Thread (7 messages) 7 messages, 2 authors, 2013-05-19
STALE4784d

[RESEND PATCH net-next v2] ipv6: add support of peer address

From: Nicolas Dichtel <hidden>
Date: 2013-05-17 08:32:12
Subsystem: networking [general], networking [ipv4/ipv6], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds

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 <redacted>
---

Note that iproute2 is already able to add addr like this (but needs a small
fix for the display, I will send it when the patch is merged):
$ ip tunnel add mode sit remote 192.168.123.2 local 192.168.123.1
$ ip -6 addr add 2003::1 peer 2003::2 dev sit1
$ ip addr list dev sit1
6: sit1: <POINTOPOINT,NOARP> mtu 1480 qdisc noop state DOWN
    link/sit 192.168.123.1 peer 192.168.123.2
    inet6 2003::1 peer 2003::2/128 scope global
       valid_lft forever preferred_lft forever

Now that net-next is open, I resend the v2.
v2: fix skb size calculation in inet6_ifaddr_msgsize()

 include/net/if_inet6.h |  1 +
 net/ipv6/addrconf.c    | 64 ++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 48 insertions(+), 17 deletions(-)
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 100fb8c..0727d0e 100644
--- 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 d1ab6ab..d684d23 100644
--- 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))
-- 
1.8.2.1
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