v4.19.13 snapshot.
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
new file mode 100644
index 0000000..446204c
--- /dev/null
+++ b/net/ipv4/fib_semantics.c
@@ -0,0 +1,1802 @@
+/*
+ * 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 <linux/uaccess.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 <linux/netlink.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 <net/lwtunnel.h>
+#include <net/fib_notifier.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_info_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
+
+#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) }
+
+
+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 *nh)
+{
+ struct fnhe_hash_bucket *hash;
+ int i;
+
+ hash = rcu_dereference_protected(nh->nh_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);
+}
+
+/* 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);
+ struct dst_metrics *m;
+
+ change_nexthops(fi) {
+ if (nexthop_nh->nh_dev)
+ dev_put(nexthop_nh->nh_dev);
+ lwtstate_put(nexthop_nh->nh_lwtstate);
+ free_nh_exceptions(nexthop_nh);
+ rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
+ rt_fibinfo_free(&nexthop_nh->nh_rth_input);
+ } endfor_nexthops(fi);
+
+ m = fi->fib_metrics;
+ if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
+ kfree(m);
+ 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;
+ }
+ fib_info_cnt--;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ change_nexthops(fi) {
+ if (nexthop_nh->nh_tclassid)
+ fi->fib_net->ipv4.fib_num_tclassid_users--;
+ } endfor_nexthops(fi);
+#endif
+ call_rcu(&fi->rcu, free_fib_info_rcu);
+}
+EXPORT_SYMBOL_GPL(free_fib_info);
+
+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_IP_ROUTE_CLASSID
+ nh->nh_tclassid != onh->nh_tclassid ||
+#endif
+ lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
+ ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
+ 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_info_hash_size - 1);
+ unsigned int val = fi->fib_nhs;
+
+ val ^= (fi->fib_protocol << 8) | fi->fib_scope;
+ 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 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 &&
+ memcmp(nfi->fib_metrics, fi->fib_metrics,
+ sizeof(u32) * RTAX_MAX) == 0 &&
+ !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
+ (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 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, 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 */
+ + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
+
+ /* space for nested metrics */
+ payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
+
+ if (fi->fib_nhs) {
+ size_t nh_encapsize = 0;
+ /* 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);
+
+ /* grab encap info */
+ for_nexthops(fi) {
+ if (nh->nh_lwtstate) {
+ /* RTA_ENCAP_TYPE */
+ nh_encapsize += lwtunnel_get_encap_size(
+ nh->nh_lwtstate);
+ /* RTA_ENCAP */
+ nh_encapsize += nla_total_size(2);
+ }
+ } endfor_nexthops(fi);
+
+ /* all nexthops are packed in a nested attribute */
+ payload += nla_total_size((fi->fib_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 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;
+
+ err = fib_dump_info(skb, info->portid, seq, event, tb_id,
+ fa->fa_type, 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->portid, RTNLGRP_IPV4_ROUTE,
+ info->nlh, GFP_KERNEL);
+ return;
+errout:
+ if (err < 0)
+ 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)
+{
+ 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);
+ } 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;
+}
+
+#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_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
+ int remaining, struct fib_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ int ret;
+
+ change_nexthops(fi) {
+ int attrlen;
+
+ 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;
+ }
+
+ 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_in_addr(nla) : 0;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ nla = nla_find(attrs, attrlen, RTA_FLOW);
+ nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
+ if (nexthop_nh->nh_tclassid)
+ fi->fib_net->ipv4.fib_num_tclassid_users++;
+#endif
+ nla = nla_find(attrs, attrlen, RTA_ENCAP);
+ if (nla) {
+ struct lwtunnel_state *lwtstate;
+ struct nlattr *nla_entype;
+
+ nla_entype = nla_find(attrs, attrlen,
+ RTA_ENCAP_TYPE);
+ if (!nla_entype) {
+ NL_SET_BAD_ATTR(extack, nla);
+ NL_SET_ERR_MSG(extack,
+ "Encap type is missing");
+ goto err_inval;
+ }
+
+ ret = lwtunnel_build_state(nla_get_u16(
+ nla_entype),
+ nla, AF_INET, cfg,
+ &lwtstate, extack);
+ if (ret)
+ goto errout;
+ nexthop_nh->nh_lwtstate =
+ lwtstate_get(lwtstate);
+ }
+ }
+
+ rtnh = rtnh_next(rtnh, &remaining);
+ } endfor_nexthops(fi);
+
+ return 0;
+
+err_inval:
+ ret = -EINVAL;
+
+errout:
+ return ret;
+}
+
+static void fib_rebalance(struct fib_info *fi)
+{
+ int total;
+ int w;
+ struct in_device *in_dev;
+
+ if (fi->fib_nhs < 2)
+ return;
+
+ total = 0;
+ for_nexthops(fi) {
+ if (nh->nh_flags & RTNH_F_DEAD)
+ continue;
+
+ in_dev = __in_dev_get_rtnl(nh->nh_dev);
+
+ if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ nh->nh_flags & RTNH_F_LINKDOWN)
+ continue;
+
+ total += nh->nh_weight;
+ } endfor_nexthops(fi);
+
+ w = 0;
+ change_nexthops(fi) {
+ int upper_bound;
+
+ in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
+
+ if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
+ upper_bound = -1;
+ } else if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
+ upper_bound = -1;
+ } else {
+ w += nexthop_nh->nh_weight;
+ upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
+ total) - 1;
+ }
+
+ atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
+ } endfor_nexthops(fi);
+}
+#else /* CONFIG_IP_ROUTE_MULTIPATH */
+
+#define fib_rebalance(fi) do { } while (0)
+
+#endif /* CONFIG_IP_ROUTE_MULTIPATH */
+
+static int fib_encap_match(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(encap_type, encap, AF_INET,
+ cfg, &lwtstate, extack);
+ if (!ret) {
+ result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
+ lwtstate_free(lwtstate);
+ }
+
+ return result;
+}
+
+int fib_nh_match(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_oif || cfg->fc_gw) {
+ if (cfg->fc_encap) {
+ if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
+ fi->fib_nh, cfg, extack))
+ return 1;
+ }
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ if (cfg->fc_flow &&
+ cfg->fc_flow != fi->fib_nh->nh_tclassid)
+ return 1;
+#endif
+ 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)
+ 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_in_addr(nla) != nh->nh_gw)
+ return 1;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ 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;
+}
+
+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;
+
+ if (type == RTAX_CC_ALGO) {
+ char tmp[TCP_CA_NAME_MAX];
+ bool ecn_ca = false;
+
+ nla_strlcpy(tmp, nla, sizeof(tmp));
+ val = tcp_ca_get_key_by_name(fi->fib_net, 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;
+}
+
+
+/*
+ * 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_nh *nh,
+ struct netlink_ext_ack *extack)
+{
+ int err = 0;
+ 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) {
+ unsigned int addr_type;
+
+ if (cfg->fc_scope >= RT_SCOPE_LINK) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop has invalid scope");
+ return -EINVAL;
+ }
+ dev = __dev_get_by_index(net, nh->nh_oif);
+ if (!dev)
+ 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->nh_gw);
+ if (addr_type != RTN_UNICAST) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop has invalid gateway");
+ return -EINVAL;
+ }
+ if (!netif_carrier_ok(dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
+ nh->nh_dev = dev;
+ dev_hold(dev);
+ nh->nh_scope = RT_SCOPE_LINK;
+ return 0;
+ }
+ rcu_read_lock();
+ {
+ struct fib_table *tbl = NULL;
+ struct flowi4 fl4 = {
+ .daddr = nh->nh_gw,
+ .flowi4_scope = cfg->fc_scope + 1,
+ .flowi4_oif = nh->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 (cfg->fc_table)
+ tbl = fib_get_table(net, cfg->fc_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");
+ rcu_read_unlock();
+ return err;
+ }
+ }
+ err = -EINVAL;
+ if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
+ NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
+ goto out;
+ }
+ nh->nh_scope = res.scope;
+ nh->nh_oif = FIB_RES_OIF(res);
+ nh->nh_dev = dev = FIB_RES_DEV(res);
+ if (!dev) {
+ NL_SET_ERR_MSG(extack,
+ "No egress device for nexthop gateway");
+ goto out;
+ }
+ dev_hold(dev);
+ if (!netif_carrier_ok(dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
+ err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
+ } else {
+ struct in_device *in_dev;
+
+ if (nh->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->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->nh_dev = in_dev->dev;
+ dev_hold(nh->nh_dev);
+ nh->nh_scope = RT_SCOPE_HOST;
+ if (!netif_carrier_ok(nh->nh_dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
+ err = 0;
+ }
+out:
+ rcu_read_unlock();
+ return err;
+}
+
+static inline unsigned int fib_laddr_hashfn(__be32 val)
+{
+ unsigned int mask = (fib_info_hash_size - 1);
+
+ return ((__force u32)val ^
+ ((__force u32)val >> 7) ^
+ ((__force u32)val >> 14)) & mask;
+}
+
+static struct hlist_head *fib_info_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_info_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_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, bytes;
+
+ spin_lock_bh(&fib_info_lock);
+ old_info_hash = fib_info_hash;
+ old_laddrhash = fib_info_laddrhash;
+ fib_info_hash_size = 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;
+
+ for (i = 0; i < old_size; i++) {
+ struct hlist_head *lhead = &fib_info_laddrhash[i];
+ struct hlist_node *n;
+ struct fib_info *fi;
+
+ hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
+ struct hlist_head *ldest;
+ unsigned int new_hash;
+
+ 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_info_hash_free(old_info_hash, bytes);
+ fib_info_hash_free(old_laddrhash, bytes);
+}
+
+__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
+{
+ nh->nh_saddr = inet_select_addr(nh->nh_dev,
+ nh->nh_gw,
+ nh->nh_parent->fib_scope);
+ nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
+
+ return nh->nh_saddr;
+}
+
+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;
+}
+
+static int
+fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
+{
+ return ip_metrics_convert(fi->fib_net, cfg->fc_mx, cfg->fc_mx_len,
+ fi->fib_metrics->metrics);
+}
+
+struct fib_info *fib_create_info(struct fib_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ int err;
+ struct fib_info *fi = NULL;
+ struct fib_info *ofi;
+ int nhs = 1;
+ struct net *net = cfg->fc_nlinfo.nl_net;
+
+ 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;
+ }
+
+#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;
+ unsigned int bytes;
+
+ if (!new_size)
+ new_size = 16;
+ bytes = new_size * sizeof(struct hlist_head *);
+ new_info_hash = fib_info_hash_alloc(bytes);
+ new_laddrhash = fib_info_hash_alloc(bytes);
+ if (!new_info_hash || !new_laddrhash) {
+ fib_info_hash_free(new_info_hash, bytes);
+ fib_info_hash_free(new_laddrhash, bytes);
+ } else
+ fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
+
+ if (!fib_info_hash_size)
+ goto failure;
+ }
+
+ fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
+ if (!fi)
+ goto failure;
+ if (cfg->fc_mx) {
+ fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
+ if (unlikely(!fi->fib_metrics)) {
+ kfree(fi);
+ return ERR_PTR(err);
+ }
+ refcount_set(&fi->fib_metrics->refcnt, 1);
+ } else {
+ fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
+ }
+ fib_info_cnt++;
+ 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;
+ change_nexthops(fi) {
+ nexthop_nh->nh_parent = fi;
+ nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
+ if (!nexthop_nh->nh_pcpu_rth_output)
+ goto failure;
+ } endfor_nexthops(fi)
+
+ err = fib_convert_metrics(fi, cfg);
+ if (err)
+ goto failure;
+
+ if (cfg->fc_mp) {
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+ err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
+ if (err != 0)
+ goto failure;
+ if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop device index does not match RTA_OIF");
+ goto err_inval;
+ }
+ if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop gateway does not match RTA_GATEWAY");
+ goto err_inval;
+ }
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop class id does not match RTA_FLOW");
+ goto err_inval;
+ }
+#endif
+#else
+ NL_SET_ERR_MSG(extack,
+ "Multipath support not enabled in kernel");
+ goto err_inval;
+#endif
+ } else {
+ struct fib_nh *nh = fi->fib_nh;
+
+ if (cfg->fc_encap) {
+ struct lwtunnel_state *lwtstate;
+
+ if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
+ NL_SET_ERR_MSG(extack,
+ "LWT encap type not specified");
+ goto err_inval;
+ }
+ err = lwtunnel_build_state(cfg->fc_encap_type,
+ cfg->fc_encap, AF_INET, cfg,
+ &lwtstate, extack);
+ if (err)
+ goto failure;
+
+ nh->nh_lwtstate = lwtstate_get(lwtstate);
+ }
+ nh->nh_oif = cfg->fc_oif;
+ nh->nh_gw = cfg->fc_gw;
+ nh->nh_flags = cfg->fc_flags;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ nh->nh_tclassid = cfg->fc_flow;
+ if (nh->nh_tclassid)
+ fi->fib_net->ipv4.fib_num_tclassid_users++;
+#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) {
+ 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 (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->nh_gw) {
+ NL_SET_ERR_MSG(extack,
+ "Route with host scope can not have a gateway");
+ 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)
+ goto failure;
+ } else {
+ int linkdown = 0;
+
+ change_nexthops(fi) {
+ err = fib_check_nh(cfg, nexthop_nh, extack);
+ if (err != 0)
+ goto failure;
+ if (nexthop_nh->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;
+ }
+
+ change_nexthops(fi) {
+ fib_info_update_nh_saddr(net, nexthop_nh);
+ } endfor_nexthops(fi)
+
+ fib_rebalance(fi);
+
+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++;
+ refcount_set(&fi->fib_clntref, 1);
+ 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);
+}
+
+int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
+ u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
+ struct fib_info *fi, unsigned int flags)
+{
+ 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 = 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;
+ if (nla_put_u32(skb, RTA_TABLE, tb_id))
+ goto nla_put_failure;
+ rtm->rtm_type = 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, 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->fib_nhs == 1) {
+ if (fi->fib_nh->nh_gw &&
+ nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
+ goto nla_put_failure;
+ if (fi->fib_nh->nh_oif &&
+ nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
+ goto nla_put_failure;
+ if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
+ struct in_device *in_dev;
+
+ rcu_read_lock();
+ in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
+ if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
+ rtm->rtm_flags |= RTNH_F_DEAD;
+ rcu_read_unlock();
+ }
+ if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
+ rtm->rtm_flags |= RTNH_F_OFFLOAD;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ if (fi->fib_nh[0].nh_tclassid &&
+ nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
+ goto nla_put_failure;
+#endif
+ if (fi->fib_nh->nh_lwtstate &&
+ lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
+ goto nla_put_failure;
+ }
+#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)
+ goto nla_put_failure;
+
+ for_nexthops(fi) {
+ rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
+ if (!rtnh)
+ goto nla_put_failure;
+
+ rtnh->rtnh_flags = nh->nh_flags & 0xFF;
+ if (nh->nh_flags & RTNH_F_LINKDOWN) {
+ struct in_device *in_dev;
+
+ rcu_read_lock();
+ in_dev = __in_dev_get_rcu(nh->nh_dev);
+ if (in_dev &&
+ IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
+ rtnh->rtnh_flags |= RTNH_F_DEAD;
+ rcu_read_unlock();
+ }
+ rtnh->rtnh_hops = nh->nh_weight - 1;
+ rtnh->rtnh_ifindex = nh->nh_oif;
+
+ if (nh->nh_gw &&
+ nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
+ goto nla_put_failure;
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ if (nh->nh_tclassid &&
+ nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
+ goto nla_put_failure;
+#endif
+ if (nh->nh_lwtstate &&
+ lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
+ goto nla_put_failure;
+
+ /* length of rtnetlink header + attributes */
+ rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
+ } endfor_nexthops(fi);
+
+ nla_nest_end(skb, mp);
+ }
+#endif
+ 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 ret = 0;
+ unsigned int hash = fib_laddr_hashfn(local);
+ struct hlist_head *head = &fib_info_laddrhash[hash];
+ struct net *net = dev_net(dev);
+ int tb_id = l3mdev_fib_table(dev);
+ struct fib_info *fi;
+
+ if (!fib_info_laddrhash || local == 0)
+ return 0;
+
+ 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;
+ ret++;
+ }
+ }
+ return ret;
+}
+
+static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
+ enum fib_event_type event_type)
+{
+ struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
+ struct fib_nh_notifier_info info = {
+ .fib_nh = fib_nh,
+ };
+
+ switch (event_type) {
+ case FIB_EVENT_NH_ADD:
+ if (fib_nh->nh_flags & RTNH_F_DEAD)
+ break;
+ if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ fib_nh->nh_flags & RTNH_F_LINKDOWN)
+ break;
+ return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
+ &info.info);
+ case FIB_EVENT_NH_DEL:
+ if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+ fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
+ (fib_nh->nh_flags & RTNH_F_DEAD))
+ return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
+ event_type, &info.info);
+ 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
+ */
+static void nh_update_mtu(struct fib_nh *nh, u32 new, u32 orig)
+{
+ struct fnhe_hash_bucket *bucket;
+ int i;
+
+ bucket = rcu_dereference_protected(nh->nh_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)
+{
+ unsigned int hash = fib_devindex_hashfn(dev->ifindex);
+ struct hlist_head *head = &fib_info_devhash[hash];
+ struct fib_nh *nh;
+
+ hlist_for_each_entry(nh, head, nh_hash) {
+ if (nh->nh_dev == dev)
+ nh_update_mtu(nh, 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
+ */
+int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool 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 fib_nh *nh;
+
+ 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);
+ 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) {
+ switch (event) {
+ case NETDEV_DOWN:
+ case NETDEV_UNREGISTER:
+ nexthop_nh->nh_flags |= RTNH_F_DEAD;
+ /* fall through */
+ case NETDEV_CHANGE:
+ nexthop_nh->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->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;
+ /* fall through */
+ 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;
+ u8 last_tos = 0;
+
+ hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
+ struct fib_info *next_fi = fa->fa_info;
+
+ if (fa->fa_slen != slen)
+ continue;
+ if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
+ continue;
+ if (fa->tb_id != tb->tb_id)
+ continue;
+ if (next_fi->fib_priority > last_prio &&
+ fa->fa_tos == last_tos) {
+ if (last_tos)
+ continue;
+ break;
+ }
+ if (next_fi->fib_flags & RTNH_F_DEAD)
+ continue;
+ last_tos = fa->fa_tos;
+ last_prio = next_fi->fib_priority;
+
+ if (next_fi->fib_scope != res->scope ||
+ fa->fa_type != RTN_UNICAST)
+ continue;
+ if (!next_fi->fib_nh[0].nh_gw ||
+ next_fi->fib_nh[0].nh_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.
+ */
+int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
+{
+ struct fib_info *prev_fi;
+ unsigned int hash;
+ 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;
+ hash = fib_devindex_hashfn(dev->ifindex);
+ head = &fib_info_devhash[hash];
+ ret = 0;
+
+ hlist_for_each_entry(nh, 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 & nh_flags)) {
+ alive++;
+ continue;
+ }
+ if (!nexthop_nh->nh_dev ||
+ !(nexthop_nh->nh_dev->flags & IFF_UP))
+ continue;
+ if (nexthop_nh->nh_dev != dev ||
+ !__in_dev_get_rtnl(dev))
+ continue;
+ alive++;
+ nexthop_nh->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->nh_scope == RT_SCOPE_LINK) {
+ struct neighbour *n;
+
+ rcu_read_lock_bh();
+
+ n = __ipv4_neigh_lookup_noref(nh->nh_dev,
+ (__force u32)nh->nh_gw);
+ if (n)
+ state = n->nud_state;
+
+ rcu_read_unlock_bh();
+ }
+
+ 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;
+
+ for_nexthops(fi) {
+ if (net->ipv4.sysctl_fib_multipath_use_neigh) {
+ if (!fib_good_nh(nh))
+ continue;
+ if (!first) {
+ res->nh_sel = nhsel;
+ first = true;
+ }
+ }
+
+ if (hash > atomic_read(&nh->nh_upper_bound))
+ continue;
+
+ res->nh_sel = nhsel;
+ 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 && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
+ goto check_saddr;
+
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+ if (res->fi->fib_nhs > 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)
+ fl4->saddr = FIB_RES_PREFSRC(net, *res);
+}