tcp: md5: rcu conversion

In order to be able to support proper RST messages for TCP MD5 flows, we
need to allow access to MD5 keys without locking listener socket.

This conversion is a nice cleanup, and shrinks size of timewait sockets
by 80 bytes.

IPv6 code reuses generic code found in IPv4 instead of duplicating it.

Control path uses GFP_KERNEL allocations instead of GFP_ATOMIC.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Shawn Lu <shawn.lu@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 550e755747e0..3cabafb5cdd1 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -359,13 +359,11 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
                  */
                 do {
                         struct tcp_md5sig_key *key;
-                        memset(tcptw->tw_md5_key, 0, sizeof(tcptw->tw_md5_key));
-                        tcptw->tw_md5_keylen = 0;
+                        tcptw->tw_md5_key = NULL;
                         key = tp->af_specific->md5_lookup(sk, sk);
                         if (key != NULL) {
-                                memcpy(&tcptw->tw_md5_key, key->key, key->keylen);
-                                tcptw->tw_md5_keylen = key->keylen;
-                                if (tcp_alloc_md5sig_pool(sk) == NULL)
+                                tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
+                                if (tcptw->tw_md5_key && tcp_alloc_md5sig_pool(sk) == NULL)
                                         BUG();
                         }
                 } while (0);
@@ -405,8 +403,10 @@ void tcp_twsk_destructor(struct sock *sk)
 {
 #ifdef CONFIG_TCP_MD5SIG
         struct tcp_timewait_sock *twsk = tcp_twsk(sk);
-        if (twsk->tw_md5_keylen)
+        if (twsk->tw_md5_key) {
                 tcp_free_md5sig_pool();
+                kfree_rcu(twsk->tw_md5_key, rcu);
+        }
 #endif
 }
 EXPORT_SYMBOL_GPL(tcp_twsk_destructor);