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I2P: End-to-End encrypted and anonymous Internet
https://i2pd.website/
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507 lines
14 KiB
507 lines
14 KiB
#include "SOCKS.h" |
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#include "Identity.h" |
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#include "NetDb.h" |
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#include "Destination.h" |
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#include "ClientContext.h" |
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#include "I2PEndian.h" |
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#include <cstring> |
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#include <cassert> |
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namespace i2p |
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{ |
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namespace proxy |
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{ |
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void SOCKSHandler::AsyncSockRead() |
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{ |
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LogPrint(eLogDebug,"--- SOCKS async sock read"); |
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if(m_sock) { |
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m_sock->async_receive(boost::asio::buffer(m_sock_buff, socks_buffer_size), |
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std::bind(&SOCKSHandler::HandleSockRecv, this, |
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std::placeholders::_1, std::placeholders::_2)); |
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} else { |
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LogPrint(eLogError,"--- SOCKS no socket for read"); |
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} |
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} |
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void SOCKSHandler::Terminate() { |
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CloseStream(); |
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CloseSock(); |
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delete this; // HACK: ew |
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} |
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boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS5SelectAuth(SOCKSHandler::authMethods method) |
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{ |
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response[0] = '\x05'; //Version |
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response[1] = method; //Response code |
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return boost::asio::const_buffers_1(response,2); |
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} |
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boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS4Response(SOCKSHandler::errTypes error, uint32_t ip, uint16_t port) |
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{ |
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assert(error >= SOCKS4_OK); |
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assert(type == ADDR_IPV4); |
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response[0] = '\x00'; //Version |
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response[1] = error; //Response code |
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htobe16buf(response+2,port); //Port |
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htobe32buf(response+4,ip); //IP |
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return boost::asio::const_buffers_1(response,8); |
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} |
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boost::asio::const_buffers_1 SOCKSHandler::GenerateSOCKS5Response(SOCKSHandler::errTypes error, SOCKSHandler::addrTypes type, |
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const SOCKSHandler::address &addr, uint16_t port) |
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{ |
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size_t size; |
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assert(error <= SOCKS5_ADDR_UNSUP); |
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response[0] = '\x05'; //Version |
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response[1] = error; //Response code |
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response[2] = '\x00'; //RSV |
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response[3] = type; //Address type |
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switch (type) { |
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case ADDR_IPV4: |
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size = 10; |
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htobe32buf(response+4,addr.ip); |
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break; |
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case ADDR_IPV6: |
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size = 22; |
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memcpy(response+4,addr.ipv6, 16); |
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break; |
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case ADDR_DNS: |
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size = 7+addr.dns.size; |
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response[4] = addr.dns.size; |
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memcpy(response+5,addr.dns.value, addr.dns.size); |
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break; |
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} |
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htobe16buf(response+size-2,port); //Port |
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return boost::asio::const_buffers_1(response,size); |
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} |
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/* Ah ah ah, you didn't say the magic word */ |
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void SOCKSHandler::Socks5AuthNegoFailed() |
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{ |
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LogPrint(eLogWarning,"--- SOCKS5 authentication negotiation failed"); |
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boost::asio::async_write(*m_sock, GenerateSOCKS5SelectAuth(AUTH_UNACCEPTABLE), |
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std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); |
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} |
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void SOCKSHandler::Socks5ChooseAuth() |
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{ |
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LogPrint(eLogDebug,"--- SOCKS5 choosing authentication method: ", m_authchosen); |
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boost::asio::async_write(*m_sock, GenerateSOCKS5SelectAuth(m_authchosen), |
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std::bind(&SOCKSHandler::SentSocksResponse, this, std::placeholders::_1)); |
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} |
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/* All hope is lost beyond this point */ |
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void SOCKSHandler::SocksRequestFailed(SOCKSHandler::errTypes error) |
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{ |
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boost::asio::const_buffers_1 response(nullptr,0); |
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assert(error != SOCKS4_OK && error != SOCKS5_OK); |
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switch (m_socksv) { |
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case SOCKS4: |
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LogPrint(eLogWarning,"--- SOCKS4 failed: ", error); |
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if (error < SOCKS4_OK) error = SOCKS4_FAIL; //Transparently map SOCKS5 errors |
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response = GenerateSOCKS4Response(error, m_4aip, m_port); |
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break; |
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case SOCKS5: |
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LogPrint(eLogWarning,"--- SOCKS5 failed: ", error); |
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response = GenerateSOCKS5Response(error, m_addrtype, m_address, m_port); |
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break; |
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} |
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boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed, this, std::placeholders::_1)); |
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} |
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void SOCKSHandler::SocksRequestSuccess() |
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{ |
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boost::asio::const_buffers_1 response(nullptr,0); |
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//TODO: this should depend on things like the command type and callbacks may change |
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switch (m_socksv) { |
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case SOCKS4: |
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LogPrint(eLogInfo,"--- SOCKS4 connection success"); |
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response = GenerateSOCKS4Response(SOCKS4_OK, m_4aip, m_port); |
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break; |
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case SOCKS5: |
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LogPrint(eLogInfo,"--- SOCKS5 connection success"); |
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auto s = i2p::client::context.GetAddressBook().ToAddress(m_parent->GetLocalDestination()->GetIdentHash()); |
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address ad; ad.dns.FromString(s); |
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//HACK only 16 bits passed in port as SOCKS5 doesn't allow for more |
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response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, ad, m_stream->GetSendStreamID()); |
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break; |
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} |
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boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksResponse, this, std::placeholders::_1)); |
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} |
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void SOCKSHandler::CloseSock() |
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{ |
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if (m_sock) { |
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LogPrint(eLogDebug,"--- SOCKS close sock"); |
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m_sock->close(); |
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delete m_sock; |
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m_sock = nullptr; |
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} |
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} |
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void SOCKSHandler::CloseStream() |
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{ |
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if (m_stream) { |
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LogPrint(eLogDebug,"--- SOCKS close stream"); |
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m_stream.reset (); |
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} |
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} |
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std::size_t SOCKSHandler::HandleData(uint8_t *sock_buff, std::size_t len) |
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{ |
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assert(len); // This should always be called with a least a byte left to parse |
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switch (m_state) { |
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case GET_VERSION: |
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return HandleVersion(sock_buff); |
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case SOCKS5_AUTHNEGO: |
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return HandleSOCKS5AuthNego(sock_buff,len); |
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case SOCKS_REQUEST: |
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return HandleSOCKSRequest(sock_buff,len); |
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default: |
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LogPrint(eLogError,"--- SOCKS state?? ", m_state); |
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Terminate(); |
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return 0; |
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} |
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} |
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std::size_t SOCKSHandler::HandleVersion(uint8_t *sock_buff) |
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{ |
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switch (*sock_buff) { |
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case SOCKS4: |
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m_state = SOCKS_REQUEST; // Switch to the 4 handler |
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m_pstate = GET_COMMAND; //Initialize the parser at the right position |
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break; |
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case SOCKS5: |
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m_state = SOCKS5_AUTHNEGO; // Switch to the 5 handler |
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m_pstate = GET5_AUTHNUM; //Initialize the parser at the right position |
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break; |
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default: |
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LogPrint(eLogError,"--- SOCKS rejected invalid version: ", ((int)*sock_buff)); |
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Terminate(); |
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return 0; |
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} |
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m_socksv = (SOCKSHandler::socksVersions) *sock_buff; |
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return 1; |
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} |
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std::size_t SOCKSHandler::HandleSOCKS5AuthNego(uint8_t *sock_buff, std::size_t len) |
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{ |
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std::size_t rv = 0; |
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while (len > 0) { |
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rv++; |
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switch (m_pstate) |
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{ |
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case GET5_AUTHNUM: |
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m_parseleft = *sock_buff; |
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m_pstate = GET5_AUTH; |
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break; |
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case GET5_AUTH: |
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m_parseleft --; |
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if (*sock_buff == AUTH_NONE) |
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m_authchosen = AUTH_NONE; |
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if ( m_parseleft == 0 ) { |
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if (m_authchosen == AUTH_UNACCEPTABLE) { |
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//TODO: we maybe want support for other methods! |
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LogPrint(eLogError,"--- SOCKS5 couldn't negotiate authentication"); |
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Socks5AuthNegoFailed(); |
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return 0; |
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} |
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m_pstate = GET5_REQUESTV; |
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m_state = SOCKS_REQUEST; |
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m_need_more = false; |
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Socks5ChooseAuth(); |
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return rv; |
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} |
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break; |
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default: |
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LogPrint(eLogError,"--- SOCKS5 parse state?? ", m_pstate); |
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Terminate(); |
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return 0; |
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} |
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sock_buff++; |
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len--; |
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} |
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return rv; |
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} |
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bool SOCKSHandler::ValidateSOCKSRequest() { |
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if ( m_cmd != CMD_CONNECT ) { |
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//TODO: we need to support binds and other shit! |
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LogPrint(eLogError,"--- SOCKS unsupported command: ", m_cmd); |
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SocksRequestFailed(SOCKS5_CMD_UNSUP); |
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return false; |
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} |
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//TODO: we may want to support other address types! |
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if ( m_addrtype != ADDR_DNS ) { |
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switch (m_socksv) { |
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case SOCKS5: |
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LogPrint(eLogError,"--- SOCKS5 unsupported address type: ", m_addrtype); |
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break; |
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case SOCKS4: |
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LogPrint(eLogError,"--- SOCKS4a rejected because it's actually SOCKS4"); |
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break; |
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} |
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SocksRequestFailed(SOCKS5_ADDR_UNSUP); |
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return false; |
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} |
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//TODO: we may want to support other domains |
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if(m_addrtype == ADDR_DNS && m_address.dns.ToString().find(".i2p") == std::string::npos) { |
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LogPrint(eLogError,"--- SOCKS invalid hostname: ", m_address.dns.ToString()); |
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SocksRequestFailed(SOCKS5_ADDR_UNSUP); |
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return false; |
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} |
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return true; |
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} |
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std::size_t SOCKSHandler::HandleSOCKSRequest(uint8_t *sock_buff, std::size_t len) |
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{ |
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std::size_t rv = 0; |
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while (len > 0) { |
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rv++; |
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switch (m_pstate) |
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{ |
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case GET_COMMAND: |
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switch (*sock_buff) { |
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case CMD_CONNECT: |
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case CMD_BIND: |
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break; |
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case CMD_UDP: |
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if (m_socksv == SOCKS5) break; |
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default: |
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LogPrint(eLogError,"--- SOCKS invalid command: ", ((int)*sock_buff)); |
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SocksRequestFailed(SOCKS5_GEN_FAIL); |
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return 0; |
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} |
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m_cmd = (SOCKSHandler::cmdTypes)*sock_buff; |
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switch (m_socksv) { |
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case SOCKS5: m_pstate = GET5_GETRSV; break; |
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case SOCKS4: m_pstate = GET_PORT; m_parseleft = 2; break; |
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} |
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break; |
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case GET_PORT: |
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m_port = (m_port << 8)|((uint16_t)*sock_buff); |
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m_parseleft--; |
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if (m_parseleft == 0) { |
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switch (m_socksv) { |
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case SOCKS5: m_pstate = DONE; break; |
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case SOCKS4: m_pstate = GET_IPV4; m_address.ip = 0; m_parseleft = 4; break; |
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} |
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} |
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break; |
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case GET_IPV4: |
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m_address.ip = (m_address.ip << 8)|((uint32_t)*sock_buff); |
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m_parseleft--; |
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if (m_parseleft == 0) { |
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switch (m_socksv) { |
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case SOCKS5: m_pstate = GET_PORT; m_parseleft = 2; break; |
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case SOCKS4: m_pstate = GET4_IDENT; m_4aip = m_address.ip; break; |
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} |
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} |
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break; |
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case GET4_IDENT: |
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if (!*sock_buff) { |
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if( m_4aip == 0 || m_4aip > 255 ) { |
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m_addrtype = ADDR_IPV4; |
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m_pstate = DONE; |
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} else { |
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m_addrtype = ADDR_DNS; |
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m_pstate = GET4A_HOST; |
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m_address.dns.size = 0; |
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} |
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} |
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break; |
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case GET4A_HOST: |
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if (!*sock_buff) { |
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m_pstate = DONE; |
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break; |
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} |
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if (m_address.dns.size >= max_socks_hostname_size) { |
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LogPrint(eLogError,"--- SOCKS4a destination is too large"); |
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SocksRequestFailed(SOCKS4_FAIL); |
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return 0; |
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} |
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m_address.dns.push_back(*sock_buff); |
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break; |
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case GET5_REQUESTV: |
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if (*sock_buff != SOCKS5) { |
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LogPrint(eLogError,"--- SOCKS5 rejected unknown request version: ", ((int)*sock_buff)); |
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SocksRequestFailed(SOCKS5_GEN_FAIL); |
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return 0; |
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} |
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m_pstate = GET_COMMAND; |
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break; |
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case GET5_GETRSV: |
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if ( *sock_buff != 0 ) { |
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LogPrint(eLogError,"--- SOCKS5 unknown reserved field: ", ((int)*sock_buff)); |
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SocksRequestFailed(SOCKS5_GEN_FAIL); |
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return 0; |
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} |
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m_pstate = GET5_GETADDRTYPE; |
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break; |
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case GET5_GETADDRTYPE: |
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switch (*sock_buff) { |
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case ADDR_IPV4: m_pstate = GET_IPV4; m_address.ip = 0; m_parseleft = 4; break; |
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case ADDR_IPV6: m_pstate = GET5_IPV6; m_parseleft = 16; break; |
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case ADDR_DNS : m_pstate = GET5_HOST_SIZE; break; |
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default: |
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LogPrint(eLogError,"--- SOCKS5 unknown address type: ", ((int)*sock_buff)); |
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SocksRequestFailed(SOCKS5_GEN_FAIL); |
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return 0; |
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} |
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m_addrtype = (SOCKSHandler::addrTypes)*sock_buff; |
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break; |
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case GET5_IPV6: |
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m_address.ipv6[16-m_parseleft] = *sock_buff; |
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m_parseleft--; |
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if (m_parseleft == 0) { |
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m_pstate = GET_PORT; |
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m_parseleft = 2; |
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} |
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break; |
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case GET5_HOST_SIZE: |
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m_parseleft = *sock_buff; |
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m_address.dns.size = 0; |
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m_pstate = GET5_HOST; |
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break; |
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case GET5_HOST: |
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m_address.dns.push_back(*sock_buff); |
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m_parseleft--; |
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if (m_parseleft == 0) { |
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m_pstate = GET_PORT; |
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m_parseleft = 2; |
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} |
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break; |
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default: |
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LogPrint(eLogError,"--- SOCKS parse state?? ", m_pstate); |
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Terminate(); |
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return 0; |
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} |
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if (m_pstate == DONE) { |
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m_state = READY; |
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m_need_more = false; |
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return (ValidateSOCKSRequest() ? rv : 0); |
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} |
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sock_buff++; |
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len--; |
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} |
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return rv; |
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} |
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void SOCKSHandler::HandleSockRecv(const boost::system::error_code & ecode, std::size_t len) |
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{ |
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LogPrint(eLogDebug,"--- SOCKS sock recv: ", len); |
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if(ecode) { |
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LogPrint(eLogWarning," --- SOCKS sock recv got error: ", ecode); |
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Terminate(); |
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return; |
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} |
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std::size_t pos = 0; |
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m_need_more = true; |
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while (pos != len && m_state != READY && m_need_more) { |
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assert(pos < len); //We are overflowing the buffer otherwise |
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std::size_t rv = HandleData(m_sock_buff + pos, len - pos); |
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if (!rv) return; //Something went wrong die misserably |
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pos += rv; |
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} |
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assert(!(m_state == READY && m_need_more)); |
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if (m_state == READY) { |
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LogPrint(eLogInfo,"--- SOCKS requested ", m_address.dns.ToString(), ":" , m_port); |
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if (pos != len) { |
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LogPrint(eLogError,"--- SOCKS rejected because we can't handle extra data"); |
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SocksRequestFailed(SOCKS5_GEN_FAIL); |
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return ; |
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} |
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m_parent->GetLocalDestination ()->CreateStream ( |
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std::bind (&SOCKSHandler::HandleStreamRequestComplete, |
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this, std::placeholders::_1), m_address.dns.ToString(), m_port); |
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} else if (m_need_more) { |
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LogPrint (eLogDebug,"--- SOCKS Need more data"); |
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AsyncSockRead(); |
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} |
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} |
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void SOCKSHandler::SentSocksFailed(const boost::system::error_code & ecode) |
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{ |
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if (!ecode) { |
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Terminate(); |
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} else { |
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LogPrint (eLogError,"--- SOCKS Closing socket after sending failure because: ", ecode.message ()); |
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Terminate(); |
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} |
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} |
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void SOCKSHandler::SentSocksResponse(const boost::system::error_code & ecode) |
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{ |
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if (!ecode) { |
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if(m_state == READY) { |
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LogPrint (eLogInfo,"--- SOCKS New I2PTunnel connection"); |
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auto connection = std::make_shared<i2p::client::I2PTunnelConnection>((i2p::client::I2PTunnel *)m_parent, m_sock, m_stream); |
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m_parent->AddConnection (connection); |
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connection->I2PConnect (); |
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} else { |
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LogPrint (eLogDebug,"--- SOCKS Go to next state"); |
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AsyncSockRead(); |
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} |
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} |
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else |
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{ |
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LogPrint (eLogError,"--- SOCKS Closing socket after sending reply because: ", ecode.message ()); |
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Terminate(); |
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} |
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} |
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void SOCKSHandler::HandleStreamRequestComplete (std::shared_ptr<i2p::stream::Stream> stream) |
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{ |
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if (stream) { |
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//TODO: test the stream is open if it isn't fail with connrefused |
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m_stream = stream; |
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SocksRequestSuccess(); |
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} else { |
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LogPrint (eLogError,"--- SOCKS Issue when creating the stream, check the previous warnings for more info."); |
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SocksRequestFailed(SOCKS5_HOST_UNREACH); |
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} |
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} |
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void SOCKSServer::Start () |
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{ |
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m_Acceptor.listen (); |
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Accept (); |
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} |
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void SOCKSServer::Stop () |
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{ |
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m_Acceptor.close(); |
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m_Timer.cancel (); |
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ClearConnections (); |
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} |
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void SOCKSServer::Accept () |
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{ |
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auto newSocket = new boost::asio::ip::tcp::socket (GetService ()); |
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m_Acceptor.async_accept (*newSocket, std::bind (&SOCKSServer::HandleAccept, this, |
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std::placeholders::_1, newSocket)); |
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} |
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void SOCKSServer::HandleAccept (const boost::system::error_code& ecode, boost::asio::ip::tcp::socket * socket) |
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{ |
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if (!ecode) |
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{ |
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LogPrint(eLogDebug,"--- SOCKS accepted"); |
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new SOCKSHandler(this, socket); |
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Accept(); |
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} |
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else |
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{ |
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LogPrint (eLogError,"--- SOCKS Closing socket on accept because: ", ecode.message ()); |
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delete socket; |
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} |
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} |
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} |
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}
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