[PATCH v2 net-next 3/5] tcp: md5: input path is run under rcu protected sections

Eric Dumazet
2015-03-24T22:59:27Z

It is guaranteed that both tcp_v4_rcv() and tcp_v6_rcv()
run from rcu read locked sections :

ip_local_deliver_finish() and ip6_input_finish() both
use rcu_read_lock()

Also align tcp_v6_inbound_md5_hash() on tcp_v4_inbound_md5_hash()
by returning a boolean.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/tcp_ipv4.c | 17 +++--------------
net/ipv6/tcp_ipv6.c | 25 ++++++-------------------
2 files changed, 9 insertions(+), 33 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4e90217003e8..d339a0488f51 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1153,8 +1153,9 @@ clear_hash_noput:
}
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);

-static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
- const struct sk_buff *skb)
+/* Called with rcu_read_lock() */
+static bool tcp_v4_inbound_md5_hash(struct sock *sk,
+ const struct sk_buff *skb)
{
/*
* This gets called for each TCP segment that arrives
@@ -1206,18 +1207,6 @@ static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
}
return false;
}
-
-static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
-{
- bool ret;
-
- rcu_read_lock();
- ret = __tcp_v4_inbound_md5_hash(sk, skb);
- rcu_read_unlock();
-
- return ret;
-}
-
#endif

static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 4a4e6d30c448..078e7d0f4cd8 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -633,8 +633,7 @@ clear_hash_noput:
return 1;
}

-static int __tcp_v6_inbound_md5_hash(struct sock *sk,
- const struct sk_buff *skb)
+static bool tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
{
const __u8 *hash_location = NULL;
struct tcp_md5sig_key *hash_expected;
@@ -648,16 +647,16 @@ static int __tcp_v6_inbound_md5_hash(struct sock *sk,

/* We've parsed the options - do we have a hash? */
if (!hash_expected && !hash_location)
- return 0;
+ return false;

if (hash_expected && !hash_location) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
- return 1;
+ return true;
}

if (!hash_expected && hash_location) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
- return 1;
+ return true;
}

/* check the signature */
@@ -670,22 +669,10 @@ static int __tcp_v6_inbound_md5_hash(struct sock *sk,
genhash ? "failed" : "mismatch",
&ip6h->saddr, ntohs(th->source),
&ip6h->daddr, ntohs(th->dest));
- return 1;
+ return true;
}
- return 0;
-}
-
-static int tcp_v6_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
-{
- int ret;
-
- rcu_read_lock();
- ret = __tcp_v6_inbound_md5_hash(sk, skb);
- rcu_read_unlock();
-
- return ret;
+ return false;
}
-
#endif

static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
--
2.2.0.rc0.207.ga3a616c