1 files changed, 163 insertions, 47 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index b1e6cf0..e229a3b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -57,6 +57,7 @@
 #include <net/xfrm.h>
 #include <net/netevent.h>
 #include <net/netlink.h>
+#include <net/nexthop.h>
 
 #include <asm/uaccess.h>
 
@@ -289,6 +290,8 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net,
 		memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst));
 		rt6_init_peer(rt, table ? &table->tb6_peers : net->ipv6.peers);
 		rt->rt6i_genid = rt_genid(net);
+		INIT_LIST_HEAD(&rt->rt6i_siblings);
+		rt->rt6i_nsiblings = 0;
 	}
 	return rt;
 }
@@ -318,13 +321,6 @@ static void ip6_dst_destroy(struct dst_entry *dst)
 	}
 }
 
-static atomic_t __rt6_peer_genid = ATOMIC_INIT(0);
-
-static u32 rt6_peer_genid(void)
-{
-	return atomic_read(&__rt6_peer_genid);
-}
-
 void rt6_bind_peer(struct rt6_info *rt, int create)
 {
 	struct inet_peer_base *base;
@@ -338,8 +334,6 @@ void rt6_bind_peer(struct rt6_info *rt, int create)
 	if (peer) {
 		if (!rt6_set_peer(rt, peer))
 			inet_putpeer(peer);
-		else
-			rt->rt6i_peer_genid = rt6_peer_genid();
 	}
 }
 
@@ -385,6 +379,69 @@ static bool rt6_need_strict(const struct in6_addr *daddr)
 		(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
 }
 
+/* Multipath route selection:
+ *   Hash based function using packet header and flowlabel.
+ * Adapted from fib_info_hashfn()
+ */
+static int rt6_info_hash_nhsfn(unsigned int candidate_count,
+			       const struct flowi6 *fl6)
+{
+	unsigned int val = fl6->flowi6_proto;
+
+	val ^= (__force u32)fl6->daddr.s6_addr32[0];
+	val ^= (__force u32)fl6->daddr.s6_addr32[1];
+	val ^= (__force u32)fl6->daddr.s6_addr32[2];
+	val ^= (__force u32)fl6->daddr.s6_addr32[3];
+
+	val ^= (__force u32)fl6->saddr.s6_addr32[0];
+	val ^= (__force u32)fl6->saddr.s6_addr32[1];
+	val ^= (__force u32)fl6->saddr.s6_addr32[2];
+	val ^= (__force u32)fl6->saddr.s6_addr32[3];
+
+	/* Work only if this not encapsulated */
+	switch (fl6->flowi6_proto) {
+	case IPPROTO_UDP:
+	case IPPROTO_TCP:
+	case IPPROTO_SCTP:
+		val ^= (__force u16)fl6->fl6_sport;
+		val ^= (__force u16)fl6->fl6_dport;
+		break;
+
+	case IPPROTO_ICMPV6:
+		val ^= (__force u16)fl6->fl6_icmp_type;
+		val ^= (__force u16)fl6->fl6_icmp_code;
+		break;
+	}
+	/* RFC6438 recommands to use flowlabel */
+	val ^= (__force u32)fl6->flowlabel;
+
+	/* Perhaps, we need to tune, this function? */
+	val = val ^ (val >> 7) ^ (val >> 12);
+	return val % candidate_count;
+}
+
+static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
+					     struct flowi6 *fl6)
+{
+	struct rt6_info *sibling, *next_sibling;
+	int route_choosen;
+
+	route_choosen = rt6_info_hash_nhsfn(match->rt6i_nsiblings + 1, fl6);
+	/* Don't change the route, if route_choosen == 0
+	 * (siblings does not include ourself)
+	 */
+	if (route_choosen)
+		list_for_each_entry_safe(sibling, next_sibling,
+				&match->rt6i_siblings, rt6i_siblings) {
+			route_choosen--;
+			if (route_choosen == 0) {
+				match = sibling;
+				break;
+			}
+		}
+	return match;
+}
+
 /*
  *	Route lookup. Any table->tb6_lock is implied.
  */
@@ -487,35 +544,32 @@ static inline int rt6_check_dev(struct rt6_info *rt, int oif)
 	return 0;
 }
 
-static inline int rt6_check_neigh(struct rt6_info *rt)
+static inline bool rt6_check_neigh(struct rt6_info *rt)
 {
 	struct neighbour *neigh;
-	int m;
+	bool ret = false;
 
 	neigh = rt->n;
 	if (rt->rt6i_flags & RTF_NONEXTHOP ||
 	    !(rt->rt6i_flags & RTF_GATEWAY))
-		m = 1;
+		ret = true;
 	else if (neigh) {
 		read_lock_bh(&neigh->lock);
 		if (neigh->nud_state & NUD_VALID)
-			m = 2;
+			ret = true;
 #ifdef CONFIG_IPV6_ROUTER_PREF
-		else if (neigh->nud_state & NUD_FAILED)
-			m = 0;
+		else if (!(neigh->nud_state & NUD_FAILED))
+			ret = true;
 #endif
-		else
-			m = 1;
 		read_unlock_bh(&neigh->lock);
-	} else
-		m = 0;
-	return m;
+	}
+	return ret;
 }
 
 static int rt6_score_route(struct rt6_info *rt, int oif,
 			   int strict)
 {
-	int m, n;
+	int m;
 
 	m = rt6_check_dev(rt, oif);
 	if (!m && (strict & RT6_LOOKUP_F_IFACE))
@@ -523,8 +577,7 @@ static int rt6_score_route(struct rt6_info *rt, int oif,
 #ifdef CONFIG_IPV6_ROUTER_PREF
 	m |= IPV6_DECODE_PREF(IPV6_EXTRACT_PREF(rt->rt6i_flags)) << 2;
 #endif
-	n = rt6_check_neigh(rt);
-	if (!n && (strict & RT6_LOOKUP_F_REACHABLE))
+	if (!rt6_check_neigh(rt) && (strict & RT6_LOOKUP_F_REACHABLE))
 		return -1;
 	return m;
 }
@@ -666,7 +719,7 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
 		else
 			rt6_set_expires(rt, jiffies + HZ * lifetime);
 
-		dst_release(&rt->dst);
+		ip6_rt_put(rt);
 	}
 	return 0;
 }
@@ -702,6 +755,8 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net,
 restart:
 	rt = fn->leaf;
 	rt = rt6_device_match(net, rt, &fl6->saddr, fl6->flowi6_oif, flags);
+	if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
+		rt = rt6_multipath_select(rt, fl6);
 	BACKTRACK(net, &fl6->saddr);
 out:
 	dst_use(&rt->dst, jiffies);
@@ -863,7 +918,8 @@ restart_2:
 
 restart:
 	rt = rt6_select(fn, oif, strict | reachable);
-
+	if (rt->rt6i_nsiblings && oif == 0)
+		rt = rt6_multipath_select(rt, fl6);
 	BACKTRACK(net, &fl6->saddr);
 	if (rt == net->ipv6.ip6_null_entry ||
 	    rt->rt6i_flags & RTF_CACHE)
@@ -879,7 +935,7 @@ restart:
 	else
 		goto out2;
 
-	dst_release(&rt->dst);
+	ip6_rt_put(rt);
 	rt = nrt ? : net->ipv6.ip6_null_entry;
 
 	dst_hold(&rt->dst);
@@ -896,7 +952,7 @@ restart:
 	 * Race condition! In the gap, when table->tb6_lock was
 	 * released someone could insert this route.  Relookup.
 	 */
-	dst_release(&rt->dst);
+	ip6_rt_put(rt);
 	goto relookup;
 
 out:
@@ -1030,14 +1086,9 @@ static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
 	if (rt->rt6i_genid != rt_genid(dev_net(rt->dst.dev)))
 		return NULL;
 
-	if (rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie)) {
-		if (rt->rt6i_peer_genid != rt6_peer_genid()) {
-			if (!rt6_has_peer(rt))
-				rt6_bind_peer(rt, 0);
-			rt->rt6i_peer_genid = rt6_peer_genid();
-		}
+	if (rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie))
 		return dst;
-	}
+
 	return NULL;
 }
 
@@ -1316,12 +1367,6 @@ out:
 	return entries > rt_max_size;
 }
 
-/* Clean host part of a prefix. Not necessary in radix tree,
-   but results in cleaner routing tables.
-
-   Remove it only when all the things will work!
- */
-
 int ip6_dst_hoplimit(struct dst_entry *dst)
 {
 	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
@@ -1507,7 +1552,7 @@ int ip6_route_add(struct fib6_config *cfg)
 				goto out;
 			if (dev) {
 				if (dev != grt->dst.dev) {
-					dst_release(&grt->dst);
+					ip6_rt_put(grt);
 					goto out;
 				}
 			} else {
@@ -1518,7 +1563,7 @@ int ip6_route_add(struct fib6_config *cfg)
 			}
 			if (!(grt->rt6i_flags & RTF_GATEWAY))
 				err = 0;
-			dst_release(&grt->dst);
+			ip6_rt_put(grt);
 
 			if (err)
 				goto out;
@@ -1604,7 +1649,7 @@ static int __ip6_del_rt(struct rt6_info *rt, struct nl_info *info)
 	write_unlock_bh(&table->tb6_lock);
 
 out:
-	dst_release(&rt->dst);
+	ip6_rt_put(rt);
 	return err;
 }
 
@@ -1987,7 +2032,7 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 	switch(cmd) {
 	case SIOCADDRT:		/* Add a route */
 	case SIOCDELRT:		/* Delete a route */
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			return -EPERM;
 		err = copy_from_user(&rtmsg, arg,
 				     sizeof(struct in6_rtmsg));
@@ -2249,6 +2294,7 @@ static const struct nla_policy rtm_ipv6_policy[RTA_MAX+1] = {
 	[RTA_IIF]		= { .type = NLA_U32 },
 	[RTA_PRIORITY]          = { .type = NLA_U32 },
 	[RTA_METRICS]           = { .type = NLA_NESTED },
+	[RTA_MULTIPATH]		= { .len = sizeof(struct rtnexthop) },
 };
 
 static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -2326,11 +2372,71 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (tb[RTA_TABLE])
 		cfg->fc_table = nla_get_u32(tb[RTA_TABLE]);
 
+	if (tb[RTA_MULTIPATH]) {
+		cfg->fc_mp = nla_data(tb[RTA_MULTIPATH]);
+		cfg->fc_mp_len = nla_len(tb[RTA_MULTIPATH]);
+	}
+
 	err = 0;
 errout:
 	return err;
 }
 
+static int ip6_route_multipath(struct fib6_config *cfg, int add)
+{
+	struct fib6_config r_cfg;
+	struct rtnexthop *rtnh;
+	int remaining;
+	int attrlen;
+	int err = 0, last_err = 0;
+
+beginning:
+	rtnh = (struct rtnexthop *)cfg->fc_mp;
+	remaining = cfg->fc_mp_len;
+
+	/* Parse a Multipath Entry */
+	while (rtnh_ok(rtnh, remaining)) {
+		memcpy(&r_cfg, cfg, sizeof(*cfg));
+		if (rtnh->rtnh_ifindex)
+			r_cfg.fc_ifindex = rtnh->rtnh_ifindex;
+
+		attrlen = rtnh_attrlen(rtnh);
+		if (attrlen > 0) {
+			struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
+
+			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
+			if (nla) {
+				nla_memcpy(&r_cfg.fc_gateway, nla, 16);
+				r_cfg.fc_flags |= RTF_GATEWAY;
+			}
+		}
+		err = add ? ip6_route_add(&r_cfg) : ip6_route_del(&r_cfg);
+		if (err) {
+			last_err = err;
+			/* If we are trying to remove a route, do not stop the
+			 * loop when ip6_route_del() fails (because next hop is
+			 * already gone), we should try to remove all next hops.
+			 */
+			if (add) {
+				/* If add fails, we should try to delete all
+				 * next hops that have been already added.
+				 */
+				add = 0;
+				goto beginning;
+			}
+		}
+		/* Because each route is added like a single route we remove
+		 * this flag after the first nexthop (if there is a collision,
+		 * we have already fail to add the first nexthop:
+		 * fib6_add_rt2node() has reject it).
+		 */
+		cfg->fc_nlinfo.nlh->nlmsg_flags &= ~NLM_F_EXCL;
+		rtnh = rtnh_next(rtnh, &remaining);
+	}
+
+	return last_err;
+}
+
 static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 {
 	struct fib6_config cfg;
@@ -2340,7 +2446,10 @@ static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *a
 	if (err < 0)
 		return err;
 
-	return ip6_route_del(&cfg);
+	if (cfg.fc_mp)
+		return ip6_route_multipath(&cfg, 0);
+	else
+		return ip6_route_del(&cfg);
 }
 
 static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
@@ -2352,7 +2461,10 @@ static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *a
 	if (err < 0)
 		return err;
 
-	return ip6_route_add(&cfg);
+	if (cfg.fc_mp)
+		return ip6_route_multipath(&cfg, 1);
+	else
+		return ip6_route_add(&cfg);
 }
 
 static inline size_t rt6_nlmsg_size(void)
@@ -2596,7 +2708,7 @@ static int inet6_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void
 
 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (!skb) {
-		dst_release(&rt->dst);
+		ip6_rt_put(rt);
 		err = -ENOBUFS;
 		goto errout;
 	}
@@ -2873,6 +2985,10 @@ struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
 		table[7].data = &net->ipv6.sysctl.ip6_rt_mtu_expires;
 		table[8].data = &net->ipv6.sysctl.ip6_rt_min_advmss;
 		table[9].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
+
+		/* Don't export sysctls to unprivileged users */
+		if (net->user_ns != &init_user_ns)
+			table[0].procname = NULL;
 	}
 
 	return table;