net: Allow accepted sockets to be bound to l3mdev domain
Allow accepted sockets to derive their sk_bound_dev_if setting from the
l3mdev domain in which the packets originated. A sysctl setting is added
to control the behavior which is similar to sk_mark and
sysctl_tcp_fwmark_accept.
This effectively allow a process to have a "VRF-global" listen socket,
with child sockets bound to the VRF device in which the packet originated.
A similar behavior can be achieved using sk_mark, but a solution using marks
is incomplete as it does not handle duplicate addresses in different L3
domains/VRFs. Allowing sockets to inherit the sk_bound_dev_if from l3mdev
domain provides a complete solution.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 4cbe9f0..643a86c 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -351,7 +351,7 @@
treq->snt_synack.v64 = 0;
treq->tfo_listener = false;
- ireq->ir_iif = sk->sk_bound_dev_if;
+ ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
/* We throwed the options of the initial SYN away, so we hope
* the ACK carries the same options again (see RFC1122 4.2.3.8)
@@ -371,7 +371,7 @@
* hasn't changed since we received the original syn, but I see
* no easy way to do this.
*/
- flowi4_init_output(&fl4, sk->sk_bound_dev_if, ireq->ir_mark,
+ flowi4_init_output(&fl4, ireq->ir_iif, ireq->ir_mark,
RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, IPPROTO_TCP,
inet_sk_flowi_flags(sk),
opt->srr ? opt->faddr : ireq->ir_rmt_addr,
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a0bd7a5..41ff1f8 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -915,6 +915,17 @@
.mode = 0644,
.proc_handler = proc_dointvec,
},
+#ifdef CONFIG_NET_L3_MASTER_DEV
+ {
+ .procname = "tcp_l3mdev_accept",
+ .data = &init_net.ipv4.sysctl_tcp_l3mdev_accept,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+#endif
{
.procname = "tcp_mtu_probing",
.data = &init_net.ipv4.sysctl_tcp_mtu_probing,
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2d656ee..7b1fddc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6204,7 +6204,7 @@
tcp_openreq_init(req, &tmp_opt, skb, sk);
/* Note: tcp_v6_init_req() might override ir_iif for link locals */
- inet_rsk(req)->ir_iif = sk->sk_bound_dev_if;
+ inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb);
af_ops->init_req(req, sk, skb);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 205e674..46e92fb 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1276,6 +1276,7 @@
ireq = inet_rsk(req);
sk_daddr_set(newsk, ireq->ir_rmt_addr);
sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
+ newsk->sk_bound_dev_if = ireq->ir_iif;
newinet->inet_saddr = ireq->ir_loc_addr;
inet_opt = ireq->opt;
rcu_assign_pointer(newinet->inet_opt, inet_opt);