]> git.kernelconcepts.de Git - karo-tx-linux.git/blobdiff - net/ipv6/route.c
ipv6: introduce ip6_rt_put()
[karo-tx-linux.git] / net / ipv6 / route.c
index 7c7e963260e1792be01a329d4298dc1123c8f738..c1cfcb7e563298db86e555567f7e1e6e33335bce 100644 (file)
@@ -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;
 }
@@ -385,6 +388,69 @@ 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.
  */
@@ -666,7 +732,7 @@ 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 +768,8 @@ 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 +931,8 @@ 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 +948,7 @@ 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 +965,7 @@ 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:
@@ -1507,7 +1576,7 @@ 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 +1587,7 @@ 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 +1673,7 @@ 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;
 }
 
@@ -2249,6 +2318,7 @@ 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 +2396,71 @@ 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 +2470,10 @@ 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 +2485,10 @@ 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 +2732,7 @@ 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;
        }