tor/src/or/connection_edge.c

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/* Copyright 2001,2002 Roger Dingledine, Matej Pfajfar. */
/* See LICENSE for licensing information */
/* $Id$ */
#include "or.h"
extern or_options_t options; /* command-line and config-file options */
static int connection_ap_handshake_process_socks(connection_t *conn);
static int connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t *circ,
char *destaddr, uint16_t destport);
static int connection_ap_handshake_socks_reply(connection_t *conn, char result);
static int connection_exit_begin_conn(cell_t *cell, circuit_t *circ);
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#define SOCKS4_REQUEST_GRANTED 90
#define SOCKS4_REQUEST_REJECT 91
#define SOCKS4_REQUEST_IDENT_FAILED 92
#define SOCKS4_REQUEST_IDENT_CONFLICT 93
int connection_edge_process_inbuf(connection_t *conn) {
assert(conn);
assert(conn->type == CONN_TYPE_AP || conn->type == CONN_TYPE_EXIT);
if(conn->inbuf_reached_eof) {
#ifdef HALF_OPEN
/* eof reached; we're done reading, but we might want to write more. */
conn->done_receiving = 1;
shutdown(conn->s, 0); /* XXX check return, refactor NM */
if (conn->done_sending)
conn->marked_for_close = 1;
/* XXX Factor out common logic here and in circuit_about_to_close NM */
circ = circuit_get_by_conn(conn);
if (!circ)
return -1;
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
cell.length = RELAY_HEADER_SIZE;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_END);
SET_CELL_STREAM_ID(cell, conn->stream_id);
cell.aci = circ->n_aci;
if (circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION(conn->type), conn->cpath_layer) < 0) {
log(LOG_DEBUG,"circuit_deliver_relay_cell failed. Closing.");
circuit_close(circ);
}
return 0;
#else
/* eof reached, kill it. */
log_fn(LOG_DEBUG,"conn reached eof. Closing.");
return -1;
#endif
}
switch(conn->state) {
case AP_CONN_STATE_SOCKS_WAIT:
return connection_ap_handshake_process_socks(conn);
case AP_CONN_STATE_OPEN:
case EXIT_CONN_STATE_OPEN:
if(connection_package_raw_inbuf(conn) < 0)
return -1;
return 0;
case EXIT_CONN_STATE_CONNECTING:
log_fn(LOG_DEBUG,"text from server while in 'connecting' state at exit. Leaving it on buffer.");
return 0;
}
return 0;
}
int connection_edge_send_command(connection_t *fromconn, circuit_t *circ, int relay_command) {
cell_t cell;
int cell_direction;
if(!circ) {
log_fn(LOG_DEBUG,"no circ. Closing.");
return -1;
}
memset(&cell, 0, sizeof(cell_t));
if(fromconn && fromconn->type == CONN_TYPE_AP) {
cell.aci = circ->n_aci;
cell_direction = CELL_DIRECTION_OUT;
} else {
/* NOTE: if !fromconn, we assume that it's heading towards the OP */
cell.aci = circ->p_aci;
cell_direction = CELL_DIRECTION_IN;
}
cell.command = CELL_RELAY;
SET_CELL_RELAY_COMMAND(cell, relay_command);
if(fromconn)
SET_CELL_STREAM_ID(cell, fromconn->stream_id);
else
SET_CELL_STREAM_ID(cell, ZERO_STREAM);
cell.length = RELAY_HEADER_SIZE;
log_fn(LOG_INFO,"delivering %d cell %s.", relay_command, cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward");
if(circuit_deliver_relay_cell(&cell, circ, cell_direction, fromconn ? fromconn->cpath_layer : NULL) < 0) {
log_fn(LOG_DEBUG,"circuit_deliver_relay_cell failed. Closing.");
circuit_close(circ);
return 0;
}
return 0;
}
/* an incoming relay cell has arrived. return -1 if you want to tear down the
* circuit, else 0. */
int connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, connection_t *conn,
int edge_type, crypt_path_t *layer_hint) {
int relay_command;
static int num_seen=0;
assert(cell && circ);
relay_command = CELL_RELAY_COMMAND(*cell);
// log_fn(LOG_DEBUG,"command %d stream %d", relay_command, stream_id);
num_seen++;
log_fn(LOG_DEBUG,"Now seen %d relay cells here.", num_seen);
/* either conn is NULL, in which case we've got a control cell, or else
* conn points to the recognized stream. */
if(conn && conn->state != AP_CONN_STATE_OPEN && conn->state != EXIT_CONN_STATE_OPEN) {
if(conn->type == CONN_TYPE_EXIT && relay_command == RELAY_COMMAND_END) {
log_fn(LOG_INFO,"Exit got end before we're connected. Marking for close.");
conn->marked_for_close = 1;
if(conn->state == EXIT_CONN_STATE_RESOLVING) {
log_fn(LOG_INFO,"...and informing resolver we don't want the answer anymore.");
dns_cancel_pending_resolve(conn->address, conn);
}
} else {
log_fn(LOG_DEBUG,"Got an unexpected relay cell, not in 'open' state. Dropping.");
}
return 0;
}
switch(relay_command) {
case RELAY_COMMAND_BEGIN:
if(edge_type == EDGE_AP) {
log_fn(LOG_INFO,"relay begin request unsupported. Dropping.");
return 0;
}
if(conn) {
log_fn(LOG_INFO,"begin cell for known stream. Dropping.");
return 0;
}
return connection_exit_begin_conn(cell, circ);
case RELAY_COMMAND_DATA:
if((edge_type == EDGE_AP && --layer_hint->deliver_window < 0) ||
(edge_type == EDGE_EXIT && --circ->deliver_window < 0)) {
log_fn(LOG_DEBUG,"circ deliver_window below 0. Killing.");
return -1;
}
log_fn(LOG_DEBUG,"circ deliver_window now %d.", edge_type == EDGE_AP ? layer_hint->deliver_window : circ->deliver_window);
if(circuit_consider_sending_sendme(circ, edge_type, layer_hint) < 0)
return -1;
if(!conn) {
log_fn(LOG_DEBUG,"relay cell dropped, unknown stream %d.",*(int*)conn->stream_id);
return 0;
}
if(--conn->deliver_window < 0) { /* is it below 0 after decrement? */
log_fn(LOG_DEBUG,"conn deliver_window below 0. Killing.");
return -1; /* somebody's breaking protocol. kill the whole circuit. */
}
// printf("New text for buf (%d bytes): '%s'", cell->length - RELAY_HEADER_SIZE, cell->payload + RELAY_HEADER_SIZE);
if(connection_write_to_buf(cell->payload + RELAY_HEADER_SIZE,
cell->length - RELAY_HEADER_SIZE, conn) < 0) {
conn->marked_for_close = 1;
return 0;
}
if(connection_consider_sending_sendme(conn, edge_type) < 0)
conn->marked_for_close = 1;
return 0;
case RELAY_COMMAND_END:
if(!conn) {
log_fn(LOG_DEBUG,"end cell dropped, unknown stream %d.",*(int*)conn->stream_id);
return 0;
}
log_fn(LOG_DEBUG,"end cell for stream %d. Removing stream.",*(int*)conn->stream_id);
#ifdef HALF_OPEN
conn->done_sending = 1;
shutdown(conn->s, 1); /* XXX check return; refactor NM */
if (conn->done_receiving)
conn->marked_for_close = 1;
#endif
conn->marked_for_close = 1;
break;
case RELAY_COMMAND_EXTEND:
if(conn) {
log_fn(LOG_INFO,"'extend' for non-zero stream. Dropping.");
return 0;
}
return circuit_extend(cell, circ);
case RELAY_COMMAND_EXTENDED:
if(edge_type == EDGE_EXIT) {
log_fn(LOG_INFO,"'extended' unsupported at exit. Dropping.");
return 0;
}
log_fn(LOG_DEBUG,"Got an extended cell! Yay.");
if(circuit_finish_handshake(circ, cell->payload+RELAY_HEADER_SIZE) < 0) {
log_fn(LOG_INFO,"circuit_finish_handshake failed.");
return -1;
}
return circuit_send_next_onion_skin(circ);
case RELAY_COMMAND_TRUNCATE:
if(edge_type == EDGE_AP) {
log_fn(LOG_INFO,"'truncate' unsupported at AP. Dropping.");
return 0;
}
if(circ->n_conn) {
connection_send_destroy(circ->n_aci, circ->n_conn);
circ->n_conn = NULL;
}
log_fn(LOG_DEBUG, "Processed 'truncate', replying.");
return connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED);
case RELAY_COMMAND_TRUNCATED:
if(edge_type == EDGE_EXIT) {
log_fn(LOG_INFO,"'truncated' unsupported at exit. Dropping.");
return 0;
}
return circuit_truncated(circ, layer_hint);
case RELAY_COMMAND_CONNECTED:
if(edge_type == EDGE_EXIT) {
log_fn(LOG_INFO,"'connected' unsupported at exit. Dropping.");
return 0;
}
if(!conn) {
log_fn(LOG_DEBUG,"connected cell dropped, unknown stream %d.",*(int*)conn->stream_id);
break;
}
log_fn(LOG_DEBUG,"Connected! Notifying application.");
if(connection_ap_handshake_socks_reply(conn, SOCKS4_REQUEST_GRANTED) < 0) {
conn->marked_for_close = 1;
}
break;
case RELAY_COMMAND_SENDME:
if(!conn) {
if(edge_type == EDGE_AP) {
assert(layer_hint);
layer_hint->package_window += CIRCWINDOW_INCREMENT;
log_fn(LOG_DEBUG,"circ-level sendme at AP, packagewindow %d.", layer_hint->package_window);
circuit_resume_edge_reading(circ, EDGE_AP, layer_hint);
} else {
assert(!layer_hint);
circ->package_window += CIRCWINDOW_INCREMENT;
log_fn(LOG_DEBUG,"circ-level sendme at exit, packagewindow %d.", circ->package_window);
circuit_resume_edge_reading(circ, EDGE_EXIT, layer_hint);
}
return 0;
}
conn->package_window += STREAMWINDOW_INCREMENT;
log_fn(LOG_DEBUG,"stream-level sendme, packagewindow now %d.", conn->package_window);
connection_start_reading(conn);
connection_package_raw_inbuf(conn); /* handle whatever might still be on the inbuf */
break;
default:
log_fn(LOG_DEBUG,"unknown relay command %d.",relay_command);
}
return 0;
}
int connection_edge_finished_flushing(connection_t *conn) {
int e, len=sizeof(e);
assert(conn);
assert(conn->type == CONN_TYPE_AP || conn->type == CONN_TYPE_EXIT);
switch(conn->state) {
case EXIT_CONN_STATE_CONNECTING:
if (getsockopt(conn->s, SOL_SOCKET, SO_ERROR, (void*)&e, &len) < 0) { /* not yet */
if(!ERRNO_CONN_EINPROGRESS(errno)) {
/* yuck. kill it. */
log_fn(LOG_DEBUG,"in-progress exit connect failed. Removing.");
return -1;
} else {
log_fn(LOG_DEBUG,"in-progress exit connect still waiting.");
return 0; /* no change, see if next time is better */
}
}
/* the connect has finished. */
log_fn(LOG_DEBUG,"Exit connection to %s:%u established.",
conn->address,conn->port);
conn->state = EXIT_CONN_STATE_OPEN;
connection_watch_events(conn, POLLIN); /* stop writing, continue reading */
if(connection_wants_to_flush(conn)) /* in case there are any queued relay cells */
connection_start_writing(conn);
return
connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_CONNECTED) || /* deliver a 'connected' relay cell back through the circuit. */
connection_process_inbuf(conn); /* in case the server has written anything */
case AP_CONN_STATE_OPEN:
case EXIT_CONN_STATE_OPEN:
connection_stop_writing(conn);
return connection_consider_sending_sendme(conn, conn->type);
default:
log_fn(LOG_DEBUG,"BUG: called in unexpected state.");
return 0;
}
return 0;
}
int connection_package_raw_inbuf(connection_t *conn) {
int amount_to_process;
cell_t cell;
circuit_t *circ;
assert(conn);
assert(!connection_speaks_cells(conn));
repeat_connection_package_raw_inbuf:
circ = circuit_get_by_conn(conn);
if(!circ) {
log_fn(LOG_DEBUG,"conn has no circuits!");
return -1;
}
if(circuit_consider_stop_edge_reading(circ, conn->type, conn->cpath_layer))
return 0;
if(conn->package_window <= 0) {
log_fn(LOG_ERR,"called with package_window 0. Tell Roger.");
connection_stop_reading(conn);
return 0;
}
amount_to_process = conn->inbuf_datalen;
if(!amount_to_process)
return 0;
/* Initialize the cell with 0's */
memset(&cell, 0, sizeof(cell_t));
if(amount_to_process > CELL_PAYLOAD_SIZE - RELAY_HEADER_SIZE) {
cell.length = CELL_PAYLOAD_SIZE - RELAY_HEADER_SIZE;
} else {
cell.length = amount_to_process;
}
connection_fetch_from_buf(cell.payload+RELAY_HEADER_SIZE, cell.length, conn);
log_fn(LOG_DEBUG,"(%d) Packaging %d bytes (%d waiting).",conn->s,cell.length, conn->inbuf_datalen);
cell.command = CELL_RELAY;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_DATA);
SET_CELL_STREAM_ID(cell, conn->stream_id);
cell.length += RELAY_HEADER_SIZE;
if(conn->type == CONN_TYPE_EXIT) {
cell.aci = circ->p_aci;
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_IN, NULL) < 0) {
log_fn(LOG_DEBUG,"circuit_deliver_relay_cell (backward) failed. Closing.");
circuit_close(circ);
return 0;
}
assert(circ->package_window > 0);
circ->package_window--;
} else { /* send it forward. we're an AP */
assert(conn->type == CONN_TYPE_AP);
cell.aci = circ->n_aci;
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_OUT, conn->cpath_layer) < 0) {
log_fn(LOG_DEBUG,"circuit_deliver_relay_cell (forward) failed. Closing.");
circuit_close(circ);
return 0;
}
assert(conn->cpath_layer->package_window > 0);
conn->cpath_layer->package_window--;
}
assert(conn->package_window > 0);
if(--conn->package_window <= 0) { /* is it 0 after decrement? */
connection_stop_reading(conn);
log_fn(LOG_DEBUG,"conn->package_window reached 0.");
circuit_consider_stop_edge_reading(circ, conn->type, conn->cpath_layer);
return 0; /* don't process the inbuf any more */
}
log_fn(LOG_DEBUG,"conn->package_window is now %d",conn->package_window);
/* handle more if there's more, or return 0 if there isn't */
goto repeat_connection_package_raw_inbuf;
}
int connection_consider_sending_sendme(connection_t *conn, int edge_type) {
circuit_t *circ;
cell_t cell;
if(connection_outbuf_too_full(conn))
return 0;
circ = circuit_get_by_conn(conn);
if(!circ) {
/* this can legitimately happen if the destroy has already arrived and torn down the circuit */
log_fn(LOG_DEBUG,"No circuit associated with conn. Skipping.");
return 0;
}
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_SENDME);
SET_CELL_STREAM_ID(cell, conn->stream_id);
cell.length += RELAY_HEADER_SIZE;
if(edge_type == EDGE_EXIT)
cell.aci = circ->p_aci;
else
cell.aci = circ->n_aci;
while(conn->deliver_window < STREAMWINDOW_START - STREAMWINDOW_INCREMENT) {
log_fn(LOG_DEBUG,"Outbuf %d, Queueing stream sendme.", conn->outbuf_flushlen);
conn->deliver_window += STREAMWINDOW_INCREMENT;
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION(edge_type), conn->cpath_layer) < 0) {
log_fn(LOG_DEBUG,"circuit_deliver_relay_cell failed. Closing.");
circuit_close(circ);
return 0;
}
}
return 0;
}
static int connection_ap_handshake_process_socks(connection_t *conn) {
circuit_t *circ;
char destaddr[200]; /* XXX why 200? but not 256, because it won't fit in a cell */
uint16_t destport;
assert(conn);
log_fn(LOG_DEBUG,"entered.");
switch(fetch_from_buf_socks(conn->inbuf,&conn->inbuf_datalen,
destaddr, sizeof(destaddr), &destport)) {
case -1:
log_fn(LOG_DEBUG,"Fetching socks handshake failed. Closing.");
connection_ap_handshake_socks_reply(conn, SOCKS4_REQUEST_REJECT);
return -1;
case 0:
log_fn(LOG_DEBUG,"Fetching socks handshake, not all here yet. Ignoring.");
return 0;
/* case 1, fall through */
}
/* find the circuit that we should use, if there is one. */
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circ = circuit_get_newest_open();
if(!circ) {
log_fn(LOG_INFO,"No circuit ready. Closing.");
return -1;
}
circ->dirty = 1;
/* add it into the linked list of streams on this circuit */
log_fn(LOG_DEBUG,"attaching new conn to circ. n_aci %d.", circ->n_aci);
conn->next_stream = circ->p_streams;
circ->p_streams = conn;
assert(circ->cpath && circ->cpath->prev);
assert(circ->cpath->prev->state == CPATH_STATE_OPEN);
conn->cpath_layer = circ->cpath->prev;
if(connection_ap_handshake_send_begin(conn, circ, destaddr, destport) < 0) {
circuit_close(circ);
return -1;
}
return 0;
}
/* deliver the destaddr:destport in a relay cell */
static int connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t *circ,
char *destaddr, uint16_t destport) {
cell_t cell;
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
cell.aci = circ->n_aci;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_BEGIN);
if(crypto_pseudo_rand(STREAM_ID_SIZE, ap_conn->stream_id) < 0)
return -1;
/* FIXME check for collisions */
SET_CELL_STREAM_ID(cell, ZERO_STREAM);
memcpy(cell.payload+RELAY_HEADER_SIZE, ap_conn->stream_id, STREAM_ID_SIZE);
cell.length =
snprintf(cell.payload+RELAY_HEADER_SIZE+STREAM_ID_SIZE, CELL_PAYLOAD_SIZE-RELAY_HEADER_SIZE-STREAM_ID_SIZE,
"%s:%d", destaddr, destport) +
1 + STREAM_ID_SIZE + RELAY_HEADER_SIZE;
log_fn(LOG_DEBUG,"Sending relay cell (id %d) to begin stream %d.", *(int *)(cell.payload+1),*(int *)ap_conn->stream_id);
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_OUT, ap_conn->cpath_layer) < 0) {
log_fn(LOG_DEBUG,"failed to deliver begin cell. Closing.");
return -1;
}
ap_conn->package_window = STREAMWINDOW_START;
ap_conn->deliver_window = STREAMWINDOW_START;
ap_conn->state = AP_CONN_STATE_OPEN;
log_fn(LOG_INFO,"Address/port sent, ap socket %d, n_aci %d",ap_conn->s,circ->n_aci);
return 0;
}
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static int connection_ap_handshake_socks_reply(connection_t *conn, char result) {
char buf[SOCKS4_NETWORK_LEN];
assert(conn);
/* an inlined socks4_pack() */
memset(buf,0,sizeof(buf));
buf[1] = result; /* command */
/* leave version, destport, destip zero */
if(connection_write_to_buf(buf, sizeof(buf), conn) < 0)
return -1;
return connection_flush_buf(conn); /* try to flush it, in case we're about to close the conn */
}
static int connection_exit_begin_conn(cell_t *cell, circuit_t *circ) {
connection_t *n_stream;
char *colon;
if(!memchr(cell->payload+RELAY_HEADER_SIZE+STREAM_ID_SIZE,0,cell->length-RELAY_HEADER_SIZE-STREAM_ID_SIZE)) {
log_fn(LOG_WARNING,"relay begin cell has no \\0. Dropping.");
return 0;
}
colon = strchr(cell->payload+RELAY_HEADER_SIZE+STREAM_ID_SIZE, ':');
if(!colon) {
log_fn(LOG_WARNING,"relay begin cell has no colon. Dropping.");
return 0;
}
*colon = 0;
if(!atoi(colon+1)) { /* bad port */
log_fn(LOG_DEBUG,"relay begin cell has invalid port. Dropping.");
return 0;
}
log_fn(LOG_DEBUG,"Creating new exit connection.");
n_stream = connection_new(CONN_TYPE_EXIT);
if(!n_stream) {
log_fn(LOG_DEBUG,"connection_new failed. Dropping.");
return 0;
}
memcpy(n_stream->stream_id, cell->payload + RELAY_HEADER_SIZE, STREAM_ID_SIZE);
n_stream->address = strdup(cell->payload + RELAY_HEADER_SIZE + STREAM_ID_SIZE);
n_stream->port = atoi(colon+1);
n_stream->state = EXIT_CONN_STATE_RESOLVING;
n_stream->receiver_bucket = -1; /* edge connections don't do receiver buckets */
n_stream->bandwidth = -1;
n_stream->s = -1; /* not yet valid */
n_stream->package_window = STREAMWINDOW_START;
n_stream->deliver_window = STREAMWINDOW_START;
if(connection_add(n_stream) < 0) { /* no space, forget it */
log_fn(LOG_DEBUG,"connection_add failed. Dropping.");
connection_free(n_stream);
return 0;
}
/* add it into the linked list of streams on this circuit */
n_stream->next_stream = circ->n_streams;
circ->n_streams = n_stream;
/* send it off to the gethostbyname farm */
switch(dns_resolve(n_stream)) {
case 1: /* resolve worked */
if(connection_exit_connect(n_stream) >= 0)
return 0;
/* else fall through */
case -1: /* resolve failed */
log_fn(LOG_DEBUG,"Couldn't queue resolve request.");
connection_remove(n_stream);
connection_free(n_stream);
case 0: /* resolve added to pending list */
;
}
return 0;
}
int connection_exit_connect(connection_t *conn) {
if(router_compare_to_exit_policy(conn) < 0) {
log_fn(LOG_INFO,"%s:%d failed exit policy. Closing.", conn->address, conn->port);
return -1;
}
switch(connection_connect(conn, conn->address, conn->addr, conn->port)) {
case -1:
return -1;
case 0:
connection_set_poll_socket(conn);
conn->state = EXIT_CONN_STATE_CONNECTING;
connection_watch_events(conn, POLLOUT | POLLIN | POLLERR);
/* writable indicates finish, readable indicates broken link,
error indicates broken link in windowsland. */
return 0;
/* case 1: fall through */
}
connection_set_poll_socket(conn);
conn->state = EXIT_CONN_STATE_OPEN;
if(connection_wants_to_flush(conn)) { /* in case there are any queued data cells */
log_fn(LOG_ERR,"tell roger: newly connected conn had data waiting!");
// connection_start_writing(conn);
}
// connection_process_inbuf(conn);
connection_watch_events(conn, POLLIN);
/* also, deliver a 'connected' cell back through the circuit. */
return connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_CONNECTED);
}
/*
Local Variables:
mode:c
indent-tabs-mode:nil
c-basic-offset:2
End:
*/