tcp: Refactor to use events instead of states, split out spliced implementation

Using events and flags instead of states makes the implementation
much more straightforward: actions are mostly centered on events
that occurred on the connection rather than states.

An example is given by the ESTABLISHED_SOCK_FIN_SENT and
FIN_WAIT_1_SOCK_FIN abominations: we don't actually care about
which side started closing the connection to handle closing of
connection halves.

Split out the spliced implementation, as it has very little in
common with the "regular" TCP path.

Refactor things here and there to improve clarity. Add helpers
to trace where resets and flag settings come from.

No functional changes intended.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/tcp.h b/tcp.h
index 512ee76..b4e3fde 100644
--- a/tcp.h
+++ b/tcp.h
@@ -11,6 +11,8 @@
 #define TCP_MAX_CONNS			(128 * 1024)
 #define TCP_MAX_SOCKS			(TCP_MAX_CONNS + USHRT_MAX * 2)
 
+#define TCP_SOCK_POOL_SIZE		32
+
 struct ctx;
 
 void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
@@ -19,7 +21,9 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
 		    struct tap_l4_msg *msg, int count, struct timespec *now);
 int tcp_sock_init(struct ctx *c, struct timespec *now);
 void tcp_timer(struct ctx *c, struct timespec *now);
-void tcp_defer_handler(struct ctx *c);
+void tcp_defer_handler(struct ctx *c, struct timespec *now);
+
+void tcp_sock_set_bufsize(struct ctx *c, int s);
 void tcp_update_l2_buf(unsigned char *eth_d, unsigned char *eth_s,
 		       const uint32_t *ip_da);
 void tcp_remap_to_tap(in_port_t port, in_port_t delta);
@@ -46,7 +50,7 @@ union tcp_epoll_ref {
 /**
  * struct tcp_ctx - Execution context for TCP routines
  * @hash_secret:	128-bit secret for hash functions, ISN and hash table
- * @tap_conn_count:	Count of tap connections in connection table
+ * @conn_count:		Count of connections (not spliced) in connection table
  * @splice_conn_count:	Count of spliced connections in connection table
  * @port_to_tap:	Ports bound host-side, packets to tap or spliced
  * @init_detect_ports:	If set, periodically detect ports bound in init
@@ -60,7 +64,7 @@ union tcp_epoll_ref {
  */
 struct tcp_ctx {
 	uint64_t hash_secret[2];
-	int tap_conn_count;
+	int conn_count;
 	int splice_conn_count;
 	uint8_t port_to_tap	[USHRT_MAX / 8];
 	int init_detect_ports;