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Introduce a function sshfwd_unclean_close(), supplied by ssh.c to

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subsidiary network modules like portfwd.c. To be called when the
subsidiary module experiences a socket error: it sends an emergency
CHANNEL_CLOSE (not just outgoing CHANNEL_EOF), and immediately deletes
the local side of the channel. (I've invented a new channel type in
ssh.c called CHAN_ZOMBIE, for channels whose original local side has
already been thrown away and they're just hanging around waiting to
receive the acknowledging CHANNEL_CLOSE.)

As a result of this and the last few commits, I can now run a port
forwarding session in which a local socket error occurs on a forwarded
port, and PuTTY now handles it apparently correctly, closing both the
SSH channel and the local socket and then actually recognising that
it's OK to terminate when all _other_ channels have been closed.
Previously the channel corresponding to the duff connection would
linger around (because of net_pending_errors never being called), and
keep being selected on (hence chewing CPU), and inhibit program
termination at the end of the session (because not all channels were
closed).

[originally from svn r9364]
This commit is contained in:
Simon Tatham 2011-12-08 19:15:58 +00:00
parent f892af999e
commit 49927f6c4d
3 changed files with 51 additions and 12 deletions
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24
portfwd.c
View File

@ -61,17 +61,19 @@ static int pfd_closing(Plug plug, const char *error_msg, int error_code,
{
struct PFwdPrivate *pr = (struct PFwdPrivate *) plug;
/*
* We have no way to communicate down the forwarded connection,
* so if an error occurred on the socket, we just ignore it
* and treat it like a proper close.
*
* FIXME: except we could initiate a full close here instead of
* just an outgoing EOF? ssh.c currently has no API for that, but
* it could.
*/
if (pr->c)
sshfwd_write_eof(pr->c);
if (error_msg) {
/*
* Socket error. Slam the connection instantly shut.
*/
sshfwd_unclean_close(pr->c);
} else {
/*
* Ordinary EOF received on socket. Send an EOF on the SSH
* channel.
*/
if (pr->c)
sshfwd_write_eof(pr->c);
}
return 1;
}

38
ssh.c
View File

@ -558,7 +558,15 @@ enum { /* channel types */
CHAN_X11,
CHAN_AGENT,
CHAN_SOCKDATA,
CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
/*
* CHAN_ZOMBIE is used to indicate a channel for which we've
* already destroyed the local data source: for instance, if a
* forwarded port experiences a socket error on the local side, we
* immediately destroy its local socket and turn the SSH channel
* into CHAN_ZOMBIE.
*/
CHAN_ZOMBIE
};
/*
@ -4250,6 +4258,34 @@ void sshfwd_write_eof(struct ssh_channel *c)
ssh_channel_try_eof(c);
}
void sshfwd_unclean_close(struct ssh_channel *c)
{
Ssh ssh = c->ssh;
struct Packet *pktout;
if (ssh->state == SSH_STATE_CLOSED)
return;
if (c->closes & CLOSES_SENT_CLOSE)
return;
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_send(ssh, pktout);
c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
switch (c->type) {
case CHAN_X11:
x11_close(c->u.x11.s);
break;
case CHAN_SOCKDATA:
case CHAN_SOCKDATA_DORMANT:
pfd_close(c->u.pfd.s);
break;
}
c->type = CHAN_ZOMBIE;
ssh2_channel_check_close(c);
}
int sshfwd_write(struct ssh_channel *c, char *buf, int len)
{
Ssh ssh = c->ssh;

1
ssh.h
View File

@ -11,6 +11,7 @@ struct ssh_channel;
extern int sshfwd_write(struct ssh_channel *c, char *, int);
extern void sshfwd_write_eof(struct ssh_channel *c);
extern void sshfwd_unclean_close(struct ssh_channel *c);
extern void sshfwd_unthrottle(struct ssh_channel *c, int bufsize);
/*