[DCCP] ipv6: Add missing ipv6 control socket

I guess I forgot to add it, nah, now it just works:

18:04:33.274066 IP6 ::1.1476 > ::1.5001: request (service=0)
18:04:33.334482 IP6 ::1.5001 > ::1.1476: reset (code=bad_service_code)

Ditched IP_DCCP_UNLOAD_HACK, as now we would have to do it for both
IPv6 and IPv4, so I'll come up with another way for freeing the
control sockets in upcoming changesets.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/Kconfig

@@ -40,15 +40,6 @@ config IP_DCCP_DEBUG
 
 	  Just say N.
 
-config IP_DCCP_UNLOAD_HACK
-	depends on IP_DCCP=m && IP_DCCP_CCID3=m
-	bool "DCCP control sock unload hack"
-	---help---
-	  Enable this to be able to unload the dccp module when the it
-	  has only one refcount held, the control sock one. Just execute
-	  "rmmod dccp_ccid3 dccp"
-
-	  Just say N.
 endmenu
 
 endmenu

net/dccp/ccids/ccid3.c

@@ -1211,15 +1211,6 @@ module_init(ccid3_module_init);
 
 static __exit void ccid3_module_exit(void)
 {
-#ifdef CONFIG_IP_DCCP_UNLOAD_HACK
-	/*
-	 * Hack to use while developing, so that we get rid of the control
-	 * sock, that is what keeps a refcount on dccp.ko -acme
-	 */
-	extern void dccp_ctl_sock_exit(void);
-
-	dccp_ctl_sock_exit();
-#endif
 	ccid_unregister(&ccid3);
 
 	if (ccid3_tx_hist != NULL) {

net/dccp/dccp.h

@@ -177,7 +177,7 @@ extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 				const struct dccp_hdr *dh, const unsigned len);
 
-extern int dccp_init_sock(struct sock *sk);
+extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
 extern int dccp_destroy_sock(struct sock *sk);
 
 extern void		dccp_close(struct sock *sk, long timeout);
@@ -337,8 +337,6 @@ extern void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 			       unsigned char option,
 			       const void *value, unsigned char len);
 
-extern struct socket *dccp_ctl_socket;
-
 extern void dccp_timestamp(const struct sock *sk, struct timeval *tv);
 
 static inline suseconds_t timeval_usecs(const struct timeval *tv)

net/dccp/ipv4.c

@@ -32,6 +32,13 @@
 #include "dccp.h"
 #include "feat.h"
 
+/*
+ * This is the global socket data structure used for responding to
+ * the Out-of-the-blue (OOTB) packets. A control sock will be created
+ * for this socket at the initialization time.
+ */
+static struct socket *dccp_v4_ctl_socket;
+
 static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
 {
 	return inet_csk_get_port(&dccp_hashinfo, sk, snum,
@@ -226,11 +233,11 @@ static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
 	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
 			 DCCP_SKB_CB(rxskb)->dccpd_seq);
 
-	bh_lock_sock(dccp_ctl_socket->sk);
-	err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
+	bh_lock_sock(dccp_v4_ctl_socket->sk);
+	err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
 				    rxskb->nh.iph->daddr,
 				    rxskb->nh.iph->saddr, NULL);
-	bh_unlock_sock(dccp_ctl_socket->sk);
+	bh_unlock_sock(dccp_v4_ctl_socket->sk);
 
 	if (err == NET_XMIT_CN || err == 0) {
 		DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
@@ -704,7 +711,7 @@ static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
 	if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
 		return;
 
-	dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
+	dst = dccp_v4_route_skb(dccp_v4_ctl_socket->sk, rxskb);
 	if (dst == NULL)
 		return;
 
@@ -741,11 +748,11 @@ static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
 	dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
 					      rxskb->nh.iph->daddr);
 
-	bh_lock_sock(dccp_ctl_socket->sk);
-	err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
+	bh_lock_sock(dccp_v4_ctl_socket->sk);
+	err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
 				    rxskb->nh.iph->daddr,
 				    rxskb->nh.iph->saddr, NULL);
-	bh_unlock_sock(dccp_ctl_socket->sk);
+	bh_unlock_sock(dccp_v4_ctl_socket->sk);
 
 	if (err == NET_XMIT_CN || err == 0) {
 		DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
@@ -997,10 +1004,15 @@ static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
 
 static int dccp_v4_init_sock(struct sock *sk)
 {
-	const int err = dccp_init_sock(sk);
+	static __u8 dccp_v4_ctl_sock_initialized;
+	int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
 
-	if (err == 0)
+	if (err == 0) {
+		if (unlikely(!dccp_v4_ctl_sock_initialized))
+			dccp_v4_ctl_sock_initialized = 1;
 		inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
+	}
+
 	return err;
 }
 
@@ -1087,48 +1099,29 @@ static struct inet_protosw dccp_v4_protosw = {
 	.flags		= INET_PROTOSW_ICSK,
 };
 
-/*
- * This is the global socket data structure used for responding to
- * the Out-of-the-blue (OOTB) packets. A control sock will be created
- * for this socket at the initialization time.
- */
-struct socket *dccp_ctl_socket;
-
-static char dccp_ctl_socket_err_msg[] __initdata =
+static char dccp_v4_ctl_socket_err_msg[] __initdata =
 	KERN_ERR "DCCP: Failed to create the control socket.\n";
 
-static int __init dccp_ctl_sock_init(void)
+static int __init dccp_v4_ctl_sock_init(void)
 {
 	int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
-				  &dccp_ctl_socket);
+				  &dccp_v4_ctl_socket);
 	if (rc < 0)
-		printk(dccp_ctl_socket_err_msg);
+		printk(dccp_v4_ctl_socket_err_msg);
 	else {
-		dccp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
-		inet_sk(dccp_ctl_socket->sk)->uc_ttl = -1;
+		dccp_v4_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
+		inet_sk(dccp_v4_ctl_socket->sk)->uc_ttl = -1;
 
 		/* Unhash it so that IP input processing does not even
 		 * see it, we do not wish this socket to see incoming
 		 * packets.
 		 */
-		dccp_ctl_socket->sk->sk_prot->unhash(dccp_ctl_socket->sk);
+		dccp_v4_ctl_socket->sk->sk_prot->unhash(dccp_v4_ctl_socket->sk);
 	}
 
 	return rc;
 }
 
-#ifdef CONFIG_IP_DCCP_UNLOAD_HACK
-void dccp_ctl_sock_exit(void)
-{
-	if (dccp_ctl_socket != NULL) {
-		sock_release(dccp_ctl_socket);
-		dccp_ctl_socket = NULL;
-	}
-}
-
-EXPORT_SYMBOL_GPL(dccp_ctl_sock_exit);
-#endif
-
 static int __init dccp_v4_init(void)
 {
 	int err = proto_register(&dccp_v4_prot, 1);
@@ -1142,7 +1135,7 @@ static int __init dccp_v4_init(void)
 
 	inet_register_protosw(&dccp_v4_protosw);
 
-	err = dccp_ctl_sock_init();
+	err = dccp_v4_ctl_sock_init();
 	if (err)
 		goto out_unregister_protosw;
 out:

net/dccp/ipv6.c

@@ -33,6 +33,9 @@
 #include "dccp.h"
 #include "ipv6.h"
 
+/* Socket used for sending RSTs and ACKs */
+static struct socket *dccp_v6_ctl_socket;
+
 static void dccp_v6_ctl_send_reset(struct sk_buff *skb);
 static void dccp_v6_reqsk_send_ack(struct sk_buff *skb,
 				   struct request_sock *req);
@@ -568,7 +571,7 @@ static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
 	/* sk = NULL, but it is safe for now. RST socket required. */
 	if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
 		if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
-			ip6_xmit(NULL, skb, &fl, NULL, 0);
+			ip6_xmit(dccp_v6_ctl_socket->sk, skb, &fl, NULL, 0);
 			DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
 			DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
 			return;
@@ -623,7 +626,7 @@ static void dccp_v6_ctl_send_ack(struct sk_buff *rxskb)
 
 	if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
 		if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
-			ip6_xmit(NULL, skb, &fl, NULL, 0);
+			ip6_xmit(dccp_v6_ctl_socket->sk, skb, &fl, NULL, 0);
 			DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
 			return;
 		}
@@ -1146,10 +1149,14 @@ static struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
  */
 static int dccp_v6_init_sock(struct sock *sk)
 {
-	int err = dccp_init_sock(sk);
+	static __u8 dccp_v6_ctl_sock_initialized;
+	int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
 
-	if (err == 0)
+	if (err == 0) {
+		if (unlikely(!dccp_v6_ctl_sock_initialized))
+			dccp_v6_ctl_sock_initialized = 1;
 		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
+	}
 
 	return err;
 }
@@ -1222,6 +1229,29 @@ static struct inet_protosw dccp_v6_protosw = {
 	.flags		= INET_PROTOSW_ICSK,
 };
 
+static char dccp_v6_ctl_socket_err_msg[] __initdata =
+	KERN_ERR "DCCP: Failed to create the control socket.\n";
+
+static int __init dccp_v6_ctl_sock_init(void)
+{
+	int rc = sock_create_kern(PF_INET6, SOCK_DCCP, IPPROTO_DCCP,
+				  &dccp_v6_ctl_socket);
+	if (rc < 0)
+		printk(dccp_v6_ctl_socket_err_msg);
+	else {
+		dccp_v6_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
+		inet_sk(dccp_v6_ctl_socket->sk)->uc_ttl = -1;
+
+		/* Unhash it so that IP input processing does not even
+		 * see it, we do not wish this socket to see incoming
+		 * packets.
+		 */
+		dccp_v6_ctl_socket->sk->sk_prot->unhash(dccp_v6_ctl_socket->sk);
+	}
+
+	return rc;
+}
+
 static int __init dccp_v6_init(void)
 {
 	int err = proto_register(&dccp_v6_prot, 1);
@@ -1234,8 +1264,14 @@ static int __init dccp_v6_init(void)
 		goto out_unregister_proto;
 
 	inet6_register_protosw(&dccp_v6_protosw);
+
+	if (dccp_v6_ctl_sock_init() != 0)
+		goto out_unregister_protosw;
 out:
 	return err;
+out_unregister_protosw:
+	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	inet6_unregister_protosw(&dccp_v6_protosw);
 out_unregister_proto:
 	proto_unregister(&dccp_v6_prot);
 	goto out;

net/dccp/proto.c

@@ -163,11 +163,10 @@ void dccp_unhash(struct sock *sk)
 
 EXPORT_SYMBOL_GPL(dccp_unhash);
 
-int dccp_init_sock(struct sock *sk)
+int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
-	static int dccp_ctl_socket_init = 1;
 
 	dccp_options_init(&dp->dccps_options);
 	do_gettimeofday(&dp->dccps_epoch);
@@ -179,7 +178,7 @@ int dccp_init_sock(struct sock *sk)
 	 * lets leave it here, later the real solution is to do this in a
 	 * setsockopt(CCIDs-I-want/accept). -acme
 	 */
-	if (likely(!dccp_ctl_socket_init)) {
+	if (likely(ctl_sock_initialized)) {
 		int rc = dccp_feat_init(sk);
 
 		if (rc)
@@ -211,7 +210,6 @@ int dccp_init_sock(struct sock *sk)
 		/* control socket doesn't need feat nego */
 		INIT_LIST_HEAD(&dp->dccps_options.dccpo_pending);
 		INIT_LIST_HEAD(&dp->dccps_options.dccpo_conf);
-		dccp_ctl_socket_init = 0;
 	}
 
 	dccp_init_xmit_timers(sk);