From 6050ab685553c7312ef105d2c4a5230c3fcf4002 Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Mon, 8 Sep 2014 13:49:56 +0200 Subject: [PATCH] netbase: Make SOCKS5 negotiation interruptible Avoids that SOCKS5 negotiation will hold up the shutdown process. - Sockets can stay in non-blocking mode, no need to switch it on/off anymore - Adds a timeout (20 seconds) on SOCK5 negotiation. This should be enough for even Tor to get a connection to a hidden service, and avoids blocking the opencon thread indefinitely on a hanging proxy. Fixes #2954. --- src/net.cpp | 4 --- src/netbase.cpp | 88 +++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 70 insertions(+), 22 deletions(-) diff --git a/src/net.cpp b/src/net.cpp index 633a3a34..4c9ff4eb 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -488,10 +488,6 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest) { addrman.Attempt(addrConnect); - // Set to non-blocking - if (!SetSocketNonBlocking(hSocket, true)) - LogPrintf("ConnectNode: Setting socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError())); - // Add node CNode* pnode = new CNode(hSocket, addrConnect, pszDest ? pszDest : "", false); pnode->AddRef(); diff --git a/src/netbase.cpp b/src/netbase.cpp index 954c11f7..5819c152 100644 --- a/src/netbase.cpp +++ b/src/netbase.cpp @@ -45,6 +45,9 @@ bool fNameLookup = false; static const unsigned char pchIPv4[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff }; +// Need ample time for negotiation for very slow proxies such as Tor (milliseconds) +static const int SOCKS5_RECV_TIMEOUT = 20 * 1000; + enum Network ParseNetwork(std::string net) { boost::to_lower(net); if (net == "ipv4") return NET_IPV4; @@ -225,6 +228,63 @@ bool LookupNumeric(const char *pszName, CService& addr, int portDefault) return Lookup(pszName, addr, portDefault, false); } +/** + * Convert milliseconds to a struct timeval for select. + */ +struct timeval static MillisToTimeval(int64_t nTimeout) +{ + struct timeval timeout; + timeout.tv_sec = nTimeout / 1000; + timeout.tv_usec = (nTimeout % 1000) * 1000; + return timeout; +} + +/** + * Read bytes from socket. This will either read the full number of bytes requested + * or return False on error or timeout. + * This function can be interrupted by boost thread interrupt. + * + * @param data Buffer to receive into + * @param len Length of data to receive + * @param timeout Timeout in milliseconds for receive operation + * + * @note This function requires that hSocket is in non-blocking mode. + */ +bool static InterruptibleRecv(char* data, size_t len, int timeout, SOCKET& hSocket) +{ + int64_t curTime = GetTimeMillis(); + int64_t endTime = curTime + timeout; + // Maximum time to wait in one select call. It will take up until this time (in millis) + // 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 + if (ret > 0) { + len -= ret; + data += ret; + } else if (ret == 0) { // Unexpected disconnection + return false; + } else { // Other error or blocking + int nErr = WSAGetLastError(); + if (nErr == WSAEINPROGRESS || nErr == WSAEWOULDBLOCK || nErr == WSAEINVAL) { + struct timeval tval = MillisToTimeval(std::min(endTime - curTime, maxWait)); + fd_set fdset; + FD_ZERO(&fdset); + FD_SET(hSocket, &fdset); + int nRet = select(hSocket + 1, &fdset, NULL, NULL, &tval); + if (nRet == SOCKET_ERROR) { + return false; + } + } else { + return false; + } + } + boost::this_thread::interruption_point(); + curTime = GetTimeMillis(); + } + return len == 0; +} + bool static Socks5(string strDest, int port, SOCKET& hSocket) { LogPrintf("SOCKS5 connecting %s\n", strDest); @@ -243,7 +303,7 @@ bool static Socks5(string strDest, int port, SOCKET& hSocket) return error("Error sending to proxy"); } char pchRet1[2]; - if (recv(hSocket, pchRet1, 2, 0) != 2) + if (!InterruptibleRecv(pchRet1, 2, SOCKS5_RECV_TIMEOUT, hSocket)) { CloseSocket(hSocket); return error("Error reading proxy response"); @@ -266,7 +326,7 @@ bool static Socks5(string strDest, int port, SOCKET& hSocket) return error("Error sending to proxy"); } char pchRet2[4]; - if (recv(hSocket, pchRet2, 4, 0) != 4) + if (!InterruptibleRecv(pchRet2, 4, SOCKS5_RECV_TIMEOUT, hSocket)) { CloseSocket(hSocket); return error("Error reading proxy response"); @@ -300,27 +360,27 @@ bool static Socks5(string strDest, int port, SOCKET& hSocket) char pchRet3[256]; switch (pchRet2[3]) { - case 0x01: ret = recv(hSocket, pchRet3, 4, 0) != 4; break; - case 0x04: ret = recv(hSocket, pchRet3, 16, 0) != 16; break; + case 0x01: ret = InterruptibleRecv(pchRet3, 4, SOCKS5_RECV_TIMEOUT, hSocket); break; + case 0x04: ret = InterruptibleRecv(pchRet3, 16, SOCKS5_RECV_TIMEOUT, hSocket); break; case 0x03: { - ret = recv(hSocket, pchRet3, 1, 0) != 1; - if (ret) { + ret = InterruptibleRecv(pchRet3, 1, SOCKS5_RECV_TIMEOUT, hSocket); + if (!ret) { CloseSocket(hSocket); return error("Error reading from proxy"); } int nRecv = pchRet3[0]; - ret = recv(hSocket, pchRet3, nRecv, 0) != nRecv; + ret = InterruptibleRecv(pchRet3, nRecv, SOCKS5_RECV_TIMEOUT, hSocket); break; } default: CloseSocket(hSocket); return error("Error: malformed proxy response"); } - if (ret) + if (!ret) { CloseSocket(hSocket); return error("Error reading from proxy"); } - if (recv(hSocket, pchRet3, 2, 0) != 2) + if (!InterruptibleRecv(pchRet3, 2, SOCKS5_RECV_TIMEOUT, hSocket)) { CloseSocket(hSocket); return error("Error reading from proxy"); @@ -360,10 +420,7 @@ bool static ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRe // WSAEINVAL is here because some legacy version of winsock uses it if (nErr == WSAEINPROGRESS || nErr == WSAEWOULDBLOCK || nErr == WSAEINVAL) { - struct timeval timeout; - timeout.tv_sec = nTimeout / 1000; - timeout.tv_usec = (nTimeout % 1000) * 1000; - + struct timeval timeout = MillisToTimeval(nTimeout); fd_set fdset; FD_ZERO(&fdset); FD_SET(hSocket, &fdset); @@ -410,11 +467,6 @@ bool static ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRe } } - // This is required when using SOCKS5 proxy! - // CNode::ConnectNode turns the socket back to non-blocking. - if (!SetSocketNonBlocking(hSocket, false)) - return error("ConnectSocketDirectly: Setting socket to blocking failed, error %s\n", NetworkErrorString(WSAGetLastError())); - hSocketRet = hSocket; return true; }