Premier essais avec une librairie json en c

git-svn-id: https://redmine.imt-atlantique.fr/svn/xaal/xAAL_C/trunk@426 b32b6428-25c9-4566-ad07-03861ab6144f

dumper/Makefile

+CFLAGS=-Wall
+LDFLAGS=-ljansson
+
+all:dumper
+
+test: dumper
+	./dumper 224.0.10.10 1234
+
+test6: dumper
+	./dumper ff15::0a0a 1234
+
+.PHONY: all test test6

dumper/dumper.c

+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+
+#include <jansson.h>
+
+#define BUF_SIZE 65536
+
+
+int main(int argc, char **argv) {
+  int s, sfd;
+  int one = 1;
+  struct sockaddr_storage peer_addr;
+  socklen_t peer_addr_len;
+  ssize_t nread;
+  char buf[BUF_SIZE];
+  struct ip_mreqn mreqn;
+  struct ipv6_mreq mreq6;
+  struct addrinfo hints;
+  struct addrinfo *result, *rp;
+  json_t *jroot;
+  json_error_t jerror;
+  
+
+  if (argc != 3) {
+    printf("Usage : %s multicast_addr port\n", argv[0]);
+    exit(EXIT_FAILURE);
+  }
+
+  memset(&hints, 0, sizeof(struct addrinfo));
+  hints.ai_family = AF_UNSPEC;		/* Allow IPv4 or IPv6 */
+  hints.ai_socktype = SOCK_DGRAM;	/* Datagram socket */
+  //hints.ai_flags = AI_PASSIVE;	/* For wildcard IP address */
+  hints.ai_protocol = 0;		/* Any protocol */
+  hints.ai_canonname = NULL;
+  hints.ai_addr = NULL;
+  hints.ai_next = NULL;
+
+  s = getaddrinfo(argv[1], argv[2], &hints, &result);
+  if (s != 0) {
+    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
+    exit(EXIT_FAILURE);
+  }
+
+  /* getaddrinfo() returns a list of address structures.
+     Try each address until we successfully bind(2).
+     If socket(2) (or bind(2)) fails, we (close the socket
+     and) try the next address. */ /*copy-paste from the man page*/
+  for (rp = result; rp != NULL; rp = rp->ai_next) {
+    sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+    if (sfd == -1)
+      continue;
+    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) == -1) {
+      perror("SO_REUSEADDR");
+      close(sfd);
+      continue;
+    }
+    if (bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0)
+      break;				/* Success */
+    perror(argv[2]);
+    close(sfd);
+  }
+  if (rp == NULL) {			/* No address succeeded */
+    fprintf(stderr, "Could not bind\n");
+    exit(EXIT_FAILURE);
+  }
+
+  /* Now, join the group */
+  switch (rp->ai_family) {
+    case AF_INET:
+      memcpy(&mreqn.imr_multiaddr.s_addr, &(((struct sockaddr_in*)(rp->ai_addr))->sin_addr), sizeof(struct in_addr));
+      mreqn.imr_address.s_addr = INADDR_ANY;
+      mreqn.imr_ifindex = 0;
+      s = setsockopt(sfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreqn, sizeof(mreqn));
+      break;
+    case AF_INET6:
+      memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6*)(rp->ai_addr))->sin6_addr), sizeof(struct in6_addr));
+      mreq6.ipv6mr_interface = 0;
+      s = setsockopt(sfd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6));
+      break;
+    default:
+      s = -1;
+  }
+  if (s != 0)				/* Success */
+    perror("Could not join the multicast group");
+
+  freeaddrinfo(result);			/* No longer needed */
+
+
+  /************************************/
+
+  for (;;) {
+    /* Recive a message */
+    peer_addr_len = sizeof(struct sockaddr_storage);
+    nread = recvfrom(sfd, buf, BUF_SIZE, 0,
+            (struct sockaddr *)&peer_addr, &peer_addr_len);
+    if (nread == -1)
+      continue;				/* Ignore failed request */
+
+    /* Name of the sender */
+    char host[NI_MAXHOST], service[NI_MAXSERV];
+    s = getnameinfo((struct sockaddr *) &peer_addr,
+                    peer_addr_len, host, NI_MAXHOST,
+                    service, NI_MAXSERV, NI_NUMERICSERV);
+    if (s == 0)
+      printf("Received %zd bytes from %s:%s\n", nread, host, service);
+    else
+      fprintf(stderr, "getnameinfo: %s\n", gai_strerror(s));
+      
+    /* Use the Jansson library */
+    jroot = json_loadb(buf, nread, 0, &jerror);
+    if ( jroot == NULL ) {
+      fprintf(stderr, "JSON error on line %d: %s\n", jerror.line, jerror.text);
+      write(STDOUT_FILENO, buf, nread);
+    }
+    else {
+      json_dumpf(jroot, stdout, JSON_INDENT(2));
+      json_decref(jroot);
+    }
+    printf("\n");
+  }
+}

dumper/dumper.sh

+# ADDR="[ff15::0a0a]"
+ADDR="224.0.10.10"
+PORT="1234"
+TTL="2"
+
+socat UDP-DATAGRAM:$ADDR:$PORT,bind=:$PORT,ip-add-membership=$ADDR:0,reuseaddr STDIO \
+	| while read LINE ; do
+		jshon -Q -C <<< "$LINE" || echo "$LINE"
+	done
+
+# Does socat realy support IPv6 multicast?