[IPV6]: Fix infinite loop in udp_v6_get_port().

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/udp.c

@@ -99,7 +99,7 @@ static int udp_v6_get_port(struct sock *sk, unsigned short snum)
 		next:;
 		}
 		result = best;
-		for(;; result += UDP_HTABLE_SIZE) {
+		for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) {
 			if (result > sysctl_local_port_range[1])
 				result = sysctl_local_port_range[0]
 					+ ((result - sysctl_local_port_range[0]) &
@@ -107,6 +107,8 @@ static int udp_v6_get_port(struct sock *sk, unsigned short snum)
 			if (!udp_lport_inuse(result))
 				break;
 		}
+		if (i >= (1 << 16) / UDP_HTABLE_SIZE)
+			goto fail;
 gotit:
 		udp_port_rover = snum = result;
 	} else {