/*
 / _____)             _              | |
( (____  _____ ____ _| |_ _____  ____| |__
 \____ \| ___ |    (_   _) ___ |/ ___)  _ \
 _____) ) ____| | | || |_| ____( (___| | | |
(______/|_____)_|_|_| \__)_____)\____)_| |_|
  (C)2013 Semtech-Cycleo

Description:
    Network sink, receives UDP packets on certain ports and discards them

License: Revised BSD License, see LICENSE.TXT file include in the project
Maintainer: Sylvain Miermont
*/


/* -------------------------------------------------------------------------- */
/* --- DEPENDANCIES --------------------------------------------------------- */

/* fix an issue between POSIX and C99 */
#if __STDC_VERSION__ >= 199901L
    #define _XOPEN_SOURCE 600
#else
    #define _XOPEN_SOURCE 500
#endif

#include <stdint.h>     /* C99 types */
#include <stdio.h>      /* printf, fprintf, sprintf, fopen, fputs */

#include <string.h>     /* memset */
#include <time.h>       /* time, clock_gettime, strftime, gmtime, clock_nanosleep*/
#include <stdlib.h>     /* atoi, exit */
#include <errno.h>      /* error messages */

#include <sys/socket.h> /* socket specific definitions */
#include <netinet/in.h> /* INET constants and stuff */
#include <arpa/inet.h>  /* IP address conversion stuff */
#include <netdb.h>      /* gai_strerror */

/* -------------------------------------------------------------------------- */
/* --- PRIVATE MACROS ------------------------------------------------------- */

#define ARRAY_SIZE(a)   (sizeof(a) / sizeof((a)[0]))
#define STRINGIFY(x)    #x
#define STR(x)          STRINGIFY(x)
#define MSG(args...)    fprintf(stderr, args) /* message that is destined to the user */

/* -------------------------------------------------------------------------- */
/* --- MAIN FUNCTION -------------------------------------------------------- */

int main(int argc, char **argv)
{
    int i; /* loop variable and temporary variable for return value */

    /* server socket creation */
    int sock; /* socket file descriptor */
    struct addrinfo hints;
    struct addrinfo *result; /* store result of getaddrinfo */
    struct addrinfo *q; /* pointer to move into *result data */
    char host_name[64];
    char port_name[64];

    /* variables for receiving packets */
    struct sockaddr_storage dist_addr;
    socklen_t addr_len = sizeof dist_addr;
    uint8_t databuf[4096];
    int byte_nb;

    /* check if port number was passed as parameter */
    if (argc != 2) {
        MSG("Usage: util_sink <port number>\n");
        exit(EXIT_FAILURE);
    }

    /* prepare hints to open network sockets */
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC; /* should handle IP v4 or v6 automatically */
    hints.ai_socktype = SOCK_DGRAM;
    hints.ai_flags = AI_PASSIVE; /* will assign local IP automatically */

    /* look for address */
    i = getaddrinfo(NULL, argv[1], &hints, &result);
    if (i != 0) {
        MSG("ERROR: getaddrinfo returned %s\n", gai_strerror(i));
        exit(EXIT_FAILURE);
    }

    /* try to open socket and bind it */
    for (q=result; q!=NULL; q=q->ai_next) {
        sock = socket(q->ai_family, q->ai_socktype,q->ai_protocol);
        if (sock == -1) {
            continue; /* socket failed, try next field */
        } else {
            i = bind(sock, q->ai_addr, q->ai_addrlen);
            if (i == -1) {
                shutdown(sock, SHUT_RDWR);
                continue; /* bind failed, try next field */
            } else {
                break; /* success, get out of loop */
            }
        }
    }
    if (q == NULL) {
        MSG("ERROR: failed to open socket or to bind to it\n");
        i = 1;
        for (q=result; q!=NULL; q=q->ai_next) {
            getnameinfo(q->ai_addr, q->ai_addrlen, host_name, sizeof host_name, port_name, sizeof port_name, NI_NUMERICHOST);
            MSG("result %i host:%s service:%s\n", i, host_name, port_name);
            ++i;
        }
        exit(EXIT_FAILURE);
    }
    MSG("INFO: util_sink listening on port %s\n", argv[1]);
    freeaddrinfo(result);

    while (1) {
        byte_nb = recvfrom(sock, databuf, sizeof databuf, 0, (struct sockaddr *)&dist_addr, &addr_len);
        if (byte_nb == -1) {
            MSG("ERROR: recvfrom returned %s \n", strerror(errno));
            exit(EXIT_FAILURE);
        }
        getnameinfo((struct sockaddr *)&dist_addr, addr_len, host_name, sizeof host_name, port_name, sizeof port_name, NI_NUMERICHOST);
        printf("Got packet from host %s port %s, %i bytes long\n", host_name, port_name, byte_nb);
    }
}