From ca86726f9f943b2b18e5694b442d3d2e1c0fa903 Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Wed, 25 Jun 2014 23:42:39 +0800
Subject: [PATCH] Improve handling lots of concurrent forwarded connections.
Increase connection backlog, avoid check_close() for channels that haven't
had IO
---
common-channel.c | 13 ++++++++++---
dbutil.c | 2 +-
sysoptions.h | 6 ++++++
3 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/common-channel.c b/common-channel.c
index 91629809..62e4be1c 100644
--- a/common-channel.c
+++ b/common-channel.c
@@ -208,11 +208,14 @@ struct Channel* getchannel() {
/* Iterate through the channels, performing IO if available */
void channelio(fd_set *readfds, fd_set *writefds) {
+ /* Listeners such as TCP, X11, agent-auth */
struct Channel *channel;
unsigned int i;
/* foreach channel */
for (i = 0; i < ses.chansize; i++) {
+ /* Close checking only needs to occur for channels that had IO events */
+ int do_check_close = 0;
channel = ses.channels[i];
if (channel == NULL) {
@@ -224,6 +227,7 @@ void channelio(fd_set *readfds, fd_set *writefds) {
if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) {
TRACE(("send normal readfd"))
send_msg_channel_data(channel, 0);
+ do_check_close = 1;
}
/* read stderr data and send it over the wire */
@@ -231,6 +235,7 @@ void channelio(fd_set *readfds, fd_set *writefds) {
&& FD_ISSET(channel->errfd, readfds)) {
TRACE(("send normal errfd"))
send_msg_channel_data(channel, 1);
+ do_check_close = 1;
}
/* write to program/pipe stdin */
@@ -242,20 +247,22 @@ void channelio(fd_set *readfds, fd_set *writefds) {
check_in_progress(), as it may be NULL */
}
writechannel(channel, channel->writefd, channel->writebuf);
+ do_check_close = 1;
}
/* stderr for client mode */
if (ERRFD_IS_WRITE(channel)
&& channel->errfd >= 0 && FD_ISSET(channel->errfd, writefds)) {
writechannel(channel, channel->errfd, channel->extrabuf);
+ do_check_close = 1;
}
/* handle any channel closing etc */
- check_close(channel);
-
+ if (do_check_close) {
+ check_close(channel);
+ }
}
- /* Listeners such as TCP, X11, agent-auth */
#ifdef USING_LISTENERS
handle_listeners(readfds);
#endif
diff --git a/dbutil.c b/dbutil.c
index 145bc332..2ea52ace 100644
--- a/dbutil.c
+++ b/dbutil.c
@@ -332,7 +332,7 @@ int dropbear_listen(const char* address, const char* port,
continue;
}
- if (listen(sock, 20) < 0) {
+ if (listen(sock, DROPBEAR_LISTEN_BACKLOG) < 0) {
err = errno;
close(sock);
TRACE(("listen() failed"))
diff --git a/sysoptions.h b/sysoptions.h
index a587762f..8a359fb5 100644
--- a/sysoptions.h
+++ b/sysoptions.h
@@ -251,4 +251,10 @@
#define USE_VFORK
#endif /* don't HAVE_FORK */
+#if MAX_UNAUTH_CLIENTS > MAX_CHANNELS
+#define DROPBEAR_LISTEN_BACKLOG MAX_UNAUTH_CLIENTS
+#else
+#define DROPBEAR_LISTEN_BACKLOG MAX_CHANNELS
+#endif
+
/* no include guard for this file */
--
GitLab