diff options
| author | djm@openbsd.org <djm@openbsd.org> | 2023-08-28 05:28:43 +0200 |
|---|---|---|
| committer | Damien Miller <djm@mindrot.org> | 2023-08-28 05:34:01 +0200 |
| commit | dce6d80d2ed3cad2c516082682d5f6ca877ef714 (patch) | |
| tree | f938d8cff790af10c6a3097502dfbfa5c728ea01 /PROTOCOL | |
| parent | upstream: Log errors in kex_exchange_identification() with level (diff) | |
| download | openssh-dce6d80d2ed3cad2c516082682d5f6ca877ef714.tar.xz openssh-dce6d80d2ed3cad2c516082682d5f6ca877ef714.zip | |
upstream: Introduce a transport-level ping facility
This adds a pair of SSH transport protocol messages SSH2_MSG_PING/PONG
to implement a ping capability. These messages use numbers in the "local
extensions" number space and are advertised using a "ping@openssh.com"
ext-info message with a string version number of "0".
ok markus@
OpenBSD-Commit-ID: b6b3c4cb2084c62f85a8dc67cf74954015eb547f
Diffstat (limited to 'PROTOCOL')
| -rw-r--r-- | PROTOCOL | 35 |
1 files changed, 34 insertions, 1 deletions
@@ -104,6 +104,39 @@ http://git.libssh.org/users/aris/libssh.git/plain/doc/curve25519-sha256@libssh.o This is identical to curve25519-sha256 as later published in RFC8731. +1.9 transport: ping facility + +OpenSSH implements a transport level ping message SSH2_MSG_PING +and a corresponding SSH2_MSG_PONG reply. + +#define SSH2_MSG_PING 192 +#define SSH2_MSG_PONG 193 + +The ping message is simply: + + byte SSH_MSG_PING + string data + +The reply copies the data (which may be the empty string) from the +ping: + + byte SSH_MSG_PONG + string data + +Replies are sent in order. They are sent immediately except when rekeying +is in progress, in which case they are queued until rekeying completes. + +The server advertises support for these messages using the +SSH2_MSG_EXT_INFO mechanism (RFC8308), with the following message: + + string "ping@openssh.com" + string "0" (version) + +The ping/reply message is implemented at the transport layer rather +than as a named global or channel request to allow pings with very +short packet lengths, which would not be possible with other +approaches. + 2. Connection protocol changes 2.1. connection: Channel write close extension "eow@openssh.com" @@ -712,4 +745,4 @@ master instance and later clients. OpenSSH extends the usual agent protocol. These changes are documented in the PROTOCOL.agent file. -$OpenBSD: PROTOCOL,v 1.48 2022/11/07 01:53:01 dtucker Exp $ +$OpenBSD: PROTOCOL,v 1.49 2023/08/28 03:28:43 djm Exp $ |