linux/net/ax25/ax25_iface.c
Ralf Baechle 95ff9f4d3c [AX.25]: Fix locking of ax25 protocol function list.
Delivery of AX.25 frame to the layer 3 protocols happens in softirq
context so locking needs to be bh-proof.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-07-12 13:58:40 -07:00

279 lines
6.2 KiB
C

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
static struct protocol_struct {
struct protocol_struct *next;
unsigned int pid;
int (*func)(struct sk_buff *, ax25_cb *);
} *protocol_list = NULL;
static DEFINE_RWLOCK(protocol_list_lock);
static struct linkfail_struct {
struct linkfail_struct *next;
void (*func)(ax25_cb *, int);
} *linkfail_list = NULL;
static DEFINE_SPINLOCK(linkfail_lock);
static struct listen_struct {
struct listen_struct *next;
ax25_address callsign;
struct net_device *dev;
} *listen_list = NULL;
static DEFINE_SPINLOCK(listen_lock);
int ax25_protocol_register(unsigned int pid,
int (*func)(struct sk_buff *, ax25_cb *))
{
struct protocol_struct *protocol;
if (pid == AX25_P_TEXT || pid == AX25_P_SEGMENT)
return 0;
#ifdef CONFIG_INET
if (pid == AX25_P_IP || pid == AX25_P_ARP)
return 0;
#endif
if ((protocol = kmalloc(sizeof(*protocol), GFP_ATOMIC)) == NULL)
return 0;
protocol->pid = pid;
protocol->func = func;
write_lock_bh(&protocol_list_lock);
protocol->next = protocol_list;
protocol_list = protocol;
write_unlock_bh(&protocol_list_lock);
return 1;
}
EXPORT_SYMBOL(ax25_protocol_register);
void ax25_protocol_release(unsigned int pid)
{
struct protocol_struct *s, *protocol;
write_lock_bh(&protocol_list_lock);
protocol = protocol_list;
if (protocol == NULL) {
write_unlock_bh(&protocol_list_lock);
return;
}
if (protocol->pid == pid) {
protocol_list = protocol->next;
write_unlock_bh(&protocol_list_lock);
kfree(protocol);
return;
}
while (protocol != NULL && protocol->next != NULL) {
if (protocol->next->pid == pid) {
s = protocol->next;
protocol->next = protocol->next->next;
write_unlock_bh(&protocol_list_lock);
kfree(s);
return;
}
protocol = protocol->next;
}
write_unlock_bh(&protocol_list_lock);
}
EXPORT_SYMBOL(ax25_protocol_release);
int ax25_linkfail_register(void (*func)(ax25_cb *, int))
{
struct linkfail_struct *linkfail;
if ((linkfail = kmalloc(sizeof(*linkfail), GFP_ATOMIC)) == NULL)
return 0;
linkfail->func = func;
spin_lock_bh(&linkfail_lock);
linkfail->next = linkfail_list;
linkfail_list = linkfail;
spin_unlock_bh(&linkfail_lock);
return 1;
}
EXPORT_SYMBOL(ax25_linkfail_register);
void ax25_linkfail_release(void (*func)(ax25_cb *, int))
{
struct linkfail_struct *s, *linkfail;
spin_lock_bh(&linkfail_lock);
linkfail = linkfail_list;
if (linkfail == NULL) {
spin_unlock_bh(&linkfail_lock);
return;
}
if (linkfail->func == func) {
linkfail_list = linkfail->next;
spin_unlock_bh(&linkfail_lock);
kfree(linkfail);
return;
}
while (linkfail != NULL && linkfail->next != NULL) {
if (linkfail->next->func == func) {
s = linkfail->next;
linkfail->next = linkfail->next->next;
spin_unlock_bh(&linkfail_lock);
kfree(s);
return;
}
linkfail = linkfail->next;
}
spin_unlock_bh(&linkfail_lock);
}
EXPORT_SYMBOL(ax25_linkfail_release);
int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
{
struct listen_struct *listen;
if (ax25_listen_mine(callsign, dev))
return 0;
if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
return 0;
listen->callsign = *callsign;
listen->dev = dev;
spin_lock_bh(&listen_lock);
listen->next = listen_list;
listen_list = listen;
spin_unlock_bh(&listen_lock);
return 1;
}
EXPORT_SYMBOL(ax25_listen_register);
void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
{
struct listen_struct *s, *listen;
spin_lock_bh(&listen_lock);
listen = listen_list;
if (listen == NULL) {
spin_unlock_bh(&listen_lock);
return;
}
if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
listen_list = listen->next;
spin_unlock_bh(&listen_lock);
kfree(listen);
return;
}
while (listen != NULL && listen->next != NULL) {
if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
s = listen->next;
listen->next = listen->next->next;
spin_unlock_bh(&listen_lock);
kfree(s);
return;
}
listen = listen->next;
}
spin_unlock_bh(&listen_lock);
}
EXPORT_SYMBOL(ax25_listen_release);
int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
{
int (*res)(struct sk_buff *, ax25_cb *) = NULL;
struct protocol_struct *protocol;
read_lock(&protocol_list_lock);
for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
if (protocol->pid == pid) {
res = protocol->func;
break;
}
read_unlock(&protocol_list_lock);
return res;
}
int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
{
struct listen_struct *listen;
spin_lock_bh(&listen_lock);
for (listen = listen_list; listen != NULL; listen = listen->next)
if (ax25cmp(&listen->callsign, callsign) == 0 && (listen->dev == dev || listen->dev == NULL)) {
spin_unlock_bh(&listen_lock);
return 1;
}
spin_unlock_bh(&listen_lock);
return 0;
}
void ax25_link_failed(ax25_cb *ax25, int reason)
{
struct linkfail_struct *linkfail;
spin_lock_bh(&linkfail_lock);
for (linkfail = linkfail_list; linkfail != NULL; linkfail = linkfail->next)
(linkfail->func)(ax25, reason);
spin_unlock_bh(&linkfail_lock);
}
int ax25_protocol_is_registered(unsigned int pid)
{
struct protocol_struct *protocol;
int res = 0;
read_lock_bh(&protocol_list_lock);
for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
if (protocol->pid == pid) {
res = 1;
break;
}
read_unlock_bh(&protocol_list_lock);
return res;
}