Merge #11363: net: Split socket create/connect

3830b6e net: use CreateSocket for binds (Cory Fields)
df3bcf8 net: pass socket closing responsibility up to caller for outgoing connections (Cory Fields)
9e3b2f5 net: Move IsSelectableSocket check into socket creation (Cory Fields)
1729c29 net: split socket creation out of connection (Cory Fields)

Pull request description:

  Requirement for #11227.

  We'll need to create sockets and perform the actual connect in separate steps, so break them up.

  #11227 adds an RAII wrapper around connection attempts, as a belt-and-suspenders in case a CloseSocket is missed.

Tree-SHA512: de675bb718cc56d68893c303b8057ca062c7431eaa17ae7c4829caed119fa3f15b404d8f52aca22a6bca6e73a26fb79e898b335d090ab015bf6456cf417fc694

3 files changed, 63 insertions, 82 deletions

diff --git a/src/net.cpp b/src/net.cpp
index c0f31e83dd..23bf640472 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -415,39 +415,48 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
     if (addrConnect.IsValid()) {
         bool proxyConnectionFailed = false;
 
-        if (GetProxy(addrConnect.GetNetwork(), proxy))
+        if (GetProxy(addrConnect.GetNetwork(), proxy)) {
+            hSocket = CreateSocket(proxy.proxy);
+            if (hSocket == INVALID_SOCKET) {
+                return nullptr;
+            }
             connected = ConnectThroughProxy(proxy, addrConnect.ToStringIP(), addrConnect.GetPort(), hSocket, nConnectTimeout, &proxyConnectionFailed);
-        else // no proxy needed (none set for target network)
+        } else {
+            // no proxy needed (none set for target network)
+            hSocket = CreateSocket(addrConnect);
+            if (hSocket == INVALID_SOCKET) {
+                return nullptr;
+            }
             connected = ConnectSocketDirectly(addrConnect, hSocket, nConnectTimeout);
+        }
         if (!proxyConnectionFailed) {
             // If a connection to the node was attempted, and failure (if any) is not caused by a problem connecting to
             // the proxy, mark this as an attempt.
             addrman.Attempt(addrConnect, fCountFailure);
         }
     } else if (pszDest && GetNameProxy(proxy)) {
+        hSocket = CreateSocket(proxy.proxy);
+        if (hSocket == INVALID_SOCKET) {
+            return nullptr;
+        }
         std::string host;
         int port = default_port;
         SplitHostPort(std::string(pszDest), port, host);
         connected = ConnectThroughProxy(proxy, host, port, hSocket, nConnectTimeout, nullptr);
     }
-    if (connected) {
-        if (!IsSelectableSocket(hSocket)) {
-            LogPrintf("Cannot create connection: non-selectable socket created (fd >= FD_SETSIZE ?)\n");
-            CloseSocket(hSocket);
-            return nullptr;
-        }
-
-        // Add node
-        NodeId id = GetNewNodeId();
-        uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
-        CAddress addr_bind = GetBindAddress(hSocket);
-        CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addrConnect, CalculateKeyedNetGroup(addrConnect), nonce, addr_bind, pszDest ? pszDest : "", false);
-        pnode->AddRef();
-
-        return pnode;
+    if (!connected) {
+        CloseSocket(hSocket);
+        return nullptr;
     }
 
-    return nullptr;
+    // Add node
+    NodeId id = GetNewNodeId();
+    uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
+    CAddress addr_bind = GetBindAddress(hSocket);
+    CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addrConnect, CalculateKeyedNetGroup(addrConnect), nonce, addr_bind, pszDest ? pszDest : "", false);
+    pnode->AddRef();
+
+    return pnode;
 }
 
 void CConnman::DumpBanlist()
@@ -2056,44 +2065,21 @@ bool CConnman::BindListenPort(const CService &addrBind, std::string& strError, b
         return false;
     }
 
-    SOCKET hListenSocket = socket(((struct sockaddr*)&sockaddr)->sa_family, SOCK_STREAM, IPPROTO_TCP);
+    SOCKET hListenSocket = CreateSocket(addrBind);
     if (hListenSocket == INVALID_SOCKET)
     {
         strError = strprintf("Error: Couldn't open socket for incoming connections (socket returned error %s)", NetworkErrorString(WSAGetLastError()));
         LogPrintf("%s\n", strError);
         return false;
     }
-    if (!IsSelectableSocket(hListenSocket))
-    {
-        strError = "Error: Couldn't create a listenable socket for incoming connections";
-        LogPrintf("%s\n", strError);
-        return false;
-    }
-
-
 #ifndef WIN32
-#ifdef SO_NOSIGPIPE
-    // Different way of disabling SIGPIPE on BSD
-    setsockopt(hListenSocket, SOL_SOCKET, SO_NOSIGPIPE, (void*)&nOne, sizeof(int));
-#endif
     // Allow binding if the port is still in TIME_WAIT state after
     // the program was closed and restarted.
     setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (void*)&nOne, sizeof(int));
-    // Disable Nagle's algorithm
-    setsockopt(hListenSocket, IPPROTO_TCP, TCP_NODELAY, (void*)&nOne, sizeof(int));
 #else
     setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (const char*)&nOne, sizeof(int));
-    setsockopt(hListenSocket, IPPROTO_TCP, TCP_NODELAY, (const char*)&nOne, sizeof(int));
 #endif
 
-    // Set to non-blocking, incoming connections will also inherit this
-    if (!SetSocketNonBlocking(hListenSocket, true)) {
-        CloseSocket(hListenSocket);
-        strError = strprintf("BindListenPort: Setting listening socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError()));
-        LogPrintf("%s\n", strError);
-        return false;
-    }
-
     // some systems don't have IPV6_V6ONLY but are always v6only; others do have the option
     // and enable it by default or not. Try to enable it, if possible.
     if (addrBind.IsIPv6()) {
diff --git a/src/netbase.cpp b/src/netbase.cpp
index da3729b286..f4232fc42a 100644
--- a/src/netbase.cpp
+++ b/src/netbase.cpp
@@ -313,12 +313,11 @@ std::string Socks5ErrorString(uint8_t err)
 }
 
 /** Connect using SOCKS5 (as described in RFC1928) */
-static bool Socks5(const std::string& strDest, int port, const ProxyCredentials *auth, SOCKET& hSocket)
+static bool Socks5(const std::string& strDest, int port, const ProxyCredentials *auth, const SOCKET& hSocket)
 {
     IntrRecvError recvr;
     LogPrint(BCLog::NET, "SOCKS5 connecting %s\n", strDest);
     if (strDest.size() > 255) {
-        CloseSocket(hSocket);
         return error("Hostname too long");
     }
     // Accepted authentication methods
@@ -334,17 +333,14 @@ static bool Socks5(const std::string& strDest, int port, const ProxyCredentials
     }
     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");
     }
     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] != SOCKSVersion::SOCKS5) {
-        CloseSocket(hSocket);
         return error("Proxy failed to initialize");
     }
     if (pchRet1[1] == SOCKS5Method::USER_PASS && auth) {
@@ -359,23 +355,19 @@ static bool Socks5(const std::string& strDest, int port, const ProxyCredentials
         vAuth.insert(vAuth.end(), auth->password.begin(), auth->password.end());
         ret = send(hSocket, (const char*)vAuth.data(), vAuth.size(), MSG_NOSIGNAL);
         if (ret != (ssize_t)vAuth.size()) {
-            CloseSocket(hSocket);
             return error("Error sending authentication to proxy");
         }
         LogPrint(BCLog::PROXY, "SOCKS5 sending proxy authentication %s:%s\n", auth->username, auth->password);
         uint8_t pchRetA[2];
         if ((recvr = InterruptibleRecv(pchRetA, 2, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) {
-            CloseSocket(hSocket);
             return error("Error reading proxy authentication response");
         }
         if (pchRetA[0] != 0x01 || pchRetA[1] != 0x00) {
-            CloseSocket(hSocket);
             return error("Proxy authentication unsuccessful");
         }
     } else if (pchRet1[1] == SOCKS5Method::NOAUTH) {
         // Perform no authentication
     } else {
-        CloseSocket(hSocket);
         return error("Proxy requested wrong authentication method %02x", pchRet1[1]);
     }
     std::vector<uint8_t> vSocks5;
@@ -389,12 +381,10 @@ static bool Socks5(const std::string& strDest, int port, const ProxyCredentials
     vSocks5.push_back((port >> 0) & 0xFF);
     ret = send(hSocket, (const char*)vSocks5.data(), vSocks5.size(), MSG_NOSIGNAL);
     if (ret != (ssize_t)vSocks5.size()) {
-        CloseSocket(hSocket);
         return error("Error sending to proxy");
     }
     uint8_t pchRet2[4];
     if ((recvr = InterruptibleRecv(pchRet2, 4, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) {
-        CloseSocket(hSocket);
         if (recvr == IntrRecvError::Timeout) {
             /* If a timeout happens here, this effectively means we timed out while connecting
              * to the remote node. This is very common for Tor, so do not print an
@@ -405,17 +395,14 @@ static bool Socks5(const std::string& strDest, int port, const ProxyCredentials
         }
     }
     if (pchRet2[0] != SOCKSVersion::SOCKS5) {
-        CloseSocket(hSocket);
         return error("Proxy failed to accept request");
     }
     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) { // Reserved field must be 0
-        CloseSocket(hSocket);
         return error("Error: malformed proxy response");
     }
     uint8_t pchRet3[256];
@@ -427,41 +414,42 @@ static bool Socks5(const std::string& strDest, int port, const ProxyCredentials
         {
             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;
         }
-        default: CloseSocket(hSocket); return error("Error: malformed proxy response");
+        default: return error("Error: malformed proxy response");
     }
     if (recvr != IntrRecvError::OK) {
-        CloseSocket(hSocket);
         return error("Error reading from proxy");
     }
     if ((recvr = InterruptibleRecv(pchRet3, 2, SOCKS5_RECV_TIMEOUT, hSocket)) != IntrRecvError::OK) {
-        CloseSocket(hSocket);
         return error("Error reading from proxy");
     }
     LogPrint(BCLog::NET, "SOCKS5 connected %s\n", strDest);
     return true;
 }
 
-bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int nTimeout)
+SOCKET CreateSocket(const CService &addrConnect)
 {
-    hSocketRet = INVALID_SOCKET;
-
     struct sockaddr_storage sockaddr;
     socklen_t len = sizeof(sockaddr);
     if (!addrConnect.GetSockAddr((struct sockaddr*)&sockaddr, &len)) {
-        LogPrintf("Cannot connect to %s: unsupported network\n", addrConnect.ToString());
-        return false;
+        LogPrintf("Cannot create socket for %s: unsupported network\n", addrConnect.ToString());
+        return INVALID_SOCKET;
     }
 
     SOCKET hSocket = socket(((struct sockaddr*)&sockaddr)->sa_family, SOCK_STREAM, IPPROTO_TCP);
     if (hSocket == INVALID_SOCKET)
-        return false;
+        return INVALID_SOCKET;
+
+    if (!IsSelectableSocket(hSocket)) {
+        CloseSocket(hSocket);
+        LogPrintf("Cannot create connection: non-selectable socket created (fd >= FD_SETSIZE ?)\n");
+        return INVALID_SOCKET;
+    }
 
 #ifdef SO_NOSIGPIPE
     int set = 1;
@@ -475,9 +463,23 @@ bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int
     // Set to non-blocking
     if (!SetSocketNonBlocking(hSocket, true)) {
         CloseSocket(hSocket);
-        return error("ConnectSocketDirectly: Setting socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError()));
+        LogPrintf("ConnectSocketDirectly: Setting socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError()));
     }
+    return hSocket;
+}
 
+bool ConnectSocketDirectly(const CService &addrConnect, const SOCKET& hSocket, int nTimeout)
+{
+    struct sockaddr_storage sockaddr;
+    socklen_t len = sizeof(sockaddr);
+    if (hSocket == INVALID_SOCKET) {
+        LogPrintf("Cannot connect to %s: invalid socket\n", addrConnect.ToString());
+        return false;
+    }
+    if (!addrConnect.GetSockAddr((struct sockaddr*)&sockaddr, &len)) {
+        LogPrintf("Cannot connect to %s: unsupported network\n", addrConnect.ToString());
+        return false;
+    }
     if (connect(hSocket, (struct sockaddr*)&sockaddr, len) == SOCKET_ERROR)
     {
         int nErr = WSAGetLastError();
@@ -492,13 +494,11 @@ bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int
             if (nRet == 0)
             {
                 LogPrint(BCLog::NET, "connection to %s timeout\n", addrConnect.ToString());
-                CloseSocket(hSocket);
                 return false;
             }
             if (nRet == SOCKET_ERROR)
             {
                 LogPrintf("select() for %s failed: %s\n", addrConnect.ToString(), NetworkErrorString(WSAGetLastError()));
-                CloseSocket(hSocket);
                 return false;
             }
             socklen_t nRetSize = sizeof(nRet);
@@ -509,13 +509,11 @@ bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int
 #endif
             {
                 LogPrintf("getsockopt() for %s failed: %s\n", addrConnect.ToString(), NetworkErrorString(WSAGetLastError()));
-                CloseSocket(hSocket);
                 return false;
             }
             if (nRet != 0)
             {
                 LogPrintf("connect() to %s failed after select(): %s\n", addrConnect.ToString(), NetworkErrorString(nRet));
-                CloseSocket(hSocket);
                 return false;
             }
         }
@@ -526,12 +524,9 @@ bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int
 #endif
         {
             LogPrintf("connect() to %s failed: %s\n", addrConnect.ToString(), NetworkErrorString(WSAGetLastError()));
-            CloseSocket(hSocket);
             return false;
         }
     }
-
-    hSocketRet = hSocket;
     return true;
 }
 
@@ -583,9 +578,8 @@ bool IsProxy(const CNetAddr &addr) {
     return false;
 }
 
-bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed)
+bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, const SOCKET& hSocket, int nTimeout, bool *outProxyConnectionFailed)
 {
-    SOCKET hSocket = INVALID_SOCKET;
     // first connect to proxy server
     if (!ConnectSocketDirectly(proxy.proxy, hSocket, nTimeout)) {
         if (outProxyConnectionFailed)
@@ -597,14 +591,14 @@ bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int
         ProxyCredentials random_auth;
         static std::atomic_int counter(0);
         random_auth.username = random_auth.password = strprintf("%i", counter++);
-        if (!Socks5(strDest, (unsigned short)port, &random_auth, hSocket))
+        if (!Socks5(strDest, (unsigned short)port, &random_auth, hSocket)) {
             return false;
+        }
     } else {
-        if (!Socks5(strDest, (unsigned short)port, 0, hSocket))
+        if (!Socks5(strDest, (unsigned short)port, 0, hSocket)) {
             return false;
+        }
     }
-
-    hSocketRet = hSocket;
     return true;
 }
 bool LookupSubNet(const char* pszName, CSubNet& ret)
diff --git a/src/netbase.h b/src/netbase.h
index 0a07be87b7..c89bd5b88f 100644
--- a/src/netbase.h
+++ b/src/netbase.h
@@ -51,8 +51,9 @@ bool Lookup(const char *pszName, CService& addr, int portDefault, bool fAllowLoo
 bool Lookup(const char *pszName, std::vector<CService>& vAddr, int portDefault, bool fAllowLookup, unsigned int nMaxSolutions);
 CService LookupNumeric(const char *pszName, int portDefault = 0);
 bool LookupSubNet(const char *pszName, CSubNet& subnet);
-bool ConnectSocketDirectly(const CService &addrConnect, SOCKET& hSocketRet, int nTimeout);
-bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed);
+SOCKET CreateSocket(const CService &addrConnect);
+bool ConnectSocketDirectly(const CService &addrConnect, const SOCKET& hSocketRet, int nTimeout);
+bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, const SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed);
 /** Return readable error string for a network error code */
 std::string NetworkErrorString(int err);
 /** Close socket and set hSocket to INVALID_SOCKET */