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1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 | /* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * ROUTE - implementation of the IP router. * * Version: @(#)route.c 1.0.14 05/31/93 * * Authors: Ross Biro, <bir7@leland.Stanford.Edu> * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> * Alan Cox, <gw4pts@gw4pts.ampr.org> * Linus Torvalds, <Linus.Torvalds@helsinki.fi> * Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * * Fixes: * Alan Cox : Verify area fixes. * Alan Cox : cli() protects routing changes * Rui Oliveira : ICMP routing table updates * (rco@di.uminho.pt) Routing table insertion and update * Linus Torvalds : Rewrote bits to be sensible * Alan Cox : Added BSD route gw semantics * Alan Cox : Super /proc >4K * Alan Cox : MTU in route table * Alan Cox : MSS actually. Also added the window * clamper. * Sam Lantinga : Fixed route matching in rt_del() * Alan Cox : Routing cache support. * Alan Cox : Removed compatibility cruft. * Alan Cox : RTF_REJECT support. * Alan Cox : TCP irtt support. * Jonathan Naylor : Added Metric support. * Miquel van Smoorenburg : BSD API fixes. * Miquel van Smoorenburg : Metrics. * Alan Cox : Use __u32 properly * Alan Cox : Aligned routing errors more closely with BSD * our system is still very different. * Alan Cox : Faster /proc handling * Alexey Kuznetsov : Massive rework to support tree based routing, * routing caches and better behaviour. * * Olaf Erb : irtt wasn't being copied right. * Bjorn Ekwall : Kerneld route support. * Alan Cox : Multicast fixed (I hope) * Pavel Krauz : Limited broadcast fixed * Alexey Kuznetsov : End of old history. Splitted to fib.c and * route.c and rewritten from scratch. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/config.h> #include <asm/uaccess.h> #include <asm/system.h> #include <asm/bitops.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/string.h> #include <linux/socket.h> #include <linux/sockios.h> #include <linux/errno.h> #include <linux/in.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/if_arp.h> #include <linux/proc_fs.h> #include <net/ip.h> #include <net/protocol.h> #include <net/route.h> #include <net/arp.h> #include <net/tcp.h> #include <linux/skbuff.h> #include <net/sock.h> #include <net/icmp.h> #include <linux/net_alias.h> /* Compile time configuretion flags */ #define CONFIG_IP_LOCAL_RT_POLICY 1 static void rt_run_flush(unsigned long); static struct timer_list rt_flush_timer = { NULL, NULL, RT_FLUSH_DELAY, 0L, rt_run_flush }; /* * Interface to generic destination cache. */ static void ipv4_dst_destroy(struct dst_entry * dst); static struct dst_entry * ipv4_dst_check(struct dst_entry * dst, u32); static struct dst_entry * ipv4_dst_reroute(struct dst_entry * dst, struct sk_buff *); struct dst_ops ipv4_dst_ops = { AF_INET, ipv4_dst_check, ipv4_dst_reroute, ipv4_dst_destroy }; /* * Route cache. */ static atomic_t rt_cache_size; static struct rtable *rt_hash_table[RT_HASH_DIVISOR]; static struct rtable * rt_intern_hash(unsigned hash, struct rtable * rth, u16 protocol); static __inline__ unsigned rt_hash_code(u32 daddr, u32 saddr, u8 tos) { unsigned hash = ((daddr&0xF0F0F0F0)>>4)|((daddr&0x0F0F0F0F)<<4); hash = hash^saddr^tos; hash = hash^(hash>>16); return (hash^(hash>>8)) & 0xFF; } #ifdef CONFIG_PROC_FS static int rt_cache_get_info(char *buffer, char **start, off_t offset, int length, int dummy) { int len=0; off_t pos=0; char temp[129]; struct rtable *r; int i; pos = 128; if (offset<128) { sprintf(buffer,"%-127s\n", "Iface\tDestination\tGateway \tFlags\t\tRefCnt\tUse\tMetric\tSource\t\tMTU\tWindow\tIRTT\tTOS\tHHRef\tHHUptod\tSpecDst\tHash"); len = 128; } start_bh_atomic(); for (i = 0; i<RT_HASH_DIVISOR; i++) { for (r = rt_hash_table[i]; r; r = r->u.rt_next) { /* * Spin through entries until we are ready */ pos += 128; if (pos <= offset) { len = 0; continue; } sprintf(temp, "%s\t%08lX\t%08lX\t%8X\t%d\t%u\t%d\t%08lX\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X\t%02X", r->u.dst.dev ? r->u.dst.dev->name : "*", (unsigned long)r->rt_dst, (unsigned long)r->rt_gateway, r->rt_flags, r->u.dst.refcnt, r->u.dst.use, 0, (unsigned long)r->rt_src, (int)r->u.dst.pmtu, r->u.dst.window, (int)r->u.dst.rtt, r->key.tos, r->u.dst.hh ? r->u.dst.hh->hh_refcnt : -1, r->u.dst.hh ? r->u.dst.hh->hh_uptodate : 0, r->rt_spec_dst, i); sprintf(buffer+len,"%-127s\n",temp); len += 128; if (pos >= offset+length) goto done; } } done: end_bh_atomic(); *start = buffer+len-(pos-offset); len = pos-offset; if (len>length) len = length; return len; } #endif static void __inline__ rt_free(struct rtable *rt) { dst_free(&rt->u.dst); } void ip_rt_check_expire() { int i; static int rover; struct rtable *rth, **rthp; unsigned long now = jiffies; start_bh_atomic(); for (i=0; i<RT_HASH_DIVISOR/5; i++) { rover = (rover + 1) & (RT_HASH_DIVISOR-1); rthp = &rt_hash_table[rover]; while ((rth = *rthp) != NULL) { struct rtable * rth_next = rth->u.rt_next; /* * Cleanup aged off entries. */ if (!rth->u.dst.use && now - rth->u.dst.lastuse > RT_CACHE_TIMEOUT) { *rthp = rth_next; atomic_dec(&rt_cache_size); #if RT_CACHE_DEBUG >= 2 printk("rt_check_expire clean %02x@%08x\n", rover, rth->rt_dst); #endif rt_free(rth); continue; } if (!rth_next) break; /* * Pseudo-LRU ordering. * Really we should teach it to move * rarely used but permanently living entries * (f.e. rdisc, igmp etc.) to the end of list. */ if ( rth_next->u.dst.lastuse - rth->u.dst.lastuse > RT_CACHE_BUBBLE_THRESHOLD || (rth->u.dst.lastuse - rth_next->u.dst.lastuse < 0 && rth->u.dst.use < rth_next->u.dst.use)) { #if RT_CACHE_DEBUG >= 2 printk("rt_check_expire bubbled %02x@%08x<->%08x\n", rover, rth->rt_dst, rth_next->rt_dst); #endif *rthp = rth_next; rth->u.rt_next = rth_next->u.rt_next; rth_next->u.rt_next = rth; sti(); rthp = &rth_next->u.rt_next; continue; } rthp = &rth->u.rt_next; } } end_bh_atomic(); } void rt_cache_flush(int how) { start_bh_atomic(); if (rt_flush_timer.expires) { if (jiffies - rt_flush_timer.expires > 0 || rt_flush_timer.expires - jiffies > RT_FLUSH_DELAY/2) how = 1; } if (how) { if (rt_flush_timer.expires) del_timer(&rt_flush_timer); rt_flush_timer.expires = 0; end_bh_atomic(); rt_run_flush(0); return; } if (rt_flush_timer.expires) { end_bh_atomic(); return; } del_timer(&rt_flush_timer); rt_flush_timer.expires = jiffies + RT_FLUSH_DELAY; add_timer(&rt_flush_timer); end_bh_atomic(); } void rt_run_flush(unsigned long dummy) { int i; struct rtable * rth, * next; for (i=0; i<RT_HASH_DIVISOR; i++) { int nr=0; cli(); if (!(rth = rt_hash_table[i])) { sti(); continue; } rt_hash_table[i] = NULL; sti(); for (; rth; rth=next) { next = rth->u.rt_next; atomic_dec(&rt_cache_size); nr++; rth->u.rt_next = NULL; rt_free(rth); } #if RT_CACHE_DEBUG >= 2 if (nr > 0) printk("rt_cache_flush: %d@%02x\n", nr, i); #endif } } static void rt_garbage_collect(void) { int i; static unsigned expire = RT_CACHE_TIMEOUT>>1; static unsigned long last_gc; struct rtable *rth, **rthp; unsigned long now; start_bh_atomic(); now = jiffies; /* * Garbage collection is pretty expensive, * do not make it too frequently. */ if (now - last_gc < 1*HZ) { expire >>= 1; end_bh_atomic(); return; } expire++; for (i=0; i<RT_HASH_DIVISOR; i++) { if (!rt_hash_table[i]) continue; for (rthp=&rt_hash_table[i]; (rth=*rthp); rthp=&rth->u.rt_next) { if (rth->u.dst.use || now - rth->u.dst.lastuse > expire) continue; atomic_dec(&rt_cache_size); *rthp = rth->u.rt_next; rth->u.rt_next = NULL; rt_free(rth); break; } } last_gc = now; if (rt_cache_size < RT_CACHE_MAX_SIZE) expire = RT_CACHE_TIMEOUT>>1; else expire >>= 1; end_bh_atomic(); } static int rt_ll_bind(struct rtable *rt) { struct neighbour *neigh; struct hh_cache *hh = NULL; if (rt->u.dst.dev && rt->u.dst.dev->hard_header_cache) { neigh = rt->u.dst.neighbour; if (!neigh) neigh = arp_find_neighbour(&rt->u.dst, 1); if (neigh) { rt->u.dst.neighbour = neigh; for (hh=neigh->hh; hh; hh = hh->hh_next) if (hh->hh_type == ETH_P_IP) break; } if (!hh && (hh = kmalloc(sizeof(*hh), GFP_ATOMIC)) != NULL) { #if RT_CACHE_DEBUG >= 2 extern atomic_t hh_count; atomic_inc(&hh_count); #endif memset(hh, 0, sizeof(struct hh_cache)); hh->hh_type = ETH_P_IP; hh->hh_refcnt = 0; hh->hh_next = NULL; if (rt->u.dst.dev->hard_header_cache(&rt->u.dst, neigh, hh)) { kfree(hh); #if RT_CACHE_DEBUG >= 2 atomic_dec(&hh_count); #endif hh = NULL; } else if (neigh) { atomic_inc(&hh->hh_refcnt); hh->hh_next = neigh->hh; neigh->hh = hh; } } if (hh) { atomic_inc(&hh->hh_refcnt); rt->u.dst.hh = hh; return hh->hh_uptodate; } } return 0; } static struct rtable *rt_intern_hash(unsigned hash, struct rtable * rt, u16 protocol) { struct rtable *rth, **rthp; unsigned long now = jiffies; rt->u.dst.priority = rt_tos2priority(rt->key.tos); start_bh_atomic(); rthp = &rt_hash_table[hash]; while ((rth = *rthp) != NULL) { if (memcmp(&rth->key, &rt->key, sizeof(rt->key)) == 0) { /* Put it first */ *rthp = rth->u.rt_next; rth->u.rt_next = rt_hash_table[hash]; rt_hash_table[hash] = rth; atomic_inc(&rth->u.dst.refcnt); atomic_inc(&rth->u.dst.use); rth->u.dst.lastuse = now; end_bh_atomic(); ip_rt_put(rt); rt_free(rt); return rth; } rthp = &rth->u.rt_next; } if (rt_cache_size >= RT_CACHE_MAX_SIZE) rt_garbage_collect(); rt->u.rt_next = rt_hash_table[hash]; #if RT_CACHE_DEBUG >= 2 if (rt->u.rt_next) { struct rtable * trt; printk("rt_cache @%02x: %08x", hash, rt->rt_dst); for (trt=rt->u.rt_next; trt; trt=trt->u.rt_next) printk(" . %08x", trt->rt_dst); printk("\n"); } #endif rt_hash_table[hash] = rt; atomic_inc(&rt_cache_size); if (protocol == ETH_P_IP) rt_ll_bind(rt); end_bh_atomic(); return rt; } void ip_rt_redirect(u32 old_gw, u32 daddr, u32 new_gw, u32 saddr, u8 tos, struct device *dev) { int i; int off_link = 0; struct fib_info *fi; struct rtable *rth, **rthp; u32 skeys[2] = { saddr, 0, }; struct device *pdev = net_alias_main_dev(dev); tos &= IPTOS_TOS_MASK; if (new_gw == old_gw || !ipv4_config.accept_redirects || MULTICAST(new_gw) || BADCLASS(new_gw) || ZERONET(new_gw)) goto reject_redirect; if ((new_gw^dev->pa_addr)&dev->pa_mask) off_link = 1; if (!ipv4_config.rfc1620_redirects) { if (off_link) goto reject_redirect; if (ipv4_config.secure_redirects && ip_fib_chk_default_gw(new_gw, dev)) goto reject_redirect; } fi = fib_lookup_info(new_gw, 0, 0, &loopback_dev, NULL); if (fi == NULL || fi->fib_flags&(RTF_LOCAL|RTF_BROADCAST|RTF_NAT)) goto reject_redirect; for (i=0; i<2; i++) { unsigned hash = rt_hash_code(daddr, skeys[i], tos); rthp=&rt_hash_table[hash]; while ( (rth = *rthp) != NULL) { struct rtable *rt; if (rth->key.dst != daddr || rth->key.src != skeys[i] || rth->key.tos != tos || rth->key.dst_dev != NULL || rth->key.src_dev != NULL) { rthp = &rth->u.rt_next; continue; } if (rth->rt_dst != daddr || rth->rt_src != saddr || rth->rt_flags&RTF_REJECT || rth->rt_gateway != old_gw || rth->u.dst.dev != dev) break; rt = dst_alloc(sizeof(struct rtable), &ipv4_dst_ops); if (rt == NULL) return; /* * Copy all the information. */ rt->u.dst.refcnt = 1; rt->u.dst.dev = dev; rt->u.dst.input = rth->u.dst.input; rt->u.dst.output = rth->u.dst.output; rt->u.dst.pmtu = dev->mtu; rt->u.dst.rtt = TCP_TIMEOUT_INIT; rt->u.dst.window = 0; rt->u.dst.use = 1; rt->u.dst.lastuse = jiffies; rt->rt_flags = rth->rt_flags|RTF_DYNAMIC|RTF_MODIFIED; rt->rt_flags &= ~RTF_GATEWAY; if (new_gw != daddr) rt->rt_flags |= RTF_GATEWAY; rt->rt_src = rth->rt_src; rt->rt_dst = rth->rt_dst; rt->rt_src_dev = rth->rt_src_dev; rt->rt_spec_dst = rth->rt_spec_dst; rt->key = rth->key; /* But gateway is different ... */ rt->rt_gateway = new_gw; if (off_link) { if (fi->fib_dev != dev && net_alias_main_dev(fi->fib_dev) == pdev) rt->u.dst.dev = fi->fib_dev; } if (ipv4_config.rfc1620_redirects && !rt_ll_bind(rt)) { ip_rt_put(rt); rt_free(rt); break; } *rthp = rth->u.rt_next; rt_free(rth); rt = rt_intern_hash(hash, rt, ETH_P_IP); ip_rt_put(rt); break; } } return; reject_redirect: if (ipv4_config.log_martians) printk(KERN_INFO "Redirect from %lX/%s to %lX ignored." "Path = %lX -> %lX, tos %02x\n", ntohl(old_gw), dev->name, ntohl(new_gw), ntohl(saddr), ntohl(daddr), tos); } void ip_rt_advice(struct rtable **rp, int advice) { struct rtable *rt; if (advice) return; start_bh_atomic(); if ((rt = *rp) != NULL && (rt->rt_flags&(RTF_DYNAMIC|RTF_MODIFIED))) { #if RT_CACHE_DEBUG >= 1 printk(KERN_DEBUG "ip_rt_advice: redirect to %08x/%02x dropped\n", rt->rt_dst, rt->key.tos); #endif *rp = NULL; ip_rt_put(rt); rt_cache_flush(0); } end_bh_atomic(); return; } /* * Algorithm: * 1. The first RT_REDIRECT_NUMBER redirects are sent * with exponential backoff, then we stop sending them at all, * assuming that the host ignores our redirects. * 2. If we did not see a packets requiring redirects * during RT_REDIRECT_SILENCE, we assume that the host * forgot redirected route and start to send redirects again. * * This algorithm is much cheaper and more intelligent than dumb load limiting * in icmp.c. * * NOTE. Do not forget to inhibit load limiting for redirects (redundant) * and "frag. need" (breaks PMTU discovery) in icmp.c. */ void ip_rt_send_redirect(struct sk_buff *skb) { struct rtable *rt = (struct rtable*)skb->dst; /* No redirected packets during RT_REDIRECT_SILENCE; * reset the algorithm. */ if (jiffies - rt->last_error > RT_REDIRECT_SILENCE) rt->errors = 0; /* Too many ignored redirects; do not send anything * set last_error to the last seen redirected packet. */ if (rt->errors >= RT_REDIRECT_NUMBER) { rt->last_error = jiffies; return; } /* Check for load limit; set last_error to the latest sent * redirect. */ if (jiffies - rt->last_error > (RT_REDIRECT_LOAD<<rt->errors)) { icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway); rt->last_error = jiffies; if (ipv4_config.log_martians && ++rt->errors == RT_REDIRECT_NUMBER) printk(KERN_WARNING "host %08x/%s ignores redirects for %08x to %08x.\n", rt->rt_src, rt->rt_src_dev->name, rt->rt_dst, rt->rt_gateway); } } static int ip_error(struct sk_buff *skb) { struct rtable *rt = (struct rtable*)skb->dst; int code; switch (rt->u.dst.error) { case EINVAL: default: kfree_skb(skb, FREE_READ); return 0; case ENETUNREACH: code = ICMP_NET_UNREACH; break; case EACCES: code = ICMP_PKT_FILTERED; break; } if (jiffies - rt->last_error > RT_ERROR_LOAD) { icmp_send(skb, ICMP_DEST_UNREACH, code, 0); rt->last_error = jiffies; } kfree_skb(skb, FREE_READ); return 0; } static __inline__ unsigned short guess_mtu(unsigned short old_mtu) { if (old_mtu > 32000) return 32000; else if (old_mtu > 17914) return 17914; else if (old_mtu > 8166) return 8166; else if (old_mtu > 4352) return 4352; else if (old_mtu > 2002) return 2002; else if (old_mtu > 1492) return 1492; else if (old_mtu > 576) return 576; else if (old_mtu > 296) return 296; /* * These two are not from the RFC but * are needed for AMPRnet AX.25 paths. */ else if (old_mtu > 216) return 216; else if (old_mtu > 128) return 128; return 68; } unsigned short ip_rt_frag_needed(struct iphdr *iph, unsigned short new_mtu) { int i; unsigned short old_mtu = ntohs(iph->tot_len); struct rtable *rth; u32 skeys[2] = { iph->saddr, 0, }; u32 daddr = iph->daddr; u8 tos = iph->tos & IPTOS_TOS_MASK; unsigned short est_mtu = 0; if (ipv4_config.no_pmtu_disc) return 0; for (i=0; i<2; i++) { unsigned hash = rt_hash_code(daddr, skeys[i], tos); for (rth = rt_hash_table[hash]; rth; rth = rth->u.rt_next) { if (rth->key.dst == daddr && rth->key.src == skeys[i] && rth->rt_dst == daddr && rth->rt_src == iph->saddr && rth->key.tos == tos && !rth->key.src_dev && !(rth->rt_flags&RTF_NOPMTUDISC)) { unsigned short mtu = new_mtu; if (new_mtu < 68 || new_mtu >= old_mtu) { /* BSD 4.2 compatibility hack :-( */ if (mtu == 0 && old_mtu >= rth->u.dst.pmtu && old_mtu >= 68 + (iph->ihl<<2)) old_mtu -= iph->ihl<<2; mtu = guess_mtu(old_mtu); } if (mtu < rth->u.dst.pmtu) { rth->u.dst.pmtu = mtu; est_mtu = mtu; } } } } return est_mtu; } static void ipv4_dst_destroy(struct dst_entry * dst) { struct rtable * rt = (struct rtable*)dst; struct hh_cache * hh = rt->u.dst.hh; rt->u.dst.hh = NULL; if (hh && atomic_dec_and_test(&hh->hh_refcnt)) { #if RT_CACHE_DEBUG >= 2 extern atomic_t hh_count; atomic_dec(&hh_count); #endif kfree(hh); } } static struct dst_entry * ipv4_dst_check(struct dst_entry * dst, u32 cookie) { return NULL; } static struct dst_entry * ipv4_dst_reroute(struct dst_entry * dst, struct sk_buff *skb) { return NULL; } int ip_check_mc(struct device *dev, u32 mc_addr) { struct ip_mc_list *ip_mc; if (mc_addr==htonl(INADDR_ALLHOSTS_GROUP)) return 1; for (ip_mc=dev->ip_mc_list; ip_mc; ip_mc=ip_mc->next) if (ip_mc->multiaddr == mc_addr) return 1; return 0; } static int ip_rt_bug(struct sk_buff *skb) { kfree_skb(skb, FREE_WRITE); printk(KERN_DEBUG "ip_rt_bug: %08x -> %08x, %s\n", skb->nh.iph->saddr, skb->nh.iph->daddr, skb->dev ? skb->dev->name : "?"); return 0; } /* * This function is called ONLY FROM NET BH. No locking! * * NOTE. We drop all the packets that has local source * addresses, because every properly looped back packet * must have correct destination already attached by output routine. * * Such approach solves two big problems: * 1. Not simplex devices (if they exist 8)) are handled properly. * 2. IP spoofing attempts are filtered with 100% of guarantee. */ int ip_route_input_slow(struct sk_buff *skb, u32 daddr, u32 saddr, u8 tos, struct device *pdev) { struct device * dev = pdev; struct fib_info *fi = NULL; struct fib_info *src_fi = NULL; unsigned flags = 0; struct device *devout; struct rtable * rth; unsigned hash; struct fib_result res; u32 src_key = saddr; u32 dst_key = daddr; int err = -EINVAL; int log = 0; hash = rt_hash_code(daddr, saddr^(unsigned long)pdev, tos); /* Check for martians... */ if (MULTICAST(saddr) || BADCLASS(saddr) || LOOPBACK(saddr)) goto martian_source; if (MULTICAST(daddr) || daddr == 0xFFFFFFFF) goto mc_input; /* Accept zero addresses only to limited broadcast/multicasts; * I even do not know to fix it or not. */ if (ZERONET(saddr)) goto martian_source; if (BADCLASS(daddr) || ZERONET(daddr) || LOOPBACK(daddr)) goto martian_destination; /* * Device is not yet initialized, accept all addresses as ours. */ if (ZERONET(dev->pa_addr)) goto promisc_ip; /* * Now we are able to route packet. */ if ((err = fib_lookup(&res, daddr, saddr, tos, pdev, NULL)) < 0) { if (!IS_ROUTER) return -EINVAL; goto no_route; } fi = res.f->fib_info; flags = fi->fib_flags; devout = fi->fib_dev; if (flags&RTF_NAT) { daddr = htonl((ntohl(daddr)&((1<<res.fm)-1)))|fi->fib_gateway; fi = fib_lookup_info(daddr, saddr, tos, pdev, NULL); if (!fi || fi->fib_flags&(RTF_NAT|RTF_LOCAL|RTF_MULTICAST|RTF_BROADCAST)) return -EINVAL; devout = fi->fib_dev; flags = fi->fib_flags|RTCF_NAT|RTF_NAT; } switch (res.fr->cl_action) { case RTP_NAT: /* Packet is from translated source; remember it */ saddr = (saddr&~res.fr->cl_srcmask)|res.fr->cl_srcmap; flags |= RTCF_NAT; break; case RTP_MASQUERADE: /* Packet is from masqueraded source; remember it */ flags |= RTCF_MASQ; break; default: } log = res.fr->cl_flags&RTRF_LOG; if (!(flags & RTF_LOCAL)) { if (!IS_ROUTER || flags&RTF_NOFORWARD) return -EINVAL; } else { fi = NULL; devout = &loopback_dev; if (flags&RTF_BROADCAST) goto mc_input; } #ifndef CONFIG_IP_LOCAL_RT_POLICY if (flags&RTF_LOCAL) src_fi = fib_lookup_info(src_key, 0, tos, &loopback_dev, NULL); else #endif if (fib_lookup(&res, src_key, daddr, tos, net_alias_main_dev(devout), NULL) == 0) { src_fi = res.f->fib_info; /* Destination is on masqueraded network: * if it is real incoming frame, ip_forward will drop it. */ if (res.fr->cl_flags&RTRF_VALVE) flags |= RTCF_VALVE; } if (src_fi) { if (src_fi->fib_flags&(RTF_LOCAL|RTF_BROADCAST|RTF_MULTICAST|RTF_NAT)) goto martian_source; if (!(src_fi->fib_flags&RTF_GATEWAY)) flags |= RTCF_DIRECTSRC; if (net_alias_main_dev(src_fi->fib_dev) == pdev) skb->dev = dev = src_fi->fib_dev; else { /* Route to packet source goes via different interface; rfc1812 proposes to drop them. It is dangerous on not-stub/transit networks because of path asymmetry. */ if (ipv4_config.rfc1812_filter >= 2) goto martian_source; /* Weaker form of rfc1812 filtering. If source is on directly connected network, it can mean either local network configuration error (the most probable case) or real IP spoofing attempt. */ if (ipv4_config.rfc1812_filter >= 1 && !(flags&RTCF_DIRECTSRC)) goto martian_source; } } else if (ipv4_config.rfc1812_filter >= 1) goto martian_source; make_route: if (skb->protocol != __constant_htons(ETH_P_IP)) { /* ARP request. Do not make route for invalid destination or * if it is redirected. */ if (flags&(RTF_REJECT|RTF_BROADCAST|RTF_MULTICAST) || skb->pkt_type == PACKET_OTHERHOST || (devout == dev && !(flags&(RTF_LOCAL|RTCF_NAT)))) return -EINVAL; } rth = dst_alloc(sizeof(struct rtable), &ipv4_dst_ops); if (!rth) return -ENOBUFS; rth->u.dst.output= ip_rt_bug; rth->u.dst.use = 1; rth->key.dst = dst_key; rth->rt_dst = dst_key; rth->rt_dst_map = daddr; rth->key.tos = tos; rth->key.src = src_key; rth->rt_src = src_key; rth->rt_src_map = saddr; rth->rt_src_dev = dev; rth->key.src_dev= pdev; rth->u.dst.dev = devout; rth->key.dst_dev= NULL; rth->rt_gateway = daddr; rth->rt_spec_dst= daddr; if (!(flags&RTF_REJECT)) { if (flags&RTF_LOCAL) rth->u.dst.input= ip_local_deliver; if (!(flags&(RTF_NOFORWARD|RTF_BROADCAST))) { if (flags&RTF_MULTICAST) { #ifdef CONFIG_IP_MROUTE if (!LOCAL_MCAST(daddr) && ipv4_config.multicast_route) { rth->u.dst.input = ip_mr_input; rth->u.dst.output = ip_output; } #endif } else if (!(flags&RTF_LOCAL)) { rth->u.dst.input = ip_forward; rth->u.dst.output = ip_output; } } } else if (IS_ROUTER && !(flags&(RTF_MULTICAST|RTF_BROADCAST))) { rth->u.dst.input= ip_error; rth->u.dst.error= -err; } if ((flags&(RTF_BROADCAST|RTF_MULTICAST)) || !(flags&RTF_LOCAL)) rth->rt_spec_dst= dev->pa_addr; if (fi) { rth->u.dst.pmtu = fi->fib_mtu; rth->u.dst.window=fi->fib_window; rth->u.dst.rtt = fi->fib_irtt; if (flags & RTF_GATEWAY) rth->rt_gateway = fi->fib_gateway; } else { rth->u.dst.pmtu = devout->mtu; rth->u.dst.window=0; rth->u.dst.rtt = TCP_TIMEOUT_INIT; } if (!(flags&(RTF_LOCAL|RTF_BROADCAST|RTF_MULTICAST|RTCF_NAT)) && flags&RTCF_DIRECTSRC && (devout == dev || (ipv4_config.rfc1620_redirects && net_alias_main_dev(devout) == pdev))) flags |= RTCF_DOREDIRECT; rth->rt_flags = flags; if (log) printk(KERN_INFO "installing route %08lX -> %08lX\n", ntohl(rth->rt_src), ntohl(rth->rt_dst)); if (flags&(RTF_LOCAL|RTF_MULTICAST|RTF_BROADCAST|RTF_REJECT)) { skb->dst = (struct dst_entry*)rt_intern_hash(hash, rth, 0); return 0; } skb->dst = (struct dst_entry*)rt_intern_hash(hash, rth, __constant_ntohs(skb->protocol)); return 0; mc_input: if (skb->protocol != __constant_htons(ETH_P_IP)) return -EINVAL; if (ZERONET(saddr)) { if (!ipv4_config.bootp_agent) goto martian_source; flags |= RTF_NOFORWARD|RTF_LOCAL; } else { src_fi = fib_lookup_info(saddr, 0, tos, &loopback_dev, NULL); if (!src_fi) goto martian_source; if (src_fi->fib_flags&(RTF_LOCAL|RTF_BROADCAST|RTF_MULTICAST|RTF_NAT)) goto martian_source; if (!(src_fi->fib_flags&RTF_GATEWAY)) flags |= RTCF_DIRECTSRC; if (!MULTICAST(daddr) || !ipv4_config.multicast_route || LOCAL_MCAST(daddr)) { if (net_alias_main_dev(src_fi->fib_dev) == pdev) { skb->dev = dev = src_fi->fib_dev; } else { /* Fascist not-unicast filtering 8) */ goto martian_source; } } } if (!MULTICAST(daddr)) { flags |= RTF_LOCAL|RTF_BROADCAST|RTF_NOFORWARD; devout = dev; goto make_route; } flags |= RTF_MULTICAST|RTF_LOCAL; if (ip_check_mc(dev, daddr) == 0) { flags &= ~RTF_LOCAL; if (!ipv4_config.multicast_route || !(dev->flags&IFF_ALLMULTI)) goto no_route; } devout = dev; goto make_route; promisc_ip: flags |= RTF_LOCAL|RTF_NOFORWARD; if (MULTICAST(daddr)) flags |= RTF_MULTICAST; else flags |= RTF_BROADCAST; devout = dev; goto make_route; no_route: flags |= RTF_REJECT; devout = dev; goto make_route; /* * Do not cache martian addresses: they should be logged (RFC1812) */ martian_destination: if (ipv4_config.log_martians) printk(KERN_WARNING "martian destination %08x from %08x, dev %s\n", daddr, saddr, dev->name); return -EINVAL; martian_source: if (ipv4_config.log_martians) { /* * RFC1812 recommenadtion, if source is martian, * the only hint is MAC header. */ printk(KERN_WARNING "martian source %08x for %08x, dev %s\n", saddr, daddr, dev->name); if (dev->hard_header_len) { int i; unsigned char *p = skb->mac.raw; printk(KERN_WARNING "ll header:"); for (i=0; i<dev->hard_header_len; i++, p++) printk(" %02x", *p); printk("\n"); } } return -EINVAL; } int ip_route_input(struct sk_buff *skb, u32 daddr, u32 saddr, u8 tos, struct device *dev) { struct rtable * rth; unsigned hash; if (skb->dst) return 0; #if RT_CACHE_DEBUG >= 1 if (dev->flags & IFF_LOOPBACK) { printk(KERN_DEBUG "ip_route_input: bug: packet is looped back\n"); return -EINVAL; } if (net_alias_main_dev(dev) != dev) printk(KERN_DEBUG "ip_route_input: bug: packet is received on alias %s\n", dev->name); #endif tos &= IPTOS_TOS_MASK; hash = rt_hash_code(daddr, saddr^(unsigned long)dev, tos); skb->dev = dev; for (rth=rt_hash_table[hash]; rth; rth=rth->u.rt_next) { if (rth->key.dst == daddr && rth->key.src == saddr && rth->key.src_dev == dev && rth->key.dst_dev == NULL && rth->key.tos == tos) { rth->u.dst.lastuse = jiffies; atomic_inc(&rth->u.dst.use); atomic_inc(&rth->u.dst.refcnt); skb->dst = (struct dst_entry*)rth; skb->dev = rth->rt_src_dev; return 0; } } return ip_route_input_slow(skb, daddr, saddr, tos, dev); } /* * Major route resolver routine. */ int ip_route_output_slow(struct rtable **rp, u32 daddr, u32 saddr, u8 tos, struct device *dev_out) { u32 src_key = saddr; u32 dst_key = daddr; u32 dst_map; struct device *dst_dev_key = dev_out; unsigned flags = 0; struct fib_info *fi = NULL; struct rtable *rth; #ifdef CONFIG_IP_LOCAL_RT_POLICY struct fib_result res; #endif unsigned hash; tos &= IPTOS_TOS_MASK|1; if (saddr) { if (MULTICAST(saddr) || BADCLASS(saddr) || ZERONET(saddr) || __ip_chk_addr(saddr) != IS_MYADDR) return -EINVAL; if (dev_out == NULL && (MULTICAST(daddr) || daddr == 0xFFFFFFFF)) dev_out = ip_dev_find(saddr, NULL); } if (!daddr) daddr = saddr; if (dev_out) { if (!saddr) { saddr = dev_out->pa_addr; if (!daddr) daddr = saddr; } dst_map = daddr; if (MULTICAST(daddr) || daddr == 0xFFFFFFFF) goto make_route; } if (!daddr) daddr = htonl(INADDR_LOOPBACK); #ifdef CONFIG_IP_LOCAL_RT_POLICY if (fib_lookup(&res, daddr, saddr, tos, &loopback_dev, dev_out)) return -ENETUNREACH; fi = res.f->fib_info; dst_map = daddr; if (fi->fib_flags&RTF_NAT) return -EINVAL; if (!saddr) { saddr = fi->fib_dev->pa_addr; /* * "Stabilization" of route. * This step is necessary, if locally originated packets * are subjected to source routing, else we could get * route flapping. */ fi = fib_lookup_info(dst_map, saddr, tos, &loopback_dev, dev_out); if (!fi) return -ENETUNREACH; } #else fi = fib_lookup_info(daddr, 0, tos, &loopback_dev, dev_out); if (!fi) return -ENETUNREACH; if (fi->fib_flags&RTF_NAT) return -EINVAL; dst_map = daddr; if (!saddr) saddr = fi->fib_dev->pa_addr; #endif flags |= fi->fib_flags; dev_out = fi->fib_dev; if (RT_LOCALADDR(flags)) { dev_out = &loopback_dev; fi = NULL; } if (dst_dev_key && dev_out != dst_dev_key) return -EINVAL; make_route: if (LOOPBACK(saddr) && !(dev_out->flags&IFF_LOOPBACK)) { printk(KERN_DEBUG "this guy talks to %08x from loopback\n", daddr); return -EINVAL; } if (daddr == 0xFFFFFFFF) flags |= RTF_BROADCAST; else if (MULTICAST(daddr)) flags |= RTF_MULTICAST; else if (BADCLASS(daddr) || ZERONET(daddr)) return -EINVAL; if (flags&RTF_BROADCAST && (dev_out->flags&IFF_LOOPBACK || !(dev_out->flags&IFF_BROADCAST))) flags &= ~RTF_LOCAL; else if (flags&RTF_MULTICAST) { if (ip_check_mc(dev_out, daddr)) flags |= RTF_LOCAL; } rth = dst_alloc(sizeof(struct rtable), &ipv4_dst_ops); if (!rth) return -ENOBUFS; rth->u.dst.use = 1; rth->key.dst = dst_key; rth->key.tos = tos; rth->key.src = src_key; rth->key.src_dev= NULL; rth->key.dst_dev= dst_dev_key; rth->rt_dst = daddr; rth->rt_dst_map = dst_map; rth->rt_src = saddr; rth->rt_src_map = saddr; rth->rt_src_dev = dev_out; rth->u.dst.dev = dev_out; rth->rt_gateway = dst_map; rth->rt_spec_dst= dev_out->pa_addr; rth->u.dst.output=ip_output; if (flags&RTF_LOCAL) { rth->u.dst.input = ip_local_deliver; rth->rt_spec_dst = daddr; } if (flags&(RTF_BROADCAST|RTF_MULTICAST)) { rth->rt_spec_dst = dev_out->pa_addr; flags &= ~RTF_GATEWAY; if (flags&RTF_LOCAL) rth->u.dst.output = ip_mc_output; if (flags&RTF_MULTICAST) { if (dev_out->flags&IFF_ALLMULTI) rth->u.dst.output = ip_mc_output; #ifdef CONFIG_IP_MROUTE if (ipv4_config.multicast_route && !LOCAL_MCAST(daddr)) rth->u.dst.input = ip_mr_input; #endif } } if (fi) { if (flags&RTF_GATEWAY) rth->rt_gateway = fi->fib_gateway; rth->u.dst.pmtu = fi->fib_mtu; rth->u.dst.window=fi->fib_window; rth->u.dst.rtt = fi->fib_irtt; } else { rth->u.dst.pmtu = dev_out->mtu; rth->u.dst.window=0; rth->u.dst.rtt = TCP_TIMEOUT_INIT; } rth->rt_flags = flags; hash = rt_hash_code(dst_key, dst_dev_key ? src_key^(dst_dev_key->ifindex<<5) : src_key, tos); *rp = rt_intern_hash(hash, rth, ETH_P_IP); return 0; } int ip_route_output(struct rtable **rp, u32 daddr, u32 saddr, u8 tos, struct device *dev_out) { unsigned hash; struct rtable *rth; hash = rt_hash_code(daddr, dev_out ? saddr^(dev_out->ifindex<<5) : saddr, tos); start_bh_atomic(); for (rth=rt_hash_table[hash]; rth; rth=rth->u.rt_next) { if (rth->key.dst == daddr && rth->key.src == saddr && rth->key.src_dev == NULL && rth->key.dst_dev == dev_out && rth->key.tos == tos) { rth->u.dst.lastuse = jiffies; atomic_inc(&rth->u.dst.use); atomic_inc(&rth->u.dst.refcnt); end_bh_atomic(); *rp = rth; return 0; } } end_bh_atomic(); return ip_route_output_slow(rp, daddr, saddr, tos, dev_out); } int ip_route_output_dev(struct rtable **rp, u32 daddr, u32 saddr, u8 tos, int ifindex) { unsigned hash; struct rtable *rth; struct device *dev_out; hash = rt_hash_code(daddr, saddr^(ifindex<<5), tos); start_bh_atomic(); for (rth=rt_hash_table[hash]; rth; rth=rth->u.rt_next) { if (rth->key.dst == daddr && rth->key.src == saddr && rth->key.src_dev == NULL && rth->key.tos == tos && rth->key.dst_dev && rth->key.dst_dev->ifindex == ifindex) { rth->u.dst.lastuse = jiffies; atomic_inc(&rth->u.dst.use); atomic_inc(&rth->u.dst.refcnt); end_bh_atomic(); *rp = rth; return 0; } } end_bh_atomic(); dev_out = dev_get_by_index(ifindex); if (!dev_out) return -ENODEV; return ip_route_output_slow(rp, daddr, saddr, tos, dev_out); } void ip_rt_multicast_event(struct device *dev) { rt_cache_flush(0); } void ip_rt_init() { ip_fib_init(); #ifdef CONFIG_PROC_FS proc_net_register(&(struct proc_dir_entry) { PROC_NET_RTCACHE, 8, "rt_cache", S_IFREG | S_IRUGO, 1, 0, 0, 0, &proc_net_inode_operations, rt_cache_get_info }); #endif } |