net/tcp: Add TCP-AO sign to twsk

Add support for sockets in time-wait state.
ao_info as well as all keys are inherited on transition to time-wait
socket. The lifetime of ao_info is now protected by ref counter, so
that tcp_ao_destroy_sock() will destruct it only when the last user is
gone.

Co-developed-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Co-developed-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 8 deletions

diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index b8afe78ff057..7c4e2f42845a 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -159,6 +159,7 @@ static struct tcp_ao_info *tcp_ao_alloc_info(gfp_t flags)
 	if (!ao)
 		return NULL;
 	INIT_HLIST_HEAD(&ao->head);
+	refcount_set(&ao->refcnt, 1);
 
 	return ao;
 }
@@ -176,27 +177,54 @@ static void tcp_ao_key_free_rcu(struct rcu_head *head)
 	kfree_sensitive(key);
 }
 
-void tcp_ao_destroy_sock(struct sock *sk)
+void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
 {
 	struct tcp_ao_info *ao;
 	struct tcp_ao_key *key;
 	struct hlist_node *n;
 
-	ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1);
-	tcp_sk(sk)->ao_info = NULL;
+	if (twsk) {
+		ao = rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1);
+		tcp_twsk(sk)->ao_info = NULL;
+	} else {
+		ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1);
+		tcp_sk(sk)->ao_info = NULL;
+	}
 
-	if (!ao)
+	if (!ao || !refcount_dec_and_test(&ao->refcnt))
 		return;
 
 	hlist_for_each_entry_safe(key, n, &ao->head, node) {
 		hlist_del_rcu(&key->node);
-		atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+		if (!twsk)
+			atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
 		call_rcu(&key->rcu, tcp_ao_key_free_rcu);
 	}
 
 	kfree_rcu(ao, rcu);
 }
 
+void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp)
+{
+	struct tcp_ao_info *ao_info = rcu_dereference_protected(tp->ao_info, 1);
+
+	if (ao_info) {
+		struct tcp_ao_key *key;
+		struct hlist_node *n;
+		int omem = 0;
+
+		hlist_for_each_entry_safe(key, n, &ao_info->head, node) {
+			omem += tcp_ao_sizeof_key(key);
+		}
+
+		refcount_inc(&ao_info->refcnt);
+		atomic_sub(omem, &(((struct sock *)tp)->sk_omem_alloc));
+		rcu_assign_pointer(tcptw->ao_info, ao_info);
+	} else {
+		tcptw->ao_info = NULL;
+	}
+}
+
 /* 4 tuple and ISNs are expected in NBO */
 static int tcp_v4_ao_calc_key(struct tcp_ao_key *mkt, u8 *key,
 			      __be32 saddr, __be32 daddr,
@@ -514,11 +542,13 @@ int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
 	if (!sk)
 		return -ENOTCONN;
 
-	if ((1 << sk->sk_state) &
-	    (TCPF_LISTEN | TCPF_NEW_SYN_RECV | TCPF_TIME_WAIT))
+	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) {
 		return -1;
 
-	ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
+	if (sk->sk_state == TCP_TIME_WAIT)
+		ao_info = rcu_dereference(tcp_twsk(sk)->ao_info);
+	else
+		ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
 	if (!ao_info)
 		return -ENOENT;
 
@@ -910,6 +940,9 @@ static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk)
 	if (sk_fullsock(sk)) {
 		return rcu_dereference_protected(tcp_sk(sk)->ao_info,
 						 lockdep_sock_is_held(sk));
+	} else if (sk->sk_state == TCP_TIME_WAIT) {
+		return rcu_dereference_protected(tcp_twsk(sk)->ao_info,
+						 lockdep_sock_is_held(sk));
 	}
 	return ERR_PTR(-ESOCKTNOSUPPORT);
 }