From b6f9083b0d96aeb29cffed8d68d3a595c51e2f02 Mon Sep 17 00:00:00 2001 From: William Dauchy Date: Thu, 13 Feb 2020 18:19:22 +0100 Subject: [PATCH] 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: 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: 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: 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 Reviewed-by: Nicolas Dichtel Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 68 ++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 21 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index b5dd20c4599bb..5d65436ad5adf 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); @@ -1420,8 +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); } } -- 2.39.5