fix(tcp): resolve, connect, bind and send failures were silent or wrong

The HTTP/1.1 stack sits directly on these two classes and each of these
bit it:

- gethostbyname() returning null on an unresolvable host was dereferenced
  straight into a crash, and it is not thread safe; use getaddrinfo.
- A failed socket()/connect() only printed to stderr and handed back an
  unusable ClientTCP, so the real error surfaced much later as an
  unrelated errno from send().
- send() was assumed to accept everything it was offered. It does not
  once a buffer outgrows the socket's send buffer, which silently
  truncated multi-megabyte bodies. Loop, and pass MSG_NOSIGNAL so a
  vanished peer raises EPIPE instead of killing the process.
- ClientTCP's move constructor closed the socket it had just taken
  ownership of, and both it and the destructor tested `socketid != 1`
  where they meant `!= -1`.
- ListenerTCP ignored bind()'s result, leaving a listener that accepted
  nothing with no explanation, and did not set SO_REUSEADDR, so a
  restart hit EADDRINUSE for the length of TIME_WAIT.

accept() failing during Stop() is expected and no longer logged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

implementations/Crafter.Network-ClientTCP.cpp

@@ -31,11 +31,22 @@ ClientTCP::ClientTCP(int socketid) : socketid(socketid)
 
 ClientTCP::ClientTCP(const char* hostName, std::uint16_t port)
 {
-	host = gethostbyname(hostName);
-	serv_addr.sin_family = AF_INET;
-	serv_addr.sin_port = htons(port);
-	serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
-	bzero(&(serv_addr.sin_zero),8);
+	// getaddrinfo rather than gethostbyname: the latter is not thread safe,
+	// and it signals failure by returning null — which was then dereferenced
+	// straight into a crash on any unresolvable host.
+	addrinfo hints{};
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_STREAM;
+	addrinfo* resolved = nullptr;
+	const std::string service = std::to_string(port);
+	const int status = getaddrinfo(hostName, service.c_str(), &hints, &resolved);
+	if (status != 0 || resolved == nullptr) {
+		throw std::runtime_error(std::string("Could not resolve host '") + hostName + "': "
+		                         + gai_strerror(status));
+	}
+	host = nullptr;
+	serv_addr = *reinterpret_cast<sockaddr_in*>(resolved->ai_addr);
+	freeaddrinfo(resolved);
 
     Connect();
 }
@@ -45,17 +56,16 @@ ClientTCP::ClientTCP(std::string hostName, std::uint16_t port): ClientTCP(hostNa
 
 }
 
+// The moved-from object gives up ownership; the socket itself stays open —
+// closing it here (as this used to) meant moving a ClientTCP silently
+// dropped the connection it was carrying.
 ClientTCP::ClientTCP(ClientTCP&& other) noexcept : socketid(other.socketid) {
-    if(socketid != 1) {
-        shutdown(socketid, SHUT_RDWR);
-	    close(socketid);
-    }
     other.socketid = -1;
 }
 
 ClientTCP::~ClientTCP()
 {
-    if(socketid != 1) {
+    if(socketid != -1) {
         shutdown(socketid, SHUT_RDWR);
 	    close(socketid);
     }
@@ -63,11 +73,17 @@ ClientTCP::~ClientTCP()
 
 void ClientTCP::Connect() {
     if((socketid = socket(AF_INET, SOCK_STREAM, 0)) == -1){
-        std::cerr << "Could not open socket" << std::endl;
+        throw std::runtime_error(std::string("Could not open socket: ") + std::strerror(errno));
 	}
 
 	if(connect(socketid,(sockaddr*)&serv_addr, sizeof(sockaddr)) == -1){
-        std::cerr << "Could not connect to server" << std::endl;
+        // Report the failure instead of handing back a socket that is not
+        // connected to anything — every later send/recv on it would fail
+        // with a far less obvious error.
+        const std::string reason = std::strerror(errno);
+        close(socketid);
+        socketid = -1;
+        throw std::runtime_error("Could not connect to server: " + reason);
 	}
 }
 
@@ -78,13 +94,21 @@ void ClientTCP::Stop() {
 }
 
 void ClientTCP::Send(const void* buffer, std::uint32_t size) const {
-    int status = send(socketid, reinterpret_cast<const char*>(buffer), size, 0);
-
+    // send() is free to accept less than it was offered, and does so
+    // routinely once a buffer outgrows the socket's send buffer — a
+    // multi-megabyte HTTP body, say. Loop until it is all handed over.
+    const char* data = reinterpret_cast<const char*>(buffer);
+    std::uint32_t sent = 0;
+    while (sent < size) {
+        const auto status = send(socketid, data + sent, size - sent, MSG_NOSIGNAL);
         if (status == 0) {
             throw SocketClosedException();
         } else if (status < 0) {
+            if (errno == EINTR) continue;
             throw std::runtime_error(std::strerror(errno));
         }
+        sent += static_cast<std::uint32_t>(status);
+    }
 }
 std::vector<char> ClientTCP::RecieveSync(std::uint32_t bufferSize) const {
     std::vector<char> totalBuffer(bufferSize);

implementations/Crafter.Network-ListenerTCP.cpp

@@ -12,6 +12,7 @@ module;
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <strings.h>
+#include <cerrno>
 
 module Crafter.Network:ListenerTCP_impl;
 import :ListenerTCP;
@@ -32,8 +33,26 @@ ListenerTCP::ListenerTCP(std::uint16_t port, std::function<void(ClientTCP*)> con
     {
         throw std::runtime_error("Error establishing the server socket");
     }
-	int bindStatus = bind(s, (struct sockaddr*) &servAddr, sizeof(servAddr));
-	listen(s, 5);
+    // Without SO_REUSEADDR the port stays unbindable for the length of
+    // TIME_WAIT after a restart, which turns "restart the server" into a
+    // minute of failed binds.
+    int reuse = 1;
+    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
+
+	if(bind(s, (struct sockaddr*) &servAddr, sizeof(servAddr)) < 0) {
+        // Ignoring this left the listener silently accepting nothing at
+        // all, with no hint as to why.
+        const std::string reason = std::strerror(errno);
+        close(s);
+        s = -1;
+        throw std::runtime_error("Could not bind port " + std::to_string(port) + ": " + reason);
+    }
+	if(listen(s, 128) < 0) {
+        const std::string reason = std::strerror(errno);
+        close(s);
+        s = -1;
+        throw std::runtime_error("Could not listen on port " + std::to_string(port) + ": " + reason);
+    }
 }
 
 void ListenerTCP::Stop() {
@@ -52,7 +71,9 @@ void ListenerTCP::ListenSyncSync() {
 			connectCallback(new ClientTCP(client));
             this->totalClientCounter++;
 		}
-		else {
+		else if (running) {
+			// accept() also fails once on the way out, when Stop() closes
+			// the listening socket — that one is not worth reporting.
 			std::cerr << "Error accepting request from client!" << std::endl;
 		}
 	}
@@ -67,7 +88,7 @@ void ListenerTCP::ListenSyncAsync() {
 			ThreadPool::Enqueue([this, client]() {connectCallback(new ClientTCP(client)); });
             this->totalClientCounter++;
 		}
-		else {
+		else if (running) {
 			std::cerr << "Error accepting request from client!" << std::endl;
 		}
 	}
@@ -83,7 +104,7 @@ void ListenerTCP::ListenAsyncSync() {
 			    connectCallback(new ClientTCP(client));
                 this->totalClientCounter++;
 		    }
-		    else {
+		    else if (running) {
 			    std::cerr << "Error accepting request from client!" << std::endl;
 		    }
 	    }
@@ -100,7 +121,7 @@ void ListenerTCP::ListenAsyncAsync() {
                 ThreadPool::Enqueue([this, client]() {connectCallback(new ClientTCP(client)); });
                 this->totalClientCounter++;
 		    }
-		    else {
+		    else if (running) {
 			    std::cerr << "Error accepting request from client!" << std::endl;
 		    }
 	    }