/** Parse an EXTEND or EXTEND2 cell (according to <b>command</b>) from the
* <b>payload_length</b> bytes of <b>payload</b> into <b>cell_out</b>. Return
* 0 on success, -1 on failure. */
int
extend_cell_parse(extend_cell_t *cell_out, const uint8_t command,
const uint8_t *payload, size_t payload_length)
{
tor_assert(cell_out);
tor_assert(payload);
if (payload_length > RELAY_PAYLOAD_SIZE)
return -1;
switch (command) {
case RELAY_COMMAND_EXTEND:
{
extend1_cell_body_t *cell = NULL;
if (extend1_cell_body_parse(&cell, payload, payload_length)<0 ||
cell == NULL) {
if (cell)
extend1_cell_body_free(cell);
return -1;
}
int r = extend_cell_from_extend1_cell_body(cell_out, cell);
extend1_cell_body_free(cell);
if (r < 0)
return r;
}
break;
case RELAY_COMMAND_EXTEND2:
{
extend2_cell_body_t *cell = NULL;
if (extend2_cell_body_parse(&cell, payload, payload_length) < 0 ||
cell == NULL) {
if (cell)
extend2_cell_body_free(cell);
return -1;
}
int r = extend_cell_from_extend2_cell_body(cell_out, cell);
extend2_cell_body_free(cell);
if (r < 0)
return r;
}
break;
default:
return -1;
}
return check_extend_cell(cell_out);
}
/** Parse an EXTEND or EXTEND2 cell (according to <b>command</b>) from the
* <b>payload_length</b> bytes of <b>payload</b> into <b>cell_out</b>. Return
* 0 on success, -1 on failure. */
int
extend_cell_parse(extend_cell_t *cell_out, const uint8_t command,
const uint8_t *payload, size_t payload_length)
{
const uint8_t *eop;
memset(cell_out, 0, sizeof(*cell_out));
if (payload_length > RELAY_PAYLOAD_SIZE)
return -1;
eop = payload + payload_length;
switch (command) {
case RELAY_COMMAND_EXTEND:
{
if (payload_length != 6 + TAP_ONIONSKIN_CHALLENGE_LEN + DIGEST_LEN)
return -1;
cell_out->cell_type = RELAY_COMMAND_EXTEND;
tor_addr_from_ipv4n(&cell_out->orport_ipv4.addr, get_uint32(payload));
cell_out->orport_ipv4.port = ntohs(get_uint16(payload+4));
tor_addr_make_unspec(&cell_out->orport_ipv6.addr);
if (tor_memeq(payload + 6, NTOR_CREATE_MAGIC, 16)) {
cell_out->create_cell.cell_type = CELL_CREATE2;
cell_out->create_cell.handshake_type = ONION_HANDSHAKE_TYPE_NTOR;
cell_out->create_cell.handshake_len = NTOR_ONIONSKIN_LEN;
memcpy(cell_out->create_cell.onionskin, payload + 22,
NTOR_ONIONSKIN_LEN);
} else {
cell_out->create_cell.cell_type = CELL_CREATE;
cell_out->create_cell.handshake_type = ONION_HANDSHAKE_TYPE_TAP;
cell_out->create_cell.handshake_len = TAP_ONIONSKIN_CHALLENGE_LEN;
memcpy(cell_out->create_cell.onionskin, payload + 6,
TAP_ONIONSKIN_CHALLENGE_LEN);
}
memcpy(cell_out->node_id, payload + 6 + TAP_ONIONSKIN_CHALLENGE_LEN,
DIGEST_LEN);
break;
}
case RELAY_COMMAND_EXTEND2:
{
uint8_t n_specs, spectype, speclen;
int i;
int found_ipv4 = 0, found_ipv6 = 0, found_id = 0;
tor_addr_make_unspec(&cell_out->orport_ipv4.addr);
tor_addr_make_unspec(&cell_out->orport_ipv6.addr);
if (payload_length == 0)
return -1;
cell_out->cell_type = RELAY_COMMAND_EXTEND2;
n_specs = *payload++;
/* Parse the specifiers. We'll only take the first IPv4 and first IPv6
* address, and the node ID, and ignore everything else */
for (i = 0; i < n_specs; ++i) {
if (eop - payload < 2)
return -1;
spectype = payload[0];
speclen = payload[1];
payload += 2;
if (eop - payload < speclen)
return -1;
switch (spectype) {
case SPECTYPE_IPV4:
if (speclen != 6)
return -1;
if (!found_ipv4) {
tor_addr_from_ipv4n(&cell_out->orport_ipv4.addr,
get_uint32(payload));
cell_out->orport_ipv4.port = ntohs(get_uint16(payload+4));
found_ipv4 = 1;
}
break;
case SPECTYPE_IPV6:
if (speclen != 18)
return -1;
if (!found_ipv6) {
tor_addr_from_ipv6_bytes(&cell_out->orport_ipv6.addr,
(const char*)payload);
cell_out->orport_ipv6.port = ntohs(get_uint16(payload+16));
found_ipv6 = 1;
}
break;
case SPECTYPE_LEGACY_ID:
if (speclen != 20)
return -1;
if (found_id)
return -1;
memcpy(cell_out->node_id, payload, 20);
found_id = 1;
break;
}
payload += speclen;
}
if (!found_id || !found_ipv4)
return -1;
if (parse_create2_payload(&cell_out->create_cell,payload,eop-payload)<0)
return -1;
break;
}
default:
return -1;
}
return check_extend_cell(cell_out);
}
/** Format the EXTEND{,2} cell in <b>cell_in</b>, storing its relay payload in
* <b>payload_out</b>, the number of bytes used in *<b>len_out</b>, and the
* relay command in *<b>command_out</b>. The <b>payload_out</b> must have
* RELAY_PAYLOAD_SIZE bytes available. Return 0 on success, -1 on failure. */
int
extend_cell_format(uint8_t *command_out, uint16_t *len_out,
uint8_t *payload_out, const extend_cell_t *cell_in)
{
uint8_t *p, *eop;
if (check_extend_cell(cell_in) < 0)
return -1;
p = payload_out;
eop = payload_out + RELAY_PAYLOAD_SIZE;
memset(p, 0, RELAY_PAYLOAD_SIZE);
switch (cell_in->cell_type) {
case RELAY_COMMAND_EXTEND:
{
*command_out = RELAY_COMMAND_EXTEND;
*len_out = 6 + TAP_ONIONSKIN_CHALLENGE_LEN + DIGEST_LEN;
set_uint32(p, tor_addr_to_ipv4n(&cell_in->orport_ipv4.addr));
set_uint16(p+4, ntohs(cell_in->orport_ipv4.port));
if (cell_in->create_cell.handshake_type == ONION_HANDSHAKE_TYPE_NTOR) {
memcpy(p+6, NTOR_CREATE_MAGIC, 16);
memcpy(p+22, cell_in->create_cell.onionskin, NTOR_ONIONSKIN_LEN);
} else {
memcpy(p+6, cell_in->create_cell.onionskin,
TAP_ONIONSKIN_CHALLENGE_LEN);
}
memcpy(p+6+TAP_ONIONSKIN_CHALLENGE_LEN, cell_in->node_id, DIGEST_LEN);
}
break;
case RELAY_COMMAND_EXTEND2:
{
uint8_t n = 2;
*command_out = RELAY_COMMAND_EXTEND2;
*p++ = n; /* 2 identifiers */
*p++ = SPECTYPE_IPV4; /* First is IPV4. */
*p++ = 6; /* It's 6 bytes long. */
set_uint32(p, tor_addr_to_ipv4n(&cell_in->orport_ipv4.addr));
set_uint16(p+4, htons(cell_in->orport_ipv4.port));
p += 6;
*p++ = SPECTYPE_LEGACY_ID; /* Next is an identity digest. */
*p++ = 20; /* It's 20 bytes long */
memcpy(p, cell_in->node_id, DIGEST_LEN);
p += 20;
/* Now we can send the handshake */
set_uint16(p, htons(cell_in->create_cell.handshake_type));
set_uint16(p+2, htons(cell_in->create_cell.handshake_len));
p += 4;
if (cell_in->create_cell.handshake_len > eop - p)
return -1;
memcpy(p, cell_in->create_cell.onionskin,
cell_in->create_cell.handshake_len);
p += cell_in->create_cell.handshake_len;
*len_out = p - payload_out;
}
break;
default:
return -1;
}
return 0;
}
/** Format the EXTEND{,2} cell in <b>cell_in</b>, storing its relay payload in
* <b>payload_out</b>, the number of bytes used in *<b>len_out</b>, and the
* relay command in *<b>command_out</b>. The <b>payload_out</b> must have
* RELAY_PAYLOAD_SIZE bytes available. Return 0 on success, -1 on failure. */
int
extend_cell_format(uint8_t *command_out, uint16_t *len_out,
uint8_t *payload_out, const extend_cell_t *cell_in)
{
uint8_t *p;
if (check_extend_cell(cell_in) < 0)
return -1;
p = payload_out;
memset(p, 0, RELAY_PAYLOAD_SIZE);
switch (cell_in->cell_type) {
case RELAY_COMMAND_EXTEND:
{
*command_out = RELAY_COMMAND_EXTEND;
*len_out = 6 + TAP_ONIONSKIN_CHALLENGE_LEN + DIGEST_LEN;
set_uint32(p, tor_addr_to_ipv4n(&cell_in->orport_ipv4.addr));
set_uint16(p+4, htons(cell_in->orport_ipv4.port));
if (cell_in->create_cell.handshake_type == ONION_HANDSHAKE_TYPE_NTOR) {
memcpy(p+6, NTOR_CREATE_MAGIC, 16);
memcpy(p+22, cell_in->create_cell.onionskin, NTOR_ONIONSKIN_LEN);
} else {
memcpy(p+6, cell_in->create_cell.onionskin,
TAP_ONIONSKIN_CHALLENGE_LEN);
}
memcpy(p+6+TAP_ONIONSKIN_CHALLENGE_LEN, cell_in->node_id, DIGEST_LEN);
}
break;
case RELAY_COMMAND_EXTEND2:
{
uint8_t n_specifiers = 2;
*command_out = RELAY_COMMAND_EXTEND2;
extend2_cell_body_t *cell = extend2_cell_body_new();
link_specifier_t *ls;
{
/* IPv4 specifier first. */
ls = link_specifier_new();
extend2_cell_body_add_ls(cell, ls);
ls->ls_type = LS_IPV4;
ls->ls_len = 6;
ls->un_ipv4_addr = tor_addr_to_ipv4h(&cell_in->orport_ipv4.addr);
ls->un_ipv4_port = cell_in->orport_ipv4.port;
}
{
/* Then RSA id */
ls = link_specifier_new();
extend2_cell_body_add_ls(cell, ls);
ls->ls_type = LS_LEGACY_ID;
ls->ls_len = DIGEST_LEN;
memcpy(ls->un_legacy_id, cell_in->node_id, DIGEST_LEN);
}
if (should_include_ed25519_id_extend_cells(NULL, get_options()) &&
!ed25519_public_key_is_zero(&cell_in->ed_pubkey)) {
/* Then, maybe, the ed25519 id! */
++n_specifiers;
ls = link_specifier_new();
extend2_cell_body_add_ls(cell, ls);
ls->ls_type = LS_ED25519_ID;
ls->ls_len = 32;
memcpy(ls->un_ed25519_id, cell_in->ed_pubkey.pubkey, 32);
}
cell->n_spec = n_specifiers;
/* Now, the handshake */
cell->create2 = create2_cell_body_new();
cell->create2->handshake_type = cell_in->create_cell.handshake_type;
cell->create2->handshake_len = cell_in->create_cell.handshake_len;
create2_cell_body_setlen_handshake_data(cell->create2,
cell_in->create_cell.handshake_len);
memcpy(create2_cell_body_getarray_handshake_data(cell->create2),
cell_in->create_cell.onionskin,
cell_in->create_cell.handshake_len);
ssize_t len_encoded = extend2_cell_body_encode(
payload_out, RELAY_PAYLOAD_SIZE,
cell);
extend2_cell_body_free(cell);
if (len_encoded < 0 || len_encoded > UINT16_MAX)
return -1;
*len_out = (uint16_t) len_encoded;
}
break;
default:
return -1;
}
return 0;
}
