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connectd: don't toggle nagle on and off, leave it always off.

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We're doing our own buffering now.

We leave the is_urgent() function for two commits in the future though.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2026-02-16 11:31:21 +10:30
parent c23b7a492d
commit d45bc2d56e
2 changed files with 22 additions and 39 deletions
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21
connectd/connectd.c
View File

@@ -46,6 +46,7 @@
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <signal.h>
#include <sodium.h>
#include <sys/stat.h>
@@ -507,6 +508,19 @@ static bool get_remote_address(struct io_conn *conn,
return true;
}
/* Nagle had a good idea of making networking more efficient by
* inserting a delay, creating a trap for every author of network code
* everywhere.
*/
static void set_tcp_no_delay(int fd)
{
int val = 1;
if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val)) != 0) {
status_broken("setsockopt TCP_NODELAY=1 fd=%u: %s",
fd, strerror(errno));
}
}
/*~ As so common in C, we need to bundle two args into a callback, so we
* allocate a temporary structure to hold them: */
struct conn_in {
@@ -639,6 +653,10 @@ static struct io_plan *connection_in(struct io_conn *conn,
if (!get_remote_address(conn, &conn_in_arg.addr))
return io_close(conn);
/* Don't try to set TCP options on UNIX socket! */
if (conn_in_arg.addr.itype == ADDR_INTERNAL_WIREADDR)
set_tcp_no_delay(io_conn_fd(conn));
conn_in_arg.daemon = daemon;
conn_in_arg.is_websocket = false;
return conn_in(conn, &conn_in_arg);
@@ -1175,6 +1193,9 @@ static void try_connect_one_addr(struct connecting *connect)
goto next;
}
/* Don't try to set TCP options on UNIX socket! */
if (addr->itype == ADDR_INTERNAL_WIREADDR)
set_tcp_no_delay(fd);
connect->connect_attempted = true;
/* This creates the new connection using our fd, with the initialization

40
connectd/multiplex.c
View File

@@ -22,7 +22,6 @@
#include <errno.h>
#include <inttypes.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <wire/peer_wire.h>
#include <wire/wire_io.h>
@@ -294,42 +293,7 @@ void setup_peer_gossip_store(struct peer *peer,
return;
}
/* We're happy for the kernel to batch update and gossip messages, but a
* commitment message, for example, should be instantly sent. There's no
* great way of doing this, unfortunately.
*
* Setting TCP_NODELAY on Linux flushes the socket, which really means
* we'd want to toggle on then off it *after* sending. But Linux has
* TCP_CORK. On FreeBSD, it seems (looking at source) not to, so
* there we'd want to set it before the send, and reenable it
* afterwards. Even if this is wrong on other non-Linux platforms, it
* only means one extra packet.
*/
static void set_urgent_flag(struct peer *peer, bool urgent)
{
int val;
if (urgent == peer->urgent)
return;
/* FIXME: We can't do this on websockets, but we could signal our
* websocket proxy via some magic message to do so! */
if (peer->is_websocket != NORMAL_SOCKET)
return;
val = urgent;
if (setsockopt(io_conn_fd(peer->to_peer),
IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val)) != 0
/* This actually happens in testing, where we blackhole the fd */
&& peer->daemon->dev_disconnect_fd == -1) {
status_broken("setsockopt TCP_NODELAY=1 fd=%u: %s",
io_conn_fd(peer->to_peer),
strerror(errno));
}
peer->urgent = urgent;
}
static bool is_urgent(enum peer_wire type)
static bool UNNEEDED is_urgent(enum peer_wire type)
{
switch (type) {
case WIRE_INIT:
@@ -510,8 +474,6 @@ static struct io_plan *encrypt_and_send(struct peer *peer, const u8 *msg TAKES)
{
int type = fromwire_peektype(msg);
set_urgent_flag(peer, is_urgent(type));
/* Special message type directing us to process batch items. */
if (type == WIRE_PROTOCOL_BATCH_ELEMENT) {
peer->encrypted_peer_out = process_batch_elements(peer, msg);