server upd

added python client

src/constants.hpp

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+
+const uint32_t k_max_message_size = 4096;

src/net_util.cpp

@@ -0,0 +1,37 @@
+#include "net_util.hpp"
+#include <assert.h>
+#include <string>
+
+
+int32_t read_full(int connectionfd, void* buf, size_t len) {
+    auto buffer = static_cast<char*>(buf);
+    while (len > 0) {
+        ssize_t rv = ::read(connectionfd, buffer, len);
+        if (rv == 0) {
+            return -1;
+        }
+        if (rv < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+            return -1;
+        }
+        buffer += rv;
+        len -= static_cast<size_t>(rv);
+    }
+    return 0;
+}
+
+int32_t write_all(int connectionfd, const void* buf, size_t len) {
+    auto* buffer = static_cast<const char*>(buf);
+    while (len > 0) {
+        ssize_t rv = ::write(connectionfd, buffer, len);
+        if (rv <= 0) {
+            if (rv < 0 && errno == EINTR) continue;
+            return -1;
+        }
+        buffer += rv;
+        len -= static_cast<size_t>(rv);
+    }
+    return 0;
+}

src/net_util.hpp

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdint.h>
+#include <unistd.h>
+
+int32_t read_full(int connectionfd, void* buf, size_t len);
+int32_t write_all(int connectionfd, const void* buf, size_t len);

src/server.cpp

@@ -1,9 +1,20 @@
-#include "server.hpp"
-#include <iostream>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <unistd.h>
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netinet/ip.h>
+#include <iostream>
+
+#include "server.hpp"
+#include "net_util.hpp"
+#include "constants.hpp"
+#include "utils.hpp"
+
 
 Server::Server(const Config& config)
     : address(config.get_address()), port(config.get_port()), sockfd(-1) {
@@ -43,18 +54,41 @@ void Server::setup() {
     std::cout << "Server started on " << address << ":" << port << "\n";
 }
 
-void Server::handle_connection(int connectionfd) {
-    char rbuf[64] = {};
-    ssize_t n = read(connectionfd, rbuf, sizeof(rbuf) - 1);
-    if (n < 0) {
-        std::cerr << "Error reading client packet\n";
-        return;
+int32_t Server::handle_connection(int connectionfd) {
+    std::cout << "Waiting for data from " << connectionfd << "\n";
+
+    uint32_t len_net = 0;
+    errno = 0;
+    if (read_full(connectionfd, &len_net, sizeof(len_net)) != 0) {
+        print_error(errno == 0 ? "EOF from client" : "Error reading length");
+        return -1;
     }
-    std::cout << "Client says: " << std::string(rbuf, n) << "\n";
-    ssize_t written = write(connectionfd, "Hello, client!\n", 14);
-    if (written < 0) {
-        std::cerr << "Error writing to client\n";
+
+    uint32_t len = ntohl(len_net);
+
+    if (len > k_max_message_size) {
+        print_error("Message length is too long");
+        std::cerr << len << " > " << k_max_message_size << "\n";
+        return -1;
     }
+
+    std::string message(len, '\0');
+    if (len > 0) {
+        if (read_full(connectionfd, message.data(), len) != 0) {
+            print_error("Error reading payload");
+            return -1;
+        }
+    }
+
+    std::cout << "Client says: " << message << "\n";
+
+    const std::string reply = "world";
+    uint32_t reply_len_net = htonl(static_cast<uint32_t>(reply.size()));
+
+    if (write_all(connectionfd, &reply_len_net, sizeof(reply_len_net)) != 0) return -1;
+    if (write_all(connectionfd, reply.data(), reply.size()) != 0) return -1;
+
+    return 0;
 }
 
 void Server::run() {
@@ -67,7 +101,14 @@ void Server::run() {
         if (connectionfd < 0) {
             continue;
         }
-        handle_connection(connectionfd);
+        std::cout << "Accepted connection from " << connectionfd << "\n";
+        while (true) {
+            int32_t err = handle_connection(connectionfd);
+            if (err) {
+                break;
+            }
+        }
+        std::cout << "Closing connection from " << connectionfd << "\n";
         close(connectionfd);
     }
 }

src/server.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <stdint.h>
 #include "config.hpp"
 
 class Server {
@@ -15,6 +16,6 @@ private:
     std::string address;
     int port;
 
-    void handle_connection(int connectionfd);
+    int32_t handle_connection(int connectionfd);
     void setup();
 };

src/utils.cpp

@@ -7,3 +7,7 @@ void stop_program(int signum) {
     std::cout << "Exiting program...\n";
     exit(signum); 
 }
+
+void print_error(const std::string& msg) {
+    std::cerr << msg << ": " << std::strerror(errno) << "\n";
+}

src/utils.hpp

@@ -1,6 +1,8 @@
 #pragma once
 
 #include <netinet/in.h>
+#include <string>
 
 void stop_program(int signum);
+void print_error(const std::string& msg);