// SPDX-License-Identifier: GPL-2.0-or-later /* * 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, */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "fib_lookup.h" static struct hlist_head *fib_info_hash; static struct hlist_head *fib_info_laddrhash; static unsigned int fib_info_hash_size; static unsigned int fib_info_hash_bits; static unsigned int fib_info_cnt; /* for_nexthops and change_nexthops only used when nexthop object * is not set in a fib_info. The logic within can reference fib_nh. */ #ifdef CONFIG_IP_ROUTE_MULTIPATH #define for_nexthops(fi) { \ int nhsel; const struct fib_nh *nh; \ for (nhsel = 0, nh = (fi)->fib_nh; \ nhsel < fib_info_num_path((fi)); \ 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 < fib_info_num_path((fi)); \ 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) } const struct fib_prop 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, }, }; static void rt_fibinfo_free(struct rtable __rcu **rtp) { struct rtable *rt = rcu_dereference_protected(*rtp, 1); if (!rt) return; /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); * because we waited an RCU grace period before calling * free_fib_info_rcu() */ dst_dev_put(&rt->dst); dst_release_immediate(&rt->dst); } static void free_nh_exceptions(struct fib_nh_common *nhc) { struct fnhe_hash_bucket *hash; int i; hash = rcu_dereference_protected(nhc->nhc_exceptions, 1); if (!hash) return; for (i = 0; i < FNHE_HASH_SIZE; i++) { struct fib_nh_exception *fnhe; fnhe = rcu_dereference_protected(hash[i].chain, 1); while (fnhe) { struct fib_nh_exception *next; next = rcu_dereference_protected(fnhe->fnhe_next, 1); rt_fibinfo_free(&fnhe->fnhe_rth_input); rt_fibinfo_free(&fnhe->fnhe_rth_output); kfree(fnhe); fnhe = next; } } kfree(hash); } static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) { int cpu; if (!rtp) return; for_each_possible_cpu(cpu) { struct rtable *rt; rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1); if (rt) { dst_dev_put(&rt->dst); dst_release_immediate(&rt->dst); } } free_percpu(rtp); } void fib_nh_common_release(struct fib_nh_common *nhc) { netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker); lwtstate_put(nhc->nhc_lwtstate); rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); rt_fibinfo_free(&nhc->nhc_rth_input); free_nh_exceptions(nhc); } EXPORT_SYMBOL_GPL(fib_nh_common_release); void fib_nh_release(struct net *net, struct fib_nh *fib_nh) { #ifdef CONFIG_IP_ROUTE_CLASSID if (fib_nh->nh_tclassid) atomic_dec(&net->ipv4.fib_num_tclassid_users); #endif fib_nh_common_release(&fib_nh->nh_common); } /* 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); if (fi->nh) { nexthop_put(fi->nh); } else { change_nexthops(fi) { fib_nh_release(fi->fib_net, nexthop_nh); } endfor_nexthops(fi); } ip_fib_metrics_put(fi->fib_metrics); kfree(fi); } void free_fib_info(struct fib_info *fi) { if (fi->fib_dead == 0) { pr_warn("Freeing alive fib_info %p\n", fi); return; } call_rcu_hurry(&fi->rcu, free_fib_info_rcu); } EXPORT_SYMBOL_GPL(free_fib_info); void fib_release_info(struct fib_info *fi) { ASSERT_RTNL(); if (fi && refcount_dec_and_test(&fi->fib_treeref)) { hlist_del(&fi->fib_hash); fib_info_cnt--; if (fi->fib_prefsrc) hlist_del(&fi->fib_lhash); if (fi->nh) { list_del(&fi->nh_list); } else { change_nexthops(fi) { if (!nexthop_nh->fib_nh_dev) continue; hlist_del_rcu(&nexthop_nh->nh_hash); } endfor_nexthops(fi) } /* Paired with READ_ONCE() from fib_table_lookup() */ WRITE_ONCE(fi->fib_dead, 1); fib_info_put(fi); } } static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) { const struct fib_nh *onh; if (fi->nh || ofi->nh) return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1; if (ofi->fib_nhs == 0) return 0; for_nexthops(fi) { onh = fib_info_nh(ofi, nhsel); if (nh->fib_nh_oif != onh->fib_nh_oif || nh->fib_nh_gw_family != onh->fib_nh_gw_family || nh->fib_nh_scope != onh->fib_nh_scope || #ifdef CONFIG_IP_ROUTE_MULTIPATH nh->fib_nh_weight != onh->fib_nh_weight || #endif #ifdef CONFIG_IP_ROUTE_CLASSID nh->nh_tclassid != onh->nh_tclassid || #endif lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) || ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK)) return -1; if (nh->fib_nh_gw_family == AF_INET && nh->fib_nh_gw4 != onh->fib_nh_gw4) return -1; if (nh->fib_nh_gw_family == AF_INET6 && ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6)) return -1; } endfor_nexthops(fi); return 0; } static struct hlist_head *fib_nh_head(struct net_device *dev) { return &dev->fib_nh_head; } static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope, u32 prefsrc, u32 priority) { unsigned int val = init_val; val ^= (protocol << 8) | scope; val ^= prefsrc; val ^= priority; return val; } static unsigned int fib_info_hashfn_result(const struct net *net, unsigned int val) { return hash_32(val ^ net_hash_mix(net), fib_info_hash_bits); } static inline unsigned int fib_info_hashfn(struct fib_info *fi) { unsigned int val; val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol, fi->fib_scope, (__force u32)fi->fib_prefsrc, fi->fib_priority); if (fi->nh) { val ^= fi->nh->id; } else { for_nexthops(fi) { val ^= nh->fib_nh_oif; } endfor_nexthops(fi) } return fib_info_hashfn_result(fi->fib_net, val); } /* no metrics, only nexthop id */ static struct fib_info *fib_find_info_nh(struct net *net, const struct fib_config *cfg) { struct hlist_head *head; struct fib_info *fi; unsigned int hash; hash = fib_info_hashfn_1(cfg->fc_nh_id, cfg->fc_protocol, cfg->fc_scope, (__force u32)cfg->fc_prefsrc, cfg->fc_priority); hash = fib_info_hashfn_result(net, hash); head = &fib_info_hash[hash]; hlist_for_each_entry(fi, head, fib_hash) { if (!net_eq(fi->fib_net, net)) continue; if (!fi->nh || fi->nh->id != cfg->fc_nh_id) continue; if (cfg->fc_protocol == fi->fib_protocol && cfg->fc_scope == fi->fib_scope && cfg->fc_prefsrc == fi->fib_prefsrc && cfg->fc_priority == fi->fib_priority && cfg->fc_type == fi->fib_type && cfg->fc_table == fi->fib_tb_id && !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK)) return fi; } return NULL; } static struct fib_info *fib_find_info(struct fib_info *nfi) { struct hlist_head *head; struct fib_info *fi; unsigned int hash; hash = fib_info_hashfn(nfi); head = &fib_info_hash[hash]; hlist_for_each_entry(fi, 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_scope == fi->fib_scope && nfi->fib_prefsrc == fi->fib_prefsrc && nfi->fib_priority == fi->fib_priority && nfi->fib_type == fi->fib_type && nfi->fib_tb_id == fi->fib_tb_id && memcmp(nfi->fib_metrics, fi->fib_metrics, sizeof(u32) * RTAX_MAX) == 0 && !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) && nh_comp(fi, nfi) == 0) return fi; } return NULL; } /* Check, that the gateway is already configured. * Used only by redirect accept routine, under rcu_read_lock(); */ int ip_fib_check_default(__be32 gw, struct net_device *dev) { struct hlist_head *head; struct fib_nh *nh; head = fib_nh_head(dev); hlist_for_each_entry_rcu(nh, head, nh_hash) { DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); if (nh->fib_nh_gw4 == gw && !(nh->fib_nh_flags & RTNH_F_DEAD)) { return 0; } } return -1; } 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 */ + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */ unsigned int nhs = fib_info_num_path(fi); /* space for nested metrics */ payload += nla_total_size((RTAX_MAX * nla_total_size(4))); if (fi->nh) payload += nla_total_size(4); /* RTA_NH_ID */ if (nhs) { size_t nh_encapsize = 0; /* Also handles the special case nhs == 1 */ /* each nexthop is packed in an attribute */ size_t nhsize = nla_total_size(sizeof(struct rtnexthop)); unsigned int i; /* may contain flow and gateway attribute */ nhsize += 2 * nla_total_size(4); /* grab encap info */ for (i = 0; i < fib_info_num_path(fi); i++) { struct fib_nh_common *nhc = fib_info_nhc(fi, i); if (nhc->nhc_lwtstate) { /* RTA_ENCAP_TYPE */ nh_encapsize += lwtunnel_get_encap_size( nhc->nhc_lwtstate); /* RTA_ENCAP */ nh_encapsize += nla_total_size(2); } } /* all nexthops are packed in a nested attribute */ payload += nla_total_size((nhs * nhsize) + nh_encapsize); } return payload; } void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, int dst_len, u32 tb_id, const struct nl_info *info, unsigned int nlm_flags) { struct fib_rt_info fri; 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) goto errout; fri.fi = fa->fa_info; fri.tb_id = tb_id; fri.dst = key; fri.dst_len = dst_len; fri.dscp = fa->fa_dscp; fri.type = fa->fa_type; fri.offload = READ_ONCE(fa->offload); fri.trap = READ_ONCE(fa->trap); fri.offload_failed = READ_ONCE(fa->offload_failed); err = fib_dump_info(skb, info->portid, seq, event, &fri, 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->portid, RTNLGRP_IPV4_ROUTE, info->nlh, GFP_KERNEL); return; errout: rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err); } static int fib_detect_death(struct fib_info *fi, int order, struct fib_info **last_resort, int *last_idx, int dflt) { const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); struct neighbour *n; int state = NUD_NONE; if (likely(nhc->nhc_gw_family == AF_INET)) n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev); else if (nhc->nhc_gw_family == AF_INET6) n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6, nhc->nhc_dev); else n = NULL; if (n) { state = READ_ONCE(n->nud_state); neigh_release(n); } else { return 0; } if (state == NUD_REACHABLE) return 0; if ((state & NUD_VALID) && order != dflt) return 0; if ((state & NUD_VALID) || (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) { *last_resort = fi; *last_idx = order; } return 1; } int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc, struct nlattr *encap, u16 encap_type, void *cfg, gfp_t gfp_flags, struct netlink_ext_ack *extack) { int err; nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, gfp_flags); if (!nhc->nhc_pcpu_rth_output) return -ENOMEM; if (encap) { struct lwtunnel_state *lwtstate; if (encap_type == LWTUNNEL_ENCAP_NONE) { NL_SET_ERR_MSG(extack, "LWT encap type not specified"); err = -EINVAL; goto lwt_failure; } err = lwtunnel_build_state(net, encap_type, encap, nhc->nhc_family, cfg, &lwtstate, extack); if (err) goto lwt_failure; nhc->nhc_lwtstate = lwtstate_get(lwtstate); } return 0; lwt_failure: rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output); nhc->nhc_pcpu_rth_output = NULL; return err; } EXPORT_SYMBOL_GPL(fib_nh_common_init); int fib_nh_init(struct net *net, struct fib_nh *nh, struct fib_config *cfg, int nh_weight, struct netlink_ext_ack *extack) { int err; nh->fib_nh_family = AF_INET; err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap, cfg->fc_encap_type, cfg, GFP_KERNEL, extack); if (err) return err; nh->fib_nh_oif = cfg->fc_oif; nh->fib_nh_gw_family = cfg->fc_gw_family; if (cfg->fc_gw_family == AF_INET) nh->fib_nh_gw4 = cfg->fc_gw4; else if (cfg->fc_gw_family == AF_INET6) nh->fib_nh_gw6 = cfg->fc_gw6; nh->fib_nh_flags = cfg->fc_flags; #ifdef CONFIG_IP_ROUTE_CLASSID nh->nh_tclassid = cfg->fc_flow; if (nh->nh_tclassid) atomic_inc(&net->ipv4.fib_num_tclassid_users); #endif #ifdef CONFIG_IP_ROUTE_MULTIPATH nh->fib_nh_weight = nh_weight; #endif return 0; } #ifdef CONFIG_IP_ROUTE_MULTIPATH static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, struct netlink_ext_ack *extack) { int nhs = 0; while (rtnh_ok(rtnh, remaining)) { nhs++; rtnh = rtnh_next(rtnh, &remaining); } /* leftover implies invalid nexthop configuration, discard it */ if (remaining > 0) { NL_SET_ERR_MSG(extack, "Invalid nexthop configuration - extra data after nexthops"); nhs = 0; } return nhs; } static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla, struct netlink_ext_ack *extack) { if (nla_len(nla) < sizeof(*gw)) { NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY"); return -EINVAL; } *gw = nla_get_in_addr(nla); return 0; } /* only called when fib_nh is integrated into fib_info */ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, int remaining, struct fib_config *cfg, struct netlink_ext_ack *extack) { struct net *net = fi->fib_net; struct fib_config fib_cfg; struct fib_nh *nh; int ret; change_nexthops(fi) { int attrlen; memset(&fib_cfg, 0, sizeof(fib_cfg)); if (!rtnh_ok(rtnh, remaining)) { NL_SET_ERR_MSG(extack, "Invalid nexthop configuration - extra data after nexthop"); return -EINVAL; } if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { NL_SET_ERR_MSG(extack, "Invalid flags for nexthop - can not contain DEAD or LINKDOWN"); return -EINVAL; } fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags; fib_cfg.fc_oif = rtnh->rtnh_ifindex; attrlen = rtnh_attrlen(rtnh); if (attrlen > 0) { struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); nla = nla_find(attrs, attrlen, RTA_GATEWAY); nlav = nla_find(attrs, attrlen, RTA_VIA); if (nla && nlav) { NL_SET_ERR_MSG(extack, "Nexthop configuration can not contain both GATEWAY and VIA"); return -EINVAL; } if (nla) { ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla, extack); if (ret) goto errout; if (fib_cfg.fc_gw4) fib_cfg.fc_gw_family = AF_INET; } else if (nlav) { ret = fib_gw_from_via(&fib_cfg, nlav, extack); if (ret) goto errout; } nla = nla_find(attrs, attrlen, RTA_FLOW); if (nla) { if (nla_len(nla) < sizeof(u32)) { NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); return -EINVAL; } fib_cfg.fc_flow = nla_get_u32(nla); } fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP); /* RTA_ENCAP_TYPE length checked in * lwtunnel_valid_encap_type_attr */ nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE); if (nla) fib_cfg.fc_encap_type = nla_get_u16(nla); } ret = fib_nh_init(net, nexthop_nh, &fib_cfg, rtnh->rtnh_hops + 1, extack); if (ret) goto errout; rtnh = rtnh_next(rtnh, &remaining); } endfor_nexthops(fi); ret = -EINVAL; nh = fib_info_nh(fi, 0); if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) { NL_SET_ERR_MSG(extack, "Nexthop device index does not match RTA_OIF"); goto errout; } if (cfg->fc_gw_family) { if (cfg->fc_gw_family != nh->fib_nh_gw_family || (cfg->fc_gw_family == AF_INET && nh->fib_nh_gw4 != cfg->fc_gw4) || (cfg->fc_gw_family == AF_INET6 && ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) { NL_SET_ERR_MSG(extack, "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA"); goto errout; } } #ifdef CONFIG_IP_ROUTE_CLASSID if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) { NL_SET_ERR_MSG(extack, "Nexthop class id does not match RTA_FLOW"); goto errout; } #endif ret = 0; errout: return ret; } /* only called when fib_nh is integrated into fib_info */ static void fib_rebalance(struct fib_info *fi) { int total; int w; if (fib_info_num_path(fi) < 2) return; total = 0; for_nexthops(fi) { if (nh->fib_nh_flags & RTNH_F_DEAD) continue; if (ip_ignore_linkdown(nh->fib_nh_dev) && nh->fib_nh_flags & RTNH_F_LINKDOWN) continue; total += nh->fib_nh_weight; } endfor_nexthops(fi); w = 0; change_nexthops(fi) { int upper_bound; if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) { upper_bound = -1; } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) && nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) { upper_bound = -1; } else { w += nexthop_nh->fib_nh_weight; upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1; } atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound); } endfor_nexthops(fi); } #else /* CONFIG_IP_ROUTE_MULTIPATH */ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh, int remaining, struct fib_config *cfg, struct netlink_ext_ack *extack) { NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel"); return -EINVAL; } #define fib_rebalance(fi) do { } while (0) #endif /* CONFIG_IP_ROUTE_MULTIPATH */ static int fib_encap_match(struct net *net, u16 encap_type, struct nlattr *encap, const struct fib_nh *nh, const struct fib_config *cfg, struct netlink_ext_ack *extack) { struct lwtunnel_state *lwtstate; int ret, result = 0; if (encap_type == LWTUNNEL_ENCAP_NONE) return 0; ret = lwtunnel_build_state(net, encap_type, encap, AF_INET, cfg, &lwtstate, extack); if (!ret) { result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws); lwtstate_free(lwtstate); } return result; } int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi, struct netlink_ext_ack *extack) { #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_nh_id) { if (fi->nh && cfg->fc_nh_id == fi->nh->id) return 0; return 1; } if (fi->nh) { if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp) return 1; return 0; } if (cfg->fc_oif || cfg->fc_gw_family) { struct fib_nh *nh; nh = fib_info_nh(fi, 0); if (cfg->fc_encap) { if (fib_encap_match(net, cfg->fc_encap_type, cfg->fc_encap, nh, cfg, extack)) return 1; } #ifdef CONFIG_IP_ROUTE_CLASSID if (cfg->fc_flow && cfg->fc_flow != nh->nh_tclassid) return 1; #endif if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) || (cfg->fc_gw_family && cfg->fc_gw_family != nh->fib_nh_gw_family)) return 1; if (cfg->fc_gw_family == AF_INET && cfg->fc_gw4 != nh->fib_nh_gw4) return 1; if (cfg->fc_gw_family == AF_INET6 && ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6)) return 1; return 0; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (!cfg->fc_mp) 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->fib_nh_oif) return 1; attrlen = rtnh_attrlen(rtnh); if (attrlen > 0) { struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh); int err; nla = nla_find(attrs, attrlen, RTA_GATEWAY); nlav = nla_find(attrs, attrlen, RTA_VIA); if (nla && nlav) { NL_SET_ERR_MSG(extack, "Nexthop configuration can not contain both GATEWAY and VIA"); return -EINVAL; } if (nla) { __be32 gw; err = fib_gw_from_attr(&gw, nla, extack); if (err) return err; if (nh->fib_nh_gw_family != AF_INET || gw != nh->fib_nh_gw4) return 1; } else if (nlav) { struct fib_config cfg2; err = fib_gw_from_via(&cfg2, nlav, extack); if (err) return err; switch (nh->fib_nh_gw_family) { case AF_INET: if (cfg2.fc_gw_family != AF_INET || cfg2.fc_gw4 != nh->fib_nh_gw4) return 1; break; case AF_INET6: if (cfg2.fc_gw_family != AF_INET6 || ipv6_addr_cmp(&cfg2.fc_gw6, &nh->fib_nh_gw6)) return 1; break; } } #ifdef CONFIG_IP_ROUTE_CLASSID nla = nla_find(attrs, attrlen, RTA_FLOW); if (nla) { if (nla_len(nla) < sizeof(u32)) { NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW"); return -EINVAL; } if (nla_get_u32(nla) != nh->nh_tclassid) return 1; } #endif } rtnh = rtnh_next(rtnh, &remaining); } endfor_nexthops(fi); #endif return 0; } bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi) { struct nlattr *nla; int remaining; if (!cfg->fc_mx) return true; nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { int type = nla_type(nla); u32 fi_val, val; if (!type) continue; if (type > RTAX_MAX) return false; type = array_index_nospec(type, RTAX_MAX + 1); if (type == RTAX_CC_ALGO) { char tmp[TCP_CA_NAME_MAX]; bool ecn_ca = false; nla_strscpy(tmp, nla, sizeof(tmp)); val = tcp_ca_get_key_by_name(tmp, &ecn_ca); } else { if (nla_len(nla) != sizeof(u32)) return false; val = nla_get_u32(nla); } fi_val = fi->fib_metrics->metrics[type - 1]; if (type == RTAX_FEATURES) fi_val &= ~DST_FEATURE_ECN_CA; if (fi_val != val) return false; } return true; } static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh, u32 table, struct netlink_ext_ack *extack) { struct fib6_config cfg = { .fc_table = table, .fc_flags = nh->fib_nh_flags | RTF_GATEWAY, .fc_ifindex = nh->fib_nh_oif, .fc_gateway = nh->fib_nh_gw6, }; struct fib6_nh fib6_nh = {}; int err; err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack); if (!err) { nh->fib_nh_dev = fib6_nh.fib_nh_dev; netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL); nh->fib_nh_oif = nh->fib_nh_dev->ifindex; nh->fib_nh_scope = RT_SCOPE_LINK; ipv6_stub->fib6_nh_release(&fib6_nh); } return err; } /* * 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_v4_gw(struct net *net, struct fib_nh *nh, u32 table, u8 scope, struct netlink_ext_ack *extack) { struct net_device *dev; struct fib_result res; int err = 0; if (nh->fib_nh_flags & RTNH_F_ONLINK) { unsigned int addr_type; if (scope >= RT_SCOPE_LINK) { NL_SET_ERR_MSG(extack, "Nexthop has invalid scope"); return -EINVAL; } dev = __dev_get_by_index(net, nh->fib_nh_oif); if (!dev) { NL_SET_ERR_MSG(extack, "Nexthop device required for onlink"); return -ENODEV; } if (!(dev->flags & IFF_UP)) { NL_SET_ERR_MSG(extack, "Nexthop device is not up"); return -ENETDOWN; } addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4); if (addr_type != RTN_UNICAST) { NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); return -EINVAL; } if (!netif_carrier_ok(dev)) nh->fib_nh_flags |= RTNH_F_LINKDOWN; nh->fib_nh_dev = dev; netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); nh->fib_nh_scope = RT_SCOPE_LINK; return 0; } rcu_read_lock(); { struct fib_table *tbl = NULL; struct flowi4 fl4 = { .daddr = nh->fib_nh_gw4, .flowi4_scope = scope + 1, .flowi4_oif = nh->fib_nh_oif, .flowi4_iif = LOOPBACK_IFINDEX, }; /* It is not necessary, but requires a bit of thinking */ if (fl4.flowi4_scope < RT_SCOPE_LINK) fl4.flowi4_scope = RT_SCOPE_LINK; if (table && table != RT_TABLE_MAIN) tbl = fib_get_table(net, table); if (tbl) err = fib_table_lookup(tbl, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE | FIB_LOOKUP_NOREF); /* on error or if no table given do full lookup. This * is needed for example when nexthops are in the local * table rather than the given table */ if (!tbl || err) { err = fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE); } if (err) { NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); goto out; } } err = -EINVAL; if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) { NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway"); goto out; } nh->fib_nh_scope = res.scope; nh->fib_nh_oif = FIB_RES_OIF(res); nh->fib_nh_dev = dev = FIB_RES_DEV(res); if (!dev) { NL_SET_ERR_MSG(extack, "No egress device for nexthop gateway"); goto out; } netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); if (!netif_carrier_ok(dev)) nh->fib_nh_flags |= RTNH_F_LINKDOWN; err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN; out: rcu_read_unlock(); return err; } static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh, struct netlink_ext_ack *extack) { struct in_device *in_dev; int err; if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) { NL_SET_ERR_MSG(extack, "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set"); return -EINVAL; } rcu_read_lock(); err = -ENODEV; in_dev = inetdev_by_index(net, nh->fib_nh_oif); if (!in_dev) goto out; err = -ENETDOWN; if (!(in_dev->dev->flags & IFF_UP)) { NL_SET_ERR_MSG(extack, "Device for nexthop is not up"); goto out; } nh->fib_nh_dev = in_dev->dev; netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC); nh->fib_nh_scope = RT_SCOPE_HOST; if (!netif_carrier_ok(nh->fib_nh_dev)) nh->fib_nh_flags |= RTNH_F_LINKDOWN; err = 0; out: rcu_read_unlock(); return err; } int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope, struct netlink_ext_ack *extack) { int err; if (nh->fib_nh_gw_family == AF_INET) err = fib_check_nh_v4_gw(net, nh, table, scope, extack); else if (nh->fib_nh_gw_family == AF_INET6) err = fib_check_nh_v6_gw(net, nh, table, extack); else err = fib_check_nh_nongw(net, nh, extack); return err; } static struct hlist_head * fib_info_laddrhash_bucket(const struct net *net, __be32 val) { u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, fib_info_hash_bits); return &fib_info_laddrhash[slot]; } static void fib_info_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_info_hash_size; unsigned int i; ASSERT_RTNL(); old_info_hash = fib_info_hash; old_laddrhash = fib_info_laddrhash; fib_info_hash_size = new_size; fib_info_hash_bits = ilog2(new_size); for (i = 0; i < old_size; i++) { struct hlist_head *head = &fib_info_hash[i]; struct hlist_node *n; struct fib_info *fi; hlist_for_each_entry_safe(fi, n, head, fib_hash) { struct hlist_head *dest; unsigned int new_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; fib_info_laddrhash = new_laddrhash; for (i = 0; i < old_size; i++) { struct hlist_head *lhead = &old_laddrhash[i]; struct hlist_node *n; struct fib_info *fi; hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) { struct hlist_head *ldest; ldest = fib_info_laddrhash_bucket(fi->fib_net, fi->fib_prefsrc); hlist_add_head(&fi->fib_lhash, ldest); } } kvfree(old_info_hash); kvfree(old_laddrhash); } __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc, unsigned char scope) { struct fib_nh *nh; __be32 saddr; if (nhc->nhc_family != AF_INET) return inet_select_addr(nhc->nhc_dev, 0, scope); nh = container_of(nhc, struct fib_nh, nh_common); saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope); WRITE_ONCE(nh->nh_saddr, saddr); WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid)); return saddr; } __be32 fib_result_prefsrc(struct net *net, struct fib_result *res) { struct fib_nh_common *nhc = res->nhc; if (res->fi->fib_prefsrc) return res->fi->fib_prefsrc; if (nhc->nhc_family == AF_INET) { struct fib_nh *nh; nh = container_of(nhc, struct fib_nh, nh_common); if (READ_ONCE(nh->nh_saddr_genid) == atomic_read(&net->ipv4.dev_addr_genid)) return READ_ONCE(nh->nh_saddr); } return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope); } static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc) { if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst || fib_prefsrc != cfg->fc_dst) { u32 tb_id = cfg->fc_table; int rc; if (tb_id == RT_TABLE_MAIN) tb_id = RT_TABLE_LOCAL; rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, fib_prefsrc, tb_id); if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) { rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net, fib_prefsrc, RT_TABLE_LOCAL); } if (rc != RTN_LOCAL) return false; } return true; } struct fib_info *fib_create_info(struct fib_config *cfg, struct netlink_ext_ack *extack) { int err; struct fib_info *fi = NULL; struct nexthop *nh = NULL; struct fib_info *ofi; int nhs = 1; struct net *net = cfg->fc_nlinfo.nl_net; ASSERT_RTNL(); if (cfg->fc_type > RTN_MAX) goto err_inval; /* Fast check to catch the most weird cases */ if (fib_props[cfg->fc_type].scope > cfg->fc_scope) { NL_SET_ERR_MSG(extack, "Invalid scope"); goto err_inval; } if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) { NL_SET_ERR_MSG(extack, "Invalid rtm_flags - can not contain DEAD or LINKDOWN"); goto err_inval; } if (cfg->fc_nh_id) { if (!cfg->fc_mx) { fi = fib_find_info_nh(net, cfg); if (fi) { refcount_inc(&fi->fib_treeref); return fi; } } nh = nexthop_find_by_id(net, cfg->fc_nh_id); if (!nh) { NL_SET_ERR_MSG(extack, "Nexthop id does not exist"); goto err_inval; } nhs = 0; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (cfg->fc_mp) { nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack); if (nhs == 0) goto err_inval; } #endif err = -ENOBUFS; if (fib_info_cnt >= fib_info_hash_size) { unsigned int new_size = fib_info_hash_size << 1; struct hlist_head *new_info_hash; struct hlist_head *new_laddrhash; size_t bytes; if (!new_size) new_size = 16; bytes = (size_t)new_size * sizeof(struct hlist_head *); new_info_hash = kvzalloc(bytes, GFP_KERNEL); new_laddrhash = kvzalloc(bytes, GFP_KERNEL); if (!new_info_hash || !new_laddrhash) { kvfree(new_info_hash); kvfree(new_laddrhash); } else { fib_info_hash_move(new_info_hash, new_laddrhash, new_size); } if (!fib_info_hash_size) goto failure; } fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL); if (!fi) goto failure; fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack); if (IS_ERR(fi->fib_metrics)) { err = PTR_ERR(fi->fib_metrics); kfree(fi); return ERR_PTR(err); } fi->fib_net = net; fi->fib_protocol = cfg->fc_protocol; fi->fib_scope = cfg->fc_scope; fi->fib_flags = cfg->fc_flags; fi->fib_priority = cfg->fc_priority; fi->fib_prefsrc = cfg->fc_prefsrc; fi->fib_type = cfg->fc_type; fi->fib_tb_id = cfg->fc_table; fi->fib_nhs = nhs; if (nh) { if (!nexthop_get(nh)) { NL_SET_ERR_MSG(extack, "Nexthop has been deleted"); err = -EINVAL; } else { err = 0; fi->nh = nh; } } else { change_nexthops(fi) { nexthop_nh->nh_parent = fi; } endfor_nexthops(fi) if (cfg->fc_mp) err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack); else err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack); } if (err != 0) goto failure; if (fib_props[cfg->fc_type].error) { if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) { NL_SET_ERR_MSG(extack, "Gateway, device and multipath can not be specified for this route type"); goto err_inval; } goto link_it; } else { switch (cfg->fc_type) { case RTN_UNICAST: case RTN_LOCAL: case RTN_BROADCAST: case RTN_ANYCAST: case RTN_MULTICAST: break; default: NL_SET_ERR_MSG(extack, "Invalid route type"); goto err_inval; } } if (cfg->fc_scope > RT_SCOPE_HOST) { NL_SET_ERR_MSG(extack, "Invalid scope"); goto err_inval; } if (fi->nh) { err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack); if (err) goto failure; } else if (cfg->fc_scope == RT_SCOPE_HOST) { struct fib_nh *nh = fi->fib_nh; /* Local address is added. */ if (nhs != 1) { NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops"); goto err_inval; } if (nh->fib_nh_gw_family) { NL_SET_ERR_MSG(extack, "Route with host scope can not have a gateway"); goto err_inval; } nh->fib_nh_scope = RT_SCOPE_NOWHERE; nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif); err = -ENODEV; if (!nh->fib_nh_dev) goto failure; netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL); } else { int linkdown = 0; change_nexthops(fi) { err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh, cfg->fc_table, cfg->fc_scope, extack); if (err != 0) goto failure; if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) linkdown++; } endfor_nexthops(fi) if (linkdown == fi->fib_nhs) fi->fib_flags |= RTNH_F_LINKDOWN; } if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) { NL_SET_ERR_MSG(extack, "Invalid prefsrc address"); goto err_inval; } if (!fi->nh) { change_nexthops(fi) { fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common, fi->fib_scope); if (nexthop_nh->fib_nh_gw_family == AF_INET6) fi->fib_nh_is_v6 = true; } endfor_nexthops(fi) fib_rebalance(fi); } link_it: ofi = fib_find_info(fi); if (ofi) { /* fib_table_lookup() should not see @fi yet. */ fi->fib_dead = 1; free_fib_info(fi); refcount_inc(&ofi->fib_treeref); return ofi; } refcount_set(&fi->fib_treeref, 1); refcount_set(&fi->fib_clntref, 1); fib_info_cnt++; 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_bucket(net, fi->fib_prefsrc); hlist_add_head(&fi->fib_lhash, head); } if (fi->nh) { list_add(&fi->nh_list, &nh->fi_list); } else { change_nexthops(fi) { struct hlist_head *head; if (!nexthop_nh->fib_nh_dev) continue; head = fib_nh_head(nexthop_nh->fib_nh_dev); hlist_add_head_rcu(&nexthop_nh->nh_hash, head); } endfor_nexthops(fi) } return fi; err_inval: err = -EINVAL; failure: if (fi) { /* fib_table_lookup() should not see @fi yet. */ fi->fib_dead = 1; free_fib_info(fi); } return ERR_PTR(err); } int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc, u8 rt_family, unsigned char *flags, bool skip_oif) { if (nhc->nhc_flags & RTNH_F_DEAD) *flags |= RTNH_F_DEAD; if (nhc->nhc_flags & RTNH_F_LINKDOWN) { *flags |= RTNH_F_LINKDOWN; rcu_read_lock(); switch (nhc->nhc_family) { case AF_INET: if (ip_ignore_linkdown(nhc->nhc_dev)) *flags |= RTNH_F_DEAD; break; case AF_INET6: if (ip6_ignore_linkdown(nhc->nhc_dev)) *flags |= RTNH_F_DEAD; break; } rcu_read_unlock(); } switch (nhc->nhc_gw_family) { case AF_INET: if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4)) goto nla_put_failure; break; case AF_INET6: /* if gateway family does not match nexthop family * gateway is encoded as RTA_VIA */ if (rt_family != nhc->nhc_gw_family) { int alen = sizeof(struct in6_addr); struct nlattr *nla; struct rtvia *via; nla = nla_reserve(skb, RTA_VIA, alen + 2); if (!nla) goto nla_put_failure; via = nla_data(nla); via->rtvia_family = AF_INET6; memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen); } else if (nla_put_in6_addr(skb, RTA_GATEWAY, &nhc->nhc_gw.ipv6) < 0) { goto nla_put_failure; } break; } *flags |= (nhc->nhc_flags & (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP)); if (!skip_oif && nhc->nhc_dev && nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex)) goto nla_put_failure; if (nhc->nhc_lwtstate && lwtunnel_fill_encap(skb, nhc->nhc_lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) goto nla_put_failure; return 0; nla_put_failure: return -EMSGSIZE; } EXPORT_SYMBOL_GPL(fib_nexthop_info); #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6) int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc, int nh_weight, u8 rt_family, u32 nh_tclassid) { const struct net_device *dev = nhc->nhc_dev; struct rtnexthop *rtnh; unsigned char flags = 0; rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); if (!rtnh) goto nla_put_failure; rtnh->rtnh_hops = nh_weight - 1; rtnh->rtnh_ifindex = dev ? dev->ifindex : 0; if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0) goto nla_put_failure; rtnh->rtnh_flags = flags; if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid)) goto nla_put_failure; /* length of rtnetlink header + attributes */ rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; return 0; nla_put_failure: return -EMSGSIZE; } EXPORT_SYMBOL_GPL(fib_add_nexthop); #endif #ifdef CONFIG_IP_ROUTE_MULTIPATH static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) { struct nlattr *mp; mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); if (!mp) goto nla_put_failure; if (unlikely(fi->nh)) { if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0) goto nla_put_failure; goto mp_end; } for_nexthops(fi) { u32 nh_tclassid = 0; #ifdef CONFIG_IP_ROUTE_CLASSID nh_tclassid = nh->nh_tclassid; #endif if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight, AF_INET, nh_tclassid) < 0) goto nla_put_failure; } endfor_nexthops(fi); mp_end: nla_nest_end(skb, mp); return 0; nla_put_failure: return -EMSGSIZE; } #else static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) { return 0; } #endif int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, const struct fib_rt_info *fri, unsigned int flags) { unsigned int nhs = fib_info_num_path(fri->fi); struct fib_info *fi = fri->fi; u32 tb_id = fri->tb_id; struct nlmsghdr *nlh; struct rtmsg *rtm; nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags); if (!nlh) return -EMSGSIZE; rtm = nlmsg_data(nlh); rtm->rtm_family = AF_INET; rtm->rtm_dst_len = fri->dst_len; rtm->rtm_src_len = 0; rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp); if (tb_id < 256) rtm->rtm_table = tb_id; else rtm->rtm_table = RT_TABLE_COMPAT; if (nla_put_u32(skb, RTA_TABLE, tb_id)) goto nla_put_failure; rtm->rtm_type = fri->type; rtm->rtm_flags = fi->fib_flags; rtm->rtm_scope = fi->fib_scope; rtm->rtm_protocol = fi->fib_protocol; if (rtm->rtm_dst_len && nla_put_in_addr(skb, RTA_DST, fri->dst)) goto nla_put_failure; if (fi->fib_priority && nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority)) goto nla_put_failure; if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0) goto nla_put_failure; if (fi->fib_prefsrc && nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) goto nla_put_failure; if (fi->nh) { if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id)) goto nla_put_failure; if (nexthop_is_blackhole(fi->nh)) rtm->rtm_type = RTN_BLACKHOLE; if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode)) goto offload; } if (nhs == 1) { const struct fib_nh_common *nhc = fib_info_nhc(fi, 0); unsigned char flags = 0; if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0) goto nla_put_failure; rtm->rtm_flags = flags; #ifdef CONFIG_IP_ROUTE_CLASSID if (nhc->nhc_family == AF_INET) { struct fib_nh *nh; nh = container_of(nhc, struct fib_nh, nh_common); if (nh->nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid)) goto nla_put_failure; } #endif } else { if (fib_add_multipath(skb, fi) < 0) goto nla_put_failure; } offload: if (fri->offload) rtm->rtm_flags |= RTM_F_OFFLOAD; if (fri->trap) rtm->rtm_flags |= RTM_F_TRAP; if (fri->offload_failed) rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; nlmsg_end(skb, nlh); return 0; 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_device *dev, __be32 local) { int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN; struct net *net = dev_net(dev); struct hlist_head *head; struct fib_info *fi; int ret = 0; if (!fib_info_laddrhash || local == 0) return 0; head = fib_info_laddrhash_bucket(net, local); hlist_for_each_entry(fi, head, fib_lhash) { if (!net_eq(fi->fib_net, net) || fi->fib_tb_id != tb_id) continue; if (fi->fib_prefsrc == local) { fi->fib_flags |= RTNH_F_DEAD; fi->pfsrc_removed = true; ret++; } } return ret; } static int call_fib_nh_notifiers(struct fib_nh *nh, enum fib_event_type event_type) { bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev); struct fib_nh_notifier_info info = { .fib_nh = nh, }; switch (event_type) { case FIB_EVENT_NH_ADD: if (nh->fib_nh_flags & RTNH_F_DEAD) break; if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) break; return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, &info.info); case FIB_EVENT_NH_DEL: if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) || (nh->fib_nh_flags & RTNH_F_DEAD)) return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type, &info.info); break; default: break; } return NOTIFY_DONE; } /* Update the PMTU of exceptions when: * - the new MTU of the first hop becomes smaller than the PMTU * - the old MTU was the same as the PMTU, and it limited discovery of * larger MTUs on the path. With that limit raised, we can now * discover larger MTUs * A special case is locked exceptions, for which the PMTU is smaller * than the minimal accepted PMTU: * - if the new MTU is greater than the PMTU, don't make any change * - otherwise, unlock and set PMTU */ void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig) { struct fnhe_hash_bucket *bucket; int i; bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1); if (!bucket) return; for (i = 0; i < FNHE_HASH_SIZE; i++) { struct fib_nh_exception *fnhe; for (fnhe = rcu_dereference_protected(bucket[i].chain, 1); fnhe; fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) { if (fnhe->fnhe_mtu_locked) { if (new <= fnhe->fnhe_pmtu) { fnhe->fnhe_pmtu = new; fnhe->fnhe_mtu_locked = false; } } else if (new < fnhe->fnhe_pmtu || orig == fnhe->fnhe_pmtu) { fnhe->fnhe_pmtu = new; } } } } void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) { struct hlist_head *head = fib_nh_head(dev); struct fib_nh *nh; hlist_for_each_entry(nh, head, nh_hash) { DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu); } } /* Event force Flags Description * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed * * only used when fib_nh is built into fib_info */ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) { struct hlist_head *head = fib_nh_head(dev); struct fib_info *prev_fi = NULL; int scope = RT_SCOPE_NOWHERE; struct fib_nh *nh; int ret = 0; if (force) scope = -1; hlist_for_each_entry(nh, head, nh_hash) { struct fib_info *fi = nh->nh_parent; int dead; BUG_ON(!fi->fib_nhs); DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); if (fi == prev_fi) continue; prev_fi = fi; dead = 0; change_nexthops(fi) { if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) dead++; else if (nexthop_nh->fib_nh_dev == dev && nexthop_nh->fib_nh_scope != scope) { switch (event) { case NETDEV_DOWN: case NETDEV_UNREGISTER: nexthop_nh->fib_nh_flags |= RTNH_F_DEAD; fallthrough; case NETDEV_CHANGE: nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN; break; } call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_DEL); dead++; } #ifdef CONFIG_IP_ROUTE_MULTIPATH if (event == NETDEV_UNREGISTER && nexthop_nh->fib_nh_dev == dev) { dead = fi->fib_nhs; break; } #endif } endfor_nexthops(fi) if (dead == fi->fib_nhs) { switch (event) { case NETDEV_DOWN: case NETDEV_UNREGISTER: fi->fib_flags |= RTNH_F_DEAD; fallthrough; case NETDEV_CHANGE: fi->fib_flags |= RTNH_F_LINKDOWN; break; } ret++; } fib_rebalance(fi); } return ret; } /* Must be invoked inside of an RCU protected region. */ static void fib_select_default(const struct flowi4 *flp, struct fib_result *res) { struct fib_info *fi = NULL, *last_resort = NULL; struct hlist_head *fa_head = res->fa_head; struct fib_table *tb = res->table; u8 slen = 32 - res->prefixlen; int order = -1, last_idx = -1; struct fib_alias *fa, *fa1 = NULL; u32 last_prio = res->fi->fib_priority; dscp_t last_dscp = 0; hlist_for_each_entry_rcu(fa, fa_head, fa_list) { struct fib_info *next_fi = fa->fa_info; struct fib_nh_common *nhc; if (fa->fa_slen != slen) continue; if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp)) continue; if (fa->tb_id != tb->tb_id) continue; if (next_fi->fib_priority > last_prio && fa->fa_dscp == last_dscp) { if (last_dscp) continue; break; } if (next_fi->fib_flags & RTNH_F_DEAD) continue; last_dscp = fa->fa_dscp; last_prio = next_fi->fib_priority; if (next_fi->fib_scope != res->scope || fa->fa_type != RTN_UNICAST) continue; nhc = fib_info_nhc(next_fi, 0); if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK) continue; fib_alias_accessed(fa); if (!fi) { if (next_fi != res->fi) break; fa1 = fa; } else if (!fib_detect_death(fi, order, &last_resort, &last_idx, fa1->fa_default)) { fib_result_assign(res, fi); fa1->fa_default = order; goto out; } fi = next_fi; order++; } if (order <= 0 || !fi) { if (fa1) fa1->fa_default = -1; goto out; } if (!fib_detect_death(fi, order, &last_resort, &last_idx, fa1->fa_default)) { fib_result_assign(res, fi); fa1->fa_default = order; goto out; } if (last_idx >= 0) fib_result_assign(res, last_resort); fa1->fa_default = last_idx; out: return; } /* * Dead device goes up. We wake up dead nexthops. * It takes sense only on multipath routes. * * only used when fib_nh is built into fib_info */ int fib_sync_up(struct net_device *dev, unsigned char nh_flags) { struct fib_info *prev_fi; struct hlist_head *head; struct fib_nh *nh; int ret; if (!(dev->flags & IFF_UP)) return 0; if (nh_flags & RTNH_F_DEAD) { unsigned int flags = dev_get_flags(dev); if (flags & (IFF_RUNNING | IFF_LOWER_UP)) nh_flags |= RTNH_F_LINKDOWN; } prev_fi = NULL; head = fib_nh_head(dev); ret = 0; hlist_for_each_entry(nh, head, nh_hash) { struct fib_info *fi = nh->nh_parent; int alive; BUG_ON(!fi->fib_nhs); DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev); if (fi == prev_fi) continue; prev_fi = fi; alive = 0; change_nexthops(fi) { if (!(nexthop_nh->fib_nh_flags & nh_flags)) { alive++; continue; } if (!nexthop_nh->fib_nh_dev || !(nexthop_nh->fib_nh_dev->flags & IFF_UP)) continue; if (nexthop_nh->fib_nh_dev != dev || !__in_dev_get_rtnl(dev)) continue; alive++; nexthop_nh->fib_nh_flags &= ~nh_flags; call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); } endfor_nexthops(fi) if (alive > 0) { fi->fib_flags &= ~nh_flags; ret++; } fib_rebalance(fi); } return ret; } #ifdef CONFIG_IP_ROUTE_MULTIPATH static bool fib_good_nh(const struct fib_nh *nh) { int state = NUD_REACHABLE; if (nh->fib_nh_scope == RT_SCOPE_LINK) { struct neighbour *n; rcu_read_lock(); if (likely(nh->fib_nh_gw_family == AF_INET)) n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, (__force u32)nh->fib_nh_gw4); else if (nh->fib_nh_gw_family == AF_INET6) n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6); else n = NULL; if (n) state = READ_ONCE(n->nud_state); rcu_read_unlock(); } return !!(state & NUD_VALID); } void fib_select_multipath(struct fib_result *res, int hash) { struct fib_info *fi = res->fi; struct net *net = fi->fib_net; bool first = false; if (unlikely(res->fi->nh)) { nexthop_path_fib_result(res, hash); return; } change_nexthops(fi) { if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { if (!fib_good_nh(nexthop_nh)) continue; if (!first) { res->nh_sel = nhsel; res->nhc = &nexthop_nh->nh_common; first = true; } } if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound)) continue; res->nh_sel = nhsel; res->nhc = &nexthop_nh->nh_common; return; } endfor_nexthops(fi); } #endif void fib_select_path(struct net *net, struct fib_result *res, struct flowi4 *fl4, const struct sk_buff *skb) { if (fl4->flowi4_oif) goto check_saddr; #ifdef CONFIG_IP_ROUTE_MULTIPATH if (fib_info_num_path(res->fi) > 1) { int h = fib_multipath_hash(net, fl4, skb, NULL); fib_select_multipath(res, h); } else #endif if (!res->prefixlen && res->table->tb_num_default > 1 && res->type == RTN_UNICAST) fib_select_default(fl4, res); check_saddr: if (!fl4->saddr) { struct net_device *l3mdev; l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev); if (!l3mdev || l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev) fl4->saddr = fib_result_prefsrc(net, res); else fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK); } }