commit d0cf5ae1f52fc3bf9daa4c3fb754cc77e4b74159 Author: Zack Weinberg zackw@panix.com Date: Sun Jul 24 18:32:18 2011 -0700

Break up the listener callback by listener mode, and delay creating the output buffer in socks mode till we know where to connect --- src/network.c | 227 +++++++++++++++++++++++++++++++++++++++++++-------------- src/network.h | 5 +- 2 files changed, 173 insertions(+), 59 deletions(-)

diff --git a/src/network.c b/src/network.c index 75d90ef..32d14ee 100644 --- a/src/network.c +++ b/src/network.c @@ -40,7 +40,11 @@ static smartlist_t *connections; connections and shutdowns when the last connection is closed. */ static int shutting_down=0;

-static void simple_listener_cb(struct evconnlistener *evcl, +static void simple_client_listener_cb(struct evconnlistener *evcl, + evutil_socket_t fd, struct sockaddr *sourceaddr, int socklen, void *arg); +static void socks_client_listener_cb(struct evconnlistener *evcl, + evutil_socket_t fd, struct sockaddr *sourceaddr, int socklen, void *arg); +static void simple_server_listener_cb(struct evconnlistener *evcl, evutil_socket_t fd, struct sockaddr *sourceaddr, int socklen, void *arg);

static void conn_free(conn_t *conn); @@ -108,23 +112,29 @@ close_all_connections(void) */ listener_t * listener_new(struct event_base *base, - protocol_params_t *proto_params) + protocol_params_t *params) { const unsigned flags = LEV_OPT_CLOSE_ON_FREE|LEV_OPT_CLOSE_ON_EXEC|LEV_OPT_REUSEABLE; - + evconnlistener_cb callback; listener_t *lsn = xzalloc(sizeof(listener_t));

- lsn->proto_params = proto_params; + switch (params->mode) { + case LSN_SIMPLE_CLIENT: callback = simple_client_listener_cb; break; + case LSN_SIMPLE_SERVER: callback = simple_server_listener_cb; break; + case LSN_SOCKS_CLIENT: callback = socks_client_listener_cb; break; + default: obfs_abort(); + }

+ lsn->proto_params = params; lsn->listener = - evconnlistener_new_bind(base, simple_listener_cb, lsn, flags, -1, - proto_params->listen_addr->ai_addr, - proto_params->listen_addr->ai_addrlen); + evconnlistener_new_bind(base, callback, lsn, flags, -1, + params->listen_addr->ai_addr, + params->listen_addr->ai_addrlen);

if (!lsn->listener) { log_warn("Failed to create listener!"); - proto_params_free(lsn->proto_params); + proto_params_free(params); free(lsn); return NULL; } @@ -167,23 +177,22 @@ free_all_listeners(void) }

/** - This function is called when a new connection is received. - - It initializes the protocol we are using, sets up the necessary - callbacks for input/output and does the protocol handshake. + This function is called when an upstream client connects to us in + simple client mode. */ static void -simple_listener_cb(struct evconnlistener *evcl, - evutil_socket_t fd, struct sockaddr *sourceaddr, - int socklen, void *arg) +simple_client_listener_cb(struct evconnlistener *evcl, + evutil_socket_t fd, struct sockaddr *sourceaddr, + int socklen, void *arg) { listener_t *lsn = arg; struct event_base *base; conn_t *conn = xzalloc(sizeof(conn_t));

- log_debug("Got a connection attempt."); + log_debug("%s: connection attempt.", __func__);

conn->mode = lsn->proto_params->mode; + obfs_assert(conn->mode == LSN_SIMPLE_CLIENT);

conn->proto = proto_create(lsn->proto_params); if (!conn->proto) { @@ -191,67 +200,161 @@ simple_listener_cb(struct evconnlistener *evcl, goto err; }

- if (conn->mode == LSN_SOCKS_CLIENT) { - /* Construct SOCKS state. */ - conn->socks_state = socks_state_new(); + /* New bufferevent to wrap socket we received. */ + base = evconnlistener_get_base(lsn->listener); + conn->input = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE); + if (!conn->input) + goto err; + fd = -1; /* prevent double-close */ + + /* New bufferevent to connect to the target address */ + conn->output = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE); + if (!conn->output) + goto err; + + bufferevent_setcb(conn->input, plaintext_read_cb, NULL, input_event_cb, conn); + bufferevent_enable(conn->input, EV_READ|EV_WRITE); + + bufferevent_setcb(conn->output, + obfuscated_read_cb, NULL, output_event_cb, conn); + + /* Queue output right now. */ + if (proto_handshake(conn->proto, bufferevent_get_output(conn->output)) < 0) + goto err; + + /* Launch the connect attempt. */ + if (bufferevent_socket_connect(conn->output, + lsn->proto_params->target_addr->ai_addr, + lsn->proto_params->target_addr->ai_addrlen)<0) + goto err; + + bufferevent_enable(conn->output, EV_READ|EV_WRITE); + + /* add conn to the connection list */ + if (!connections) + connections = smartlist_create(); + smartlist_add(connections, conn); + + log_debug("%s: setup completed, %d connections", + __func__, smartlist_len(connections)); + return; + + err: + if (conn) + conn_free(conn); + if (fd >= 0) + evutil_closesocket(fd); +} + +/** + This function is called when an upstream client connects to us in + socks mode. +*/ +static void +socks_client_listener_cb(struct evconnlistener *evcl, + evutil_socket_t fd, struct sockaddr *sourceaddr, + int socklen, void *arg) +{ + listener_t *lsn = arg; + struct event_base *base; + conn_t *conn = xzalloc(sizeof(conn_t)); + + log_debug("%s: connection attempt.", __func__); + + conn->mode = lsn->proto_params->mode; + obfs_assert(conn->mode == LSN_SOCKS_CLIENT); + + conn->proto = proto_create(lsn->proto_params); + if (!conn->proto) { + log_warn("Creation of protocol object failed! Closing connection."); + goto err; }

+ /* Construct SOCKS state. */ + conn->socks_state = socks_state_new(); + /* New bufferevent to wrap socket we received. */ base = evconnlistener_get_base(lsn->listener); - conn->input = bufferevent_socket_new(base, - fd, - BEV_OPT_CLOSE_ON_FREE); + conn->input = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE); if (!conn->input) goto err; fd = -1; /* prevent double-close */

- if (conn->mode == LSN_SIMPLE_SERVER) { - bufferevent_setcb(conn->input, - obfuscated_read_cb, NULL, input_event_cb, conn); - } else if (conn->mode == LSN_SIMPLE_CLIENT) { - bufferevent_setcb(conn->input, - plaintext_read_cb, NULL, input_event_cb, conn); - } else { - obfs_assert(conn->mode == LSN_SOCKS_CLIENT); - bufferevent_setcb(conn->input, - socks_read_cb, NULL, input_event_cb, conn); + bufferevent_setcb(conn->input, socks_read_cb, NULL, input_event_cb, conn); + bufferevent_enable(conn->input, EV_READ|EV_WRITE); + + /* Do not create a target bufferevent at this time; the socks + handler will do it after we know where we're connecting */ + + /* add conn to the connection list */ + if (!connections) + connections = smartlist_create(); + smartlist_add(connections, conn); + + log_debug("%s: setup completed, %d connections", + __func__, smartlist_len(connections)); + return; + + err: + if (conn) + conn_free(conn); + if (fd >= 0) + evutil_closesocket(fd); +} + +/** + This function is called when a remote client connects to us in + server mode. +*/ +static void +simple_server_listener_cb(struct evconnlistener *evcl, + evutil_socket_t fd, struct sockaddr *sourceaddr, + int socklen, void *arg) +{ + listener_t *lsn = arg; + struct event_base *base; + conn_t *conn = xzalloc(sizeof(conn_t)); + + log_debug("%s: connection attempt.", __func__); + + conn->mode = lsn->proto_params->mode; + obfs_assert(conn->mode == LSN_SIMPLE_SERVER); + + conn->proto = proto_create(lsn->proto_params); + if (!conn->proto) { + log_warn("Creation of protocol object failed! Closing connection."); + goto err; }

+ /* New bufferevent to wrap socket we received. */ + base = evconnlistener_get_base(lsn->listener); + conn->input = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE); + if (!conn->input) + goto err; + fd = -1; /* prevent double-close */ + + bufferevent_setcb(conn->input, obfuscated_read_cb, NULL, input_event_cb, conn); bufferevent_enable(conn->input, EV_READ|EV_WRITE);

/* New bufferevent to connect to the target address */ - conn->output = bufferevent_socket_new(base, - -1, - BEV_OPT_CLOSE_ON_FREE); + conn->output = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE); if (!conn->output) goto err;

- if (conn->mode == LSN_SIMPLE_SERVER) - bufferevent_setcb(conn->output, - plaintext_read_cb, NULL, output_event_cb, conn); - else - bufferevent_setcb(conn->output, - obfuscated_read_cb, NULL, output_event_cb, conn); - - /* Queue output right now. */ - struct bufferevent *encrypted = - conn->mode == LSN_SIMPLE_SERVER ? conn->input : conn->output; + bufferevent_setcb(conn->output, plaintext_read_cb, NULL, + output_event_cb, conn);

- /* ASN Will all protocols need to handshake here? Don't think so. */ + /* Queue handshake, if any, before connecting. */ if (proto_handshake(conn->proto, - bufferevent_get_output(encrypted))<0) + bufferevent_get_output(conn->input))<0) goto err;

- if (conn->mode == LSN_SIMPLE_SERVER || conn->mode == LSN_SIMPLE_CLIENT) { - /* Launch the connect attempt. */ - if (bufferevent_socket_connect(conn->output, - lsn->proto_params->target_addr->ai_addr, - lsn->proto_params->target_addr->ai_addrlen) - < 0) - goto err; + if (bufferevent_socket_connect(conn->output, + lsn->proto_params->target_addr->ai_addr, + lsn->proto_params->target_addr->ai_addrlen)<0) + goto err;

- bufferevent_enable(conn->output, EV_READ|EV_WRITE); - } + bufferevent_enable(conn->output, EV_READ|EV_WRITE);

/* add conn to the connection list */ if (!connections) @@ -346,6 +449,18 @@ socks_read_cb(struct bufferevent *bev, void *arg) const char *addr=NULL; r = socks_state_get_address(conn->socks_state, &af, &addr, &port); obfs_assert(r==0); + conn->output = bufferevent_socket_new(bufferevent_get_base(conn->input), + -1, + BEV_OPT_CLOSE_ON_FREE); + + /* queue handshake, if any, before connecting */ + if (proto_handshake(conn->proto, + bufferevent_get_output(conn->output))<0) { + /* XXXX send socks reply */ + close_conn(conn); + return; + } + r = bufferevent_socket_connect_hostname(conn->output, get_evdns_base(), af, addr, port); diff --git a/src/network.h b/src/network.h index 7ba9afc..49580c3 100644 --- a/src/network.h +++ b/src/network.h @@ -43,12 +43,11 @@ struct socks_state_t; struct protocol_t;

typedef struct conn_t { + struct protocol_t *proto; struct socks_state_t *socks_state; - struct protocol_t *proto; /* ASN Do we like this here? We probably don't. - But it's so convenient!! So convenient! */ - int mode; struct bufferevent *input; struct bufferevent *output; + unsigned int mode : 30; unsigned int flushing : 1; unsigned int is_open : 1; } conn_t;