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freeswitch/src/switch_stun.c

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/*
* FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
* Copyright (C) 2005-2012, Anthony Minessale II <anthm@freeswitch.org>
*
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
*
* The Initial Developer of the Original Code is
* Anthony Minessale II <anthm@freeswitch.org>
* Portions created by the Initial Developer are Copyright (C)
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Anthony Minessale II <anthm@freeswitch.org>
* Fanzhou Zhao <fanzhou@gmail.com> 2006-08-22 (Bugfix 2357-2358)
*
*
* switch_stun.c STUN (Simple Traversal of UDP over NAT)
*
*/
#include <switch.h>
#include <switch_stun.h>
struct value_mapping {
const uint32_t value;
const char *name;
};
static const struct value_mapping PACKET_TYPES[] = {
{SWITCH_STUN_BINDING_REQUEST, "BINDING_REQUEST"},
{SWITCH_STUN_BINDING_RESPONSE, "BINDING_RESPONSE"},
{SWITCH_STUN_BINDING_ERROR_RESPONSE, "BINDING_ERROR_RESPONSE"},
{SWITCH_STUN_SHARED_SECRET_REQUEST, "SHARED_SECRET_REQUEST"},
{SWITCH_STUN_SHARED_SECRET_RESPONSE, "SHARED_SECRET_RESPONSE"},
{SWITCH_STUN_SHARED_SECRET_ERROR_RESPONSE, "SHARED_SECRET_ERROR_RESPONSE"},
{SWITCH_STUN_ALLOCATE_REQUEST, "ALLOCATE_REQUEST"},
{SWITCH_STUN_ALLOCATE_RESPONSE, "ALLOCATE_RESPONSE"},
{SWITCH_STUN_ALLOCATE_ERROR_RESPONSE, "ALLOCATE_ERROR_RESPONSE"},
{SWITCH_STUN_SEND_REQUEST, "SEND_REQUEST"},
{SWITCH_STUN_SEND_RESPONSE, "SEND_RESPONSE"},
{SWITCH_STUN_SEND_ERROR_RESPONSE, "SEND_ERROR_RESPONSE"},
{SWITCH_STUN_DATA_INDICATION, "DATA_INDICATION"},
{0, 0}
};
static const struct value_mapping ATTR_TYPES[] = {
{SWITCH_STUN_ATTR_MAPPED_ADDRESS, "MAPPED_ADDRESS"},
{SWITCH_STUN_ATTR_RESPONSE_ADDRESS, "RESPONSE_ADDRESS"},
{SWITCH_STUN_ATTR_CHANGE_REQUEST, "CHANGE_REQUEST"},
{SWITCH_STUN_ATTR_SOURCE_ADDRESS, "SOURCE_ADDRESS"},
{SWITCH_STUN_ATTR_CHANGED_ADDRESS, "CHANGED_ADDRESS"},
{SWITCH_STUN_ATTR_USERNAME, "USERNAME"},
{SWITCH_STUN_ATTR_PASSWORD, "PASSWORD"},
{SWITCH_STUN_ATTR_MESSAGE_INTEGRITY, "MESSAGE_INTEGRITY"},
{SWITCH_STUN_ATTR_ERROR_CODE, "ERROR_CODE"},
{SWITCH_STUN_ATTR_UNKNOWN_ATTRIBUTES, "UNKNOWN_ATTRIBUTES"},
{SWITCH_STUN_ATTR_REFLECTED_FROM, "REFLECTED_FROM"},
{SWITCH_STUN_ATTR_TRANSPORT_PREFERENCES, "TRANSPORT_PREFERENCES"},
{SWITCH_STUN_ATTR_LIFETIME, "LIFETIME"},
{SWITCH_STUN_ATTR_ALTERNATE_SERVER, "ALTERNATE_SERVER"},
{SWITCH_STUN_ATTR_MAGIC_COOKIE, "MAGIC_COOKIE"},
{SWITCH_STUN_ATTR_BANDWIDTH, "BANDWIDTH"},
{SWITCH_STUN_ATTR_DESTINATION_ADDRESS, "DESTINATION_ADDRESS"},
{SWITCH_STUN_ATTR_SOURCE_ADDRESS2, "SOURCE_ADDRESS2"},
{SWITCH_STUN_ATTR_DATA, "DATA"},
{SWITCH_STUN_ATTR_OPTIONS, "OPTIONS"},
{0, 0}
};
static const struct value_mapping ERROR_TYPES[] = {
{SWITCH_STUN_ERROR_BAD_REQUEST, "BAD_REQUEST"},
{SWITCH_STUN_ERROR_UNAUTHORIZED, "UNAUTHORIZED"},
{SWITCH_STUN_ERROR_UNKNOWN_ATTRIBUTE, "UNKNOWN_ATTRIBUTE"},
{SWITCH_STUN_ERROR_STALE_CREDENTIALS, "STALE_CREDENTIALS"},
{SWITCH_STUN_ERROR_INTEGRITY_CHECK_FAILURE, "INTEGRITY_CHECK_FAILURE"},
{SWITCH_STUN_ERROR_MISSING_USERNAME, "MISSING_USERNAME"},
{SWITCH_STUN_ERROR_USE_TLS, "USE_TLS"},
{SWITCH_STUN_ERROR_SERVER_ERROR, "SERVER_ERROR"},
{SWITCH_STUN_ERROR_GLOBAL_FAILURE, "GLOBAL_FAILURE"},
{0, 0}
};
SWITCH_DECLARE(void) switch_stun_random_string(char *buf, uint16_t len, char *set)
{
char chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
int max;
uint16_t x;
if (!set) {
set = chars;
}
max = (int) strlen(set);
for (x = 0; x < len; x++) {
int j = (int) (max * 1.0 * rand() / (RAND_MAX + 1.0));
buf[x] = set[j];
}
}
SWITCH_DECLARE(switch_stun_packet_t *) switch_stun_packet_parse(uint8_t *buf, uint32_t len)
{
switch_stun_packet_t *packet;
switch_stun_packet_attribute_t *attr;
uint32_t bytes_left = len;
void *end_buf = buf + len;
if (len < SWITCH_STUN_PACKET_MIN_LEN) {
return NULL;
}
packet = (switch_stun_packet_t *) buf;
packet->header.type = ntohs(packet->header.type);
packet->header.length = ntohs(packet->header.length);
bytes_left -= packet->header.length + 20;
/*
* Check packet type (RFC3489(bis?) values)
*/
switch (packet->header.type) {
case SWITCH_STUN_BINDING_REQUEST:
case SWITCH_STUN_BINDING_RESPONSE:
case SWITCH_STUN_BINDING_ERROR_RESPONSE:
case SWITCH_STUN_SHARED_SECRET_REQUEST:
case SWITCH_STUN_SHARED_SECRET_RESPONSE:
case SWITCH_STUN_SHARED_SECRET_ERROR_RESPONSE:
case SWITCH_STUN_ALLOCATE_REQUEST:
case SWITCH_STUN_ALLOCATE_RESPONSE:
case SWITCH_STUN_ALLOCATE_ERROR_RESPONSE:
case SWITCH_STUN_SEND_REQUEST:
case SWITCH_STUN_SEND_RESPONSE:
case SWITCH_STUN_SEND_ERROR_RESPONSE:
case SWITCH_STUN_DATA_INDICATION:
/* Valid */
break;
default:
/* Invalid value */
return NULL;
}
/*
* Check for length overflow
*/
if (bytes_left <= 0) {
/* Invalid */
return NULL;
}
/*
* No payload?
*/
if (packet->header.length == 0) {
/* Invalid?! */
return NULL;
}
/* check if we have enough bytes left for an attribute */
if (bytes_left < SWITCH_STUN_ATTRIBUTE_MIN_LEN) {
return NULL;
}
switch_stun_packet_first_attribute(packet, attr);
do {
attr->length = ntohs(attr->length);
attr->type = ntohs(attr->type);
bytes_left -= 4; /* attribute header consumed */
if (!attr->length || switch_stun_attribute_padded_length(attr) > bytes_left) {
/*
* Note we simply don't "break" here out of the loop anymore because
* we don't want the upper layers to have to deal with attributes without a value
* (or worse: invalid length)
*/
return NULL;
}
/*
* Handle STUN attributes
*/
switch (attr->type) {
case SWITCH_STUN_ATTR_MAPPED_ADDRESS: /* Address, we only care about this one, but parse the others too */
case SWITCH_STUN_ATTR_RESPONSE_ADDRESS:
case SWITCH_STUN_ATTR_SOURCE_ADDRESS:
case SWITCH_STUN_ATTR_CHANGED_ADDRESS:
case SWITCH_STUN_ATTR_REFLECTED_FROM:
case SWITCH_STUN_ATTR_ALTERNATE_SERVER:
case SWITCH_STUN_ATTR_DESTINATION_ADDRESS:
case SWITCH_STUN_ATTR_SOURCE_ADDRESS2:
{
switch_stun_ip_t *ip;
uint32_t addr_length = 0;
ip = (switch_stun_ip_t *) attr->value;
switch (ip->family) {
case 0x01: /* IPv4 */
addr_length = 4;
break;
case 0x02: /* IPv6 */
addr_length = 16;
break;
default: /* Invalid */
return NULL;
}
/* attribute payload length must be == address length + size of other payload fields (family...) */
if (attr->length != addr_length + 4) {
/* Invalid */
return NULL;
}
ip->port = ntohs(ip->port);
}
break;
case SWITCH_STUN_ATTR_CHANGE_REQUEST: /* UInt32 */
case SWITCH_STUN_ATTR_LIFETIME:
case SWITCH_STUN_ATTR_BANDWIDTH:
case SWITCH_STUN_ATTR_OPTIONS:
{
uint32_t *val = (uint32_t *) attr->value;
if (attr->length != sizeof(uint32_t)) {
/* Invalid */
return NULL;
}
*val = ntohl(*val); /* should we do this here? */
}
break;
case SWITCH_STUN_ATTR_USERNAME: /* ByteString, multiple of 4 bytes */
case SWITCH_STUN_ATTR_PASSWORD: /* ByteString, multiple of 4 bytes */
if (attr->length % 4 != 0) {
/* Invalid */
return NULL;
}
break;
case SWITCH_STUN_ATTR_DATA: /* ByteString */
case SWITCH_STUN_ATTR_ERROR_CODE: /* ErrorCode */
case SWITCH_STUN_ATTR_TRANSPORT_PREFERENCES: /* TransportPrefs */
/*
* No length checking here, since we already checked against the padded length
* before
*/
break;
case SWITCH_STUN_ATTR_MESSAGE_INTEGRITY: /* ByteString, 20 bytes */
if (attr->length != 20) {
/* Invalid */
return NULL;
}
break;
case SWITCH_STUN_ATTR_MAGIC_COOKIE: /* ByteString, 4 bytes */
if (attr->length != 4) {
/* Invalid */
return NULL;
}
break;
case SWITCH_STUN_ATTR_UNKNOWN_ATTRIBUTES: /* UInt16List (= multiple of 2 bytes) */
if (attr->length % 2 != 0) {
return NULL;
}
break;
default:
/* Mandatory attribute range? => invalid */
if (attr->type <= 0x7FFF) {
return NULL;
}
break;
}
bytes_left -= switch_stun_attribute_padded_length(attr); /* attribute value consumed, substract padded length */
} while (bytes_left >= SWITCH_STUN_ATTRIBUTE_MIN_LEN && switch_stun_packet_next_attribute(attr, end_buf));
if ((uint32_t) (packet->header.length + 20) > (uint32_t) (len - bytes_left)) {
/*
* the packet length is longer than the length of all attributes?
* for now simply decrease the packet size
*/
packet->header.length = (uint16_t) ((len - bytes_left) - 20);
}
return packet;
}
SWITCH_DECLARE(const char *) switch_stun_value_to_name(int32_t type, uint32_t value)
{
uint32_t x = 0;
const struct value_mapping *map = NULL;
switch (type) {
case SWITCH_STUN_TYPE_PACKET_TYPE:
map = PACKET_TYPES;
break;
case SWITCH_STUN_TYPE_ATTRIBUTE:
map = ATTR_TYPES;
break;
case SWITCH_STUN_TYPE_ERROR:
map = ERROR_TYPES;
break;
default:
map = NULL;
break;
}
if (map) {
for (x = 0; map[x].value; x++) {
if (map[x].value == value) {
return map[x].name;
}
}
}
return "INVALID";
}
SWITCH_DECLARE(uint8_t) switch_stun_packet_attribute_get_mapped_address(switch_stun_packet_attribute_t *attribute, char *ipstr, uint16_t *port)
{
switch_stun_ip_t *ip;
uint8_t x, *i;
char *p = ipstr;
ip = (switch_stun_ip_t *) attribute->value;
i = (uint8_t *) & ip->address;
*ipstr = 0;
for (x = 0; x < 4; x++) {
sprintf(p, "%u%s", i[x], x == 3 ? "" : ".");
p = ipstr + strlen(ipstr);
}
*port = ip->port;
return 1;
}
SWITCH_DECLARE(char *) switch_stun_packet_attribute_get_username(switch_stun_packet_attribute_t *attribute, char *username, uint16_t len)
{
uint16_t cpylen;
cpylen = attribute->length < len ? attribute->length : len;
return memcpy(username, attribute->value, cpylen);
}
SWITCH_DECLARE(switch_stun_packet_t *) switch_stun_packet_build_header(switch_stun_message_t type, char *id, uint8_t *buf)
{
switch_stun_packet_header_t *header;
header = (switch_stun_packet_header_t *) buf;
header->type = htons(type);
header->length = 0;
if (id) {
memcpy(header->id, id, 16);
} else {
switch_stun_random_string(header->id, 16, NULL);
}
return (switch_stun_packet_t *) buf;
}
SWITCH_DECLARE(uint8_t) switch_stun_packet_attribute_add_binded_address(switch_stun_packet_t *packet, char *ipstr, uint16_t port)
{
switch_stun_packet_attribute_t *attribute;
switch_stun_ip_t *ip;
uint8_t *i, x;
char *p = ipstr;
attribute = (switch_stun_packet_attribute_t *) ((uint8_t *) & packet->first_attribute + ntohs(packet->header.length));
attribute->type = htons(SWITCH_STUN_ATTR_MAPPED_ADDRESS);
attribute->length = htons(8);
ip = (switch_stun_ip_t *) attribute->value;
ip->port = htons(port);
ip->family = 1;
i = (uint8_t *) & ip->address;
for (x = 0; x < 4; x++) {
i[x] = (uint8_t) atoi(p);
if ((p = strchr(p, '.'))) {
p++;
} else {
break;
}
}
packet->header.length += htons(sizeof(switch_stun_packet_attribute_t)) + attribute->length;
return 1;
}
SWITCH_DECLARE(uint8_t) switch_stun_packet_attribute_add_username(switch_stun_packet_t *packet, char *username, uint16_t ulen)
{
switch_stun_packet_attribute_t *attribute;
if (ulen % 4 != 0) {
return 0;
}
attribute = (switch_stun_packet_attribute_t *) ((uint8_t *) & packet->first_attribute + ntohs(packet->header.length));
attribute->type = htons(SWITCH_STUN_ATTR_USERNAME);
attribute->length = htons(ulen);
if (username) {
memcpy(attribute->value, username, ulen);
} else {
switch_stun_random_string(attribute->value, ulen, NULL);
}
packet->header.length += htons(sizeof(switch_stun_packet_attribute_t)) + attribute->length;
return 1;
}
SWITCH_DECLARE(char *) switch_stun_host_lookup(const char *host, switch_memory_pool_t *pool)
{
switch_sockaddr_t *addr = NULL;
char buf[30];
switch_sockaddr_info_get(&addr, host, SWITCH_UNSPEC, 0, 0, pool);
return switch_core_strdup(pool, switch_str_nil(switch_get_addr(buf, sizeof(buf), addr)));
}
SWITCH_DECLARE(switch_status_t) switch_stun_lookup(char **ip,
switch_port_t *port, char *stunip, switch_port_t stunport, char **err, switch_memory_pool_t *pool)
{
switch_sockaddr_t *local_addr = NULL, *remote_addr = NULL, *from_addr = NULL;
switch_socket_t *sock = NULL;
uint8_t buf[260] = { 0 };
uint8_t *start = buf;
void *end_buf;
switch_stun_packet_t *packet;
switch_stun_packet_attribute_t *attr;
switch_size_t bytes = 0;
char username[33] = { 0 };
char rip[16] = { 0 };
uint16_t rport = 0;
switch_time_t started = 0;
unsigned int elapsed = 0;
int funny = 0;
int size = sizeof(buf);
switch_assert(err);
if (*err && !strcmp(*err, "funny")) {
funny = 1;
}
*err = "Success";
switch_sockaddr_info_get(&from_addr, NULL, SWITCH_UNSPEC, 0, 0, pool);
if (switch_sockaddr_info_get(&local_addr, *ip, SWITCH_UNSPEC, *port, 0, pool) != SWITCH_STATUS_SUCCESS) {
*err = "Local Address Error!";
return SWITCH_STATUS_FALSE;
}
if (switch_sockaddr_info_get(&remote_addr, stunip, SWITCH_UNSPEC, stunport, 0, pool) != SWITCH_STATUS_SUCCESS) {
*err = "Remote Address Error!";
return SWITCH_STATUS_FALSE;
}
if (switch_socket_create(&sock, AF_INET, SOCK_DGRAM, 0, pool) != SWITCH_STATUS_SUCCESS) {
*err = "Socket Error!";
return SWITCH_STATUS_FALSE;
}
if (switch_socket_bind(sock, local_addr) != SWITCH_STATUS_SUCCESS) {
*err = "Bind Error!";
return SWITCH_STATUS_FALSE;
}
if (funny) {
*start++ = 0;
*start++ = 0;
*start++ = 0x22;
*start++ = 0x22;
}
switch_socket_opt_set(sock, SWITCH_SO_NONBLOCK, TRUE);
packet = switch_stun_packet_build_header(SWITCH_STUN_BINDING_REQUEST, NULL, start);
switch_stun_random_string(username, 32, NULL);
switch_stun_packet_attribute_add_username(packet, username, 32);
bytes = switch_stun_packet_length(packet);
if (funny) {
packet = (switch_stun_packet_t *) buf;
bytes += 4;
buf[bytes++] = 0;
buf[bytes++] = 0;
buf[bytes++] = 0;
buf[bytes++] = 0;
}
switch_socket_sendto(sock, remote_addr, 0, (void *) packet, &bytes);
started = switch_micro_time_now();
*ip = NULL;
*port = 0;
for (;;) {
bytes = sizeof(buf);
if (switch_socket_recvfrom(from_addr, sock, 0, (char *) &buf, &bytes) == SWITCH_STATUS_SUCCESS && bytes > 0) {
break;
}
if ((elapsed = (unsigned int) ((switch_micro_time_now() - started) / 1000)) > 5000) {
*err = "Timeout";
switch_socket_shutdown(sock, SWITCH_SHUTDOWN_READWRITE);
switch_socket_close(sock);
return SWITCH_STATUS_TIMEOUT;
}
switch_cond_next();
}
switch_socket_close(sock);
if (funny) {
size -= 4;
}
packet = switch_stun_packet_parse(start, size);
if (!packet) {
*err = "Invalid STUN/ICE packet";
return SWITCH_STATUS_FALSE;
}
end_buf = buf + ((sizeof(buf) > packet->header.length) ? packet->header.length : sizeof(buf));
switch_stun_packet_first_attribute(packet, attr);
do {
switch (attr->type) {
case SWITCH_STUN_ATTR_MAPPED_ADDRESS:
if (attr->type) {
if (funny) {
switch_stun_ip_t *tmp = (switch_stun_ip_t *) attr->value;
tmp->address ^= ntohl(0xabcdabcd);
}
switch_stun_packet_attribute_get_mapped_address(attr, rip, &rport);
}
break;
case SWITCH_STUN_ATTR_USERNAME:
if (attr->type) {
switch_stun_packet_attribute_get_username(attr, username, 32);
}
break;
}
} while (switch_stun_packet_next_attribute(attr, end_buf));
if (packet->header.type == SWITCH_STUN_BINDING_RESPONSE) {
*ip = switch_core_strdup(pool, rip);
*port = rport;
return SWITCH_STATUS_SUCCESS;
} else {
*err = "Invalid Reply";
}
return SWITCH_STATUS_FALSE;
}
/* For Emacs:
* Local Variables:
* mode:c
* indent-tabs-mode:t
* tab-width:4
* c-basic-offset:4
* End:
* For VIM:
* vim:set softtabstop=4 shiftwidth=4 tabstop=4:
*/
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