#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/tcp.h>   // For TCP_MAXSEG

#define PORT 9090
#define BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in server_addr;
    char buffer[BUFFER_SIZE];
    int mss;

    // Create socket
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("Socket creation failed");
        exit(EXIT_FAILURE);
    }

    // Server details
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(PORT);
    server_addr.sin_addr.s_addr = inet_addr("192.168.2.1");

    // Connect to server
    if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("Connection failed");
        close(sockfd);
        exit(EXIT_FAILURE);
    }

    // Get default MSS
    socklen_t optlen = sizeof(mss);
    if (getsockopt(sockfd, IPPROTO_TCP, TCP_MAXSEG, &mss, &optlen) == 0) {
        printf("Client: Default TCP_MAXSEG (MSS) = %d bytes\n", mss);
    }

    // Send message to server
    char *msg = "Hello Server";
    send(sockfd, msg, strlen(msg), 0);

    // Receive reply
    int n = read(sockfd, buffer, sizeof(buffer));
    buffer[n] = '\0';
    printf("Client received: %s\n", buffer);

    close(sockfd);
    return 0;
}