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mistserver/lib/stun.cpp
roxlu 7e8eb634e6 Implemented WebRTC
2021-10-19 22:29:39 +02:00

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#include "defines.h"
#include "stun.h"
#include "checksum.h" // for crc32
/* --------------------------------------- */
std::string stun_family_type_to_string(uint8_t type) {
switch (type) {
case STUN_IP4: { return "STUN_IP4"; }
case STUN_IP6: { return "STUN_IP6"; }
default: { return "UNKNOWN"; }
}
}
std::string stun_message_type_to_string(uint16_t type) {
switch (type) {
case STUN_MSG_TYPE_NONE: { return "STUN_MSG_TYPE_NONE"; }
case STUN_MSG_TYPE_BINDING_REQUEST: { return "STUN_MSG_TYPE_BINDING_REQUEST"; }
case STUN_MSG_TYPE_BINDING_RESPONSE_SUCCESS: { return "STUN_MSG_TYPE_BINDING_RESPONSE_SUCCESS"; }
case STUN_MSG_TYPE_BINDING_RESPONSE_ERROR: { return "STUN_MSG_TYPE_BINDING_RESPONSE_ERROR"; }
case STUN_MSG_TYPE_BINDING_INDICATION: { return "STUN_MSG_TYPE_BINDING_INDICATION"; }
default: { return "UNKNOWN"; }
}
}
std::string stun_attribute_type_to_string(uint16_t type) {
switch (type) {
case STUN_ATTR_TYPE_NONE: { return "STUN_ATTR_TYPE_NONE"; }
case STUN_ATTR_TYPE_MAPPED_ADDR: { return "STUN_ATTR_TYPE_MAPPED_ADDR"; }
case STUN_ATTR_TYPE_CHANGE_REQ: { return "STUN_ATTR_TYPE_CHANGE_REQ"; }
case STUN_ATTR_TYPE_USERNAME: { return "STUN_ATTR_TYPE_USERNAME"; }
case STUN_ATTR_TYPE_MESSAGE_INTEGRITY: { return "STUN_ATTR_TYPE_MESSAGE_INTEGRITY"; }
case STUN_ATTR_TYPE_ERR_CODE: { return "STUN_ATTR_TYPE_ERR_CODE"; }
case STUN_ATTR_TYPE_UNKNOWN_ATTRIBUTES: { return "STUN_ATTR_TYPE_UNKNOWN_ATTRIBUTES"; }
case STUN_ATTR_TYPE_CHANNEL_NUMBER: { return "STUN_ATTR_TYPE_CHANNEL_NUMBER"; }
case STUN_ATTR_TYPE_LIFETIME: { return "STUN_ATTR_TYPE_LIFETIME"; }
case STUN_ATTR_TYPE_XOR_PEER_ADDR: { return "STUN_ATTR_TYPE_XOR_PEER_ADDR"; }
case STUN_ATTR_TYPE_DATA: { return "STUN_ATTR_TYPE_DATA"; }
case STUN_ATTR_TYPE_REALM: { return "STUN_ATTR_TYPE_REALM"; }
case STUN_ATTR_TYPE_NONCE: { return "STUN_ATTR_TYPE_NONCE"; }
case STUN_ATTR_TYPE_XOR_RELAY_ADDRESS: { return "STUN_ATTR_TYPE_XOR_RELAY_ADDRESS"; }
case STUN_ATTR_TYPE_REQ_ADDRESS_FAMILY: { return "STUN_ATTR_TYPE_REQ_ADDRESS_FAMILY"; }
case STUN_ATTR_TYPE_EVEN_PORT: { return "STUN_ATTR_TYPE_EVEN_PORT"; }
case STUN_ATTR_TYPE_REQUESTED_TRANSPORT: { return "STUN_ATTR_TYPE_REQUESTED_TRANSPORT"; }
case STUN_ATTR_TYPE_DONT_FRAGMENT: { return "STUN_ATTR_TYPE_DONT_FRAGMENT"; }
case STUN_ATTR_TYPE_XOR_MAPPED_ADDRESS: { return "STUN_ATTR_TYPE_XOR_MAPPED_ADDRESS"; }
case STUN_ATTR_TYPE_RESERVATION_TOKEN: { return "STUN_ATTR_TYPE_RESERVATION_TOKEN"; }
case STUN_ATTR_TYPE_PRIORITY: { return "STUN_ATTR_TYPE_PRIORITY"; }
case STUN_ATTR_TYPE_USE_CANDIDATE: { return "STUN_ATTR_TYPE_USE_CANDIDATE"; }
case STUN_ATTR_TYPE_PADDING: { return "STUN_ATTR_TYPE_PADDING"; }
case STUN_ATTR_TYPE_RESPONSE_PORT: { return "STUN_ATTR_TYPE_RESPONSE_PORT"; }
case STUN_ATTR_TYPE_SOFTWARE: { return "STUN_ATTR_TYPE_SOFTWARE"; }
case STUN_ATTR_TYPE_ALTERNATE_SERVER: { return "STUN_ATTR_TYPE_ALTERNATE_SERVER"; }
case STUN_ATTR_TYPE_FINGERPRINT: { return "STUN_ATTR_TYPE_FINGERPRINT"; }
case STUN_ATTR_TYPE_ICE_CONTROLLED: { return "STUN_ATTR_TYPE_ICE_CONTROLLED"; }
case STUN_ATTR_TYPE_ICE_CONTROLLING: { return "STUN_ATTR_TYPE_ICE_CONTROLLING"; }
case STUN_ATTR_TYPE_RESPONSE_ORIGIN: { return "STUN_ATTR_TYPE_RESPONSE_ORIGIN"; }
case STUN_ATTR_TYPE_OTHER_ADDRESS: { return "STUN_ATTR_TYPE_OTHER_ADDRESS"; }
default: { return "UNKNOWN"; }
}
}
static uint32_t poly_crc32(uint32_t inCrc, const uint8_t* data, size_t nbytes) {
static const unsigned long crc_table[256] = {
0x00000000,0x77073096,0xEE0E612C,0x990951BA,0x076DC419,0x706AF48F,0xE963A535,
0x9E6495A3,0x0EDB8832,0x79DCB8A4,0xE0D5E91E,0x97D2D988,0x09B64C2B,0x7EB17CBD,
0xE7B82D07,0x90BF1D91,0x1DB71064,0x6AB020F2,0xF3B97148,0x84BE41DE,0x1ADAD47D,
0x6DDDE4EB,0xF4D4B551,0x83D385C7,0x136C9856,0x646BA8C0,0xFD62F97A,0x8A65C9EC,
0x14015C4F,0x63066CD9,0xFA0F3D63,0x8D080DF5,0x3B6E20C8,0x4C69105E,0xD56041E4,
0xA2677172,0x3C03E4D1,0x4B04D447,0xD20D85FD,0xA50AB56B,0x35B5A8FA,0x42B2986C,
0xDBBBC9D6,0xACBCF940,0x32D86CE3,0x45DF5C75,0xDCD60DCF,0xABD13D59,0x26D930AC,
0x51DE003A,0xC8D75180,0xBFD06116,0x21B4F4B5,0x56B3C423,0xCFBA9599,0xB8BDA50F,
0x2802B89E,0x5F058808,0xC60CD9B2,0xB10BE924,0x2F6F7C87,0x58684C11,0xC1611DAB,
0xB6662D3D,0x76DC4190,0x01DB7106,0x98D220BC,0xEFD5102A,0x71B18589,0x06B6B51F,
0x9FBFE4A5,0xE8B8D433,0x7807C9A2,0x0F00F934,0x9609A88E,0xE10E9818,0x7F6A0DBB,
0x086D3D2D,0x91646C97,0xE6635C01,0x6B6B51F4,0x1C6C6162,0x856530D8,0xF262004E,
0x6C0695ED,0x1B01A57B,0x8208F4C1,0xF50FC457,0x65B0D9C6,0x12B7E950,0x8BBEB8EA,
0xFCB9887C,0x62DD1DDF,0x15DA2D49,0x8CD37CF3,0xFBD44C65,0x4DB26158,0x3AB551CE,
0xA3BC0074,0xD4BB30E2,0x4ADFA541,0x3DD895D7,0xA4D1C46D,0xD3D6F4FB,0x4369E96A,
0x346ED9FC,0xAD678846,0xDA60B8D0,0x44042D73,0x33031DE5,0xAA0A4C5F,0xDD0D7CC9,
0x5005713C,0x270241AA,0xBE0B1010,0xC90C2086,0x5768B525,0x206F85B3,0xB966D409,
0xCE61E49F,0x5EDEF90E,0x29D9C998,0xB0D09822,0xC7D7A8B4,0x59B33D17,0x2EB40D81,
0xB7BD5C3B,0xC0BA6CAD,0xEDB88320,0x9ABFB3B6,0x03B6E20C,0x74B1D29A,0xEAD54739,
0x9DD277AF,0x04DB2615,0x73DC1683,0xE3630B12,0x94643B84,0x0D6D6A3E,0x7A6A5AA8,
0xE40ECF0B,0x9309FF9D,0x0A00AE27,0x7D079EB1,0xF00F9344,0x8708A3D2,0x1E01F268,
0x6906C2FE,0xF762575D,0x806567CB,0x196C3671,0x6E6B06E7,0xFED41B76,0x89D32BE0,
0x10DA7A5A,0x67DD4ACC,0xF9B9DF6F,0x8EBEEFF9,0x17B7BE43,0x60B08ED5,0xD6D6A3E8,
0xA1D1937E,0x38D8C2C4,0x4FDFF252,0xD1BB67F1,0xA6BC5767,0x3FB506DD,0x48B2364B,
0xD80D2BDA,0xAF0A1B4C,0x36034AF6,0x41047A60,0xDF60EFC3,0xA867DF55,0x316E8EEF,
0x4669BE79,0xCB61B38C,0xBC66831A,0x256FD2A0,0x5268E236,0xCC0C7795,0xBB0B4703,
0x220216B9,0x5505262F,0xC5BA3BBE,0xB2BD0B28,0x2BB45A92,0x5CB36A04,0xC2D7FFA7,
0xB5D0CF31,0x2CD99E8B,0x5BDEAE1D,0x9B64C2B0,0xEC63F226,0x756AA39C,0x026D930A,
0x9C0906A9,0xEB0E363F,0x72076785,0x05005713,0x95BF4A82,0xE2B87A14,0x7BB12BAE,
0x0CB61B38,0x92D28E9B,0xE5D5BE0D,0x7CDCEFB7,0x0BDBDF21,0x86D3D2D4,0xF1D4E242,
0x68DDB3F8,0x1FDA836E,0x81BE16CD,0xF6B9265B,0x6FB077E1,0x18B74777,0x88085AE6,
0xFF0F6A70,0x66063BCA,0x11010B5C,0x8F659EFF,0xF862AE69,0x616BFFD3,0x166CCF45,
0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,
0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,
0x47B2CF7F,0x30B5FFE9,0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,
0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,
0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D
};
uint32_t crc32 = inCrc ^ 0xFFFFFFFF;
size_t i;
for (i = 0; i < nbytes; i++) {
crc32 = (crc32 >> 8) ^ crc_table[ (crc32 ^ data[i]) & 0xFF ];
}
return (crc32 ^ 0xFFFFFFFF);
}
/* --------------------------------------- */
int stun_compute_hmac_sha1(uint8_t* message, uint32_t nbytes, std::string key, uint8_t* output) {
int r = 0;
mbedtls_md_context_t md_ctx = { 0 };
const mbedtls_md_info_t *md_info = NULL;
if (NULL == message) {
FAIL_MSG("Can't compute hmac_sha1 as the input message is empty.");
return -1;
}
if (nbytes == 0) {
FAIL_MSG("Can't compute hmac_sha1 as the input length is invalid.");
return -2;
}
if (key.size() == 0) {
FAIL_MSG("Can't compute the hmac_sha1 as the key size is 0.");
return -3;
}
if (NULL == output) {
FAIL_MSG("Can't compute the hmac_sha as the output buffer is NULL.");
return -4;
}
md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA1);
if (!md_info) {
FAIL_MSG("Failed to find the MBEDTLS_MD_SHA1");
r = -5;
goto error;
}
r = mbedtls_md_setup(&md_ctx, md_info, 1);
if (r != 0) {
FAIL_MSG("Failed to setup the md context.");
r = -6;
goto error;
}
DONTEVEN_MSG("Calculating hmac-sha1 with key `%s` with size %zu over %zu bytes of data.", key.c_str(), key.size(), nbytes);
r = mbedtls_md_hmac_starts(&md_ctx, (const unsigned char*)key.c_str(), key.size());
if (r != 0) {
FAIL_MSG("Failed to start the hmac.");
r = -7;
goto error;
}
r = mbedtls_md_hmac_update(&md_ctx, (const unsigned char*)message, nbytes);
if (r != 0) {
FAIL_MSG("Failed to update the hmac.");
r = -8;
goto error;
}
r = mbedtls_md_hmac_finish(&md_ctx, output);
if (r != 0) {
FAIL_MSG("Failed to finish the hmac.");
r = -9;
goto error;
}
#if 0
printf("stun::compute_hmac_sha1 - verbose: computing hash over %u bytes, using key `%s`:\n", nbytes, key.c_str());
printf("-----------------------------------\n\t0: ");
int nl = 0, lines = 0;
for (int i = 0; i < nbytes; ++i, ++nl) {
if (nl == 4) {
printf("\n\t");
nl = 0;
lines++;
printf("%d: ", lines);
}
printf("%02X ", message[i]);
}
printf("\n-----------------------------------\n");
#endif
#if 0
printf("stun::compute_hmac_sha1 - verbose: computed hash: ");
int len = 20;
for(unsigned int i = 0; i < len; ++i) {
printf("%02X ", output[i]);
}
printf("\n");
#endif
error:
mbedtls_md_free(&md_ctx);
return r;
}
int stun_compute_message_integrity(std::vector<uint8_t>& buffer, std::string key, uint8_t* output) {
uint16_t dx = 20;
uint16_t offset = 0;
uint16_t len = 0;
uint16_t type = 0;
uint8_t curr_size[2];
if (0 == buffer.size()) {
FAIL_MSG("Cannot compute message integrity; buffer empty.");
return -1;
}
if (0 == key.size()) {
FAIL_MSG("Error: cannot compute message inegrity, key empty.");
return -2;
}
curr_size[0] = buffer[2];
curr_size[1] = buffer[3];
while (dx < buffer.size()) {
type |= buffer[dx + 1] & 0x00FF;
type |= (buffer[dx + 0] << 8) & 0xFF00;
dx += 2;
len |= (buffer[dx + 1] & 0x00FF);
len |= (buffer[dx + 0] << 8) & 0xFF00;
dx += 2;
offset = dx;
dx += len;
/* skip padding. */
while ( (dx & 0x03) != 0 && dx < buffer.size()) {
dx++;
}
if (type == STUN_ATTR_TYPE_MESSAGE_INTEGRITY) {
break;
}
type = 0;
len = 0;
}
/* rewrite Message-Length header field */
buffer[2] = (offset >> 8) & 0xFF;
buffer[3] = offset & 0xFF;
/*
and compute the sha1
we subtract the last 4 bytes, which are the attribute-type and
attribute-length of the Message-Integrity field which are not
used.
*/
if (0 != stun_compute_hmac_sha1(&buffer[0], offset - 4, key, output)) {
buffer[2] = curr_size[0];
buffer[3] = curr_size[1];
return -3;
}
/* rewrite message-length. */
buffer[2] = curr_size[0];
buffer[3] = curr_size[1];
return 0;
}
int stun_compute_fingerprint(std::vector<uint8_t>& buffer, uint32_t& result) {
uint32_t dx = 20;
uint16_t offset = 0;
uint16_t len = 0; /* messsage-length */
uint16_t type = 0;
uint8_t curr_size[2];
if (0 == buffer.size()) {
FAIL_MSG("Cannot compute fingerprint because the buffer is empty.");
return -1;
}
/* copy current message-length */
curr_size[0] = buffer[2];
curr_size[1] = buffer[3];
/* compute the size that should be used as Message-Length when computing the CRC32 */
while (dx < buffer.size()) {
type |= buffer[dx + 1] & 0x00FF;
type |= (buffer[dx + 0] << 8) & 0xFF00;
dx += 2;
len |= buffer[dx + 1] & 0x00FF;
len |= (buffer[dx + 0] << 8) & 0xFF00;
dx += 2;
offset = dx;
dx += len;
/* skip padding. */
while ( (dx & 0x03) != 0 && dx < buffer.size()) {
dx++;
}
if (type == STUN_ATTR_TYPE_FINGERPRINT) {
break;
}
type = 0;
len = 0;
}
/* rewrite message-length */
offset -= 16;
buffer[2] = (offset >> 8) & 0xFF;
buffer[3] = offset & 0xFF;
// result = (checksum::crc32LE(0 ^ 0xFFFFFFFF, (const char*)&buffer[0], offset + 12) ^ 0xFFFFFFFF) ^ 0x5354554e;
result = poly_crc32(0L, &buffer[0], offset + 12) ^ 0x5354554e;
/* and reset the size */
buffer[2] = curr_size[0];
buffer[3] = curr_size[1];
return 0;
}
/* --------------------------------------- */
StunAttribute::StunAttribute()
:type(STUN_ATTR_TYPE_NONE)
,length(0)
{
}
void StunAttribute::print() {
DONTEVEN_MSG("StunAttribute.type: %s", stun_attribute_type_to_string(type).c_str());
DONTEVEN_MSG("StunAttribute.length: %u", length);
switch (type) {
case STUN_ATTR_TYPE_XOR_MAPPED_ADDRESS: {
DONTEVEN_MSG("StunAttribute.xor_address.family: %s", stun_family_type_to_string(xor_address.family).c_str());
DONTEVEN_MSG("StunAttribute.xor_address.port: %u", xor_address.port);
DONTEVEN_MSG("StunAttribute.xor_address.ip: %s", (char*)xor_address.ip);
break;
}
case STUN_ATTR_TYPE_USERNAME: {
DONTEVEN_MSG("StunAttribute.username.value: `%.*s`", length, username.value);
break;
}
case STUN_ATTR_TYPE_SOFTWARE: {
DONTEVEN_MSG("StunAttribute.software.value: `%.*s`", length, software.value);
break;
}
case STUN_ATTR_TYPE_ICE_CONTROLLING: {
uint8_t* p = (uint8_t*)&ice_controlling.tie_breaker;
DONTEVEN_MSG("StunAttribute.ice_controlling.tie_breaker: 0x%04x%04x", *(uint32_t*)(p + 4), *(uint32_t*)(p));
break;
}
case STUN_ATTR_TYPE_PRIORITY: {
DONTEVEN_MSG("StunAttribute.priority.value: %u", priority.value);
break;
}
case STUN_ATTR_TYPE_MESSAGE_INTEGRITY: {
std::stringstream ss;
for(int i = 0; i < 20; ++i) {
ss << std::hex << (int) message_integrity.sha1[i];
}
std::string str = ss.str();
DONTEVEN_MSG("StunAttribute.message_integrity.sha1: %s", str.c_str());
break;
}
case STUN_ATTR_TYPE_FINGERPRINT: {
DONTEVEN_MSG("StunAttribute.fingerprint.value: 0x%08x", fingerprint.value);
break;
}
}
}
/* --------------------------------------- */
StunMessage::StunMessage()
:type(STUN_MSG_TYPE_NONE)
,length(0)
,cookie(0x2112a442)
{
transaction_id[0] = 0;
transaction_id[1] = 0;
transaction_id[2] = 0;
}
void StunMessage::setType(uint16_t messageType) {
type = messageType;
}
void StunMessage::setTransactionId(uint32_t a, uint32_t b, uint32_t c) {
transaction_id[0] = a;
transaction_id[1] = b;
transaction_id[2] = c;
}
void StunMessage::removeAttributes() {
attributes.clear();
}
void StunMessage::addAttribute(StunAttribute& attr) {
attributes.push_back(attr);
}
void StunMessage::print() {
DONTEVEN_MSG("StunMessage.type: %s", stun_message_type_to_string(type).c_str());
DONTEVEN_MSG("StunMessage.length: %u", length);
DONTEVEN_MSG("StunMessage.cookie: 0x%08X", cookie);
DONTEVEN_MSG("StunMessage.transaction_id: 0x%08X, 0x%08X, 0x%08X", transaction_id[0], transaction_id[1], transaction_id[2]);
}
StunAttribute* StunMessage::getAttributeByType(uint16_t type) {
size_t nattribs = attributes.size();
for (size_t i = 0; i < nattribs; ++i) {
if (attributes[i].type == type) {
return &attributes[i];
}
}
return NULL;
}
/* --------------------------------------- */
StunReader::StunReader()
:buffer_data(NULL)
,buffer_size(0)
,read_dx(0)
{
}
int StunReader::parse(uint8_t* data, size_t nbytes, size_t& nparsed, StunMessage& msg) {
StunAttribute attr;
size_t attr_offset = 0;
nparsed = 0;
if (NULL == data) {
FAIL_MSG("Cannot parse stun message because given data ptr is a NULL.");
return -1;
}
if (nbytes < 20) {
FAIL_MSG("Cannot parse stun message because given nbytes is < 20.");
return -2;
}
buffer_data = data;
buffer_size = nbytes;
read_dx = 0;
/* Read stun header. */
msg.type = readU16();
msg.length = readU16();
msg.cookie = readU32();
msg.transaction_id[0] = readU32();
msg.transaction_id[1] = readU32();
msg.transaction_id[2] = readU32();
if ((nbytes - 20) < msg.length) {
FAIL_MSG("Buffer is too small to contain the full stun message.");
return -3;
}
/* Read all the attributes. */
while ((read_dx + 4) < buffer_size) {
attr.type = readU16();
attr.length = readU16();
attr_offset = read_dx;
switch (attr.type) {
case STUN_ATTR_TYPE_USERNAME: {
if (0 != parseUsername(attr)) {
FAIL_MSG("Failed to read the username.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_XOR_MAPPED_ADDRESS: {
if (0 != parseXorMappedAddress(attr)) {
FAIL_MSG("Failed to read the xor-mapped-address.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_ICE_CONTROLLING: {
if (0 != parseIceControlling(attr)) {
FAIL_MSG("Failed to read the ice-contontrolling attribute.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_PRIORITY: {
if (0 != parsePriority(attr)) {
FAIL_MSG("Failed to read the priority attribute.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_MESSAGE_INTEGRITY: {
if (0 != parseMessageIntegrity(attr)) {
FAIL_MSG("Failed to parse the message integrity.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_FINGERPRINT: {
if (0 != parseFingerprint(attr)) {
FAIL_MSG("Failed to parse the fingerprint.");
return -4;
}
break;
}
case STUN_ATTR_TYPE_SOFTWARE: {
if (0 != parseSoftware(attr)) {
FAIL_MSG("Failed to parse the software attribute.");
return -4;
}
break;
}
default: {
DONTEVEN_MSG("Unhandled stun attribute: 0x%04X, %s", attr.type, stun_attribute_type_to_string(attr.type).c_str());
break;
}
}
/* Move the read_dx so it's positioned after the currently parsed attribute */
read_dx = attr_offset + attr.length;
while ( (read_dx & 0x03) != 0 && (read_dx < buffer_size)) {
read_dx++;
}
msg.attributes.push_back(attr);
attr.print();
}
nparsed = read_dx;
return 0;
}
/* --------------------------------------- */
int StunReader::parseFingerprint(StunAttribute& attr) {
if ((read_dx + 4) > buffer_size) {
FAIL_MSG("Cannot read FINGERPRINT because the buffer is too small.");
return -1;
}
attr.fingerprint.value = readU32();
return 0;
}
int StunReader::parseMessageIntegrity(StunAttribute& attr) {
if ((read_dx + 20) > buffer_size) {
FAIL_MSG("Cannot read the MESSAGE-INTEGRITY because the buffer is too small.");
return -1;
}
attr.message_integrity.sha1 = buffer_data + read_dx;
return 0;
}
int StunReader::parsePriority(StunAttribute& attr) {
if ((read_dx + 4) > buffer_size) {
FAIL_MSG("Cannot read the PRIORITY attribute because the buffer is too small.");
return -1;
}
attr.priority.value = readU32();
return 0;
}
int StunReader::parseSoftware(StunAttribute& attr) {
if ((read_dx + attr.length) > buffer_size) {
FAIL_MSG("Cannot read SOFTWARE attribute because the buffer is too small.");
return -1;
}
attr.software.value = (char*)(buffer_data + read_dx);
return 0;
}
int StunReader::parseIceControlling(StunAttribute& attr) {
if ((read_dx + 8) > buffer_size) {
FAIL_MSG("Cannot read the ICE-CONTROLLING attribute because the buffer is too small.");
return -1;
}
attr.ice_controlling.tie_breaker = readU64();
return 0;
}
int StunReader::parseUsername(StunAttribute& attr) {
if ((read_dx + attr.length) > buffer_size) {
FAIL_MSG("Cannot read USRENAME attribute because the buffer is too small.");
return -1;
}
attr.username.value = (char*)(buffer_data + read_dx);
return 0;
}
int StunReader::parseXorMappedAddress(StunAttribute& attr) {
if ( (read_dx + 8) > buffer_size) {
FAIL_MSG("Cannot read XOR_MAPPED_ADDRESS because the buffer is too small.");
return -1;
}
/* Skip the first byte, should be ignored by readers. */
read_dx++;
/* Read family */
attr.xor_address.family = readU8();
if (STUN_IP4 != attr.xor_address.family) {
FAIL_MSG("Currently we only implemented the IP4 XOR_MAPPED_ADDRESS");
return -2;
}
uint8_t cookie[] = { 0x42, 0xA4, 0x12, 0x21 };
uint32_t ip = 0;
uint8_t* ip_ptr = (uint8_t*) &ip;
uint8_t* port_ptr = (uint8_t*) &attr.xor_address.port;
/* Read the port. */
attr.xor_address.port = readU16();
port_ptr[0] = port_ptr[0] ^ cookie[2];
port_ptr[1] = port_ptr[1] ^ cookie[3];
/* Read IP4. */
ip = readU32();
ip_ptr[0] = ip_ptr[0] ^ cookie[0];
ip_ptr[1] = ip_ptr[1] ^ cookie[1];
ip_ptr[2] = ip_ptr[2] ^ cookie[2];
ip_ptr[3] = ip_ptr[3] ^ cookie[3];
sprintf((char*)attr.xor_address.ip,
"%u.%u.%u.%u",
ip_ptr[3],
ip_ptr[2],
ip_ptr[1],
ip_ptr[0]);
return 0;
}
/* --------------------------------------- */
uint8_t StunReader::readU8() {
if ( (read_dx + 1) > buffer_size) {
FAIL_MSG("Cannot readU8(), out of bounds.");
return 0;
}
uint8_t v = 0;
v = buffer_data[read_dx];
read_dx = read_dx + 1;
return v;
}
uint16_t StunReader::readU16() {
if ( (read_dx + 2) > buffer_size) {
FAIL_MSG("Cannot readU16(), out of bounds.");
return 0;
}
uint16_t v = 0;
uint8_t* p = (uint8_t*)&v;
p[0] = buffer_data[read_dx + 1];
p[1] = buffer_data[read_dx + 0];
read_dx = read_dx + 2;
return v;
}
uint32_t StunReader::readU32() {
if ( (read_dx + 4) > buffer_size) {
FAIL_MSG("Cannot readU32(), out of bounds.");
return 0;
}
uint32_t v = 0;
uint8_t* p = (uint8_t*)&v;
p[0] = buffer_data[read_dx + 3];
p[1] = buffer_data[read_dx + 2];
p[2] = buffer_data[read_dx + 1];
p[3] = buffer_data[read_dx + 0];
read_dx = read_dx + 4;
return v;
}
uint64_t StunReader::readU64() {
if ( (read_dx + 8) > buffer_size) {
FAIL_MSG("Cannot readU64(), out of bounds.");
return 0;
}
uint64_t v = 0;
uint8_t* p = (uint8_t*)&v;
p[0] = buffer_data[read_dx + 7];
p[1] = buffer_data[read_dx + 6];
p[2] = buffer_data[read_dx + 5];
p[3] = buffer_data[read_dx + 4];
p[4] = buffer_data[read_dx + 3];
p[5] = buffer_data[read_dx + 2];
p[6] = buffer_data[read_dx + 1];
p[7] = buffer_data[read_dx + 0];
read_dx = read_dx + 8;
return v;
}
/* --------------------------------------- */
StunWriter::StunWriter()
:padding_byte(0)
{
}
int StunWriter::begin(StunMessage& msg, uint8_t paddingByte) {
/* set the byte that we use when adding padding. */
padding_byte = paddingByte;
/* make sure we start with an empty buffer. */
buffer.clear();
/* writer header */
writeU16(msg.type); /* type */
writeU16(0); /* length */
writeU32(msg.cookie); /* magic cookie */
writeU32(msg.transaction_id[0]); /* transaction id */
writeU32(msg.transaction_id[1]); /* transaction id */
writeU32(msg.transaction_id[2]); /* transaction id */
return 0;
}
int StunWriter::end() {
if (buffer.size() < 20) {
FAIL_MSG("Cannot finalize the stun message because the header wasn't written.");
return -1;
}
rewriteU16(2, buffer.size() - 20);
return 0;
}
/* --------------------------------------- */
int StunWriter::writeXorMappedAddress(sockaddr_in addr) {
if (AF_INET != addr.sin_family) {
FAIL_MSG("Currently we only support ip4 xor-mapped-address attributes.");
return -1;
}
return writeXorMappedAddress(STUN_IP4, ntohs(addr.sin_port), ntohl(addr.sin_addr.s_addr));
}
int StunWriter::writeXorMappedAddress(uint8_t family, uint16_t port, const std::string& ip) {
uint32_t ip_int = 0;
if (0 != convertIp4StringToInt(ip, ip_int)) {
FAIL_MSG("Cannot write xor-mapped-address, because we failed to convert the given IP4 string into a uint32_t.");
return -1;
}
return writeXorMappedAddress(family, port, ip_int);
}
/* `ip` is in host byte order. */
int StunWriter::writeXorMappedAddress(uint8_t family, uint16_t port, uint32_t ip) {
if (buffer.size() < 20) {
FAIL_MSG("Cannot write the xor-mapped-address. Make sure you wrote the header first.");
return -1;
}
if (STUN_IP4 != family) {
FAIL_MSG("Cannot write the xor-mapped-address, we only support ip4 for now.");
return -2;
}
/* xor the port */
uint8_t cookie[] = { 0x42, 0xA4, 0x12, 0x21 };
uint8_t* port_ptr = (uint8_t*)&port;
port_ptr[0] = port_ptr[0] ^ cookie[2];
port_ptr[1] = port_ptr[1] ^ cookie[3];
/* xor the ip */
uint8_t* ip_ptr = (uint8_t*)&ip;
ip_ptr[0] = ip_ptr[0] ^ cookie[0];
ip_ptr[1] = ip_ptr[1] ^ cookie[1];
ip_ptr[2] = ip_ptr[2] ^ cookie[2];
ip_ptr[3] = ip_ptr[3] ^ cookie[3];
/* write header */
writeU16(STUN_ATTR_TYPE_XOR_MAPPED_ADDRESS);
writeU16(8);
writeU8(0);
writeU8(family);
/* port and ip */
writeU16(port);
writeU32(ip);
writePadding();
return 0;
}
int StunWriter::writeUsername(const std::string& username) {
if (buffer.size() < 20) {
FAIL_MSG("Cannot write username because you didn't call `begin()` and the STUN header hasn't been written yet..");
return -1;
}
writeU16(STUN_ATTR_TYPE_USERNAME);
writeU16(username.size());
writeString(username);
writePadding();
return 0;
}
int StunWriter::writeSoftware(const std::string& software) {
if (buffer.size() < 20) {
FAIL_MSG("Cannot write software because it seems that you didn't call `begin()` which writes the stun header.");
return -1;
}
if (software.size() > 763) {
FAIL_MSG("Given software length is too big. ");
return -2;
}
writeU16(STUN_ATTR_TYPE_SOFTWARE);
writeU16(software.size());
writeString(software);
writePadding();
return 0;
}
int StunWriter::writeMessageIntegrity(const std::string& password) {
if (buffer.size() < 20) {
FAIL_MSG("Cannot write the message integrity because it seems that you didn't call `begin()` which writes the stun header.");
return -1;
}
if (0 == password.size()) {
FAIL_MSG("The password is empty, cannot write the message integrity.");
return -2;
}
writeU16(STUN_ATTR_TYPE_MESSAGE_INTEGRITY);
writeU16(20);
/* calculate the sha1 over the current buffer. */
uint8_t sha1[20] = {};
if (0 != stun_compute_message_integrity(buffer, password, sha1)) {
FAIL_MSG("Failed to write the message integrity.");
return -3;
}
/* store the message-integrity */
std::copy(sha1, sha1 + 20, std::back_inserter(buffer));
writePadding();
return 0;
}
/* https://tools.ietf.org/html/rfc5389#section-15.5 */
int StunWriter::writeFingerprint() {
if (buffer.size() < 20) {
FAIL_MSG("Cannot write the fingerprint because it seems that you didn't write the header, call `begin()` first.");
return -1;
}
writeU16(STUN_ATTR_TYPE_FINGERPRINT);
writeU16(4);
uint32_t fingerprint = 0;
if (0 != stun_compute_fingerprint(buffer, fingerprint)) {
FAIL_MSG("Failed to compute the fingerprint.");
return -2;
}
writeU32(fingerprint);
writePadding();
return 0;
}
/* --------------------------------------- */
int StunWriter::convertIp4StringToInt(const std::string& ip, uint32_t& result) {
if (0 == ip.size()) {
FAIL_MSG("Given ip string is empty.");
return -1;
}
in_addr addr;
if (1 != inet_pton(AF_INET, ip.c_str(), &addr)) {
FAIL_MSG("inet_pton() failed, cannot convert ip4 string into uint32_t.");
return -2;
}
result = ntohl(addr.s_addr);
return 0;
}
/* --------------------------------------- */
void StunWriter::writeU8(uint8_t v) {
buffer.push_back(v);
}
void StunWriter::writeU16(uint16_t v) {
uint8_t* p = (uint8_t*)&v;
buffer.push_back(p[1]);
buffer.push_back(p[0]);
}
void StunWriter::writeU32(uint32_t v) {
uint8_t* p = (uint8_t*)&v;
buffer.push_back(p[3]);
buffer.push_back(p[2]);
buffer.push_back(p[1]);
buffer.push_back(p[0]);
}
void StunWriter::writeU64(uint64_t v) {
uint8_t* p = (uint8_t*)&v;
buffer.push_back(p[7]);
buffer.push_back(p[6]);
buffer.push_back(p[5]);
buffer.push_back(p[4]);
buffer.push_back(p[3]);
buffer.push_back(p[2]);
buffer.push_back(p[1]);
buffer.push_back(p[0]);
}
void StunWriter::rewriteU16(size_t dx, uint16_t v) {
if ((dx + 2) > buffer.size()) {
FAIL_MSG("Trying to rewriteU16, but our buffer is too small to contain a u16.");
return;
}
uint8_t* p = (uint8_t*) &v;
buffer[dx + 0] = p[1];
buffer[dx + 1] = p[0];
}
void StunWriter::rewriteU32(size_t dx, uint32_t v) {
if ((dx + 4) > buffer.size()) {
FAIL_MSG("Trying to rewrite U32 in Stun::StunWriter::rewriteU32() but index is out of bounds.\n");
return;
}
uint8_t* p = (uint8_t*)&v;
buffer[dx + 0] = p[3];
buffer[dx + 1] = p[2];
buffer[dx + 2] = p[1];
buffer[dx + 3] = p[0];
}
void StunWriter::writeString(const std::string& str) {
std::copy(str.begin(), str.end(), std::back_inserter(buffer));
}
void StunWriter::writePadding() {
while ((buffer.size() & 0x03) != 0) {
buffer.push_back(padding_byte);
}
}
/* --------------------------------------- */
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