gluon-announced: send nodeinformation on request

This is a simple daemon that will respond to multicast UDP packets
containing the keyword "nodeinfo" with all the information we
currently distribute using alfred.

The daemon will listen on all mesh interface, that is the hard
interfaces batman-adv uses.

package/gluon-announced/Makefile

@@ -0,0 +1,40 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=gluon-announced
+PKG_VERSION:=1
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/gluon-announced
+  SECTION:=gluon
+  CATEGORY:=Gluon
+  TITLE:=announced support
+  DEPENDS:=
+endef
+
+define Package/gluon-announced/description
+	Gluon community wifi mesh firmware framework: announced support
+endef
+
+define Build/Prepare
+	mkdir -p $(PKG_BUILD_DIR)
+	$(CP) ./src/* $(PKG_BUILD_DIR)/
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+	CFLAGS="$(TARGET_CFLAGS)" CPPFLAGS="$(TARGET_CPPFLAGS)" $(MAKE) -C $(PKG_BUILD_DIR) $(TARGET_CONFIGURE_OPTS)
+endef
+
+define Package/gluon-announced/install
+	$(CP) ./files/* $(1)/
+	$(INSTALL_DIR) $(1)/usr/bin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/gluon-announced $(1)/usr/bin/
+endef
+
+$(eval $(call BuildPackage,gluon-announced))

package/gluon-announced/files/etc/hotplug.d/iface/10-gluon-announced

@@ -0,0 +1,45 @@
+#!/bin/sh
+
+. /usr/share/libubox/jshn.sh
+. /lib/functions/service.sh
+
+DEVLIST=/var/run/gluon-announce.devs
+DAEMON=/usr/bin/gluon-announced
+
+ifname_to_dev () {
+	json_load "$(ubus call network.interface.$1 status)"
+	json_get_var dev device
+
+	echo "$dev"
+}
+
+restart_announced () {
+	SERVICE_USE_PID=1
+	SERVICE_WRITE_PID=1
+	SERVICE_DAEMONIZE=1
+
+	DEVS=$(cat $DEVLIST | while read dev iface;do echo -n " -i $dev";done)
+
+	service_stop $DAEMON
+	service_start $DAEMON -g ff02:0:0:0:0:0:2:1001 -p 1001 -s /lib/gluon/announce/announce.lua $DEVS
+}
+
+case "$ACTION" in
+	ifdown)
+		sed -i "/$INTERFACE/d" $DEVLIST
+		;;
+	ifup)
+		DEVICE=$(ifname_to_dev $INTERFACE)
+		MESH=$(cat /sys/class/net/$DEVICE/batman_adv/mesh_iface)
+
+		[ $MESH = "bat0" ] || exit 0
+
+		DEVS="$(cat $DEVLIST; echo $DEVICE $INTERFACE)"
+
+		echo "$DEVS" | sort | uniq > $DEVLIST
+
+		restart_announced
+
+		;;
+esac
+

package/gluon-announced/src/Makefile

@@ -0,0 +1,6 @@
+all: gluon-announced
+
+gluon-announced: gluon-announced.c
+
+clean:
+	rm gluon-announced

package/gluon-announced/src/gluon-announced.c

@@ -0,0 +1,229 @@
+/*
+   Copyright (c) 2014, Nils Schneider <nils@nilsschneider.net>
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+
+   1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+   */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+void usage() {
+  puts("Usage: gluon-announced [-h] -m <group> -p <port> -i <if0> [-i <if1> ..] -s <script>");
+  puts("  -m <ip6>         multicast group, e.g. ff02:0:0:0:0:0:2:1001");
+  puts("  -p <int>         port number to listen on");
+  puts("  -i <string>      interface on which the group is joined");
+  puts("  -s <string>      script to be executed for each request");
+  puts("  -h               this help\n");
+}
+
+/* The maximum size of output returned is limited to 8192 bytes (including
+ * terminating null byte) for now. If this turns out to be problem, a
+ * dynamic buffer should be implemented instead of increasing the
+ * limit.
+ */
+#define BUFFER 8192
+
+char *run_script(size_t *length, const char *script) {
+  FILE *f;
+
+  f = popen(script, "r");
+
+  char *buffer;
+
+  buffer = calloc(BUFFER, sizeof(char));
+
+  if (buffer == NULL) {
+    fprintf(stderr, "couldn't allocate buffer\n");
+    return NULL;
+  }
+
+
+  size_t read_bytes = 0;
+  while (1) {
+    ssize_t ret = fread(buffer+read_bytes, sizeof(char), BUFFER-read_bytes, f);
+
+    if (ret <= 0)
+      break;
+
+    read_bytes += ret;
+  }
+
+  if (fclose(f) != 0)
+    fprintf(stderr, "fclose on script failed\n");
+
+  *length = read_bytes;
+
+  return buffer;
+}
+
+void join_mcast(const int sock, const struct in6_addr addr, const char *iface) {
+  struct ipv6_mreq mreq;
+
+  mreq.ipv6mr_multiaddr = addr;
+  mreq.ipv6mr_interface = if_nametoindex(iface);
+
+  if (mreq.ipv6mr_interface == 0)
+    goto error;
+
+  if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) == -1)
+    goto error;
+
+  return;
+
+error:
+  fprintf(stderr, "Could not join multicast group on %s: ", iface);
+  perror(NULL);
+  return;
+}
+
+#define REQUESTSIZE 64
+
+char *recvrequest(const int sock, struct sockaddr *client_addr, socklen_t *clilen) {
+  char request_buffer[REQUESTSIZE];
+  ssize_t read_bytes;
+
+  read_bytes = recvfrom(sock, request_buffer, sizeof(request_buffer), 0, client_addr, clilen);
+
+  if (read_bytes < 0) {
+    perror("recvfrom failed");
+    exit(EXIT_FAILURE);
+  }
+
+  char *request = strndup(request_buffer, read_bytes);
+
+  if (request == NULL)
+    perror("Could not receive request");
+
+  return strsep(&request, "\r\n\t ");
+}
+
+void serve(const int sock, const char *script) {
+  char *request;
+  socklen_t clilen;
+  struct sockaddr_in6 client_addr;
+
+  clilen = sizeof(client_addr);
+
+  while (1) {
+    request = recvrequest(sock, (struct sockaddr*)&client_addr, &clilen);
+
+    int cmp = strcmp(request, "nodeinfo");
+    free(request);
+
+    if (cmp != 0)
+      continue;
+
+    char *msg;
+    size_t msg_length;
+    msg = run_script(&msg_length, script);
+
+    if (sendto(sock, msg, msg_length, 0, (struct sockaddr *)&client_addr, sizeof(client_addr)) < 0) {
+      perror("sendto failed");
+      exit(EXIT_FAILURE);
+    }
+
+    free(msg);
+  }
+}
+
+int main(int argc, char **argv) {
+  int sock;
+  struct sockaddr_in6 server_addr = {};
+  char *script = NULL;
+  struct in6_addr mgroup_addr;
+
+  sock = socket(PF_INET6, SOCK_DGRAM, 0);
+
+  if (sock < 0) {
+    perror("creating socket");
+    exit(EXIT_FAILURE);
+  }
+
+  server_addr.sin6_family = AF_INET6;
+  server_addr.sin6_addr = in6addr_any;
+
+  opterr = 0;
+
+  int group_set = 0;
+
+  int c;
+  while ((c = getopt(argc, argv, "p:g:s:i:h")) != -1)
+    switch (c) {
+      case 'p':
+        server_addr.sin6_port = htons(atoi(optarg));
+        break;
+      case 'g':
+        if (!inet_pton(AF_INET6, optarg, &mgroup_addr)) {
+          perror("Invalid multicast group. This message will probably confuse you");
+          exit(EXIT_FAILURE);
+        }
+
+        group_set = 1;
+        break;
+      case 's':
+        free(script); // in case -s is given multiple times
+
+        script = strdup(optarg);
+
+        if (script == NULL) {
+          perror("Couldn't duplicate string");
+          exit(EXIT_FAILURE);
+        }
+        break;
+      case 'i':
+        if (!group_set) {
+          fprintf(stderr, "Multicast group must be given before interface.\n");
+          exit(EXIT_FAILURE);
+        }
+        join_mcast(sock, mgroup_addr, optarg);
+        break;
+      case 'h':
+        usage();
+        exit(EXIT_SUCCESS);
+        break;
+      default:
+        fprintf(stderr, "Invalid parameter %c ignored.\n", c);
+    }
+
+  if (script == NULL) {
+    fprintf(stderr, "No script given\n");
+    exit(EXIT_FAILURE);
+  }
+
+  if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+    perror("bind failed");
+    exit(EXIT_FAILURE);
+  }
+
+  serve(sock, script);
+
+  free(script);
+
+  return EXIT_FAILURE;
+}