add multicaster

packages/multicaster/multicaster.mk

@@ -0,0 +1,16 @@
+MULTICASTER_PKGDIR = $(TARGET)/multicaster
+
+multicaster-install: multicaster-build
+	mkdir -p $(MULTICASTER_PKGDIR)
+
+	mkdir -p $(MULTICASTER_PKGDIR)/bin/
+	$(MAKE) -C packages/multicaster/src install DESTDIR=$(CURDIR)/$(MULTICASTER_PKGDIR)
+
+multicaster-clean:
+	rm -rf $(MULTICASTER_PKGDIR)
+	$(MAKE) -C packages/multicaster/src clean
+
+multicaster-build:
+	$(MAKE) -C packages/multicaster/src build
+
+PACKAGES += multicaster

packages/multicaster/src/Makefile

@@ -0,0 +1,12 @@
+CFLAGS = -Wall -Werror
+LDFLAGS = -static
+TARGETS = multicaster-server multicaster-client
+
+all: build
+build: $(TARGETS)
+
+install: $(TARGETS)
+	install -m 0755 $(TARGETS) $(DESTDIR)/bin
+
+clean:
+	rm -f *.o $(TARGETS)

packages/multicaster/src/multicaster-client.c

@@ -0,0 +1,109 @@
+/* multicast_client.c
+ * Adopted from tmouse's client/server example code
+ * found at http://cboard.cprogramming.com/showthread.php?t=67469
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>      /* for printf() and fprintf() */
+#include <stdlib.h>     /* for atoi() and exit() */
+#include <string.h>     /* for memset() */
+#include <time.h>       /* for timestamps */
+#include <unistd.h>
+
+void DieWithError(const char* errorMessage)
+{
+    fprintf(stderr, "%s\n", errorMessage);
+    exit(10);
+}
+
+int main(int argc, char* argv[])
+{
+    int     sock;                     /* Socket */
+    char*      multicastIP;              /* Arg: IP Multicast Address */
+    char*      multicastPort;            /* Arg: Port */
+    struct addrinfo *  multicastAddr = {0};            /* Multicast Address */
+    struct addrinfo *  localAddr;                /* Local address to bind to */
+    struct addrinfo    hints          = { 0 };   /* Hints for name lookup */
+
+    if ( argc != 3 )
+    {
+        fprintf(stderr,"Usage: %s <Multicast IP> <Multicast Port>\n", argv[0]);
+        exit(10);
+    }
+
+    multicastIP   = argv[1];      /* First arg:  Multicast IP address */
+    multicastPort = argv[2];      /* Second arg: Multicast port */
+
+    /* Resolve the multicast group address */
+    hints.ai_family = PF_INET6;
+    hints.ai_flags  = AI_NUMERICHOST;
+    if ( getaddrinfo(multicastIP, NULL, &hints, &multicastAddr) != 0 ) DieWithError("getaddrinfo() failed");
+
+    /* Get a local address with the same family as our multicast group */
+    hints.ai_family   = multicastAddr->ai_family;
+    hints.ai_socktype = SOCK_DGRAM;
+    hints.ai_flags    = AI_PASSIVE; /* Return an address we can bind to */
+    if ( getaddrinfo(NULL, multicastPort, &hints, &localAddr) != 0 )
+    {
+        DieWithError("getaddrinfo() failed");
+    }
+
+    /* Create socket for receiving datagrams */
+    if ( (sock = socket(localAddr->ai_family, localAddr->ai_socktype, 0)) == -1 )
+    {
+        DieWithError("socket() failed");
+    }
+
+    const int trueValue = 1;
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const void *) &trueValue, sizeof(trueValue));
+#ifdef __APPLE__
+    setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, (const void *) &trueValue, sizeof(trueValue));
+#endif
+
+    /* Bind to the multicast port */
+    if ( bind(sock, localAddr->ai_addr, localAddr->ai_addrlen) != 0 )
+    {
+        DieWithError("bind() failed");
+    }
+
+    /* Join the multicast group.  */
+    if ((multicastAddr->ai_family == PF_INET6)&&(multicastAddr->ai_addrlen == sizeof(struct sockaddr_in6)))
+    {
+      struct sockaddr_in6 *addr = (struct sockaddr_in6 *)(multicastAddr->ai_addr);
+      struct ipv6_mreq multicastRequest;  /* Multicast address join structure */
+
+      /* Specify the multicast group */
+      memcpy(&multicastRequest.ipv6mr_multiaddr, &((struct sockaddr_in6*)(multicastAddr->ai_addr))->sin6_addr, sizeof(multicastRequest.ipv6mr_multiaddr));
+
+      printf("scope_id: %d\n", addr->sin6_scope_id);
+
+      /* Accept multicast from any interface */
+      multicastRequest.ipv6mr_interface = addr->sin6_scope_id;
+
+      /* Join the multicast address */
+      if ( setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, (char*) &multicastRequest, sizeof(multicastRequest)) != 0 ) DieWithError("setsockopt(IPV6_JOIN_GROUP) failed");
+    }
+    else DieWithError("Not IPv6");
+
+    freeaddrinfo(localAddr);
+    freeaddrinfo(multicastAddr);
+
+    for (;;) /* Run forever */
+    {
+        char   recvString[500];      /* Buffer for received string */
+        int    recvStringLen;        /* Length of received string */
+
+        /* Receive a single datagram from the server */
+        if ((recvStringLen = recvfrom(sock, recvString, sizeof(recvString) - 1, 0, NULL, 0)) < 0) DieWithError("recvfrom() failed");
+        recvString[recvStringLen] = '\0';
+
+        /* Print the received string */
+        printf("Received string [%s]\n", recvString);
+    }
+
+    /* NOT REACHED */
+    close(sock);
+    exit(EXIT_SUCCESS);
+}

packages/multicaster/src/multicaster-server.c

@@ -0,0 +1,71 @@
+/* multicast_server.c
+ * Adapted from tmouse's IPv6 client/server example code
+ * found at http://cboard.cprogramming.com/showthread.php?t=67469
+ */
+
+#include <stdio.h>      /* for fprintf() */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdlib.h>     /* for atoi() and exit() */
+#include <unistd.h>
+#include <string.h>
+
+static void DieWithError(const char* errorMessage)
+{
+    fprintf(stderr, "%s\n", errorMessage);
+    exit(10);
+}
+
+int main(int argc, char *argv[])
+{
+    int    sock;                   /* Socket */
+    char*     multicastIP;            /* Arg: IP Multicast address */
+    char*     multicastPort;          /* Arg: Server port */
+    char*     sendString;             /* Arg: String to multicast */
+    size_t    sendStringLen;          /* Length of string to multicast */
+    struct addrinfo * multicastAddr;          /* Multicast address */
+    struct addrinfo   hints          = { 0 }; /* Hints for name lookup */
+
+    if ( argc != 4 )
+    {
+        fprintf(stderr, "Usage:  %s <Multicast Address> <Port> <Send String>\n", argv[0]);
+        exit(10);
+    }
+
+    multicastIP   = argv[1];             /* First arg:   multicast IP address */
+    multicastPort = argv[2];             /* Second arg:  multicast port */
+    sendString    = argv[3];             /* Third arg:   String to multicast */
+    sendStringLen = strlen(sendString);  /* Find length of sendString */
+
+    /* Resolve destination address for multicast datagrams */
+    hints.ai_family   = PF_INET6;
+    hints.ai_socktype = SOCK_DGRAM;
+    hints.ai_flags    = AI_NUMERICHOST;
+    if (getaddrinfo(multicastIP, multicastPort, &hints, &multicastAddr) != 0) DieWithError("getaddrinfo() failed");
+
+    /* Create socket for sending multicast datagrams */
+    if ((sock = socket(multicastAddr->ai_family, multicastAddr->ai_socktype, 0)) == -1) DieWithError("socket() failed");
+
+    //int scope_id = if_nametoindex("eth0");
+    //if (setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_IF, (const char *) &scope_id, sizeof(scope_id)) != 0) DieWithError("setsockopt(MULTICAST_IF) failed");
+
+    for (;;) /* Run forever */
+    {
+        int sendLen = sendto(sock, sendString, sendStringLen, 0, multicastAddr->ai_addr, multicastAddr->ai_addrlen);
+        if (sendLen == sendStringLen )
+        {
+            printf("Sent [%s] (%i bytes) to %s, port %s\n", sendString, sendLen, multicastIP, multicastPort);
+        }
+        else
+        {
+            DieWithError("sendto() sent a different number of bytes than expected");
+        }
+        sleep(1); /* Multicast sendString in datagram to clients every second */
+    }
+
+    /* NOT REACHED */
+    freeaddrinfo(multicastAddr);
+    close(sock);
+    return 0;
+}