net/ax25/ax25_iface.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/in.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/timer.h>
  14 #include <linux/string.h>
  15 #include <linux/sockios.h>
  16 #include <linux/net.h>
  17 #include <linux/slab.h>
  18 #include <net/ax25.h>
  19 #include <linux/inet.h>
  20 #include <linux/netdevice.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
  28 static struct ax25_protocol *protocol_list;
  29 static DEFINE_RWLOCK(protocol_list_lock);
  30
  31 static HLIST_HEAD(ax25_linkfail_list);
  32 static DEFINE_SPINLOCK(linkfail_lock);
  33
  34 static struct listen_struct {
  35         struct listen_struct *next;
  36         ax25_address  callsign;
  37         struct net_device *dev;
  38 } *listen_list = NULL;
  39 static DEFINE_SPINLOCK(listen_lock);
  40
  41 /*
  42  * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
  43  * AX25_P_IP or AX25_P_ARP ...
  44  */
  45 void ax25_register_pid(struct ax25_protocol *ap)
  46 {
  47         write_lock_bh(&protocol_list_lock);
  48         ap->next = protocol_list;
  49         protocol_list = ap;
  50         write_unlock_bh(&protocol_list_lock);
  51 }
  52
  53 EXPORT_SYMBOL_GPL(ax25_register_pid);
  54
  55 void ax25_protocol_release(unsigned int pid)
  56 {
  57         struct ax25_protocol *protocol;
  58
  59         write_lock_bh(&protocol_list_lock);
  60         protocol = protocol_list;
  61         if (protocol == NULL)
  62                 goto out;
  63
  64         if (protocol->pid == pid) {
  65                 protocol_list = protocol->next;
  66                 goto out;
  67         }
  68
  69         while (protocol != NULL && protocol->next != NULL) {
  70                 if (protocol->next->pid == pid) {
  71                         protocol->next = protocol->next->next;
  72                         goto out;
  73                 }
  74
  75                 protocol = protocol->next;
  76         }
  77 out:
  78         write_unlock_bh(&protocol_list_lock);
  79 }
  80
  81 EXPORT_SYMBOL(ax25_protocol_release);
  82
  83 void ax25_linkfail_register(struct ax25_linkfail *lf)
  84 {
  85         spin_lock_bh(&linkfail_lock);
  86         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  87         spin_unlock_bh(&linkfail_lock);
  88 }
  89
  90 EXPORT_SYMBOL(ax25_linkfail_register);
  91
  92 void ax25_linkfail_release(struct ax25_linkfail *lf)
  93 {
  94         spin_lock_bh(&linkfail_lock);
  95         hlist_del_init(&lf->lf_node);
  96         spin_unlock_bh(&linkfail_lock);
  97 }
  98
  99 EXPORT_SYMBOL(ax25_linkfail_release);
 100
 101 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 102 {
 103         struct listen_struct *listen;
 104
 105         if (ax25_listen_mine(callsign, dev))
 106                 return 0;
 107
 108         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 109                 return -ENOMEM;
 110
 111         listen->callsign = *callsign;
 112         listen->dev      = dev;
 113
 114         spin_lock_bh(&listen_lock);
 115         listen->next = listen_list;
 116         listen_list  = listen;
 117         spin_unlock_bh(&listen_lock);
 118
 119         return 0;
 120 }
 121
 122 EXPORT_SYMBOL(ax25_listen_register);
 123
 124 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 125 {
 126         struct listen_struct *s, *listen;
 127
 128         spin_lock_bh(&listen_lock);
 129         listen = listen_list;
 130         if (listen == NULL) {
 131                 spin_unlock_bh(&listen_lock);
 132                 return;
 133         }
 134
 135         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 136                 listen_list = listen->next;
 137                 spin_unlock_bh(&listen_lock);
 138                 kfree(listen);
 139                 return;
 140         }
 141
 142         while (listen != NULL && listen->next != NULL) {
 143                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 144                         s = listen->next;
 145                         listen->next = listen->next->next;
 146                         spin_unlock_bh(&listen_lock);
 147                         kfree(s);
 148                         return;
 149                 }
 150
 151                 listen = listen->next;
 152         }
 153         spin_unlock_bh(&listen_lock);
 154 }
 155
 156 EXPORT_SYMBOL(ax25_listen_release);
 157
 158 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 159 {
 160         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 161         struct ax25_protocol *protocol;
 162
 163         read_lock(&protocol_list_lock);
 164         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 165                 if (protocol->pid == pid) {
 166                         res = protocol->func;
 167                         break;
 168                 }
 169         read_unlock(&protocol_list_lock);
 170
 171         return res;
 172 }
 173
 174 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 175 {
 176         struct listen_struct *listen;
 177
 178         spin_lock_bh(&listen_lock);
 179         for (listen = listen_list; listen != NULL; listen = listen->next)
 180                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 181                     (listen->dev == dev || listen->dev == NULL)) {
 182                         spin_unlock_bh(&listen_lock);
 183                         return 1;
 184         }
 185         spin_unlock_bh(&listen_lock);
 186
 187         return 0;
 188 }
 189
 190 void ax25_link_failed(ax25_cb *ax25, int reason)
 191 {
 192         struct ax25_linkfail *lf;
 193
 194         spin_lock_bh(&linkfail_lock);
 195         hlist_for_each_entry(lf, &ax25_linkfail_list, lf_node)
 196                 lf->func(ax25, reason);
 197         spin_unlock_bh(&linkfail_lock);
 198 }
 199
 200 int ax25_protocol_is_registered(unsigned int pid)
 201 {
 202         struct ax25_protocol *protocol;
 203         int res = 0;
 204
 205         read_lock_bh(&protocol_list_lock);
 206         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 207                 if (protocol->pid == pid) {
 208                         res = 1;
 209                         break;
 210                 }
 211         read_unlock_bh(&protocol_list_lock);
 212
 213         return res;
 214 }