net/ax25/ax25_dev.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/types.h>
   8 #include <linux/socket.h>
   9 #include <linux/slab.h>
  10 #include <linux/in.h>
  11 #include <linux/kernel.h>
  12 #include <linux/timer.h>
  13 #include <linux/string.h>
  14 #include <linux/sockios.h>
  15 #include <linux/net.h>
  16 #include <linux/spinlock.h>
  17 #include <net/ax25.h>
  18 #include <linux/inet.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/if_arp.h>
  21 #include <linux/skbuff.h>
  22 #include <net/sock.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/mm.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/init.h>
  28
  29 ax25_dev *ax25_dev_list;
  30 DEFINE_SPINLOCK(ax25_dev_lock);
  31
  32 ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
  33 {
  34         ax25_dev *ax25_dev, *res = NULL;
  35
  36         spin_lock_bh(&ax25_dev_lock);
  37         for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
  38                 if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) {
  39                         res = ax25_dev;
  40                         ax25_dev_hold(ax25_dev);
  41                 }
  42         spin_unlock_bh(&ax25_dev_lock);
  43
  44         return res;
  45 }
  46
  47 /*
  48  *      This is called when an interface is brought up. These are
  49  *      reasonable defaults.
  50  */
  51 void ax25_dev_device_up(struct net_device *dev)
  52 {
  53         ax25_dev *ax25_dev;
  54
  55         if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
  56                 printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
  57                 return;
  58         }
  59
  60         refcount_set(&ax25_dev->refcount, 1);
  61         dev->ax25_ptr     = ax25_dev;
  62         ax25_dev->dev     = dev;
  63         dev_hold_track(dev, &ax25_dev->dev_tracker, GFP_ATOMIC);
  64         ax25_dev->forward = NULL;
  65
  66         ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
  67         ax25_dev->values[AX25_VALUES_AXDEFMODE] = AX25_DEF_AXDEFMODE;
  68         ax25_dev->values[AX25_VALUES_BACKOFF]   = AX25_DEF_BACKOFF;
  69         ax25_dev->values[AX25_VALUES_CONMODE]   = AX25_DEF_CONMODE;
  70         ax25_dev->values[AX25_VALUES_WINDOW]    = AX25_DEF_WINDOW;
  71         ax25_dev->values[AX25_VALUES_EWINDOW]   = AX25_DEF_EWINDOW;
  72         ax25_dev->values[AX25_VALUES_T1]        = AX25_DEF_T1;
  73         ax25_dev->values[AX25_VALUES_T2]        = AX25_DEF_T2;
  74         ax25_dev->values[AX25_VALUES_T3]        = AX25_DEF_T3;
  75         ax25_dev->values[AX25_VALUES_IDLE]      = AX25_DEF_IDLE;
  76         ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
  77         ax25_dev->values[AX25_VALUES_PACLEN]    = AX25_DEF_PACLEN;
  78         ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
  79         ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
  80
  81 #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
  82         ax25_ds_setup_timer(ax25_dev);
  83 #endif
  84
  85         spin_lock_bh(&ax25_dev_lock);
  86         ax25_dev->next = ax25_dev_list;
  87         ax25_dev_list  = ax25_dev;
  88         spin_unlock_bh(&ax25_dev_lock);
  89         ax25_dev_hold(ax25_dev);
  90
  91         ax25_register_dev_sysctl(ax25_dev);
  92 }
  93
  94 void ax25_dev_device_down(struct net_device *dev)
  95 {
  96         ax25_dev *s, *ax25_dev;
  97
  98         if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
  99                 return;
 100
 101         ax25_unregister_dev_sysctl(ax25_dev);
 102
 103         spin_lock_bh(&ax25_dev_lock);
 104
 105 #ifdef CONFIG_AX25_DAMA_SLAVE
 106         ax25_ds_del_timer(ax25_dev);
 107 #endif
 108
 109         /*
 110          *      Remove any packet forwarding that points to this device.
 111          */
 112         for (s = ax25_dev_list; s != NULL; s = s->next)
 113                 if (s->forward == dev)
 114                         s->forward = NULL;
 115
 116         if ((s = ax25_dev_list) == ax25_dev) {
 117                 ax25_dev_list = s->next;
 118                 goto unlock_put;
 119         }
 120
 121         while (s != NULL && s->next != NULL) {
 122                 if (s->next == ax25_dev) {
 123                         s->next = ax25_dev->next;
 124                         goto unlock_put;
 125                 }
 126
 127                 s = s->next;
 128         }
 129         spin_unlock_bh(&ax25_dev_lock);
 130         dev->ax25_ptr = NULL;
 131         ax25_dev_put(ax25_dev);
 132         return;
 133
 134 unlock_put:
 135         spin_unlock_bh(&ax25_dev_lock);
 136         ax25_dev_put(ax25_dev);
 137         dev->ax25_ptr = NULL;
 138         dev_put_track(dev, &ax25_dev->dev_tracker);
 139         ax25_dev_put(ax25_dev);
 140 }
 141
 142 int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
 143 {
 144         ax25_dev *ax25_dev, *fwd_dev;
 145
 146         if ((ax25_dev = ax25_addr_ax25dev(&fwd->port_from)) == NULL)
 147                 return -EINVAL;
 148
 149         switch (cmd) {
 150         case SIOCAX25ADDFWD:
 151                 fwd_dev = ax25_addr_ax25dev(&fwd->port_to);
 152                 if (!fwd_dev) {
 153                         ax25_dev_put(ax25_dev);
 154                         return -EINVAL;
 155                 }
 156                 if (ax25_dev->forward) {
 157                         ax25_dev_put(fwd_dev);
 158                         ax25_dev_put(ax25_dev);
 159                         return -EINVAL;
 160                 }
 161                 ax25_dev->forward = fwd_dev->dev;
 162                 ax25_dev_put(fwd_dev);
 163                 ax25_dev_put(ax25_dev);
 164                 break;
 165
 166         case SIOCAX25DELFWD:
 167                 if (!ax25_dev->forward) {
 168                         ax25_dev_put(ax25_dev);
 169                         return -EINVAL;
 170                 }
 171                 ax25_dev->forward = NULL;
 172                 ax25_dev_put(ax25_dev);
 173                 break;
 174
 175         default:
 176                 ax25_dev_put(ax25_dev);
 177                 return -EINVAL;
 178         }
 179
 180         return 0;
 181 }
 182
 183 struct net_device *ax25_fwd_dev(struct net_device *dev)
 184 {
 185         ax25_dev *ax25_dev;
 186
 187         if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
 188                 return dev;
 189
 190         if (ax25_dev->forward == NULL)
 191                 return dev;
 192
 193         return ax25_dev->forward;
 194 }
 195
 196 /*
 197  *      Free all memory associated with device structures.
 198  */
 199 void __exit ax25_dev_free(void)
 200 {
 201         ax25_dev *s, *ax25_dev;
 202
 203         spin_lock_bh(&ax25_dev_lock);
 204         ax25_dev = ax25_dev_list;
 205         while (ax25_dev != NULL) {
 206                 s        = ax25_dev;
 207                 dev_put_track(ax25_dev->dev, &ax25_dev->dev_tracker);
 208                 ax25_dev = ax25_dev->next;
 209                 kfree(s);
 210         }
 211         ax25_dev_list = NULL;
 212         spin_unlock_bh(&ax25_dev_lock);
 213 }