mirror of https://github.com/dirtbags/moth.git
110 lines
3.9 KiB
C
110 lines
3.9 KiB
C
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/* multicast_client.c
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* Adopted from tmouse's 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 <sys/types.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <stdio.h> /* for printf() and fprintf() */
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#include <stdlib.h> /* for atoi() and exit() */
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#include <string.h> /* for memset() */
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#include <time.h> /* for timestamps */
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#include <unistd.h>
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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: Port */
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struct addrinfo * multicastAddr = {0}; /* Multicast Address */
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struct addrinfo * localAddr; /* Local address to bind to */
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struct addrinfo hints = { 0 }; /* Hints for name lookup */
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if ( argc != 3 )
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{
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fprintf(stderr,"Usage: %s <Multicast IP> <Multicast Port>\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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/* Resolve the multicast group address */
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hints.ai_family = PF_INET6;
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hints.ai_flags = AI_NUMERICHOST;
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if ( getaddrinfo(multicastIP, NULL, &hints, &multicastAddr) != 0 ) DieWithError("getaddrinfo() failed");
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/* Get a local address with the same family as our multicast group */
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hints.ai_family = multicastAddr->ai_family;
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hints.ai_socktype = SOCK_DGRAM;
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hints.ai_flags = AI_PASSIVE; /* Return an address we can bind to */
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if ( getaddrinfo(NULL, multicastPort, &hints, &localAddr) != 0 )
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{
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DieWithError("getaddrinfo() failed");
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}
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/* Create socket for receiving datagrams */
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if ( (sock = socket(localAddr->ai_family, localAddr->ai_socktype, 0)) == -1 )
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{
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DieWithError("socket() failed");
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}
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const int trueValue = 1;
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setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const void *) &trueValue, sizeof(trueValue));
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#ifdef __APPLE__
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setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const void *) &trueValue, sizeof(trueValue));
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#endif
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/* Bind to the multicast port */
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if ( bind(sock, localAddr->ai_addr, localAddr->ai_addrlen) != 0 )
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{
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DieWithError("bind() failed");
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}
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/* Join the multicast group. */
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if ((multicastAddr->ai_family == PF_INET6)&&(multicastAddr->ai_addrlen == sizeof(struct sockaddr_in6)))
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{
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struct sockaddr_in6 *addr = (struct sockaddr_in6 *)(multicastAddr->ai_addr);
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struct ipv6_mreq multicastRequest; /* Multicast address join structure */
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/* Specify the multicast group */
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memcpy(&multicastRequest.ipv6mr_multiaddr, &((struct sockaddr_in6*)(multicastAddr->ai_addr))->sin6_addr, sizeof(multicastRequest.ipv6mr_multiaddr));
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printf("scope_id: %d\n", addr->sin6_scope_id);
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/* Accept multicast from any interface */
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multicastRequest.ipv6mr_interface = addr->sin6_scope_id;
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/* Join the multicast address */
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if ( setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, (char*) &multicastRequest, sizeof(multicastRequest)) != 0 ) DieWithError("setsockopt(IPV6_JOIN_GROUP) failed");
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}
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else DieWithError("Not IPv6");
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freeaddrinfo(localAddr);
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freeaddrinfo(multicastAddr);
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for (;;) /* Run forever */
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{
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char recvString[500]; /* Buffer for received string */
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int recvStringLen; /* Length of received string */
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/* Receive a single datagram from the server */
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if ((recvStringLen = recvfrom(sock, recvString, sizeof(recvString) - 1, 0, NULL, 0)) < 0) DieWithError("recvfrom() failed");
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recvString[recvStringLen] = '\0';
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/* Print the received string */
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printf("Received string [%s]\n", recvString);
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}
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/* NOT REACHED */
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close(sock);
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exit(EXIT_SUCCESS);
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}
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