ip_fastfwd.c revision 133920
1122702Sandre/* 2122702Sandre * Copyright (c) 2003 Andre Oppermann, Internet Business Solutions AG 3122702Sandre * All rights reserved. 4122702Sandre * 5122702Sandre * Redistribution and use in source and binary forms, with or without 6122702Sandre * modification, are permitted provided that the following conditions 7122702Sandre * are met: 8122702Sandre * 1. Redistributions of source code must retain the above copyright 9122702Sandre * notice, this list of conditions and the following disclaimer. 10122702Sandre * 2. Redistributions in binary form must reproduce the above copyright 11122702Sandre * notice, this list of conditions and the following disclaimer in the 12122702Sandre * documentation and/or other materials provided with the distribution. 13122702Sandre * 3. The name of the author may not be used to endorse or promote 14122702Sandre * products derived from this software without specific prior written 15122702Sandre * permission. 16122702Sandre * 17122702Sandre * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18122702Sandre * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19122702Sandre * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20122702Sandre * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21122702Sandre * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22122702Sandre * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23122702Sandre * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24122702Sandre * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25122702Sandre * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26122702Sandre * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27122702Sandre * SUCH DAMAGE. 28122702Sandre * 29122702Sandre * $FreeBSD: head/sys/netinet/ip_fastfwd.c 133920 2004-08-17 22:05:54Z andre $ 30122702Sandre */ 31122702Sandre 32122702Sandre/* 33122702Sandre * ip_fastforward gets its speed from processing the forwarded packet to 34122702Sandre * completion (if_output on the other side) without any queues or netisr's. 35122702Sandre * The receiving interface DMAs the packet into memory, the upper half of 36122702Sandre * driver calls ip_fastforward, we do our routing table lookup and directly 37122702Sandre * send it off to the outgoing interface which DMAs the packet to the 38122702Sandre * network card. The only part of the packet we touch with the CPU is the 39122759Sandre * IP header (unless there are complex firewall rules touching other parts 40122759Sandre * of the packet, but that is up to you). We are essentially limited by bus 41122759Sandre * bandwidth and how fast the network card/driver can set up receives and 42122759Sandre * transmits. 43122702Sandre * 44122702Sandre * We handle basic errors, ip header errors, checksum errors, 45122702Sandre * destination unreachable, fragmentation and fragmentation needed and 46122702Sandre * report them via icmp to the sender. 47122702Sandre * 48122702Sandre * Else if something is not pure IPv4 unicast forwarding we fall back to 49122702Sandre * the normal ip_input processing path. We should only be called from 50122702Sandre * interfaces connected to the outside world. 51122702Sandre * 52122702Sandre * Firewalling is fully supported including divert, ipfw fwd and ipfilter 53122702Sandre * ipnat and address rewrite. 54122702Sandre * 55122702Sandre * IPSEC is not supported if this host is a tunnel broker. IPSEC is 56122702Sandre * supported for connections to/from local host. 57122702Sandre * 58122702Sandre * We try to do the least expensive (in CPU ops) checks and operations 59122702Sandre * first to catch junk with as little overhead as possible. 60122702Sandre * 61122702Sandre * We take full advantage of hardware support for ip checksum and 62122702Sandre * fragmentation offloading. 63122702Sandre * 64122702Sandre * We don't do ICMP redirect in the fast forwarding path. I have had my own 65122702Sandre * cases where two core routers with Zebra routing suite would send millions 66122702Sandre * ICMP redirects to connected hosts if the router to dest was not the default 67122702Sandre * gateway. In one case it was filling the routing table of a host with close 68122702Sandre * 300'000 cloned redirect entries until it ran out of kernel memory. However 69122702Sandre * the networking code proved very robust and it didn't crash or went ill 70122702Sandre * otherwise. 71122702Sandre */ 72122702Sandre 73122702Sandre/* 74122702Sandre * Many thanks to Matt Thomas of NetBSD for basic structure of ip_flow.c which 75122702Sandre * is being followed here. 76122702Sandre */ 77122702Sandre 78122702Sandre#include "opt_ipfw.h" 79122702Sandre#include "opt_ipstealth.h" 80122702Sandre#include "opt_pfil_hooks.h" 81122702Sandre 82122702Sandre#include <sys/param.h> 83122702Sandre#include <sys/systm.h> 84122702Sandre#include <sys/kernel.h> 85122702Sandre#include <sys/malloc.h> 86122702Sandre#include <sys/mbuf.h> 87122702Sandre#include <sys/protosw.h> 88122702Sandre#include <sys/socket.h> 89122702Sandre#include <sys/sysctl.h> 90122702Sandre 91122702Sandre#include <net/pfil.h> 92122702Sandre#include <net/if.h> 93122702Sandre#include <net/if_types.h> 94122702Sandre#include <net/if_var.h> 95122702Sandre#include <net/if_dl.h> 96122702Sandre#include <net/route.h> 97122702Sandre 98122702Sandre#include <netinet/in.h> 99122702Sandre#include <netinet/in_systm.h> 100122702Sandre#include <netinet/in_var.h> 101122702Sandre#include <netinet/ip.h> 102122702Sandre#include <netinet/ip_var.h> 103122702Sandre#include <netinet/ip_icmp.h> 104122702Sandre 105122702Sandre#include <machine/in_cksum.h> 106122702Sandre 107122702Sandrestatic int ipfastforward_active = 0; 108122702SandreSYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW, 109122702Sandre &ipfastforward_active, 0, "Enable fast IP forwarding"); 110122702Sandre 111128872Sandrestatic struct sockaddr_in * 112133497Sandreip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m) 113128872Sandre{ 114128872Sandre struct sockaddr_in *dst; 115128872Sandre struct rtentry *rt; 116128872Sandre 117128872Sandre /* 118128872Sandre * Find route to destination. 119128872Sandre */ 120128872Sandre bzero(ro, sizeof(*ro)); 121128872Sandre dst = (struct sockaddr_in *)&ro->ro_dst; 122128872Sandre dst->sin_family = AF_INET; 123128872Sandre dst->sin_len = sizeof(*dst); 124133497Sandre dst->sin_addr.s_addr = dest.s_addr; 125128872Sandre rtalloc_ign(ro, RTF_CLONING); 126128872Sandre 127128872Sandre /* 128128872Sandre * Route there and interface still up? 129128872Sandre */ 130128872Sandre rt = ro->ro_rt; 131128872Sandre if (rt && (rt->rt_flags & RTF_UP) && 132128872Sandre (rt->rt_ifp->if_flags & IFF_UP) && 133128872Sandre (rt->rt_ifp->if_flags & IFF_RUNNING)) { 134128872Sandre if (rt->rt_flags & RTF_GATEWAY) 135128872Sandre dst = (struct sockaddr_in *)rt->rt_gateway; 136128872Sandre } else { 137128872Sandre ipstat.ips_noroute++; 138128872Sandre ipstat.ips_cantforward++; 139128872Sandre if (rt) 140128872Sandre RTFREE(rt); 141128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 142128872Sandre return NULL; 143128872Sandre } 144128872Sandre return dst; 145128872Sandre} 146128872Sandre 147122702Sandre/* 148122702Sandre * Try to forward a packet based on the destination address. 149122702Sandre * This is a fast path optimized for the plain forwarding case. 150122702Sandre * If the packet is handled (and consumed) here then we return 1; 151122702Sandre * otherwise 0 is returned and the packet should be delivered 152122702Sandre * to ip_input for full processing. 153122702Sandre */ 154122702Sandreint 155122702Sandreip_fastforward(struct mbuf *m) 156122702Sandre{ 157122702Sandre struct ip *ip; 158122702Sandre struct mbuf *m0 = NULL; 159122702Sandre struct route ro; 160122702Sandre struct sockaddr_in *dst = NULL; 161122702Sandre struct in_ifaddr *ia = NULL; 162122702Sandre struct ifaddr *ifa = NULL; 163128872Sandre struct ifnet *ifp; 164133497Sandre struct in_addr odest, dest; 165128872Sandre u_short sum, ip_len; 166122702Sandre int error = 0; 167133920Sandre int hlen, mtu; 168133920Sandre#ifdef IPFIREWALL_FORWARD 169133920Sandre struct m_tag *fwd_tag; 170133920Sandre#endif 171122702Sandre 172122702Sandre /* 173122702Sandre * Are we active and forwarding packets? 174122702Sandre */ 175122702Sandre if (!ipfastforward_active || !ipforwarding) 176122702Sandre return 0; 177122702Sandre 178122702Sandre M_ASSERTVALID(m); 179122702Sandre M_ASSERTPKTHDR(m); 180122702Sandre 181128872Sandre ro.ro_rt = NULL; 182128872Sandre 183122702Sandre /* 184122702Sandre * Step 1: check for packet drop conditions (and sanity checks) 185122702Sandre */ 186122702Sandre 187122702Sandre /* 188122702Sandre * Is entire packet big enough? 189122702Sandre */ 190122702Sandre if (m->m_pkthdr.len < sizeof(struct ip)) { 191122702Sandre ipstat.ips_tooshort++; 192122702Sandre goto drop; 193122702Sandre } 194122702Sandre 195122702Sandre /* 196122702Sandre * Is first mbuf large enough for ip header and is header present? 197122702Sandre */ 198122702Sandre if (m->m_len < sizeof (struct ip) && 199122702Sandre (m = m_pullup(m, sizeof (struct ip))) == 0) { 200122702Sandre ipstat.ips_toosmall++; 201122702Sandre goto drop; 202122702Sandre } 203122702Sandre 204122702Sandre ip = mtod(m, struct ip *); 205122702Sandre 206122702Sandre /* 207122702Sandre * Is it IPv4? 208122702Sandre */ 209122702Sandre if (ip->ip_v != IPVERSION) { 210122702Sandre ipstat.ips_badvers++; 211122702Sandre goto drop; 212122702Sandre } 213122702Sandre 214122702Sandre /* 215122702Sandre * Is IP header length correct and is it in first mbuf? 216122702Sandre */ 217122702Sandre hlen = ip->ip_hl << 2; 218122702Sandre if (hlen < sizeof(struct ip)) { /* minimum header length */ 219122702Sandre ipstat.ips_badlen++; 220122702Sandre goto drop; 221122702Sandre } 222122702Sandre if (hlen > m->m_len) { 223122702Sandre if ((m = m_pullup(m, hlen)) == 0) { 224122702Sandre ipstat.ips_badhlen++; 225122702Sandre goto drop; 226122702Sandre } 227122702Sandre ip = mtod(m, struct ip *); 228122702Sandre } 229122702Sandre 230122702Sandre /* 231122702Sandre * Checksum correct? 232122702Sandre */ 233122702Sandre if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) 234122702Sandre sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 235122702Sandre else { 236122702Sandre if (hlen == sizeof(struct ip)) 237122702Sandre sum = in_cksum_hdr(ip); 238122702Sandre else 239122702Sandre sum = in_cksum(m, hlen); 240122702Sandre } 241122702Sandre if (sum) { 242122702Sandre ipstat.ips_badsum++; 243122702Sandre goto drop; 244122702Sandre } 245122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 246122702Sandre 247128872Sandre ip_len = ntohs(ip->ip_len); 248122702Sandre 249122702Sandre /* 250122702Sandre * Is IP length longer than packet we have got? 251122702Sandre */ 252128872Sandre if (m->m_pkthdr.len < ip_len) { 253122702Sandre ipstat.ips_tooshort++; 254122702Sandre goto drop; 255122702Sandre } 256122702Sandre 257122702Sandre /* 258122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 259122702Sandre */ 260128872Sandre if (m->m_pkthdr.len > ip_len) { 261122702Sandre if (m->m_len == m->m_pkthdr.len) { 262128872Sandre m->m_len = ip_len; 263128872Sandre m->m_pkthdr.len = ip_len; 264122702Sandre } else 265128872Sandre m_adj(m, ip_len - m->m_pkthdr.len); 266122702Sandre } 267122702Sandre 268122702Sandre /* 269122702Sandre * Is packet from or to 127/8? 270122702Sandre */ 271122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 272122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 273122702Sandre ipstat.ips_badaddr++; 274122702Sandre goto drop; 275122702Sandre } 276122702Sandre 277133480Sandre#ifdef ALTQ 278122702Sandre /* 279133480Sandre * Is packet dropped by traffic conditioner? 280133480Sandre */ 281133480Sandre if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 282133480Sandre return 1; 283133480Sandre#endif 284133480Sandre 285133480Sandre /* 286122702Sandre * Step 2: fallback conditions to normal ip_input path processing 287122702Sandre */ 288122702Sandre 289122702Sandre /* 290122702Sandre * Only IP packets without options 291122702Sandre */ 292129017Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) { 293129017Sandre if (ip_doopts == 1) 294129017Sandre return 0; 295129017Sandre else if (ip_doopts == 2) { 296129017Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB, 297129017Sandre 0, NULL); 298129017Sandre return 1; 299129017Sandre } 300129017Sandre /* else ignore IP options and continue */ 301129017Sandre } 302122702Sandre 303122702Sandre /* 304122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 305122702Sandre * no multicast, no INADDR_ANY 306122702Sandre * 307122702Sandre * XXX: Probably some of these checks could be direct drop 308122702Sandre * conditions. However it is not clear whether there are some 309122702Sandre * hacks or obscure behaviours which make it neccessary to 310122702Sandre * let ip_input handle it. We play safe here and let ip_input 311122702Sandre * deal with it until it is proven that we can directly drop it. 312122702Sandre */ 313122702Sandre if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) || 314122702Sandre ntohl(ip->ip_src.s_addr) == (u_long)INADDR_BROADCAST || 315122702Sandre ntohl(ip->ip_dst.s_addr) == (u_long)INADDR_BROADCAST || 316122702Sandre IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 317122702Sandre IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 318122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 319128872Sandre return 0; 320122702Sandre 321122702Sandre /* 322122702Sandre * Is it for a local address on this host? 323122702Sandre */ 324133497Sandre if (in_localip(ip->ip_dst)) 325133497Sandre return 0; 326122702Sandre 327122702Sandre /* 328122702Sandre * Or is it for a local IP broadcast address on this host? 329122702Sandre */ 330133482Sandre if ((m->m_flags & M_BCAST) && 331133482Sandre (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 332122702Sandre TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 333122702Sandre if (ifa->ifa_addr->sa_family != AF_INET) 334122702Sandre continue; 335122702Sandre ia = ifatoia(ifa); 336122702Sandre if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 337128872Sandre return 0; 338122702Sandre if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 339122702Sandre ip->ip_dst.s_addr) 340128872Sandre return 0; 341122702Sandre } 342122702Sandre } 343122702Sandre ipstat.ips_total++; 344122702Sandre 345122702Sandre /* 346122702Sandre * Step 3: incoming packet firewall processing 347122702Sandre */ 348122702Sandre 349128872Sandre /* 350128872Sandre * Convert to host representation 351128872Sandre */ 352128872Sandre ip->ip_len = ntohs(ip->ip_len); 353128872Sandre ip->ip_off = ntohs(ip->ip_off); 354128872Sandre 355133497Sandre odest.s_addr = dest.s_addr = ip->ip_dst.s_addr; 356122702Sandre#ifdef PFIL_HOOKS 357122702Sandre /* 358122702Sandre * Run through list of ipfilter hooks for input packets 359122702Sandre */ 360122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN) || 361122702Sandre m == NULL) 362122702Sandre return 1; 363122702Sandre 364122702Sandre M_ASSERTVALID(m); 365122702Sandre M_ASSERTPKTHDR(m); 366122702Sandre 367122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 368133497Sandre dest.s_addr = ip->ip_dst.s_addr; 369122702Sandre 370122702Sandre /* 371122702Sandre * Destination address changed? 372122702Sandre */ 373133497Sandre if (odest.s_addr != dest.s_addr) { 374122702Sandre /* 375122702Sandre * Is it now for a local address on this host? 376122702Sandre */ 377133497Sandre if (in_localip(dest)) 378133497Sandre goto forwardlocal; 379122702Sandre /* 380122702Sandre * Go on with new destination address 381122702Sandre */ 382122702Sandre } 383133920Sandre#ifdef IPFIREWALL_FORWARD 384133920Sandre if (m->m_flags & M_FASTFWD_OURS) { 385133920Sandre /* 386133920Sandre * ipfw changed it for a local address on this host. 387133920Sandre */ 388133920Sandre goto forwardlocal; 389133920Sandre } 390133920Sandre#endif /* IPFIREWALL_FORWARD */ 391133920Sandre#endif /* PFIL_HOOKS */ 392122702Sandre 393122702Sandre /* 394122702Sandre * Step 4: decrement TTL and look up route 395122702Sandre */ 396122702Sandre 397122702Sandre /* 398122702Sandre * Check TTL 399122702Sandre */ 400122702Sandre#ifdef IPSTEALTH 401122702Sandre if (!ipstealth) { 402122702Sandre#endif 403122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 404123740Speter icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, NULL); 405122702Sandre return 1; 406122702Sandre } 407122702Sandre 408122702Sandre /* 409122702Sandre * Decrement the TTL and incrementally change the checksum. 410122702Sandre * Don't bother doing this with hw checksum offloading. 411122702Sandre */ 412122702Sandre ip->ip_ttl -= IPTTLDEC; 413122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 414122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 415122702Sandre else 416122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 417122702Sandre#ifdef IPSTEALTH 418122702Sandre } 419122702Sandre#endif 420122702Sandre 421122702Sandre /* 422122702Sandre * Find route to destination. 423122702Sandre */ 424128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 425128872Sandre return 1; /* icmp unreach already sent */ 426128872Sandre ifp = ro.ro_rt->rt_ifp; 427122702Sandre 428122702Sandre /* 429122702Sandre * Step 5: outgoing firewall packet processing 430122702Sandre */ 431122702Sandre 432122702Sandre#ifdef PFIL_HOOKS 433122702Sandre /* 434122702Sandre * Run through list of hooks for output packets. 435122702Sandre */ 436122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT) || m == NULL) { 437128872Sandre goto consumed; 438122702Sandre } 439122702Sandre 440122702Sandre M_ASSERTVALID(m); 441122702Sandre M_ASSERTPKTHDR(m); 442122702Sandre 443122702Sandre ip = mtod(m, struct ip *); 444133497Sandre dest.s_addr = ip->ip_dst.s_addr; 445122702Sandre 446122702Sandre /* 447122702Sandre * Destination address changed? 448122702Sandre */ 449133920Sandre#ifndef IPFIREWALL_FORWARD 450133497Sandre if (odest.s_addr != dest.s_addr) { 451133920Sandre#else 452133920Sandre fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 453133920Sandre if (odest.s_addr != dest.s_addr || fwd_tag != NULL) { 454133920Sandre#endif /* IPFIREWALL_FORWARD */ 455122702Sandre /* 456122702Sandre * Is it now for a local address on this host? 457122702Sandre */ 458133920Sandre#ifndef IPFIREWALL_FORWARD 459133497Sandre if (in_localip(dest)) { 460133920Sandre#else 461133920Sandre if (in_localip(dest) || m->m_flags & M_FASTFWD_OURS) { 462133920Sandre#endif /* IPFIREWALL_FORWARD */ 463122702Sandreforwardlocal: 464133497Sandre /* for ip_input */ 465133497Sandre m->m_flags |= M_FASTFWD_OURS; 466133497Sandre ip->ip_len = htons(ip->ip_len); 467133497Sandre ip->ip_off = htons(ip->ip_off); 468122702Sandre 469133497Sandre /* 470133920Sandre * Return packet for processing by ip_input() 471133497Sandre */ 472133497Sandre if (ro.ro_rt) 473133497Sandre RTFREE(ro.ro_rt); 474133497Sandre return 0; 475122702Sandre } 476122702Sandre /* 477122702Sandre * Redo route lookup with new destination address 478122702Sandre */ 479133920Sandre#ifdef IPFIREWALL_FORWARD 480133920Sandre if (fwd_tag) { 481133920Sandre if (!in_localip(ip->ip_src) && !in_localaddr(ip->ip_dst)) 482133920Sandre dest.s_addr = ((struct sockaddr_in *)(fwd_tag+1))->sin_addr.s_addr; 483133920Sandre //bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 484133920Sandre m_tag_delete(m, fwd_tag); 485133920Sandre } 486133920Sandre#endif /* IPFIREWALL_FORWARD */ 487122702Sandre RTFREE(ro.ro_rt); 488128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 489128872Sandre return 1; /* icmp unreach already sent */ 490128872Sandre ifp = ro.ro_rt->rt_ifp; 491122702Sandre } 492133920Sandre#endif /* PFIL_HOOKS */ 493122702Sandre 494122702Sandre /* 495122702Sandre * Step 6: send off the packet 496122702Sandre */ 497122702Sandre 498122702Sandre /* 499128872Sandre * Check if route is dampned (when ARP is unable to resolve) 500128872Sandre */ 501128872Sandre if ((ro.ro_rt->rt_flags & RTF_REJECT) && 502128872Sandre ro.ro_rt->rt_rmx.rmx_expire >= time_second) { 503128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 504128872Sandre goto consumed; 505128872Sandre } 506128872Sandre 507133480Sandre#ifndef ALTQ 508128872Sandre /* 509128872Sandre * Check if there is enough space in the interface queue 510128872Sandre */ 511128872Sandre if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 512128872Sandre ifp->if_snd.ifq_maxlen) { 513128872Sandre ipstat.ips_odropped++; 514128872Sandre /* would send source quench here but that is depreciated */ 515128872Sandre goto drop; 516128872Sandre } 517133480Sandre#endif 518128872Sandre 519128872Sandre /* 520128872Sandre * Check if media link state of interface is not down 521128872Sandre */ 522128872Sandre if (ifp->if_link_state == LINK_STATE_DOWN) { 523128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 524128872Sandre goto consumed; 525128872Sandre } 526128872Sandre 527128872Sandre /* 528122702Sandre * Check if packet fits MTU or if hardware will fragement for us 529122702Sandre */ 530122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 531122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 532122702Sandre else 533122702Sandre mtu = ifp->if_mtu; 534122702Sandre 535122702Sandre if (ip->ip_len <= mtu || 536122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 537122702Sandre /* 538122702Sandre * Restore packet header fields to original values 539122702Sandre */ 540122702Sandre ip->ip_len = htons(ip->ip_len); 541122702Sandre ip->ip_off = htons(ip->ip_off); 542122702Sandre /* 543122702Sandre * Send off the packet via outgoing interface 544122702Sandre */ 545122702Sandre error = (*ifp->if_output)(ifp, m, 546122702Sandre (struct sockaddr *)dst, ro.ro_rt); 547122702Sandre } else { 548122702Sandre /* 549128872Sandre * Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery 550122702Sandre */ 551122702Sandre if (ip->ip_off & IP_DF) { 552128872Sandre ipstat.ips_cantfrag++; 553122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 554123740Speter 0, ifp); 555128872Sandre goto consumed; 556122702Sandre } else { 557122702Sandre /* 558122702Sandre * We have to fragement the packet 559122702Sandre */ 560122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 561128872Sandre /* 562128872Sandre * ip_fragment expects ip_len and ip_off in host byte 563128872Sandre * order but returns all packets in network byte order 564128872Sandre */ 565122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 566122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 567122702Sandre goto drop; 568122702Sandre } 569122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 570122702Sandre /* 571122702Sandre * Send off the fragments via outgoing interface 572122702Sandre */ 573122702Sandre error = 0; 574122702Sandre do { 575122702Sandre m0 = m->m_nextpkt; 576122702Sandre m->m_nextpkt = NULL; 577122702Sandre 578122702Sandre error = (*ifp->if_output)(ifp, m, 579122702Sandre (struct sockaddr *)dst, ro.ro_rt); 580122702Sandre if (error) 581122702Sandre break; 582122702Sandre } while ((m = m0) != NULL); 583122702Sandre if (error) { 584122702Sandre /* Reclaim remaining fragments */ 585122702Sandre for (; m; m = m0) { 586122702Sandre m0 = m->m_nextpkt; 587122702Sandre m->m_nextpkt = NULL; 588122702Sandre m_freem(m); 589122702Sandre } 590122702Sandre } else 591122702Sandre ipstat.ips_fragmented++; 592122702Sandre } 593122702Sandre } 594122702Sandre 595122702Sandre if (error != 0) 596122702Sandre ipstat.ips_odropped++; 597122702Sandre else { 598122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 599122702Sandre ipstat.ips_forward++; 600122702Sandre ipstat.ips_fastforward++; 601122702Sandre } 602128872Sandreconsumed: 603122702Sandre RTFREE(ro.ro_rt); 604122702Sandre return 1; 605122702Sandredrop: 606122702Sandre if (m) 607122702Sandre m_freem(m); 608128872Sandre if (ro.ro_rt) 609128872Sandre RTFREE(ro.ro_rt); 610122702Sandre return 1; 611122702Sandre} 612