From 31b0fbd5233677e81082aa7d9936c34c99c6e26a Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Sat, 23 Sep 2017 10:36:23 +0200 Subject: [PATCH] net: Improve and document SOCKS code >>> backports bitcoin/bitcoin@22f816ef4dd57785627d801c247714cace7fc5b5 Make the SOCKS code more consistent, and document the constants used. --- src/netbase.cpp | 153 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 101 insertions(+), 52 deletions(-) diff --git a/src/netbase.cpp b/src/netbase.cpp index 934dc38846c48..9dbe377f5ebf8 100644 --- a/src/netbase.cpp +++ b/src/netbase.cpp @@ -198,6 +198,48 @@ struct timeval MillisToTimeval(int64_t nTimeout) return timeout; } +/** SOCKS version */ +enum SOCKSVersion: uint8_t { + SOCKS4 = 0x04, + SOCKS5 = 0x05 +}; + +/** Values defined for METHOD in RFC1928 */ +enum SOCKS5Method: uint8_t { + NOAUTH = 0x00, //! No authentication required + GSSAPI = 0x01, //! GSSAPI + USER_PASS = 0x02, //! Username/password + NO_ACCEPTABLE = 0xff, //! No acceptable methods +}; + +/** Values defined for CMD in RFC1928 */ +enum SOCKS5Command: uint8_t { + CONNECT = 0x01, + BIND = 0x02, + UDP_ASSOCIATE = 0x03 +}; + +/** Values defined for REP in RFC1928 */ +enum SOCKS5Reply: uint8_t { + SUCCEEDED = 0x00, //! Succeeded + GENFAILURE = 0x01, //! General failure + NOTALLOWED = 0x02, //! Connection not allowed by ruleset + NETUNREACHABLE = 0x03, //! Network unreachable + HOSTUNREACHABLE = 0x04, //! Network unreachable + CONNREFUSED = 0x05, //! Connection refused + TTLEXPIRED = 0x06, //! TTL expired + CMDUNSUPPORTED = 0x07, //! Command not supported + ATYPEUNSUPPORTED = 0x08, //! Address type not supported +}; + +/** Values defined for ATYPE in RFC1928 */ +enum SOCKS5Atyp: uint8_t { + IPV4 = 0x01, + DOMAINNAME = 0x03, + IPV6 = 0x04, +}; + +/** Status codes that can be returned by InterruptibleRecv */ enum class IntrRecvError { OK, Timeout, @@ -217,7 +259,7 @@ enum class IntrRecvError { * * @note This function requires that hSocket is in non-blocking mode. */ -static IntrRecvError InterruptibleRecv(char* data, size_t len, int timeout, SOCKET& hSocket) +static IntrRecvError InterruptibleRecv(uint8_t* data, size_t len, int timeout, const SOCKET& hSocket) { int64_t curTime = GetTimeMillis(); int64_t endTime = curTime + timeout; @@ -225,7 +267,7 @@ static IntrRecvError InterruptibleRecv(char* data, size_t len, int timeout, SOCK // to break off in case of an interruption. const int64_t maxWait = 1000; while (len > 0 && curTime < endTime) { - ssize_t ret = recv(hSocket, data, len, 0); // Optimistically try the recv first + ssize_t ret = recv(hSocket, (char*)data, len, 0); // Optimistically try the recv first if (ret > 0) { len -= ret; data += ret; @@ -256,24 +298,35 @@ static IntrRecvError InterruptibleRecv(char* data, size_t len, int timeout, SOCK return len == 0 ? IntrRecvError::OK : IntrRecvError::Timeout; } +/** Credentials for proxy authentication */ struct ProxyCredentials { std::string username; std::string password; }; -std::string static Socks5ErrorString(int err) +/** Convert SOCKS5 reply to a an error message */ +static std::string Socks5ErrorString(uint8_t err) { switch(err) { - case 0x01: return "general failure"; - case 0x02: return "connection not allowed"; - case 0x03: return "network unreachable"; - case 0x04: return "host unreachable"; - case 0x05: return "connection refused"; - case 0x06: return "TTL expired"; - case 0x07: return "protocol error"; - case 0x08: return "address type not supported"; - default: return "unknown"; + case SOCKS5Reply::GENFAILURE: + return "general failure"; + case SOCKS5Reply::NOTALLOWED: + return "connection not allowed"; + case SOCKS5Reply::NETUNREACHABLE: + return "network unreachable"; + case SOCKS5Reply::HOSTUNREACHABLE: + return "host unreachable"; + case SOCKS5Reply::CONNREFUSED: + return "connection refused"; + case SOCKS5Reply::TTLEXPIRED: + return "TTL expired"; + case SOCKS5Reply::CMDUNSUPPORTED: + return "protocol error"; + case SOCKS5Reply::ATYPEUNSUPPORTED: + return "address type not supported"; + default: + return "unknown"; } } @@ -288,34 +341,34 @@ bool static Socks5(std::string strDest, int port, const ProxyCredentials *auth, } // Accepted authentication methods std::vector vSocks5Init; - vSocks5Init.push_back(0x05); + vSocks5Init.push_back(SOCKSVersion::SOCKS5); if (auth) { - vSocks5Init.push_back(0x02); // # METHODS - vSocks5Init.push_back(0x00); // X'00' NO AUTHENTICATION REQUIRED - vSocks5Init.push_back(0x02); // X'02' USERNAME/PASSWORD (RFC1929) + vSocks5Init.push_back(0x02); // Number of methods + vSocks5Init.push_back(SOCKS5Method::NOAUTH); + vSocks5Init.push_back(SOCKS5Method::USER_PASS); } else { - vSocks5Init.push_back(0x01); // # METHODS - vSocks5Init.push_back(0x00); // X'00' NO AUTHENTICATION REQUIRED + vSocks5Init.push_back(0x01); // Number of methods + vSocks5Init.push_back(SOCKS5Method::NOAUTH); } ssize_t ret = send(hSocket, (const char*)vSocks5Init.data(), vSocks5Init.size(), MSG_NOSIGNAL); if (ret != (ssize_t)vSocks5Init.size()) { CloseSocket(hSocket); return error("Error sending to proxy"); } - char pchRet1[2]; + uint8_t pchRet1[2]; if ((recvr = InterruptibleRecv(pchRet1, 2, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) { CloseSocket(hSocket); LogPrintf("Socks5() connect to %s:%d failed: InterruptibleRecv() timeout or other failure\n", strDest, port); return false; } - if (pchRet1[0] != 0x05) { + if (pchRet1[0] != SOCKSVersion::SOCKS5) { CloseSocket(hSocket); return error("Proxy failed to initialize"); } - if (pchRet1[1] == 0x02 && auth) { + if (pchRet1[1] == SOCKS5Method::USER_PASS && auth) { // Perform username/password authentication (as described in RFC1929) std::vector vAuth; - vAuth.push_back(0x01); + vAuth.push_back(0x01); // Current (and only) version of user/pass subnegotiation if (auth->username.size() > 255 || auth->password.size() > 255) return error("Proxy username or password too long"); vAuth.push_back(auth->username.size()); @@ -328,7 +381,7 @@ bool static Socks5(std::string strDest, int port, const ProxyCredentials *auth, return error("Error sending authentication to proxy"); } LogPrint(BCLog::PROXY, "SOCKS5 sending proxy authentication %s:%s\n", auth->username, auth->password); - char pchRetA[2]; + uint8_t pchRetA[2]; if ((recvr = InterruptibleRecv(pchRetA, 2, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) { CloseSocket(hSocket); return error("Error reading proxy authentication response"); @@ -337,17 +390,17 @@ bool static Socks5(std::string strDest, int port, const ProxyCredentials *auth, CloseSocket(hSocket); return error("Proxy authentication unsuccesful"); } - } else if (pchRet1[1] == 0x00) { + } else if (pchRet1[1] == SOCKS5Method::NOAUTH) { // Perform no authentication } else { CloseSocket(hSocket); return error("Proxy requested wrong authentication method %02x", pchRet1[1]); } std::vector vSocks5; - vSocks5.push_back(0x05); // VER protocol version - vSocks5.push_back(0x01); // CMD CONNECT - vSocks5.push_back(0x00); // RSV Reserved - vSocks5.push_back(0x03); // ATYP DOMAINNAME + vSocks5.push_back(SOCKSVersion::SOCKS5); // VER protocol version + vSocks5.push_back(SOCKS5Command::CONNECT); // CMD CONNECT + vSocks5.push_back(0x00); // RSV Reserved must be 0 + vSocks5.push_back(SOCKS5Atyp::DOMAINNAME); // ATYP DOMAINNAME vSocks5.push_back(strDest.size()); // Length<=255 is checked at beginning of function vSocks5.insert(vSocks5.end(), strDest.begin(), strDest.end()); vSocks5.push_back((port >> 8) & 0xFF); @@ -357,7 +410,7 @@ bool static Socks5(std::string strDest, int port, const ProxyCredentials *auth, CloseSocket(hSocket); return error("Error sending to proxy"); } - char pchRet2[4]; + uint8_t pchRet2[4]; if ((recvr = InterruptibleRecv(pchRet2, 4, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) { CloseSocket(hSocket); if (recvr == IntrRecvError::Timeout) { @@ -369,41 +422,37 @@ bool static Socks5(std::string strDest, int port, const ProxyCredentials *auth, return error("Error while reading proxy response"); } } - if (pchRet2[0] != 0x05) { + if (pchRet2[0] != SOCKSVersion::SOCKS5) { CloseSocket(hSocket); return error("Proxy failed to accept request"); } - if (pchRet2[1] != 0x00) { + if (pchRet2[1] != SOCKS5Reply::SUCCEEDED) { // Failures to connect to a peer that are not proxy errors CloseSocket(hSocket); LogPrintf("Socks5() connect to %s:%d failed: %s\n", strDest, port, Socks5ErrorString(pchRet2[1])); return false; } - if (pchRet2[2] != 0x00) { + if (pchRet2[2] != 0x00) { // Reserved field must be 0 CloseSocket(hSocket); return error("Error: malformed proxy response"); } - char pchRet3[256]; - switch (pchRet2[3]) { - case 0x01: - recvr = InterruptibleRecv(pchRet3, 4, SOCKS5_RECV_TIMEOUT, hSocket); - break; - case 0x04: - recvr = InterruptibleRecv(pchRet3, 16, SOCKS5_RECV_TIMEOUT, hSocket); - break; - case 0x03: { - recvr = InterruptibleRecv(pchRet3, 1, SOCKS5_RECV_TIMEOUT, hSocket); - if (recvr != IntrRecvError::OK) { - CloseSocket(hSocket); - return error("Error reading from proxy"); + uint8_t pchRet3[256]; + switch (pchRet2[3]) + { + case SOCKS5Atyp::IPV4: recvr = InterruptibleRecv(pchRet3, 4, SOCKS5_RECV_TIMEOUT, hSocket); break; + case SOCKS5Atyp::IPV6: recvr = InterruptibleRecv(pchRet3, 16, SOCKS5_RECV_TIMEOUT, hSocket); break; + case SOCKS5Atyp::DOMAINNAME: + { + recvr = InterruptibleRecv(pchRet3, 1, SOCKS5_RECV_TIMEOUT, hSocket); + if (recvr != IntrRecvError::OK) { + CloseSocket(hSocket); + return error("Error reading from proxy"); + } + int nRecv = pchRet3[0]; + recvr = InterruptibleRecv(pchRet3, nRecv, SOCKS5_RECV_TIMEOUT, hSocket); + break; } - int nRecv = pchRet3[0]; - recvr = InterruptibleRecv(pchRet3, nRecv, SOCKS5_RECV_TIMEOUT, hSocket); - break; - } - default: - CloseSocket(hSocket); - return error("Error: malformed proxy response"); + default: CloseSocket(hSocket); return error("Error: malformed proxy response"); } if (recvr != IntrRecvError::OK) { CloseSocket(hSocket);