ipv6: add support of peer address

This patch adds the support of peer address for IPv6. For example, it is
possible to specify the remote end of a 6inY tunnel.
This was already possible in IPv4:
 ip addr add ip1 peer ip2 dev dev1

The peer address is specified with IFA_ADDRESS and the local address with
IFA_LOCAL (like explained in include/uapi/linux/if_addr.h).
Note that the API is not changed, because before this patch, it was not
possible to specify two different addresses in IFA_LOCAL and IFA_REMOTE.
There is a small change for the dump: if the peer is different from ::,
IFA_ADDRESS will contain the peer address instead of the local address.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 100fb8cec17c0157c331fc12366d22f593368295..0727d0e4af3b867129d49f4a183847b177964e05 100644 (file)
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -74,6 +74,7 @@ struct inet6_ifaddr {
        bool                    tokenized;
 
        struct rcu_head         rcu;
+       struct in6_addr         peer_addr;
 };
 
 struct ip6_sf_socklist {

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index d1ab6ab29a55c11e0570bb9854c524d9f21369fc..d684d23bc027f1ebd2574206afa28add3c7f2d27 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2402,6 +2402,7 @@ err_exit:
  *     Manual configuration of address on an interface
  */
 static int inet6_addr_add(struct net *net, int ifindex, const struct in6_addr *pfx,
+                         const struct in6_addr *peer_pfx,
                          unsigned int plen, __u8 ifa_flags, __u32 prefered_lft,
                          __u32 valid_lft)
 {
@@ -2457,6 +2458,8 @@ static int inet6_addr_add(struct net *net, int ifindex, const struct in6_addr *p
                ifp->valid_lft = valid_lft;
                ifp->prefered_lft = prefered_lft;
                ifp->tstamp = jiffies;
+               if (peer_pfx)
+                       ifp->peer_addr = *peer_pfx;
                spin_unlock_bh(&ifp->lock);
 
                addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
@@ -2526,7 +2529,7 @@ int addrconf_add_ifaddr(struct net *net, void __user *arg)
                return -EFAULT;
 
        rtnl_lock();
-       err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr,
+       err = inet6_addr_add(net, ireq.ifr6_ifindex, &ireq.ifr6_addr, NULL,
                             ireq.ifr6_prefixlen, IFA_F_PERMANENT,
                             INFINITY_LIFE_TIME, INFINITY_LIFE_TIME);
        rtnl_unlock();
@@ -3610,18 +3613,20 @@ restart:
        rcu_read_unlock_bh();
 }
 
-static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local)
+static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,
+                                    struct in6_addr **peer_pfx)
 {
        struct in6_addr *pfx = NULL;
 
+       *peer_pfx = NULL;
+
        if (addr)
                pfx = nla_data(addr);
 
        if (local) {
                if (pfx && nla_memcmp(local, pfx, sizeof(*pfx)))
-                       pfx = NULL;
-               else
-                       pfx = nla_data(local);
+                       *peer_pfx = pfx;
+               pfx = nla_data(local);
        }
 
        return pfx;
@@ -3639,7 +3644,7 @@ inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
        struct net *net = sock_net(skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
-       struct in6_addr *pfx;
+       struct in6_addr *pfx, *peer_pfx;
        int err;
 
        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_ipv6_policy);
@@ -3647,7 +3652,7 @@ inet6_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
                return err;
 
        ifm = nlmsg_data(nlh);
-       pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
+       pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
        if (pfx == NULL)
                return -EINVAL;
 
@@ -3705,7 +3710,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
        struct net *net = sock_net(skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
-       struct in6_addr *pfx;
+       struct in6_addr *pfx, *peer_pfx;
        struct inet6_ifaddr *ifa;
        struct net_device *dev;
        u32 valid_lft = INFINITY_LIFE_TIME, preferred_lft = INFINITY_LIFE_TIME;
@@ -3717,7 +3722,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
                return err;
 
        ifm = nlmsg_data(nlh);
-       pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
+       pfx = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer_pfx);
        if (pfx == NULL)
                return -EINVAL;
 
@@ -3745,7 +3750,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
                 * It would be best to check for !NLM_F_CREATE here but
                 * userspace alreay relies on not having to provide this.
                 */
-               return inet6_addr_add(net, ifm->ifa_index, pfx,
+               return inet6_addr_add(net, ifm->ifa_index, pfx, peer_pfx,
                                      ifm->ifa_prefixlen, ifa_flags,
                                      preferred_lft, valid_lft);
        }
@@ -3802,6 +3807,7 @@ static inline int rt_scope(int ifa_scope)
 static inline int inet6_ifaddr_msgsize(void)
 {
        return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
+              + nla_total_size(16) /* IFA_LOCAL */
               + nla_total_size(16) /* IFA_ADDRESS */
               + nla_total_size(sizeof(struct ifa_cacheinfo));
 }
@@ -3840,13 +3846,22 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
                valid = INFINITY_LIFE_TIME;
        }
 
-       if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0 ||
-           put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0) {
-               nlmsg_cancel(skb, nlh);
-               return -EMSGSIZE;
-       }
+       if (ipv6_addr_type(&ifa->peer_addr) != IPV6_ADDR_ANY) {
+               if (nla_put(skb, IFA_LOCAL, 16, &ifa->addr) < 0 ||
+                   nla_put(skb, IFA_ADDRESS, 16, &ifa->peer_addr) < 0)
+                       goto error;
+       } else
+               if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0)
+                       goto error;
+
+       if (put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0)
+               goto error;
 
        return nlmsg_end(skb, nlh);
+
+error:
+       nlmsg_cancel(skb, nlh);
+       return -EMSGSIZE;
 }
 
 static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca,
@@ -4046,7 +4061,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh)
        struct net *net = sock_net(in_skb->sk);
        struct ifaddrmsg *ifm;
        struct nlattr *tb[IFA_MAX+1];
-       struct in6_addr *addr = NULL;
+       struct in6_addr *addr = NULL, *peer;
        struct net_device *dev = NULL;
        struct inet6_ifaddr *ifa;
        struct sk_buff *skb;
@@ -4056,7 +4071,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh)
        if (err < 0)
                goto errout;
 
-       addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL]);
+       addr = extract_addr(tb[IFA_ADDRESS], tb[IFA_LOCAL], &peer);
        if (addr == NULL) {
                err = -EINVAL;
                goto errout;
@@ -4564,11 +4579,26 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
                        ip6_ins_rt(ifp->rt);
                if (ifp->idev->cnf.forwarding)
                        addrconf_join_anycast(ifp);
+               if (ipv6_addr_type(&ifp->peer_addr) != IPV6_ADDR_ANY)
+                       addrconf_prefix_route(&ifp->peer_addr, 128,
+                                             ifp->idev->dev, 0, 0);
                break;
        case RTM_DELADDR:
                if (ifp->idev->cnf.forwarding)
                        addrconf_leave_anycast(ifp);
                addrconf_leave_solict(ifp->idev, &ifp->addr);
+               if (ipv6_addr_type(&ifp->peer_addr) != IPV6_ADDR_ANY) {
+                       struct rt6_info *rt;
+                       struct net_device *dev = ifp->idev->dev;
+
+                       rt = rt6_lookup(dev_net(dev), &ifp->peer_addr, NULL,
+                                       dev->ifindex, 1);
+                       if (rt) {
+                               dst_hold(&rt->dst);
+                               if (ip6_del_rt(rt))
+                                       dst_free(&rt->dst);
+                       }
+               }
                dst_hold(&ifp->rt->dst);
 
                if (ip6_del_rt(ifp->rt))