ipv6: RTA_PREFSRC support for ipv6 route source address selection

[ipv6] Add support for RTA_PREFSRC

This patch allows a user to select the preferred source address
for a specific IPv6-Route. It can be set via a netlink message
setting RTA_PREFSRC to a valid IPv6 address which must be
up on the device the route will be bound to.

Signed-off-by: Daniel Walter <dwalter@barracuda.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index bc3cde0..98348d5 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -42,6 +42,7 @@ struct fib6_config {
 
        struct in6_addr fc_dst;
        struct in6_addr fc_src;
+       struct in6_addr fc_prefsrc;
        struct in6_addr fc_gateway;
 
        unsigned long   fc_expires;
@@ -107,6 +108,7 @@ struct rt6_info {
        struct rt6key                   rt6i_dst ____cacheline_aligned_in_smp;
        u32                             rt6i_flags;
        struct rt6key                   rt6i_src;
+       struct rt6key                   rt6i_prefsrc;
        u32                             rt6i_metric;
        u32                             rt6i_peer_genid;
 

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index c850e5f..86b1cb4 100644 (file)
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -84,6 +84,12 @@ extern int                   ip6_route_add(struct fib6_config *cfg);
 extern int                     ip6_ins_rt(struct rt6_info *);
 extern int                     ip6_del_rt(struct rt6_info *);
 
+extern int                     ip6_route_get_saddr(struct net *net,
+                                                   struct rt6_info *rt,
+                                                   struct in6_addr *daddr,
+                                                   unsigned int prefs,
+                                                   struct in6_addr *saddr);
+
 extern struct rt6_info         *rt6_lookup(struct net *net,
                                            const struct in6_addr *daddr,
                                            const struct in6_addr *saddr,
@@ -141,6 +147,7 @@ struct rt6_rtnl_dump_arg {
 extern int rt6_dump_route(struct rt6_info *rt, void *p_arg);
 extern void rt6_ifdown(struct net *net, struct net_device *dev);
 extern void rt6_mtu_change(struct net_device *dev, unsigned mtu);
+extern void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
 
 
 /*

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1493534..129d7e1 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -825,6 +825,8 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
                dst_release(&rt->dst);
        }
 
+       /* clean up prefsrc entries */
+       rt6_remove_prefsrc(ifp);
 out:
        in6_ifa_put(ifp);
 }

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 46cf7be..c614d02 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -930,10 +930,10 @@ static int ip6_dst_lookup_tail(struct sock *sk,
                goto out_err_release;
 
        if (ipv6_addr_any(&fl6->saddr)) {
-               err = ipv6_dev_get_saddr(net, ip6_dst_idev(*dst)->dev,
-                                        &fl6->daddr,
-                                        sk ? inet6_sk(sk)->srcprefs : 0,
-                                        &fl6->saddr);
+               struct rt6_info *rt = (struct rt6_info *) *dst;
+               err = ip6_route_get_saddr(net, rt, &fl6->daddr,
+                                         sk ? inet6_sk(sk)->srcprefs : 0,
+                                         &fl6->saddr);
                if (err)
                        goto out_err_release;
        }

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 843406f..af26cc1 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1325,6 +1325,16 @@ int ip6_route_add(struct fib6_config *cfg)
        if (dev == NULL)
                goto out;
 
+       if (!ipv6_addr_any(&cfg->fc_prefsrc)) {
+               if (!ipv6_chk_addr(net, &cfg->fc_prefsrc, dev, 0)) {
+                       err = -EINVAL;
+                       goto out;
+               }
+               ipv6_addr_copy(&rt->rt6i_prefsrc.addr, &cfg->fc_prefsrc);
+               rt->rt6i_prefsrc.plen = 128;
+       } else
+               rt->rt6i_prefsrc.plen = 0;
+
        if (cfg->fc_flags & (RTF_GATEWAY | RTF_NONEXTHOP)) {
                rt->rt6i_nexthop = __neigh_lookup_errno(&nd_tbl, &rt->rt6i_gateway, dev);
                if (IS_ERR(rt->rt6i_nexthop)) {
@@ -2037,6 +2047,55 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
        return rt;
 }
 
+int ip6_route_get_saddr(struct net *net,
+                       struct rt6_info *rt,
+                       struct in6_addr *daddr,
+                       unsigned int prefs,
+                       struct in6_addr *saddr)
+{
+       struct inet6_dev *idev = ip6_dst_idev((struct dst_entry*)rt);
+       int err = 0;
+       if (rt->rt6i_prefsrc.plen)
+               ipv6_addr_copy(saddr, &rt->rt6i_prefsrc.addr);
+       else
+               err = ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,
+                                        daddr, prefs, saddr);
+       return err;
+}
+
+/* remove deleted ip from prefsrc entries */
+struct arg_dev_net_ip {
+       struct net_device *dev;
+       struct net *net;
+       struct in6_addr *addr;
+};
+
+static int fib6_remove_prefsrc(struct rt6_info *rt, void *arg)
+{
+       struct net_device *dev = ((struct arg_dev_net_ip *)arg)->dev;
+       struct net *net = ((struct arg_dev_net_ip *)arg)->net;
+       struct in6_addr *addr = ((struct arg_dev_net_ip *)arg)->addr;
+
+       if (((void *)rt->rt6i_dev == dev || dev == NULL) &&
+           rt != net->ipv6.ip6_null_entry &&
+           ipv6_addr_equal(addr, &rt->rt6i_prefsrc.addr)) {
+               /* remove prefsrc entry */
+               rt->rt6i_prefsrc.plen = 0;
+       }
+       return 0;
+}
+
+void rt6_remove_prefsrc(struct inet6_ifaddr *ifp)
+{
+       struct net *net = dev_net(ifp->idev->dev);
+       struct arg_dev_net_ip adni = {
+               .dev = ifp->idev->dev,
+               .net = net,
+               .addr = &ifp->addr,
+       };
+       fib6_clean_all(net, fib6_remove_prefsrc, 0, &adni);
+}
+
 struct arg_dev_net {
        struct net_device *dev;
        struct net *net;
@@ -2183,6 +2242,9 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
                nla_memcpy(&cfg->fc_src, tb[RTA_SRC], plen);
        }
 
+       if (tb[RTA_PREFSRC])
+               nla_memcpy(&cfg->fc_prefsrc, tb[RTA_PREFSRC], 16);
+
        if (tb[RTA_OIF])
                cfg->fc_ifindex = nla_get_u32(tb[RTA_OIF]);
 
@@ -2325,13 +2387,17 @@ static int rt6_fill_node(struct net *net,
 #endif
                        NLA_PUT_U32(skb, RTA_IIF, iif);
        } else if (dst) {
-               struct inet6_dev *idev = ip6_dst_idev(&rt->dst);
                struct in6_addr saddr_buf;
-               if (ipv6_dev_get_saddr(net, idev ? idev->dev : NULL,
-                                      dst, 0, &saddr_buf) == 0)
+               if (ip6_route_get_saddr(net, rt, dst, 0, &saddr_buf) == 0)
                        NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
        }
 
+       if (rt->rt6i_prefsrc.plen) {
+               struct in6_addr saddr_buf;
+               ipv6_addr_copy(&saddr_buf, &rt->rt6i_prefsrc.addr);
+               NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
+       }
+
        if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
                goto nla_put_failure;