dccp: Call inet6_destroy_sock() via sk->sk_destruct().

After commit d38afeec ("tcp/udp: Call inet6_destroy_sock()
in IPv6 sk->sk_destruct()."), we call inet6_destroy_sock() in
sk->sk_destruct() by setting inet6_sock_destruct() to it to make
sure we do not leak inet6-specific resources.

DCCP sets its own sk->sk_destruct() in the dccp_init_sock(), and
DCCPv6 socket shares it by calling the same init function via
dccp_v6_init_sock().

To call inet6_sock_destruct() from DCCPv6 sk->sk_destruct(), we
export it and set dccp_v6_sk_destruct() in the init function.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/dccp.h

@@ -278,6 +278,7 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 			 const struct dccp_hdr *dh, const unsigned int len);
 
+void dccp_destruct_common(struct sock *sk);
 int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
 void dccp_destroy_sock(struct sock *sk);
 

net/dccp/ipv6.c

@@ -1021,6 +1021,12 @@ static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
 	.sockaddr_len	   = sizeof(struct sockaddr_in6),
 };
 
+static void dccp_v6_sk_destruct(struct sock *sk)
+{
+	dccp_destruct_common(sk);
+	inet6_sock_destruct(sk);
+}
+
 /* NOTE: A lot of things set to zero explicitly by call to
  *       sk_alloc() so need not be done here.
  */
@@ -1033,17 +1039,12 @@ static int dccp_v6_init_sock(struct sock *sk)
 		if (unlikely(!dccp_v6_ctl_sock_initialized))
 			dccp_v6_ctl_sock_initialized = 1;
 		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
+		sk->sk_destruct = dccp_v6_sk_destruct;
 	}
 
 	return err;
 }
 
-static void dccp_v6_destroy_sock(struct sock *sk)
-{
-	dccp_destroy_sock(sk);
-	inet6_destroy_sock(sk);
-}
-
 static struct timewait_sock_ops dccp6_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct dccp6_timewait_sock),
 };
@@ -1066,7 +1067,7 @@ static struct proto dccp_v6_prot = {
 	.accept		   = inet_csk_accept,
 	.get_port	   = inet_csk_get_port,
 	.shutdown	   = dccp_shutdown,
-	.destroy	   = dccp_v6_destroy_sock,
+	.destroy	   = dccp_destroy_sock,
 	.orphan_count	   = &dccp_orphan_count,
 	.max_header	   = MAX_DCCP_HEADER,
 	.obj_size	   = sizeof(struct dccp6_sock),

net/dccp/proto.c

@@ -171,12 +171,18 @@ const char *dccp_packet_name(const int type)
 
 EXPORT_SYMBOL_GPL(dccp_packet_name);
 
-static void dccp_sk_destruct(struct sock *sk)
+void dccp_destruct_common(struct sock *sk)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 
 	ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 	dp->dccps_hc_tx_ccid = NULL;
+}
+EXPORT_SYMBOL_GPL(dccp_destruct_common);
+
+static void dccp_sk_destruct(struct sock *sk)
+{
+	dccp_destruct_common(sk);
 	inet_sock_destruct(sk);
 }
 

net/ipv6/af_inet6.c

@@ -114,6 +114,7 @@ void inet6_sock_destruct(struct sock *sk)
 	inet6_cleanup_sock(sk);
 	inet_sock_destruct(sk);
 }
+EXPORT_SYMBOL_GPL(inet6_sock_destruct);
 
 static int inet6_create(struct net *net, struct socket *sock, int protocol,
 			int kern)