76 lines
2.0 KiB
C
76 lines
2.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#define PORT 8080
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#define BUFFER_SIZE 1024
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int main() {
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int server_fd, new_socket;
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struct sockaddr_in address;
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int opt = 1;
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int addrlen = sizeof(address);
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char buffer[BUFFER_SIZE] = {0};
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// 1. Create socket file descriptor
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// AF_INET: IPv4, SOCK_STREAM: TCP
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if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
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perror("socket failed");
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exit(EXIT_FAILURE);
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}
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// 2. Attach socket to the port 8080
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// SO_REUSEADDR allows restarting the server immediately after closing
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if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
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perror("setsockopt");
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exit(EXIT_FAILURE);
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}
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address.sin_family = AF_INET;
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address.sin_addr.s_addr = INADDR_ANY; // Listen on all interfaces
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address.sin_port = htons(PORT);
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// Bind
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if (bind(server_fd, (struct sockaddr *)&address, sizeof(address)) < 0) {
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perror("bind failed");
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exit(EXIT_FAILURE);
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}
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// 3. Listen for incoming connections
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if (listen(server_fd, 3) < 0) {
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perror("listen");
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exit(EXIT_FAILURE);
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}
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printf("TCP Server listening on port %d...\n", PORT);
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// 4. Accept connection
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if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen)) < 0) {
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perror("accept");
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exit(EXIT_FAILURE);
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}
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printf("Client connected.\n");
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// 5. Receive data
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int valread = read(new_socket, buffer, BUFFER_SIZE);
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if (valread > 0) {
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printf("Received %d bytes: %s\n", valread, buffer);
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// 6. Send response (Echo length or simple ack)
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char response[BUFFER_SIZE];
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snprintf(response, BUFFER_SIZE, "Server received %d bytes", valread);
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send(new_socket, response, strlen(response), 0);
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printf("Response sent to client.\n");
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}
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// 7. Close socket
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close(new_socket);
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close(server_fd);
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return 0;
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}
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