util: sock_l4() determine protocol from epoll type rather than the reverse

sock_l4() creates a socket of the given IP protocol number, and adds it to
the epoll state.  Currently it determines the correct tag for the epoll
data based on the protocol.  However, we have some future cases where we
might want different semantics, and therefore epoll types, for sockets of
the same protocol.  So, change sock_l4() to take the epoll type as an
explicit parameter, and determine the protocol from that.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 26 insertions, 22 deletions

diff --git a/util.c b/util.c
index dd2e57f..9a73fbb 100644
--- a/util.c
+++ b/util.c
@@ -35,7 +35,7 @@
 /**
  * sock_l4_sa() - Create and bind socket to socket address, add to epoll list
  * @c:		Execution context
- * @proto:	Protocol number
+ * @type:	epoll type
  * @sa:		Socket address to bind to
  * @sl:		Length of @sa
  * @ifname:	Interface for binding, NULL for any
@@ -44,34 +44,38 @@
  *
  * Return: newly created socket, negative error code on failure
  */
-static int sock_l4_sa(const struct ctx *c, uint8_t proto,
+static int sock_l4_sa(const struct ctx *c, enum epoll_type type,
 		      const void *sa, socklen_t sl,
 		      const char *ifname, bool v6only, uint32_t data)
 {
 	sa_family_t af = ((const struct sockaddr *)sa)->sa_family;
-	union epoll_ref ref = { .data = data };
+	union epoll_ref ref = { .type = type, .data = data };
 	struct epoll_event ev;
 	int fd, y = 1, ret;
+	uint8_t proto;
+	int socktype;
 
-	switch (proto) {
-	case IPPROTO_TCP:
-		ref.type = EPOLL_TYPE_TCP_LISTEN;
+	switch (type) {
+	case EPOLL_TYPE_TCP_LISTEN:
+		proto = IPPROTO_TCP;
+		socktype = SOCK_STREAM | SOCK_NONBLOCK;
 		break;
-	case IPPROTO_UDP:
-		ref.type = EPOLL_TYPE_UDP;
+	case EPOLL_TYPE_UDP:
+		proto = IPPROTO_UDP;
+		socktype = SOCK_DGRAM | SOCK_NONBLOCK;
 		break;
-	case IPPROTO_ICMP:
-	case IPPROTO_ICMPV6:
-		ref.type = EPOLL_TYPE_PING;
+	case EPOLL_TYPE_PING:
+		if (af == AF_INET)
+			proto = IPPROTO_ICMP;
+		else
+			proto = IPPROTO_ICMPV6;
+		socktype = SOCK_DGRAM | SOCK_NONBLOCK;
 		break;
 	default:
-		return -EPFNOSUPPORT;	/* Not implemented. */
+		ASSERT(0);
 	}
 
-	if (proto == IPPROTO_TCP)
-		fd = socket(af, SOCK_STREAM | SOCK_NONBLOCK, proto);
-	else
-		fd = socket(af, SOCK_DGRAM | SOCK_NONBLOCK, proto);
+	fd = socket(af, socktype, proto);
 
 	ret = -errno;
 	if (fd < 0) {
@@ -118,14 +122,14 @@ static int sock_l4_sa(const struct ctx *c, uint8_t proto,
 		 * this is fine. This might also fail for ICMP because of a
 		 * broken SELinux policy, see icmp_tap_handler().
 		 */
-		if (proto != IPPROTO_ICMP && proto != IPPROTO_ICMPV6) {
+		if (type != EPOLL_TYPE_PING) {
 			ret = -errno;
 			close(fd);
 			return ret;
 		}
 	}
 
-	if (proto == IPPROTO_TCP && listen(fd, 128) < 0) {
+	if (type == EPOLL_TYPE_TCP_LISTEN && listen(fd, 128) < 0) {
 		ret = -errno;
 		warn("TCP socket listen: %s", strerror(-ret));
 		close(fd);
@@ -146,7 +150,7 @@ static int sock_l4_sa(const struct ctx *c, uint8_t proto,
  * sock_l4() - Create and bind socket for given L4, add to epoll list
  * @c:		Execution context
  * @af:		Address family, AF_INET or AF_INET6
- * @proto:	Protocol number
+ * @type:	epoll type
  * @bind_addr:	Address for binding, NULL for any
  * @ifname:	Interface for binding, NULL for any
  * @port:	Port, host order
@@ -154,7 +158,7 @@ static int sock_l4_sa(const struct ctx *c, uint8_t proto,
  *
  * Return: newly created socket, negative error code on failure
  */
-int sock_l4(const struct ctx *c, sa_family_t af, uint8_t proto,
+int sock_l4(const struct ctx *c, sa_family_t af, enum epoll_type type,
 	    const void *bind_addr, const char *ifname, uint16_t port,
 	    uint32_t data)
 {
@@ -167,7 +171,7 @@ int sock_l4(const struct ctx *c, sa_family_t af, uint8_t proto,
 		};
 		if (bind_addr)
 			addr4.sin_addr = *(struct in_addr *)bind_addr;
-		return sock_l4_sa(c, proto, &addr4, sizeof(addr4), ifname,
+		return sock_l4_sa(c, type, &addr4, sizeof(addr4), ifname,
 				  false, data);
 	}
 
@@ -188,7 +192,7 @@ int sock_l4(const struct ctx *c, sa_family_t af, uint8_t proto,
 			    sizeof(c->ip6.addr_ll)))
 				addr6.sin6_scope_id = c->ifi6;
 		}
-		return sock_l4_sa(c, proto, &addr6, sizeof(addr6), ifname,
+		return sock_l4_sa(c, type, &addr6, sizeof(addr6), ifname,
 				  af == AF_INET6, data);
 	}
 	default: