[PATCH v5 04/19] tcp: Remove interim 'tapside' field from connection

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

We recently introduced this field to keep track of which side of a TCP flow
is the guest/tap facing one.  Now that we generically record which pif each
side of each flow is connected to, we can easily derive that, and no longer
need to keep track of it explicitly.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tcp.c      | 12 ++++++------
 tcp_conn.h |  2 --
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/tcp.c b/tcp.c
index 48aae30..3895f3f 100644
--- a/tcp.c
+++ b/tcp.c
@@ -368,6 +368,8 @@
 #define OPT_SACK	5
 #define OPT_TS		8
 
+#define TAPSIDE(conn_)	((conn_)->f.pif[1] == PIF_TAP)
+
 #define CONN_V4(conn)		(!!inany_v4(&(conn)->faddr))
 #define CONN_V6(conn)		(!CONN_V4(conn))
 #define CONN_IS_CLOSING(conn)						\
@@ -577,7 +579,7 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 {
 	int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 	union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock,
-				.flowside = FLOW_SIDX(conn, !conn->tapside), };
+		                .flowside = FLOW_SIDX(conn, !TAPSIDE(conn)), };
 	struct epoll_event ev = { .data.u64 = ref.u64 };
 
 	if (conn->events == CLOSED) {
@@ -1130,8 +1132,8 @@ static uint64_t tcp_conn_hash(const struct ctx *c,
 static inline unsigned tcp_hash_probe(const struct ctx *c,
 				      const struct tcp_tap_conn *conn)
 {
-	flow_sidx_t sidx = FLOW_SIDX(conn, conn->tapside);
 	unsigned b = tcp_conn_hash(c, conn) % TCP_HASH_TABLE_SIZE;
+	flow_sidx_t sidx = FLOW_SIDX(conn, TAPSIDE(conn));
 
 	/* Linear probing */
 	while (!flow_sidx_eq(tc_hash[b], FLOW_SIDX_NONE) &&
@@ -1150,7 +1152,7 @@ static void tcp_hash_insert(const struct ctx *c, struct tcp_tap_conn *conn)
 {
 	unsigned b = tcp_hash_probe(c, conn);
 
-	tc_hash[b] = FLOW_SIDX(conn, conn->tapside);
+	tc_hash[b] = FLOW_SIDX(conn, TAPSIDE(conn));
 	flow_dbg(conn, "hash table insert: sock %i, bucket: %u", conn->sock, b);
 }
 
@@ -2006,7 +2008,6 @@ static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
 
 	flow_forward(flow, PIF_HOST);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
-	conn->tapside = INISIDE;
 	conn->sock = s;
 	conn->timer = -1;
 	conn_event(c, conn, TAP_SYN_RCVD);
@@ -2730,7 +2731,6 @@ static void tcp_tap_conn_from_sock(struct ctx *c, in_port_t dstport,
 	flow_forward(flow, PIF_TAP);
 	conn = FLOW_SET_TYPE(flow, FLOW_TCP, tcp);
 
-	conn->tapside = FWDSIDE;
 	conn->sock = s;
 	conn->timer = -1;
 	conn->ws_to_tap = conn->ws_from_tap = 0;
@@ -2889,7 +2889,7 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events)
 	struct tcp_tap_conn *conn = CONN(ref.flowside.flow);
 
 	ASSERT(conn->f.type == FLOW_TCP);
-	ASSERT(ref.flowside.side == !conn->tapside);
+	ASSERT(conn->f.pif[ref.flowside.side] != PIF_TAP);
 
 	if (conn->events == CLOSED)
 		return;
diff --git a/tcp_conn.h b/tcp_conn.h
index 5df0076..1a07dd5 100644
--- a/tcp_conn.h
+++ b/tcp_conn.h
@@ -13,7 +13,6 @@
  * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
  * @f:			Generic flow information
  * @in_epoll:		Is the connection in the epoll set?
- * @tapside:		Which side of the flow faces the tap/guest interface
  * @tap_mss:		MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
  * @sock:		Socket descriptor number
  * @events:		Connection events, implying connection states
@@ -40,7 +39,6 @@ struct tcp_tap_conn {
 	struct flow_common f;
 
 	bool		in_epoll	:1;
-	unsigned	tapside		:1;
 
 #define TCP_RETRANS_BITS		3
 	unsigned int	retrans		:TCP_RETRANS_BITS;
-- 
@@ -13,7 +13,6 @@
  * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
  * @f:			Generic flow information
  * @in_epoll:		Is the connection in the epoll set?
- * @tapside:		Which side of the flow faces the tap/guest interface
  * @tap_mss:		MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
  * @sock:		Socket descriptor number
  * @events:		Connection events, implying connection states
@@ -40,7 +39,6 @@ struct tcp_tap_conn {
 	struct flow_common f;
 
 	bool		in_epoll	:1;
-	unsigned	tapside		:1;
 
 #define TCP_RETRANS_BITS		3
 	unsigned int	retrans		:TCP_RETRANS_BITS;
-- 
2.45.0