alias.c

   1 /*
   2  * netifd - network interface daemon
   3  * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14 #include <string.h>
  15 #include <stdlib.h>
  16 #include <stdio.h>
  17
  18 #include "netifd.h"
  19 #include "device.h"
  20 #include "interface.h"
  21
  22 static struct avl_tree aliases;
  23
  24 struct alias_device {
  25         struct avl_node avl;
  26         struct device dev;
  27         struct device_user dep;
  28         struct device_user new_dep;
  29         bool update;
  30         char name[];
  31 };
  32
  33 static const struct device_type alias_device_type;
  34
  35 static void alias_set_device(struct alias_device *alias, struct device *dev)
  36 {
  37         if (dev == alias->dep.dev)
  38                 return;
  39
  40         device_set_present(&alias->dev, false);
  41         device_remove_user(&alias->new_dep);
  42         if (alias->dev.active) {
  43                 if (dev)
  44                         device_add_user(&alias->new_dep, dev);
  45
  46                 alias->update = true;
  47                 return;
  48         }
  49
  50         alias->update = false;
  51         device_remove_user(&alias->dep);
  52         alias->dev.hidden = !dev;
  53         if (dev) {
  54                 strcpy(alias->dev.ifname, dev->ifname);
  55                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
  56                 device_add_user(&alias->dep, dev);
  57         } else {
  58                 alias->dev.ifname[0] = 0;
  59                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
  60         }
  61 }
  62
  63 static int
  64 alias_device_set_state(struct device *dev, bool state)
  65 {
  66         struct alias_device *alias;
  67
  68         alias = container_of(dev, struct alias_device, dev);
  69         if (!alias->dep.dev)
  70                 return -1;
  71
  72         if (state)
  73                 return device_claim(&alias->dep);
  74
  75         device_release(&alias->dep);
  76         if (alias->update)
  77                 alias_set_device(alias, alias->new_dep.dev);
  78
  79         return 0;
  80 }
  81
  82 static void alias_device_cb(struct device_user *dep, enum device_event ev)
  83 {
  84         struct alias_device *alias;
  85         bool present = false;
  86
  87         alias = container_of(dep, struct alias_device, dep);
  88         switch (ev) {
  89         case DEV_EVENT_ADD:
  90                 present = true;
  91         case DEV_EVENT_REMOVE:
  92                 device_set_present(&alias->dev, present);
  93                 break;
  94         default:
  95                 device_broadcast_event(&alias->dev, ev);
  96                 break;
  97         }
  98 }
  99
 100 static struct device *
 101 alias_device_create(const char *name, struct blob_attr *attr)
 102 {
 103         struct alias_device *alias;
 104
 105         alias = calloc(1, sizeof(*alias) + strlen(name) + 1);
 106         strcpy(alias->name, name);
 107         alias->dev.set_state = alias_device_set_state;
 108         alias->dev.hidden = true;
 109         device_init_virtual(&alias->dev, &alias_device_type, NULL);
 110         alias->avl.key = alias->name;
 111         avl_insert(&aliases, &alias->avl);
 112         alias->dep.alias = true;
 113         alias->dep.cb = alias_device_cb;
 114         device_check_state(&alias->dev);
 115
 116         return &alias->dev;
 117 }
 118
 119 static void alias_device_free(struct device *dev)
 120 {
 121         struct alias_device *alias;
 122
 123         alias = container_of(dev, struct alias_device, dev);
 124         avl_delete(&aliases, &alias->avl);
 125         free(alias);
 126 }
 127
 128 static int alias_check_state(struct device *dev)
 129 {
 130         struct alias_device *alias;
 131         struct interface *iface;
 132         struct device *ndev = NULL;
 133
 134         alias = container_of(dev, struct alias_device, dev);
 135
 136         iface = vlist_find(&interfaces, alias->name, iface, node);
 137         if (iface && iface->state == IFS_UP)
 138                 ndev = iface->l3_dev.dev;
 139
 140         alias_set_device(alias, ndev);
 141
 142         return 0;
 143 }
 144
 145 static const struct device_type alias_device_type = {
 146         .name = "Network alias",
 147         .create = alias_device_create,
 148         .free = alias_device_free,
 149         .check_state = alias_check_state,
 150 };
 151
 152 void
 153 alias_notify_device(const char *name, struct device *dev)
 154 {
 155         struct alias_device *alias;
 156
 157         device_lock();
 158
 159         alias = avl_find_element(&aliases, name, alias, avl);
 160         if (alias)
 161                 alias_set_device(alias, dev);
 162
 163         device_unlock();
 164 }
 165
 166 struct device *
 167 device_alias_get(const char *name)
 168 {
 169         struct alias_device *alias;
 170
 171         alias = avl_find_element(&aliases, name, alias, avl);
 172         if (alias)
 173                 return &alias->dev;
 174
 175         return alias_device_create(name, NULL);
 176 }
 177
 178 static void __init alias_init(void)
 179 {
 180         avl_init(&aliases, avl_strcmp, false, NULL);
 181 }