[MINOR] add socket address length to the protocols

The protocol struct can be more useful if it also provides
address lengths. Add sock_addrlen, as used by bind(), as
well as l3_addrlen for hashes.

include/types/protocols.h

@@ -78,6 +78,8 @@ struct protocol {
 	int sock_type;					/* socket type, as passed to socket()     */
 	int sock_prot;					/* socket protocol, as passed to socket() */
 	sa_family_t sock_family;			/* socket family, for sockaddr */
+	socklen_t sock_addrlen;				/* socket address length, used by bind() */
+	int l3_addrlen;					/* layer3 address length, used by hashes */
 	int (*read)(int fd);				/* generic read function */
 	int (*write)(int fd);				/* generic write function */
 	int (*bind_all)(struct protocol *proto);	/* bind all unbound listeners */

src/proto_uxst.c

@@ -1407,6 +1407,8 @@ static struct protocol proto_unix = {
 	.sock_type = SOCK_STREAM,
 	.sock_prot = 0,
 	.sock_family = AF_UNIX,
+	.sock_addrlen = sizeof(struct sockaddr_un),
+	.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),/* path len */
 	.read = &stream_sock_read,
 	.write = &stream_sock_write,
 	.bind_all = uxst_bind_listeners,