1139823Simp/*- 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 30122702Sandre/* 31122702Sandre * ip_fastforward gets its speed from processing the forwarded packet to 32122702Sandre * completion (if_output on the other side) without any queues or netisr's. 33122702Sandre * The receiving interface DMAs the packet into memory, the upper half of 34122702Sandre * driver calls ip_fastforward, we do our routing table lookup and directly 35148324Skeramida * send it off to the outgoing interface, which DMAs the packet to the 36122702Sandre * network card. The only part of the packet we touch with the CPU is the 37122759Sandre * IP header (unless there are complex firewall rules touching other parts 38122759Sandre * of the packet, but that is up to you). We are essentially limited by bus 39122759Sandre * bandwidth and how fast the network card/driver can set up receives and 40122759Sandre * transmits. 41122702Sandre * 42148324Skeramida * We handle basic errors, IP header errors, checksum errors, 43122702Sandre * destination unreachable, fragmentation and fragmentation needed and 44148324Skeramida * report them via ICMP to the sender. 45122702Sandre * 46122702Sandre * Else if something is not pure IPv4 unicast forwarding we fall back to 47122702Sandre * the normal ip_input processing path. We should only be called from 48122702Sandre * interfaces connected to the outside world. 49122702Sandre * 50122702Sandre * Firewalling is fully supported including divert, ipfw fwd and ipfilter 51122702Sandre * ipnat and address rewrite. 52122702Sandre * 53122702Sandre * IPSEC is not supported if this host is a tunnel broker. IPSEC is 54122702Sandre * supported for connections to/from local host. 55122702Sandre * 56122702Sandre * We try to do the least expensive (in CPU ops) checks and operations 57122702Sandre * first to catch junk with as little overhead as possible. 58122702Sandre * 59148324Skeramida * We take full advantage of hardware support for IP checksum and 60122702Sandre * fragmentation offloading. 61122702Sandre * 62122702Sandre * We don't do ICMP redirect in the fast forwarding path. I have had my own 63122702Sandre * cases where two core routers with Zebra routing suite would send millions 64148324Skeramida * ICMP redirects to connected hosts if the destination router was not the 65148324Skeramida * default gateway. In one case it was filling the routing table of a host 66148324Skeramida * with approximately 300.000 cloned redirect entries until it ran out of 67148324Skeramida * kernel memory. However the networking code proved very robust and it didn't 68148324Skeramida * crash or fail in other ways. 69122702Sandre */ 70122702Sandre 71122702Sandre/* 72122702Sandre * Many thanks to Matt Thomas of NetBSD for basic structure of ip_flow.c which 73122702Sandre * is being followed here. 74122702Sandre */ 75122702Sandre 76172467Ssilby#include <sys/cdefs.h> 77172467Ssilby__FBSDID("$FreeBSD$"); 78172467Ssilby 79122702Sandre#include "opt_ipfw.h" 80122702Sandre#include "opt_ipstealth.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> 97196019Srwatson#include <net/vnet.h> 98122702Sandre 99122702Sandre#include <netinet/in.h> 100122702Sandre#include <netinet/in_systm.h> 101122702Sandre#include <netinet/in_var.h> 102122702Sandre#include <netinet/ip.h> 103122702Sandre#include <netinet/ip_var.h> 104122702Sandre#include <netinet/ip_icmp.h> 105152592Sandre#include <netinet/ip_options.h> 106122702Sandre 107122702Sandre#include <machine/in_cksum.h> 108122702Sandre 109215701Sdimstatic VNET_DEFINE(int, ipfastforward_active); 110195727Srwatson#define V_ipfastforward_active VNET(ipfastforward_active) 111122702Sandre 112195699SrwatsonSYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW, 113195699Srwatson &VNET_NAME(ipfastforward_active), 0, "Enable fast IP forwarding"); 114195699Srwatson 115128872Sandrestatic struct sockaddr_in * 116133497Sandreip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m) 117128872Sandre{ 118128872Sandre struct sockaddr_in *dst; 119128872Sandre struct rtentry *rt; 120128872Sandre 121128872Sandre /* 122128872Sandre * Find route to destination. 123128872Sandre */ 124128872Sandre bzero(ro, sizeof(*ro)); 125128872Sandre dst = (struct sockaddr_in *)&ro->ro_dst; 126128872Sandre dst->sin_family = AF_INET; 127128872Sandre dst->sin_len = sizeof(*dst); 128133497Sandre dst->sin_addr.s_addr = dest.s_addr; 129186119Sqingli in_rtalloc_ign(ro, 0, M_GETFIB(m)); 130128872Sandre 131128872Sandre /* 132128872Sandre * Route there and interface still up? 133128872Sandre */ 134128872Sandre rt = ro->ro_rt; 135128872Sandre if (rt && (rt->rt_flags & RTF_UP) && 136128872Sandre (rt->rt_ifp->if_flags & IFF_UP) && 137148887Srwatson (rt->rt_ifp->if_drv_flags & IFF_DRV_RUNNING)) { 138128872Sandre if (rt->rt_flags & RTF_GATEWAY) 139128872Sandre dst = (struct sockaddr_in *)rt->rt_gateway; 140128872Sandre } else { 141190951Srwatson IPSTAT_INC(ips_noroute); 142190951Srwatson IPSTAT_INC(ips_cantforward); 143128872Sandre if (rt) 144128872Sandre RTFREE(rt); 145145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 146128872Sandre return NULL; 147128872Sandre } 148128872Sandre return dst; 149128872Sandre} 150128872Sandre 151122702Sandre/* 152122702Sandre * Try to forward a packet based on the destination address. 153122702Sandre * This is a fast path optimized for the plain forwarding case. 154196881Spjd * If the packet is handled (and consumed) here then we return NULL; 155196881Spjd * otherwise mbuf is returned and the packet should be delivered 156122702Sandre * to ip_input for full processing. 157122702Sandre */ 158154518Sandrestruct mbuf * 159122702Sandreip_fastforward(struct mbuf *m) 160122702Sandre{ 161122702Sandre struct ip *ip; 162122702Sandre struct mbuf *m0 = NULL; 163122702Sandre struct route ro; 164122702Sandre struct sockaddr_in *dst = NULL; 165128872Sandre struct ifnet *ifp; 166133497Sandre struct in_addr odest, dest; 167128872Sandre u_short sum, ip_len; 168122702Sandre int error = 0; 169133920Sandre int hlen, mtu; 170243586Sae struct m_tag *fwd_tag = NULL; 171122702Sandre 172122702Sandre /* 173122702Sandre * Are we active and forwarding packets? 174122702Sandre */ 175181803Sbz if (!V_ipfastforward_active || !V_ipforwarding) 176154518Sandre return m; 177122702Sandre 178122702Sandre M_ASSERTVALID(m); 179122702Sandre M_ASSERTPKTHDR(m); 180122702Sandre 181191148Skmacy bzero(&ro, sizeof(ro)); 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)) { 191190951Srwatson IPSTAT_INC(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) && 199137302Sandre (m = m_pullup(m, sizeof (struct ip))) == NULL) { 200190951Srwatson IPSTAT_INC(ips_toosmall); 201154518Sandre return NULL; /* mbuf already free'd */ 202122702Sandre } 203122702Sandre 204122702Sandre ip = mtod(m, struct ip *); 205122702Sandre 206122702Sandre /* 207122702Sandre * Is it IPv4? 208122702Sandre */ 209122702Sandre if (ip->ip_v != IPVERSION) { 210190951Srwatson IPSTAT_INC(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 */ 219216192Sbz IPSTAT_INC(ips_badhlen); 220122702Sandre goto drop; 221122702Sandre } 222122702Sandre if (hlen > m->m_len) { 223154518Sandre if ((m = m_pullup(m, hlen)) == NULL) { 224190951Srwatson IPSTAT_INC(ips_badhlen); 225154518Sandre return NULL; /* mbuf already free'd */ 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) { 242190951Srwatson IPSTAT_INC(ips_badsum); 243122702Sandre goto drop; 244122702Sandre } 245136690Sandre 246136690Sandre /* 247148324Skeramida * Remember that we have checked the IP header and found it valid. 248136690Sandre */ 249122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 250122702Sandre 251128872Sandre ip_len = ntohs(ip->ip_len); 252122702Sandre 253122702Sandre /* 254122702Sandre * Is IP length longer than packet we have got? 255122702Sandre */ 256128872Sandre if (m->m_pkthdr.len < ip_len) { 257190951Srwatson IPSTAT_INC(ips_tooshort); 258122702Sandre goto drop; 259122702Sandre } 260122702Sandre 261122702Sandre /* 262122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 263122702Sandre */ 264128872Sandre if (m->m_pkthdr.len > ip_len) { 265122702Sandre if (m->m_len == m->m_pkthdr.len) { 266128872Sandre m->m_len = ip_len; 267128872Sandre m->m_pkthdr.len = ip_len; 268122702Sandre } else 269128872Sandre m_adj(m, ip_len - m->m_pkthdr.len); 270122702Sandre } 271122702Sandre 272122702Sandre /* 273122702Sandre * Is packet from or to 127/8? 274122702Sandre */ 275122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 276122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 277190951Srwatson IPSTAT_INC(ips_badaddr); 278122702Sandre goto drop; 279122702Sandre } 280122702Sandre 281133480Sandre#ifdef ALTQ 282122702Sandre /* 283133480Sandre * Is packet dropped by traffic conditioner? 284133480Sandre */ 285133480Sandre if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 286154518Sandre goto drop; 287133480Sandre#endif 288133480Sandre 289133480Sandre /* 290122702Sandre * Step 2: fallback conditions to normal ip_input path processing 291122702Sandre */ 292122702Sandre 293122702Sandre /* 294122702Sandre * Only IP packets without options 295122702Sandre */ 296129017Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) { 297129017Sandre if (ip_doopts == 1) 298154518Sandre return m; 299129017Sandre else if (ip_doopts == 2) { 300129017Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB, 301145863Sandre 0, 0); 302154518Sandre return NULL; /* mbuf already free'd */ 303129017Sandre } 304129017Sandre /* else ignore IP options and continue */ 305129017Sandre } 306122702Sandre 307122702Sandre /* 308122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 309122702Sandre * no multicast, no INADDR_ANY 310122702Sandre * 311122702Sandre * XXX: Probably some of these checks could be direct drop 312122702Sandre * conditions. However it is not clear whether there are some 313122702Sandre * hacks or obscure behaviours which make it neccessary to 314122702Sandre * let ip_input handle it. We play safe here and let ip_input 315122702Sandre * deal with it until it is proven that we can directly drop it. 316122702Sandre */ 317149369Sandre if ((m->m_flags & (M_BCAST|M_MCAST)) || 318149369Sandre (m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) || 319122702Sandre ntohl(ip->ip_src.s_addr) == (u_long)INADDR_BROADCAST || 320122702Sandre ntohl(ip->ip_dst.s_addr) == (u_long)INADDR_BROADCAST || 321122702Sandre IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 322122702Sandre IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 323166452Sbms IN_LINKLOCAL(ntohl(ip->ip_src.s_addr)) || 324166452Sbms IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) || 325149369Sandre ip->ip_src.s_addr == INADDR_ANY || 326122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 327154518Sandre return m; 328122702Sandre 329122702Sandre /* 330122702Sandre * Is it for a local address on this host? 331122702Sandre */ 332133497Sandre if (in_localip(ip->ip_dst)) 333154518Sandre return m; 334122702Sandre 335190951Srwatson IPSTAT_INC(ips_total); 336122702Sandre 337122702Sandre /* 338122702Sandre * Step 3: incoming packet firewall processing 339122702Sandre */ 340122702Sandre 341128872Sandre /* 342128872Sandre * Convert to host representation 343128872Sandre */ 344128872Sandre ip->ip_len = ntohs(ip->ip_len); 345128872Sandre ip->ip_off = ntohs(ip->ip_off); 346128872Sandre 347133497Sandre odest.s_addr = dest.s_addr = ip->ip_dst.s_addr; 348134383Sandre 349122702Sandre /* 350122702Sandre * Run through list of ipfilter hooks for input packets 351122702Sandre */ 352197952Sjulian if (!PFIL_HOOKED(&V_inet_pfil_hook)) 353134383Sandre goto passin; 354134383Sandre 355197952Sjulian if (pfil_run_hooks( 356197952Sjulian &V_inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN, NULL) || 357122702Sandre m == NULL) 358154518Sandre goto drop; 359122702Sandre 360122702Sandre M_ASSERTVALID(m); 361122702Sandre M_ASSERTPKTHDR(m); 362122702Sandre 363122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 364133497Sandre dest.s_addr = ip->ip_dst.s_addr; 365122702Sandre 366122702Sandre /* 367122702Sandre * Destination address changed? 368122702Sandre */ 369133497Sandre if (odest.s_addr != dest.s_addr) { 370122702Sandre /* 371122702Sandre * Is it now for a local address on this host? 372122702Sandre */ 373133497Sandre if (in_localip(dest)) 374133497Sandre goto forwardlocal; 375122702Sandre /* 376122702Sandre * Go on with new destination address 377122702Sandre */ 378122702Sandre } 379243586Sae 380133920Sandre if (m->m_flags & M_FASTFWD_OURS) { 381133920Sandre /* 382133920Sandre * ipfw changed it for a local address on this host. 383133920Sandre */ 384133920Sandre goto forwardlocal; 385133920Sandre } 386122702Sandre 387134383Sandrepassin: 388122702Sandre /* 389122702Sandre * Step 4: decrement TTL and look up route 390122702Sandre */ 391122702Sandre 392122702Sandre /* 393122702Sandre * Check TTL 394122702Sandre */ 395122702Sandre#ifdef IPSTEALTH 396181803Sbz if (!V_ipstealth) { 397122702Sandre#endif 398122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 399145863Sandre icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0); 400154518Sandre return NULL; /* mbuf already free'd */ 401122702Sandre } 402122702Sandre 403122702Sandre /* 404136690Sandre * Decrement the TTL and incrementally change the IP header checksum. 405136690Sandre * Don't bother doing this with hw checksum offloading, it's faster 406136690Sandre * doing it right here. 407122702Sandre */ 408122702Sandre ip->ip_ttl -= IPTTLDEC; 409122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 410122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 411122702Sandre else 412122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 413122702Sandre#ifdef IPSTEALTH 414122702Sandre } 415122702Sandre#endif 416122702Sandre 417122702Sandre /* 418122702Sandre * Find route to destination. 419122702Sandre */ 420128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 421154518Sandre return NULL; /* icmp unreach already sent */ 422128872Sandre ifp = ro.ro_rt->rt_ifp; 423122702Sandre 424122702Sandre /* 425166507Sbms * Immediately drop blackholed traffic, and directed broadcasts 426166507Sbms * for either the all-ones or all-zero subnet addresses on 427166507Sbms * locally attached networks. 428137179Sbms */ 429166507Sbms if ((ro.ro_rt->rt_flags & (RTF_BLACKHOLE|RTF_BROADCAST)) != 0) 430137179Sbms goto drop; 431137179Sbms 432137179Sbms /* 433122702Sandre * Step 5: outgoing firewall packet processing 434122702Sandre */ 435122702Sandre 436122702Sandre /* 437122702Sandre * Run through list of hooks for output packets. 438122702Sandre */ 439197952Sjulian if (!PFIL_HOOKED(&V_inet_pfil_hook)) 440134383Sandre goto passout; 441134383Sandre 442197952Sjulian if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, NULL) || m == NULL) { 443154518Sandre goto drop; 444122702Sandre } 445122702Sandre 446122702Sandre M_ASSERTVALID(m); 447122702Sandre M_ASSERTPKTHDR(m); 448122702Sandre 449122702Sandre ip = mtod(m, struct ip *); 450133497Sandre dest.s_addr = ip->ip_dst.s_addr; 451122702Sandre 452122702Sandre /* 453122702Sandre * Destination address changed? 454122702Sandre */ 455243586Sae if (m->m_flags & M_IP_NEXTHOP) 456243586Sae fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 457133920Sandre if (odest.s_addr != dest.s_addr || fwd_tag != NULL) { 458122702Sandre /* 459122702Sandre * Is it now for a local address on this host? 460122702Sandre */ 461136690Sandre if (m->m_flags & M_FASTFWD_OURS || in_localip(dest)) { 462122702Sandreforwardlocal: 463133497Sandre /* 464135158Sandre * Return packet for processing by ip_input(). 465135158Sandre * Keep host byte order as expected at ip_input's 466135158Sandre * "ours"-label. 467133497Sandre */ 468135158Sandre m->m_flags |= M_FASTFWD_OURS; 469133497Sandre if (ro.ro_rt) 470133497Sandre RTFREE(ro.ro_rt); 471154518Sandre return m; 472122702Sandre } 473122702Sandre /* 474122702Sandre * Redo route lookup with new destination address 475122702Sandre */ 476133920Sandre if (fwd_tag) { 477161380Sjulian dest.s_addr = ((struct sockaddr_in *) 478157833Sglebius (fwd_tag + 1))->sin_addr.s_addr; 479133920Sandre m_tag_delete(m, fwd_tag); 480243586Sae m->m_flags &= ~M_IP_NEXTHOP; 481133920Sandre } 482122702Sandre RTFREE(ro.ro_rt); 483128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 484154518Sandre return NULL; /* icmp unreach already sent */ 485128872Sandre ifp = ro.ro_rt->rt_ifp; 486122702Sandre } 487122702Sandre 488134383Sandrepassout: 489122702Sandre /* 490122702Sandre * Step 6: send off the packet 491122702Sandre */ 492122702Sandre 493122702Sandre /* 494128872Sandre * Check if route is dampned (when ARP is unable to resolve) 495128872Sandre */ 496128872Sandre if ((ro.ro_rt->rt_flags & RTF_REJECT) && 497167682Sbms (ro.ro_rt->rt_rmx.rmx_expire == 0 || 498167682Sbms time_uptime < ro.ro_rt->rt_rmx.rmx_expire)) { 499145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 500128872Sandre goto consumed; 501128872Sandre } 502128872Sandre 503133480Sandre#ifndef ALTQ 504128872Sandre /* 505128872Sandre * Check if there is enough space in the interface queue 506128872Sandre */ 507128872Sandre if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 508128872Sandre ifp->if_snd.ifq_maxlen) { 509190951Srwatson IPSTAT_INC(ips_odropped); 510128872Sandre /* would send source quench here but that is depreciated */ 511128872Sandre goto drop; 512128872Sandre } 513133480Sandre#endif 514128872Sandre 515128872Sandre /* 516128872Sandre * Check if media link state of interface is not down 517128872Sandre */ 518128872Sandre if (ifp->if_link_state == LINK_STATE_DOWN) { 519145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 520128872Sandre goto consumed; 521128872Sandre } 522128872Sandre 523128872Sandre /* 524148324Skeramida * Check if packet fits MTU or if hardware will fragment for us 525122702Sandre */ 526122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 527122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 528122702Sandre else 529122702Sandre mtu = ifp->if_mtu; 530122702Sandre 531122702Sandre if (ip->ip_len <= mtu || 532122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 533122702Sandre /* 534122702Sandre * Restore packet header fields to original values 535122702Sandre */ 536122702Sandre ip->ip_len = htons(ip->ip_len); 537122702Sandre ip->ip_off = htons(ip->ip_off); 538122702Sandre /* 539122702Sandre * Send off the packet via outgoing interface 540122702Sandre */ 541122702Sandre error = (*ifp->if_output)(ifp, m, 542191148Skmacy (struct sockaddr *)dst, &ro); 543122702Sandre } else { 544122702Sandre /* 545128872Sandre * Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery 546122702Sandre */ 547122702Sandre if (ip->ip_off & IP_DF) { 548190951Srwatson IPSTAT_INC(ips_cantfrag); 549122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 550145863Sandre 0, mtu); 551128872Sandre goto consumed; 552122702Sandre } else { 553122702Sandre /* 554148324Skeramida * We have to fragment the packet 555122702Sandre */ 556122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 557128872Sandre /* 558128872Sandre * ip_fragment expects ip_len and ip_off in host byte 559128872Sandre * order but returns all packets in network byte order 560128872Sandre */ 561122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 562122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 563122702Sandre goto drop; 564122702Sandre } 565122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 566122702Sandre /* 567122702Sandre * Send off the fragments via outgoing interface 568122702Sandre */ 569122702Sandre error = 0; 570122702Sandre do { 571122702Sandre m0 = m->m_nextpkt; 572122702Sandre m->m_nextpkt = NULL; 573122702Sandre 574122702Sandre error = (*ifp->if_output)(ifp, m, 575191148Skmacy (struct sockaddr *)dst, &ro); 576122702Sandre if (error) 577122702Sandre break; 578122702Sandre } while ((m = m0) != NULL); 579122702Sandre if (error) { 580122702Sandre /* Reclaim remaining fragments */ 581144301Sglebius for (m = m0; m; m = m0) { 582122702Sandre m0 = m->m_nextpkt; 583122702Sandre m_freem(m); 584122702Sandre } 585122702Sandre } else 586190951Srwatson IPSTAT_INC(ips_fragmented); 587122702Sandre } 588122702Sandre } 589122702Sandre 590122702Sandre if (error != 0) 591190951Srwatson IPSTAT_INC(ips_odropped); 592122702Sandre else { 593122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 594190951Srwatson IPSTAT_INC(ips_forward); 595190951Srwatson IPSTAT_INC(ips_fastforward); 596122702Sandre } 597128872Sandreconsumed: 598122702Sandre RTFREE(ro.ro_rt); 599154518Sandre return NULL; 600122702Sandredrop: 601122702Sandre if (m) 602122702Sandre m_freem(m); 603128872Sandre if (ro.ro_rt) 604128872Sandre RTFREE(ro.ro_rt); 605154518Sandre return NULL; 606122702Sandre} 607