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_remove_user(&alias->new_dep);
  41         if (alias->dev.active) {
  42                 if (dev)
  43                         device_add_user(&alias->new_dep, dev);
  44
  45                 alias->update = true;
  46                 return;
  47         }
  48
  49         alias->update = false;
  50         device_remove_user(&alias->dep);
  51         alias->dev.hidden = !dev;
  52         if (dev) {
  53                 strcpy(alias->dev.ifname, dev->ifname);
  54                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
  55                 device_add_user(&alias->dep, dev);
  56         } else {
  57                 alias->dev.ifname[0] = 0;
  58                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
  59         }
  60 }
  61
  62 static int
  63 alias_device_set_state(struct device *dev, bool state)
  64 {
  65         struct alias_device *alias;
  66
  67         alias = container_of(dev, struct alias_device, dev);
  68         if (!alias->dep.dev)
  69                 return -1;
  70
  71         if (state)
  72                 return device_claim(&alias->dep);
  73
  74         device_release(&alias->dep);
  75         if (alias->update)
  76                 alias_set_device(alias, alias->new_dep.dev);
  77
  78         return 0;
  79 }
  80
  81 static void alias_device_cb(struct device_user *dep, enum device_event ev)
  82 {
  83         struct alias_device *alias;
  84         bool present = false;
  85
  86         alias = container_of(dep, struct alias_device, dep);
  87         switch (ev) {
  88         case DEV_EVENT_ADD:
  89                 present = true;
  90         case DEV_EVENT_REMOVE:
  91                 device_set_present(&alias->dev, present);
  92                 break;
  93         default:
  94                 device_broadcast_event(&alias->dev, ev);
  95                 break;
  96         }
  97 }
  98
  99 static struct device *
 100 alias_device_create(const char *name, struct blob_attr *attr)
 101 {
 102         struct alias_device *alias;
 103
 104         alias = calloc(1, sizeof(*alias) + strlen(name) + 1);
 105         strcpy(alias->name, name);
 106         alias->dev.set_state = alias_device_set_state;
 107         alias->dev.hidden = true;
 108         device_init_virtual(&alias->dev, &alias_device_type, NULL);
 109         alias->avl.key = alias->name;
 110         avl_insert(&aliases, &alias->avl);
 111         alias->dep.alias = true;
 112         alias->dep.cb = alias_device_cb;
 113         device_check_state(&alias->dev);
 114
 115         return &alias->dev;
 116 }
 117
 118 static void alias_device_free(struct device *dev)
 119 {
 120         struct alias_device *alias;
 121
 122         alias = container_of(dev, struct alias_device, dev);
 123         avl_delete(&aliases, &alias->avl);
 124         free(alias);
 125 }
 126
 127 static int alias_check_state(struct device *dev)
 128 {
 129         struct alias_device *alias;
 130         struct interface *iface;
 131         struct device *ndev = NULL;
 132
 133         alias = container_of(dev, struct alias_device, dev);
 134
 135         iface = vlist_find(&interfaces, alias->name, iface, node);
 136         if (iface && iface->state == IFS_UP)
 137                 ndev = iface->l3_dev.dev;
 138
 139         alias_set_device(alias, ndev);
 140
 141         return 0;
 142 }
 143
 144 static const struct device_type alias_device_type = {
 145         .name = "Network alias",
 146         .create = alias_device_create,
 147         .free = alias_device_free,
 148         .check_state = alias_check_state,
 149 };
 150
 151 void
 152 alias_notify_device(const char *name, struct device *dev)
 153 {
 154         struct alias_device *alias;
 155
 156         device_lock();
 157
 158         alias = avl_find_element(&aliases, name, alias, avl);
 159         if (alias)
 160                 alias_set_device(alias, dev);
 161
 162         device_unlock();
 163 }
 164
 165 struct device *
 166 device_alias_get(const char *name)
 167 {
 168         struct alias_device *alias;
 169
 170         alias = avl_find_element(&aliases, name, alias, avl);
 171         if (alias)
 172                 return &alias->dev;
 173
 174         return alias_device_create(name, NULL);
 175 }
 176
 177 static void __init alias_init(void)
 178 {
 179         avl_init(&aliases, avl_strcmp, false, NULL);
 180 }