fwd, pif: Remove duplicated logic between tcp_listen() and udp_listen()

tcp_listen() and udp_listen() have only some simple logic around a call to
pif_listen(), and it's basically identical in each case.  If we move the
common logic into pif_listen() we can then remove {tcp,udp}_listen()
entirely, with their caller in fwd_sync_one() calling pif_listen()
directly.

We also move the logic converting from a protocol id to an epoll type from
fwd_sync_one() into pif_listen().  It's a bit arbitrary, but seems slightly
nicer that way.

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

7 files changed, 27 insertions, 90 deletions

diff --git a/fwd.c b/fwd.c
index c0a6ada..042158c 100644
--- a/fwd.c
+++ b/fwd.c
@@ -389,13 +389,7 @@ static int fwd_sync_one(const struct ctx *c, uint8_t pif, unsigned idx,
 			continue;
 		}
 
-		if (rule->proto == IPPROTO_TCP)
-			fd = tcp_listen(c, pif, idx, addr, ifname, port);
-		else if (rule->proto == IPPROTO_UDP)
-			fd = udp_listen(c, pif, idx, addr, ifname, port);
-		else
-			assert(0);
-
+		fd = pif_listen(c, rule->proto, pif, addr, ifname, port, idx);
 		if (fd < 0) {
 			char astr[INANY_ADDRSTRLEN];
 
diff --git a/pif.c b/pif.c
index d5e3161..4cf0f6e 100644
--- a/pif.c
+++ b/pif.c
@@ -64,7 +64,7 @@ void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa,
 
 /** pif_listen() - Open a listening socket on a specified pif
  * @c:		Execution context
- * @type:	Socket epoll type
+ * @proto:	Socket protocol (IPPROTO_TCP or IPPROTO_UDP)
  * @pif:	Interface for this socket
  * @addr:	Address to bind to, or NULL for dual-stack any
  * @ifname:	Interface for binding, NULL for any
@@ -76,15 +76,38 @@ void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa,
  *
  * Return: newly created socket, negative error code on failure
  */
-int pif_listen(const struct ctx *c, enum epoll_type type, uint8_t pif,
+int pif_listen(const struct ctx *c, uint8_t proto, uint8_t pif,
 	       const union inany_addr *addr, const char *ifname,
 	       in_port_t port, unsigned rule)
 {
+	enum epoll_type type;
 	union epoll_ref ref;
 	int ret;
 
 	assert(pif_is_socket(pif));
 
+	if (proto == IPPROTO_TCP)
+		type = EPOLL_TYPE_TCP_LISTEN;
+	else if (proto == IPPROTO_UDP)
+		type = EPOLL_TYPE_UDP_LISTEN;
+	else
+		return -EPROTONOSUPPORT;
+
+	if (!c->ifi4) {
+		if (!addr)
+			/* Restrict to v6 only */
+			addr = &inany_any6;
+		else if (inany_v4(addr))
+			return -EAFNOSUPPORT;
+	}
+	if (!c->ifi6) {
+		if (!addr)
+			/* Restrict to v4 only */
+			addr = &inany_any4;
+		else if (!inany_v4(addr))
+			return -EAFNOSUPPORT;
+	}
+
 	if (!addr) {
 		ref.fd = sock_l4_dualstack_any(c, type, port, ifname);
 	} else {
diff --git a/pif.h b/pif.h
index 62223d1..3a1e2e5 100644
--- a/pif.h
+++ b/pif.h
@@ -66,7 +66,7 @@ static inline bool pif_is_socket(uint8_t pif)
 
 void pif_sockaddr(const struct ctx *c, union sockaddr_inany *sa,
 		  uint8_t pif, const union inany_addr *addr, in_port_t port);
-int pif_listen(const struct ctx *c, enum epoll_type type, uint8_t pif,
+int pif_listen(const struct ctx *c, uint8_t proto, uint8_t pif,
 	       const union inany_addr *addr, const char *ifname,
 	       in_port_t port, unsigned rule);
 
diff --git a/tcp.c b/tcp.c
index 10d9d0d..097ab72 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2761,44 +2761,6 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
 }
 
 /**
- * tcp_listen() - Create listening socket
- * @c:		Execution context
- * @pif:	Interface to open the socket for (PIF_HOST or PIF_SPLICE)
- * @rule:	Index of relevant forwarding rule
- * @addr:	Pointer to address for binding, NULL for any
- * @ifname:	Name of interface to bind to, NULL for any
- * @port:	Port, host order
- *
- * Return: socket fd on success, negative error code on failure
- */
-int tcp_listen(const struct ctx *c, uint8_t pif, unsigned rule,
-	       const union inany_addr *addr, const char *ifname, in_port_t port)
-{
-	int s;
-
-	assert(!c->no_tcp);
-
-	if (!c->ifi4) {
-		if (!addr)
-			/* Restrict to v6 only */
-			addr = &inany_any6;
-		else if (inany_v4(addr))
-			return -EAFNOSUPPORT;
-	}
-	if (!c->ifi6) {
-		if (!addr)
-			/* Restrict to v4 only */
-			addr = &inany_any4;
-		else if (!inany_v4(addr))
-			return -EAFNOSUPPORT;
-	}
-
-	s = pif_listen(c, EPOLL_TYPE_TCP_LISTEN, pif, addr, ifname, port, rule);
-
-	return s;
-}
-
-/**
  * tcp_sock_refill_pool() - Refill one pool of pre-opened sockets
  * @pool:	Pool of sockets to refill
  * @af:		Address family to use
diff --git a/tcp.h b/tcp.h
index 3262a80..57deef5 100644
--- a/tcp.h
+++ b/tcp.h
@@ -26,8 +26,6 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
 int tcp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 		    const void *saddr, const void *daddr, uint32_t flow_lbl,
 		    const struct pool *p, int idx, const struct timespec *now);
-int tcp_listen(const struct ctx *c, uint8_t pif, unsigned rule,
-	       const union inany_addr *addr, const char *ifname, in_port_t port);
 int tcp_init(struct ctx *c);
 void tcp_defer_handler(struct ctx *c, const struct timespec *now);
 
diff --git a/udp.c b/udp.c
index c28d6ee..375befa 100644
--- a/udp.c
+++ b/udp.c
@@ -1125,44 +1125,6 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 }
 
 /**
- * udp_listen() - Initialise listening socket for a given port
- * @c:		Execution context
- * @pif:	Interface to open the socket for (PIF_HOST or PIF_SPLICE)
- * @rule:	Index of relevant forwarding rule
- * @addr:	Pointer to address for binding, NULL if not configured
- * @ifname:	Name of interface to bind to, NULL if not configured
- * @port:	Port, host order
- *
- * Return: socket fd on success, negative error code on failure
- */
-int udp_listen(const struct ctx *c, uint8_t pif, unsigned rule,
-	       const union inany_addr *addr, const char *ifname, in_port_t port)
-{
-	int s;
-
-	assert(!c->no_udp);
-
-	if (!c->ifi4) {
-		if (!addr)
-			/* Restrict to v6 only */
-			addr = &inany_any6;
-		else if (inany_v4(addr))
-			return -EAFNOSUPPORT;
-	}
-	if (!c->ifi6) {
-		if (!addr)
-			/* Restrict to v4 only */
-			addr = &inany_any4;
-		else if (!inany_v4(addr))
-			return -EAFNOSUPPORT;
-	}
-
-	s = pif_listen(c, EPOLL_TYPE_UDP_LISTEN, pif, addr, ifname, port, rule);
-
-	return s;
-}
-
-/**
  * udp_splice_iov_init() - Set up buffers and descriptors for recvmmsg/sendmmsg
  */
 static void udp_splice_iov_init(void)
diff --git a/udp.h b/udp.h
index a75d5ae..9ea7de6 100644
--- a/udp.h
+++ b/udp.h
@@ -19,8 +19,6 @@ int udp_tap_handler(const struct ctx *c, uint8_t pif,
 		    sa_family_t af, const void *saddr, const void *daddr,
 		    uint8_t ttl, const struct pool *p, int idx,
 		    const struct timespec *now);
-int udp_listen(const struct ctx *c, uint8_t pif, unsigned rule,
-	       const union inany_addr *addr, const char *ifname, in_port_t port);
 int udp_init(struct ctx *c);
 void udp_update_l2_buf(const unsigned char *eth_d);