tcp: Move connection state structures into a shared header

Currently spliced and non-spliced connections use completely independent
tracking structures.  We want to unify these, so as a preliminary step move
the definitions for both variants into a new tcp_conn.h header, shared by
tcp.c and tcp_splice.c.

This requires renaming some #defines with the same name but different
meanings between the two cases.  In the process we correct some places that
are slightly out of sync between the comments and the code for various
event bit names.

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

1 files changed, 25 insertions, 68 deletions

diff --git a/tcp_splice.c b/tcp_splice.c
index 4cc4ad2..cbfab01 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -21,12 +21,12 @@
  *
  * - SPLICE_CONNECT:		connection accepted, connecting to target
  * - SPLICE_ESTABLISHED:	connection to target established
- * - SPLICE_A_OUT_WAIT:		pipe to accepted socket full, wait for EPOLLOUT
- * - SPLICE_B_OUT_WAIT:		pipe to target socket full, wait for EPOLLOUT
- * - SPLICE_A_FIN_RCVD:		FIN (EPOLLRDHUP) seen from accepted socket
- * - SPLICE_B_FIN_RCVD:		FIN (EPOLLRDHUP) seen from target socket
- * - SPLICE_A_FIN_RCVD:		FIN (write shutdown) sent to accepted socket
- * - SPLICE_B_FIN_RCVD:		FIN (write shutdown) sent to target socket
+ * - A_OUT_WAIT:		pipe to accepted socket full, wait for EPOLLOUT
+ * - B_OUT_WAIT:		pipe to target socket full, wait for EPOLLOUT
+ * - A_FIN_RCVD:		FIN (EPOLLRDHUP) seen from accepted socket
+ * - B_FIN_RCVD:		FIN (EPOLLRDHUP) seen from target socket
+ * - A_FIN_RCVD:		FIN (write shutdown) sent to accepted socket
+ * - B_FIN_RCVD:		FIN (write shutdown) sent to target socket
  *
  * #syscalls:pasta pipe2|pipe fcntl armv6l:fcntl64 armv7l:fcntl64 ppc64:fcntl64
  */
@@ -52,6 +52,8 @@
 #include "log.h"
 #include "tcp_splice.h"
 
+#include "tcp_conn.h"
+
 #define MAX_PIPE_SIZE			(8UL * 1024 * 1024)
 #define TCP_SPLICE_PIPE_POOL_SIZE	16
 #define TCP_SPLICE_CONN_PRESSURE	30	/* % of splice_conn_count */
@@ -66,52 +68,7 @@ extern int ns_sock_pool6		[TCP_SOCK_POOL_SIZE];
 /* Pool of pre-opened pipes */
 static int splice_pipe_pool		[TCP_SPLICE_PIPE_POOL_SIZE][2][2];
 
-/**
- * struct tcp_splice_conn - Descriptor for a spliced TCP connection
- * @a:			File descriptor number of socket for accepted connection
- * @pipe_a_b:		Pipe ends for splice() from @a to @b
- * @b:			File descriptor number of peer connected socket
- * @pipe_b_a:		Pipe ends for splice() from @b to @a
- * @events:		Events observed/actions performed on connection
- * @flags:		Connection flags (attributes, not events)
- * @a_read:		Bytes read from @a (not fully written to @b in one shot)
- * @a_written:		Bytes written to @a (not fully written from one @b read)
- * @b_read:		Bytes read from @b (not fully written to @a in one shot)
- * @b_written:		Bytes written to @b (not fully written from one @a read)
-*/
-struct tcp_splice_conn {
-	int a;
-	int pipe_a_b[2];
-	int b;
-	int pipe_b_a[2];
-
-	uint8_t events;
-#define CLOSED				0
-#define CONNECT				BIT(0)
-#define ESTABLISHED			BIT(1)
-#define A_OUT_WAIT			BIT(2)
-#define B_OUT_WAIT			BIT(3)
-#define A_FIN_RCVD			BIT(4)
-#define B_FIN_RCVD			BIT(5)
-#define A_FIN_SENT			BIT(6)
-#define B_FIN_SENT			BIT(7)
-
-	uint8_t flags;
-#define SOCK_V6				BIT(0)
-#define IN_EPOLL			BIT(1)
-#define RCVLOWAT_SET_A			BIT(2)
-#define RCVLOWAT_SET_B			BIT(3)
-#define RCVLOWAT_ACT_A			BIT(4)
-#define RCVLOWAT_ACT_B			BIT(5)
-#define CLOSING				BIT(6)
-
-	uint32_t a_read;
-	uint32_t a_written;
-	uint32_t b_read;
-	uint32_t b_written;
-};
-
-#define CONN_V6(x)			(x->flags & SOCK_V6)
+#define CONN_V6(x)			(x->flags & SPLICE_V6)
 #define CONN_V4(x)			(!CONN_V6(x))
 #define CONN_HAS(conn, set)		((conn->events & (set)) == (set))
 #define CONN(index)			(tc_splice + (index))
@@ -122,13 +79,13 @@ static struct tcp_splice_conn tc_splice[TCP_SPLICE_MAX_CONNS];
 
 /* Display strings for connection events */
 static const char *tcp_splice_event_str[] __attribute((__unused__)) = {
-	"CONNECT", "ESTABLISHED", "A_OUT_WAIT", "B_OUT_WAIT",
+	"SPLICE_CONNECT", "SPLICE_ESTABLISHED", "A_OUT_WAIT", "B_OUT_WAIT",
 	"A_FIN_RCVD", "B_FIN_RCVD", "A_FIN_SENT", "B_FIN_SENT",
 };
 
 /* Display strings for connection flags */
 static const char *tcp_splice_flag_str[] __attribute((__unused__)) = {
-	"SOCK_V6", "IN_EPOLL", "RCVLOWAT_SET_A", "RCVLOWAT_SET_B",
+	"SPLICE_V6", "SPLICE_IN_EPOLL", "RCVLOWAT_SET_A", "RCVLOWAT_SET_B",
 	"RCVLOWAT_ACT_A", "RCVLOWAT_ACT_B", "CLOSING",
 };
 
@@ -143,12 +100,12 @@ static void tcp_splice_conn_epoll_events(uint16_t events,
 {
 	*a = *b = 0;
 
-	if (events & ESTABLISHED) {
+	if (events & SPLICE_ESTABLISHED) {
 		if (!(events & B_FIN_SENT))
 			*a = EPOLLIN | EPOLLRDHUP;
 		if (!(events & A_FIN_SENT))
 			*b = EPOLLIN | EPOLLRDHUP;
-	} else if (events & CONNECT) {
+	} else if (events & SPLICE_CONNECT) {
 		*b = EPOLLOUT;
 	}
 
@@ -210,7 +167,7 @@ static void conn_flag_do(const struct ctx *c, struct tcp_splice_conn *conn,
 static int tcp_splice_epoll_ctl(const struct ctx *c,
 				struct tcp_splice_conn *conn)
 {
-	int m = (conn->flags & IN_EPOLL) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
+	int m = (conn->flags & SPLICE_IN_EPOLL) ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
 	union epoll_ref ref_a = { .r.proto = IPPROTO_TCP, .r.s = conn->a,
 				  .r.p.tcp.tcp.splice = 1,
 				  .r.p.tcp.tcp.index = CONN_IDX(conn),
@@ -234,7 +191,7 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,
 	    epoll_ctl(c->epollfd, m, conn->b, &ev_b))
 		goto delete;
 
-	conn->flags |= IN_EPOLL;		/* No need to log this */
+	conn->flags |= SPLICE_IN_EPOLL;		/* No need to log this */
 
 	return 0;
 
@@ -323,7 +280,7 @@ static void tcp_table_splice_compact(struct ctx *c,
  */
 static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
 {
-	if (conn->events & ESTABLISHED) {
+	if (conn->events & SPLICE_ESTABLISHED) {
 		/* Flushing might need to block: don't recycle them. */
 		if (conn->pipe_a_b[0] != -1) {
 			close(conn->pipe_a_b[0]);
@@ -337,7 +294,7 @@ static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
 		}
 	}
 
-	if (conn->events & CONNECT) {
+	if (conn->events & SPLICE_CONNECT) {
 		close(conn->b);
 		conn->b = -1;
 	}
@@ -346,7 +303,7 @@ static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
 	conn->a = -1;
 	conn->a_read = conn->a_written = conn->b_read = conn->b_written = 0;
 
-	conn->events = CLOSED;
+	conn->events = SPLICE_CLOSED;
 	conn->flags = 0;
 	debug("TCP (spliced): index %li, CLOSED", CONN_IDX(conn));
 
@@ -397,8 +354,8 @@ static int tcp_splice_connect_finish(const struct ctx *c,
 		}
 	}
 
-	if (!(conn->events & ESTABLISHED))
-		conn_event(c, conn, ESTABLISHED);
+	if (!(conn->events & SPLICE_ESTABLISHED))
+		conn_event(c, conn, SPLICE_ESTABLISHED);
 
 	return 0;
 }
@@ -466,9 +423,9 @@ static int tcp_splice_connect(const struct ctx *c, struct tcp_splice_conn *conn,
 			close(sock_conn);
 			return ret;
 		}
-		conn_event(c, conn, CONNECT);
+		conn_event(c, conn, SPLICE_CONNECT);
 	} else {
-		conn_event(c, conn, ESTABLISHED);
+		conn_event(c, conn, SPLICE_ESTABLISHED);
 		return tcp_splice_connect_finish(c, conn);
 	}
 
@@ -598,7 +555,7 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 
 		conn = CONN(c->tcp.splice_conn_count++);
 		conn->a = s;
-		conn->flags = ref.r.p.tcp.tcp.v6 ? SOCK_V6 : 0;
+		conn->flags = ref.r.p.tcp.tcp.v6 ? SPLICE_V6 : 0;
 
 		if (tcp_splice_new(c, conn, ref.r.p.tcp.tcp.index,
 				   ref.r.p.tcp.tcp.outbound))
@@ -609,13 +566,13 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 
 	conn = CONN(ref.r.p.tcp.tcp.index);
 
-	if (conn->events == CLOSED)
+	if (conn->events == SPLICE_CLOSED)
 		return;
 
 	if (events & EPOLLERR)
 		goto close;
 
-	if (conn->events == CONNECT) {
+	if (conn->events == SPLICE_CONNECT) {
 		if (!(events & EPOLLOUT))
 			goto close;
 		if (tcp_splice_connect_finish(c, conn))