[PATCH 1/3] tcp: Merge tcp_ns_sock_init[46]() into tcp_sock_init_one()

[David Gibson <david@gibson.dropbear.id.au>]

Surprisingly little logic is shared between the path for creating a
listen()ing socket in the guest namespace versus in the host namespace.
Improve this, by extending tcp_sock_init_one() to take a pif parameter
indicating where it should open the socket.  This allows
tcp_ns_sock_init[46]() to be removed entirely.

We generalise tcp_sock_init() in the same way, although we don't use it
yet, due to some subtle differences in how we bind for -t versus -T.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 conf.c |  2 +-
 tcp.c  | 96 ++++++++++++++++++----------------------------------------
 tcp.h  |  5 +--
 3 files changed, 33 insertions(+), 70 deletions(-)

diff --git a/conf.c b/conf.c
index 66b9e634..26f1bcc0 100644
--- a/conf.c
+++ b/conf.c
@@ -169,7 +169,7 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
 		fwd->delta[i] = to - first;
 
 		if (optname == 't')
-			ret = tcp_sock_init(c, addr, ifname, i);
+			ret = tcp_sock_init(c, PIF_HOST, addr, ifname, i);
 		else if (optname == 'u')
 			ret = udp_sock_init(c, 0, addr, ifname, i);
 		else
diff --git a/tcp.c b/tcp.c
index 0f9e9b3f..15c012d7 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2515,29 +2515,38 @@ void tcp_sock_handler(const struct ctx *c, union epoll_ref ref,
 /**
  * tcp_sock_init_one() - Initialise listening socket for address and port
  * @c:		Execution context
+ * @pif:	Interface to open the socket for (PIF_HOST or PIF_SPLICE)
  * @addr:	Pointer to address for binding, NULL for dual stack any
  * @ifname:	Name of interface to bind to, NULL if not configured
  * @port:	Port, host order
  *
  * Return: fd for the new listening socket, negative error code on failure
+ *
+ * If pif == PIF_SPLICE, must have already entered the namespace.
  */
-static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr,
-			     const char *ifname, in_port_t port)
+static int tcp_sock_init_one(const struct ctx *c, uint8_t pif,
+			     const union inany_addr *addr, const char *ifname,
+			     in_port_t port)
 {
+	const struct fwd_ports *fwd = pif == PIF_HOST ?
+		&c->tcp.fwd_in : &c->tcp.fwd_out;
 	union tcp_listen_epoll_ref tref = {
 		.port = port,
-		.pif = PIF_HOST,
+		.pif = pif,
 	};
 	int s;
 
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_HOST, addr,
-				ifname, port, tref.u32);
+	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, pif, addr, ifname,
+			port, tref.u32);
+
+	if (fwd->mode == FWD_AUTO) {
+		int (*socks)[IP_VERSIONS] = pif == PIF_SPLICE ?
+			tcp_sock_ns : tcp_sock_init_ext;
 
-	if (c->tcp.fwd_in.mode == FWD_AUTO) {
 		if (!addr || inany_v4(addr))
-			tcp_sock_init_ext[port][V4] = s < 0 ? -1 : s;
+			socks[port][V4] = s < 0 ? -1 : s;
 		if (!addr || !inany_v4(addr))
-			tcp_sock_init_ext[port][V6] = s < 0 ? -1 : s;
+			socks[port][V6] = s < 0 ? -1 : s;
 	}
 
 	if (s < 0)
@@ -2549,14 +2558,16 @@ static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr,
 /**
  * tcp_sock_init() - Create listening sockets for a given host ("inbound") port
  * @c:		Execution context
+ * @pif:	Interface to open the socket for (PIF_HOST or PIF_SPLICE)
  * @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: 0 on (partial) success, negative error code on (complete) failure
  */
-int tcp_sock_init(const struct ctx *c, const union inany_addr *addr,
-		  const char *ifname, in_port_t port)
+int tcp_sock_init(const struct ctx *c, uint8_t pif,
+		  const union inany_addr *addr, const char *ifname,
+		  in_port_t port)
 {
 	int r4 = FD_REF_MAX + 1, r6 = FD_REF_MAX + 1;
 
@@ -2564,72 +2575,23 @@ int tcp_sock_init(const struct ctx *c, const union inany_addr *addr,
 
 	if (!addr && c->ifi4 && c->ifi6)
 		/* Attempt to get a dual stack socket */
-		if (tcp_sock_init_one(c, NULL, ifname, port) >= 0)
+		if (tcp_sock_init_one(c, pif, NULL, ifname, port) >= 0)
 			return 0;
 
 	/* Otherwise create a socket per IP version */
 	if ((!addr || inany_v4(addr)) && c->ifi4)
-		r4 = tcp_sock_init_one(c, addr ? addr : &inany_any4,
-				       ifname, port);
+		r4 = tcp_sock_init_one(c, pif,
+				       addr ? addr : &inany_any4, ifname, port);
 
 	if ((!addr || !inany_v4(addr)) && c->ifi6)
-		r6 = tcp_sock_init_one(c, addr ? addr : &inany_any6,
-				       ifname, port);
+		r6 = tcp_sock_init_one(c, pif,
+				       addr ? addr : &inany_any6, ifname, port);
 
 	if (IN_INTERVAL(0, FD_REF_MAX, r4) || IN_INTERVAL(0, FD_REF_MAX, r6))
 		return 0;
 
 	return r4 < 0 ? r4 : r6;
 }
-
-/**
- * tcp_ns_sock_init4() - Init socket to listen for outbound IPv4 connections
- * @c:		Execution context
- * @port:	Port, host order
- */
-static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port)
-{
-	union tcp_listen_epoll_ref tref = {
-		.port = port,
-		.pif = PIF_SPLICE,
-	};
-	int s;
-
-	ASSERT(c->mode == MODE_PASTA);
-
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback4,
-			NULL, port, tref.u32);
-	if (s < 0)
-		s = -1;
-
-	if (c->tcp.fwd_out.mode == FWD_AUTO)
-		tcp_sock_ns[port][V4] = s;
-}
-
-/**
- * tcp_ns_sock_init6() - Init socket to listen for outbound IPv6 connections
- * @c:		Execution context
- * @port:	Port, host order
- */
-static void tcp_ns_sock_init6(const struct ctx *c, in_port_t port)
-{
-	union tcp_listen_epoll_ref tref = {
-		.port = port,
-		.pif = PIF_SPLICE,
-	};
-	int s;
-
-	ASSERT(c->mode == MODE_PASTA);
-
-	s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback6,
-			NULL, port, tref.u32);
-	if (s < 0)
-		s = -1;
-
-	if (c->tcp.fwd_out.mode == FWD_AUTO)
-		tcp_sock_ns[port][V6] = s;
-}
-
 /**
  * tcp_ns_sock_init() - Init socket to listen for spliced outbound connections
  * @c:		Execution context
@@ -2640,9 +2602,9 @@ static void tcp_ns_sock_init(const struct ctx *c, in_port_t port)
 	ASSERT(!c->no_tcp);
 
 	if (c->ifi4)
-		tcp_ns_sock_init4(c, port);
+		tcp_sock_init_one(c, PIF_SPLICE, &inany_loopback4, NULL, port);
 	if (c->ifi6)
-		tcp_ns_sock_init6(c, port);
+		tcp_sock_init_one(c, PIF_SPLICE, &inany_loopback6, NULL, port);
 }
 
 /**
@@ -2845,7 +2807,7 @@ static void tcp_port_rebind(struct ctx *c, bool outbound)
 			if (outbound)
 				tcp_ns_sock_init(c, port);
 			else
-				tcp_sock_init(c, NULL, NULL, port);
+				tcp_sock_init(c, PIF_HOST, NULL, NULL, port);
 		}
 	}
 }
diff --git a/tcp.h b/tcp.h
index 234a8033..fb22bac0 100644
--- a/tcp.h
+++ b/tcp.h
@@ -18,8 +18,9 @@ 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_sock_init(const struct ctx *c, const union inany_addr *addr,
-		  const char *ifname, in_port_t port);
+int tcp_sock_init(const struct ctx *c, uint8_t pif,
+		  const union inany_addr *addr, const char *ifname,
+		  in_port_t port);
 int tcp_init(struct ctx *c);
 void tcp_timer(struct ctx *c, const struct timespec *now);
 void tcp_defer_handler(struct ctx *c);
-- 
2.51.0