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/*
/ _____) _ | |
( (____ _____ ____ _| |_ _____ ____| |__
\____ \| ___ | (_ _) ___ |/ ___) _ \
_____) ) ____| | | || |_| ____( (___| | | |
(______/|_____)_|_|_| \__)_____)\____)_| |_|
(C)2013 Semtech-Cycleo
Description:
Network sink, receives UDP packets and sends an acknowledge
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 <unistd.h> /* usleep */
#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 */
/* -------------------------------------------------------------------------- */
/* --- PRIVATE CONSTANTS ---------------------------------------------------- */
#define PROTOCOL_VERSION 2
#define PKT_PUSH_DATA 0
#define PKT_PUSH_ACK 1
#define PKT_PULL_DATA 2
#define PKT_PULL_RESP 3
#define PKT_PULL_ACK 4
/* -------------------------------------------------------------------------- */
/* --- 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 and sending packets */
struct sockaddr_storage dist_addr;
socklen_t addr_len = sizeof dist_addr;
uint8_t databuf[4096];
int byte_nb;
/* variables for protocol management */
uint32_t raw_mac_h; /* Most Significant Nibble, network order */
uint32_t raw_mac_l; /* Least Significant Nibble, network order */
uint64_t gw_mac; /* MAC address of the client (gateway) */
uint8_t ack_command;
/* check if port number was passed as parameter */
if (argc != 2) {
MSG("Usage: util_ack <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("INFO: result %i host:%s service:%s\n", i, host_name, port_name);
++i;
}
exit(EXIT_FAILURE);
}
MSG("INFO: util_ack listening on port %s\n", argv[1]);
freeaddrinfo(result);
while (1) {
/* wait to receive a packet */
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);
}
/* display info about the sender */
i = getnameinfo((struct sockaddr *)&dist_addr, addr_len, host_name, sizeof host_name, port_name, sizeof port_name, NI_NUMERICHOST);
if (i == -1) {
MSG("ERROR: getnameinfo returned %s \n", gai_strerror(i));
exit(EXIT_FAILURE);
}
printf(" -> pkt in , host %s (port %s), %i bytes", host_name, port_name, byte_nb);
/* check and parse the payload */
if (byte_nb < 12) { /* not enough bytes for packet from gateway */
printf(" (too short for GW <-> MAC protocol)\n");
continue;
}
/* don't touch the token in position 1-2, it will be sent back "as is" for acknowledgement */
if (databuf[0] != PROTOCOL_VERSION) { /* check protocol version number */
printf(", invalid version %u\n", databuf[0]);
continue;
}
raw_mac_h = *((uint32_t *)(databuf+4));
raw_mac_l = *((uint32_t *)(databuf+8));
gw_mac = ((uint64_t)ntohl(raw_mac_h) << 32) + (uint64_t)ntohl(raw_mac_l);
/* interpret gateway command */
switch (databuf[3]) {
case PKT_PUSH_DATA:
printf(", PUSH_DATA from gateway 0x%08X%08X\n", (uint32_t)(gw_mac >> 32), (uint32_t)(gw_mac & 0xFFFFFFFF));
ack_command = PKT_PUSH_ACK;
printf("<- pkt out, PUSH_ACK for host %s (port %s)", host_name, port_name);
break;
case PKT_PULL_DATA:
printf(", PULL_DATA from gateway 0x%08X%08X\n", (uint32_t)(gw_mac >> 32), (uint32_t)(gw_mac & 0xFFFFFFFF));
ack_command = PKT_PULL_ACK;
printf("<- pkt out, PULL_ACK for host %s (port %s)", host_name, port_name);
break;
default:
printf(", unexpected command %u\n", databuf[3]);
continue;
}
/* add some artificial latency */
usleep(30000); /* 30 ms */
/* send acknowledge and check return value */
databuf[3] = ack_command;
byte_nb = sendto(sock, (void *)databuf, 4, 0, (struct sockaddr *)&dist_addr, addr_len);
if (byte_nb == -1) {
printf(", send error:%s\n", strerror(errno));
} else {
printf(", %i bytes sent\n", byte_nb);
}
}
}
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