LIBSSH2_API int
libssh2_keepalive_send (LIBSSH2_SESSION *session,
int *seconds_to_next)
{
time_t now;
if (!session->keepalive_interval) {
if (seconds_to_next)
*seconds_to_next = 0;
return 0;
}
now = time (NULL);
if (session->keepalive_last_sent + session->keepalive_interval <= now) {
/* Format is "SSH_MSG_GLOBAL_REQUEST || 4-byte len || str || want-reply". */
unsigned char keepalive_data[]
= "\x50\x00\x00\x00\[email protected]";
size_t len = sizeof (keepalive_data) - 1;
int rc;
keepalive_data[len - 1] = session->keepalive_want_reply;
rc = _libssh2_transport_write(session, keepalive_data, len);
/* Silently ignore PACKET_EAGAIN here: if the write buffer is
already full, sending another keepalive is not useful. */
if (rc && rc != LIBSSH2_ERROR_EAGAIN) {
_libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send keepalive message");
return rc;
}
session->keepalive_last_sent = now;
if (seconds_to_next)
*seconds_to_next = session->keepalive_interval;
} else if (seconds_to_next) {
*seconds_to_next = session->keepalive_last_sent
+ session->keepalive_interval - now;
}
return 0;
}
/*
* libssh2_packet_queue_listener
*
* Queue a connection request for a listener
*/
static inline int
packet_queue_listener(LIBSSH2_SESSION * session, unsigned char *data,
unsigned long datalen,
packet_queue_listener_state_t * listen_state)
{
/*
* Look for a matching listener
*/
unsigned char *s = data + (sizeof("forwarded-tcpip") - 1) + 5;
/* 17 = packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */
unsigned long packet_len = 17 + (sizeof(FwdNotReq) - 1);
unsigned char *p;
LIBSSH2_LISTENER *listen = session->listeners;
char failure_code = 1; /* SSH_OPEN_ADMINISTRATIVELY_PROHIBITED */
int rc;
(void) datalen;
if (listen_state->state == libssh2_NB_state_idle) {
listen_state->sender_channel = _libssh2_ntohu32(s);
s += 4;
listen_state->initial_window_size = _libssh2_ntohu32(s);
s += 4;
listen_state->packet_size = _libssh2_ntohu32(s);
s += 4;
listen_state->host_len = _libssh2_ntohu32(s);
s += 4;
listen_state->host = s;
s += listen_state->host_len;
listen_state->port = _libssh2_ntohu32(s);
s += 4;
listen_state->shost_len = _libssh2_ntohu32(s);
s += 4;
listen_state->shost = s;
s += listen_state->shost_len;
listen_state->sport = _libssh2_ntohu32(s);
s += 4;
_libssh2_debug(session, LIBSSH2_DBG_CONN,
"Remote received connection from %s:%ld to %s:%ld",
listen_state->shost, listen_state->sport,
listen_state->host, listen_state->port);
listen_state->state = libssh2_NB_state_allocated;
}
if (listen_state->state != libssh2_NB_state_sent) {
while (listen) {
if ((listen->port == (int) listen_state->port) &&
(strlen(listen->host) == listen_state->host_len) &&
(memcmp
(listen->host, listen_state->host,
listen_state->host_len) == 0)) {
/* This is our listener */
LIBSSH2_CHANNEL *channel, *last_queued = listen->queue;
last_queued = listen->queue;
if (listen_state->state == libssh2_NB_state_allocated) {
if (listen->queue_maxsize &&
(listen->queue_maxsize <= listen->queue_size)) {
/* Queue is full */
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
_libssh2_debug(session, LIBSSH2_DBG_CONN,
"Listener queue full, ignoring");
listen_state->state = libssh2_NB_state_sent;
break;
}
channel = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_CHANNEL));
if (!channel) {
libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate a channel for new connection",
0);
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
listen_state->state = libssh2_NB_state_sent;
break;
}
memset(channel, 0, sizeof(LIBSSH2_CHANNEL));
channel->session = session;
channel->channel_type_len = sizeof("forwarded-tcpip") - 1;
channel->channel_type = LIBSSH2_ALLOC(session,
channel->
channel_type_len +
1);
if (!channel->channel_type) {
libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate a channel for new connection",
0);
LIBSSH2_FREE(session, channel);
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
listen_state->state = libssh2_NB_state_sent;
break;
}
memcpy(channel->channel_type, "forwarded-tcpip",
channel->channel_type_len + 1);
channel->remote.id = listen_state->sender_channel;
channel->remote.window_size_initial =
LIBSSH2_CHANNEL_WINDOW_DEFAULT;
channel->remote.window_size =
LIBSSH2_CHANNEL_WINDOW_DEFAULT;
channel->remote.packet_size =
LIBSSH2_CHANNEL_PACKET_DEFAULT;
channel->local.id = _libssh2_channel_nextid(session);
channel->local.window_size_initial =
listen_state->initial_window_size;
channel->local.window_size =
listen_state->initial_window_size;
channel->local.packet_size = listen_state->packet_size;
_libssh2_debug(session, LIBSSH2_DBG_CONN,
"Connection queued: channel %lu/%lu win %lu/%lu packet %lu/%lu",
channel->local.id, channel->remote.id,
channel->local.window_size,
channel->remote.window_size,
channel->local.packet_size,
channel->remote.packet_size);
p = listen_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION;
_libssh2_htonu32(p, channel->remote.id);
p += 4;
_libssh2_htonu32(p, channel->local.id);
p += 4;
_libssh2_htonu32(p, channel->remote.window_size_initial);
p += 4;
_libssh2_htonu32(p, channel->remote.packet_size);
p += 4;
listen_state->state = libssh2_NB_state_created;
}
if (listen_state->state == libssh2_NB_state_created) {
rc = _libssh2_transport_write(session, listen_state->packet,
17);
if (rc == PACKET_EAGAIN) {
return PACKET_EAGAIN;
} else if (rc) {
libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send channel open confirmation",
0);
listen_state->state = libssh2_NB_state_idle;
return -1;
}
/* Link the channel into the end of the queue list */
if (!last_queued) {
listen->queue = channel;
listen_state->state = libssh2_NB_state_idle;
return 0;
}
while (last_queued->next) {
last_queued = last_queued->next;
}
last_queued->next = channel;
channel->prev = last_queued;
listen->queue_size++;
listen_state->state = libssh2_NB_state_idle;
return 0;
}
}
listen = listen->next;
}
listen_state->state = libssh2_NB_state_sent;
}
/* We're not listening to you */
{
p = listen_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE;
_libssh2_htonu32(p, listen_state->sender_channel);
p += 4;
_libssh2_htonu32(p, failure_code);
p += 4;
_libssh2_htonu32(p, sizeof(FwdNotReq) - 1);
p += 4;
memcpy(s, FwdNotReq, sizeof(FwdNotReq) - 1);
p += sizeof(FwdNotReq) - 1;
_libssh2_htonu32(p, 0);
rc = _libssh2_transport_write(session, listen_state->packet,
packet_len);
if (rc == PACKET_EAGAIN) {
return PACKET_EAGAIN;
} else if (rc) {
libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send open failure", 0);
listen_state->state = libssh2_NB_state_idle;
return -1;
}
listen_state->state = libssh2_NB_state_idle;
return 0;
}
}
/*
* packet_x11_open
*
* Accept a forwarded X11 connection
*/
static inline int
packet_x11_open(LIBSSH2_SESSION * session, unsigned char *data,
unsigned long datalen,
packet_x11_open_state_t * x11open_state)
{
int failure_code = 2; /* SSH_OPEN_CONNECT_FAILED */
unsigned char *s = data + (sizeof("x11") - 1) + 5;
/* 17 = packet_type(1) + channel(4) + reason(4) + descr(4) + lang(4) */
unsigned long packet_len = 17 + (sizeof(X11FwdUnAvil) - 1);
unsigned char *p;
LIBSSH2_CHANNEL *channel;
int rc;
(void) datalen;
if (x11open_state->state == libssh2_NB_state_idle) {
x11open_state->sender_channel = _libssh2_ntohu32(s);
s += 4;
x11open_state->initial_window_size = _libssh2_ntohu32(s);
s += 4;
x11open_state->packet_size = _libssh2_ntohu32(s);
s += 4;
x11open_state->shost_len = _libssh2_ntohu32(s);
s += 4;
x11open_state->shost = s;
s += x11open_state->shost_len;
x11open_state->sport = _libssh2_ntohu32(s);
s += 4;
_libssh2_debug(session, LIBSSH2_DBG_CONN,
"X11 Connection Received from %s:%ld on channel %lu",
x11open_state->shost, x11open_state->sport,
x11open_state->sender_channel);
x11open_state->state = libssh2_NB_state_allocated;
}
if (session->x11) {
if (x11open_state->state == libssh2_NB_state_allocated) {
channel = LIBSSH2_ALLOC(session, sizeof(LIBSSH2_CHANNEL));
if (!channel) {
libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate a channel for new connection",
0);
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
goto x11_exit;
}
memset(channel, 0, sizeof(LIBSSH2_CHANNEL));
channel->session = session;
channel->channel_type_len = sizeof("x11") - 1;
channel->channel_type = LIBSSH2_ALLOC(session,
channel->channel_type_len +
1);
if (!channel->channel_type) {
libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate a channel for new connection",
0);
LIBSSH2_FREE(session, channel);
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
goto x11_exit;
}
memcpy(channel->channel_type, "x11",
channel->channel_type_len + 1);
channel->remote.id = x11open_state->sender_channel;
channel->remote.window_size_initial =
LIBSSH2_CHANNEL_WINDOW_DEFAULT;
channel->remote.window_size = LIBSSH2_CHANNEL_WINDOW_DEFAULT;
channel->remote.packet_size = LIBSSH2_CHANNEL_PACKET_DEFAULT;
channel->local.id = _libssh2_channel_nextid(session);
channel->local.window_size_initial =
x11open_state->initial_window_size;
channel->local.window_size = x11open_state->initial_window_size;
channel->local.packet_size = x11open_state->packet_size;
_libssh2_debug(session, LIBSSH2_DBG_CONN,
"X11 Connection established: channel %lu/%lu win %lu/%lu packet %lu/%lu",
channel->local.id, channel->remote.id,
channel->local.window_size,
channel->remote.window_size,
channel->local.packet_size,
channel->remote.packet_size);
p = x11open_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_CONFIRMATION;
_libssh2_htonu32(p, channel->remote.id);
p += 4;
_libssh2_htonu32(p, channel->local.id);
p += 4;
_libssh2_htonu32(p, channel->remote.window_size_initial);
p += 4;
_libssh2_htonu32(p, channel->remote.packet_size);
p += 4;
x11open_state->state = libssh2_NB_state_created;
}
if (x11open_state->state == libssh2_NB_state_created) {
rc = _libssh2_transport_write(session, x11open_state->packet, 17);
if (rc == PACKET_EAGAIN) {
return PACKET_EAGAIN;
} else if (rc) {
libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send channel open confirmation", 0);
x11open_state->state = libssh2_NB_state_idle;
return -1;
}
/* Link the channel into the session */
if (session->channels.tail) {
session->channels.tail->next = channel;
channel->prev = session->channels.tail;
} else {
session->channels.head = channel;
channel->prev = NULL;
}
channel->next = NULL;
session->channels.tail = channel;
/*
* Pass control to the callback, they may turn right around and
* free the channel, or actually use it
*/
LIBSSH2_X11_OPEN(channel, (char *) x11open_state->shost,
x11open_state->sport);
x11open_state->state = libssh2_NB_state_idle;
return 0;
}
} else {
failure_code = 4; /* SSH_OPEN_RESOURCE_SHORTAGE */
}
x11_exit:
p = x11open_state->packet;
*(p++) = SSH_MSG_CHANNEL_OPEN_FAILURE;
_libssh2_htonu32(p, x11open_state->sender_channel);
p += 4;
_libssh2_htonu32(p, failure_code);
p += 4;
_libssh2_htonu32(p, sizeof(X11FwdUnAvil) - 1);
p += 4;
memcpy(s, X11FwdUnAvil, sizeof(X11FwdUnAvil) - 1);
p += sizeof(X11FwdUnAvil) - 1;
_libssh2_htonu32(p, 0);
rc = _libssh2_transport_write(session, x11open_state->packet, packet_len);
if (rc == PACKET_EAGAIN) {
return PACKET_EAGAIN;
} else if (rc) {
libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send open failure", 0);
x11open_state->state = libssh2_NB_state_idle;
return -1;
}
x11open_state->state = libssh2_NB_state_idle;
return 0;
}