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i2pd/SOCKS.cpp

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#include <cstring>
#include <cassert>
#include <string>
#include <atomic>
#include "SOCKS.h"
#include "Identity.h"
#include "Streaming.h"
#include "Destination.h"
#include "ClientContext.h"
#include "I2PEndian.h"
#include "I2PTunnel.h"
#include "I2PService.h"
namespace i2p
{
namespace proxy
{
static const size_t socks_buffer_size = 8192;
static const size_t max_socks_hostname_size = 255; // Limit for socks5 and bad idea to traverse
static const size_t SOCKS_FORWARDER_BUFFER_SIZE = 8192;
static const size_t SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE = 8;
struct SOCKSDnsAddress
{
uint8_t size;
char value[max_socks_hostname_size];
void FromString (std::string str)
{
size = str.length();
if (str.length() > max_socks_hostname_size) size = max_socks_hostname_size;
memcpy(value,str.c_str(),size);
}
std::string ToString() { return std::string(value, size); }
void push_back (char c) { value[size++] = c; }
};
class SOCKSServer;
class SOCKSHandler: public i2p::client::I2PServiceHandler, public std::enable_shared_from_this<SOCKSHandler>
{
private:
enum state
{
GET_SOCKSV,
GET_COMMAND,
GET_PORT,
GET_IPV4,
GET4_IDENT,
GET4A_HOST,
GET5_AUTHNUM,
GET5_AUTH,
GET5_REQUESTV,
GET5_GETRSV,
GET5_GETADDRTYPE,
GET5_IPV6,
GET5_HOST_SIZE,
GET5_HOST,
READY,
UPSTREAM_RESOLVE,
UPSTREAM_CONNECT,
UPSTREAM_HANDSHAKE
};
enum authMethods
{
AUTH_NONE = 0, //No authentication, skip to next step
AUTH_GSSAPI = 1, //GSSAPI authentication
AUTH_USERPASSWD = 2, //Username and password
AUTH_UNACCEPTABLE = 0xff //No acceptable method found
};
enum addrTypes
{
ADDR_IPV4 = 1, //IPv4 address (4 octets)
ADDR_DNS = 3, // DNS name (up to 255 octets)
ADDR_IPV6 = 4 //IPV6 address (16 octets)
};
enum errTypes
{
SOCKS5_OK = 0, // No error for SOCKS5
SOCKS5_GEN_FAIL = 1, // General server failure
SOCKS5_RULE_DENIED = 2, // Connection disallowed by ruleset
SOCKS5_NET_UNREACH = 3, // Network unreachable
SOCKS5_HOST_UNREACH = 4, // Host unreachable
SOCKS5_CONN_REFUSED = 5, // Connection refused by the peer
SOCKS5_TTL_EXPIRED = 6, // TTL Expired
SOCKS5_CMD_UNSUP = 7, // Command unsuported
SOCKS5_ADDR_UNSUP = 8, // Address type unsuported
SOCKS4_OK = 90, // No error for SOCKS4
SOCKS4_FAIL = 91, // Failed establishing connecting or not allowed
SOCKS4_IDENTD_MISSING = 92, // Couldn't connect to the identd server
SOCKS4_IDENTD_DIFFER = 93 // The ID reported by the application and by identd differ
};
enum cmdTypes
{
CMD_CONNECT = 1, // TCP Connect
CMD_BIND = 2, // TCP Bind
CMD_UDP = 3 // UDP associate
};
enum socksVersions
{
SOCKS4 = 4, // SOCKS4
SOCKS5 = 5 // SOCKS5
};
union address
{
uint32_t ip;
SOCKSDnsAddress dns;
uint8_t ipv6[16];
};
void EnterState(state nstate, uint8_t parseleft = 1);
bool HandleData(uint8_t *sock_buff, std::size_t len);
bool ValidateSOCKSRequest();
void HandleSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered);
void Terminate();
void AsyncSockRead();
boost::asio::const_buffers_1 GenerateSOCKS5SelectAuth(authMethods method);
boost::asio::const_buffers_1 GenerateSOCKS4Response(errTypes error, uint32_t ip, uint16_t port);
boost::asio::const_buffers_1 GenerateSOCKS5Response(errTypes error, addrTypes type, const address &addr, uint16_t port);
boost::asio::const_buffers_1 GenerateUpstreamRequest();
bool Socks5ChooseAuth();
void SocksRequestFailed(errTypes error);
void SocksRequestSuccess();
void SentSocksFailed(const boost::system::error_code & ecode);
void SentSocksDone(const boost::system::error_code & ecode);
void SentSocksResponse(const boost::system::error_code & ecode);
void HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream);
void ForwardSOCKS();
void SocksUpstreamSuccess();
void AsyncUpstreamSockRead();
void SendUpstreamRequest();
void HandleUpstreamData(uint8_t * buff, std::size_t len);
void HandleUpstreamSockSend(const boost::system::error_code & ecode, std::size_t bytes_transfered);
void HandleUpstreamSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered);
void HandleUpstreamConnected(const boost::system::error_code & ecode,
boost::asio::ip::tcp::resolver::iterator itr);
void HandleUpstreamResolved(const boost::system::error_code & ecode,
boost::asio::ip::tcp::resolver::iterator itr);
boost::asio::ip::tcp::resolver m_proxy_resolver;
uint8_t m_sock_buff[socks_buffer_size];
std::shared_ptr<boost::asio::ip::tcp::socket> m_sock, m_upstreamSock;
std::shared_ptr<i2p::stream::Stream> m_stream;
uint8_t *m_remaining_data; //Data left to be sent
uint8_t *m_remaining_upstream_data; //upstream data left to be forwarded
uint8_t m_response[7+max_socks_hostname_size];
uint8_t m_upstream_response[SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE];
uint8_t m_upstream_request[14+max_socks_hostname_size];
std::size_t m_upstream_response_len;
address m_address; //Address
std::size_t m_remaining_data_len; //Size of the data left to be sent
uint32_t m_4aip; //Used in 4a requests
uint16_t m_port;
uint8_t m_command;
uint8_t m_parseleft; //Octets left to parse
authMethods m_authchosen; //Authentication chosen
addrTypes m_addrtype; //Address type chosen
socksVersions m_socksv; //Socks version
cmdTypes m_cmd; // Command requested
state m_state;
const bool m_UseUpstreamProxy; // do we want to use the upstream proxy for non i2p addresses?
const std::string m_UpstreamProxyAddress;
const uint16_t m_UpstreamProxyPort;
public:
SOCKSHandler(SOCKSServer * parent, std::shared_ptr<boost::asio::ip::tcp::socket> sock, const std::string & upstreamAddr, const uint16_t upstreamPort, const bool useUpstream) :
I2PServiceHandler(parent),
m_proxy_resolver(parent->GetService()),
m_sock(sock), m_stream(nullptr),
m_authchosen(AUTH_UNACCEPTABLE), m_addrtype(ADDR_IPV4),
m_UseUpstreamProxy(useUpstream),
m_UpstreamProxyAddress(upstreamAddr),
m_UpstreamProxyPort(upstreamPort)
{ m_address.ip = 0; EnterState(GET_SOCKSV); }
~SOCKSHandler() { Terminate(); }
void Handle() { AsyncSockRead(); }
};
void SOCKSHandler::AsyncSockRead()
{
LogPrint(eLogDebug, "SOCKS: async sock read");
if (m_sock) {
m_sock->async_receive(boost::asio::buffer(m_sock_buff, socks_buffer_size),
std::bind(&SOCKSHandler::HandleSockRecv, shared_from_this(),
std::placeholders::_1, std::placeholders::_2));
} else {
LogPrint(eLogError,"SOCKS: no socket for read");
}
}
void SOCKSHandler::Terminate()
{
if (Kill()) return;
if (m_sock)
{
LogPrint(eLogDebug, "SOCKS: closing socket");
m_sock->close();
m_sock = nullptr;
}
if (m_upstreamSock)
{
LogPrint(eLogDebug, "SOCKS: closing upstream socket");
m_upstreamSock->close();
m_upstreamSock = nullptr;
}
if (m_stream)
{
LogPrint(eLogDebug, "SOCKS: closing stream");
m_stream.reset ();
}
Done(shared_from_this());
}
boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS4Response(SOCKSHandler::errTypes error, uint32_t ip, uint16_t port)
{
assert(error >= SOCKS4_OK);
m_response[0] = '\x00'; //Version
m_response[1] = error; //Response code
htobe16buf(m_response+2,port); //Port
htobe32buf(m_response+4,ip); //IP
return boost::asio::const_buffers_1(m_response,8);
}
boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS5Response(SOCKSHandler::errTypes error, SOCKSHandler::addrTypes type, const SOCKSHandler::address &addr, uint16_t port)
{
size_t size = 6;
assert(error <= SOCKS5_ADDR_UNSUP);
m_response[0] = '\x05'; //Version
m_response[1] = error; //Response code
m_response[2] = '\x00'; //RSV
m_response[3] = type; //Address type
switch (type)
{
case ADDR_IPV4:
size = 10;
htobe32buf(m_response+4,addr.ip);
break;
case ADDR_IPV6:
size = 22;
memcpy(m_response+4,addr.ipv6, 16);
break;
case ADDR_DNS:
size = 7+addr.dns.size;
m_response[4] = addr.dns.size;
memcpy(m_response+5,addr.dns.value, addr.dns.size);
break;
}
htobe16buf(m_response+size-2,port); //Port
return boost::asio::const_buffers_1(m_response,size);
}
boost::asio::const_buffers_1 SOCKSHandler::GenerateUpstreamRequest()
{
size_t upstreamRequestSize = 0;
// TODO: negotiate with upstream
// SOCKS 4a
m_upstream_request[0] = '\x04'; //version
m_upstream_request[1] = m_cmd;
htobe16buf(m_upstream_request+2, m_port);
m_upstream_request[4] = 0;
m_upstream_request[5] = 0;
m_upstream_request[6] = 0;
m_upstream_request[7] = 1;
// user id
m_upstream_request[8] = 'i';
m_upstream_request[9] = '2';
m_upstream_request[10] = 'p';
m_upstream_request[11] = 'd';
m_upstream_request[12] = 0;
upstreamRequestSize += 13;
if (m_address.dns.size <= max_socks_hostname_size - ( upstreamRequestSize + 1) ) {
// bounds check okay
memcpy(m_upstream_request + upstreamRequestSize, m_address.dns.value, m_address.dns.size);
upstreamRequestSize += m_address.dns.size;
// null terminate
m_upstream_request[++upstreamRequestSize] = 0;
} else {
LogPrint(eLogError, "SOCKS: BUG!!! m_addr.dns.sizs > max_socks_hostname - ( upstreamRequestSize + 1 ) )");
}
return boost::asio::const_buffers_1(m_upstream_request, upstreamRequestSize);
}
bool SOCKSHandler::Socks5ChooseAuth()
{
m_response[0] = '\x05'; //Version
m_response[1] = m_authchosen; //Response code
boost::asio::const_buffers_1 response(m_response,2);
if (m_authchosen == AUTH_UNACCEPTABLE)
{
LogPrint(eLogWarning, "SOCKS: v5 authentication negotiation failed");
boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed,
shared_from_this(), std::placeholders::_1));
return false;
}
else
{
LogPrint(eLogDebug, "SOCKS: v5 choosing authentication method: ", m_authchosen);
boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksResponse,
shared_from_this(), std::placeholders::_1));
return true;
}
}
/* All hope is lost beyond this point */
void SOCKSHandler::SocksRequestFailed(SOCKSHandler::errTypes error)
{
boost::asio::const_buffers_1 response(nullptr,0);
assert(error != SOCKS4_OK && error != SOCKS5_OK);
switch (m_socksv)
{
case SOCKS4:
LogPrint(eLogWarning, "SOCKS: v4 request failed: ", error);
if (error < SOCKS4_OK) error = SOCKS4_FAIL; //Transparently map SOCKS5 errors
response = GenerateSOCKS4Response(error, m_4aip, m_port);
break;
case SOCKS5:
LogPrint(eLogWarning, "SOCKS: v5 request failed: ", error);
response = GenerateSOCKS5Response(error, m_addrtype, m_address, m_port);
break;
}
boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed,
shared_from_this(), std::placeholders::_1));
}
void SOCKSHandler::SocksRequestSuccess()
{
boost::asio::const_buffers_1 response(nullptr,0);
//TODO: this should depend on things like the command type and callbacks may change
switch (m_socksv)
{
case SOCKS4:
LogPrint(eLogInfo, "SOCKS: v4 connection success");
response = GenerateSOCKS4Response(SOCKS4_OK, m_4aip, m_port);
break;
case SOCKS5:
LogPrint(eLogInfo, "SOCKS: v5 connection success");
auto s = i2p::client::context.GetAddressBook().ToAddress(GetOwner()->GetLocalDestination()->GetIdentHash());
address ad; ad.dns.FromString(s);
//HACK only 16 bits passed in port as SOCKS5 doesn't allow for more
response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, ad, m_stream->GetRecvStreamID());
break;
}
boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksDone,
shared_from_this(), std::placeholders::_1));
}
void SOCKSHandler::EnterState(SOCKSHandler::state nstate, uint8_t parseleft) {
switch (nstate)
{
case GET_PORT: parseleft = 2; break;
case GET_IPV4: m_addrtype = ADDR_IPV4; m_address.ip = 0; parseleft = 4; break;
case GET4_IDENT: m_4aip = m_address.ip; break;
case GET4A_HOST:
case GET5_HOST: m_addrtype = ADDR_DNS; m_address.dns.size = 0; break;
case GET5_IPV6: m_addrtype = ADDR_IPV6; parseleft = 16; break;
default:;
}
m_parseleft = parseleft;
m_state = nstate;
}
bool SOCKSHandler::ValidateSOCKSRequest()
{
if ( m_cmd != CMD_CONNECT )
{
//TODO: we need to support binds and other shit!
LogPrint(eLogError, "SOCKS: unsupported command: ", m_cmd);
SocksRequestFailed(SOCKS5_CMD_UNSUP);
return false;
}
//TODO: we may want to support other address types!
if ( m_addrtype != ADDR_DNS )
{
switch (m_socksv)
{
case SOCKS5:
LogPrint(eLogError, "SOCKS: v5 unsupported address type: ", m_addrtype);
break;
case SOCKS4:
LogPrint(eLogError, "SOCKS: request with v4a rejected because it's actually SOCKS4");
break;
}
SocksRequestFailed(SOCKS5_ADDR_UNSUP);
return false;
}
return true;
}
bool SOCKSHandler::HandleData(uint8_t *sock_buff, std::size_t len)
{
assert(len); // This should always be called with a least a byte left to parse
while (len > 0)
{
switch (m_state)
{
case GET_SOCKSV:
m_socksv = (SOCKSHandler::socksVersions) *sock_buff;
switch (*sock_buff)
{
case SOCKS4:
EnterState(GET_COMMAND); //Initialize the parser at the right position
break;
case SOCKS5:
EnterState(GET5_AUTHNUM); //Initialize the parser at the right position
break;
default:
LogPrint(eLogError, "SOCKS: rejected invalid version: ", ((int)*sock_buff));
Terminate();
return false;
}
break;
case GET5_AUTHNUM:
EnterState(GET5_AUTH, *sock_buff);
break;
case GET5_AUTH:
m_parseleft --;
if (*sock_buff == AUTH_NONE)
m_authchosen = AUTH_NONE;
if ( m_parseleft == 0 )
{
if (!Socks5ChooseAuth()) return false;
EnterState(GET5_REQUESTV);
}
break;
case GET_COMMAND:
switch (*sock_buff)
{
case CMD_CONNECT:
case CMD_BIND:
break;
case CMD_UDP:
if (m_socksv == SOCKS5) break;
default:
LogPrint(eLogError, "SOCKS: invalid command: ", ((int)*sock_buff));
SocksRequestFailed(SOCKS5_GEN_FAIL);
return false;
}
m_cmd = (SOCKSHandler::cmdTypes)*sock_buff;
switch (m_socksv)
{
case SOCKS5: EnterState(GET5_GETRSV); break;
case SOCKS4: EnterState(GET_PORT); break;
}
break;
case GET_PORT:
m_port = (m_port << 8)|((uint16_t)*sock_buff);
m_parseleft--;
if (m_parseleft == 0)
{
switch (m_socksv)
{
case SOCKS5: EnterState(READY); break;
case SOCKS4: EnterState(GET_IPV4); break;
}
}
break;
case GET_IPV4:
m_address.ip = (m_address.ip << 8)|((uint32_t)*sock_buff);
m_parseleft--;
if (m_parseleft == 0)
{
switch (m_socksv)
{
case SOCKS5: EnterState(GET_PORT); break;
case SOCKS4: EnterState(GET4_IDENT); m_4aip = m_address.ip; break;
}
}
break;
case GET4_IDENT:
if (!*sock_buff)
{
if( m_4aip == 0 || m_4aip > 255 )
EnterState(READY);
else
EnterState(GET4A_HOST);
}
break;
case GET4A_HOST:
if (!*sock_buff)
{
EnterState(READY);
break;
}
if (m_address.dns.size >= max_socks_hostname_size)
{
LogPrint(eLogError, "SOCKS: v4a req failed: destination is too large");
SocksRequestFailed(SOCKS4_FAIL);
return false;
}
m_address.dns.push_back(*sock_buff);
break;
case GET5_REQUESTV:
if (*sock_buff != SOCKS5)
{
LogPrint(eLogError,"SOCKS: v5 rejected unknown request version: ", ((int)*sock_buff));
SocksRequestFailed(SOCKS5_GEN_FAIL);
return false;
}
EnterState(GET_COMMAND);
break;
case GET5_GETRSV:
if ( *sock_buff != 0 )
{
LogPrint(eLogError, "SOCKS: v5 unknown reserved field: ", ((int)*sock_buff));
SocksRequestFailed(SOCKS5_GEN_FAIL);
return false;
}
EnterState(GET5_GETADDRTYPE);
break;
case GET5_GETADDRTYPE:
switch (*sock_buff)
{
case ADDR_IPV4: EnterState(GET_IPV4); break;
case ADDR_IPV6: EnterState(GET5_IPV6); break;
case ADDR_DNS : EnterState(GET5_HOST_SIZE); break;
default:
LogPrint(eLogError, "SOCKS: v5 unknown address type: ", ((int)*sock_buff));
SocksRequestFailed(SOCKS5_GEN_FAIL);
return false;
}
break;
case GET5_IPV6:
m_address.ipv6[16-m_parseleft] = *sock_buff;
m_parseleft--;
if (m_parseleft == 0) EnterState(GET_PORT);
break;
case GET5_HOST_SIZE:
EnterState(GET5_HOST, *sock_buff);
break;
case GET5_HOST:
m_address.dns.push_back(*sock_buff);
m_parseleft--;
if (m_parseleft == 0) EnterState(GET_PORT);
break;
default:
LogPrint(eLogError, "SOCKS: parse state?? ", m_state);
Terminate();
return false;
}
sock_buff++;
len--;
if (m_state == READY)
{
m_remaining_data_len = len;
m_remaining_data = sock_buff;
return ValidateSOCKSRequest();
}
}
return true;
}
void SOCKSHandler::HandleSockRecv(const boost::system::error_code & ecode, std::size_t len)
{
LogPrint(eLogDebug, "SOCKS: recieved ", len, " bytes");
if(ecode)
{
LogPrint(eLogWarning, "SOCKS: recv got error: ", ecode);
Terminate();
return;
}
if (HandleData(m_sock_buff, len))
{
if (m_state == READY)
{
const std::string addr = m_address.dns.ToString();
LogPrint(eLogInfo, "SOCKS: requested ", addr, ":" , m_port);
const size_t addrlen = addr.size();
// does it end with .i2p?
if ( addr.rfind(".i2p") == addrlen - 4) {
// yes it does, make an i2p session
GetOwner()->CreateStream ( std::bind (&SOCKSHandler::HandleStreamRequestComplete,
shared_from_this(), std::placeholders::_1), m_address.dns.ToString(), m_port);
} else if (m_UseUpstreamProxy) {
// forward it to upstream proxy
ForwardSOCKS();
} else {
// no upstream proxy
SocksRequestFailed(SOCKS5_ADDR_UNSUP);
}
}
else
AsyncSockRead();
}
}
void SOCKSHandler::SentSocksFailed(const boost::system::error_code & ecode)
{
if (ecode)
LogPrint (eLogError, "SOCKS: closing socket after sending failure because: ", ecode.message ());
Terminate();
}
void SOCKSHandler::SentSocksDone(const boost::system::error_code & ecode)
{
if (!ecode)
{
if (Kill()) return;
LogPrint (eLogInfo, "SOCKS: new I2PTunnel connection");
auto connection = std::make_shared<i2p::client::I2PTunnelConnection>(GetOwner(), m_sock, m_stream);
GetOwner()->AddHandler (connection);
connection->I2PConnect (m_remaining_data,m_remaining_data_len);
Done(shared_from_this());
}
else
{
LogPrint (eLogError, "SOCKS: closing socket after completion reply because: ", ecode.message ());
Terminate();
}
}
void SOCKSHandler::SentSocksResponse(const boost::system::error_code & ecode)
{
if (ecode)
{
LogPrint (eLogError, "SOCKS: closing socket after sending reply because: ", ecode.message ());
Terminate();
}
}
void SOCKSHandler::HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream)
{
if (stream)
{
m_stream = stream;
SocksRequestSuccess();
}
else
{
LogPrint (eLogError, "SOCKS: error when creating the stream, check the previous warnings for more info");
SocksRequestFailed(SOCKS5_HOST_UNREACH);
}
}
void SOCKSHandler::ForwardSOCKS()
{
LogPrint(eLogInfo, "SOCKS: forwarding to upstream");
EnterState(UPSTREAM_RESOLVE);
auto & service = GetOwner()->GetService();
boost::asio::ip::tcp::resolver::query q(m_UpstreamProxyAddress,boost::lexical_cast<std::string>(m_UpstreamProxyPort) );
m_proxy_resolver.async_resolve(q, std::bind(&SOCKSHandler::HandleUpstreamResolved, shared_from_this(),
std::placeholders::_1, std::placeholders::_2));
}
void SOCKSHandler::AsyncUpstreamSockRead()
{
LogPrint(eLogDebug, "SOCKS: async upstream sock read");
if (m_upstreamSock) {
m_upstreamSock->async_read_some(boost::asio::buffer(m_upstream_response, SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE),
std::bind(&SOCKSHandler::HandleUpstreamSockRecv, shared_from_this(),
std::placeholders::_1, std::placeholders::_2));
} else {
LogPrint(eLogError, "SOCKS: no upstream socket for read");
SocksRequestFailed(SOCKS5_GEN_FAIL);
}
}
void SOCKSHandler::HandleUpstreamSockRecv(const boost::system::error_code & ecode, std::size_t bytes_transfered)
{
if (ecode) {
if (m_state == UPSTREAM_HANDSHAKE ) {
// we are trying to handshake but it failed
SocksRequestFailed(SOCKS5_NET_UNREACH);
} else {
LogPrint(eLogError, "SOCKS: bad state when reading from upstream: ", (int) m_state);
}
return;
}
HandleUpstreamData(m_upstream_response, bytes_transfered);
}
void SOCKSHandler::SocksUpstreamSuccess()
{
LogPrint(eLogInfo, "SOCKS: upstream success");
boost::asio::const_buffers_1 response(nullptr, 0);
switch (m_socksv)
{
case SOCKS4:
LogPrint(eLogInfo, "SOCKS: v4 connection success");
response = GenerateSOCKS4Response(SOCKS4_OK, m_4aip, m_port);
break;
case SOCKS5:
LogPrint(eLogInfo, "SOCKS: v5 connection success");
//HACK only 16 bits passed in port as SOCKS5 doesn't allow for more
response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, m_address, m_port);
break;
}
m_sock->send(response);
auto forwarder = std::make_shared<i2p::client::TCPIPPipe>(GetOwner(), m_sock, m_upstreamSock);
m_upstreamSock = nullptr;
m_sock = nullptr;
GetOwner()->AddHandler(forwarder);
forwarder->Start();
Terminate();
}
void SOCKSHandler::HandleUpstreamData(uint8_t * dataptr, std::size_t len)
{
if (m_state == UPSTREAM_HANDSHAKE) {
m_upstream_response_len += len;
// handle handshake data
if (m_upstream_response_len < SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) {
// too small, continue reading
AsyncUpstreamSockRead();
} else if (len == SOCKS_UPSTREAM_SOCKS4A_REPLY_SIZE) {
// just right
uint8_t resp = m_upstream_response[1];
if (resp == SOCKS4_OK) {
// we have connected !
SocksUpstreamSuccess();
} else {
// upstream failure
LogPrint(eLogError, "SOCKS: upstream proxy failure: ", (int) resp);
// TODO: runtime error?
SocksRequestFailed(SOCKS5_GEN_FAIL);
}
} else {
// too big
SocksRequestFailed(SOCKS5_GEN_FAIL);
}
} else {
// invalid state
LogPrint(eLogError, "SOCKS: invalid state reading from upstream: ", (int) m_state);
}
}
void SOCKSHandler::SendUpstreamRequest()
{
LogPrint(eLogInfo, "SOCKS: negotiating with upstream proxy");
EnterState(UPSTREAM_HANDSHAKE);
if (m_upstreamSock) {
boost::asio::write(*m_upstreamSock,
GenerateUpstreamRequest());
AsyncUpstreamSockRead();
} else {
LogPrint(eLogError, "SOCKS: no upstream socket to send handshake to");
}
}
void SOCKSHandler::HandleUpstreamConnected(const boost::system::error_code & ecode, boost::asio::ip::tcp::resolver::iterator itr)
{
if (ecode) {
LogPrint(eLogWarning, "SOCKS: could not connect to upstream proxy: ", ecode.message());
SocksRequestFailed(SOCKS5_NET_UNREACH);
return;
}
LogPrint(eLogInfo, "SOCKS: connected to upstream proxy");
SendUpstreamRequest();
}
void SOCKSHandler::HandleUpstreamResolved(const boost::system::error_code & ecode, boost::asio::ip::tcp::resolver::iterator itr)
{
if (ecode) {
// error resolving
LogPrint(eLogWarning, "SOCKS: upstream proxy", m_UpstreamProxyAddress, " not resolved: ", ecode.message());
SocksRequestFailed(SOCKS5_NET_UNREACH);
return;
}
LogPrint(eLogInfo, "SOCKS: upstream proxy resolved");
EnterState(UPSTREAM_CONNECT);
auto & service = GetOwner()->GetService();
m_upstreamSock = std::make_shared<boost::asio::ip::tcp::socket>(service);
boost::asio::async_connect(*m_upstreamSock, itr,
std::bind(&SOCKSHandler::HandleUpstreamConnected,
shared_from_this(), std::placeholders::_1, std::placeholders::_2));
}
SOCKSServer::SOCKSServer(const std::string& address, int port, const std::string& outAddress, uint16_t outPort,
std::shared_ptr<i2p::client::ClientDestination> localDestination) :
TCPIPAcceptor (address, port, localDestination ? localDestination : i2p::client::context.GetSharedLocalDestination ())
{
m_UseUpstreamProxy = false;
if (outAddress.length() > 0)
SetUpstreamProxy(outAddress, outPort);
}
std::shared_ptr<i2p::client::I2PServiceHandler> SOCKSServer::CreateHandler(std::shared_ptr<boost::asio::ip::tcp::socket> socket)
{
return std::make_shared<SOCKSHandler> (this, socket, m_UpstreamProxyAddress, m_UpstreamProxyPort, m_UseUpstreamProxy);
}
void SOCKSServer::SetUpstreamProxy(const std::string & addr, const uint16_t port)
{
m_UpstreamProxyAddress = addr;
m_UpstreamProxyPort = port;
m_UseUpstreamProxy = true;
}
}
}
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