af_ipx.c

linux 内核源代码

/*
 *	Implements an IPX socket layer.
 *
 *	This code is derived from work by
 *		Ross Biro	: 	Writing the original IP stack
 *		Fred Van Kempen :	Tidying up the TCP/IP
 *
 *	Many thanks go to Keith Baker, Institute For Industrial Information
 *	Technology Ltd, Swansea University for allowing me to work on this
 *	in my own time even though it was in some ways related to commercial
 *	work I am currently employed to do there.
 *
 *	All the material in this file is subject to the Gnu license version 2.
 *	Neither Alan Cox nor the Swansea University Computer Society admit
 *	liability nor provide warranty for any of this software. This material
 *	is provided as is and at no charge.
 *
 *	Portions Copyright (c) 2000-2003 Conectiva, Inc. <[e-mail]>
 *	Neither Arnaldo Carvalho de Melo nor Conectiva, Inc. admit liability nor
 *	provide warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 *
 * 	Portions Copyright (c) 1995 Caldera, Inc. <[e-mail]>
 *	Neither Greg Page nor Caldera, Inc. admit liability nor provide
 *	warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 *
 *	See net/ipx/ChangeLog.
 */

#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/ipx.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/uio.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/termios.h>

#include <net/ipx.h>
#include <net/p8022.h>
#include <net/psnap.h>
#include <net/sock.h>
#include <net/tcp_states.h>

#include <asm/uaccess.h>

#ifdef CONFIG_SYSCTL
extern void ipx_register_sysctl(void);
extern void ipx_unregister_sysctl(void);
#else
#define ipx_register_sysctl()
#define ipx_unregister_sysctl()
#endif

/* Configuration Variables */
static unsigned char ipxcfg_max_hops = 16;
static char ipxcfg_auto_select_primary;
static char ipxcfg_auto_create_interfaces;
int sysctl_ipx_pprop_broadcasting = 1;

/* Global Variables */
static struct datalink_proto *p8022_datalink;
static struct datalink_proto *pEII_datalink;
static struct datalink_proto *p8023_datalink;
static struct datalink_proto *pSNAP_datalink;

static const struct proto_ops ipx_dgram_ops;

LIST_HEAD(ipx_interfaces);
DEFINE_SPINLOCK(ipx_interfaces_lock);

struct ipx_interface *ipx_primary_net;
struct ipx_interface *ipx_internal_net;

extern int ipxrtr_add_route(__be32 network, struct ipx_interface *intrfc,
			    unsigned char *node);
extern void ipxrtr_del_routes(struct ipx_interface *intrfc);
extern int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
			       struct iovec *iov, size_t len, int noblock);
extern int ipxrtr_route_skb(struct sk_buff *skb);
extern struct ipx_route *ipxrtr_lookup(__be32 net);
extern int ipxrtr_ioctl(unsigned int cmd, void __user *arg);

struct ipx_interface *ipx_interfaces_head(void)
{
	struct ipx_interface *rc = NULL;

	if (!list_empty(&ipx_interfaces))
		rc = list_entry(ipx_interfaces.next,
				struct ipx_interface, node);
	return rc;
}

static void ipxcfg_set_auto_select(char val)
{
	ipxcfg_auto_select_primary = val;
	if (val && !ipx_primary_net)
		ipx_primary_net = ipx_interfaces_head();
}

static int ipxcfg_get_config_data(struct ipx_config_data __user *arg)
{
	struct ipx_config_data vals;

	vals.ipxcfg_auto_create_interfaces = ipxcfg_auto_create_interfaces;
	vals.ipxcfg_auto_select_primary	   = ipxcfg_auto_select_primary;

	return copy_to_user(arg, &vals, sizeof(vals)) ? -EFAULT : 0;
}

/*
 * Note: Sockets may not be removed _during_ an interrupt or inet_bh
 * handler using this technique. They can be added although we do not
 * use this facility.
 */

static void ipx_remove_socket(struct sock *sk)
{
	/* Determine interface with which socket is associated */
	struct ipx_interface *intrfc = ipx_sk(sk)->intrfc;

	if (!intrfc)
		goto out;

	ipxitf_hold(intrfc);
	spin_lock_bh(&intrfc->if_sklist_lock);
	sk_del_node_init(sk);
	spin_unlock_bh(&intrfc->if_sklist_lock);
	ipxitf_put(intrfc);
out:
	return;
}

static void ipx_destroy_socket(struct sock *sk)
{
	ipx_remove_socket(sk);
	skb_queue_purge(&sk->sk_receive_queue);
	sk_refcnt_debug_dec(sk);
	sock_put(sk);
}

/*
 * The following code is used to support IPX Interfaces (IPXITF).  An
 * IPX interface is defined by a physical device and a frame type.
 */

/* ipxitf_clear_primary_net has to be called with ipx_interfaces_lock held */

static void ipxitf_clear_primary_net(void)
{
	ipx_primary_net = NULL;
	if (ipxcfg_auto_select_primary)
		ipx_primary_net = ipx_interfaces_head();
}

static struct ipx_interface *__ipxitf_find_using_phys(struct net_device *dev,
						      __be16 datalink)
{
	struct ipx_interface *i;

	list_for_each_entry(i, &ipx_interfaces, node)
		if (i->if_dev == dev && i->if_dlink_type == datalink)
			goto out;
	i = NULL;
out:
	return i;
}

static struct ipx_interface *ipxitf_find_using_phys(struct net_device *dev,
						    __be16 datalink)
{
	struct ipx_interface *i;

	spin_lock_bh(&ipx_interfaces_lock);
	i = __ipxitf_find_using_phys(dev, datalink);
	if (i)
		ipxitf_hold(i);
	spin_unlock_bh(&ipx_interfaces_lock);
	return i;
}

struct ipx_interface *ipxitf_find_using_net(__be32 net)
{
	struct ipx_interface *i;

	spin_lock_bh(&ipx_interfaces_lock);
	if (net) {
		list_for_each_entry(i, &ipx_interfaces, node)
			if (i->if_netnum == net)
				goto hold;
		i = NULL;
		goto unlock;
	}

	i = ipx_primary_net;
	if (i)
hold:
		ipxitf_hold(i);
unlock:
	spin_unlock_bh(&ipx_interfaces_lock);
	return i;
}

/* Sockets are bound to a particular IPX interface. */
static void ipxitf_insert_socket(struct ipx_interface *intrfc, struct sock *sk)
{
	ipxitf_hold(intrfc);
	spin_lock_bh(&intrfc->if_sklist_lock);
	ipx_sk(sk)->intrfc = intrfc;
	sk_add_node(sk, &intrfc->if_sklist);
	spin_unlock_bh(&intrfc->if_sklist_lock);
	ipxitf_put(intrfc);
}

/* caller must hold intrfc->if_sklist_lock */
static struct sock *__ipxitf_find_socket(struct ipx_interface *intrfc,
					 __be16 port)
{
	struct sock *s;
	struct hlist_node *node;

	sk_for_each(s, node, &intrfc->if_sklist)
		if (ipx_sk(s)->port == port)
			goto found;
	s = NULL;
found:
	return s;
}

/* caller must hold a reference to intrfc */
static struct sock *ipxitf_find_socket(struct ipx_interface *intrfc,
					__be16 port)
{
	struct sock *s;

	spin_lock_bh(&intrfc->if_sklist_lock);
	s = __ipxitf_find_socket(intrfc, port);
	if (s)
		sock_hold(s);
	spin_unlock_bh(&intrfc->if_sklist_lock);

	return s;
}

#ifdef CONFIG_IPX_INTERN
static struct sock *ipxitf_find_internal_socket(struct ipx_interface *intrfc,
						unsigned char *ipx_node,
						__be16 port)
{
	struct sock *s;
	struct hlist_node *node;

	ipxitf_hold(intrfc);
	spin_lock_bh(&intrfc->if_sklist_lock);

	sk_for_each(s, node, &intrfc->if_sklist) {
		struct ipx_sock *ipxs = ipx_sk(s);

		if (ipxs->port == port &&
		    !memcmp(ipx_node, ipxs->node, IPX_NODE_LEN))
			goto found;
	}
	s = NULL;
found:
	spin_unlock_bh(&intrfc->if_sklist_lock);
	ipxitf_put(intrfc);
	return s;
}
#endif

static void __ipxitf_down(struct ipx_interface *intrfc)
{
	struct sock *s;
	struct hlist_node *node, *t;

	/* Delete all routes associated with this interface */
	ipxrtr_del_routes(intrfc);

	spin_lock_bh(&intrfc->if_sklist_lock);
	/* error sockets */
	sk_for_each_safe(s, node, t, &intrfc->if_sklist) {
		struct ipx_sock *ipxs = ipx_sk(s);

		s->sk_err = ENOLINK;
		s->sk_error_report(s);
		ipxs->intrfc = NULL;
		ipxs->port   = 0;
		sock_set_flag(s, SOCK_ZAPPED); /* Indicates it is no longer bound */
		sk_del_node_init(s);
	}
	INIT_HLIST_HEAD(&intrfc->if_sklist);
	spin_unlock_bh(&intrfc->if_sklist_lock);

	/* remove this interface from list */
	list_del(&intrfc->node);

	/* remove this interface from *special* networks */
	if (intrfc == ipx_primary_net)
		ipxitf_clear_primary_net();
	if (intrfc == ipx_internal_net)
		ipx_internal_net = NULL;

	if (intrfc->if_dev)
		dev_put(intrfc->if_dev);
	kfree(intrfc);
}

void ipxitf_down(struct ipx_interface *intrfc)
{
	spin_lock_bh(&ipx_interfaces_lock);
	__ipxitf_down(intrfc);
	spin_unlock_bh(&ipx_interfaces_lock);
}

static __inline__ void __ipxitf_put(struct ipx_interface *intrfc)
{
	if (atomic_dec_and_test(&intrfc->refcnt))
		__ipxitf_down(intrfc);
}

static int ipxitf_device_event(struct notifier_block *notifier,
				unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
	struct ipx_interface *i, *tmp;

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

	if (event != NETDEV_DOWN && event != NETDEV_UP)
		goto out;

	spin_lock_bh(&ipx_interfaces_lock);
	list_for_each_entry_safe(i, tmp, &ipx_interfaces, node)
		if (i->if_dev == dev) {
			if (event == NETDEV_UP)
				ipxitf_hold(i);
			else
				__ipxitf_put(i);
		}
	spin_unlock_bh(&ipx_interfaces_lock);
out:
	return NOTIFY_DONE;
}


static __exit void ipxitf_cleanup(void)
{
	struct ipx_interface *i, *tmp;

	spin_lock_bh(&ipx_interfaces_lock);
	list_for_each_entry_safe(i, tmp, &ipx_interfaces, node)
		__ipxitf_put(i);
	spin_unlock_bh(&ipx_interfaces_lock);
}

static void ipxitf_def_skb_handler(struct sock *sock, struct sk_buff *skb)
{
	if (sock_queue_rcv_skb(sock, skb) < 0)
		kfree_skb(skb);
}

/*
 * On input skb->sk is NULL. Nobody is charged for the memory.
 */

/* caller must hold a reference to intrfc */

#ifdef CONFIG_IPX_INTERN
static int ipxitf_demux_socket(struct ipx_interface *intrfc,
			       struct sk_buff *skb, int copy)
{
	struct ipxhdr *ipx = ipx_hdr(skb);
	int is_broadcast = !memcmp(ipx->ipx_dest.node, ipx_broadcast_node,
				   IPX_NODE_LEN);
	struct sock *s;
	struct hlist_node *node;
	int rc;

	spin_lock_bh(&intrfc->if_sklist_lock);

	sk_for_each(s, node, &intrfc->if_sklist) {
		struct ipx_sock *ipxs = ipx_sk(s);

		if (ipxs->port == ipx->ipx_dest.sock &&
		    (is_broadcast || !memcmp(ipx->ipx_dest.node,
					     ipxs->node, IPX_NODE_LEN))) {
			/* We found a socket to which to send */
			struct sk_buff *skb1;

			if (copy) {
				skb1 = skb_clone(skb, GFP_ATOMIC);
				rc = -ENOMEM;
				if (!skb1)
					goto out;
			} else {
				skb1 = skb;
				copy = 1; /* skb may only be used once */
			}
			ipxitf_def_skb_handler(s, skb1);

			/* On an external interface, one socket can listen */
			if (intrfc != ipx_internal_net)
				break;
		}
	}

	/* skb was solely for us, and we did not make a copy, so free it. */
	if (!copy)
		kfree_skb(skb);

	rc = 0;
out:
	spin_unlock_bh(&intrfc->if_sklist_lock);
	return rc;
}
#else
static struct sock *ncp_connection_hack(struct ipx_interface *intrfc,
					struct ipxhdr *ipx)
{
	/* The packet's target is a NCP connection handler. We want to hand it
	 * to the correct socket directly within the kernel, so that the
	 * mars_nwe packet distribution process does not have to do it. Here we
	 * only care about NCP and BURST packets.
	 *
	 * You might call this a hack, but believe me, you do not want a
	 * complete NCP layer in the kernel, and this is VERY fast as well. */
	struct sock *sk = NULL;
	int connection = 0;
	u8 *ncphdr = (u8 *)(ipx + 1);

	if (*ncphdr == 0x22 && *(ncphdr + 1) == 0x22) /* NCP request */
		connection = (((int) *(ncphdr + 5)) << 8) | (int) *(ncphdr + 3);
	else if (*ncphdr == 0x77 && *(ncphdr + 1) == 0x77) /* BURST packet */
		connection = (((int) *(ncphdr + 9)) << 8) | (int) *(ncphdr + 8);

	if (connection) {
		struct hlist_node *node;
		/* Now we have to look for a special NCP connection handling
		 * socket. Only these sockets have ipx_ncp_conn != 0, set by
		 * SIOCIPXNCPCONN. */
		spin_lock_bh(&intrfc->if_sklist_lock);
		sk_for_each(sk, node, &intrfc->if_sklist)
			if (ipx_sk(sk)->ipx_ncp_conn == connection) {
				sock_hold(sk);
				goto found;
			}
		sk = NULL;
	found:
		spin_unlock_bh(&intrfc->if_sklist_lock);
	}
	return sk;
}

static int ipxitf_demux_socket(struct ipx_interface *intrfc,
			       struct sk_buff *skb, int copy)
{
	struct ipxhdr *ipx = ipx_hdr(skb);
	struct sock *sock1 = NULL, *sock2 = NULL;
	struct sk_buff *skb1 = NULL, *skb2 = NULL;
	int rc;

	if (intrfc == ipx_primary_net && ntohs(ipx->ipx_dest.sock) == 0x451)
		sock1 = ncp_connection_hack(intrfc, ipx);
	if (!sock1)
		/* No special socket found, forward the packet the normal way */
		sock1 = ipxitf_find_socket(intrfc, ipx->ipx_dest.sock);

	/*
	 * We need to check if there is a primary net and if
	 * this is addressed to one of the *SPECIAL* sockets because
	 * these need to be propagated to the primary net.
	 * The *SPECIAL* socket list contains: 0x452(SAP), 0x453(RIP) and
	 * 0x456(Diagnostic).
	 */

	if (ipx_primary_net && intrfc != ipx_primary_net) {
		const int dsock = ntohs(ipx->ipx_dest.sock);

		if (dsock == 0x452 || dsock == 0x453 || dsock == 0x456)
			/* The appropriate thing to do here is to dup the
			 * packet and route to the primary net interface via
			 * ipxitf_send; however, we'll cheat and just demux it
			 * here. */
			sock2 = ipxitf_find_socket(ipx_primary_net,
							ipx->ipx_dest.sock);
	}

	/*
	 * If there is nothing to do return. The kfree will cancel any charging.
	 */
	rc = 0;
	if (!sock1 && !sock2) {
		if (!copy)
			kfree_skb(skb);
		goto out;
	}

	/*
	 * This next segment of code is a little awkward, but it sets it up
	 * so that the appropriate number of copies of the SKB are made and
	 * that skb1 and skb2 point to it (them) so that it (they) can be
	 * demuxed to sock1 and/or sock2.  If we are unable to make enough
	 * copies, we do as much as is possible.
	 */