2020-10-10 12:00:26 -05:00

300 lines
8.9 KiB
C++

#define _CRT_RAND_S
#define _CRT_SECURE_NO_WARNINGS
#include <stdlib.h>
#define WIN32_LEAN_AND_MEAN
#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <Windows.h>
#include <WinSock2.h>
#include <WS2tcpip.h>
#pragma comment(lib, "Shlwapi.lib")
#include <shlwapi.h>
#include <assert.h>
#include <stdio.h>
#define RECV_TIMEOUT_SEC 3
#define PCP_VERSION 2
#define OPCODE_MAP_REQUEST 0x01
#define OPCODE_MAP_RESPONSE 0x81
#define CODE_PREFER_FAILURE 2
#pragma pack(push, 1)
typedef struct _PCP_REQUEST_HEADER {
unsigned char version;
unsigned char opcode;
unsigned short reserved;
unsigned int lifetime;
unsigned char localAddress[16];
} PCP_REQUEST_HEADER, *PPCP_REQUEST_HEADER;
typedef struct _PCP_RESPONSE_HEADER {
unsigned char version;
unsigned char opcode;
unsigned char reserved;
unsigned char result;
unsigned int lifetime;
unsigned int epoch;
unsigned char reserved2[12];
} PCP_RESPONSE_HEADER, *PPCP_RESPONSE_HEADER;
typedef struct _PCP_OPTION_HEADER {
unsigned char code;
unsigned char reserved;
unsigned short length;
} PCP_OPTION_HEADER, *PPCP_OPTION_HEADER;
typedef struct _PCP_MAP_REQUEST {
PCP_REQUEST_HEADER hdr;
unsigned char mappingNonce[12];
unsigned char protocol;
unsigned char reserved[3];
unsigned short internalPort;
unsigned short externalPort;
unsigned char externalAddress[16];
// We send PREFER_FAILURE too for MAP requests
PCP_OPTION_HEADER preferFailureOption;
} PCP_MAP_REQUEST, *PPCP_MAP_REQUEST;
typedef struct _PCP_MAP_RESPONSE {
PCP_RESPONSE_HEADER hdr;
unsigned char mappingNonce[12];
unsigned char protocol;
unsigned char reserved[3];
unsigned short internalPort;
unsigned short externalPort;
unsigned char externalAddress[16];
} PCP_MAP_RESPONSE, *PPCP_MAP_RESPONSE;
#pragma pack(pop)
static void populateMappingNonce(PPCP_MAP_REQUEST request, PSOCKADDR_STORAGE pcpAddr, int pcpAddrLen)
{
struct {
unsigned short port;
unsigned char localAddress[16];
SOCKADDR_STORAGE targetAddress;
} dataToHash;
assert(request->internalPort != 0);
dataToHash.port = request->internalPort;
memcpy(dataToHash.localAddress, request->hdr.localAddress, sizeof(dataToHash.localAddress));
memcpy(&dataToHash.targetAddress, pcpAddr, pcpAddrLen);
HashData((BYTE*)&dataToHash, 18 + pcpAddrLen, request->mappingNonce, sizeof(request->mappingNonce));
}
static void populateAddressFromSockAddr(PSOCKADDR_STORAGE sockAddr, unsigned char* address)
{
if (sockAddr->ss_family == AF_INET) {
PSOCKADDR_IN sin = (PSOCKADDR_IN)sockAddr;
memset(&address[0], 0, 10);
memset(&address[10], 0xFF, 2);
memcpy(&address[12], &sin->sin_addr, 4);
}
else if (sockAddr->ss_family == AF_INET6) {
PSOCKADDR_IN6 sin6 = (PSOCKADDR_IN6)sockAddr;
memcpy(address, &sin6->sin6_addr, 16);
}
else {
assert(false);
}
}
bool PCPMapPort(PSOCKADDR_STORAGE localAddr, int localAddrLen, PSOCKADDR_STORAGE pcpAddr, int pcpAddrLen, int proto, int port, bool enable, bool indefinite)
{
SOCKET sock;
PCP_MAP_REQUEST reqMsg;
int reqMsgLen;
int i;
int bytesRead;
union {
PCP_MAP_RESPONSE hdr;
char buf[1100];
} resp;
int lifetime;
if (!enable) {
lifetime = 0;
}
else if (indefinite) {
lifetime = 604800; // 1 week
}
else {
lifetime = 3600;
}
assert(localAddr->ss_family == pcpAddr->ss_family);
printf("Updating PCP port mapping for %s %d...", proto == IPPROTO_TCP ? "TCP" : "UDP", port);
sock = socket(localAddr->ss_family, SOCK_DGRAM, IPPROTO_UDP);
if (sock == INVALID_SOCKET) {
printf("socket() failed: %d\n", WSAGetLastError());
return false;
}
if (localAddr->ss_family == AF_INET6) {
// Make sure we're sourcing from the correct IPv6 address to ensure the port
// is opened correctly and that the PCP server doesn't refuse our mapping.
((PSOCKADDR_IN6)localAddr)->sin6_port = 0;
if (bind(sock, (struct sockaddr*)localAddr, localAddrLen) == SOCKET_ERROR) {
printf("bind() failed: %d\n", WSAGetLastError());
closesocket(sock);
return false;
}
}
((PSOCKADDR_IN)pcpAddr)->sin_port = htons(5351);
if (connect(sock, (struct sockaddr*)pcpAddr, pcpAddrLen) == SOCKET_ERROR) {
printf("connect() failed: %d\n", WSAGetLastError());
closesocket(sock);
return false;
}
reqMsg = {};
reqMsg.hdr.version = PCP_VERSION;
reqMsg.hdr.opcode = OPCODE_MAP_REQUEST;
reqMsg.hdr.lifetime = htonl(lifetime);
populateAddressFromSockAddr(localAddr, reqMsg.hdr.localAddress);
reqMsg.protocol = proto;
reqMsg.internalPort = htons(port);
reqMsg.externalPort = htons(port);
SOCKADDR_STORAGE noneAddr = {};
noneAddr.ss_family = localAddr->ss_family;
populateAddressFromSockAddr(&noneAddr, reqMsg.externalAddress);
if (enable) {
// We don't want an alternate allocation if this fails
reqMsg.preferFailureOption.code = CODE_PREFER_FAILURE;
reqMsg.preferFailureOption.length = 0;
reqMsgLen = sizeof(reqMsg);
}
else {
// We don't append PREFER_FAILURE for an unmap request
reqMsgLen = sizeof(reqMsg) - sizeof(reqMsg.preferFailureOption);
}
// This must be done after the rest of the message is populated
populateMappingNonce(&reqMsg, pcpAddr, pcpAddrLen);
bytesRead = 0;
for (i = 0; i < RECV_TIMEOUT_SEC; i++) {
// Retransmit the request every second until the timeout elapses
if (send(sock, (char *)&reqMsg, reqMsgLen, 0) == SOCKET_ERROR) {
printf("send() failed: %d\n", WSAGetLastError());
closesocket(sock);
return false;
}
fd_set fds;
FD_ZERO(&fds);
FD_SET(sock, &fds);
struct timeval tv;
tv.tv_sec = 1;
tv.tv_usec = 0;
int selectRes = select(0, &fds, nullptr, nullptr, &tv);
if (selectRes == 0) {
// Timeout - continue looping
continue;
}
else if (selectRes == SOCKET_ERROR) {
printf("select() failed: %d\n", WSAGetLastError());
closesocket(sock);
return false;
}
// Error handling is below
bytesRead = recv(sock, resp.buf, sizeof(resp.buf), 0);
break;
}
if (bytesRead == 0) {
printf("NO RESPONSE\n");
goto fail;
}
else if (bytesRead == SOCKET_ERROR) {
printf("Failed to read PCP response: %d\n", WSAGetLastError());
goto fail;
}
else if (bytesRead < sizeof(resp.hdr)) {
printf("PCP message truncated: %d\n", bytesRead);
goto fail;
}
else if (resp.hdr.hdr.version != PCP_VERSION) {
printf("PCP version mismatch: %x\n", resp.hdr.hdr.version);
goto fail;
}
else if (resp.hdr.hdr.opcode != OPCODE_MAP_RESPONSE) {
printf("PCP message type mismatch: %x\n", resp.hdr.hdr.opcode);
goto fail;
}
else if (resp.hdr.hdr.result != 0) {
switch (resp.hdr.hdr.result) {
case 1: // UNSUPP_VERSION
printf("UNSUPPORTED\n");
break;
case 2: // NOT_AUTHORIZED
printf("UNAUTHORIZED\n");
break;
case 11: // CANNOT_PROVIDE_EXTERNAL
printf("CONFLICT\n");
break;
default:
printf("ERROR: %d\n", resp.hdr.hdr.result);
break;
}
goto fail;
}
else if (memcmp(reqMsg.mappingNonce, resp.hdr.mappingNonce, sizeof(reqMsg.mappingNonce))) {
printf("PCP mapping nonce mismatch\n");
goto fail;
}
else if (reqMsg.protocol != resp.hdr.protocol) {
printf("PCP protocol mismatch: %d wanted %d\n", resp.hdr.protocol, reqMsg.protocol);
goto fail;
}
else if (reqMsg.internalPort != resp.hdr.internalPort) {
printf("PCP internal port mismatch: %d wanted %d\n", htons(resp.hdr.internalPort), htons(reqMsg.internalPort));
goto fail;
}
else if (reqMsg.externalPort != resp.hdr.externalPort) {
printf("PCP returned different external port: %d wanted %d\n", htons(resp.hdr.externalPort), htons(reqMsg.externalPort));
if (enable) {
// Clear the port mapping by modifying and resending the old request (with the same nonce)
reqMsg.hdr.lifetime = 0;
reqMsg.externalPort = resp.hdr.externalPort;
reqMsgLen = sizeof(reqMsg) - sizeof(reqMsg.preferFailureOption);
if (send(sock, (char*)&reqMsg, reqMsgLen, 0) == SOCKET_ERROR) {
printf("Failed to unmap unexpected external port: %d\n", WSAGetLastError());
}
}
goto fail;
}
if (enable) {
printf("OK (%d seconds remaining)\n", ntohl(resp.hdr.hdr.lifetime));
}
else {
printf("DELETED\n");
}
closesocket(sock);
return true;
fail:
closesocket(sock);
return false;
}