[SCTP]: enable v6 autobinding.

This is just more address cleanup really, but the sideeffect is that 
this enables the autobinding on PF_INET6 sockets. 

include/net/sctp/structs.h

@@ -259,6 +259,7 @@ typedef struct sctp_func {
 					 int saddr);
 	int             (*addr_valid)   (union sctp_addr *);
 	sctp_scope_t    (*scope) (union sctp_addr *);
+	void            (*inaddr_any)   (union sctp_addr *, unsigned short);
 	__u16		net_header_len;
 	int		sockaddr_len;
 	sa_family_t	sa_family;
@@ -272,6 +273,7 @@ typedef struct sctp_pf {
 	void (*event_msgname)(sctp_ulpevent_t *, char *, int *);
 	void (*skb_msgname)(struct sk_buff *, char *, int *);
 	int  (*af_supported)(sa_family_t);
+	struct sctp_func *af;
 } sctp_pf_t;
 
 /* SCTP Socket type: UDP or TCP style. */

net/sctp/ipv6.c

@@ -269,6 +269,14 @@ static int sctp_v6_cmp_saddr(struct dst_entry *dst, union sctp_addr *saddr)
 	return ipv6_addr_cmp(&rt->rt6i_src.addr, &saddr->v6.sin6_addr);
 }
 
+/* Initialize addr struct to INADDR_ANY. */
+void sctp_v6_inaddr_any(union sctp_addr *addr, unsigned short port)
+{
+	memset(addr, 0x00, sizeof(union sctp_addr));
+	addr->v6.sin6_family = AF_INET6;
+	addr->v6.sin6_port = port;
+}
+
 /* This function checks if the address is a valid address to be used for
  * SCTP.
  *
@@ -454,6 +462,7 @@ static sctp_func_t sctp_ipv6_specific = {
 	.cmp_saddr	 = sctp_v6_cmp_saddr,
 	.scope           = sctp_v6_scope,
 	.addr_valid      = sctp_v6_addr_valid,
+	.inaddr_any      = sctp_v6_inaddr_any,
 	.net_header_len  = sizeof(struct ipv6hdr),
 	.sockaddr_len    = sizeof(struct sockaddr_in6),
 	.sa_family       = AF_INET6,
@@ -463,6 +472,7 @@ static sctp_pf_t sctp_pf_inet6_specific = {
 	.event_msgname = sctp_inet6_event_msgname,
 	.skb_msgname   = sctp_inet6_skb_msgname,
 	.af_supported  = sctp_inet6_af_supported,
+	.af            = &sctp_ipv6_specific,
 };
 
 /* Initialize IPv6 support and register with inet6 stack.  */

net/sctp/protocol.c

@@ -283,6 +283,14 @@ int sctp_v4_cmp_saddr(struct dst_entry *dst, union sctp_addr *saddr)
 	return (rt->rt_src == saddr->v4.sin_addr.s_addr);
 }
 
+/* Initialize addr struct to INADDR_ANY. */
+void sctp_v4_inaddr_any(union sctp_addr *addr, unsigned short port)
+{
+	addr->v4.sin_family = AF_INET;
+	addr->v4.sin_addr.s_addr = INADDR_ANY;
+	addr->v4.sin_port = port;
+}
+
 /* This function checks if the address is a valid address to be used for
  * SCTP.
  *
@@ -440,10 +448,13 @@ static int sctp_inet_af_supported(sa_family_t family)
 	return (AF_INET == family);
 }
 
+struct sctp_func sctp_ipv4_specific;
+
 static sctp_pf_t sctp_pf_inet = {
 	.event_msgname = sctp_inet_event_msgname,
 	.skb_msgname   = sctp_inet_skb_msgname,
 	.af_supported  = sctp_inet_af_supported,
+	.af            = &sctp_ipv4_specific,
 };
 
 
@@ -500,6 +511,7 @@ struct sctp_func sctp_ipv4_specific = {
 	.from_skb       = sctp_v4_from_skb,
 	.cmp_saddr	= sctp_v4_cmp_saddr,
 	.addr_valid     = sctp_v4_addr_valid,
+	.inaddr_any     = sctp_v4_inaddr_any,
 	.scope          = sctp_v4_scope,
 	.net_header_len = sizeof(struct iphdr),
 	.sockaddr_len   = sizeof(struct sockaddr_in),

net/sctp/socket.c

@@ -2377,33 +2377,16 @@ void sctp_put_port(struct sock *sk)
 static int sctp_autobind(struct sock *sk)
 {
 	union sctp_addr autoaddr;
-	int addr_len = 0;
-
-	memset(&autoaddr, 0, sizeof(union sctp_addr));
+	struct sctp_func *af;
+	unsigned short port;
 
-	switch (sk->family) {
-	case PF_INET:
-		autoaddr.v4.sin_family = AF_INET;
-		autoaddr.v4.sin_addr.s_addr = INADDR_ANY;
-		autoaddr.v4.sin_port = htons(inet_sk(sk)->num);
-		addr_len = sizeof(struct sockaddr_in);
-		break;
+	/* Initialize a local sockaddr structure to INADDR_ANY. */
+	af = sctp_sk(sk)->pf->af;
 
-	case PF_INET6:
-		SCTP_V6(
-			/* FIXME: Write me for v6!  */
-			BUG();
-			autoaddr.v6.sin6_family = AF_INET6;
-			autoaddr.v6.sin6_port = htons(inet_sk(sk)->num);
-			addr_len = sizeof(struct sockaddr_in6);
-		);
-		break;
-
-	default: /* This should not happen.  */
-		break;
-	};
+	port = htons(inet_sk(sk)->num);
+	af->inaddr_any(&autoaddr, port);
 
-	return sctp_do_bind(sk, &autoaddr, addr_len);
+	return sctp_do_bind(sk, &autoaddr, af->sockaddr_len);
 }
 
 /* Parse out IPPROTO_SCTP CMSG headers.  Perform only minimal validation.