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 32/32] tcp: Use dual stack sockets for port forwarding when possible
Date: Thu, 17 Nov 2022 16:59:08 +1100 [thread overview]
Message-ID: <20221117055908.2782981-33-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221117055908.2782981-1-david@gibson.dropbear.id.au>
Platforms like Linux allow IPv6 sockets to listen for IPv4 connections as
well as native IPv6 connections. By doing this we halve the number of
listening sockets we need for TCP (assuming passt/pasta is listening on the
same ports for IPv4 and IPv6). When forwarding many ports (e.g. -t all)
this can significantly reduce the amount of kernel memory that passt
consumes.
When forwarding all TCP and UDP ports for both IPv4 and IPv6 (-t all
-u all), this reduces kernel memory usage from ~677MiB to ~487MiB
(kernel version 6.0.8 on Fedora 37, x86_64).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/tcp.c b/tcp.c
index c199863..8044617 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2996,8 +2996,12 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
s = sock_l4(c, af, IPPROTO_TCP, addr, ifname, port, tref.u32);
- if (c->tcp.fwd_in.mode == FWD_AUTO)
- tcp_sock_init_ext[port][(af == AF_INET) ? V4 : V6] = s;
+ if (c->tcp.fwd_in.mode == FWD_AUTO) {
+ if (af == AF_INET || af == AF_UNSPEC)
+ tcp_sock_init_ext[port][V4] = s;
+ if (af == AF_INET6 || af == AF_UNSPEC)
+ tcp_sock_init_ext[port][V6] = s;
+ }
if (s < 0)
return -1;
@@ -3017,6 +3021,12 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
void tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
const char *ifname, in_port_t port)
{
+ if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
+ /* Attempt to get a dual stack socket */
+ if (tcp_sock_init_af(c, AF_UNSPEC, port, addr, ifname) >= 0)
+ return;
+
+ /* Otherwise create a socket per IP version */
if ((af == AF_INET || af == AF_UNSPEC) && c->ifi4)
tcp_sock_init_af(c, AF_INET, port, addr, ifname);
if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6)
--
@@ -2996,8 +2996,12 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
s = sock_l4(c, af, IPPROTO_TCP, addr, ifname, port, tref.u32);
- if (c->tcp.fwd_in.mode == FWD_AUTO)
- tcp_sock_init_ext[port][(af == AF_INET) ? V4 : V6] = s;
+ if (c->tcp.fwd_in.mode == FWD_AUTO) {
+ if (af == AF_INET || af == AF_UNSPEC)
+ tcp_sock_init_ext[port][V4] = s;
+ if (af == AF_INET6 || af == AF_UNSPEC)
+ tcp_sock_init_ext[port][V6] = s;
+ }
if (s < 0)
return -1;
@@ -3017,6 +3021,12 @@ static int tcp_sock_init_af(const struct ctx *c, int af, in_port_t port,
void tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
const char *ifname, in_port_t port)
{
+ if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
+ /* Attempt to get a dual stack socket */
+ if (tcp_sock_init_af(c, AF_UNSPEC, port, addr, ifname) >= 0)
+ return;
+
+ /* Otherwise create a socket per IP version */
if ((af == AF_INET || af == AF_UNSPEC) && c->ifi4)
tcp_sock_init_af(c, AF_INET, port, addr, ifname);
if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6)
--
2.38.1
next prev 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 ` [PATCH v2 08/32] tcp: Add connection union type David Gibson
2022-11-18 0:25 ` 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 ` David Gibson [this message]
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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