network plugin: Added Interface option

Hello list!

Again I'm providing an interface option for the network plugin for
the manual selection of an incoming or outgoing interface,
incorporating the changes proposed by Florian and Sebastian.

Please look through it and feedback or suggest new changes! :-)

Best regards,

Max

Signed-off-by: Florian Forster <octo@huhu.verplant.org>

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 9cab554..c490a2e 100644 (file)
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -2569,6 +2569,13 @@ multicast, and IPv4 and IPv6 packets. The default is to not change this value.
 That means that multicast packets will be sent with a TTL of C<1> (one) on most
 operating systems.
 
+=item B<Interface> I<Interface name>
+
+Set the outgoing or incoming interface for multicast packets. This applies
+at least to IPv6 packets and if possible to IPv4. If it is not applicable or
+defined the default behaviour is to let the kernel choose the appropriate
+interface.
+
 =item B<MaxPacketSize> I<1024-65535>
 
 Set the maximum size for datagrams received over the network. Packets larger

diff --git a/src/network.c b/src/network.c
index 8615753..b6e21b9 100644 (file)
--- a/src/network.c
+++ b/src/network.c
@@ -52,6 +52,9 @@
 #if HAVE_POLL_H
 # include <poll.h>
 #endif
+#if HAVE_NET_IF_H
+# include <net/if.h>
+#endif
 
 #if HAVE_LIBGCRYPT
 # include <gcrypt.h>
@@ -254,6 +257,7 @@ typedef struct receive_list_entry_s receive_list_entry_t;
  * Private variables
  */
 static int network_config_ttl = 0;
+static int network_config_interface_idx = 0;
 static size_t network_config_packet_size = 1024;
 static int network_config_forward = 0;
 static int network_config_stats = 0;
@@ -1583,6 +1587,64 @@ static int network_set_ttl (const sockent_t *se, const struct addrinfo *ai)
        return (0);
 } /* int network_set_ttl */
 
+static int network_set_interface (const sockent_t *se, const struct addrinfo *ai) /* {{{ */
+{
+       DEBUG ("network plugin: network_set_interface: interface index = %i;",
+                       network_config_interface_idx);
+
+        assert (se->type == SOCKENT_TYPE_CLIENT);
+
+       if (ai->ai_family == AF_INET)
+       {
+               struct sockaddr_in *addr = (struct sockaddr_in *) ai->ai_addr;
+#if KERNEL_LINUX
+               struct ip_mreqn mreq;
+#else
+               struct ip_mreq mreq;
+#endif
+
+               if (! IN_MULTICAST (ntohl (addr->sin_addr.s_addr)))
+                       return (0);
+
+               mreq.imr_multiaddr.s_addr = addr->sin_addr.s_addr;
+#if KERNEL_LINUX
+               mreq.imr_address.s_addr = ntohl (INADDR_ANY);
+               mreq.imr_ifindex = network_config_interface_idx;
+#else
+               mreq.imr_interface.s_addr = ntohl (INADDR_ANY);
+#endif
+
+               if (setsockopt (se->data.client.fd, IPPROTO_IP, IP_MULTICAST_IF,
+                                       &mreq, sizeof (mreq)) == -1)
+               {
+                       char errbuf[1024];
+                       ERROR ("setsockopt: %s",
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
+                       return (-1);
+               }
+       }
+       else if (ai->ai_family == AF_INET6)
+       {
+               struct sockaddr_in6 *addr = (struct sockaddr_in6 *) ai->ai_addr;
+
+               if (! IN6_IS_ADDR_MULTICAST (&addr->sin6_addr))
+                       return (0);
+
+               if (setsockopt (se->data.client.fd, IPPROTO_IPV6, IPV6_MULTICAST_IF,
+                                       &network_config_interface_idx,
+                                       sizeof (network_config_interface_idx)) == -1)
+               {
+                       char errbuf[1024];
+                       ERROR ("setsockopt: %s",
+                                       sstrerror (errno, errbuf,
+                                               sizeof (errbuf)));
+                       return (-1);
+               }
+       }
+
+       return (0);
+} /* }}} network_set_interface */
+
 static int network_bind_socket (int fd, const struct addrinfo *ai)
 {
        int loop = 0;
@@ -1612,12 +1674,21 @@ static int network_bind_socket (int fd, const struct addrinfo *ai)
                struct sockaddr_in *addr = (struct sockaddr_in *) ai->ai_addr;
                if (IN_MULTICAST (ntohl (addr->sin_addr.s_addr)))
                {
+#if KERNEL_LINUX
+                       struct ip_mreqn mreq;
+#else
                        struct ip_mreq mreq;
+#endif
 
                        DEBUG ("fd = %i; IPv4 multicast address found", fd);
 
                        mreq.imr_multiaddr.s_addr = addr->sin_addr.s_addr;
-                       mreq.imr_interface.s_addr = htonl (INADDR_ANY);
+#if KERNEL_LINUX
+                       mreq.imr_address.s_addr = ntohl (INADDR_ANY);
+                       mreq.imr_ifindex = network_config_interface_idx;
+#else
+                       mreq.imr_interface.s_addr = ntohl (INADDR_ANY);
+#endif
 
                        if (setsockopt (fd, IPPROTO_IP, IP_MULTICAST_LOOP,
                                                &loop, sizeof (loop)) == -1)
@@ -1663,7 +1734,7 @@ static int network_bind_socket (int fd, const struct addrinfo *ai)
                         * single interface; programs running on
                         * multihomed hosts may need to join the same
                         * group on more than one interface.*/
-                       mreq.ipv6mr_interface = 0;
+                       mreq.ipv6mr_interface = network_config_interface_idx;
 
                        if (setsockopt (fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
                                                &loop, sizeof (loop)) == -1)
@@ -1890,6 +1961,7 @@ static int sockent_open (sockent_t *se) /* {{{ */
                        se->data.client.addrlen = ai_ptr->ai_addrlen;
 
                        network_set_ttl (se, ai_ptr);
+                       network_set_interface (se, ai_ptr);
 
                        /* We don't open more than one write-socket per
                         * node/service pair.. */
@@ -2601,6 +2673,21 @@ static int network_config_set_ttl (const oconfig_item_t *ci) /* {{{ */
   return (0);
 } /* }}} int network_config_set_ttl */
 
+static int network_config_set_interface (const oconfig_item_t *ci) /* {{{ */
+{
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("network plugin: The `Interface' config option needs exactly "
+        "one string argument.");
+    return (-1);
+  }
+
+  network_config_interface_idx = if_nametoindex (ci->values[0].value.string);
+
+  return (0);
+} /* }}} int network_config_set_interface */
+
 static int network_config_set_buffer_size (const oconfig_item_t *ci) /* {{{ */
 {
   int tmp;
@@ -2842,6 +2929,8 @@ static int network_config (oconfig_item_t *ci) /* {{{ */
       network_config_add_server (child);
     else if (strcasecmp ("TimeToLive", child->key) == 0)
       network_config_set_ttl (child);
+    else if (strcasecmp ("Interface", child->key) == 0)
+      network_config_set_interface (child);
     else if (strcasecmp ("MaxPacketSize", child->key) == 0)
       network_config_set_buffer_size (child);
     else if (strcasecmp ("Forward", child->key) == 0)