src/transports/ssh.c - third_party/libgit2 - Git at Google

 /*
  * Copyright (C) the libgit2 contributors. All rights reserved.
  *
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */

 #ifdef GIT_SSH

 #include "git2.h"
 #include "buffer.h"
 #include "netops.h"
 #include "smart.h"

 #include <libssh2.h>

 #define OWNING_SUBTRANSPORT(s) ((ssh_subtransport *)(s)->parent.subtransport)

 static const char prefix_ssh[] = "ssh://";
 static const char default_user[] = "git";
 static const char cmd_uploadpack[] = "git-upload-pack";
 static const char cmd_receivepack[] = "git-receive-pack";

 typedef struct {
 	git_smart_subtransport_stream parent;
 	gitno_socket socket;
 	LIBSSH2_SESSION *session;
 	LIBSSH2_CHANNEL *channel;
 	const char *cmd;
 	char *url;
 	unsigned sent_command : 1;
 } ssh_stream;

 typedef struct {
 	git_smart_subtransport parent;
 	transport_smart *owner;
 	ssh_stream *current_stream;
 	git_cred *cred;
 } ssh_subtransport;

 /*
  * Create a git protocol request.
  *
  * For example: git-upload-pack '/libgit2/libgit2'
  */
 static int gen_proto(git_buf *request, const char *cmd, const char *url)
 {
 	char *repo;

 	if (!git__prefixcmp(url, prefix_ssh)) {
 		url = url + strlen(prefix_ssh);
 		repo = strchr(url, '/');
 	} else {
 		repo = strchr(url, ':');
 	}

 	if (!repo) {
 		return -1;
 	}

 	int len = strlen(cmd) + 1 /* Space */ + 1 /* Quote */ + strlen(repo) + 1 /* Quote */ + 1;

 	git_buf_grow(request, len);
 	git_buf_printf(request, "%s '%s'", cmd, repo);
 	git_buf_putc(request, '\0');

 	if (git_buf_oom(request))
 		return -1;

 	return 0;
 }

 static int send_command(ssh_stream *s)
 {
 	int error;
 	git_buf request = GIT_BUF_INIT;

 	error = gen_proto(&request, s->cmd, s->url);
 	if (error < 0)
 		goto cleanup;

 	error = libssh2_channel_exec(
 		s->channel,
 		request.ptr
 	);

 	if (0 != error)
 		goto cleanup;

 	s->sent_command = 1;

 cleanup:
 	git_buf_free(&request);
 	return error;
 }

 static int ssh_stream_read(
 	git_smart_subtransport_stream *stream,
 	char *buffer,
 	size_t buf_size,
 	size_t *bytes_read)
 {
 	ssh_stream *s = (ssh_stream *)stream;

 	*bytes_read = 0;

 	if (!s->sent_command && send_command(s) < 0)
 		return -1;

 	int rc = libssh2_channel_read(s->channel, buffer, buf_size);
 	if (rc < 0)
 		return -1;

 	*bytes_read = rc;

 	return 0;
 }

 static int ssh_stream_write(
 	git_smart_subtransport_stream *stream,
 	const char *buffer,
 	size_t len)
 {
 	ssh_stream *s = (ssh_stream *)stream;

 	if (!s->sent_command && send_command(s) < 0)
 		return -1;

 	int rc = libssh2_channel_write(s->channel, buffer, len);
 	if (rc < 0) {
 		return -1;
 	}

 	return rc;
 }

 static void ssh_stream_free(git_smart_subtransport_stream *stream)
 {
 	ssh_stream *s = (ssh_stream *)stream;
 	ssh_subtransport *t = OWNING_SUBTRANSPORT(s);
 	int ret;

 	GIT_UNUSED(ret);

 	t->current_stream = NULL;

 	if (s->channel) {
 		libssh2_channel_close(s->channel);
         libssh2_channel_free(s->channel);
         s->channel = NULL;
 	}

 	if (s->session) {
 		libssh2_session_free(s->session), s->session = NULL;
 	}

 	if (s->socket.socket) {
 		ret = gitno_close(&s->socket);
 		assert(!ret);
 	}

 	git__free(s->url);
 	git__free(s);
 }

 static int ssh_stream_alloc(
 	ssh_subtransport *t,
 	const char *url,
 	const char *cmd,
 	git_smart_subtransport_stream **stream)
 {
 	ssh_stream *s;

 	if (!stream)
 		return -1;

 	s = git__calloc(sizeof(ssh_stream), 1);
 	GITERR_CHECK_ALLOC(s);

 	s->parent.subtransport = &t->parent;
 	s->parent.read = ssh_stream_read;
 	s->parent.write = ssh_stream_write;
 	s->parent.free = ssh_stream_free;

 	s->cmd = cmd;
 	s->url = git__strdup(url);

 	if (!s->url) {
 		git__free(s);
 		return -1;
 	}

 	*stream = &s->parent;
 	return 0;
 }

 static int git_ssh_extract_url_parts(
 	char **host,
 	char **username,
 	const char *url)
 {
 	char *colon, *at;
 	const char *start;

     colon = strchr(url, ':');

 	if (colon == NULL) {
 		giterr_set(GITERR_NET, "Malformed URL: missing :");
 		return -1;
 	}

 	at = strchr(url, '@');
 	if (at) {
 		start = at+1;
 		*username = git__substrdup(url, at - url);
 	} else {
 		start = url;
 		*username = git__strdup(default_user);
 	}

 	*host = git__substrdup(start, colon - start);

 	return 0;
 }

 static int _git_ssh_authenticate_session(
 	LIBSSH2_SESSION* session,
 	const char *user,
 	git_cred* cred
 )
 {
 	int rc;
 	do {
 		switch (cred->credtype) {
 			case GIT_CREDTYPE_USERPASS_PLAINTEXT: {
 				git_cred_userpass_plaintext *c = (git_cred_userpass_plaintext *)cred;
 				rc = libssh2_userauth_password(
 					session,
 					c->username,
 					c->password
 				);
 				break;
 			}
 			case GIT_CREDTYPE_SSH_KEYFILE_PASSPHRASE: {
 				git_cred_ssh_keyfile_passphrase *c = (git_cred_ssh_keyfile_passphrase *)cred;
 				rc = libssh2_userauth_publickey_fromfile(
 					session,
 					user,
 					c->publickey,
 					c->privatekey,
 					c->passphrase
 				);
 				break;
 			}
 			case GIT_CREDTYPE_SSH_PUBLICKEY: {
 				git_cred_ssh_publickey *c = (git_cred_ssh_publickey *)cred;
 				rc = libssh2_userauth_publickey(
 					session,
 					user,
 					(const unsigned char *)c->publickey,
 					c->publickey_len,
 					c->sign_callback,
 					&c->sign_data
 				);
 				break;
 			}
 			default:
 				rc = LIBSSH2_ERROR_AUTHENTICATION_FAILED;
 		}
     } while (LIBSSH2_ERROR_EAGAIN == rc || LIBSSH2_ERROR_TIMEOUT == rc);

     return rc;
 }

 static int _git_ssh_session_create
 (
 	LIBSSH2_SESSION** session,
 	gitno_socket socket
 )
 {
 	if (!session) {
 		return -1;
 	}

 	LIBSSH2_SESSION* s = libssh2_session_init();
     if (!s)
         return -1;

     int rc = 0;
     do {
         rc = libssh2_session_startup(s, socket.socket);
     } while (LIBSSH2_ERROR_EAGAIN == rc || LIBSSH2_ERROR_TIMEOUT == rc);

 	if (0 != rc) {
         goto on_error;
     }

 	libssh2_session_set_blocking(s, 1);

 	*session = s;

 	return 0;

 on_error:
 	if (s) {
 		libssh2_session_free(s), s = NULL;
 	}

 	return -1;
 }

 static int _git_ssh_setup_conn(
 	ssh_subtransport *t,
 	const char *url,
 	const char *cmd,
 	git_smart_subtransport_stream **stream
 )
 {
 	char *host, *port=NULL, *user=NULL, *pass=NULL;
 	const char *default_port="22";
 	ssh_stream *s;
 	LIBSSH2_SESSION* session=NULL;
 	LIBSSH2_CHANNEL* channel=NULL;

 	*stream = NULL;
 	if (ssh_stream_alloc(t, url, cmd, stream) < 0)
 		return -1;

 	s = (ssh_stream *)*stream;

 	if (!git__prefixcmp(url, prefix_ssh)) {
 		url = url + strlen(prefix_ssh);
 		if (gitno_extract_url_parts(&host, &port, &user, &pass, url, default_port) < 0)
 			goto on_error;
 	} else {
 		if (git_ssh_extract_url_parts(&host, &user, url) < 0)
 			goto on_error;
 		port = git__strdup(default_port);
 		GITERR_CHECK_ALLOC(port);
 	}

 	if (gitno_connect(&s->socket, host, port, 0) < 0)
 		goto on_error;

 	if (user && pass) {
 		if (git_cred_userpass_plaintext_new(&t->cred, user, pass) < 0)
 			goto on_error;
 	} else {
 		if (t->owner->cred_acquire_cb(&t->cred,
 				t->owner->url,
 				user,
 				GIT_CREDTYPE_USERPASS_PLAINTEXT | GIT_CREDTYPE_SSH_KEYFILE_PASSPHRASE,
 				t->owner->cred_acquire_payload) < 0)
 			return -1;
 	}
 	assert(t->cred);

 	if (!user) {
 		user = git__strdup(default_user);
 	}

 	if (_git_ssh_session_create(&session, s->socket) < 0)
 		goto on_error;

     if (_git_ssh_authenticate_session(session, user, t->cred) < 0)
 		goto on_error;

 	channel = libssh2_channel_open_session(session);
 	if (!channel)
         goto on_error;

 	libssh2_channel_set_blocking(channel, 1);

 	s->session = session;
 	s->channel = channel;

 	t->current_stream = s;
 	git__free(host);
 	git__free(port);
 	git__free(user);
 	git__free(pass);

 	return 0;

 on_error:
 	if (*stream)
 		ssh_stream_free(*stream);

 	git__free(host);
 	git__free(port);
 	git__free(user);
 	git__free(pass);

 	if (session)
 		libssh2_session_free(session), session = NULL;

 	return -1;
 }

 static int ssh_uploadpack_ls(
 	ssh_subtransport *t,
 	const char *url,
 	git_smart_subtransport_stream **stream)
 {
 	if (_git_ssh_setup_conn(t, url, cmd_uploadpack, stream) < 0)
 		return -1;

 	return 0;
 }

 static int ssh_uploadpack(
 	ssh_subtransport *t,
 	const char *url,
 	git_smart_subtransport_stream **stream)
 {
 	GIT_UNUSED(url);

 	if (t->current_stream) {
 		*stream = &t->current_stream->parent;
 		return 0;
 	}

 	giterr_set(GITERR_NET, "Must call UPLOADPACK_LS before UPLOADPACK");
 	return -1;
 }

 static int ssh_receivepack_ls(
 	ssh_subtransport *t,
 	const char *url,
 	git_smart_subtransport_stream **stream)
 {
 	if (_git_ssh_setup_conn(t, url, cmd_receivepack, stream) < 0)
 		return -1;

 	return 0;
 }

 static int ssh_receivepack(
 	ssh_subtransport *t,
 	const char *url,
 	git_smart_subtransport_stream **stream)
 {
 	GIT_UNUSED(url);

 	if (t->current_stream) {
 		*stream = &t->current_stream->parent;
 		return 0;
 	}

 	giterr_set(GITERR_NET, "Must call RECEIVEPACK_LS before RECEIVEPACK");
 	return -1;
 }

 static int _ssh_action(
 	git_smart_subtransport_stream **stream,
 	git_smart_subtransport *subtransport,
 	const char *url,
 	git_smart_service_t action)
 {
 	ssh_subtransport *t = (ssh_subtransport *) subtransport;

 	switch (action) {
 		case GIT_SERVICE_UPLOADPACK_LS:
 			return ssh_uploadpack_ls(t, url, stream);

 		case GIT_SERVICE_UPLOADPACK:
 			return ssh_uploadpack(t, url, stream);

 		case GIT_SERVICE_RECEIVEPACK_LS:
 			return ssh_receivepack_ls(t, url, stream);

 		case GIT_SERVICE_RECEIVEPACK:
 			return ssh_receivepack(t, url, stream);
 	}

 	*stream = NULL;
 	return -1;
 }

 static int _ssh_close(git_smart_subtransport *subtransport)
 {
 	ssh_subtransport *t = (ssh_subtransport *) subtransport;

 	assert(!t->current_stream);

 	GIT_UNUSED(t);

 	return 0;
 }

 static void _ssh_free(git_smart_subtransport *subtransport)
 {
 	ssh_subtransport *t = (ssh_subtransport *) subtransport;

 	assert(!t->current_stream);

 	git__free(t);
 }

 int git_smart_subtransport_ssh(git_smart_subtransport **out, git_transport *owner)
 {
 	ssh_subtransport *t;

 	if (!out)
 		return -1;

 	t = git__calloc(sizeof(ssh_subtransport), 1);
 	GITERR_CHECK_ALLOC(t);

 	t->owner = (transport_smart *)owner;
 	t->parent.action = _ssh_action;
 	t->parent.close = _ssh_close;
 	t->parent.free = _ssh_free;

 	*out = (git_smart_subtransport *) t;
 	return 0;
 }

 #endif
	/*
	* Copyright (C) the libgit2 contributors. All rights reserved.
	*
	* This file is part of libgit2, distributed under the GNU GPL v2 with
	* a Linking Exception. For full terms see the included COPYING file.
	*/

	#ifdef GIT_SSH

	#include "git2.h"
	#include "buffer.h"
	#include "netops.h"
	#include "smart.h"

	#include <libssh2.h>

	#define OWNING_SUBTRANSPORT(s) ((ssh_subtransport *)(s)->parent.subtransport)

	static const char prefix_ssh[] = "ssh://";
	static const char default_user[] = "git";
	static const char cmd_uploadpack[] = "git-upload-pack";
	static const char cmd_receivepack[] = "git-receive-pack";

	typedef struct {
	git_smart_subtransport_stream parent;
	gitno_socket socket;
	LIBSSH2_SESSION *session;
	LIBSSH2_CHANNEL *channel;
	const char *cmd;
	char *url;
	unsigned sent_command : 1;
	} ssh_stream;

	typedef struct {
	git_smart_subtransport parent;
	transport_smart *owner;
	ssh_stream *current_stream;
	git_cred *cred;
	} ssh_subtransport;

	/*
	* Create a git protocol request.
	*
	* For example: git-upload-pack '/libgit2/libgit2'
	*/
	static int gen_proto(git_buf request, const char cmd, const char *url)
	{
	char *repo;

	if (!git__prefixcmp(url, prefix_ssh)) {
	url = url + strlen(prefix_ssh);
	repo = strchr(url, '/');
	} else {
	repo = strchr(url, ':');
	}

	if (!repo) {
	return -1;
	}

	int len = strlen(cmd) + 1 /* Space / + 1 / Quote / + strlen(repo) + 1 / Quote */ + 1;

	git_buf_grow(request, len);
	git_buf_printf(request, "%s '%s'", cmd, repo);
	git_buf_putc(request, '\0');

	if (git_buf_oom(request))
	return -1;

	return 0;
	}

	static int send_command(ssh_stream *s)
	{
	int error;
	git_buf request = GIT_BUF_INIT;

	error = gen_proto(&request, s->cmd, s->url);
	if (error < 0)
	goto cleanup;

	error = libssh2_channel_exec(
	s->channel,
	request.ptr
	);

	if (0 != error)
	goto cleanup;

	s->sent_command = 1;

	cleanup:
	git_buf_free(&request);
	return error;
	}

	static int ssh_stream_read(
	git_smart_subtransport_stream *stream,
	char *buffer,
	size_t buf_size,
	size_t *bytes_read)
	{
	ssh_stream s = (ssh_stream )stream;

	*bytes_read = 0;

	if (!s->sent_command && send_command(s) < 0)
	return -1;

	int rc = libssh2_channel_read(s->channel, buffer, buf_size);
	if (rc < 0)
	return -1;

	*bytes_read = rc;

	return 0;
	}

	static int ssh_stream_write(
	git_smart_subtransport_stream *stream,
	const char *buffer,
	size_t len)
	{
	ssh_stream s = (ssh_stream )stream;

	if (!s->sent_command && send_command(s) < 0)
	return -1;

	int rc = libssh2_channel_write(s->channel, buffer, len);
	if (rc < 0) {
	return -1;
	}

	return rc;
	}

	static void ssh_stream_free(git_smart_subtransport_stream *stream)
	{
	ssh_stream s = (ssh_stream )stream;
	ssh_subtransport *t = OWNING_SUBTRANSPORT(s);
	int ret;

	GIT_UNUSED(ret);

	t->current_stream = NULL;

	if (s->channel) {
	libssh2_channel_close(s->channel);
	libssh2_channel_free(s->channel);
	s->channel = NULL;
	}

	if (s->session) {
	libssh2_session_free(s->session), s->session = NULL;
	}

	if (s->socket.socket) {
	ret = gitno_close(&s->socket);
	assert(!ret);
	}

	git__free(s->url);
	git__free(s);
	}

	static int ssh_stream_alloc(
	ssh_subtransport *t,
	const char *url,
	const char *cmd,
	git_smart_subtransport_stream **stream)
	{
	ssh_stream *s;

	if (!stream)
	return -1;

	s = git__calloc(sizeof(ssh_stream), 1);
	GITERR_CHECK_ALLOC(s);

	s->parent.subtransport = &t->parent;
	s->parent.read = ssh_stream_read;
	s->parent.write = ssh_stream_write;
	s->parent.free = ssh_stream_free;

	s->cmd = cmd;
	s->url = git__strdup(url);

	if (!s->url) {
	git__free(s);
	return -1;
	}

	*stream = &s->parent;
	return 0;
	}

	static int git_ssh_extract_url_parts(
	char **host,
	char **username,
	const char *url)
	{
	char colon, at;
	const char *start;

	colon = strchr(url, ':');

	if (colon == NULL) {
	giterr_set(GITERR_NET, "Malformed URL: missing :");
	return -1;
	}

	at = strchr(url, '@');
	if (at) {
	start = at+1;
	*username = git__substrdup(url, at - url);
	} else {
	start = url;
	*username = git__strdup(default_user);
	}

	*host = git__substrdup(start, colon - start);

	return 0;
	}

	static int _git_ssh_authenticate_session(
	LIBSSH2_SESSION* session,
	const char *user,
	git_cred* cred
	)
	{
	int rc;
	do {
	switch (cred->credtype) {
	case GIT_CREDTYPE_USERPASS_PLAINTEXT: {
	git_cred_userpass_plaintext c = (git_cred_userpass_plaintext )cred;
	rc = libssh2_userauth_password(
	session,
	c->username,
	c->password
	);
	break;
	}
	case GIT_CREDTYPE_SSH_KEYFILE_PASSPHRASE: {
	git_cred_ssh_keyfile_passphrase c = (git_cred_ssh_keyfile_passphrase )cred;
	rc = libssh2_userauth_publickey_fromfile(
	session,
	user,
	c->publickey,
	c->privatekey,
	c->passphrase
	);
	break;
	}
	case GIT_CREDTYPE_SSH_PUBLICKEY: {
	git_cred_ssh_publickey c = (git_cred_ssh_publickey )cred;
	rc = libssh2_userauth_publickey(
	session,
	user,
	(const unsigned char *)c->publickey,
	c->publickey_len,
	c->sign_callback,
	&c->sign_data
	);
	break;
	}
	default:
	rc = LIBSSH2_ERROR_AUTHENTICATION_FAILED;
	}
	} while (LIBSSH2_ERROR_EAGAIN == rc \|\| LIBSSH2_ERROR_TIMEOUT == rc);

	return rc;
	}

	static int _git_ssh_session_create
	(
	LIBSSH2_SESSION** session,
	gitno_socket socket
	)
	{
	if (!session) {
	return -1;
	}

	LIBSSH2_SESSION* s = libssh2_session_init();
	if (!s)
	return -1;

	int rc = 0;
	do {
	rc = libssh2_session_startup(s, socket.socket);
	} while (LIBSSH2_ERROR_EAGAIN == rc \|\| LIBSSH2_ERROR_TIMEOUT == rc);

	if (0 != rc) {
	goto on_error;
	}

	libssh2_session_set_blocking(s, 1);

	*session = s;

	return 0;

	on_error:
	if (s) {
	libssh2_session_free(s), s = NULL;
	}

	return -1;
	}

	static int _git_ssh_setup_conn(
	ssh_subtransport *t,
	const char *url,
	const char *cmd,
	git_smart_subtransport_stream **stream
	)
	{
	char host, port=NULL, user=NULL, pass=NULL;
	const char *default_port="22";
	ssh_stream *s;
	LIBSSH2_SESSION* session=NULL;
	LIBSSH2_CHANNEL* channel=NULL;

	*stream = NULL;
	if (ssh_stream_alloc(t, url, cmd, stream) < 0)
	return -1;

	s = (ssh_stream )stream;

	if (!git__prefixcmp(url, prefix_ssh)) {
	url = url + strlen(prefix_ssh);
	if (gitno_extract_url_parts(&host, &port, &user, &pass, url, default_port) < 0)
	goto on_error;
	} else {
	if (git_ssh_extract_url_parts(&host, &user, url) < 0)
	goto on_error;
	port = git__strdup(default_port);
	GITERR_CHECK_ALLOC(port);
	}

	if (gitno_connect(&s->socket, host, port, 0) < 0)
	goto on_error;

	if (user && pass) {
	if (git_cred_userpass_plaintext_new(&t->cred, user, pass) < 0)
	goto on_error;
	} else {
	if (t->owner->cred_acquire_cb(&t->cred,
	t->owner->url,
	user,
	GIT_CREDTYPE_USERPASS_PLAINTEXT \| GIT_CREDTYPE_SSH_KEYFILE_PASSPHRASE,
	t->owner->cred_acquire_payload) < 0)
	return -1;
	}
	assert(t->cred);

	if (!user) {
	user = git__strdup(default_user);
	}

	if (_git_ssh_session_create(&session, s->socket) < 0)
	goto on_error;

	if (_git_ssh_authenticate_session(session, user, t->cred) < 0)
	goto on_error;

	channel = libssh2_channel_open_session(session);
	if (!channel)
	goto on_error;

	libssh2_channel_set_blocking(channel, 1);

	s->session = session;
	s->channel = channel;

	t->current_stream = s;
	git__free(host);
	git__free(port);
	git__free(user);
	git__free(pass);

	return 0;

	on_error:
	if (*stream)
	ssh_stream_free(*stream);

	git__free(host);
	git__free(port);
	git__free(user);
	git__free(pass);

	if (session)
	libssh2_session_free(session), session = NULL;

	return -1;
	}

	static int ssh_uploadpack_ls(
	ssh_subtransport *t,
	const char *url,
	git_smart_subtransport_stream **stream)
	{
	if (_git_ssh_setup_conn(t, url, cmd_uploadpack, stream) < 0)
	return -1;

	return 0;
	}

	static int ssh_uploadpack(
	ssh_subtransport *t,
	const char *url,
	git_smart_subtransport_stream **stream)
	{
	GIT_UNUSED(url);

	if (t->current_stream) {
	*stream = &t->current_stream->parent;
	return 0;
	}

	giterr_set(GITERR_NET, "Must call UPLOADPACK_LS before UPLOADPACK");
	return -1;
	}

	static int ssh_receivepack_ls(
	ssh_subtransport *t,
	const char *url,
	git_smart_subtransport_stream **stream)
	{
	if (_git_ssh_setup_conn(t, url, cmd_receivepack, stream) < 0)
	return -1;

	return 0;
	}

	static int ssh_receivepack(
	ssh_subtransport *t,
	const char *url,
	git_smart_subtransport_stream **stream)
	{
	GIT_UNUSED(url);

	if (t->current_stream) {
	*stream = &t->current_stream->parent;
	return 0;
	}

	giterr_set(GITERR_NET, "Must call RECEIVEPACK_LS before RECEIVEPACK");
	return -1;
	}

	static int _ssh_action(
	git_smart_subtransport_stream **stream,
	git_smart_subtransport *subtransport,
	const char *url,
	git_smart_service_t action)
	{
	ssh_subtransport t = (ssh_subtransport ) subtransport;

	switch (action) {
	case GIT_SERVICE_UPLOADPACK_LS:
	return ssh_uploadpack_ls(t, url, stream);

	case GIT_SERVICE_UPLOADPACK:
	return ssh_uploadpack(t, url, stream);

	case GIT_SERVICE_RECEIVEPACK_LS:
	return ssh_receivepack_ls(t, url, stream);

	case GIT_SERVICE_RECEIVEPACK:
	return ssh_receivepack(t, url, stream);
	}

	*stream = NULL;
	return -1;
	}

	static int _ssh_close(git_smart_subtransport *subtransport)
	{
	ssh_subtransport t = (ssh_subtransport ) subtransport;

	assert(!t->current_stream);

	GIT_UNUSED(t);

	return 0;
	}

	static void _ssh_free(git_smart_subtransport *subtransport)
	{
	ssh_subtransport t = (ssh_subtransport ) subtransport;

	assert(!t->current_stream);

	git__free(t);
	}

	int git_smart_subtransport_ssh(git_smart_subtransport *out, git_transport owner)
	{
	ssh_subtransport *t;

	if (!out)
	return -1;

	t = git__calloc(sizeof(ssh_subtransport), 1);
	GITERR_CHECK_ALLOC(t);

	t->owner = (transport_smart *)owner;
	t->parent.action = _ssh_action;
	t->parent.close = _ssh_close;
	t->parent.free = _ssh_free;

	out = (git_smart_subtransport ) t;
	return 0;
	}

	#endif