Simple echo client for linux

echo_client.c

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
 
int main(int argc, char *argv[]) {
    const char *SERVER_IP = "127.0.0.1";
 
    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if (fd == -1) {
        fprintf(stderr, "Error on socket creation.\n");
        return 1;
    }
 
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(8080);
 
    if (inet_pton(AF_INET, SERVER_IP, &(server_addr.sin_addr)) == -1) {
        fprintf(stderr, "Invalid server IP address.\n");
        return 1;
    }

    struct timeval tv;
    tv.tv_sec = 30; // 30 seconds timeout for send, revc
    tv.tv_usec = 0;

    if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO,
        (char *) &tv, sizeof(struct timeval)) == -1) {
        fprintf(stderr, "Error on setting socket receive timeout.\n");
        return 1;
    }
 
    if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO,
            (char *) &tv, sizeof(struct timeval)) == -1) {
        fprintf(stderr, "Error on setting socket send timeout.\n");
        return 1;
    }

    if (connect(fd, (struct sockaddr *) &server_addr,
            sizeof(server_addr)) == -1) {
        fprintf(stderr, "Couldn't connect to server.\n");
        return 1;
    }
 
    char message[] = "Test message\n";
    int data_len = sizeof(message);
    void *buf_pt = message;
    int slen;
    // Send message
    while ((slen = send(fd, buf_pt, data_len, 0)) != 0) {
        if (slen == -1) {
            fprintf(stderr, "Error on sending data.\n");
            close(fd);
            return 1;
        }
        data_len -= slen;
        buf_pt += slen;
    }
 
    // Receive message
    const int BUF_LEN = 2048;
    char buf[BUF_LEN];
    int rlen;
    int recv_data_len = 0;
    while (recv_data_len < sizeof(message)
            && (rlen = recv(fd, buf, BUF_LEN, 0)) != 0) {

        if (rlen == -1) {
            fprintf(stderr, "Error on receiving data.\n");
            close(fd);
            return 1;
        }

        fwrite(buf, 1, rlen, stdout);
        recv_data_len += rlen;
    }
 
    close(fd);
 
    return 0;
}