/* * 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. * * IPv4 Forwarding Information Base: semantics. * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * * 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 <asm/uaccess.h> #include <asm/system.h> #include <linux/bitops.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/jiffies.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/inetdevice.h> #include <linux/netdevice.h> #include <linux/if_arp.h> #include <linux/proc_fs.h> #include <linux/skbuff.h> #include <linux/init.h> #include <linux/slab.h> #include <net/arp.h> #include <net/ip.h> #include <net/protocol.h> #include <net/route.h> #include <net/tcp.h> #include <net/sock.h> #include <net/ip_fib.h> #include <net/netlink.h> #include <net/nexthop.h> #include "fib_lookup.h" static DEFINE_SPINLOCK(fib_info_lock); static struct hlist_head *fib_info_hash; static struct hlist_head *fib_info_laddrhash; static unsigned int fib_hash_size; static unsigned int fib_info_cnt; #define DEVINDEX_HASHBITS 8 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS) static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE]; #ifdef CONFIG_IP_ROUTE_MULTIPATH static DEFINE_SPINLOCK(fib_multipath_lock); #define for_nexthops(fi) { \ int nhsel; const struct fib_nh *nh; \ for (nhsel = 0, nh = (fi)->fib_nh; \ nhsel < (fi)->fib_nhs; \ nh++, nhsel++) #define change_nexthops(fi) { \ int nhsel; struct fib_nh *nexthop_nh; \ for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ nhsel < (fi)->fib_nhs; \ nexthop_nh++, nhsel++) #else /* CONFIG_IP_ROUTE_MULTIPATH */ /* Hope, that gcc will optimize it to get rid of dummy loop */ #define for_nexthops(fi) { \ int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \ for (nhsel = 0; nhsel < 1; nhsel++) #define change_nexthops(fi) { \ int nhsel; \ struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \ for (nhsel = 0; nhsel < 1; nhsel++) #endif /* CONFIG_IP_ROUTE_MULTIPATH */ #define endfor_nexthops(fi) } static const struct { int error; u8 scope; } fib_props[RTN_MAX + 1] = { [RTN_UNSPEC] = { .error = 0, .scope = RT_SCOPE_NOWHERE, }, [RTN_UNICAST] = { .error = 0, .scope = RT_SCOPE_UNIVERSE, }, [RTN_LOCAL] = { .error = 0, .scope = RT_SCOPE_HOST, }, [RTN_BROADCAST] = { .error = 0, .scope = RT_SCOPE_LINK, }, [RTN_ANYCAST] = { .error = 0, .scope = RT_SCOPE_LINK, }, [RTN_MULTICAST] = { .error = 0, .scope = RT_SCOPE_UNIVERSE, }, [RTN_BLACKHOLE] = { .error = -EINVAL, .scope = RT_SCOPE_UNIVERSE, }, [RTN_UNREACHABLE] = { .error = -EHOSTUNREACH, .scope = RT_SCOPE_UNIVERSE, }, [RTN_PROHIBIT] = { .error = -EACCES, .scope = RT_SCOPE_UNIVERSE, }, [RTN_THROW] = { .error = -EAGAIN, .scope = RT_SCOPE_UNIVERSE, }, [RTN_NAT] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE, }, [RTN_XRESOLVE] = { .error = -EINVAL, .scope = RT_SCOPE_NOWHERE, }, }; /* Release a nexthop info record */ static void free_fib_info_rcu(struct rcu_head *head) { struct fib_info *fi = container_of(head, struct fib_info, rcu); kfree(fi); } void free_fib_info(struct fib_info *fi) { if (fi->fib_dead == 0) { pr_warning("Freeing alive fib_info %p\n", fi); return; } change_nexthops(fi) { if (nexthop_nh->nh_dev) dev_put(nexthop_nh->nh_dev); nexthop_nh->nh_dev = NULL; } endfor_nexthops(fi); fib_info_cnt--; release_net(fi->fib_net); call_rcu(&fi->rcu, free_fib_info_rcu); } void fib_release_info(struct fib_info *fi) { spin_lock_bh(&fib_info_lock); if (fi && --fi->fib_treeref == 0) { hlist_del(&fi->fib_hash); if (fi->fib_prefsrc) hlist_del(&fi->fib_lhash); change_nexthops(fi) { if (!nexthop_nh->nh_dev) continue; hlist_del(&nexthop_nh->nh_hash); } endfor_nexthops(fi) fi->fib_dead = 1; fib_info_put(fi); } spin_unlock_bh(&fib_info_lock); } static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi) { const struct fib_nh *onh = ofi->fib_nh; for_nexthops(fi) { if (nh->nh_oif != onh->nh_oif || nh->nh_gw != onh->nh_gw || nh->nh_scope != onh->nh_scope || #ifdef CONFIG_IP_ROUTE_MULTIPATH nh->nh_weight != onh->nh_weight || #endif #ifdef CONFIG_NET_CLS_ROUTE nh->nh_tclassid != onh->nh_tclassid || #endif ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD)) return -1; onh++; } endfor_nexthops(fi); return 0; } static inline unsigned int fib_devindex_hashfn(unsigned int val) { unsigned int mask = DEVINDEX_HASHSIZE - 1; return (val ^ (val >> DEVINDEX_HASHBITS) ^ (val >> (DEVINDEX_HASHBITS * 2))) & mask; } static inline unsigned int fib_info_hashfn(const struct fib_info *fi) { unsigned int mask = (fib_hash_size - 1); unsigned int val = fi->fib_nhs; val ^= fi->fib_protocol; val ^= (__force u32)fi->fib_prefsrc; val ^= fi->fib_priority; for_nexthops(fi) { val ^= fib_devindex_hashfn(nh->nh_oif); } endfor_nexthops(fi) return (val ^ (val >> 7) ^ (val >> 12)) & mask; } static struct fib_info *fib_find_info(const struct fib_info *nfi) { struct hlist_head *head; struct hlist_node *node; struct fib_info *fi; unsigned int hash; hash = fib_info_hashfn(nfi); head = &fib_info_hash[hash]; hlist_for_each_entry(fi, node, head, fib_hash) { if (!net_eq(fi->fib_net, nfi->fib_net)) continue; if (fi->fib_nhs != nfi->fib_nhs) continue; if (nfi->fib_protocol == fi->fib_protocol && nfi->fib_prefsrc == fi->fib_prefsrc && nfi->fib_priority == fi->fib_priority && memcmp(nfi->fib_metrics, fi->fib_metrics, sizeof(fi->fib_metrics)) == 0 && ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 && (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0)) return fi; } return NULL; } /* Check, that the gateway is already configured. * Used only by redirect accept routine. */ int ip_fib_check_default(__be32 gw, struct net_device *dev) { struct hlist_head *head; struct hlist_node *node; struct fib_nh *nh; unsigned int hash; spin_lock(&fib_info_lock); hash = fib_devindex_hashfn(dev->ifindex); head = &fib_info_devhash[hash]; hlist_for_each_entry(nh, node, head, nh_hash) { if (nh->nh_dev == dev && nh->nh_gw == gw && !(nh->nh_flags & RTNH_F_DEAD)) { spin_unlock(&fib_info_lock); return 0; } } spin_unlock(&fib_info_lock); return -1; } static inline size_t fib_nlmsg_size(struct fib_info *fi) { size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg)) + nla_total_size(4) /* RTA_TABLE */ + nla_total_size(4) /* RTA_DST */ + nla_total_size(4) /* RTA_PRIORITY */ + nla_total_size(4); /* RTA_PREFSRC */ /* space for nested metrics */ payload += nla_total_size((RTAX_MAX * nla_total_size(4))); if (fi->fib_nhs) { /* Also handles the special case fib_nhs == 1 */ /* each nexthop is packed in an attribute */ size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); /* may contain flow and gateway attribute */ nhsize += 2 * nla_total_size(4); /* all nexthops are packed in a nested attribute */ payload += nla_total_size(fi->fib_nhs * nhsize); } return payload; } void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, int dst_len, u32 tb_id, struct nl_info *info, unsigned int nlm_flags) { struct sk_buff *skb; u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; int err = -ENOBUFS; skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL); if (skb == NULL) goto errout; err = fib_dump_info(skb, info->pid, seq, event, tb_id, fa->fa_type, fa->fa_scope, key, dst_len, fa->fa_tos, fa->fa_info, nlm_flags); if (err < 0) { /* -EMSGSIZE implies BUG in fib_nlmsg_size() */ WARN_ON(err == -EMSGSIZE); kfree_skb(skb); goto errout; } rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE, info->nlh, GFP_KERNEL); return; errout: if (err < 0) rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); } /* Return the first fib alias matching TOS with * priority less than or equal to PRIO. */ struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio) { if (fah) { struct fib_alias *fa; list_for_each_entry(fa, fah, fa_list) { if (fa->fa_tos > tos) continue; if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos) return fa; } } return NULL; } int fib_detect_death(struct fib_info *fi, int order, struct fib_info **last_resort, int *last_idx, int dflt) { struct neighbour *n; int state = NUD_NONE; n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev); if (n) { state = n->nud_state; neigh_release(n); } if (state == NUD_REACHABLE) return 0; if ((state & NUD_VALID) && order != dflt) return 0; if ((state & NUD_VALID) || (*last_idx < 0 && order > dflt)) { *last_resort = fi; *last_idx = order; } return 1; } #ifdef CONFIG_IP_ROUTE_MULTIPATH static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining) { int nhs = 0; while (rtnh_ok(rtnh, remaining)) { nhs++; rtnh = rtnh_next(rtnh, &remaining); } /* leftover implies invalid nexthop configuration, discard it */ return remaining > 0 ? 0 : nhs; } static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, int remaining, struct fib_config *cfg) { change_nexthops(fi) { int attrlen; if (!rtnh_ok(rtnh, remaining)) return -EINVAL; nexthop_nh->nh_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; nexthop_nh->nh_oif = rtnh->rtnh_ifindex; nexthop_nh->nh_weight = rtnh->rtnh_hops + 1; attrlen = rtnh_attrlen(rtnh); if (attrlen > 0) { struct nlattr *nla, *attrs = rtnh_attrs(rtnh); nla = nla_find(attrs, attrlen, RTA_GATEWAY); nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0; #ifdef CONFIG_NET_CLS_ROUTE nla = nla_find(attrs, attrlen, RTA_FLOW); nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0; #endif } rtnh = rtnh_next(rtnh, &remaining); } endfor_nexthops(fi); return 0; } #endif int fib_nh_match(struct fib_config *cfg, struct fib_info *fi) { #ifdef CONFIG_IP_ROUTE_MULTIPATH struct rtnexthop *rtnh; int remaining; #endif if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority) return 1; if (cfg->fc_oif || cfg->fc_gw) { if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) && (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw)) return 0; return 1; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (cfg->fc_mp == NULL) return 0; rtnh = cfg->fc_mp; remaining = cfg->fc_mp_len; for_nexthops(fi) { int attrlen; if (!rtnh_ok(rtnh, remaining)) return -EINVAL; if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif) return 1; attrlen = rtnh_attrlen(rtnh); if (attrlen < 0) { struct nlattr *nla, *attrs = rtnh_attrs(rtnh); nla = nla_find(attrs, attrlen, RTA_GATEWAY); if (nla && nla_get_be32(nla) != nh->nh_gw) return 1; #ifdef CONFIG_NET_CLS_ROUTE nla = nla_find(attrs, attrlen, RTA_FLOW); if (nla && nla_get_u32(nla) != nh->nh_tclassid) return 1; #endif } rtnh = rtnh_next(rtnh, &remaining); } endfor_nexthops(fi); #endif return 0; } /* * Picture * ------- * * Semantics of nexthop is very messy by historical reasons. * We have to take into account, that: * a) gateway can be actually local interface address, * so that gatewayed route is direct. * b) gateway must be on-link address, possibly * described not by an ifaddr, but also by a direct route. * c) If both gateway and interface are specified, they should not * contradict. * d) If we use tunnel routes, gateway could be not on-link. * * Attempt to reconcile all of these (alas, self-contradictory) conditions * results in pretty ugly and hairy code with obscure logic. * * I chose to generalized it instead, so that the size * of code does not increase practically, but it becomes * much more general. * Every prefix is assigned a "scope" value: "host" is local address, * "link" is direct route, * [ ... "site" ... "interior" ... ] * and "universe" is true gateway route with global meaning. * * Every prefix refers to a set of "nexthop"s (gw, oif), * where gw must have narrower scope. This recursion stops * when gw has LOCAL scope or if "nexthop" is declared ONLINK, * which means that gw is forced to be on link. * * Code is still hairy, but now it is apparently logically * consistent and very flexible. F.e. as by-product it allows * to co-exists in peace independent exterior and interior * routing processes. * * Normally it looks as following. * * {universe prefix} -> (gw, oif) [scope link] * | * |-> {link prefix} -> (gw, oif) [scope local] * | * |-> {local prefix} (terminal node) */ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, struct fib_nh *nh) { int err; struct net *net; struct net_device *dev; net = cfg->fc_nlinfo.nl_net; if (nh->nh_gw) { struct fib_result res; if (nh->nh_flags & RTNH_F_ONLINK) { if (cfg->fc_scope >= RT_SCOPE_LINK) return -EINVAL; if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST) return -EINVAL; dev = __dev_get_by_index(net, nh->nh_oif); if (!dev) return -ENODEV; if (!(dev->flags & IFF_UP)) return -ENETDOWN; nh->nh_dev = dev; dev_hold(dev); nh->nh_scope = RT_SCOPE_LINK; return 0; } rcu_read_lock(); { struct flowi fl = { .fl4_dst = nh->nh_gw, .fl4_scope = cfg->fc_scope + 1, .oif = nh->nh_oif, }; /* It is not necessary, but requires a bit of thinking */ if (fl.fl4_scope < RT_SCOPE_LINK) fl.fl4_scope = RT_SCOPE_LINK; err = fib_lookup(net, &fl, &res); if (err) { rcu_read_unlock(); return err; } } err = -EINVAL; if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) goto out; nh->nh_scope = res.scope; nh->nh_oif = FIB_RES_OIF(res); nh->nh_dev = dev = FIB_RES_DEV(res); if (!dev) goto out; dev_hold(dev); err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; } else { struct in_device *in_dev; if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) return -EINVAL; rcu_read_lock(); err = -ENODEV; in_dev = inetdev_by_index(net, nh->nh_oif); if (in_dev == NULL) goto out; err = -ENETDOWN; if (!(in_dev->dev->flags & IFF_UP)) goto out; nh->nh_dev = in_dev->dev; dev_hold(nh->nh_dev); nh->nh_scope = RT_SCOPE_HOST; err = 0; } out: rcu_read_unlock(); return err; } static inline unsigned int fib_laddr_hashfn(__be32 val) { unsigned int mask = (fib_hash_size - 1); return ((__force u32)val ^ ((__force u32)val >> 7) ^ ((__force u32)val >> 14)) & mask; } static struct hlist_head *fib_hash_alloc(int bytes) { if (bytes <= PAGE_SIZE) return kzalloc(bytes, GFP_KERNEL); else return (struct hlist_head *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(bytes)); } static void fib_hash_free(struct hlist_head *hash, int bytes) { if (!hash) return; if (bytes <= PAGE_SIZE) kfree(hash); else free_pages((unsigned long) hash, get_order(bytes)); } static void fib_hash_move(struct hlist_head *new_info_hash, struct hlist_head *new_laddrhash, unsigned int new_size) { struct hlist_head *old_info_hash, *old_laddrhash; unsigned int old_size = fib_hash_size; unsigned int i, bytes; spin_lock_bh(&fib_info_lock); old_info_hash = fib_info_hash; old_laddrhash = fib_info_laddrhash; fib_hash_size = new_size; for (i = 0; i < old_size; i++) { struct hlist_head *head = &fib_info_hash[i]; struct hlist_node *node, *n; struct fib_info *fi; hlist_for_each_entry_safe(fi, node, n, head, fib_hash) { struct hlist_head *dest; unsigned int new_hash; hlist_del(&fi->fib_hash); new_hash = fib_info_hashfn(fi); dest = &new_info_hash[new_hash]; hlist_add_head(&fi->fib_hash, dest); } } fib_info_hash = new_info_hash; for (i = 0; i < old_size; i++) { struct hlist_head *lhead = &fib_info_laddrhash[i]; struct hlist_node *node, *n; struct fib_info *fi; hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) { struct hlist_head *ldest; unsigned int new_hash; hlist_del(&fi->fib_lhash); new_hash = fib_laddr_hashfn(fi->fib_prefsrc); ldest = &new_laddrhash[new_hash]; hlist_add_head(&fi->fib_lhash, ldest); } } fib_info_laddrhash = new_laddrhash; spin_unlock_bh(&fib_info_lock); bytes = old_size * sizeof(struct hlist_head *); fib_hash_free(old_info_hash, bytes); fib_hash_free(old_laddrhash, bytes); } struct fib_info *fib_create_info(struct fib_config *cfg) { int err; struct fib_info *fi = NULL; struct fib_info *ofi; int nhs = 1; struct net *net = cfg->fc_nlinfo.nl_net; /* Fast check to catch the most weird cases */ if (fib_props[cfg->fc_type].scope > cfg->fc_scope) goto err_inval; #ifdef CONFIG_IP_ROUTE_MULTIPATH if (cfg->fc_mp) { nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len); if (nhs == 0) goto err_inval; } #endif err = -ENOBUFS; if (fib_info_cnt >= fib_hash_size) { unsigned int new_size = fib_hash_size << 1; struct hlist_head *new_info_hash; struct hlist_head *new_laddrhash; unsigned int bytes; if (!new_size) new_size = 1; bytes = new_size * sizeof(struct hlist_head *); new_info_hash = fib_hash_alloc(bytes); new_laddrhash = fib_hash_alloc(bytes); if (!new_info_hash || !new_laddrhash) { fib_hash_free(new_info_hash, bytes); fib_hash_free(new_laddrhash, bytes); } else fib_hash_move(new_info_hash, new_laddrhash, new_size); if (!fib_hash_size) goto failure; } fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL); if (fi == NULL) goto failure; fib_info_cnt++; fi->fib_net = hold_net(net); fi->fib_protocol = cfg->fc_protocol; fi->fib_flags = cfg->fc_flags; fi->fib_priority = cfg->fc_priority; fi->fib_prefsrc = cfg->fc_prefsrc; fi->fib_nhs = nhs; change_nexthops(fi) { nexthop_nh->nh_parent = fi; } endfor_nexthops(fi) if (cfg->fc_mx) { struct nlattr *nla; int remaining; nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { int type = nla_type(nla); if (type) { if (type > RTAX_MAX) goto err_inval; fi->fib_metrics[type - 1] = nla_get_u32(nla); } } } if (cfg->fc_mp) { #ifdef CONFIG_IP_ROUTE_MULTIPATH err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg); if (err != 0) goto failure; if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) goto err_inval; if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) goto err_inval; #ifdef CONFIG_NET_CLS_ROUTE if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) goto err_inval; #endif #else goto err_inval; #endif } else { struct fib_nh *nh = fi->fib_nh; nh->nh_oif = cfg->fc_oif; nh->nh_gw = cfg->fc_gw; nh->nh_flags = cfg->fc_flags; #ifdef CONFIG_NET_CLS_ROUTE nh->nh_tclassid = cfg->fc_flow; #endif #ifdef CONFIG_IP_ROUTE_MULTIPATH nh->nh_weight = 1; #endif } if (fib_props[cfg->fc_type].error) { if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) goto err_inval; goto link_it; } if (cfg->fc_scope > RT_SCOPE_HOST) goto err_inval; if (cfg->fc_scope == RT_SCOPE_HOST) { struct fib_nh *nh = fi->fib_nh; /* Local address is added. */ if (nhs != 1 || nh->nh_gw) goto err_inval; nh->nh_scope = RT_SCOPE_NOWHERE; nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif); err = -ENODEV; if (nh->nh_dev == NULL) goto failure; } else { change_nexthops(fi) { err = fib_check_nh(cfg, fi, nexthop_nh); if (err != 0) goto failure; } endfor_nexthops(fi) } if (fi->fib_prefsrc) { if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || fi->fib_prefsrc != cfg->fc_dst) if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL) goto err_inval; } link_it: ofi = fib_find_info(fi); if (ofi) { fi->fib_dead = 1; free_fib_info(fi); ofi->fib_treeref++; return ofi; } fi->fib_treeref++; atomic_inc(&fi->fib_clntref); spin_lock_bh(&fib_info_lock); hlist_add_head(&fi->fib_hash, &fib_info_hash[fib_info_hashfn(fi)]); if (fi->fib_prefsrc) { struct hlist_head *head; head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)]; hlist_add_head(&fi->fib_lhash, head); } change_nexthops(fi) { struct hlist_head *head; unsigned int hash; if (!nexthop_nh->nh_dev) continue; hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex); head = &fib_info_devhash[hash]; hlist_add_head(&nexthop_nh->nh_hash, head); } endfor_nexthops(fi) spin_unlock_bh(&fib_info_lock); return fi; err_inval: err = -EINVAL; failure: if (fi) { fi->fib_dead = 1; free_fib_info(fi); } return ERR_PTR(err); } /* Note! fib_semantic_match intentionally uses RCU list functions. */ int fib_semantic_match(struct list_head *head, const struct flowi *flp, struct fib_result *res, int prefixlen, int fib_flags) { struct fib_alias *fa; int nh_sel = 0; list_for_each_entry_rcu(fa, head, fa_list) { int err; if (fa->fa_tos && fa->fa_tos != flp->fl4_tos) continue; if (fa->fa_scope < flp->fl4_scope) continue; fib_alias_accessed(fa); err = fib_props[fa->fa_type].error; if (err == 0) { struct fib_info *fi = fa->fa_info; if (fi->fib_flags & RTNH_F_DEAD) continue; switch (fa->fa_type) { case RTN_UNICAST: case RTN_LOCAL: case RTN_BROADCAST: case RTN_ANYCAST: case RTN_MULTICAST: for_nexthops(fi) { if (nh->nh_flags & RTNH_F_DEAD) continue; if (!flp->oif || flp->oif == nh->nh_oif) break; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (nhsel < fi->fib_nhs) { nh_sel = nhsel; goto out_fill_res; } #else if (nhsel < 1) goto out_fill_res; #endif endfor_nexthops(fi); continue; default: pr_warning("fib_semantic_match bad type %#x\n", fa->fa_type); return -EINVAL; } } return err; } return 1; out_fill_res: res->prefixlen = prefixlen; res->nh_sel = nh_sel; res->type = fa->fa_type; res->scope = fa->fa_scope; res->fi = fa->fa_info; if (!(fib_flags & FIB_LOOKUP_NOREF)) atomic_inc(&res->fi->fib_clntref); return 0; } /* Find appropriate source address to this destination */ __be32 __fib_res_prefsrc(struct fib_result *res) { return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope); } int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event, u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos, struct fib_info *fi, unsigned int flags) { struct nlmsghdr *nlh; struct rtmsg *rtm; nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags); if (nlh == NULL) return -EMSGSIZE; rtm = nlmsg_data(nlh); rtm->rtm_family = AF_INET; rtm->rtm_dst_len = dst_len; rtm->rtm_src_len = 0; rtm->rtm_tos = tos; if (tb_id < 256) rtm->rtm_table = tb_id; else rtm->rtm_table = RT_TABLE_COMPAT; NLA_PUT_U32(skb, RTA_TABLE, tb_id); rtm->rtm_type = type; rtm->rtm_flags = fi->fib_flags; rtm->rtm_scope = scope; rtm->rtm_protocol = fi->fib_protocol; if (rtm->rtm_dst_len) NLA_PUT_BE32(skb, RTA_DST, dst); if (fi->fib_priority) NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority); if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0) goto nla_put_failure; if (fi->fib_prefsrc) NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc); if (fi->fib_nhs == 1) { if (fi->fib_nh->nh_gw) NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw); if (fi->fib_nh->nh_oif) NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif); #ifdef CONFIG_NET_CLS_ROUTE if (fi->fib_nh[0].nh_tclassid) NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid); #endif } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (fi->fib_nhs > 1) { struct rtnexthop *rtnh; struct nlattr *mp; mp = nla_nest_start(skb, RTA_MULTIPATH); if (mp == NULL) goto nla_put_failure; for_nexthops(fi) { rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); if (rtnh == NULL) goto nla_put_failure; rtnh->rtnh_flags = nh->nh_flags & 0xFF; rtnh->rtnh_hops = nh->nh_weight - 1; rtnh->rtnh_ifindex = nh->nh_oif; if (nh->nh_gw) NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw); #ifdef CONFIG_NET_CLS_ROUTE if (nh->nh_tclassid) NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid); #endif /* length of rtnetlink header + attributes */ rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh; } endfor_nexthops(fi); nla_nest_end(skb, mp); } #endif return nlmsg_end(skb, nlh); nla_put_failure: nlmsg_cancel(skb, nlh); return -EMSGSIZE; } /* * Update FIB if: * - local address disappeared -> we must delete all the entries * referring to it. * - device went down -> we must shutdown all nexthops going via it. */ int fib_sync_down_addr(struct net *net, __be32 local) { int ret = 0; unsigned int hash = fib_laddr_hashfn(local); struct hlist_head *head = &fib_info_laddrhash[hash]; struct hlist_node *node; struct fib_info *fi; if (fib_info_laddrhash == NULL || local == 0) return 0; hlist_for_each_entry(fi, node, head, fib_lhash) { if (!net_eq(fi->fib_net, net)) continue; if (fi->fib_prefsrc == local) { fi->fib_flags |= RTNH_F_DEAD; ret++; } } return ret; } int fib_sync_down_dev(struct net_device *dev, int force) { int ret = 0; int scope = RT_SCOPE_NOWHERE; struct fib_info *prev_fi = NULL; unsigned int hash = fib_devindex_hashfn(dev->ifindex); struct hlist_head *head = &fib_info_devhash[hash]; struct hlist_node *node; struct fib_nh *nh; if (force) scope = -1; hlist_for_each_entry(nh, node, head, nh_hash) { struct fib_info *fi = nh->nh_parent; int dead; BUG_ON(!fi->fib_nhs); if (nh->nh_dev != dev || fi == prev_fi) continue; prev_fi = fi; dead = 0; change_nexthops(fi) { if (nexthop_nh->nh_flags & RTNH_F_DEAD) dead++; else if (nexthop_nh->nh_dev == dev && nexthop_nh->nh_scope != scope) { nexthop_nh->nh_flags |= RTNH_F_DEAD; #ifdef CONFIG_IP_ROUTE_MULTIPATH spin_lock_bh(&fib_multipath_lock); fi->fib_power -= nexthop_nh->nh_power; nexthop_nh->nh_power = 0; spin_unlock_bh(&fib_multipath_lock); #endif dead++; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (force > 1 && nexthop_nh->nh_dev == dev) { dead = fi->fib_nhs; break; } #endif } endfor_nexthops(fi) if (dead == fi->fib_nhs) { fi->fib_flags |= RTNH_F_DEAD; ret++; } } return ret; } #ifdef CONFIG_IP_ROUTE_MULTIPATH /* * Dead device goes up. We wake up dead nexthops. * It takes sense only on multipath routes. */ int fib_sync_up(struct net_device *dev) { struct fib_info *prev_fi; unsigned int hash; struct hlist_head *head; struct hlist_node *node; struct fib_nh *nh; int ret; if (!(dev->flags & IFF_UP)) return 0; prev_fi = NULL; hash = fib_devindex_hashfn(dev->ifindex); head = &fib_info_devhash[hash]; ret = 0; hlist_for_each_entry(nh, node, head, nh_hash) { struct fib_info *fi = nh->nh_parent; int alive; BUG_ON(!fi->fib_nhs); if (nh->nh_dev != dev || fi == prev_fi) continue; prev_fi = fi; alive = 0; change_nexthops(fi) { if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { alive++; continue; } if (nexthop_nh->nh_dev == NULL || !(nexthop_nh->nh_dev->flags & IFF_UP)) continue; if (nexthop_nh->nh_dev != dev || !__in_dev_get_rtnl(dev)) continue; alive++; spin_lock_bh(&fib_multipath_lock); nexthop_nh->nh_power = 0; nexthop_nh->nh_flags &= ~RTNH_F_DEAD; spin_unlock_bh(&fib_multipath_lock); } endfor_nexthops(fi) if (alive > 0) { fi->fib_flags &= ~RTNH_F_DEAD; ret++; } } return ret; } /* * The algorithm is suboptimal, but it provides really * fair weighted route distribution. */ void fib_select_multipath(const struct flowi *flp, struct fib_result *res) { struct fib_info *fi = res->fi; int w; spin_lock_bh(&fib_multipath_lock); if (fi->fib_power <= 0) { int power = 0; change_nexthops(fi) { if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { power += nexthop_nh->nh_weight; nexthop_nh->nh_power = nexthop_nh->nh_weight; } } endfor_nexthops(fi); fi->fib_power = power; if (power <= 0) { spin_unlock_bh(&fib_multipath_lock); /* Race condition: route has just become dead. */ res->nh_sel = 0; return; } } /* w should be random number [0..fi->fib_power-1], * it is pretty bad approximation. */ w = jiffies % fi->fib_power; change_nexthops(fi) { if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) && nexthop_nh->nh_power) { w -= nexthop_nh->nh_power; if (w <= 0) { nexthop_nh->nh_power--; fi->fib_power--; res->nh_sel = nhsel; spin_unlock_bh(&fib_multipath_lock); return; } } } endfor_nexthops(fi); /* Race condition: route has just become dead. */ res->nh_sel = 0; spin_unlock_bh(&fib_multipath_lock); } #endif