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 VNET_DEFINE(u_short, ip_id); 88 89 #ifdef MBUF_STRESS_TEST 90 int mbuf_frag_size = 0; 91 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 92 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 93 #endif 94 95 static void ip_mloopback 96 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 97 98 99 extern int in_mcast_loop; 100 extern struct protosw inetsw[]; 101 102 /* 103 * IP output. The packet in mbuf chain m contains a skeletal IP 104 * header (with len, off, ttl, proto, tos, src, dst). 105 * ip_len and ip_off are in host format. 106 * The mbuf chain containing the packet will be freed. 107 * The mbuf opt, if present, will not be freed. 108 * In the IP forwarding case, the packet will arrive with options already 109 * inserted, so must have a NULL opt pointer. 110 */ 111 int 112 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 113 struct ip_moptions *imo, struct inpcb *inp) 114 { 115 struct ip *ip; 116 struct ifnet *ifp = NULL; /* keep compiler happy */ 117 struct mbuf *m0; 118 int hlen = sizeof (struct ip); 119 int mtu; 120 int n; /* scratchpad */ 121 int error = 0; 122 int nortfree = 0; 123 struct sockaddr_in *dst; 124 struct in_ifaddr *ia = NULL; 125 int isbroadcast, sw_csum; 126 struct route iproute; 127 struct rtentry *rte; /* cache for ro->ro_rt */ 128 struct in_addr odst; 129 #ifdef IPFIREWALL_FORWARD 130 struct m_tag *fwd_tag = NULL; 131 #endif 132 #ifdef IPSEC 133 int no_route_but_check_spd = 0; 134 #endif 135 M_ASSERTPKTHDR(m); 136 137 if (inp != NULL) { 138 INP_LOCK_ASSERT(inp); 139 M_SETFIB(m, inp->inp_inc.inc_fibnum); 140 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) { 141 m->m_pkthdr.flowid = inp->inp_flowid; 142 m->m_flags |= M_FLOWID; 143 } 144 } 145 146 if (ro == NULL) { 147 ro = &iproute; 148 bzero(ro, sizeof (*ro)); 149 150 #ifdef FLOWTABLE 151 { 152 struct flentry *fle; 153 154 /* 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 ((fle = flowtable_lookup_mbuf(V_ip_ft, m, AF_INET)) != NULL) { 161 flow_to_route(fle, ro); 162 nortfree = 1; 163 } 164 } 165 #endif 166 } 167 168 if (opt) { 169 int len = 0; 170 m = ip_insertoptions(m, opt, &len); 171 if (len != 0) 172 hlen = len; /* ip->ip_hl is updated above */ 173 } 174 ip = mtod(m, struct ip *); 175 176 /* 177 * Fill in IP header. If we are not allowing fragmentation, 178 * then the ip_id field is meaningless, but we don't set it 179 * to zero. Doing so causes various problems when devices along 180 * the path (routers, load balancers, firewalls, etc.) illegally 181 * disable DF on our packet. Note that a 16-bit counter 182 * will wrap around in less than 10 seconds at 100 Mbit/s on a 183 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 184 * for Counting NATted Hosts", Proc. IMW'02, available at 185 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 186 */ 187 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 188 ip->ip_v = IPVERSION; 189 ip->ip_hl = hlen >> 2; 190 ip->ip_id = ip_newid(); 191 IPSTAT_INC(ips_localout); 192 } else { 193 /* Header already set, fetch hlen from there */ 194 hlen = ip->ip_hl << 2; 195 } 196 197 dst = (struct sockaddr_in *)&ro->ro_dst; 198 again: 199 /* 200 * If there is a cached route, 201 * check that it is to the same destination 202 * and is still up. If not, free it and try again. 203 * The address family should also be checked in case of sharing the 204 * cache with IPv6. 205 */ 206 rte = ro->ro_rt; 207 if (rte && ((rte->rt_flags & RTF_UP) == 0 || 208 rte->rt_ifp == NULL || 209 !RT_LINK_IS_UP(rte->rt_ifp) || 210 dst->sin_family != AF_INET || 211 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 212 if (!nortfree) 213 RTFREE(rte); 214 rte = ro->ro_rt = (struct rtentry *)NULL; 215 ro->ro_lle = (struct llentry *)NULL; 216 } 217 #ifdef IPFIREWALL_FORWARD 218 if (rte == NULL && fwd_tag == NULL) { 219 #else 220 if (rte == NULL) { 221 #endif 222 bzero(dst, sizeof(*dst)); 223 dst->sin_family = AF_INET; 224 dst->sin_len = sizeof(*dst); 225 dst->sin_addr = ip->ip_dst; 226 } 227 /* 228 * If routing to interface only, short circuit routing lookup. 229 * The use of an all-ones broadcast address implies this; an 230 * interface is specified by the broadcast address of an interface, 231 * or the destination address of a ptp interface. 232 */ 233 if (flags & IP_SENDONES) { 234 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 235 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 236 IPSTAT_INC(ips_noroute); 237 error = ENETUNREACH; 238 goto bad; 239 } 240 ip->ip_dst.s_addr = INADDR_BROADCAST; 241 dst->sin_addr = ip->ip_dst; 242 ifp = ia->ia_ifp; 243 ip->ip_ttl = 1; 244 isbroadcast = 1; 245 } else if (flags & IP_ROUTETOIF) { 246 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 247 (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) { 248 IPSTAT_INC(ips_noroute); 249 error = ENETUNREACH; 250 goto bad; 251 } 252 ifp = ia->ia_ifp; 253 ip->ip_ttl = 1; 254 isbroadcast = in_broadcast(dst->sin_addr, ifp); 255 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 256 imo != NULL && imo->imo_multicast_ifp != NULL) { 257 /* 258 * Bypass the normal routing lookup for multicast 259 * packets if the interface is specified. 260 */ 261 ifp = imo->imo_multicast_ifp; 262 IFP_TO_IA(ifp, ia); 263 isbroadcast = 0; /* fool gcc */ 264 } else { 265 /* 266 * We want to do any cloning requested by the link layer, 267 * as this is probably required in all cases for correct 268 * operation (as it is for ARP). 269 */ 270 if (rte == NULL) { 271 #ifdef RADIX_MPATH 272 rtalloc_mpath_fib(ro, 273 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 274 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 275 #else 276 in_rtalloc_ign(ro, 0, 277 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 278 #endif 279 rte = ro->ro_rt; 280 } 281 if (rte == NULL || 282 rte->rt_ifp == NULL || 283 !RT_LINK_IS_UP(rte->rt_ifp)) { 284 #ifdef IPSEC 285 /* 286 * There is no route for this packet, but it is 287 * possible that a matching SPD entry exists. 288 */ 289 no_route_but_check_spd = 1; 290 mtu = 0; /* Silence GCC warning. */ 291 goto sendit; 292 #endif 293 IPSTAT_INC(ips_noroute); 294 error = EHOSTUNREACH; 295 goto bad; 296 } 297 ia = ifatoia(rte->rt_ifa); 298 ifa_ref(&ia->ia_ifa); 299 ifp = rte->rt_ifp; 300 rte->rt_rmx.rmx_pksent++; 301 if (rte->rt_flags & RTF_GATEWAY) 302 dst = (struct sockaddr_in *)rte->rt_gateway; 303 if (rte->rt_flags & RTF_HOST) 304 isbroadcast = (rte->rt_flags & RTF_BROADCAST); 305 else 306 isbroadcast = in_broadcast(dst->sin_addr, ifp); 307 } 308 /* 309 * Calculate MTU. If we have a route that is up, use that, 310 * otherwise use the interface's MTU. 311 */ 312 if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) { 313 /* 314 * This case can happen if the user changed the MTU 315 * of an interface after enabling IP on it. Because 316 * most netifs don't keep track of routes pointing to 317 * them, there is no way for one to update all its 318 * routes when the MTU is changed. 319 */ 320 if (rte->rt_rmx.rmx_mtu > ifp->if_mtu) 321 rte->rt_rmx.rmx_mtu = ifp->if_mtu; 322 mtu = rte->rt_rmx.rmx_mtu; 323 } else { 324 mtu = ifp->if_mtu; 325 } 326 /* Catch a possible divide by zero later. */ 327 KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p", 328 __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp)); 329 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 330 m->m_flags |= M_MCAST; 331 /* 332 * IP destination address is multicast. Make sure "dst" 333 * still points to the address in "ro". (It may have been 334 * changed to point to a gateway address, above.) 335 */ 336 dst = (struct sockaddr_in *)&ro->ro_dst; 337 /* 338 * See if the caller provided any multicast options 339 */ 340 if (imo != NULL) { 341 ip->ip_ttl = imo->imo_multicast_ttl; 342 if (imo->imo_multicast_vif != -1) 343 ip->ip_src.s_addr = 344 ip_mcast_src ? 345 ip_mcast_src(imo->imo_multicast_vif) : 346 INADDR_ANY; 347 } else 348 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 349 /* 350 * Confirm that the outgoing interface supports multicast. 351 */ 352 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 353 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 354 IPSTAT_INC(ips_noroute); 355 error = ENETUNREACH; 356 goto bad; 357 } 358 } 359 /* 360 * If source address not specified yet, use address 361 * of outgoing interface. 362 */ 363 if (ip->ip_src.s_addr == INADDR_ANY) { 364 /* Interface may have no addresses. */ 365 if (ia != NULL) 366 ip->ip_src = IA_SIN(ia)->sin_addr; 367 } 368 369 if ((imo == NULL && in_mcast_loop) || 370 (imo && imo->imo_multicast_loop)) { 371 /* 372 * Loop back multicast datagram if not expressly 373 * forbidden to do so, even if we are not a member 374 * of the group; ip_input() will filter it later, 375 * thus deferring a hash lookup and mutex acquisition 376 * at the expense of a cheap copy using m_copym(). 377 */ 378 ip_mloopback(ifp, m, dst, hlen); 379 } else { 380 /* 381 * If we are acting as a multicast router, perform 382 * multicast forwarding as if the packet had just 383 * arrived on the interface to which we are about 384 * to send. The multicast forwarding function 385 * recursively calls this function, using the 386 * IP_FORWARDING flag to prevent infinite recursion. 387 * 388 * Multicasts that are looped back by ip_mloopback(), 389 * above, will be forwarded by the ip_input() routine, 390 * if necessary. 391 */ 392 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) { 393 /* 394 * If rsvp daemon is not running, do not 395 * set ip_moptions. This ensures that the packet 396 * is multicast and not just sent down one link 397 * as prescribed by rsvpd. 398 */ 399 if (!V_rsvp_on) 400 imo = NULL; 401 if (ip_mforward && 402 ip_mforward(ip, ifp, m, imo) != 0) { 403 m_freem(m); 404 goto done; 405 } 406 } 407 } 408 409 /* 410 * Multicasts with a time-to-live of zero may be looped- 411 * back, above, but must not be transmitted on a network. 412 * Also, multicasts addressed to the loopback interface 413 * are not sent -- the above call to ip_mloopback() will 414 * loop back a copy. ip_input() will drop the copy if 415 * this host does not belong to the destination group on 416 * the loopback interface. 417 */ 418 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 419 m_freem(m); 420 goto done; 421 } 422 423 goto sendit; 424 } 425 426 /* 427 * If the source address is not specified yet, use the address 428 * of the outoing interface. 429 */ 430 if (ip->ip_src.s_addr == INADDR_ANY) { 431 /* Interface may have no addresses. */ 432 if (ia != NULL) { 433 ip->ip_src = IA_SIN(ia)->sin_addr; 434 } 435 } 436 437 /* 438 * Verify that we have any chance at all of being able to queue the 439 * packet or packet fragments, unless ALTQ is enabled on the given 440 * interface in which case packetdrop should be done by queueing. 441 */ 442 n = ip->ip_len / mtu + 1; /* how many fragments ? */ 443 if ( 444 #ifdef ALTQ 445 (!ALTQ_IS_ENABLED(&ifp->if_snd)) && 446 #endif /* ALTQ */ 447 (ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) { 448 error = ENOBUFS; 449 IPSTAT_INC(ips_odropped); 450 ifp->if_snd.ifq_drops += n; 451 goto bad; 452 } 453 454 /* 455 * Look for broadcast address and 456 * verify user is allowed to send 457 * such a packet. 458 */ 459 if (isbroadcast) { 460 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 461 error = EADDRNOTAVAIL; 462 goto bad; 463 } 464 if ((flags & IP_ALLOWBROADCAST) == 0) { 465 error = EACCES; 466 goto bad; 467 } 468 /* don't allow broadcast messages to be fragmented */ 469 if (ip->ip_len > mtu) { 470 error = EMSGSIZE; 471 goto bad; 472 } 473 m->m_flags |= M_BCAST; 474 } else { 475 m->m_flags &= ~M_BCAST; 476 } 477 478 sendit: 479 #ifdef IPSEC 480 switch(ip_ipsec_output(&m, inp, &flags, &error)) { 481 case 1: 482 goto bad; 483 case -1: 484 goto done; 485 case 0: 486 default: 487 break; /* Continue with packet processing. */ 488 } 489 /* 490 * Check if there was a route for this packet; return error if not. 491 */ 492 if (no_route_but_check_spd) { 493 IPSTAT_INC(ips_noroute); 494 error = EHOSTUNREACH; 495 goto bad; 496 } 497 /* Update variables that are affected by ipsec4_output(). */ 498 ip = mtod(m, struct ip *); 499 hlen = ip->ip_hl << 2; 500 #endif /* IPSEC */ 501 502 /* Jump over all PFIL processing if hooks are not active. */ 503 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 504 goto passout; 505 506 /* Run through list of hooks for output packets. */ 507 odst.s_addr = ip->ip_dst.s_addr; 508 error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 509 if (error != 0 || m == NULL) 510 goto done; 511 512 ip = mtod(m, struct ip *); 513 514 /* See if destination IP address was changed by packet filter. */ 515 if (odst.s_addr != ip->ip_dst.s_addr) { 516 m->m_flags |= M_SKIP_FIREWALL; 517 /* If destination is now ourself drop to ip_input(). */ 518 if (in_localip(ip->ip_dst)) { 519 m->m_flags |= M_FASTFWD_OURS; 520 if (m->m_pkthdr.rcvif == NULL) 521 m->m_pkthdr.rcvif = V_loif; 522 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 523 m->m_pkthdr.csum_flags |= 524 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 525 m->m_pkthdr.csum_data = 0xffff; 526 } 527 m->m_pkthdr.csum_flags |= 528 CSUM_IP_CHECKED | CSUM_IP_VALID; 529 #ifdef SCTP 530 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 531 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 532 #endif 533 error = netisr_queue(NETISR_IP, m); 534 goto done; 535 } else 536 goto again; /* Redo the routing table lookup. */ 537 } 538 539 #ifdef IPFIREWALL_FORWARD 540 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 541 if (m->m_flags & M_FASTFWD_OURS) { 542 if (m->m_pkthdr.rcvif == NULL) 543 m->m_pkthdr.rcvif = V_loif; 544 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 545 m->m_pkthdr.csum_flags |= 546 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 547 m->m_pkthdr.csum_data = 0xffff; 548 } 549 #ifdef SCTP 550 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 551 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 552 #endif 553 m->m_pkthdr.csum_flags |= 554 CSUM_IP_CHECKED | CSUM_IP_VALID; 555 556 error = netisr_queue(NETISR_IP, m); 557 goto done; 558 } 559 /* Or forward to some other address? */ 560 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 561 if (fwd_tag) { 562 dst = (struct sockaddr_in *)&ro->ro_dst; 563 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 564 m->m_flags |= M_SKIP_FIREWALL; 565 m_tag_delete(m, fwd_tag); 566 goto again; 567 } 568 #endif /* IPFIREWALL_FORWARD */ 569 570 passout: 571 /* 127/8 must not appear on wire - RFC1122. */ 572 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 573 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 574 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 575 IPSTAT_INC(ips_badaddr); 576 error = EADDRNOTAVAIL; 577 goto bad; 578 } 579 } 580 581 m->m_pkthdr.csum_flags |= CSUM_IP; 582 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 583 if (sw_csum & CSUM_DELAY_DATA) { 584 in_delayed_cksum(m); 585 sw_csum &= ~CSUM_DELAY_DATA; 586 } 587 #ifdef SCTP 588 if (sw_csum & CSUM_SCTP) { 589 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 590 sw_csum &= ~CSUM_SCTP; 591 } 592 #endif 593 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 594 595 /* 596 * If small enough for interface, or the interface will take 597 * care of the fragmentation for us, we can just send directly. 598 */ 599 if (ip->ip_len <= mtu || 600 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 601 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 602 ip->ip_len = htons(ip->ip_len); 603 ip->ip_off = htons(ip->ip_off); 604 ip->ip_sum = 0; 605 if (sw_csum & CSUM_DELAY_IP) 606 ip->ip_sum = in_cksum(m, hlen); 607 608 /* 609 * Record statistics for this interface address. 610 * With CSUM_TSO the byte/packet count will be slightly 611 * incorrect because we count the IP+TCP headers only 612 * once instead of for every generated packet. 613 */ 614 if (!(flags & IP_FORWARDING) && ia) { 615 if (m->m_pkthdr.csum_flags & CSUM_TSO) 616 ia->ia_ifa.if_opackets += 617 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 618 else 619 ia->ia_ifa.if_opackets++; 620 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 621 } 622 #ifdef MBUF_STRESS_TEST 623 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 624 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 625 #endif 626 /* 627 * Reset layer specific mbuf flags 628 * to avoid confusing lower layers. 629 */ 630 m->m_flags &= ~(M_PROTOFLAGS); 631 error = (*ifp->if_output)(ifp, m, 632 (struct sockaddr *)dst, ro); 633 goto done; 634 } 635 636 /* Balk when DF bit is set or the interface didn't support TSO. */ 637 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 638 error = EMSGSIZE; 639 IPSTAT_INC(ips_cantfrag); 640 goto bad; 641 } 642 643 /* 644 * Too large for interface; fragment if possible. If successful, 645 * on return, m will point to a list of packets to be sent. 646 */ 647 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 648 if (error) 649 goto bad; 650 for (; m; m = m0) { 651 m0 = m->m_nextpkt; 652 m->m_nextpkt = 0; 653 if (error == 0) { 654 /* Record statistics for this interface address. */ 655 if (ia != NULL) { 656 ia->ia_ifa.if_opackets++; 657 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 658 } 659 /* 660 * Reset layer specific mbuf flags 661 * to avoid confusing upper layers. 662 */ 663 m->m_flags &= ~(M_PROTOFLAGS); 664 665 error = (*ifp->if_output)(ifp, m, 666 (struct sockaddr *)dst, ro); 667 } else 668 m_freem(m); 669 } 670 671 if (error == 0) 672 IPSTAT_INC(ips_fragmented); 673 674 done: 675 if (ro == &iproute && ro->ro_rt && !nortfree) { 676 RTFREE(ro->ro_rt); 677 } 678 if (ia != NULL) 679 ifa_free(&ia->ia_ifa); 680 return (error); 681 bad: 682 m_freem(m); 683 goto done; 684 } 685 686 /* 687 * Create a chain of fragments which fit the given mtu. m_frag points to the 688 * mbuf to be fragmented; on return it points to the chain with the fragments. 689 * Return 0 if no error. If error, m_frag may contain a partially built 690 * chain of fragments that should be freed by the caller. 691 * 692 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 693 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 694 */ 695 int 696 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 697 u_long if_hwassist_flags, int sw_csum) 698 { 699 int error = 0; 700 int hlen = ip->ip_hl << 2; 701 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 702 int off; 703 struct mbuf *m0 = *m_frag; /* the original packet */ 704 int firstlen; 705 struct mbuf **mnext; 706 int nfrags; 707 708 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */ 709 IPSTAT_INC(ips_cantfrag); 710 return EMSGSIZE; 711 } 712 713 /* 714 * Must be able to put at least 8 bytes per fragment. 715 */ 716 if (len < 8) 717 return EMSGSIZE; 718 719 /* 720 * If the interface will not calculate checksums on 721 * fragmented packets, then do it here. 722 */ 723 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 724 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 725 in_delayed_cksum(m0); 726 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 727 } 728 #ifdef SCTP 729 if (m0->m_pkthdr.csum_flags & CSUM_SCTP && 730 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 731 sctp_delayed_cksum(m0, hlen); 732 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP; 733 } 734 #endif 735 if (len > PAGE_SIZE) { 736 /* 737 * Fragment large datagrams such that each segment 738 * contains a multiple of PAGE_SIZE amount of data, 739 * plus headers. This enables a receiver to perform 740 * page-flipping zero-copy optimizations. 741 * 742 * XXX When does this help given that sender and receiver 743 * could have different page sizes, and also mtu could 744 * be less than the receiver's page size ? 745 */ 746 int newlen; 747 struct mbuf *m; 748 749 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 750 off += m->m_len; 751 752 /* 753 * firstlen (off - hlen) must be aligned on an 754 * 8-byte boundary 755 */ 756 if (off < hlen) 757 goto smart_frag_failure; 758 off = ((off - hlen) & ~7) + hlen; 759 newlen = (~PAGE_MASK) & mtu; 760 if ((newlen + sizeof (struct ip)) > mtu) { 761 /* we failed, go back the default */ 762 smart_frag_failure: 763 newlen = len; 764 off = hlen + len; 765 } 766 len = newlen; 767 768 } else { 769 off = hlen + len; 770 } 771 772 firstlen = off - hlen; 773 mnext = &m0->m_nextpkt; /* pointer to next packet */ 774 775 /* 776 * Loop through length of segment after first fragment, 777 * make new header and copy data of each part and link onto chain. 778 * Here, m0 is the original packet, m is the fragment being created. 779 * The fragments are linked off the m_nextpkt of the original 780 * packet, which after processing serves as the first fragment. 781 */ 782 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) { 783 struct ip *mhip; /* ip header on the fragment */ 784 struct mbuf *m; 785 int mhlen = sizeof (struct ip); 786 787 MGETHDR(m, M_DONTWAIT, MT_DATA); 788 if (m == NULL) { 789 error = ENOBUFS; 790 IPSTAT_INC(ips_odropped); 791 goto done; 792 } 793 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 794 /* 795 * In the first mbuf, leave room for the link header, then 796 * copy the original IP header including options. The payload 797 * goes into an additional mbuf chain returned by m_copym(). 798 */ 799 m->m_data += max_linkhdr; 800 mhip = mtod(m, struct ip *); 801 *mhip = *ip; 802 if (hlen > sizeof (struct ip)) { 803 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 804 mhip->ip_v = IPVERSION; 805 mhip->ip_hl = mhlen >> 2; 806 } 807 m->m_len = mhlen; 808 /* XXX do we need to add ip->ip_off below ? */ 809 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off; 810 if (off + len >= ip->ip_len) { /* last fragment */ 811 len = ip->ip_len - off; 812 m->m_flags |= M_LASTFRAG; 813 } else 814 mhip->ip_off |= IP_MF; 815 mhip->ip_len = htons((u_short)(len + mhlen)); 816 m->m_next = m_copym(m0, off, len, M_DONTWAIT); 817 if (m->m_next == NULL) { /* copy failed */ 818 m_free(m); 819 error = ENOBUFS; /* ??? */ 820 IPSTAT_INC(ips_odropped); 821 goto done; 822 } 823 m->m_pkthdr.len = mhlen + len; 824 m->m_pkthdr.rcvif = NULL; 825 #ifdef MAC 826 mac_netinet_fragment(m0, m); 827 #endif 828 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 829 mhip->ip_off = htons(mhip->ip_off); 830 mhip->ip_sum = 0; 831 if (sw_csum & CSUM_DELAY_IP) 832 mhip->ip_sum = in_cksum(m, mhlen); 833 *mnext = m; 834 mnext = &m->m_nextpkt; 835 } 836 IPSTAT_ADD(ips_ofragments, nfrags); 837 838 /* set first marker for fragment chain */ 839 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 840 m0->m_pkthdr.csum_data = nfrags; 841 842 /* 843 * Update first fragment by trimming what's been copied out 844 * and updating header. 845 */ 846 m_adj(m0, hlen + firstlen - ip->ip_len); 847 m0->m_pkthdr.len = hlen + firstlen; 848 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 849 ip->ip_off |= IP_MF; 850 ip->ip_off = htons(ip->ip_off); 851 ip->ip_sum = 0; 852 if (sw_csum & CSUM_DELAY_IP) 853 ip->ip_sum = in_cksum(m0, hlen); 854 855 done: 856 *m_frag = m0; 857 return error; 858 } 859 860 void 861 in_delayed_cksum(struct mbuf *m) 862 { 863 struct ip *ip; 864 u_short csum, offset; 865 866 ip = mtod(m, struct ip *); 867 offset = ip->ip_hl << 2 ; 868 csum = in_cksum_skip(m, ip->ip_len, offset); 869 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 870 csum = 0xffff; 871 offset += m->m_pkthdr.csum_data; /* checksum offset */ 872 873 if (offset + sizeof(u_short) > m->m_len) { 874 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 875 m->m_len, offset, ip->ip_p); 876 /* 877 * XXX 878 * this shouldn't happen, but if it does, the 879 * correct behavior may be to insert the checksum 880 * in the appropriate next mbuf in the chain. 881 */ 882 return; 883 } 884 *(u_short *)(m->m_data + offset) = csum; 885 } 886 887 /* 888 * IP socket option processing. 889 */ 890 int 891 ip_ctloutput(struct socket *so, struct sockopt *sopt) 892 { 893 struct inpcb *inp = sotoinpcb(so); 894 int error, optval; 895 896 error = optval = 0; 897 if (sopt->sopt_level != IPPROTO_IP) { 898 if ((sopt->sopt_level == SOL_SOCKET) && 899 (sopt->sopt_name == SO_SETFIB)) { 900 inp->inp_inc.inc_fibnum = so->so_fibnum; 901 return (0); 902 } 903 return (EINVAL); 904 } 905 906 switch (sopt->sopt_dir) { 907 case SOPT_SET: 908 switch (sopt->sopt_name) { 909 case IP_OPTIONS: 910 #ifdef notyet 911 case IP_RETOPTS: 912 #endif 913 { 914 struct mbuf *m; 915 if (sopt->sopt_valsize > MLEN) { 916 error = EMSGSIZE; 917 break; 918 } 919 MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, MT_DATA); 920 if (m == NULL) { 921 error = ENOBUFS; 922 break; 923 } 924 m->m_len = sopt->sopt_valsize; 925 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 926 m->m_len); 927 if (error) { 928 m_free(m); 929 break; 930 } 931 INP_WLOCK(inp); 932 error = ip_pcbopts(inp, sopt->sopt_name, m); 933 INP_WUNLOCK(inp); 934 return (error); 935 } 936 937 case IP_BINDANY: 938 if (sopt->sopt_td != NULL) { 939 error = priv_check(sopt->sopt_td, 940 PRIV_NETINET_BINDANY); 941 if (error) 942 break; 943 } 944 /* FALLTHROUGH */ 945 case IP_TOS: 946 case IP_TTL: 947 case IP_MINTTL: 948 case IP_RECVOPTS: 949 case IP_RECVRETOPTS: 950 case IP_RECVDSTADDR: 951 case IP_RECVTTL: 952 case IP_RECVIF: 953 case IP_FAITH: 954 case IP_ONESBCAST: 955 case IP_DONTFRAG: 956 error = sooptcopyin(sopt, &optval, sizeof optval, 957 sizeof optval); 958 if (error) 959 break; 960 961 switch (sopt->sopt_name) { 962 case IP_TOS: 963 inp->inp_ip_tos = optval; 964 break; 965 966 case IP_TTL: 967 inp->inp_ip_ttl = optval; 968 break; 969 970 case IP_MINTTL: 971 if (optval >= 0 && optval <= MAXTTL) 972 inp->inp_ip_minttl = optval; 973 else 974 error = EINVAL; 975 break; 976 977 #define OPTSET(bit) do { \ 978 INP_WLOCK(inp); \ 979 if (optval) \ 980 inp->inp_flags |= bit; \ 981 else \ 982 inp->inp_flags &= ~bit; \ 983 INP_WUNLOCK(inp); \ 984 } while (0) 985 986 case IP_RECVOPTS: 987 OPTSET(INP_RECVOPTS); 988 break; 989 990 case IP_RECVRETOPTS: 991 OPTSET(INP_RECVRETOPTS); 992 break; 993 994 case IP_RECVDSTADDR: 995 OPTSET(INP_RECVDSTADDR); 996 break; 997 998 case IP_RECVTTL: 999 OPTSET(INP_RECVTTL); 1000 break; 1001 1002 case IP_RECVIF: 1003 OPTSET(INP_RECVIF); 1004 break; 1005 1006 case IP_FAITH: 1007 OPTSET(INP_FAITH); 1008 break; 1009 1010 case IP_ONESBCAST: 1011 OPTSET(INP_ONESBCAST); 1012 break; 1013 case IP_DONTFRAG: 1014 OPTSET(INP_DONTFRAG); 1015 break; 1016 case IP_BINDANY: 1017 OPTSET(INP_BINDANY); 1018 break; 1019 } 1020 break; 1021 #undef OPTSET 1022 1023 /* 1024 * Multicast socket options are processed by the in_mcast 1025 * module. 1026 */ 1027 case IP_MULTICAST_IF: 1028 case IP_MULTICAST_VIF: 1029 case IP_MULTICAST_TTL: 1030 case IP_MULTICAST_LOOP: 1031 case IP_ADD_MEMBERSHIP: 1032 case IP_DROP_MEMBERSHIP: 1033 case IP_ADD_SOURCE_MEMBERSHIP: 1034 case IP_DROP_SOURCE_MEMBERSHIP: 1035 case IP_BLOCK_SOURCE: 1036 case IP_UNBLOCK_SOURCE: 1037 case IP_MSFILTER: 1038 case MCAST_JOIN_GROUP: 1039 case MCAST_LEAVE_GROUP: 1040 case MCAST_JOIN_SOURCE_GROUP: 1041 case MCAST_LEAVE_SOURCE_GROUP: 1042 case MCAST_BLOCK_SOURCE: 1043 case MCAST_UNBLOCK_SOURCE: 1044 error = inp_setmoptions(inp, sopt); 1045 break; 1046 1047 case IP_PORTRANGE: 1048 error = sooptcopyin(sopt, &optval, sizeof optval, 1049 sizeof optval); 1050 if (error) 1051 break; 1052 1053 INP_WLOCK(inp); 1054 switch (optval) { 1055 case IP_PORTRANGE_DEFAULT: 1056 inp->inp_flags &= ~(INP_LOWPORT); 1057 inp->inp_flags &= ~(INP_HIGHPORT); 1058 break; 1059 1060 case IP_PORTRANGE_HIGH: 1061 inp->inp_flags &= ~(INP_LOWPORT); 1062 inp->inp_flags |= INP_HIGHPORT; 1063 break; 1064 1065 case IP_PORTRANGE_LOW: 1066 inp->inp_flags &= ~(INP_HIGHPORT); 1067 inp->inp_flags |= INP_LOWPORT; 1068 break; 1069 1070 default: 1071 error = EINVAL; 1072 break; 1073 } 1074 INP_WUNLOCK(inp); 1075 break; 1076 1077 #ifdef IPSEC 1078 case IP_IPSEC_POLICY: 1079 { 1080 caddr_t req; 1081 struct mbuf *m; 1082 1083 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 1084 break; 1085 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 1086 break; 1087 req = mtod(m, caddr_t); 1088 error = ipsec_set_policy(inp, sopt->sopt_name, req, 1089 m->m_len, (sopt->sopt_td != NULL) ? 1090 sopt->sopt_td->td_ucred : NULL); 1091 m_freem(m); 1092 break; 1093 } 1094 #endif /* IPSEC */ 1095 1096 default: 1097 error = ENOPROTOOPT; 1098 break; 1099 } 1100 break; 1101 1102 case SOPT_GET: 1103 switch (sopt->sopt_name) { 1104 case IP_OPTIONS: 1105 case IP_RETOPTS: 1106 if (inp->inp_options) 1107 error = sooptcopyout(sopt, 1108 mtod(inp->inp_options, 1109 char *), 1110 inp->inp_options->m_len); 1111 else 1112 sopt->sopt_valsize = 0; 1113 break; 1114 1115 case IP_TOS: 1116 case IP_TTL: 1117 case IP_MINTTL: 1118 case IP_RECVOPTS: 1119 case IP_RECVRETOPTS: 1120 case IP_RECVDSTADDR: 1121 case IP_RECVTTL: 1122 case IP_RECVIF: 1123 case IP_PORTRANGE: 1124 case IP_FAITH: 1125 case IP_ONESBCAST: 1126 case IP_DONTFRAG: 1127 case IP_BINDANY: 1128 switch (sopt->sopt_name) { 1129 1130 case IP_TOS: 1131 optval = inp->inp_ip_tos; 1132 break; 1133 1134 case IP_TTL: 1135 optval = inp->inp_ip_ttl; 1136 break; 1137 1138 case IP_MINTTL: 1139 optval = inp->inp_ip_minttl; 1140 break; 1141 1142 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1143 1144 case IP_RECVOPTS: 1145 optval = OPTBIT(INP_RECVOPTS); 1146 break; 1147 1148 case IP_RECVRETOPTS: 1149 optval = OPTBIT(INP_RECVRETOPTS); 1150 break; 1151 1152 case IP_RECVDSTADDR: 1153 optval = OPTBIT(INP_RECVDSTADDR); 1154 break; 1155 1156 case IP_RECVTTL: 1157 optval = OPTBIT(INP_RECVTTL); 1158 break; 1159 1160 case IP_RECVIF: 1161 optval = OPTBIT(INP_RECVIF); 1162 break; 1163 1164 case IP_PORTRANGE: 1165 if (inp->inp_flags & INP_HIGHPORT) 1166 optval = IP_PORTRANGE_HIGH; 1167 else if (inp->inp_flags & INP_LOWPORT) 1168 optval = IP_PORTRANGE_LOW; 1169 else 1170 optval = 0; 1171 break; 1172 1173 case IP_FAITH: 1174 optval = OPTBIT(INP_FAITH); 1175 break; 1176 1177 case IP_ONESBCAST: 1178 optval = OPTBIT(INP_ONESBCAST); 1179 break; 1180 case IP_DONTFRAG: 1181 optval = OPTBIT(INP_DONTFRAG); 1182 break; 1183 case IP_BINDANY: 1184 optval = OPTBIT(INP_BINDANY); 1185 break; 1186 } 1187 error = sooptcopyout(sopt, &optval, sizeof optval); 1188 break; 1189 1190 /* 1191 * Multicast socket options are processed by the in_mcast 1192 * module. 1193 */ 1194 case IP_MULTICAST_IF: 1195 case IP_MULTICAST_VIF: 1196 case IP_MULTICAST_TTL: 1197 case IP_MULTICAST_LOOP: 1198 case IP_MSFILTER: 1199 error = inp_getmoptions(inp, sopt); 1200 break; 1201 1202 #ifdef IPSEC 1203 case IP_IPSEC_POLICY: 1204 { 1205 struct mbuf *m = NULL; 1206 caddr_t req = NULL; 1207 size_t len = 0; 1208 1209 if (m != 0) { 1210 req = mtod(m, caddr_t); 1211 len = m->m_len; 1212 } 1213 error = ipsec_get_policy(sotoinpcb(so), req, len, &m); 1214 if (error == 0) 1215 error = soopt_mcopyout(sopt, m); /* XXX */ 1216 if (error == 0) 1217 m_freem(m); 1218 break; 1219 } 1220 #endif /* IPSEC */ 1221 1222 default: 1223 error = ENOPROTOOPT; 1224 break; 1225 } 1226 break; 1227 } 1228 return (error); 1229 } 1230 1231 /* 1232 * Routine called from ip_output() to loop back a copy of an IP multicast 1233 * packet to the input queue of a specified interface. Note that this 1234 * calls the output routine of the loopback "driver", but with an interface 1235 * pointer that might NOT be a loopback interface -- evil, but easier than 1236 * replicating that code here. 1237 */ 1238 static void 1239 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1240 int hlen) 1241 { 1242 register struct ip *ip; 1243 struct mbuf *copym; 1244 1245 /* 1246 * Make a deep copy of the packet because we're going to 1247 * modify the pack in order to generate checksums. 1248 */ 1249 copym = m_dup(m, M_DONTWAIT); 1250 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1251 copym = m_pullup(copym, hlen); 1252 if (copym != NULL) { 1253 /* If needed, compute the checksum and mark it as valid. */ 1254 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1255 in_delayed_cksum(copym); 1256 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1257 copym->m_pkthdr.csum_flags |= 1258 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1259 copym->m_pkthdr.csum_data = 0xffff; 1260 } 1261 /* 1262 * We don't bother to fragment if the IP length is greater 1263 * than the interface's MTU. Can this possibly matter? 1264 */ 1265 ip = mtod(copym, struct ip *); 1266 ip->ip_len = htons(ip->ip_len); 1267 ip->ip_off = htons(ip->ip_off); 1268 ip->ip_sum = 0; 1269 ip->ip_sum = in_cksum(copym, hlen); 1270 #if 1 /* XXX */ 1271 if (dst->sin_family != AF_INET) { 1272 printf("ip_mloopback: bad address family %d\n", 1273 dst->sin_family); 1274 dst->sin_family = AF_INET; 1275 } 1276 #endif 1277 if_simloop(ifp, copym, dst->sin_family, 0); 1278 } 1279 } 1280