Commit 5fdcce21 authored by William Dauchy's avatar William Dauchy Committed by David S. Miller
Browse files

net, ip6_tunnel: enhance tunnel locate with link check 



With ipip, it is possible to create an extra interface explicitly
attached to a given physical interface:

  # ip link show tunl0
  4: tunl0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0
  # ip link add tunl1 type ipip dev eth0
  # ip link show tunl1
  6: tunl1@eth0: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ipip 0.0.0.0 brd 0.0.0.0

But it is not possible with ip6tnl:

  # ip link show ip6tnl0
  5: ip6tnl0@NONE: <NOARP> mtu 1452 qdisc noop state DOWN mode DEFAULT group default qlen 1000
      link/tunnel6 :: brd ::
  # ip link add ip6tnl1 type ip6tnl dev eth0
  RTNETLINK answers: File exists

This patch aims to make it possible by adding link comparaison in both
tunnel locate and lookup functions; we also modify mtu calculation when
attached to an interface with a lower mtu.

This permits to make use of x-netns communication by moving the newly
created tunnel in a given netns.

Signed-off-by: default avatarWilliam Dauchy <w.dauchy@criteo.com>
Reviewed-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b32cb6fc

net/ipv6/ip6_tunnel.c

+47 −21
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev) 


/**

 * ip6_tnl_lookup - fetch tunnel matching the end-point addresses

 *   @link: ifindex of underlying interface

 *   @remote: the address of the tunnel exit-point

 *   @local: the address of the tunnel entry-point

 *
@@ -134,37 +135,56 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev) 
	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))



static struct ip6_tnl *

ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)

ip6_tnl_lookup(struct net *net, int link,

	       const struct in6_addr *remote, const struct in6_addr *local)

{

	unsigned int hash = HASH(remote, local);

	struct ip6_tnl *t;

	struct ip6_tnl *t, *cand = NULL;

	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);

	struct in6_addr any;



	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {

		if (ipv6_addr_equal(local, &t->parms.laddr) &&

		    ipv6_addr_equal(remote, &t->parms.raddr) &&

		    (t->dev->flags & IFF_UP))

		if (!ipv6_addr_equal(local, &t->parms.laddr) ||

		    !ipv6_addr_equal(remote, &t->parms.raddr) ||

		    !(t->dev->flags & IFF_UP))

			continue;



		if (link == t->parms.link)

			return t;

		else

			cand = t;

	}



	memset(&any, 0, sizeof(any));

	hash = HASH(&any, local);

	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {

		if (ipv6_addr_equal(local, &t->parms.laddr) &&

		    ipv6_addr_any(&t->parms.raddr) &&

		    (t->dev->flags & IFF_UP))

		if (!ipv6_addr_equal(local, &t->parms.laddr) ||

		    !ipv6_addr_any(&t->parms.raddr) ||

		    !(t->dev->flags & IFF_UP))

			continue;



		if (link == t->parms.link)

			return t;

		else if (!cand)

			cand = t;

	}



	hash = HASH(remote, &any);

	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {

		if (ipv6_addr_equal(remote, &t->parms.raddr) &&

		    ipv6_addr_any(&t->parms.laddr) &&

		    (t->dev->flags & IFF_UP))

		if (!ipv6_addr_equal(remote, &t->parms.raddr) ||

		    !ipv6_addr_any(&t->parms.laddr) ||

		    !(t->dev->flags & IFF_UP))

			continue;



		if (link == t->parms.link)

			return t;

		else if (!cand)

			cand = t;

	}



	if (cand)

		return cand;



	t = rcu_dereference(ip6n->collect_md_tun);

	if (t && t->dev->flags & IFF_UP)

		return t;
@@ -351,7 +371,8 @@ static struct ip6_tnl *ip6_tnl_locate(struct net *net, 
	     (t = rtnl_dereference(*tp)) != NULL;

	     tp = &t->next) {

		if (ipv6_addr_equal(local, &t->parms.laddr) &&

		    ipv6_addr_equal(remote, &t->parms.raddr)) {

		    ipv6_addr_equal(remote, &t->parms.raddr) &&

		    p->link == t->parms.link) {

			if (create)

				return ERR_PTR(-EEXIST);
@@ -485,7 +506,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt, 
	   processing of the error. */



	rcu_read_lock();

	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr, &ipv6h->saddr);

	t = ip6_tnl_lookup(dev_net(skb->dev), skb->dev->ifindex, &ipv6h->daddr, &ipv6h->saddr);

	if (!t)

		goto out;
@@ -887,7 +908,7 @@ static int ipxip6_rcv(struct sk_buff *skb, u8 ipproto, 
	int ret = -1;



	rcu_read_lock();

	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);

	t = ip6_tnl_lookup(dev_net(skb->dev), skb->dev->ifindex, &ipv6h->saddr, &ipv6h->daddr);



	if (t) {

		u8 tproto = READ_ONCE(t->parms.proto);
@@ -1420,8 +1441,10 @@ tx_err: 
static void ip6_tnl_link_config(struct ip6_tnl *t)

{

	struct net_device *dev = t->dev;

	struct net_device *tdev = NULL;

	struct __ip6_tnl_parm *p = &t->parms;

	struct flowi6 *fl6 = &t->fl.u.ip6;

	unsigned int mtu;

	int t_hlen;



	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
@@ -1457,22 +1480,25 @@ static void ip6_tnl_link_config(struct ip6_tnl *t) 
		struct rt6_info *rt = rt6_lookup(t->net,

						 &p->raddr, &p->laddr,

						 p->link, NULL, strict);

		if (rt) {

			tdev = rt->dst.dev;

			ip6_rt_put(rt);

		}



		if (!rt)

			return;

		if (!tdev && p->link)

			tdev = __dev_get_by_index(t->net, p->link);



		if (rt->dst.dev) {

			dev->hard_header_len = rt->dst.dev->hard_header_len +

				t_hlen;

		if (tdev) {

			dev->hard_header_len = tdev->hard_header_len + t_hlen;

			mtu = min_t(unsigned int, tdev->mtu, IP6_MAX_MTU);



			dev->mtu = rt->dst.dev->mtu - t_hlen;

			dev->mtu = mtu - t_hlen;

			if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))

				dev->mtu -= 8;



			if (dev->mtu < IPV6_MIN_MTU)

				dev->mtu = IPV6_MIN_MTU;

		}

		ip6_rt_put(rt);

	}

}

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