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Date: Wed, 12 Feb 2020 09:30:36 +0100
From: William Dauchy <w.dauchy@...teo.com>
To: netdev@...r.kernel.org
Cc: nicolas.dichtel@...nd.com, William Dauchy <w.dauchy@...teo.com>
Subject: [PATCH v3 net] 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@...E: <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@...0: <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@...E: <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: William Dauchy <w.dauchy@...teo.com>
---
net/ipv6/ip6_tunnel.c | 55 ++++++++++++++++++++++++++++++++-----------
1 file changed, 41 insertions(+), 14 deletions(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b5dd20c4599b..e57802f100fd 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -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);
@@ -1823,6 +1844,7 @@ static void ip6_tnl_dev_setup(struct net_device *dev)
static inline int
ip6_tnl_dev_init_gen(struct net_device *dev)
{
+ struct net_device *tdev = NULL;
struct ip6_tnl *t = netdev_priv(dev);
int ret;
int t_hlen;
@@ -1848,6 +1870,11 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
dev->type = ARPHRD_TUNNEL6;
dev->hard_header_len = LL_MAX_HEADER + t_hlen;
dev->mtu = ETH_DATA_LEN - t_hlen;
+ if (t->parms.link) {
+ tdev = __dev_get_by_index(t->net, t->parms.link);
+ if (tdev && tdev->mtu < dev->mtu)
+ dev->mtu = tdev->mtu;
+ }
if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
dev->mtu -= 8;
dev->min_mtu = ETH_MIN_MTU;
--
2.25.0
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