/*
 * Copyright 2008-2010, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Yin Qiu
 */


#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>


#define MAX_LENGTH 4096


extern const char* __progname;


int
main(int argc, char** argv)
{
        if (argc < 2) {
                fprintf(stderr, "Usage: %s <host> [<port>]\n"
                        "Sends a UDP datagram to the specified target.\n"
                        "<port> defaults to 9999.\n", __progname);
                return 1;
        }

        struct hostent* host = gethostbyname(argv[1]);
        if (host == NULL) {
                perror("gethostbyname");
                return 1;
        }

        uint16_t port = 9999;
        if (argc > 2)
                port = atol(argv[2]);

        struct sockaddr_in serverAddr;
        memset(&serverAddr, 0, sizeof(struct sockaddr_in));
        serverAddr.sin_family = AF_INET;
        serverAddr.sin_port = htons(port);
        serverAddr.sin_addr = *((struct in_addr*)host->h_addr);

        int sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        // We need to call connect() to receive async ICMP errors
        if (connect(sockfd, (struct sockaddr*)&serverAddr,
                        sizeof(struct sockaddr_in)) < 0) {
                fprintf(stderr, "Calling connect() on UDP socket failed: %s\n",
                        strerror(errno));
                return 1;
        }

        const char* string = "Hello";
        ssize_t bytes = write(sockfd, string, strlen(string));
        if (bytes < 0) {
                fprintf(stderr, "UDP send failed: %s\n", strerror(errno));
                return 1;
        }

        printf("%zd bytes sent to remote server.\n", bytes);

        char buffer[MAX_LENGTH];
        bytes = read(sockfd, buffer, MAX_LENGTH);
        if (bytes > 0) {
                printf("Received %zd bytes from remote host\n", bytes);
                printf("%s\n", buffer);
        } else {
                // We are expecting this
                printf("Error: %s\n", strerror(errno));
        }
        close(sockfd);
        printf("Socket closed.\n");

        return 0;
}