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From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v2 08/32] tcp: Add connection union type
Date: Thu, 17 Nov 2022 16:58:44 +1100	[thread overview]
Message-ID: <20221117055908.2782981-9-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221117055908.2782981-1-david@gibson.dropbear.id.au>

Currently, the tables for spliced and non-spliced connections are entirely
separate, with different types in different arrays.  We want to unify them.
As a first step, create a union type which can represent either a spliced
or non-spliced connection.  For them to be distinguishable, the individual
types need to have a common header added, with a bit indicating which type
this structure is.

This comes at the cost of increasing the size of tcp_tap_conn to over one
(64 byte) cacheline.  This isn't ideal, but it makes things simpler for now
and we'll re-optimize this later.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tcp.c        |  4 ++++
 tcp_conn.h   | 30 ++++++++++++++++++++++++++++++
 tcp_splice.c |  2 ++
 3 files changed, 36 insertions(+)

diff --git a/tcp.c b/tcp.c
index 189041c..05eed85 100644
--- a/tcp.c
+++ b/tcp.c
@@ -288,6 +288,7 @@
 #include <sys/uio.h>
 #include <unistd.h>
 #include <time.h>
+#include <assert.h>
 
 #include <linux/tcp.h> /* For struct tcp_info */
 
@@ -601,6 +602,7 @@ static inline struct tcp_tap_conn *conn_at_idx(int index)
 {
 	if ((index < 0) || (index >= TCP_MAX_CONNS))
 		return NULL;
+	assert(!(CONN(index)->c.spliced));
 	return CONN(index);
 }
 
@@ -2096,6 +2098,7 @@ static void tcp_conn_from_tap(struct ctx *c, int af, const void *addr,
 	}
 
 	conn = CONN(c->tcp.conn_count++);
+	conn->c.spliced = false;
 	conn->sock = s;
 	conn->timer = -1;
 	conn_event(c, conn, TAP_SYN_RCVD);
@@ -2764,6 +2767,7 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
 		return;
 
 	conn = CONN(c->tcp.conn_count++);
+	conn->c.spliced = false;
 	conn->sock = s;
 	conn->timer = -1;
 	conn->ws_to_tap = conn->ws_from_tap = 0;
diff --git a/tcp_conn.h b/tcp_conn.h
index db4c2d9..39d104a 100644
--- a/tcp_conn.h
+++ b/tcp_conn.h
@@ -11,8 +11,19 @@
 
 #define TCP_HASH_BUCKET_BITS		(TCP_CONN_INDEX_BITS + 1)
 
+/**
+ * struct tcp_conn_common - Common fields for spliced and non-spliced
+ * @spliced:		Is this a spliced connection?
+ */
+struct tcp_conn_common {
+	bool spliced	:1;
+};
+
+extern const char *tcp_common_flag_str[];
+
 /**
  * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced)
+ * @c:			Fields common with tcp_splice_conn
  * @next_index:		Connection index of next item in hash chain, -1 for none
  * @tap_mss:		MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS
  * @sock:		Socket descriptor number
@@ -40,6 +51,9 @@
  * @seq_init_from_tap:	Initial sequence number from tap
  */
 struct tcp_tap_conn {
+	/* Must be first element to match tcp_splice_conn */
+	struct tcp_conn_common c;
+
 	int	 	next_index	:TCP_CONN_INDEX_BITS + 2;
 
 #define TCP_RETRANS_BITS		3
@@ -122,6 +136,7 @@ struct tcp_tap_conn {
 
 /**
  * struct tcp_splice_conn - Descriptor for a spliced TCP connection
+ * @c:			Fields common with tcp_tap_conn
  * @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
@@ -134,6 +149,9 @@ struct tcp_tap_conn {
  * @b_written:		Bytes written to @b (not fully written from one @a read)
 */
 struct tcp_splice_conn {
+	/* Must be first element to match tcp_tap_conn */
+	struct tcp_conn_common c;
+
 	int a;
 	int pipe_a_b[2];
 	int b;
@@ -165,4 +183,16 @@ struct tcp_splice_conn {
 	uint32_t b_written;
 };
 
+/**
+ * union tcp_conn - Descriptor for a TCP connection (spliced or non-spliced)
+ * @c:			Fields common between all variants
+ * @tap:		Fields specific to non-spliced connections
+ * @splice:		Fields specific to spliced connections
+*/
+union tcp_conn {
+	struct tcp_conn_common c;
+	struct tcp_tap_conn tap;
+	struct tcp_splice_conn splice;
+};
+
 #endif /* TCP_CONN_H */
diff --git a/tcp_splice.c b/tcp_splice.c
index cbfab01..d8be91b 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -46,6 +46,7 @@
 #include <sys/epoll.h>
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <assert.h>
 
 #include "util.h"
 #include "passt.h"
@@ -554,6 +555,7 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 		}
 
 		conn = CONN(c->tcp.splice_conn_count++);
+		conn->c.spliced = true;
 		conn->a = s;
 		conn->flags = ref.r.p.tcp.tcp.v6 ? SPLICE_V6 : 0;
 
-- 
@@ -46,6 +46,7 @@
 #include <sys/epoll.h>
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <assert.h>
 
 #include "util.h"
 #include "passt.h"
@@ -554,6 +555,7 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 		}
 
 		conn = CONN(c->tcp.splice_conn_count++);
+		conn->c.spliced = true;
 		conn->a = s;
 		conn->flags = ref.r.p.tcp.tcp.v6 ? SPLICE_V6 : 0;
 
-- 
2.38.1


  parent reply	other threads:[~2022-11-17  5:59 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-17  5:58 [PATCH v2 00/32] Use dual stack sockets to listen for inbound TCP connections David Gibson
2022-11-17  5:58 ` [PATCH v2 01/32] clang-tidy: Suppress warning about assignments in if statements David Gibson
2022-11-17  5:58 ` [PATCH v2 02/32] style: Minor corrections to function comments David Gibson
2022-11-17  5:58 ` [PATCH v2 03/32] tcp_splice: #include tcp_splice.h in tcp_splice.c David Gibson
2022-11-17  5:58 ` [PATCH v2 04/32] tcp: Remove unused TCP_MAX_SOCKS constant David Gibson
2022-11-17  5:58 ` [PATCH v2 05/32] tcp: Better helpers for converting between connection pointer and index David Gibson
2022-11-17  5:58 ` [PATCH v2 06/32] tcp_splice: Helpers for converting from index to/from tcp_splice_conn David Gibson
2022-11-17  5:58 ` [PATCH v2 07/32] tcp: Move connection state structures into a shared header David Gibson
2022-11-17  5:58 ` David Gibson [this message]
2022-11-18  0:25   ` [PATCH v2 08/32] tcp: Add connection union type Stefano Brivio
2022-11-18  1:10     ` David Gibson
2022-11-19  8:39       ` Stefano Brivio
2022-11-17  5:58 ` [PATCH v2 09/32] tcp: Improved helpers to update connections after moving David Gibson
2022-11-17  5:58 ` [PATCH v2 10/32] tcp: Unify spliced and non-spliced connection tables David Gibson
2022-11-17  5:58 ` [PATCH v2 11/32] tcp: Unify tcp_defer_handler and tcp_splice_defer_handler() David Gibson
2022-11-17  5:58 ` [PATCH v2 12/32] tcp: Partially unify tcp_timer() and tcp_splice_timer() David Gibson
2022-11-17  5:58 ` [PATCH v2 13/32] tcp: Unify the IN_EPOLL flag David Gibson
2022-11-17  5:58 ` [PATCH v2 14/32] tcp: Separate helpers to create ns listening sockets David Gibson
2022-11-17  5:58 ` [PATCH v2 15/32] tcp: Unify part of spliced and non-spliced conn_from_sock path David Gibson
2022-11-17  5:58 ` [PATCH v2 16/32] tcp: Use the same sockets to listen for spliced and non-spliced connections David Gibson
2022-11-17  5:58 ` [PATCH v2 17/32] tcp: Remove splice from tcp_epoll_ref David Gibson
2022-11-17  5:58 ` [PATCH v2 18/32] tcp: Don't store hash bucket in connection structures David Gibson
2022-11-17  5:58 ` [PATCH v2 19/32] inany: Helper functions for handling addresses which could be IPv4 or IPv6 David Gibson
2022-11-17  5:58 ` [PATCH v2 20/32] tcp: Hash IPv4 and IPv4-mapped-IPv6 addresses the same David Gibson
2022-11-17  5:58 ` [PATCH v2 21/32] tcp: Take tcp_hash_insert() address from struct tcp_conn David Gibson
2022-11-17  5:58 ` [PATCH v2 22/32] tcp: Simplify tcp_hash_match() to take an inany_addr David Gibson
2022-11-17  5:58 ` [PATCH v2 23/32] tcp: Unify initial sequence number calculation for IPv4 and IPv6 David Gibson
2022-11-17  5:59 ` [PATCH v2 24/32] tcp: Have tcp_seq_init() take its parameters from struct tcp_conn David Gibson
2022-11-17  5:59 ` [PATCH v2 25/32] tcp: Fix small errors in tcp_seq_init() time handling David Gibson
2022-11-17  5:59 ` [PATCH v2 26/32] tcp: Remove v6 flag from tcp_epoll_ref David Gibson
2022-11-17  5:59 ` [PATCH v2 27/32] tcp: NAT IPv4-mapped IPv6 addresses like IPv4 addresses David Gibson
2022-11-17  5:59 ` [PATCH v2 28/32] tcp_splice: Allow splicing of connections from IPv4-mapped loopback David Gibson
2022-11-17  5:59 ` [PATCH v2 29/32] tcp: Consolidate tcp_sock_init[46] David Gibson
2022-11-17  5:59 ` [PATCH v2 30/32] util: Allow sock_l4() to open dual stack sockets David Gibson
2022-11-17  5:59 ` [PATCH v2 31/32] util: Always return -1 on error in sock_l4() David Gibson
2022-11-17  5:59 ` [PATCH v2 32/32] tcp: Use dual stack sockets for port forwarding when possible David Gibson
2022-11-25  9:22 ` [PATCH v2 00/32] Use dual stack sockets to listen for inbound TCP connections Stefano Brivio

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