src/libcharon/plugins/dhcp/dhcp_plugin.c

   1 /*
   2  * Copyright (C) 2013 Tobias Brunner
   3  * HSR Hochschule fuer Technik Rapperswil
   4  *
   5  * Copyright (C) 2010 Martin Willi
   6  * Copyright (C) 2010 revosec AG
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2 of the License, or (at your
  11  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  */
  18
  19 #include "dhcp_plugin.h"
  20
  21 #include <daemon.h>
  22 #include <plugins/plugin_feature.h>
  23
  24 #include "dhcp_socket.h"
  25 #include "dhcp_provider.h"
  26
  27 typedef struct private_dhcp_plugin_t private_dhcp_plugin_t;
  28
  29 /**
  30  * private data of dhcp plugin
  31  */
  32 struct private_dhcp_plugin_t {
  33
  34         /**
  35          * implements plugin interface
  36          */
  37         dhcp_plugin_t public;
  38
  39         /**
  40          * DHCP communication socket
  41          */
  42         dhcp_socket_t *socket;
  43
  44         /**
  45          * Attribute provider
  46          */
  47         dhcp_provider_t *provider;
  48 };
  49
  50 METHOD(plugin_t, get_name, char*,
  51         private_dhcp_plugin_t *this)
  52 {
  53         return "dhcp";
  54 }
  55
  56 /**
  57  * Register listener
  58  */
  59 static bool plugin_cb(private_dhcp_plugin_t *this,
  60                                           plugin_feature_t *feature, bool reg, void *cb_data)
  61 {
  62         if (reg)
  63         {
  64                 this->socket = dhcp_socket_create();
  65
  66                 if (!this->socket)
  67                 {
  68                         return FALSE;
  69                 }
  70                 this->provider = dhcp_provider_create(this->socket);
  71                 charon->attributes->add_provider(charon->attributes,
  72                                                                                  &this->provider->provider);
  73         }
  74         else
  75         {
  76                 charon->attributes->remove_provider(charon->attributes,
  77                                                                                         &this->provider->provider);
  78                 this->provider->destroy(this->provider);
  79                 this->socket->destroy(this->socket);
  80         }
  81         return TRUE;
  82 }
  83
  84 METHOD(plugin_t, get_features, int,
  85         private_dhcp_plugin_t *this, plugin_feature_t *features[])
  86 {
  87         static plugin_feature_t f[] = {
  88                 PLUGIN_CALLBACK((plugin_feature_callback_t)plugin_cb, NULL),
  89                         PLUGIN_PROVIDE(CUSTOM, "dhcp"),
  90                                 PLUGIN_DEPENDS(RNG, RNG_WEAK),
  91         };
  92         *features = f;
  93         return countof(f);
  94 }
  95
  96 METHOD(plugin_t, destroy, void,
  97         private_dhcp_plugin_t *this)
  98 {
  99         free(this);
 100 }
 101
 102 /**
 103  * Plugin constructor.
 104  */
 105 plugin_t *dhcp_plugin_create()
 106 {
 107         private_dhcp_plugin_t *this;
 108
 109         if (!lib->caps->check(lib->caps, CAP_NET_BIND_SERVICE))
 110         {       /* required to bind DHCP socket (port 68) */
 111                 DBG1(DBG_NET, "dhcp plugin requires CAP_NET_BIND_SERVICE capability");
 112                 return NULL;
 113         }
 114         else if (!lib->caps->keep(lib->caps, CAP_NET_RAW))
 115         {       /* required to open DHCP receive socket (AF_PACKET). according to
 116                  * capabilities(7) it is also required to use the socket */
 117                 DBG1(DBG_NET, "dhcp plugin requires CAP_NET_RAW capability");
 118                 return NULL;
 119         }
 120
 121         INIT(this,
 122                 .public = {
 123                         .plugin = {
 124                                 .get_name = _get_name,
 125                                 .get_features = _get_features,
 126                                 .destroy = _destroy,
 127                         },
 128                 },
 129         );
 130
 131         return &this->public.plugin;
 132 }