mirror of
https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-11-11 13:43:47 +01:00
384 lines
11 KiB
C
384 lines
11 KiB
C
/* Copyright 2001,2002 Roger Dingledine, Matej Pfajfar. */
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/* See LICENSE for licensing information */
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/* $Id$ */
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#include "or.h"
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/********* START VARIABLES **********/
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static circuit_t *global_circuitlist=NULL;
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char *circuit_state_to_string[] = {
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"receiving the onion", /* 0 */
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"waiting to process create", /* 1 */
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"connecting to firsthop", /* 2 */
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"open" /* 3 */
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};
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/********* END VARIABLES ************/
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void circuit_add(circuit_t *circ) {
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if(!global_circuitlist) { /* first one */
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global_circuitlist = circ;
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circ->next = NULL;
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} else {
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circ->next = global_circuitlist;
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global_circuitlist = circ;
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}
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}
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void circuit_remove(circuit_t *circ) {
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circuit_t *tmpcirc;
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assert(circ && global_circuitlist);
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if(global_circuitlist == circ) {
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global_circuitlist = global_circuitlist->next;
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return;
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}
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for(tmpcirc = global_circuitlist;tmpcirc->next;tmpcirc = tmpcirc->next) {
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if(tmpcirc->next == circ) {
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tmpcirc->next = circ->next;
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return;
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}
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}
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}
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circuit_t *circuit_new(aci_t p_aci, connection_t *p_conn) {
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circuit_t *circ;
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circ = (circuit_t *)malloc(sizeof(circuit_t));
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if(!circ)
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return NULL;
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memset(circ,0,sizeof(circuit_t)); /* zero it out */
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circ->p_aci = p_aci;
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circ->p_conn = p_conn;
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circ->state = CIRCUIT_STATE_ONION_WAIT;
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/* ACIs */
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circ->p_aci = p_aci;
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/* circ->n_aci remains 0 because we haven't identified the next hop yet */
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circ->n_receive_window = RECEIVE_WINDOW_START;
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circ->p_receive_window = RECEIVE_WINDOW_START;
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circuit_add(circ);
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return circ;
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}
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void circuit_free(circuit_t *circ) {
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if (circ->n_crypto)
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crypto_free_cipher_env(circ->n_crypto);
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if (circ->p_crypto)
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crypto_free_cipher_env(circ->p_crypto);
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if(circ->onion)
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free(circ->onion);
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if(circ->cpath)
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circuit_free_cpath(circ->cpath, circ->cpathlen);
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free(circ);
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}
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void circuit_free_cpath(crypt_path_t **cpath, int cpathlen) {
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int i;
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for(i=0;i<cpathlen;i++)
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free(cpath[i]);
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free(cpath);
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}
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/* return 0 if can't get a unique aci. */
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aci_t get_unique_aci_by_addr_port(uint32_t addr, uint16_t port, int aci_type) {
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aci_t test_aci;
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connection_t *conn;
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try_again:
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log(LOG_DEBUG,"get_unique_aci_by_addr_port() trying to get a unique aci");
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crypto_pseudo_rand(2, (unsigned char *)&test_aci);
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if(aci_type == ACI_TYPE_LOWER && test_aci >= (2<<15))
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test_aci -= (2<<15);
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if(aci_type == ACI_TYPE_HIGHER && test_aci < (2<<15))
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test_aci += (2<<15);
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/* if aci_type == ACI_BOTH, don't filter any of it */
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if(test_aci == 0)
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goto try_again;
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conn = connection_exact_get_by_addr_port(addr,port);
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if(!conn) /* there can't be a conflict -- no connection of that sort yet */
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return test_aci;
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if(circuit_get_by_aci_conn(test_aci, conn))
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goto try_again;
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return test_aci;
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}
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int circuit_init(circuit_t *circ, int aci_type) {
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unsigned char iv[16];
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unsigned char digest1[20];
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unsigned char digest2[20];
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struct timeval start, end;
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int time_passed;
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assert(circ && circ->onion);
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log(LOG_DEBUG,"circuit_init(): starting");
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circ->n_port = ntohs(*(uint16_t *)(circ->onion+2));
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log(LOG_DEBUG,"circuit_init(): Set port to %u.",circ->n_port);
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circ->n_addr = ntohl(*(uint32_t *)(circ->onion+4));
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circ->p_f = *(circ->onion+1) >> 4; /* backf */
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log(LOG_DEBUG,"circuit_init(): Set BACKF to %u.",circ->p_f);
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circ->n_f = *(circ->onion+1) & 0x0f; /* forwf */
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log(LOG_DEBUG,"circuit_init(): Set FORWF to %u.",circ->n_f);
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circ->state = CIRCUIT_STATE_OPEN;
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log(LOG_DEBUG,"circuit_init(): aci_type = %u.",aci_type);
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gettimeofday(&start,NULL);
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circ->n_aci = get_unique_aci_by_addr_port(circ->n_addr, circ->n_port, aci_type);
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if(!circ->n_aci) {
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log(LOG_ERR,"circuit_init(): failed to get unique aci.");
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return -1;
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}
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gettimeofday(&end,NULL);
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if(end.tv_usec < start.tv_usec) {
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end.tv_sec--;
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end.tv_usec += 1000000;
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}
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time_passed = ((end.tv_sec - start.tv_sec)*1000000) + (end.tv_usec - start.tv_usec);
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if(time_passed > 1000) { /* more than 1ms */
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log(LOG_NOTICE,"circuit_init(): get_unique_aci just took %d us!",time_passed);
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}
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log(LOG_DEBUG,"circuit_init(): Chosen ACI %u.",circ->n_aci);
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/* keys */
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memset(iv, 0, 16);
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crypto_SHA_digest(circ->onion+12,16,digest1);
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crypto_SHA_digest(digest1,20,digest2);
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crypto_SHA_digest(digest2,20,digest1);
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log(LOG_DEBUG,"circuit_init(): Computed keys.");
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if (!(circ->p_crypto = create_onion_cipher(circ->p_f,digest2,iv,1))) {
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log(LOG_ERR,"Cipher initialization failed (ACI %u).",circ->n_aci);
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return -1;
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}
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if (!(circ->n_crypto = create_onion_cipher(circ->n_f, digest1, iv, 0))) {
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log(LOG_ERR,"Cipher initialization failed (ACI %u).",circ->n_aci);
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return -1;
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}
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log(LOG_DEBUG,"circuit_init(): Cipher initialization complete.");
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circ->expire = ntohl(*(uint32_t *)(circ->onion+8));
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return 0;
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}
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circuit_t *circuit_enumerate_by_naddr_nport(circuit_t *circ, uint32_t naddr, uint16_t nport) {
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if(!circ) /* use circ if it's defined, else start from the beginning */
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circ = global_circuitlist;
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else
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circ = circ->next;
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for( ;circ;circ = circ->next) {
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if(circ->n_addr == naddr && circ->n_port == nport)
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return circ;
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}
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return NULL;
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}
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circuit_t *circuit_get_by_aci_conn(aci_t aci, connection_t *conn) {
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circuit_t *circ;
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for(circ=global_circuitlist;circ;circ = circ->next) {
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if(circ->p_conn == conn && circ->p_aci == aci)
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return circ;
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if(circ->n_conn == conn && circ->n_aci == aci)
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return circ;
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}
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return NULL;
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}
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circuit_t *circuit_get_by_conn(connection_t *conn) {
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circuit_t *circ;
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for(circ=global_circuitlist;circ;circ = circ->next) {
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if(circ->p_conn == conn)
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return circ;
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if(circ->n_conn == conn)
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return circ;
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}
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return NULL;
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}
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int circuit_deliver_data_cell(cell_t *cell, circuit_t *circ, connection_t *conn, int crypt_type) {
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/* first decrypt cell->length */
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if(circuit_crypt(circ, &(cell->length), 1, crypt_type) < 0) {
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log(LOG_DEBUG,"circuit_deliver_data_cell(): length decryption failed. Dropping connection.");
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return -1;
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}
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/* then decrypt the payload */
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if(circuit_crypt(circ, (char *)&(cell->payload), CELL_PAYLOAD_SIZE, crypt_type) < 0) {
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log(LOG_DEBUG,"circuit_deliver_data_cell(): payload decryption failed. Dropping connection.");
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return -1;
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}
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if(conn->type == CONN_TYPE_EXIT) { /* send payload directly */
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// log(LOG_DEBUG,"circuit_deliver_data_cell(): Sending to exit.");
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return connection_exit_process_data_cell(cell, conn);
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}
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if(conn->type == CONN_TYPE_AP) { /* send payload directly */
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// log(LOG_DEBUG,"circuit_deliver_data_cell(): Sending to AP.");
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return connection_ap_process_data_cell(cell, conn);
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}
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/* else send it as a cell */
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// log(LOG_DEBUG,"circuit_deliver_data_cell(): Sending to connection.");
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return connection_write_cell_to_buf(cell, conn);
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}
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int circuit_crypt(circuit_t *circ, char *in, int inlen, char crypt_type) {
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char *out;
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int i;
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crypt_path_t *thishop;
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assert(circ && in);
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out = (char *)malloc(inlen);
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if(!out)
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return -1;
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if(crypt_type == 'e') {
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// log(LOG_DEBUG,"circuit_crypt(): Encrypting %d bytes.",inlen);
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if(circ->cpath) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */
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/* 'e' means we're preparing to send it out. */
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for (i=0; i < circ->cpathlen; i++) /* moving from last to first hop
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* Remember : cpath is in reverse order, i.e. last hop first
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*/
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{
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// log(LOG_DEBUG,"circuit_crypt() : Encrypting via cpath: Processing hop %u",circ->cpathlen-i);
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thishop = circ->cpath[i];
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/* encrypt */
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if(crypto_cipher_encrypt(thishop->f_crypto, in, inlen, (unsigned char *)out)) {
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log(LOG_ERR,"Error performing encryption:%s",crypto_perror());
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free(out);
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return -1;
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}
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/* copy ciphertext back to buf */
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memcpy(in,out,inlen);
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}
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} else { /* we're in the middle. Just one crypt. */
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if(crypto_cipher_encrypt(circ->p_crypto,in, inlen, out)) {
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log(LOG_ERR,"circuit_encrypt(): Encryption failed for ACI : %u (%s).",
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circ->p_aci, crypto_perror());
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free(out);
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return -1;
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}
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memcpy(in,out,inlen);
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}
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} else if(crypt_type == 'd') {
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// log(LOG_DEBUG,"circuit_crypt(): Decrypting %d bytes.",inlen);
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if(circ->cpath) { /* we're at the beginning of the circuit. We'll want to do layered crypts. */
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for (i=circ->cpathlen-1; i >= 0; i--) /* moving from first to last hop
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* Remember : cpath is in reverse order, i.e. last hop first
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*/
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{
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// log(LOG_DEBUG,"circuit_crypt() : Decrypting via cpath: Processing hop %u",circ->cpathlen-i);
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thishop = circ->cpath[i];
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/* encrypt */
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if(crypto_cipher_decrypt(thishop->b_crypto, in, inlen, out)) {
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log(LOG_ERR,"Error performing decryption:%s",crypto_perror());
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free(out);
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return -1;
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}
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/* copy ciphertext back to buf */
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memcpy(in,out,inlen);
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}
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} else { /* we're in the middle. Just one crypt. */
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if(crypto_cipher_decrypt(circ->n_crypto,in, inlen, out)) {
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log(LOG_ERR,"circuit_crypt(): Decryption failed for ACI : %u (%s).",
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circ->n_aci, crypto_perror());
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free(out);
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return -1;
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}
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memcpy(in,out,inlen);
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}
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}
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free(out);
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return 0;
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}
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void circuit_close(circuit_t *circ) {
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circuit_remove(circ);
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if(circ->n_conn)
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connection_send_destroy(circ->n_aci, circ->n_conn);
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if(circ->p_conn)
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connection_send_destroy(circ->p_aci, circ->p_conn);
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circuit_free(circ);
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}
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void circuit_about_to_close_connection(connection_t *conn) {
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/* send destroys for all circuits using conn */
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/* currently, we assume it's too late to flush conn's buf here.
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* down the road, maybe we'll consider that eof doesn't mean can't-write
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*/
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circuit_t *circ;
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while((circ = circuit_get_by_conn(conn))) {
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circuit_remove(circ);
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if(circ->n_conn == conn) /* it's closing in front of us */
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/* circ->p_conn should always be set */
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assert(circ->p_conn);
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connection_send_destroy(circ->p_aci, circ->p_conn);
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if(circ->p_conn == conn) /* it's closing behind us */
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if(circ->n_conn)
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connection_send_destroy(circ->n_aci, circ->n_conn);
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circuit_free(circ);
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}
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}
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void circuit_dump_by_conn(connection_t *conn) {
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circuit_t *circ;
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for(circ=global_circuitlist;circ;circ = circ->next) {
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if(circ->p_conn == conn) {
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printf("Conn %d has App-ward circuit: aci %d (other side %d), state %d (%s)\n",
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conn->poll_index, circ->p_aci, circ->n_aci, circ->state, circuit_state_to_string[circ->state]);
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}
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if(circ->n_conn == conn) {
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printf("Conn %d has Exit-ward circuit: aci %d (other side %d), state %d (%s)\n",
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conn->poll_index, circ->n_aci, circ->p_aci, circ->state, circuit_state_to_string[circ->state]);
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}
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}
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}
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