- (dtucker) [sftp.c] Expand ifdef for libedit to cover complete_is_remote

[openssh.git] / PROTOCOL

diff --git a/PROTOCOL b/PROTOCOL
index 64b194cd3339dedce5febf3490e6fb57c7e6d153..c4fd57062c295c7e7edec3c04858f7fc45efe16a 100644 (file)
--- a/PROTOCOL
+++ b/PROTOCOL
@@ -9,6 +9,9 @@ http://www.openssh.com/txt/draft-ietf-secsh-filexfer-02.txt
 Features from newer versions of the draft are not supported, unless
 explicitly implemented as extensions described below.
 
+The protocol used by OpenSSH's ssh-agent is described in the file
+PROTOCOL.agent
+
 1. transport: Protocol 2 MAC algorithm "umac-64@openssh.com"
 
 This is a new transport-layer MAC method using the UMAC algorithm
@@ -43,9 +46,9 @@ processes of the condition, e.g. by closing the corresponding file
 descriptor.
 
 OpenSSH implements a channel extension message to perform this
-signalling: "eow@openssh.com" (End Of Write). This message is sent by an
-endpoint when the local output of a channel is closed or experiences a
-write error. The message is formatted as follows:
+signalling: "eow@openssh.com" (End Of Write). This message is sent by
+an endpoint when the local output of a session channel is closed or
+experiences a write error. The message is formatted as follows:
 
        byte            SSH_MSG_CHANNEL_REQUEST
        uint32          recipient channel
@@ -61,6 +64,12 @@ remain open after a "eow@openssh.com" has been sent and more data may
 still be sent in the other direction. This message does not consume
 window space and may be sent even if no window space is available.
 
+NB. due to certain broken SSH implementations aborting upon receipt
+of this message (in contravention of RFC4254 section 5.4), this
+message is only sent to OpenSSH peers (identified by banner).
+Other SSH implementations may be whitelisted to receive this message
+upon request.
+
 4. connection: disallow additional sessions extension
    "no-more-sessions@openssh.com"
 
@@ -84,6 +93,11 @@ connection.
 Note that this is not a general defence against compromised clients
 (that is impossible), but it thwarts a simple attack.
 
+NB. due to certain broken SSH implementations aborting upon receipt
+of this message, the no-more-sessions request is only sent to OpenSSH
+servers (identified by banner). Other SSH implementations may be
+whitelisted to receive this message upon request.
+
 5. connection: Tunnel forward extension "tun@openssh.com"
 
 OpenSSH supports layer 2 and layer 3 tunnelling via the "tun@openssh.com"
@@ -107,10 +121,10 @@ layer 2 frames or layer 3 packets. It may take one of the following values:
        SSH_TUNMODE_ETHERNET     2              /* layer 2 frames */
 
 The "tunnel unit number" specifies the remote interface number, or may
-be zero to allow the server to automatically chose an interface. A server
-that is not willing to open a client-specified unit should refuse the
-request with a SSH_MSG_CHANNEL_OPEN_FAILURE error. On successful open,
-the server should reply with SSH_MSG_CHANNEL_OPEN_SUCCESS.
+be 0x7fffffff to allow the server to automatically chose an interface. A
+server that is not willing to open a client-specified unit should refuse
+the request with a SSH_MSG_CHANNEL_OPEN_FAILURE error. On successful
+open, the server should reply with SSH_MSG_CHANNEL_OPEN_SUCCESS.
 
 Once established the client and server may exchange packet or frames
 over the tunnel channel by encapsulating them in SSH protocol strings
@@ -137,7 +151,7 @@ It may be one of:
 The "packet data" field consists of the IPv4/IPv6 datagram itself
 without any link layer header.
 
-The contents of the "data" field for layer 3 packets is:
+The contents of the "data" field for layer 2 packets is:
 
        uint32                  packet length
        byte[packet length]     frame
@@ -234,7 +248,7 @@ The values of the f_flag bitmask are as follows:
        #define SSH_FXE_STATVFS_ST_RDONLY       0x1     /* read-only */
        #define SSH_FXE_STATVFS_ST_NOSUID       0x2     /* no setuid */
 
-This extension is advertised in the SSH_FXP_VERSION hello with version
-"2".
+Both the "statvfs@openssh.com" and "fstatvfs@openssh.com" extensions are
+advertised in the SSH_FXP_VERSION hello with version "2".
 
-$OpenBSD: PROTOCOL,v 1.8 2008/06/28 07:25:07 djm Exp $
+$OpenBSD: PROTOCOL,v 1.13 2009/12/20 23:20:40 djm Exp $