tinyserv.c

// Servidor TCP mínimo — escucha en puerto 31337, saluda y hace eco.
// Ctrl+C para parar.
#include "../0x260/0x265_hacking.h"
#include <netinet/in.h>

#define PORT 31337

int main(void) {
    int sockfd, new_sockfd, yes = 1, recv_length;
    struct sockaddr_in host_addr, client_addr;
    socklen_t sin_size;
    char buffer[1024];

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) fatal("socket");
    setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));

    host_addr.sin_family      = AF_INET;
    host_addr.sin_port        = htons(PORT);
    host_addr.sin_addr.s_addr = INADDR_ANY;
    memset(&(host_addr.sin_zero), 0, 8);

    if (bind(sockfd, (struct sockaddr *) &host_addr, sizeof(struct sockaddr)) == -1)
        fatal("bind");
    if (listen(sockfd, 5) == -1) fatal("listen");

    printf("[*] Escuchando en puerto %d...\n", PORT);
    while (1) {
        sin_size = sizeof(struct sockaddr_in);
        new_sockfd = accept(sockfd, (struct sockaddr *) &client_addr, &sin_size);
        if (new_sockfd == -1) { perror("accept"); continue; }
        printf("[+] Conexión de %s:%d\n",
               inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

        send(new_sockfd, "Hola desde tinyserv\n", 20, 0);
        recv_length = recv(new_sockfd, buffer, sizeof(buffer), 0);
        while (recv_length > 0) {
            printf("[recv] %.*s", recv_length, buffer);
            send(new_sockfd, buffer, recv_length, 0);   // eco
            recv_length = recv(new_sockfd, buffer, sizeof(buffer), 0);
        }
        close(new_sockfd);
    }
    close(sockfd);
    return 0;
}