af_netrom.c

linux 内核源代码

/*
 * 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 Jonathan Naylor G4KLX ([e-mail])
 * Copyright Alan Cox GW4PTS ([e-mail])
 * Copyright Darryl Miles G7LED ([e-mail])
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/stat.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <net/netrom.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/ip.h>
#include <net/tcp_states.h>
#include <net/arp.h>
#include <linux/init.h>

static int nr_ndevs = 4;

int sysctl_netrom_default_path_quality            = NR_DEFAULT_QUAL;
int sysctl_netrom_obsolescence_count_initialiser  = NR_DEFAULT_OBS;
int sysctl_netrom_network_ttl_initialiser         = NR_DEFAULT_TTL;
int sysctl_netrom_transport_timeout               = NR_DEFAULT_T1;
int sysctl_netrom_transport_maximum_tries         = NR_DEFAULT_N2;
int sysctl_netrom_transport_acknowledge_delay     = NR_DEFAULT_T2;
int sysctl_netrom_transport_busy_delay            = NR_DEFAULT_T4;
int sysctl_netrom_transport_requested_window_size = NR_DEFAULT_WINDOW;
int sysctl_netrom_transport_no_activity_timeout   = NR_DEFAULT_IDLE;
int sysctl_netrom_routing_control                 = NR_DEFAULT_ROUTING;
int sysctl_netrom_link_fails_count                = NR_DEFAULT_FAILS;
int sysctl_netrom_reset_circuit                   = NR_DEFAULT_RESET;

static unsigned short circuit = 0x101;

static HLIST_HEAD(nr_list);
static DEFINE_SPINLOCK(nr_list_lock);

static const struct proto_ops nr_proto_ops;

/*
 * NETROM network devices are virtual network devices encapsulating NETROM
 * frames into AX.25 which will be sent through an AX.25 device, so form a
 * special "super class" of normal net devices; split their locks off into a
 * separate class since they always nest.
 */
static struct lock_class_key nr_netdev_xmit_lock_key;

/*
 *	Socket removal during an interrupt is now safe.
 */
static void nr_remove_socket(struct sock *sk)
{
	spin_lock_bh(&nr_list_lock);
	sk_del_node_init(sk);
	spin_unlock_bh(&nr_list_lock);
}

/*
 *	Kill all bound sockets on a dropped device.
 */
static void nr_kill_by_device(struct net_device *dev)
{
	struct sock *s;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &nr_list)
		if (nr_sk(s)->device == dev)
			nr_disconnect(s, ENETUNREACH);
	spin_unlock_bh(&nr_list_lock);
}

/*
 *	Handle device status changes.
 */
static int nr_device_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct net_device *dev = (struct net_device *)ptr;

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	if (event != NETDEV_DOWN)
		return NOTIFY_DONE;

	nr_kill_by_device(dev);
	nr_rt_device_down(dev);

	return NOTIFY_DONE;
}

/*
 *	Add a socket to the bound sockets list.
 */
static void nr_insert_socket(struct sock *sk)
{
	spin_lock_bh(&nr_list_lock);
	sk_add_node(sk, &nr_list);
	spin_unlock_bh(&nr_list_lock);
}

/*
 *	Find a socket that wants to accept the Connect Request we just
 *	received.
 */
static struct sock *nr_find_listener(ax25_address *addr)
{
	struct sock *s;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &nr_list)
		if (!ax25cmp(&nr_sk(s)->source_addr, addr) &&
		    s->sk_state == TCP_LISTEN) {
			bh_lock_sock(s);
			goto found;
		}
	s = NULL;
found:
	spin_unlock_bh(&nr_list_lock);
	return s;
}

/*
 *	Find a connected NET/ROM socket given my circuit IDs.
 */
static struct sock *nr_find_socket(unsigned char index, unsigned char id)
{
	struct sock *s;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &nr_list) {
		struct nr_sock *nr = nr_sk(s);

		if (nr->my_index == index && nr->my_id == id) {
			bh_lock_sock(s);
			goto found;
		}
	}
	s = NULL;
found:
	spin_unlock_bh(&nr_list_lock);
	return s;
}

/*
 *	Find a connected NET/ROM socket given their circuit IDs.
 */
static struct sock *nr_find_peer(unsigned char index, unsigned char id,
	ax25_address *dest)
{
	struct sock *s;
	struct hlist_node *node;

	spin_lock_bh(&nr_list_lock);
	sk_for_each(s, node, &nr_list) {
		struct nr_sock *nr = nr_sk(s);

		if (nr->your_index == index && nr->your_id == id &&
		    !ax25cmp(&nr->dest_addr, dest)) {
			bh_lock_sock(s);
			goto found;
		}
	}
	s = NULL;
found:
	spin_unlock_bh(&nr_list_lock);
	return s;
}

/*
 *	Find next free circuit ID.
 */
static unsigned short nr_find_next_circuit(void)
{
	unsigned short id = circuit;
	unsigned char i, j;
	struct sock *sk;

	for (;;) {
		i = id / 256;
		j = id % 256;

		if (i != 0 && j != 0) {
			if ((sk=nr_find_socket(i, j)) == NULL)
				break;
			bh_unlock_sock(sk);
		}

		id++;
	}

	return id;
}

/*
 *	Deferred destroy.
 */
void nr_destroy_socket(struct sock *);

/*
 *	Handler for deferred kills.
 */
static void nr_destroy_timer(unsigned long data)
{
	struct sock *sk=(struct sock *)data;
	bh_lock_sock(sk);
	sock_hold(sk);
	nr_destroy_socket(sk);
	bh_unlock_sock(sk);
	sock_put(sk);
}

/*
 *	This is called from user mode and the timers. Thus it protects itself
 *	against interrupt users but doesn't worry about being called during
 *	work. Once it is removed from the queue no interrupt or bottom half
 *	will touch it and we are (fairly 8-) ) safe.
 */
void nr_destroy_socket(struct sock *sk)
{
	struct sk_buff *skb;

	nr_remove_socket(sk);

	nr_stop_heartbeat(sk);
	nr_stop_t1timer(sk);
	nr_stop_t2timer(sk);
	nr_stop_t4timer(sk);
	nr_stop_idletimer(sk);

	nr_clear_queues(sk);		/* Flush the queues */

	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
		if (skb->sk != sk) { /* A pending connection */
			/* Queue the unaccepted socket for death */
			sock_set_flag(skb->sk, SOCK_DEAD);
			nr_start_heartbeat(skb->sk);
			nr_sk(skb->sk)->state = NR_STATE_0;
		}

		kfree_skb(skb);
	}

	if (atomic_read(&sk->sk_wmem_alloc) ||
	    atomic_read(&sk->sk_rmem_alloc)) {
		/* Defer: outstanding buffers */
		sk->sk_timer.function = nr_destroy_timer;
		sk->sk_timer.expires  = jiffies + 2 * HZ;
		add_timer(&sk->sk_timer);
	} else
		sock_put(sk);
}

/*
 *	Handling for system calls applied via the various interfaces to a
 *	NET/ROM socket object.
 */

static int nr_setsockopt(struct socket *sock, int level, int optname,
	char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	struct nr_sock *nr = nr_sk(sk);
	int opt;

	if (level != SOL_NETROM)
		return -ENOPROTOOPT;

	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(opt, (int __user *)optval))
		return -EFAULT;

	switch (optname) {
	case NETROM_T1:
		if (opt < 1)
			return -EINVAL;
		nr->t1 = opt * HZ;
		return 0;

	case NETROM_T2:
		if (opt < 1)
			return -EINVAL;
		nr->t2 = opt * HZ;
		return 0;

	case NETROM_N2:
		if (opt < 1 || opt > 31)
			return -EINVAL;
		nr->n2 = opt;
		return 0;

	case NETROM_T4:
		if (opt < 1)
			return -EINVAL;
		nr->t4 = opt * HZ;
		return 0;

	case NETROM_IDLE:
		if (opt < 0)
			return -EINVAL;
		nr->idle = opt * 60 * HZ;
		return 0;

	default:
		return -ENOPROTOOPT;
	}
}

static int nr_getsockopt(struct socket *sock, int level, int optname,
	char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct nr_sock *nr = nr_sk(sk);
	int val = 0;
	int len;

	if (level != SOL_NETROM)
		return -ENOPROTOOPT;

	if (get_user(len, optlen))
		return -EFAULT;

	if (len < 0)
		return -EINVAL;

	switch (optname) {
	case NETROM_T1:
		val = nr->t1 / HZ;
		break;

	case NETROM_T2:
		val = nr->t2 / HZ;
		break;

	case NETROM_N2:
		val = nr->n2;
		break;

	case NETROM_T4:
		val = nr->t4 / HZ;
		break;

	case NETROM_IDLE:
		val = nr->idle / (60 * HZ);
		break;

	default:
		return -ENOPROTOOPT;
	}

	len = min_t(unsigned int, len, sizeof(int));

	if (put_user(len, optlen))
		return -EFAULT;

	return copy_to_user(optval, &val, len) ? -EFAULT : 0;
}

static int nr_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;

	lock_sock(sk);
	if (sk->sk_state != TCP_LISTEN) {
		memset(&nr_sk(sk)->user_addr, 0, AX25_ADDR_LEN);
		sk->sk_max_ack_backlog = backlog;
		sk->sk_state           = TCP_LISTEN;
		release_sock(sk);
		return 0;
	}
	release_sock(sk);

	return -EOPNOTSUPP;
}

static struct proto nr_proto = {
	.name	  = "NETROM",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct nr_sock),
};

static int nr_create(struct net *net, struct socket *sock, int protocol)
{
	struct sock *sk;
	struct nr_sock *nr;

	if (net != &init_net)
		return -EAFNOSUPPORT;

	if (sock->type != SOCK_SEQPACKET || protocol != 0)
		return -ESOCKTNOSUPPORT;

	sk = sk_alloc(net, PF_NETROM, GFP_ATOMIC, &nr_proto);
	if (sk  == NULL)
		return -ENOMEM;

	nr = nr_sk(sk);

	sock_init_data(sock, sk);

	sock->ops    = &nr_proto_ops;
	sk->sk_protocol = protocol;

	skb_queue_head_init(&nr->ack_queue);
	skb_queue_head_init(&nr->reseq_queue);
	skb_queue_head_init(&nr->frag_queue);

	nr_init_timers(sk);

	nr->t1     =
		msecs_to_jiffies(sysctl_netrom_transport_timeout);
	nr->t2     =
		msecs_to_jiffies(sysctl_netrom_transport_acknowledge_delay);
	nr->n2     =
		msecs_to_jiffies(sysctl_netrom_transport_maximum_tries);
	nr->t4     =
		msecs_to_jiffies(sysctl_netrom_transport_busy_delay);
	nr->idle   =
		msecs_to_jiffies(sysctl_netrom_transport_no_activity_timeout);
	nr->window = sysctl_netrom_transport_requested_window_size;

	nr->bpqext = 1;
	nr->state  = NR_STATE_0;

	return 0;
}

static struct sock *nr_make_new(struct sock *osk)
{
	struct sock *sk;
	struct nr_sock *nr, *onr;

	if (osk->sk_type != SOCK_SEQPACKET)
		return NULL;

	sk = sk_alloc(osk->sk_net, PF_NETROM, GFP_ATOMIC, osk->sk_prot);
	if (sk == NULL)
		return NULL;

	nr = nr_sk(sk);

	sock_init_data(NULL, sk);

	sk->sk_type     = osk->sk_type;
	sk->sk_socket   = osk->sk_socket;
	sk->sk_priority = osk->sk_priority;
	sk->sk_protocol = osk->sk_protocol;
	sk->sk_rcvbuf   = osk->sk_rcvbuf;
	sk->sk_sndbuf   = osk->sk_sndbuf;
	sk->sk_state    = TCP_ESTABLISHED;
	sk->sk_sleep    = osk->sk_sleep;
	sock_copy_flags(sk, osk);

	skb_queue_head_init(&nr->ack_queue);
	skb_queue_head_init(&nr->reseq_queue);
	skb_queue_head_init(&nr->frag_queue);

	nr_init_timers(sk);

	onr = nr_sk(osk);

	nr->t1      = onr->t1;
	nr->t2      = onr->t2;
	nr->n2      = onr->n2;
	nr->t4      = onr->t4;
	nr->idle    = onr->idle;
	nr->window  = onr->window;

	nr->device  = onr->device;
	nr->bpqext  = onr->bpqext;

	return sk;
}