nihilist/tor
1
0
Fork 0
mirror of https://gitlab.torproject.org/tpo/core/tor.git synced 2024-09-22 14:04:58 +02:00
Code Issues Packages Projects Releases Wiki Activity
17a311d9a0
tor/src/or/circuit.c
Nick Mathewson 17a311d9a0 Fix typo: ports are 16 bits. 
svn:r374
2003-08-11 19:48:22 +00:00

925 lines
28 KiB
C
Raw Blame History

/* 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 */
/********* START VARIABLES **********/
static circuit_t *global_circuitlist=NULL;
char *circuit_state_to_string[] = {
"receiving the onion", /* 0 */
"waiting to process create", /* 1 */
"connecting to firsthop", /* 2 */
"open" /* 3 */
};
/********* END VARIABLES ************/
void circuit_add(circuit_t *circ) {
if(!global_circuitlist) { /* first one */
global_circuitlist = circ;
circ->next = NULL;
} else {
circ->next = global_circuitlist;
global_circuitlist = circ;
}
}
void circuit_remove(circuit_t *circ) {
circuit_t *tmpcirc;
assert(circ && global_circuitlist);
if(global_circuitlist == circ) {
global_circuitlist = global_circuitlist->next;
return;
}
for(tmpcirc = global_circuitlist;tmpcirc->next;tmpcirc = tmpcirc->next) {
if(tmpcirc->next == circ) {
tmpcirc->next = circ->next;
return;
}
}
}
circuit_t *circuit_new(aci_t p_aci, connection_t *p_conn) {
circuit_t *circ;
struct timeval now;
my_gettimeofday(&now);
circ = (circuit_t *)tor_malloc(sizeof(circuit_t));
memset(circ,0,sizeof(circuit_t)); /* zero it out */
circ->timestamp_created = now.tv_sec;
circ->p_aci = p_aci;
circ->p_conn = p_conn;
circ->state = CIRCUIT_STATE_ONIONSKIN_PENDING;
/* ACIs */
circ->p_aci = p_aci;
/* circ->n_aci remains 0 because we haven't identified the next hop yet */
circ->package_window = CIRCWINDOW_START;
circ->deliver_window = CIRCWINDOW_START;
circuit_add(circ);
return circ;
}
void circuit_free(circuit_t *circ) {
if (circ->n_crypto)
crypto_free_cipher_env(circ->n_crypto);
if (circ->p_crypto)
crypto_free_cipher_env(circ->p_crypto);
circuit_free_cpath(circ->cpath);
free(circ);
}
void circuit_free_cpath(crypt_path_t *cpath) {
crypt_path_t *victim, *head=cpath;
if(!cpath)
return;
/* it's a doubly linked list, so we have to notice when we've
* gone through it once. */
while(cpath->next && cpath->next != head) {
victim = cpath;
cpath = victim->next;
circuit_free_cpath_node(victim);
}
circuit_free_cpath_node(cpath);
}
void circuit_free_cpath_node(crypt_path_t *victim) {
if(victim->f_crypto)
crypto_free_cipher_env(victim->f_crypto);
if(victim->b_crypto)
crypto_free_cipher_env(victim->b_crypto);
if(victim->handshake_state)
crypto_dh_free(victim->handshake_state);
free(victim);
}
/* return 0 if can't get a unique aci. */
aci_t get_unique_aci_by_addr_port(uint32_t addr, uint16_t port, int aci_type) {
aci_t test_aci;
connection_t *conn;
try_again:
log_fn(LOG_DEBUG,"trying to get a unique aci");
if (CRYPTO_PSEUDO_RAND_INT(test_aci))
return -1;
if(aci_type == ACI_TYPE_LOWER && test_aci >= (1<<15))
test_aci -= (1<<15);
if(aci_type == ACI_TYPE_HIGHER && test_aci < (1<<15))
test_aci += (1<<15);
/* if aci_type == ACI_BOTH, don't filter any of it */
if(test_aci == 0)
goto try_again;
conn = connection_exact_get_by_addr_port(addr,port);
if(!conn) /* there can't be a conflict -- no connection of that sort yet */
return test_aci;
if(circuit_get_by_aci_conn(test_aci, conn))
goto try_again;
return test_aci;
}
circuit_t *circuit_enumerate_by_naddr_nport(circuit_t *circ, uint32_t naddr, uint16_t nport) {
if(!circ) /* use circ if it's defined, else start from the beginning */
circ = global_circuitlist;
else
circ = circ->next;
for( ; circ; circ = circ->next) {
if(circ->n_addr == naddr && circ->n_port == nport)
return circ;
}
return NULL;
}
circuit_t *circuit_get_by_aci_conn(aci_t aci, connection_t *conn) {
circuit_t *circ;
connection_t *tmpconn;
for(circ=global_circuitlist;circ;circ = circ->next) {
if(circ->p_aci == aci) {
if(circ->p_conn == conn)
return circ;
for(tmpconn = circ->p_streams; tmpconn; tmpconn = tmpconn->next_stream) {
if(tmpconn == conn)
return circ;
}
}
if(circ->n_aci == aci) {
if(circ->n_conn == conn)
return circ;
for(tmpconn = circ->n_streams; tmpconn; tmpconn = tmpconn->next_stream) {
if(tmpconn == conn)
return circ;
}
}
}
return NULL;
}
circuit_t *circuit_get_by_conn(connection_t *conn) {
circuit_t *circ;
connection_t *tmpconn;
for(circ=global_circuitlist;circ;circ = circ->next) {
if(circ->p_conn == conn)
return circ;
if(circ->n_conn == conn)
return circ;
for(tmpconn = circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream)
if(tmpconn == conn)
return circ;
for(tmpconn = circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream)
if(tmpconn == conn)
return circ;
}
return NULL;
}
circuit_t *circuit_get_newest_ap(void) {
circuit_t *circ, *bestcirc=NULL;
for(circ=global_circuitlist;circ;circ = circ->next) {
if(circ->cpath && circ->state == CIRCUIT_STATE_OPEN && (!bestcirc ||
bestcirc->timestamp_created < circ->timestamp_created)) {
log_fn(LOG_DEBUG,"Choosing n_aci %d.", circ->n_aci);
assert(circ->n_aci);
bestcirc = circ;
}
}
return bestcirc;
}
int circuit_deliver_relay_cell(cell_t *cell, circuit_t *circ,
int cell_direction, crypt_path_t *layer_hint) {
connection_t *conn=NULL;
char recognized=0;
char buf[256];
assert(cell && circ);
assert(cell_direction == CELL_DIRECTION_OUT || cell_direction == CELL_DIRECTION_IN);
buf[0] = cell->length;
memcpy(buf+1, cell->payload, CELL_PAYLOAD_SIZE);
log_fn(LOG_DEBUG,"direction %d, streamid %d before crypt.", cell_direction, *(int*)(cell->payload+1));
if(relay_crypt(circ, buf, 1+CELL_PAYLOAD_SIZE, cell_direction, &layer_hint, &recognized, &conn) < 0) {
log_fn(LOG_DEBUG,"relay crypt failed. Dropping connection.");
return -1;
}
cell->length = buf[0];
memcpy(cell->payload, buf+1, CELL_PAYLOAD_SIZE);
if(recognized) {
if(cell_direction == CELL_DIRECTION_OUT) {
log_fn(LOG_DEBUG,"Sending to exit.");
return connection_edge_process_relay_cell(cell, circ, conn, EDGE_EXIT, NULL);
}
if(cell_direction == CELL_DIRECTION_IN) {
log_fn(LOG_DEBUG,"Sending to AP.");
return connection_edge_process_relay_cell(cell, circ, conn, EDGE_AP, layer_hint);
}
}
/* not recognized. pass it on. */
if(cell_direction == CELL_DIRECTION_OUT)
conn = circ->n_conn;
else
conn = circ->p_conn;
if(!conn) { //|| !connection_speaks_cells(conn)) {
log_fn(LOG_INFO,"Didn't recognize cell (%d), but circ stops here! Dropping.", *(int *)(cell->payload+1));
return 0;
}
log_fn(LOG_DEBUG,"Passing on unrecognized cell.");
return connection_write_cell_to_buf(cell, conn);
}
int relay_crypt(circuit_t *circ, char *in, int inlen, char cell_direction,
crypt_path_t **layer_hint, char *recognized, connection_t **conn) {
crypt_path_t *thishop;
char out[256];
assert(circ && in && recognized && conn);
assert(inlen < 256);
if(cell_direction == CELL_DIRECTION_IN) {
if(circ->cpath) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */
thishop = circ->cpath;
if(thishop->state != CPATH_STATE_OPEN) {
log_fn(LOG_INFO,"Relay cell before first created cell?");
return -1;
}
do { /* Remember: cpath is in forward order, that is, first hop first. */
assert(thishop);
log_fn(LOG_DEBUG,"before decrypt: %d",*(int*)(in+2));
/* decrypt */
if(crypto_cipher_decrypt(thishop->b_crypto, in, inlen, out)) {
log_fn(LOG_ERR,"Error performing decryption:%s",crypto_perror());
return -1;
}
memcpy(in,out,inlen);
log_fn(LOG_DEBUG,"after decrypt: %d",*(int*)(in+2));
if( (*recognized = relay_check_recognized(circ, cell_direction, in+2, conn))) {
*layer_hint = thishop;
return 0;
}
thishop = thishop->next;
} while(thishop != circ->cpath && thishop->state == CPATH_STATE_OPEN);
log_fn(LOG_INFO,"in-cell at OP not recognized. Dropping.");
return 0;
} else { /* we're in the middle. Just one crypt. */
log_fn(LOG_DEBUG,"before encrypt: %d",*(int*)(in+2));
if(crypto_cipher_encrypt(circ->p_crypto, in, inlen, out)) {
log_fn(LOG_ERR,"Encryption failed for ACI : %u (%s).",
circ->p_aci, crypto_perror());
return -1;
}
memcpy(in,out,inlen);
log_fn(LOG_DEBUG,"after encrypt: %d",*(int*)(in+2));
log_fn(LOG_DEBUG,"Skipping recognized check, because we're not the OP.");
/* don't check for recognized. only the OP can recognize a stream on the way back. */
}
} else if(cell_direction == CELL_DIRECTION_OUT) {
if(circ->cpath) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */
thishop = *layer_hint; /* we already know which layer, from when we package_raw_inbuf'ed */
/* moving from last to first hop */
do {
assert(thishop);
log_fn(LOG_DEBUG,"before encrypt: %d",*(int*)(in+2));
if(crypto_cipher_encrypt(thishop->f_crypto, in, inlen, out)) {
log_fn(LOG_ERR,"Error performing encryption:%s",crypto_perror());
return -1;
}
memcpy(in,out,inlen);
log_fn(LOG_DEBUG,"after encrypt: %d",*(int*)(in+2));
thishop = thishop->prev;
} while(thishop != circ->cpath->prev);
} else { /* we're in the middle. Just one crypt. */
if(crypto_cipher_decrypt(circ->n_crypto,in, inlen, out)) {
log_fn(LOG_ERR,"Decryption failed for ACI : %u (%s).",
circ->n_aci, crypto_perror());
return -1;
}
memcpy(in,out,inlen);
if( (*recognized = relay_check_recognized(circ, cell_direction, in+2, conn)))
return 0;
}
} else {
log_fn(LOG_ERR,"unknown cell direction %d.", cell_direction);
assert(0);
}
return 0;
}
int relay_check_recognized(circuit_t *circ, int cell_direction, char *stream, connection_t **conn) {
/* FIXME can optimize by passing thishop in */
connection_t *tmpconn;
if(!memcmp(stream,ZERO_STREAM,STREAM_ID_SIZE)) {
log_fn(LOG_DEBUG,"It's the zero stream. Recognized.");
return 1; /* the zero stream is always recognized */
}
log_fn(LOG_DEBUG,"not the zero stream.");
if(cell_direction == CELL_DIRECTION_OUT)
tmpconn = circ->n_streams;
else
tmpconn = circ->p_streams;
if(!tmpconn) {
log_fn(LOG_DEBUG,"No conns. Not recognized.");
return 0;
}
for( ; tmpconn; tmpconn=tmpconn->next_stream) {
if(!memcmp(stream,tmpconn->stream_id, STREAM_ID_SIZE)) {
log_fn(LOG_DEBUG,"recognized stream %d.", *(int*)stream);
*conn = tmpconn;
return 1;
}
log_fn(LOG_DEBUG,"considered stream %d, not it.",*(int*)tmpconn->stream_id);
}
log_fn(LOG_DEBUG,"Didn't recognize. Giving up.");
return 0;
}
void circuit_resume_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) {
connection_t *conn;
assert(edge_type == EDGE_EXIT || edge_type == EDGE_AP);
log_fn(LOG_DEBUG,"resuming");
if(edge_type == EDGE_EXIT)
conn = circ->n_streams;
else
conn = circ->p_streams;
for( ; conn; conn=conn->next_stream) {
if((edge_type == EDGE_EXIT && conn->package_window > 0) ||
(edge_type == EDGE_AP && conn->package_window > 0 && conn->cpath_layer == layer_hint)) {
connection_start_reading(conn);
connection_package_raw_inbuf(conn); /* handle whatever might still be on the inbuf */
if(circuit_consider_stop_edge_reading(circ, edge_type, layer_hint))
return;
}
}
}
/* returns 1 if the window is empty, else 0. If it's empty, tell edge conns to stop reading. */
int circuit_consider_stop_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) {
connection_t *conn = NULL;
assert(edge_type == EDGE_EXIT || edge_type == EDGE_AP);
assert(edge_type == EDGE_EXIT || layer_hint);
log_fn(LOG_DEBUG,"considering");
if(edge_type == EDGE_EXIT && circ->package_window <= 0)
conn = circ->n_streams;
else if(edge_type == EDGE_AP && layer_hint->package_window <= 0)
conn = circ->p_streams;
else
return 0;
for( ; conn; conn=conn->next_stream)
if(!layer_hint || conn->cpath_layer == layer_hint)
connection_stop_reading(conn);
log_fn(LOG_DEBUG,"yes. stopped.");
return 1;
}
int circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) {
cell_t cell;
assert(circ);
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_SENDME);
SET_CELL_STREAM_ID(cell, ZERO_STREAM);
cell.length = RELAY_HEADER_SIZE;
if(edge_type == EDGE_AP) { /* i'm the AP */
cell.aci = circ->n_aci;
while(layer_hint->deliver_window < CIRCWINDOW_START-CIRCWINDOW_INCREMENT) {
log_fn(LOG_DEBUG,"deliver_window %d, Queueing sendme forward.", layer_hint->deliver_window);
layer_hint->deliver_window += CIRCWINDOW_INCREMENT;
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_OUT, layer_hint) < 0) {
return -1;
}
}
} else if(edge_type == EDGE_EXIT) { /* i'm the exit */
cell.aci = circ->p_aci;
while(circ->deliver_window < CIRCWINDOW_START-CIRCWINDOW_INCREMENT) {
log_fn(LOG_DEBUG,"deliver_window %d, Queueing sendme back.", circ->deliver_window);
circ->deliver_window += CIRCWINDOW_INCREMENT;
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_IN, layer_hint) < 0) {
return -1;
}
}
}
return 0;
}
void circuit_close(circuit_t *circ) {
connection_t *conn;
circuit_t *youngest=NULL;
assert(circ);
if(options.APPort) {
youngest = circuit_get_newest_ap();
log_fn(LOG_DEBUG,"youngest %d, circ %d.",(int)youngest, (int)circ);
}
circuit_remove(circ);
if(circ->n_conn)
connection_send_destroy(circ->n_aci, circ->n_conn);
for(conn=circ->n_streams; conn; conn=conn->next_stream) {
connection_send_destroy(circ->n_aci, conn);
}
if(circ->p_conn)
connection_send_destroy(circ->n_aci, circ->p_conn);
for(conn=circ->p_streams; conn; conn=conn->next_stream) {
connection_send_destroy(circ->p_aci, conn);
}
if(options.APPort && youngest == circ) { /* check this after we've sent the destroys, to reduce races */
/* our current circuit just died. Launch another one pronto. */
log_fn(LOG_INFO,"Youngest circuit dying. Launching a replacement.");
circuit_launch_new(1);
}
circuit_free(circ);
}
void circuit_about_to_close_connection(connection_t *conn) {
/* send destroys for all circuits using conn */
/* currently, we assume it's too late to flush conn's buf here.
* down the road, maybe we'll consider that eof doesn't mean can't-write
*/
circuit_t *circ;
connection_t *prevconn;
if(!connection_speaks_cells(conn)) {
/* it's an edge conn. need to remove it from the linked list of
* conn's for this circuit. Send an 'end' relay command.
* But don't kill the circuit.
*/
circ = circuit_get_by_conn(conn);
if(!circ)
return;
if(conn == circ->p_streams) {
circ->p_streams = conn->next_stream;
goto send_end;
}
if(conn == circ->n_streams) {
circ->n_streams = conn->next_stream;
goto send_end;
}
for(prevconn = circ->p_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ;
if(prevconn && prevconn->next_stream) {
prevconn->next_stream = conn->next_stream;
goto send_end;
}
for(prevconn = circ->n_streams; prevconn && prevconn->next_stream && prevconn->next_stream != conn; prevconn = prevconn->next_stream) ;
if(prevconn && prevconn->next_stream) {
prevconn->next_stream = conn->next_stream;
goto send_end;
}
log_fn(LOG_ERR,"edge conn not in circuit's list?");
assert(0); /* should never get here */
send_end:
if(connection_edge_send_command(conn, circ, RELAY_COMMAND_END) < 0) {
log_fn(LOG_DEBUG,"sending end failed. Closing.");
circuit_close(circ);
}
return;
}
/* this connection speaks cells. We must close all the circuits on it. */
while((circ = circuit_get_by_conn(conn))) {
if(circ->n_conn == conn) /* it's closing in front of us */
circ->n_conn = NULL;
if(circ->p_conn == conn) /* it's closing behind us */
circ->p_conn = NULL;
circuit_close(circ);
}
}
/* FIXME this now leaves some out */
void circuit_dump_by_conn(connection_t *conn) {
circuit_t *circ;
connection_t *tmpconn;
for(circ=global_circuitlist;circ;circ = circ->next) {
if(circ->p_conn == conn)
printf("Conn %d has App-ward circuit: aci %d (other side %d), state %d (%s)\n",
conn->poll_index, circ->p_aci, circ->n_aci, circ->state, circuit_state_to_string[circ->state]);
for(tmpconn=circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream) {
if(tmpconn == conn) {
printf("Conn %d has App-ward circuit: aci %d (other side %d), state %d (%s)\n",
conn->poll_index, circ->p_aci, circ->n_aci, circ->state, circuit_state_to_string[circ->state]);
}
}
if(circ->n_conn == conn)
printf("Conn %d has Exit-ward circuit: aci %d (other side %d), state %d (%s)\n",
conn->poll_index, circ->n_aci, circ->p_aci, circ->state, circuit_state_to_string[circ->state]);
for(tmpconn=circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream) {
if(tmpconn == conn) {
printf("Conn %d has Exit-ward circuit: aci %d (other side %d), state %d (%s)\n",
conn->poll_index, circ->n_aci, circ->p_aci, circ->state, circuit_state_to_string[circ->state]);
}
}
}
}
void circuit_expire_unused_circuits(void) {
circuit_t *circ, *tmpcirc;
circuit_t *youngest;
youngest = circuit_get_newest_ap();
circ = global_circuitlist;
while(circ) {
tmpcirc = circ;
circ = circ->next;
if(tmpcirc != youngest && !tmpcirc->p_conn && !tmpcirc->p_streams) {
log_fn(LOG_DEBUG,"Closing n_aci %d",tmpcirc->n_aci);
circuit_close(tmpcirc);
}
}
}
/* failure_status code: negative means reset failures to 0. Other values mean
* add that value to the current number of failures, then if we don't have too
* many failures on record, try to make a new circuit.
*/
void circuit_launch_new(int failure_status) {
static int failures=0;
if(!options.APPort) /* we're not an application proxy. no need for circuits. */
return;
if(failure_status == -1) { /* I was called because a circuit succeeded */
failures = 0;
return;
}
failures += failure_status;
retry_circuit:
if(failures > 5) {
log_fn(LOG_INFO,"Giving up, %d failures.", failures);
return;
}
if(circuit_establish_circuit() < 0) {
failures++;
goto retry_circuit;
}
failures = 0;
return;
}
int circuit_establish_circuit(void) {
routerinfo_t *firsthop;
connection_t *n_conn;
circuit_t *circ;
circ = circuit_new(0, NULL); /* sets circ->p_aci and circ->p_conn */
circ->state = CIRCUIT_STATE_OR_WAIT;
circ->cpath = onion_generate_cpath(&firsthop);
if(!circ->cpath) {
log_fn(LOG_DEBUG,"Generating cpath failed.");
circuit_close(circ);
return -1;
}
/* now see if we're already connected to the first OR in 'route' */
log_fn(LOG_DEBUG,"Looking for firsthop '%s:%u'",
firsthop->address,firsthop->or_port);
n_conn = connection_twin_get_by_addr_port(firsthop->addr,firsthop->or_port);
if(!n_conn || n_conn->state != OR_CONN_STATE_OPEN) { /* not currently connected */
circ->n_addr = firsthop->addr;
circ->n_port = firsthop->or_port;
if(options.OnionRouter) { /* we would be connected if he were up. but he's not. */
log_fn(LOG_DEBUG,"Route's firsthop isn't connected.");
circuit_close(circ);
return -1;
}
if(!n_conn) { /* launch the connection */
n_conn = connection_or_connect(firsthop);
if(!n_conn) { /* connect failed, forget the whole thing */
log_fn(LOG_DEBUG,"connect to firsthop failed. Closing.");
circuit_close(circ);
return -1;
}
}
log_fn(LOG_DEBUG,"connecting in progress (or finished). Good.");
return 0; /* return success. The onion/circuit/etc will be taken care of automatically
* (may already have been) whenever n_conn reaches OR_CONN_STATE_OPEN.
*/
} else { /* it (or a twin) is already open. use it. */
circ->n_addr = n_conn->addr;
circ->n_port = n_conn->port;
circ->n_conn = n_conn;
log_fn(LOG_DEBUG,"Conn open. Delivering first onion skin.");
if(circuit_send_next_onion_skin(circ) < 0) {
log_fn(LOG_DEBUG,"circuit_send_next_onion_skin failed.");
circuit_close(circ);
return -1;
}
}
return 0;
}
/* find circuits that are waiting on me, if any, and get them to send the onion */
void circuit_n_conn_open(connection_t *or_conn) {
circuit_t *circ;
log_fn(LOG_DEBUG,"Starting.");
circ = circuit_enumerate_by_naddr_nport(NULL, or_conn->addr, or_conn->port);
for(;;) {
if(!circ)
return;
log_fn(LOG_DEBUG,"Found circ, sending onion skin.");
circ->n_conn = or_conn;
if(circuit_send_next_onion_skin(circ) < 0) {
log_fn(LOG_DEBUG,"circuit marked for closing.");
circuit_close(circ);
return; /* FIXME will want to try the other circuits too? */
}
circ = circuit_enumerate_by_naddr_nport(circ, or_conn->addr, or_conn->port);
}
}
int circuit_send_next_onion_skin(circuit_t *circ) {
cell_t cell;
crypt_path_t *hop;
routerinfo_t *router;
assert(circ && circ->cpath);
if(circ->cpath->state == CPATH_STATE_CLOSED) {
log_fn(LOG_DEBUG,"First skin; sending create cell.");
circ->n_aci = get_unique_aci_by_addr_port(circ->n_addr, circ->n_port, ACI_TYPE_BOTH);
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_CREATE;
cell.aci = circ->n_aci;
cell.length = DH_ONIONSKIN_LEN;
if(onion_skin_create(circ->n_conn->pkey, &(circ->cpath->handshake_state), cell.payload) < 0) {
log_fn(LOG_INFO,"onion_skin_create (first hop) failed.");
return -1;
}
if(connection_write_cell_to_buf(&cell, circ->n_conn) < 0) {
return -1;
}
circ->cpath->state = CPATH_STATE_AWAITING_KEYS;
circ->state = CIRCUIT_STATE_BUILDING;
log_fn(LOG_DEBUG,"first skin; finished sending create cell.");
} else {
assert(circ->cpath->state == CPATH_STATE_OPEN);
assert(circ->state == CIRCUIT_STATE_BUILDING);
log_fn(LOG_DEBUG,"starting to send subsequent skin.");
for(hop=circ->cpath->next;
hop != circ->cpath && hop->state == CPATH_STATE_OPEN;
hop=hop->next) ;
if(hop == circ->cpath) { /* done building the circuit. whew. */
circ->state = CIRCUIT_STATE_OPEN;
log_fn(LOG_DEBUG,"circuit built!");
return 0;
}
router = router_get_by_addr_port(hop->addr,hop->port);
if(!router) {
log_fn(LOG_INFO,"couldn't lookup router %d:%d",hop->addr,hop->port);
return -1;
}
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
cell.aci = circ->n_aci;
SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_EXTEND);
SET_CELL_STREAM_ID(cell, ZERO_STREAM);
cell.length = RELAY_HEADER_SIZE + 6 + DH_ONIONSKIN_LEN;
*(uint32_t*)(cell.payload+RELAY_HEADER_SIZE) = htonl(hop->addr);
*(uint16_t*)(cell.payload+RELAY_HEADER_SIZE+4) = htons(hop->port);
if(onion_skin_create(router->pkey, &(hop->handshake_state), cell.payload+RELAY_HEADER_SIZE+6) < 0) {
log_fn(LOG_INFO,"onion_skin_create failed.");
return -1;
}
log_fn(LOG_DEBUG,"Sending extend relay cell.");
/* send it to hop->prev, because it will transfer it to a create cell and then send to hop */
if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_OUT, hop->prev) < 0) {
log_fn(LOG_DEBUG,"failed to deliver extend cell. Closing.");
return -1;
}
hop->state = CPATH_STATE_AWAITING_KEYS;
}
return 0;
}
/* take the 'extend' cell, pull out addr/port plus the onion skin. Connect
* to the next hop, and pass it the onion skin in a create cell.
*/
int circuit_extend(cell_t *cell, circuit_t *circ) {
connection_t *n_conn;
aci_t aci_type;
struct sockaddr_in me; /* my router identity */
cell_t newcell;
if(circ->n_conn) {
log_fn(LOG_WARNING,"n_conn already set. Bug/attack. Closing.");
return -1;
}
circ->n_addr = ntohl(*(uint32_t*)(cell->payload+RELAY_HEADER_SIZE));
circ->n_port = ntohs(*(uint16_t*)(cell->payload+RELAY_HEADER_SIZE+4));
if(learn_my_address(&me) < 0)
return -1;
n_conn = connection_twin_get_by_addr_port(circ->n_addr,circ->n_port);
if(!n_conn || n_conn->type != CONN_TYPE_OR) {
/* i've disabled making connections through OPs, but it's definitely
* possible here. I'm not sure if it would be a bug or a feature. -RD
*/
/* note also that this will close circuits where the onion has the same
* router twice in a row in the path. i think that's ok. -RD
*/
log_fn(LOG_DEBUG,"Next router not connected. Closing.");
/* XXX later we should fail more gracefully here, like with a 'truncated' */
return -1;
}
circ->n_addr = n_conn->addr; /* these are different if we found a twin instead */
circ->n_port = n_conn->port;
circ->n_conn = n_conn;
log_fn(LOG_DEBUG,"n_conn is %s:%u",n_conn->address,n_conn->port);
aci_type = decide_aci_type(ntohl(me.sin_addr.s_addr), ntohs(me.sin_port),
circ->n_addr, circ->n_port);
log_fn(LOG_DEBUG,"aci_type = %u.",aci_type);
circ->n_aci = get_unique_aci_by_addr_port(circ->n_addr, circ->n_port, aci_type);
if(!circ->n_aci) {
log_fn(LOG_ERR,"failed to get unique aci.");
return -1;
}
log_fn(LOG_DEBUG,"Chosen ACI %u.",circ->n_aci);
memset(&newcell, 0, sizeof(cell_t));
newcell.command = CELL_CREATE;
newcell.aci = circ->n_aci;
newcell.length = DH_ONIONSKIN_LEN;
memcpy(newcell.payload, cell->payload+RELAY_HEADER_SIZE+6, DH_ONIONSKIN_LEN);
if(connection_write_cell_to_buf(&newcell, circ->n_conn) < 0) {
return -1;
}
return 0;
}
int circuit_finish_handshake(circuit_t *circ, char *reply) {
unsigned char iv[16];
unsigned char keys[32];
crypt_path_t *hop;
memset(iv, 0, 16);
assert(circ->cpath);
if(circ->cpath->state == CPATH_STATE_AWAITING_KEYS)
hop = circ->cpath;
else {
for(hop=circ->cpath->next;
hop != circ->cpath && hop->state == CPATH_STATE_OPEN;
hop=hop->next) ;
if(hop == circ->cpath) { /* got an extended when we're all done? */
log_fn(LOG_INFO,"got extended when circ already built? Weird.");
return 0;
}
}
assert(hop->state == CPATH_STATE_AWAITING_KEYS);
if(onion_skin_client_handshake(hop->handshake_state, reply, keys, 32) < 0) {
log_fn(LOG_ERR,"onion_skin_client_handshake failed.");
return -1;
}
crypto_dh_free(hop->handshake_state); /* don't need it anymore */
hop->handshake_state = NULL;
log_fn(LOG_DEBUG,"hop %d init cipher forward %d, backward %d.", (uint32_t)hop, *(uint32_t*)keys, *(uint32_t*)(keys+16));
if (!(hop->f_crypto =
crypto_create_init_cipher(CIRCUIT_CIPHER,keys,iv,1))) {
log(LOG_ERR,"Cipher initialization failed.");
return -1;
}
if (!(hop->b_crypto =
crypto_create_init_cipher(CIRCUIT_CIPHER,keys+16,iv,0))) {
log(LOG_ERR,"Cipher initialization failed.");
return -1;
}
hop->state = CPATH_STATE_OPEN;
log_fn(LOG_DEBUG,"Completed.");
return 0;
}
int circuit_truncated(circuit_t *circ, crypt_path_t *layer) {
crypt_path_t *victim;
connection_t *stream;
assert(circ);
assert(layer);
while(layer->next != circ->cpath) {
/* we need to clear out layer->next */
victim = layer->next;
log_fn(LOG_DEBUG, "Killing a layer of the cpath.");
for(stream = circ->p_streams; stream; stream=stream->next_stream) {
if(stream->cpath_layer == victim) {
log_fn(LOG_DEBUG, "Marking stream %d for close.", *(int*)stream->stream_id);
stream->marked_for_close = 1;
}
}
layer->next = victim->next;
circuit_free_cpath_node(victim);
}
log_fn(LOG_DEBUG, "Complete.");
return 0;
}
/*
Local Variables:
mode:c
indent-tabs-mode:nil
c-basic-offset:2
End:
*/
Reference in New Issue View Git Blame Copy Permalink