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
  21 static struct avl_tree aliases;
  22
  23 struct alias_device {
  24         struct avl_node avl;
  25         struct device dev;
  26         struct device_user dep;
  27         bool cleanup;
  28         char name[];
  29 };
  30
  31 static const struct device_type alias_device_type;
  32
  33 static int
  34 alias_device_set_state(struct device *dev, bool state)
  35 {
  36         struct alias_device *alias;
  37
  38         alias = container_of(dev, struct alias_device, dev);
  39         if (!alias->dep.dev)
  40                 return -1;
  41
  42         if (state)
  43                 return device_claim(&alias->dep);
  44
  45         device_release(&alias->dep);
  46         if (alias->cleanup)
  47                 device_remove_user(&alias->dep);
  48         return 0;
  49 }
  50
  51 static void alias_device_cb(struct device_user *dep, enum device_event ev)
  52 {
  53         struct alias_device *alias;
  54         bool present = false;
  55
  56         alias = container_of(dep, struct alias_device, dep);
  57         switch (ev) {
  58         case DEV_EVENT_ADD:
  59                 present = true;
  60         case DEV_EVENT_REMOVE:
  61                 device_set_present(&alias->dev, present);
  62                 break;
  63         default:
  64                 device_broadcast_event(&alias->dev, ev);
  65                 break;
  66         }
  67 }
  68
  69 static struct device *
  70 alias_device_create(const char *name, struct blob_attr *attr)
  71 {
  72         struct alias_device *alias;
  73
  74         alias = calloc(1, sizeof(*alias) + strlen(name) + 1);
  75         strcpy(alias->name, name);
  76         alias->dev.set_state = alias_device_set_state;
  77         alias->dev.hidden = true;
  78         device_init_virtual(&alias->dev, &alias_device_type, NULL);
  79         alias->avl.key = alias->name;
  80         avl_insert(&aliases, &alias->avl);
  81         alias->dep.alias = true;
  82         alias->dep.cb = alias_device_cb;
  83
  84         return &alias->dev;
  85 }
  86
  87 static void alias_device_free(struct device *dev)
  88 {
  89         struct alias_device *alias;
  90
  91         alias = container_of(dev, struct alias_device, dev);
  92         avl_delete(&aliases, &alias->avl);
  93         free(alias);
  94 }
  95
  96 static const struct device_type alias_device_type = {
  97         .name = "Network alias",
  98         .create = alias_device_create,
  99         .free = alias_device_free,
 100 };
 101
 102 void
 103 alias_notify_device(const char *name, struct device *dev)
 104 {
 105         struct alias_device *alias;
 106
 107         device_lock();
 108
 109         alias = avl_find_element(&aliases, name, alias, avl);
 110         if (!alias)
 111                 goto out;
 112
 113         alias->cleanup = !dev;
 114         if (dev) {
 115                 if (dev != alias->dep.dev) {
 116                         device_remove_user(&alias->dep);
 117                         strcpy(alias->dev.ifname, dev->ifname);
 118                         device_add_user(&alias->dep, dev);
 119                         alias->dev.hidden = false;
 120                         device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
 121                 }
 122         }
 123
 124         if (!dev && alias->dep.dev && !alias->dep.dev->active) {
 125                 device_remove_user(&alias->dep);
 126                 alias->dev.hidden = true;
 127                 alias->dev.ifname[0] = 0;
 128                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
 129         }
 130
 131 out:
 132         device_unlock();
 133 }
 134
 135 struct device *
 136 device_alias_get(const char *name)
 137 {
 138         struct alias_device *alias;
 139
 140         alias = avl_find_element(&aliases, name, alias, avl);
 141         if (alias)
 142                 return &alias->dev;
 143
 144         return alias_device_create(name, NULL);
 145 }
 146
 147 static void __init alias_init(void)
 148 {
 149         avl_init(&aliases, avl_strcmp, false, NULL);
 150 }