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 struct device *
  52 alias_device_create(const char *name, struct blob_attr *attr)
  53 {
  54         struct alias_device *alias;
  55
  56         alias = calloc(1, sizeof(*alias) + strlen(name) + 1);
  57         strcpy(alias->name, name);
  58         alias->dev.set_state = alias_device_set_state;
  59         alias->dev.hidden = true;
  60         device_init_virtual(&alias->dev, &alias_device_type, NULL);
  61         alias->avl.key = alias->name;
  62         avl_insert(&aliases, &alias->avl);
  63
  64         return &alias->dev;
  65 }
  66
  67 static void alias_device_free(struct device *dev)
  68 {
  69         struct alias_device *alias;
  70
  71         alias = container_of(dev, struct alias_device, dev);
  72         avl_delete(&aliases, &alias->avl);
  73         free(alias);
  74 }
  75
  76 static const struct device_type alias_device_type = {
  77         .name = "Network alias",
  78         .create = alias_device_create,
  79         .free = alias_device_free,
  80 };
  81
  82 void
  83 alias_notify_device(const char *name, struct device *dev)
  84 {
  85         struct alias_device *alias;
  86
  87         device_lock();
  88
  89         alias = avl_find_element(&aliases, name, alias, avl);
  90         if (!alias)
  91                 return;
  92
  93         alias->cleanup = !dev;
  94         if (dev) {
  95                 if (dev != alias->dep.dev) {
  96                         device_remove_user(&alias->dep);
  97                         strcpy(alias->dev.ifname, dev->ifname);
  98                         device_add_user(&alias->dep, dev);
  99                         alias->dev.hidden = false;
 100                         device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
 101                 }
 102         }
 103
 104         device_set_present(&alias->dev, !!dev);
 105
 106         if (!dev && alias->dep.dev && !alias->dep.dev->active) {
 107                 device_remove_user(&alias->dep);
 108                 alias->dev.hidden = true;
 109                 alias->dev.ifname[0] = 0;
 110                 device_broadcast_event(&alias->dev, DEV_EVENT_UPDATE_IFNAME);
 111         }
 112
 113         device_unlock();
 114 }
 115
 116 struct device *
 117 device_alias_get(const char *name)
 118 {
 119         struct alias_device *alias;
 120
 121         alias = avl_find_element(&aliases, name, alias, avl);
 122         if (alias)
 123                 return &alias->dev;
 124
 125         return alias_device_create(name, NULL);
 126 }
 127
 128 static void __init alias_init(void)
 129 {
 130         avl_init(&aliases, avl_strcmp, false, NULL);
 131 }