NULL; 1193 caddr_t req = NULL; 1194 size_t len = 0; 1195 1196 if (m != 0) { 1197 req = mtod(m, caddr_t); 1198 len = m->m_len; 1199 } 1200 error = ipsec_get_policy(sotoinpcb(so), req, len, &m); 1201 if (error == 0) 1202 error = soopt_mcopyout(sopt, m); /* XXX */ 1203 if (error == 0) 1204 m_freem(m); 1205 break; 1206 } 1207 #endif /* IPSEC */ 1208 1209 default: 1210 error = ENOPROTOOPT; 1211 break; 1212 } 1213 break; 1214 } 1215 return (error); 1216 } 1217 1218 /* 1219 * Routine called from ip_output() to loop back a copy of an IP multicast 1220 * packet to the input queue of a specified interface. Note that this 1221 * calls the output routine of the loopback "driver", but with an interface 1222 * pointer that might NOT be a loopback interface -- evil, but easier than 1223 * replicating that code here. 1224 */ 1225 static void 1226 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1227 int hlen) 1228 { 1229 register struct ip *ip; 1230 struct mbuf *copym; 1231 1232 /* 1233 * Make a deep copy of the packet because we're going to 1234 * modify the pack in order to generate checksums. 1235 */ 1236 copym = m_dup(m, M_DONTWAIT); 1237 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1238 copym = m_pullup(copym, hlen); 1239 if (copym != NULL) { 1240 /* If needed, compute the checksum and mark it as valid. */ 1241 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1242 in_delayed_cksum(copym); 1243 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1244 copym->m_pkthdr.csum_flags |= 1245 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1246 copym->m_pkthdr.csum_data = 0xffff; 1247 } 1248 /* 1249 * We don't bother to fragment if the IP length is greater 1250 * than the interface's MTU. Can this possibly matter? 1251 */ 1252 ip = mtod(copym, struct ip *); 1253 ip->ip_len = htons(ip->ip_len); 1254 ip->ip_off = htons(ip->ip_off); 1255 ip->ip_sum = 0; 1256 ip->ip_sum = in_cksum(copym, hlen); 1257 #if 1 /* XXX */ 1258 if (dst->sin_family != AF_INET) { 1259 printf("ip_mloopback: bad address family %d\n", 1260 dst->sin_family); 1261 dst->sin_family = AF_INET; 1262 } 1263 #endif 1264 if_simloop(ifp, copym, dst->sin_family, 0); 1265 } 1266 } 1267