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Message-Id: <20200213153552.330380-1-w.dauchy@criteo.com>
Date: Thu, 13 Feb 2020 16:35:52 +0100
From: William Dauchy <w.dauchy@...teo.com>
To: netdev@...r.kernel.org
Cc: William Dauchy <w.dauchy@...teo.com>,
Nicolas Dichtel <nicolas.dichtel@...nd.com>
Subject: [PATCH v4 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>
---
changes in v2:
- splitted code to differenciate link/type check
changes in v3:
- abadon 2/2 with type check as we do not have any real use case as of
today
- fix lookup function and mtu calculation
changes in v4:
- fix and move mtu calculation in ip6_tnl_link_config
---
net/ipv6/ip6_tunnel.c | 69 +++++++++++++++++++++++++++++--------------
1 file changed, 47 insertions(+), 22 deletions(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b5dd20c4599b..284e24806eab 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);
@@ -1420,9 +1441,11 @@ ip6_tnl_start_xmit(struct sk_buff *skb, struct net_device *dev)
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;
int t_hlen;
+ int mtu;
memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
@@ -1457,22 +1480,24 @@ 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 (!IS_ERR(rt)) {
+ tdev = rt->dst.dev;
+ ip6_rt_put(rt);
+ } else if (t->parms.link) {
+ tdev = __dev_get_by_index(t->net, t->parms.link);
+ }
- if (!rt)
- return;
-
- 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(tdev->mtu, IP_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);
}
}
--
2.25.0
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