ddp.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

/*
 *	DDP:	An implementation of the AppleTalk DDP protocol for
 *		Ethernet 'ELAP'.
 *
 *		Alan Cox  <[e-mail]>
 *
 *		With more than a little assistance from
 *
 *		Wesley Craig <[e-mail]>
 *
 *	Fixes:
 *		Michael Callahan	:	Made routing work
 *		Wesley Craig		:	Fix probing to listen to a
 *						passed node id.
 *		Alan Cox		:	Added send/recvmsg support
 *		Alan Cox		:	Moved at. to protinfo in
 *						socket.
 *		Alan Cox		:	Added firewall hooks.
 *		Alan Cox		:	Supports new ARPHRD_LOOPBACK
 *		Christer Weinigel	: 	Routing and /proc fixes.
 *		Bradford Johnson	:	LocalTalk.
 *		Tom Dyas		:	Module support.
 *		Alan Cox		:	Hooks for PPP (based on the
 *						LocalTalk hook).
 *		Alan Cox		:	Posix bits
 *		Alan Cox/Mike Freeman	:	Possible fix to NBP problems
 *		Bradford Johnson	:	IP-over-DDP (experimental)
 *		Jay Schulist		:	Moved IP-over-DDP to its own
 *						driver file. (ipddp.c & ipddp.h)
 *		Jay Schulist		:	Made work as module with 
 *						AppleTalk drivers, cleaned it.
 *		Rob Newberry		:	Added proxy AARP and AARP
 *						procfs, moved probing to AARP
 *						module.
 *              Adrian Sun/ 
 *              Michael Zuelsdorff      :       fix for net.0 packets. don't 
 *                                              allow illegal ether/tokentalk
 *                                              port assignment. we lose a 
 *                                              valid localtalk port as a 
 *                                              result.
 *		Arnaldo C. de Melo	:	Cleanup, in preparation for
 *						shared skb support 8)
 *
 *		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.
 * 
 */

#include <linux/config.h>
#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/route.h>
#include <linux/inet.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/termios.h>	/* For TIOCOUTQ/INQ */
#include <net/datalink.h>
#include <net/p8022.h>
#include <net/psnap.h>
#include <net/sock.h>
#include <linux/ip.h>
#include <net/route.h>
#include <linux/atalk.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>

#ifdef CONFIG_PROC_FS
extern void aarp_register_proc_fs(void);
extern void aarp_unregister_proc_fs(void);
#endif

extern void aarp_cleanup_module(void);

extern void aarp_probe_network(struct atalk_iface *atif);
extern int  aarp_proxy_probe_network(struct atalk_iface *atif,
					struct at_addr *sa);
extern void aarp_proxy_remove(struct net_device *dev, struct at_addr *sa);

#undef APPLETALK_DEBUG
#ifdef APPLETALK_DEBUG
#define DPRINT(x)		print(x)
#else
#define DPRINT(x)
#endif /* APPLETALK_DEBUG */

#ifdef CONFIG_SYSCTL
extern inline void atalk_register_sysctl(void);
extern inline void atalk_unregister_sysctl(void);
#endif /* CONFIG_SYSCTL */

struct datalink_proto *ddp_dl, *aarp_dl;
static struct proto_ops atalk_dgram_ops;

/**************************************************************************\
*                                                                          *
* Handlers for the socket list.                                            *
*                                                                          *
\**************************************************************************/

static struct sock *atalk_sockets;
static spinlock_t atalk_sockets_lock = SPIN_LOCK_UNLOCKED;

extern inline void atalk_insert_socket(struct sock *sk)
{
	spin_lock_bh(&atalk_sockets_lock);
	sk->next = atalk_sockets;
	if (sk->next)
		atalk_sockets->pprev = &sk->next;
	atalk_sockets = sk;
	sk->pprev = &atalk_sockets;
	spin_unlock_bh(&atalk_sockets_lock);
}

extern inline void atalk_remove_socket(struct sock *sk)
{
	spin_lock_bh(&atalk_sockets_lock);
	if (sk->pprev) {
		if (sk->next)
			sk->next->pprev = sk->pprev;
		*sk->pprev = sk->next;
		sk->pprev = NULL;
	}
	spin_unlock_bh(&atalk_sockets_lock);
}

static struct sock *atalk_search_socket(struct sockaddr_at *to,
					struct atalk_iface *atif)
{
	struct sock *s;

	spin_lock_bh(&atalk_sockets_lock);
	for (s = atalk_sockets; s; s = s->next) {
		if (to->sat_port != s->protinfo.af_at.src_port)
			continue;

	    	if (to->sat_addr.s_net == ATADDR_ANYNET &&
		    to->sat_addr.s_node == ATADDR_BCAST &&
		    s->protinfo.af_at.src_net == atif->address.s_net)
			break;

	    	if (to->sat_addr.s_net == s->protinfo.af_at.src_net &&
		    (to->sat_addr.s_node == s->protinfo.af_at.src_node ||
		     to->sat_addr.s_node == ATADDR_BCAST ||
		     to->sat_addr.s_node == ATADDR_ANYNODE))
			break;

	    	/* XXXX.0 -- we got a request for this router. make sure
		 * that the node is appropriately set. */
		if (to->sat_addr.s_node == ATADDR_ANYNODE &&
		    to->sat_addr.s_net != ATADDR_ANYNET &&
		    atif->address.s_node == s->protinfo.af_at.src_node) {
			to->sat_addr.s_node = atif->address.s_node;
			break; 
		}
	}
	spin_unlock_bh(&atalk_sockets_lock);
	return s;
}

/*
 * Try to find a socket matching ADDR in the socket list,
 * if found then return it.  If not, insert SK into the
 * socket list.
 *
 * This entire operation must execute atomically.
 */
static struct sock *atalk_find_or_insert_socket(struct sock *sk,
						struct sockaddr_at *sat)
{
	struct sock *s;

	spin_lock_bh(&atalk_sockets_lock);
	for (s = atalk_sockets; s; s = s->next)
		if (s->protinfo.af_at.src_net == sat->sat_addr.s_net &&
		    s->protinfo.af_at.src_node == sat->sat_addr.s_node &&
		    s->protinfo.af_at.src_port == sat->sat_port)
			break;

	if (!s) {
		/* Wheee, it's free, assign and insert. */
		sk->next = atalk_sockets;
		if (sk->next)
			atalk_sockets->pprev = &sk->next;
		atalk_sockets = sk;
		sk->pprev = &atalk_sockets;
	}

	spin_unlock_bh(&atalk_sockets_lock);
	return s;
}

static void atalk_destroy_timer(unsigned long data)
{
	struct sock *sk = (struct sock *) data;

	if (!atomic_read(&sk->wmem_alloc) &&
	    !atomic_read(&sk->rmem_alloc) && sk->dead) {
		sock_put(sk);
		MOD_DEC_USE_COUNT;
	} else {
		sk->timer.expires = jiffies + SOCK_DESTROY_TIME;
		add_timer(&sk->timer);
	}
}

extern inline void atalk_destroy_socket(struct sock *sk)
{
	atalk_remove_socket(sk);
	skb_queue_purge(&sk->receive_queue);

	if (!atomic_read(&sk->wmem_alloc) &&
	    !atomic_read(&sk->rmem_alloc) && sk->dead) {
		sock_put(sk);
		MOD_DEC_USE_COUNT;
	} else {
		init_timer(&sk->timer);
		sk->timer.expires = jiffies + SOCK_DESTROY_TIME;
		sk->timer.function = atalk_destroy_timer;
		sk->timer.data = (unsigned long) sk;
		add_timer(&sk->timer);
	}
}

/* Called from proc fs */
static int atalk_get_info(char *buffer, char **start, off_t offset, int length)
{
	off_t pos = 0;
	off_t begin = 0;
	int len = sprintf(buffer, "Type local_addr  remote_addr tx_queue "
				  "rx_queue st uid\n");
	struct sock *s;
	/* Output the AppleTalk data for the /proc filesystem */

	spin_lock_bh(&atalk_sockets_lock);
	for (s = atalk_sockets; s; s = s->next) {
		len += sprintf(buffer + len,"%02X   ", s->type);
		len += sprintf(buffer + len,"%04X:%02X:%02X  ",
			       ntohs(s->protinfo.af_at.src_net),
			       s->protinfo.af_at.src_node,
			       s->protinfo.af_at.src_port);
		len += sprintf(buffer + len,"%04X:%02X:%02X  ",
			       ntohs(s->protinfo.af_at.dest_net),
			       s->protinfo.af_at.dest_node,
			       s->protinfo.af_at.dest_port);
		len += sprintf(buffer + len,"%08X:%08X ",
			       atomic_read(&s->wmem_alloc),
			       atomic_read(&s->rmem_alloc));
		len += sprintf(buffer + len,"%02X %d\n", s->state, 
			       SOCK_INODE(s->socket)->i_uid);

		/* Are we still dumping unwanted data then discard the record */
		pos = begin + len;

		if (pos < offset) {
			len = 0;	/* Keep dumping into the buffer start */
			begin = pos;
		}
		if (pos > offset + length)	/* We have dumped enough */
			break;
	}
	spin_unlock_bh(&atalk_sockets_lock);

	/* The data in question runs from begin to begin+len */
	*start = buffer + offset - begin;	/* Start of wanted data */
	len -= offset - begin;   /* Remove unwanted header data from length */
	if (len > length)
		len = length;	   /* Remove unwanted tail data from length */

	return len;
}

/**************************************************************************\
*                                                                          *
* Routing tables for the AppleTalk socket layer.                           *
*                                                                          *
\**************************************************************************/

/* Anti-deadlock ordering is router_lock --> iface_lock -DaveM */
static struct atalk_route *atalk_router_list;
static rwlock_t atalk_router_lock = RW_LOCK_UNLOCKED;

static struct atalk_iface *atalk_iface_list;
static spinlock_t atalk_iface_lock = SPIN_LOCK_UNLOCKED;

/* For probing devices or in a routerless network */
static struct atalk_route atrtr_default;

/* AppleTalk interface control */
/*
 * Drop a device. Doesn't drop any of its routes - that is the caller's
 * problem. Called when we down the interface or delete the address.
 */
static void atif_drop_device(struct net_device *dev)
{
	struct atalk_iface **iface = &atalk_iface_list;
	struct atalk_iface *tmp;

	spin_lock_bh(&atalk_iface_lock);
	while ((tmp = *iface) != NULL) {
		if (tmp->dev == dev) {
			*iface = tmp->next;
			kfree(tmp);
			dev->atalk_ptr = NULL;
			MOD_DEC_USE_COUNT;
		} else
			iface = &tmp->next;
	}
	spin_unlock_bh(&atalk_iface_lock);
}

static struct atalk_iface *atif_add_device(struct net_device *dev,
					   struct at_addr *sa)
{
	struct atalk_iface *iface = kmalloc(sizeof(*iface), GFP_KERNEL);

	if (!iface)
		return NULL;

	iface->dev = dev;
	dev->atalk_ptr = iface;
	iface->address = *sa;
	iface->status = 0;

	spin_lock_bh(&atalk_iface_lock);
	iface->next = atalk_iface_list;
	atalk_iface_list = iface;
	spin_unlock_bh(&atalk_iface_lock);

	MOD_INC_USE_COUNT;
	return iface;
}

/* Perform phase 2 AARP probing on our tentative address */
static int atif_probe_device(struct atalk_iface *atif)
{
	int netrange = ntohs(atif->nets.nr_lastnet) -
			ntohs(atif->nets.nr_firstnet) + 1;
	int probe_net = ntohs(atif->address.s_net);
	int probe_node = atif->address.s_node;
	int netct, nodect;

	/* Offset the network we start probing with */
	if (probe_net == ATADDR_ANYNET) {
		probe_net = ntohs(atif->nets.nr_firstnet);
		if (netrange)
			probe_net += jiffies % netrange;
	}
	if (probe_node == ATADDR_ANYNODE)
		probe_node = jiffies & 0xFF;

	/* Scan the networks */
	atif->status |= ATIF_PROBE;
	for (netct = 0; netct <= netrange; netct++) {
		/* Sweep the available nodes from a given start */
		atif->address.s_net = htons(probe_net);
		for (nodect = 0; nodect < 256; nodect++) {
			atif->address.s_node = ((nodect+probe_node) & 0xFF);
			if (atif->address.s_node > 0 &&
			    atif->address.s_node < 254) {
				/* Probe a proposed address */
				aarp_probe_network(atif);

				if (!(atif->status & ATIF_PROBE_FAIL)) {
					atif->status &= ~ATIF_PROBE;
					return 0;
				}
			}
			atif->status &= ~ATIF_PROBE_FAIL;
		}
		probe_net++;
		if (probe_net > ntohs(atif->nets.nr_lastnet))
			probe_net = ntohs(atif->nets.nr_firstnet);
	}
	atif->status &= ~ATIF_PROBE;

	return -EADDRINUSE;	/* Network is full... */
}


/* Perform AARP probing for a proxy address */
static int atif_proxy_probe_device(struct atalk_iface *atif,
				   struct at_addr* proxy_addr)
{
	int netrange = ntohs(atif->nets.nr_lastnet) -
			ntohs(atif->nets.nr_firstnet) + 1;
	/* we probe the interface's network */
	int probe_net = ntohs(atif->address.s_net);
	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
	int netct, nodect;

	/* Offset the network we start probing with */
	if (probe_net == ATADDR_ANYNET) {
		probe_net = ntohs(atif->nets.nr_firstnet);
		if (netrange)
			probe_net += jiffies % netrange;
	}

	if (probe_node == ATADDR_ANYNODE)
		probe_node = jiffies & 0xFF;
		
	/* Scan the networks */
	for (netct = 0; netct <= netrange; netct++) {
		/* Sweep the available nodes from a given start */
		proxy_addr->s_net = htons(probe_net);
		for (nodect = 0; nodect < 256; nodect++) {
			proxy_addr->s_node = ((nodect + probe_node) & 0xFF);
			if (proxy_addr->s_node > 0 &&
			    proxy_addr->s_node < 254) {
				/* Tell AARP to probe a proposed address */
				int ret = aarp_proxy_probe_network(atif,
								    proxy_addr);

				if (ret != -EADDRINUSE)
					return ret;
			}
		}
		probe_net++;
		if (probe_net > ntohs(atif->nets.nr_lastnet))
			probe_net = ntohs(atif->nets.nr_firstnet);
	}

	return -EADDRINUSE;	/* Network is full... */
}


struct at_addr *atalk_find_dev_addr(struct net_device *dev)
{
	struct atalk_iface *iface = dev->atalk_ptr;
	return iface ? &iface->address : NULL;
}

static struct at_addr *atalk_find_primary(void)
{
	struct atalk_iface *fiface = NULL;
	struct at_addr *retval;
	struct atalk_iface *iface;

	/*
	 * Return a point-to-point interface only if
	 * there is no non-ptp interface available.
	 */
	spin_lock_bh(&atalk_iface_lock);
	for (iface = atalk_iface_list; iface; iface = iface->next) {
		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
			fiface = iface;
		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
			retval = &iface->address;
			goto out;
		}
	}

	if (fiface)
		retval = &fiface->address;
	else if (atalk_iface_list)
		retval = &atalk_iface_list->address;
	else
		retval = NULL;
out:	spin_unlock_bh(&atalk_iface_lock);
	return retval;
}

/*
 * Find a match for 'any network' - ie any of our interfaces with that
 * node number will do just nicely.
 */
static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
{
	struct atalk_iface *iface = dev->atalk_ptr;

	if (!iface || iface->status & ATIF_PROBE)
		return NULL;

	if (node == ATADDR_BCAST ||
	    iface->address.s_node == node ||
	    node == ATADDR_ANYNODE)
		return iface;

	return NULL;
}

/* Find a match for a specific network:node pair */
static struct atalk_iface *atalk_find_interface(int net, int node)
{
	struct atalk_iface *iface;