[PATCH] net: ipv6: fix TCP early demux

Eric Dumazet
2012-08-06T15:09:38Z

From: Eric Dumazet <edumazet@google.com>

IPv6 needs a cookie in dst_check() call.

We need to add rx_dst_cookie and provide a family independent
sk_rx_dst_set(sk, skb) method to properly support IPv6 TCP early demux.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
Note: we could group sk_rx_dst/rx_dst_ifindex/rx_dst_cookie
in same cache line (in sk)

include/linux/ipv6.h | 1 +
include/net/inet_connection_sock.h | 1 +
include/net/inet_sock.h | 9 ---------
net/ipv4/tcp_input.c | 4 +++-
net/ipv4/tcp_ipv4.c | 13 ++++++++++---
net/ipv4/tcp_minisocks.c | 2 +-
net/ipv6/tcp_ipv6.c | 27 +++++++++++++++++++++++++--
7 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 379e433..879db26 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -369,6 +369,7 @@ struct ipv6_pinfo {
__u8 rcv_tclass;

__u32 dst_cookie;
+ __u32 rx_dst_cookie;

struct ipv6_mc_socklist __rcu *ipv6_mc_list;
struct ipv6_ac_socklist *ipv6_ac_list;
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 5ee66f5..ba1d361 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -39,6 +39,7 @@ struct inet_connection_sock_af_ops {
int (*queue_xmit)(struct sk_buff *skb, struct flowi *fl);
void (*send_check)(struct sock *sk, struct sk_buff *skb);
int (*rebuild_header)(struct sock *sk);
+ void (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
int (*conn_request)(struct sock *sk, struct sk_buff *skb);
struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 83b567f..613cfa4 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -249,13 +249,4 @@ static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
return flags;
}

-static inline void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
-{
- struct dst_entry *dst = skb_dst(skb);
-
- dst_hold(dst);
- sk->sk_rx_dst = dst;
- inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
-}
-
#endif /* _INET_SOCK_H */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2fd2bc9..85308b9 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5392,6 +5392,8 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
{
struct tcp_sock *tp = tcp_sk(sk);

+ if (unlikely(sk->sk_rx_dst == NULL))
+ inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb);
/*
* Header prediction.
* The code loosely follows the one in the famous
@@ -5605,7 +5607,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
tcp_set_state(sk, TCP_ESTABLISHED);

if (skb != NULL) {
- inet_sk_rx_dst_set(sk, skb);
+ icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
security_inet_conn_established(sk, skb);
}

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 42b2a6a..272241f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1627,9 +1627,6 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
sk->sk_rx_dst = NULL;
}
}
- if (unlikely(sk->sk_rx_dst == NULL))
- inet_sk_rx_dst_set(sk, skb);
-
if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
rsk = sk;
goto reset;
@@ -1872,10 +1869,20 @@ static struct timewait_sock_ops tcp_timewait_sock_ops = {
.twsk_destructor= tcp_twsk_destructor,
};

+static void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ dst_hold(dst);
+ sk->sk_rx_dst = dst;
+ inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
+}
+
const struct inet_connection_sock_af_ops ipv4_specific = {
.queue_xmit = ip_queue_xmit,
.send_check = tcp_v4_send_check,
.rebuild_header = inet_sk_rebuild_header,
+ .sk_rx_dst_set = inet_sk_rx_dst_set,
.conn_request = tcp_v4_conn_request,
.syn_recv_sock = tcp_v4_syn_recv_sock,
.net_header_len = sizeof(struct iphdr),
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 232a90c..d9c9dce 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -387,7 +387,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
struct tcp_sock *oldtp = tcp_sk(sk);
struct tcp_cookie_values *oldcvp = oldtp->cookie_values;

- inet_sk_rx_dst_set(newsk, skb);
+ newicsk->icsk_af_ops->sk_rx_dst_set(newsk, skb);

/* TCP Cookie Transactions require space for the cookie pair,
* as it differs for each connection. There is no need to
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c66b90f..5a439e9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1447,7 +1447,17 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
opt_skb = skb_clone(skb, sk_gfp_atomic(sk, GFP_ATOMIC));

if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
+ struct dst_entry *dst = sk->sk_rx_dst;
+
sock_rps_save_rxhash(sk, skb);
+ if (dst) {
+ if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
+ dst->ops->check(dst, np->rx_dst_cookie) == NULL) {
+ dst_release(dst);
+ sk->sk_rx_dst = NULL;
+ }
+ }
+
if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len))
goto reset;
if (opt_skb)
@@ -1705,9 +1715,9 @@ static void tcp_v6_early_demux(struct sk_buff *skb)
struct dst_entry *dst = sk->sk_rx_dst;
struct inet_sock *icsk = inet_sk(sk);
if (dst)
- dst = dst_check(dst, 0);
+ dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
if (dst &&
- icsk->rx_dst_ifindex == inet6_iif(skb))
+ icsk->rx_dst_ifindex == skb->skb_iif)
skb_dst_set_noref(skb, dst);
}
}
@@ -1719,10 +1729,23 @@ static struct timewait_sock_ops tcp6_timewait_sock_ops = {
.twsk_destructor= tcp_twsk_destructor,
};

+static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ const struct rt6_info *rt = (const struct rt6_info *)dst;
+
+ dst_hold(dst);
+ sk->sk_rx_dst = dst;
+ inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
+ if (rt->rt6i_node)
+ inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
+}
+
static const struct inet_connection_sock_af_ops ipv6_specific = {
.queue_xmit = inet6_csk_xmit,
.send_check = tcp_v6_send_check,
.rebuild_header = inet6_sk_rebuild_header,
+ .sk_rx_dst_set = inet6_sk_rx_dst_set,
.conn_request = tcp_v6_conn_request,
.syn_recv_sock = tcp_v6_syn_recv_sock,
.net_header_len = sizeof(struct ipv6hdr),