mirror of https://github.com/dirtbags/moth.git
72 lines
2.6 KiB
C
72 lines
2.6 KiB
C
/* multicast_server.c
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* Adapted from tmouse's IPv6 client/server example code
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* found at http://cboard.cprogramming.com/showthread.php?t=67469
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*/
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#include <stdio.h> /* for fprintf() */
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <stdlib.h> /* for atoi() and exit() */
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#include <unistd.h>
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#include <string.h>
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static void DieWithError(const char* errorMessage)
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{
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fprintf(stderr, "%s\n", errorMessage);
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exit(10);
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}
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int main(int argc, char *argv[])
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{
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int sock; /* Socket */
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char* multicastIP; /* Arg: IP Multicast address */
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char* multicastPort; /* Arg: Server port */
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char* sendString; /* Arg: String to multicast */
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size_t sendStringLen; /* Length of string to multicast */
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struct addrinfo * multicastAddr; /* Multicast address */
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struct addrinfo hints = { 0 }; /* Hints for name lookup */
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if ( argc != 4 )
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{
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fprintf(stderr, "Usage: %s <Multicast Address> <Port> <Send String>\n", argv[0]);
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exit(10);
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}
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multicastIP = argv[1]; /* First arg: multicast IP address */
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multicastPort = argv[2]; /* Second arg: multicast port */
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sendString = argv[3]; /* Third arg: String to multicast */
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sendStringLen = strlen(sendString); /* Find length of sendString */
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/* Resolve destination address for multicast datagrams */
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hints.ai_family = PF_INET6;
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hints.ai_socktype = SOCK_DGRAM;
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hints.ai_flags = AI_NUMERICHOST;
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if (getaddrinfo(multicastIP, multicastPort, &hints, &multicastAddr) != 0) DieWithError("getaddrinfo() failed");
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/* Create socket for sending multicast datagrams */
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if ((sock = socket(multicastAddr->ai_family, multicastAddr->ai_socktype, 0)) == -1) DieWithError("socket() failed");
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int hops = 5;
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if (setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &hops, sizeof(hops)) != 0) DieWithError("setsockopt(MULTICAST_HOPS) failed");
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for (;;) /* Run forever */
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{
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int sendLen = sendto(sock, sendString, sendStringLen, 0, multicastAddr->ai_addr, multicastAddr->ai_addrlen);
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if (sendLen == sendStringLen )
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{
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printf("Sent [%s] (%i bytes) to %s, port %s\n", sendString, sendLen, multicastIP, multicastPort);
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}
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else
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{
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DieWithError("sendto() sent a different number of bytes than expected");
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}
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sleep(1); /* Multicast sendString in datagram to clients every second */
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}
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/* NOT REACHED */
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freeaddrinfo(multicastAddr);
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close(sock);
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return 0;
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}
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