ip_fastfwd.c revision 122759
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 122759 2003-11-15 17:03:37Z 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_ipdn.h" 80122702Sandre#include "opt_ipdivert.h" 81122702Sandre#include "opt_ipfilter.h" 82122702Sandre#include "opt_ipstealth.h" 83122702Sandre#include "opt_mac.h" 84122702Sandre#include "opt_pfil_hooks.h" 85122702Sandre 86122702Sandre#include <sys/param.h> 87122702Sandre#include <sys/systm.h> 88122702Sandre#include <sys/kernel.h> 89122702Sandre#include <sys/mac.h> 90122702Sandre#include <sys/malloc.h> 91122702Sandre#include <sys/mbuf.h> 92122702Sandre#include <sys/protosw.h> 93122702Sandre#include <sys/socket.h> 94122702Sandre#include <sys/sysctl.h> 95122702Sandre 96122702Sandre#include <net/pfil.h> 97122702Sandre#include <net/if.h> 98122702Sandre#include <net/if_types.h> 99122702Sandre#include <net/if_var.h> 100122702Sandre#include <net/if_dl.h> 101122702Sandre#include <net/route.h> 102122702Sandre 103122702Sandre#include <netinet/in.h> 104122702Sandre#include <netinet/in_systm.h> 105122702Sandre#include <netinet/in_var.h> 106122702Sandre#include <netinet/ip.h> 107122702Sandre#include <netinet/ip_var.h> 108122702Sandre#include <netinet/ip_icmp.h> 109122702Sandre 110122702Sandre#include <machine/in_cksum.h> 111122702Sandre 112122702Sandre#include <netinet/ip_fw.h> 113122702Sandre#include <netinet/ip_dummynet.h> 114122702Sandre 115122702Sandrestatic int ipfastforward_active = 0; 116122702SandreSYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW, 117122702Sandre &ipfastforward_active, 0, "Enable fast IP forwarding"); 118122702Sandre 119122702Sandre/* 120122702Sandre * Try to forward a packet based on the destination address. 121122702Sandre * This is a fast path optimized for the plain forwarding case. 122122702Sandre * If the packet is handled (and consumed) here then we return 1; 123122702Sandre * otherwise 0 is returned and the packet should be delivered 124122702Sandre * to ip_input for full processing. 125122702Sandre */ 126122702Sandreint 127122702Sandreip_fastforward(struct mbuf *m) 128122702Sandre{ 129122702Sandre struct ip *ip; 130122702Sandre struct mbuf *m0 = NULL; 131122702Sandre#ifdef IPDIVERT 132122702Sandre struct ip *tip; 133122702Sandre struct mbuf *teem = NULL; 134122702Sandre#endif 135122702Sandre struct mbuf *tag = NULL; 136122702Sandre struct route ro; 137122702Sandre struct sockaddr_in *dst = NULL; 138122702Sandre struct in_ifaddr *ia = NULL; 139122702Sandre struct ifaddr *ifa = NULL; 140122702Sandre struct ifnet *ifp = NULL; 141122702Sandre struct ip_fw_args args; 142122702Sandre in_addr_t odest, dest; 143122702Sandre u_short sum; 144122702Sandre int error = 0; 145122702Sandre int hlen, ipfw, mtu; 146122702Sandre 147122702Sandre /* 148122702Sandre * Are we active and forwarding packets? 149122702Sandre */ 150122702Sandre if (!ipfastforward_active || !ipforwarding) 151122702Sandre return 0; 152122702Sandre 153122702Sandre /* 154122702Sandre * If there is any MT_TAG we fall back to ip_input because we can't 155122702Sandre * handle TAGs here. Should never happen as we get directly called 156122702Sandre * from the if_output routines. 157122702Sandre */ 158122702Sandre if (m->m_type == MT_TAG) { 159122702Sandre KASSERT(0, ("%s: packet with MT_TAG not expected", __func__)); 160122702Sandre return 0; 161122702Sandre } 162122702Sandre 163122702Sandre M_ASSERTVALID(m); 164122702Sandre M_ASSERTPKTHDR(m); 165122702Sandre 166122702Sandre /* 167122702Sandre * Step 1: check for packet drop conditions (and sanity checks) 168122702Sandre */ 169122702Sandre 170122702Sandre /* 171122702Sandre * Is entire packet big enough? 172122702Sandre */ 173122702Sandre if (m->m_pkthdr.len < sizeof(struct ip)) { 174122702Sandre ipstat.ips_tooshort++; 175122702Sandre goto drop; 176122702Sandre } 177122702Sandre 178122702Sandre /* 179122702Sandre * Is first mbuf large enough for ip header and is header present? 180122702Sandre */ 181122702Sandre if (m->m_len < sizeof (struct ip) && 182122702Sandre (m = m_pullup(m, sizeof (struct ip))) == 0) { 183122702Sandre ipstat.ips_toosmall++; 184122702Sandre goto drop; 185122702Sandre } 186122702Sandre 187122702Sandre ip = mtod(m, struct ip *); 188122702Sandre 189122702Sandre /* 190122702Sandre * Is it IPv4? 191122702Sandre */ 192122702Sandre if (ip->ip_v != IPVERSION) { 193122702Sandre ipstat.ips_badvers++; 194122702Sandre goto drop; 195122702Sandre } 196122702Sandre 197122702Sandre /* 198122702Sandre * Is IP header length correct and is it in first mbuf? 199122702Sandre */ 200122702Sandre hlen = ip->ip_hl << 2; 201122702Sandre if (hlen < sizeof(struct ip)) { /* minimum header length */ 202122702Sandre ipstat.ips_badlen++; 203122702Sandre goto drop; 204122702Sandre } 205122702Sandre if (hlen > m->m_len) { 206122702Sandre if ((m = m_pullup(m, hlen)) == 0) { 207122702Sandre ipstat.ips_badhlen++; 208122702Sandre goto drop; 209122702Sandre } 210122702Sandre ip = mtod(m, struct ip *); 211122702Sandre } 212122702Sandre 213122702Sandre /* 214122702Sandre * Checksum correct? 215122702Sandre */ 216122702Sandre if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) 217122702Sandre sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 218122702Sandre else { 219122702Sandre if (hlen == sizeof(struct ip)) 220122702Sandre sum = in_cksum_hdr(ip); 221122702Sandre else 222122702Sandre sum = in_cksum(m, hlen); 223122702Sandre } 224122702Sandre if (sum) { 225122702Sandre ipstat.ips_badsum++; 226122702Sandre goto drop; 227122702Sandre } 228122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 229122702Sandre 230122702Sandre /* 231122702Sandre * Convert to host representation 232122702Sandre */ 233122702Sandre ip->ip_len = ntohs(ip->ip_len); 234122702Sandre ip->ip_off = ntohs(ip->ip_off); 235122702Sandre 236122702Sandre /* 237122702Sandre * Is IP length longer than packet we have got? 238122702Sandre */ 239122702Sandre if (m->m_pkthdr.len < ip->ip_len) { 240122702Sandre ipstat.ips_tooshort++; 241122702Sandre goto drop; 242122702Sandre } 243122702Sandre 244122702Sandre /* 245122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 246122702Sandre */ 247122702Sandre if (m->m_pkthdr.len > ip->ip_len) { 248122702Sandre if (m->m_len == m->m_pkthdr.len) { 249122702Sandre m->m_len = ip->ip_len; 250122702Sandre m->m_pkthdr.len = ip->ip_len; 251122702Sandre } else 252122702Sandre m_adj(m, ip->ip_len - m->m_pkthdr.len); 253122702Sandre } 254122702Sandre 255122702Sandre /* 256122702Sandre * Is packet from or to 127/8? 257122702Sandre */ 258122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 259122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 260122702Sandre ipstat.ips_badaddr++; 261122702Sandre goto drop; 262122702Sandre } 263122702Sandre 264122702Sandre /* 265122702Sandre * Step 2: fallback conditions to normal ip_input path processing 266122702Sandre */ 267122702Sandre 268122702Sandre /* 269122702Sandre * Only IP packets without options 270122702Sandre */ 271122702Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) 272122702Sandre goto fallback; 273122702Sandre 274122702Sandre /* 275122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 276122702Sandre * no multicast, no INADDR_ANY 277122702Sandre * 278122702Sandre * XXX: Probably some of these checks could be direct drop 279122702Sandre * conditions. However it is not clear whether there are some 280122702Sandre * hacks or obscure behaviours which make it neccessary to 281122702Sandre * let ip_input handle it. We play safe here and let ip_input 282122702Sandre * deal with it until it is proven that we can directly drop it. 283122702Sandre */ 284122702Sandre if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) || 285122702Sandre ntohl(ip->ip_src.s_addr) == (u_long)INADDR_BROADCAST || 286122702Sandre ntohl(ip->ip_dst.s_addr) == (u_long)INADDR_BROADCAST || 287122702Sandre IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 288122702Sandre IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 289122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 290122702Sandre goto fallback; 291122702Sandre 292122702Sandre /* 293122702Sandre * Is it for a local address on this host? 294122702Sandre */ 295122702Sandre LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 296122702Sandre if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 297122702Sandre goto fallback; 298122702Sandre } 299122702Sandre 300122702Sandre /* 301122702Sandre * Or is it for a local IP broadcast address on this host? 302122702Sandre */ 303122702Sandre if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) { 304122702Sandre TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 305122702Sandre if (ifa->ifa_addr->sa_family != AF_INET) 306122702Sandre continue; 307122702Sandre ia = ifatoia(ifa); 308122702Sandre if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 309122702Sandre goto fallback; 310122702Sandre if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 311122702Sandre ip->ip_dst.s_addr) 312122702Sandre goto fallback; 313122702Sandre continue; 314122702Sandrefallback: 315122702Sandre /* return packet back to netisr for slow processing */ 316122702Sandre ip->ip_len = htons(ip->ip_len); 317122702Sandre ip->ip_off = htons(ip->ip_off); 318122702Sandre return 0; 319122702Sandre } 320122702Sandre } 321122702Sandre ipstat.ips_total++; 322122702Sandre 323122702Sandre /* 324122702Sandre * Step 3: incoming packet firewall processing 325122702Sandre */ 326122702Sandre 327122702Sandre odest = dest = ip->ip_dst.s_addr; 328122702Sandre#ifdef PFIL_HOOKS 329122702Sandre /* 330122702Sandre * Run through list of ipfilter hooks for input packets 331122702Sandre */ 332122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN) || 333122702Sandre m == NULL) 334122702Sandre return 1; 335122702Sandre 336122702Sandre M_ASSERTVALID(m); 337122702Sandre M_ASSERTPKTHDR(m); 338122702Sandre 339122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 340122702Sandre dest = ip->ip_dst.s_addr; 341122702Sandre#endif 342122702Sandre 343122702Sandre /* 344122702Sandre * Run through ipfw for input packets 345122702Sandre */ 346122702Sandre if (fw_enable && IPFW_LOADED) { 347122702Sandre bzero(&args, sizeof(args)); 348122702Sandre args.m = m; 349122702Sandre 350122702Sandre ipfw = ip_fw_chk_ptr(&args); 351122702Sandre m = args.m; 352122702Sandre 353122702Sandre M_ASSERTVALID(m); 354122702Sandre M_ASSERTPKTHDR(m); 355122702Sandre 356122702Sandre /* 357122702Sandre * Packet denied, drop it 358122702Sandre */ 359122702Sandre if ((ipfw & IP_FW_PORT_DENY_FLAG) || m == NULL) 360122702Sandre goto drop; 361122702Sandre /* 362122702Sandre * Send packet to the appropriate pipe 363122702Sandre */ 364122702Sandre if (DUMMYNET_LOADED && (ipfw & IP_FW_PORT_DYNT_FLAG) != 0) { 365122702Sandre ip_dn_io_ptr(m, ipfw & 0xffff, DN_TO_IP_IN, &args); 366122702Sandre return 1; 367122702Sandre } 368122702Sandre#ifdef IPDIVERT 369122702Sandre /* 370122702Sandre * Divert packet 371122702Sandre */ 372122702Sandre if (ipfw != 0 && (ipfw & IP_FW_PORT_DYNT_FLAG) == 0) { 373122702Sandre /* 374122702Sandre * See if this is a fragment 375122702Sandre */ 376122702Sandre if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 377122702Sandre MGETHDR(tag, M_DONTWAIT, MT_TAG); 378122702Sandre if (tag == NULL) 379122702Sandre goto drop; 380122702Sandre tag->m_flags = PACKET_TAG_DIVERT; 381122702Sandre tag->m_data = (caddr_t)(u_long)args.divert_rule; 382122702Sandre tag->m_next = m; 383122702Sandre /* XXX: really bloody hack, see ip_input */ 384122702Sandre tag->m_nextpkt = (struct mbuf *)1; 385122702Sandre m = tag; 386122702Sandre tag = NULL; 387122702Sandre 388122702Sandre goto droptoours; 389122702Sandre } 390122702Sandre /* 391122702Sandre * Tee packet 392122702Sandre */ 393122702Sandre if ((ipfw & IP_FW_PORT_TEE_FLAG) != 0) 394122702Sandre teem = m_dup(m, M_DONTWAIT); 395122702Sandre else 396122702Sandre teem = m; 397122702Sandre if (teem == NULL) 398122702Sandre goto passin; 399122702Sandre 400122702Sandre /* 401122702Sandre * Delayed checksums are not compatible 402122702Sandre */ 403122702Sandre if (teem->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 404122702Sandre in_delayed_cksum(teem); 405122702Sandre teem->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 406122702Sandre } 407122702Sandre /* 408122702Sandre * Restore packet header fields to original values 409122702Sandre */ 410122702Sandre tip = mtod(teem, struct ip *); 411122702Sandre tip->ip_len = htons(tip->ip_len); 412122702Sandre tip->ip_off = htons(tip->ip_off); 413122702Sandre /* 414122702Sandre * Deliver packet to divert input routine 415122702Sandre */ 416122702Sandre divert_packet(teem, 0, ipfw & 0xffff, args.divert_rule); 417122702Sandre /* 418122702Sandre * If this was not tee, we are done 419122702Sandre */ 420122702Sandre if ((ipfw & IP_FW_PORT_TEE_FLAG) == 0) 421122702Sandre return 1; 422122702Sandre /* Continue if it was tee */ 423122702Sandre goto passin; 424122702Sandre } 425122702Sandre#endif 426122702Sandre if (ipfw == 0 && args.next_hop != NULL) { 427122702Sandre dest = args.next_hop->sin_addr.s_addr; 428122702Sandre goto passin; 429122702Sandre } 430122702Sandre /* 431122702Sandre * Let through or not? 432122702Sandre */ 433122702Sandre if (ipfw != 0) 434122702Sandre goto drop; 435122702Sandre } 436122702Sandrepassin: 437122702Sandre ip = mtod(m, struct ip *); /* if m changed during fw processing */ 438122702Sandre 439122702Sandre /* 440122702Sandre * Destination address changed? 441122702Sandre */ 442122702Sandre if (odest != dest) { 443122702Sandre /* 444122702Sandre * Is it now for a local address on this host? 445122702Sandre */ 446122702Sandre LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 447122702Sandre if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) 448122702Sandre goto forwardlocal; 449122702Sandre } 450122702Sandre /* 451122702Sandre * Go on with new destination address 452122702Sandre */ 453122702Sandre } 454122702Sandre 455122702Sandre /* 456122702Sandre * Step 4: decrement TTL and look up route 457122702Sandre */ 458122702Sandre 459122702Sandre /* 460122702Sandre * Check TTL 461122702Sandre */ 462122702Sandre#ifdef IPSTEALTH 463122702Sandre if (!ipstealth) { 464122702Sandre#endif 465122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 466122702Sandre icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, NULL, NULL); 467122702Sandre return 1; 468122702Sandre } 469122702Sandre 470122702Sandre /* 471122702Sandre * Decrement the TTL and incrementally change the checksum. 472122702Sandre * Don't bother doing this with hw checksum offloading. 473122702Sandre */ 474122702Sandre ip->ip_ttl -= IPTTLDEC; 475122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 476122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 477122702Sandre else 478122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 479122702Sandre#ifdef IPSTEALTH 480122702Sandre } 481122702Sandre#endif 482122702Sandre 483122702Sandre /* 484122702Sandre * Find route to destination. 485122702Sandre */ 486122702Sandre bzero(&ro, sizeof(ro)); 487122702Sandre dst = (struct sockaddr_in *)&ro.ro_dst; 488122702Sandre dst->sin_family = AF_INET; 489122702Sandre dst->sin_len = sizeof(*dst); 490122702Sandre dst->sin_addr.s_addr = dest; 491122702Sandre rtalloc_ign(&ro, (RTF_PRCLONING | RTF_CLONING)); 492122702Sandre 493122702Sandre /* 494122702Sandre * Route there and interface still up? 495122702Sandre */ 496122702Sandre if (ro.ro_rt && 497122702Sandre (ro.ro_rt->rt_flags & RTF_UP) && 498122702Sandre (ro.ro_rt->rt_ifp->if_flags & IFF_UP)) { 499122702Sandre ia = ifatoia(ro.ro_rt->rt_ifa); 500122702Sandre ifp = ro.ro_rt->rt_ifp; 501122702Sandre if (ro.ro_rt->rt_flags & RTF_GATEWAY) 502122702Sandre dst = (struct sockaddr_in *)ro.ro_rt->rt_gateway; 503122702Sandre } else { 504122702Sandre ipstat.ips_noroute++; 505122702Sandre ipstat.ips_cantforward++; 506122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, NULL, NULL); 507122702Sandre if (ro.ro_rt) 508122702Sandre RTFREE(ro.ro_rt); 509122702Sandre return 1; 510122702Sandre } 511122702Sandre 512122702Sandre /* 513122702Sandre * Step 5: outgoing firewall packet processing 514122702Sandre */ 515122702Sandre 516122702Sandre#ifdef PFIL_HOOKS 517122702Sandre /* 518122702Sandre * Run through list of hooks for output packets. 519122702Sandre */ 520122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT) || m == NULL) { 521122702Sandre RTFREE(ro.ro_rt); 522122702Sandre return 1; 523122702Sandre } 524122702Sandre 525122702Sandre M_ASSERTVALID(m); 526122702Sandre M_ASSERTPKTHDR(m); 527122702Sandre 528122702Sandre ip = mtod(m, struct ip *); 529122702Sandre dest = ip->ip_dst.s_addr; 530122702Sandre#endif 531122702Sandre if (fw_enable && IPFW_LOADED && !args.next_hop) { 532122759Sandre bzero(&args, sizeof(args)); 533122702Sandre args.m = m; 534122702Sandre args.oif = ifp; 535122702Sandre 536122702Sandre ipfw = ip_fw_chk_ptr(&args); 537122702Sandre m = args.m; 538122702Sandre 539122702Sandre M_ASSERTVALID(m); 540122702Sandre M_ASSERTPKTHDR(m); 541122702Sandre 542122702Sandre if ((ipfw & IP_FW_PORT_DENY_FLAG) || m == NULL) { 543122702Sandre RTFREE(ro.ro_rt); 544122702Sandre goto drop; 545122702Sandre } 546122702Sandre if (DUMMYNET_LOADED && (ipfw & IP_FW_PORT_DYNT_FLAG) != 0) { 547122702Sandre /* 548122702Sandre * XXX note: if the ifp or rt entry are deleted 549122702Sandre * while a pkt is in dummynet, we are in trouble! 550122702Sandre */ 551122702Sandre args.ro = &ro; /* dummynet does not save it */ 552122702Sandre args.dst = dst; 553122702Sandre 554122702Sandre ip_dn_io_ptr(m, ipfw & 0xffff, DN_TO_IP_OUT, &args); 555122702Sandre RTFREE(ro.ro_rt); 556122702Sandre return 1; 557122702Sandre } 558122702Sandre#ifdef IPDIVERT 559122702Sandre if (ipfw != 0 && (ipfw & IP_FW_PORT_DYNT_FLAG) == 0) { 560122702Sandre /* 561122702Sandre * See if this is a fragment 562122702Sandre */ 563122702Sandre if (ip->ip_off & (IP_MF | IP_OFFMASK)) { 564122702Sandre MGETHDR(tag, M_DONTWAIT, MT_TAG); 565122702Sandre if (tag == NULL) { 566122702Sandre RTFREE(ro.ro_rt); 567122702Sandre goto drop; 568122702Sandre } 569122702Sandre tag->m_flags = PACKET_TAG_DIVERT; 570122759Sandre tag->m_data = (caddr_t)(u_long)args.divert_rule; 571122702Sandre tag->m_next = m; 572122702Sandre /* XXX: really bloody hack, see ip_input */ 573122702Sandre tag->m_nextpkt = (struct mbuf *)1; 574122702Sandre m = tag; 575122702Sandre tag = NULL; 576122702Sandre 577122702Sandre goto droptoours; 578122702Sandre } 579122702Sandre /* 580122702Sandre * Tee packet 581122702Sandre */ 582122702Sandre if ((ipfw & IP_FW_PORT_TEE_FLAG) != 0) 583122702Sandre teem = m_dup(m, M_DONTWAIT); 584122702Sandre else 585122702Sandre teem = m; 586122702Sandre if (teem == NULL) 587122702Sandre goto passout; 588122702Sandre 589122702Sandre /* 590122702Sandre * Delayed checksums are not compatible with divert 591122702Sandre */ 592122702Sandre if (teem->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 593122702Sandre in_delayed_cksum(teem); 594122702Sandre teem->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 595122702Sandre } 596122702Sandre /* 597122702Sandre * Restore packet header fields to original values 598122702Sandre */ 599122702Sandre tip = mtod(teem, struct ip *); 600122702Sandre tip->ip_len = htons(tip->ip_len); 601122702Sandre tip->ip_off = htons(tip->ip_off); 602122702Sandre /* 603122702Sandre * Deliver packet to divert input routine 604122702Sandre */ 605122702Sandre divert_packet(teem, 0, ipfw & 0xffff, args.divert_rule); 606122702Sandre /* 607122702Sandre * If this was not tee, we are done 608122702Sandre */ 609122702Sandre if ((ipfw & IP_FW_PORT_TEE_FLAG) == 0) { 610122702Sandre RTFREE(ro.ro_rt); 611122702Sandre return 1; 612122702Sandre } 613122702Sandre /* Continue if it was tee */ 614122702Sandre goto passout; 615122702Sandre } 616122702Sandre#endif 617122702Sandre if (ipfw == 0 && args.next_hop != NULL) { 618122702Sandre dest = args.next_hop->sin_addr.s_addr; 619122702Sandre goto passout; 620122702Sandre } 621122702Sandre /* 622122702Sandre * Let through or not? 623122702Sandre */ 624122702Sandre if (ipfw != 0) 625122702Sandre goto drop; 626122702Sandre } 627122702Sandrepassout: 628122702Sandre ip = mtod(m, struct ip *); 629122702Sandre 630122702Sandre /* 631122702Sandre * Destination address changed? 632122702Sandre */ 633122702Sandre if (odest != dest) { 634122702Sandre /* 635122702Sandre * Is it now for a local address on this host? 636122702Sandre */ 637122702Sandre LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) { 638122702Sandre if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr) { 639122702Sandreforwardlocal: 640122702Sandre if (args.next_hop) { 641122702Sandre /* XXX leak */ 642122702Sandre MGETHDR(tag, M_DONTWAIT, MT_TAG); 643122702Sandre if (tag == NULL) { 644122702Sandre if (ro.ro_rt) 645122702Sandre RTFREE(ro.ro_rt); 646122702Sandre goto drop; 647122702Sandre } 648122702Sandre tag->m_flags = PACKET_TAG_IPFORWARD; 649122702Sandre tag->m_data = (caddr_t)args.next_hop; 650122702Sandre tag->m_next = m; 651122702Sandre /* XXX: really bloody hack, 652122702Sandre * see ip_input */ 653122702Sandre tag->m_nextpkt = (struct mbuf *)1; 654122702Sandre m = tag; 655122702Sandre tag = NULL; 656122702Sandre } 657122702Sandre#ifdef IPDIVERT 658122702Sandredroptoours: /* Used for DIVERT */ 659122702Sandre#endif 660122702Sandre MGETHDR(tag, M_DONTWAIT, MT_TAG); 661122702Sandre if (tag == NULL) { 662122702Sandre if (ro.ro_rt) 663122702Sandre RTFREE(ro.ro_rt); 664122702Sandre goto drop; 665122702Sandre } 666122702Sandre tag->m_flags = PACKET_TAG_IPFASTFWD_OURS; 667122702Sandre tag->m_data = NULL; 668122702Sandre tag->m_next = m; 669122702Sandre /* XXX: really bloody hack, see ip_input */ 670122702Sandre tag->m_nextpkt = (struct mbuf *)1; 671122702Sandre m = tag; 672122702Sandre tag = NULL; 673122702Sandre 674122702Sandre /* ip still points to the real packet */ 675122702Sandre ip->ip_len = htons(ip->ip_len); 676122702Sandre ip->ip_off = htons(ip->ip_off); 677122702Sandre 678122702Sandre /* 679122702Sandre * Return packet for processing by ip_input 680122702Sandre */ 681122702Sandre if (ro.ro_rt) 682122702Sandre RTFREE(ro.ro_rt); 683122702Sandre return 0; 684122702Sandre } 685122702Sandre } 686122702Sandre /* 687122702Sandre * Redo route lookup with new destination address 688122702Sandre */ 689122702Sandre RTFREE(ro.ro_rt); 690122702Sandre bzero(&ro, sizeof(ro)); 691122702Sandre dst = (struct sockaddr_in *)&ro.ro_dst; 692122702Sandre dst->sin_family = AF_INET; 693122702Sandre dst->sin_len = sizeof(*dst); 694122702Sandre dst->sin_addr.s_addr = dest; 695122702Sandre rtalloc_ign(&ro, (RTF_PRCLONING | RTF_CLONING)); 696122702Sandre 697122702Sandre /* 698122702Sandre * Route there and interface still up? 699122702Sandre */ 700122702Sandre if (ro.ro_rt && 701122702Sandre (ro.ro_rt->rt_flags & RTF_UP) && 702122702Sandre (ro.ro_rt->rt_ifp->if_flags & IFF_UP)) { 703122702Sandre ia = ifatoia(ro.ro_rt->rt_ifa); 704122702Sandre ifp = ro.ro_rt->rt_ifp; 705122702Sandre if (ro.ro_rt->rt_flags & RTF_GATEWAY) 706122702Sandre dst = (struct sockaddr_in *)ro.ro_rt->rt_gateway; 707122702Sandre } else { 708122702Sandre ipstat.ips_noroute++; 709122702Sandre ipstat.ips_cantforward++; 710122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 711122702Sandre NULL, NULL); 712122702Sandre if (ro.ro_rt) 713122702Sandre RTFREE(ro.ro_rt); 714122702Sandre return 1; 715122702Sandre } 716122702Sandre } 717122702Sandre 718122702Sandre /* 719122702Sandre * Step 6: send off the packet 720122702Sandre */ 721122702Sandre 722122702Sandre /* 723122702Sandre * Check if packet fits MTU or if hardware will fragement for us 724122702Sandre */ 725122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 726122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 727122702Sandre else 728122702Sandre mtu = ifp->if_mtu; 729122702Sandre 730122702Sandre if (ip->ip_len <= mtu || 731122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 732122702Sandre /* 733122702Sandre * Restore packet header fields to original values 734122702Sandre */ 735122702Sandre ip->ip_len = htons(ip->ip_len); 736122702Sandre ip->ip_off = htons(ip->ip_off); 737122702Sandre /* 738122702Sandre * Send off the packet via outgoing interface 739122702Sandre */ 740122702Sandre error = (*ifp->if_output)(ifp, m, 741122702Sandre (struct sockaddr *)dst, ro.ro_rt); 742122702Sandre if (ia) { 743122702Sandre ia->ia_ifa.if_opackets++; 744122702Sandre ia->ia_ifa.if_obytes += m->m_pkthdr.len; 745122702Sandre } 746122702Sandre } else { 747122702Sandre /* 748122702Sandre * Handle EMSGSIZE with icmp reply 749122702Sandre * needfrag for TCP MTU discovery 750122702Sandre */ 751122702Sandre if (ip->ip_off & IP_DF) { 752122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 753122702Sandre NULL, ifp); 754122702Sandre ipstat.ips_cantfrag++; 755122702Sandre RTFREE(ro.ro_rt); 756122702Sandre return 1; 757122702Sandre } else { 758122702Sandre /* 759122702Sandre * We have to fragement the packet 760122702Sandre */ 761122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 762122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 763122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 764122702Sandre RTFREE(ro.ro_rt); 765122702Sandre goto drop; 766122702Sandre } 767122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 768122702Sandre /* 769122702Sandre * Send off the fragments via outgoing interface 770122702Sandre */ 771122702Sandre error = 0; 772122702Sandre do { 773122702Sandre m0 = m->m_nextpkt; 774122702Sandre m->m_nextpkt = NULL; 775122702Sandre 776122702Sandre error = (*ifp->if_output)(ifp, m, 777122702Sandre (struct sockaddr *)dst, ro.ro_rt); 778122702Sandre if (error) 779122702Sandre break; 780122702Sandre } while ((m = m0) != NULL); 781122702Sandre if (error) { 782122702Sandre /* Reclaim remaining fragments */ 783122702Sandre for (; m; m = m0) { 784122702Sandre m0 = m->m_nextpkt; 785122702Sandre m->m_nextpkt = NULL; 786122702Sandre m_freem(m); 787122702Sandre } 788122702Sandre } else 789122702Sandre ipstat.ips_fragmented++; 790122702Sandre } 791122702Sandre } 792122702Sandre 793122702Sandre if (error != 0) 794122702Sandre ipstat.ips_odropped++; 795122702Sandre else { 796122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 797122702Sandre ipstat.ips_forward++; 798122702Sandre ipstat.ips_fastforward++; 799122702Sandre } 800122702Sandre RTFREE(ro.ro_rt); 801122702Sandre return 1; 802122702Sandredrop: 803122702Sandre if (m) 804122702Sandre m_freem(m); 805122702Sandre return 1; 806122702Sandre} 807