SCTP: Fix SCTP_SET_PEER_PRIMARY_ADDR to accpet v4mapped address

SCTP_SET_PEER_PRIMARY_ADDR does not accpet v4mapped address, using
v4mapped address in SCTP_SET_PEER_PRIMARY_ADDR socket option will
get -EADDRNOTAVAIL error if v4map is enabled. This patch try to
fix it by mapping v4mapped address to v4 address if allowed.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -2932,6 +2932,7 @@ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optva
 	struct sctp_association	*asoc = NULL;
 	struct sctp_setpeerprim	prim;
 	struct sctp_chunk	*chunk;
+	struct sctp_af		*af;
 	int 			err;
 
 	sp = sctp_sk(sk);
@@ -2959,6 +2960,13 @@ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optva
 	if (!sctp_state(asoc, ESTABLISHED))
 		return -ENOTCONN;
 
+	af = sctp_get_af_specific(prim.sspp_addr.ss_family);
+	if (!af)
+		return -EINVAL;
+
+	if (!af->addr_valid((union sctp_addr *)&prim.sspp_addr, sp, NULL))
+		return -EADDRNOTAVAIL;
+
 	if (!sctp_assoc_lookup_laddr(asoc, (union sctp_addr *)&prim.sspp_addr))
 		return -EADDRNOTAVAIL;