epoll: Split handling of listening TCP sockets into their own handler

tcp_sock_handler() handles both listening TCP sockets, and connected TCP
sockets, but what it needs to do in those cases has essentially nothing in
common.  Therefore, give listening sockets their own epoll_type value and
dispatch directly to their own handler from the top level.  Furthermore,
the two handlers need essentially entirely different information from the
reference: we re-(ab)used the index field in the tcp_epoll_ref to indicate
the port for the listening socket, but that's not the same meaning.  So,
switch listening sockets to their own reference type which we can lay out
as we please.  That lets us remove the listen and outbound fields from the
normal (connected) tcp_epoll_ref, reducing it to just the connection table
index.

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

1 files changed, 17 insertions, 8 deletions

diff --git a/tcp.h b/tcp.h
index 8eb7782..be296ec 100644
--- a/tcp.h
+++ b/tcp.h
@@ -14,8 +14,9 @@
 struct ctx;
 
 void tcp_timer_handler(struct ctx *c, union epoll_ref ref);
-void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
-		      const struct timespec *now);
+void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
+			const struct timespec *now);
+void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events);
 int tcp_tap_handler(struct ctx *c, int af, const void *addr,
 		    const struct pool *p, const struct timespec *now);
 int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
@@ -30,16 +31,24 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s,
 
 /**
  * union tcp_epoll_ref - epoll reference portion for TCP connections
- * @listen:		Set if this file descriptor is a listening socket
- * @outbound:		Listening socket maps to outbound, spliced connection
- * @index:		Index of connection in table, or port for bound sockets
+ * @index:		Index of connection in table
  * @u32:		Opaque u32 value of reference
  */
 union tcp_epoll_ref {
+	uint32_t index:20;
+	uint32_t u32;
+};
+
+/**
+ * union tcp_listen_epoll_ref - epoll reference portion for TCP listening
+ * @port:	Port number we're forwarding *to* (listening port plus delta)
+ * @ns:		True if listening within the pasta namespace
+ * @u32:	Opaque u32 value of reference
+ */
+union tcp_listen_epoll_ref {
 	struct {
-		uint32_t	listen:1,
-				outbound:1,
-				index:20;
+		in_port_t	port;
+		bool		ns;
 	};
 	uint32_t u32;
 };