af_ipx.c

讲述linux的初始化过程

#ifdef CONFIG_IPX_INTERN
		if(sk->protinfo.af_ipx.intrfc)
			memcpy(uaddr.sipx_node, sk->protinfo.af_ipx.intrfc->if_node,IPX_NODE_LEN);
		else
			return -ENETDOWN;		/* Someone zonked the iface */
#endif	/* CONFIG_IPX_INTERN */

		ret = ipx_bind(sock, (struct sockaddr *)&uaddr,
				sizeof(struct sockaddr_ipx));
		if(ret != 0)
			return (ret);
	}

        /* We can either connect to primary network or somewhere we can route to */
	if( !(addr->sipx_network == 0 && ipx_primary_net != NULL) && ipxrtr_lookup(addr->sipx_network) == NULL)
		return (-ENETUNREACH);

	sk->protinfo.af_ipx.dest_addr.net  = addr->sipx_network;
	sk->protinfo.af_ipx.dest_addr.sock = addr->sipx_port;
	memcpy(sk->protinfo.af_ipx.dest_addr.node,
		addr->sipx_node,IPX_NODE_LEN);
	sk->protinfo.af_ipx.type = addr->sipx_type;

	if(sock->type == SOCK_DGRAM )
	{
		sock->state 	= SS_CONNECTED;
		sk->state 	= TCP_ESTABLISHED;
	}

	return (0);
}


static int ipx_getname(struct socket *sock, struct sockaddr *uaddr,
	int *uaddr_len, int peer)
{
	ipx_address *addr;
	struct sockaddr_ipx sipx;
	struct sock *sk;

	sk = sock->sk;

	*uaddr_len = sizeof(struct sockaddr_ipx);

	if(peer)
	{
		if(sk->state != TCP_ESTABLISHED)
			return (-ENOTCONN);

		addr = &sk->protinfo.af_ipx.dest_addr;
		sipx.sipx_network = addr->net;
		memcpy(sipx.sipx_node,addr->node,IPX_NODE_LEN);
		sipx.sipx_port = addr->sock;
	}
	else
	{
		if(sk->protinfo.af_ipx.intrfc != NULL)
		{
			sipx.sipx_network=sk->protinfo.af_ipx.intrfc->if_netnum;
#ifdef CONFIG_IPX_INTERN
			memcpy(sipx.sipx_node, sk->protinfo.af_ipx.node, IPX_NODE_LEN);
#else
			memcpy(sipx.sipx_node, sk->protinfo.af_ipx.intrfc->if_node, IPX_NODE_LEN);
#endif	/* CONFIG_IPX_INTERN */

		}
		else
		{
			sipx.sipx_network = 0;
			memset(sipx.sipx_node, '\0', IPX_NODE_LEN);
		}

		sipx.sipx_port = sk->protinfo.af_ipx.port;
	}

	sipx.sipx_family = AF_IPX;
	sipx.sipx_type   = sk->protinfo.af_ipx.type;
	memcpy(uaddr,&sipx,sizeof(sipx));

	return (0);
}

int ipx_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt)
{
	/* NULL here for pt means the packet was looped back */
	ipx_interface *intrfc;
	struct ipxhdr *ipx;
	int ret;

	ipx = skb->nh.ipxh;
	
	/* Too small? */
	if(ntohs(ipx->ipx_pktsize) < sizeof(struct ipxhdr))
		goto drop;

	/* Invalid header */
	if(ntohs(ipx->ipx_pktsize) > skb->len)
		goto drop;
		
	/* Not ours */	
        if (skb->pkt_type == PACKET_OTHERHOST)
        	goto drop;
                        
	if(ipx->ipx_checksum != IPX_NO_CHECKSUM) 
	{
		if(ipx_set_checksum(ipx, ntohs(ipx->ipx_pktsize)) != ipx->ipx_checksum)
			goto drop;
	}

	/* Determine what local ipx endpoint this is */
	intrfc = ipxitf_find_using_phys(dev, pt->type);
	if(intrfc == NULL)
	{
		if(ipxcfg_auto_create_interfaces
		    && ntohl(ipx->ipx_dest.net) != 0L)
		{
			intrfc = ipxitf_auto_create(dev, pt->type);
			ipxitf_hold(intrfc);
		}

		if(intrfc == NULL)	/* Not one of ours */
			goto drop;
	}

	ret = ipxitf_rcv(intrfc, skb);
	ipxitf_put(intrfc);
	return ret;
drop:
	kfree_skb(skb);
	return (0);
}

static int ipx_sendmsg(struct socket *sock, struct msghdr *msg, int len,
	struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct sockaddr_ipx *usipx=(struct sockaddr_ipx *)msg->msg_name;
	struct sockaddr_ipx local_sipx;
	int retval;
	int flags = msg->msg_flags;

	/* Socket gets bound below anyway */
/*	if(sk->zapped)
		return (-EIO); */	/* Socket not bound */
	if(flags & ~MSG_DONTWAIT)
		return (-EINVAL);

	if(usipx)
	{
		if(sk->protinfo.af_ipx.port == 0)
		{
			struct sockaddr_ipx uaddr;
			int ret;

			uaddr.sipx_port = 0;
			uaddr.sipx_network = 0L;
#ifdef CONFIG_IPX_INTERN
			if(sk->protinfo.af_ipx.intrfc)
				memcpy(uaddr.sipx_node, sk->protinfo.af_ipx.intrfc
						->if_node,IPX_NODE_LEN);
			else
				return -ENETDOWN;               /* Someone zonked the iface */
#endif
			ret = ipx_bind(sock, (struct sockaddr *)&uaddr,
					sizeof(struct sockaddr_ipx));
			if(ret != 0)
				return (ret);
		}

		if(msg->msg_namelen < sizeof(*usipx))
			return (-EINVAL);
		if(usipx->sipx_family != AF_IPX)
			return (-EINVAL);
	}
	else
	{
		if(sk->state != TCP_ESTABLISHED)
			return (-ENOTCONN);

		usipx=&local_sipx;
		usipx->sipx_family 	= AF_IPX;
		usipx->sipx_type 	= sk->protinfo.af_ipx.type;
		usipx->sipx_port 	= sk->protinfo.af_ipx.dest_addr.sock;
		usipx->sipx_network 	= sk->protinfo.af_ipx.dest_addr.net;
		memcpy(usipx->sipx_node,sk->protinfo.af_ipx.dest_addr.node,IPX_NODE_LEN);
	}

	retval = ipxrtr_route_packet(sk, usipx, msg->msg_iov, len, flags&MSG_DONTWAIT);
	if(retval < 0)
		return (retval);

	return (len);
}


static int ipx_recvmsg(struct socket *sock, struct msghdr *msg, int size,
		int flags, struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct sockaddr_ipx *sipx = (struct sockaddr_ipx *)msg->msg_name;
	struct ipxhdr *ipx = NULL;
	struct sk_buff *skb;
	int copied, err;

	/* put the autobinding in */
	if(sk->protinfo.af_ipx.port == 0)
	{
		struct sockaddr_ipx uaddr;
		int ret;

		uaddr.sipx_port		= 0;
		uaddr.sipx_network 	= 0;

#ifdef CONFIG_IPX_INTERN
		if(sk->protinfo.af_ipx.intrfc)
			memcpy(uaddr.sipx_node, sk->protinfo.af_ipx.intrfc->if_node,IPX_NODE_LEN);
		else
			return -ENETDOWN;		/* Someone zonked the iface */
#endif	/* CONFIG_IPX_INTERN */

		ret = ipx_bind(sock, (struct sockaddr *)&uaddr,
				sizeof(struct sockaddr_ipx));
		if(ret != 0)
			return (ret);
	}
	
	if(sk->zapped)
		return (-ENOTCONN);

	skb = skb_recv_datagram(sk,flags&~MSG_DONTWAIT,flags&MSG_DONTWAIT,&err);
	if(!skb)
		goto out;

	ipx 	= skb->nh.ipxh;
	copied 	= ntohs(ipx->ipx_pktsize) - sizeof(struct ipxhdr);
	if(copied > size)
	{
		copied=size;
		msg->msg_flags |= MSG_TRUNC;
	}

	err = skb_copy_datagram_iovec(skb, sizeof(struct ipxhdr), msg->msg_iov,
					copied);
	if(err)
		goto out_free;
	sk->stamp = skb->stamp;

	msg->msg_namelen = sizeof(*sipx);

	if(sipx)
	{
		sipx->sipx_family	= AF_IPX;
		sipx->sipx_port		= ipx->ipx_source.sock;
		memcpy(sipx->sipx_node,ipx->ipx_source.node,IPX_NODE_LEN);
		sipx->sipx_network	= ipx->ipx_source.net;
		sipx->sipx_type 	= ipx->ipx_type;
	}
	err = copied;

out_free:
	skb_free_datagram(sk, skb);
out:
	return (err);
}


static int ipx_ioctl(struct socket *sock,unsigned int cmd, unsigned long arg)
{
	long amount = 0;
	struct sock *sk = sock->sk;

	switch(cmd)
	{
		case TIOCOUTQ:
			amount = sk->sndbuf - atomic_read(&sk->wmem_alloc);
			if(amount < 0)
				amount = 0;
			return (put_user(amount, (int *)arg));

		case TIOCINQ:
		{
			struct sk_buff *skb;
			/* These two are safe on a single CPU system as only user tasks fiddle here */
			if((skb = skb_peek(&sk->receive_queue)) != NULL)
				amount = skb->len - sizeof(struct ipxhdr);
			return (put_user(amount, (int *)arg));
		}

		case SIOCADDRT:
		case SIOCDELRT:
			if(!capable(CAP_NET_ADMIN))
				return (-EPERM);
			return (ipxrtr_ioctl(cmd,(void *)arg));

		case SIOCSIFADDR:
		case SIOCAIPXITFCRT:
		case SIOCAIPXPRISLT:
			if(!capable(CAP_NET_ADMIN))
				return (-EPERM);

		case SIOCGIFADDR:
			return (ipxitf_ioctl(cmd,(void *)arg));

		case SIOCIPXCFGDATA:
			return (ipxcfg_get_config_data((void *)arg));

		case SIOCIPXNCPCONN:
                {
			/*
			 * This socket wants to take care of the NCP connection
			 * handed to us in arg.
			 */
                	if (!capable(CAP_NET_ADMIN))
                		return(-EPERM);
			return get_user(sk->protinfo.af_ipx.ipx_ncp_conn, (const unsigned short *)(arg));
                }

		case SIOCGSTAMP:
		{
			int ret = -EINVAL;
			if(sk)
			{
				if(sk->stamp.tv_sec == 0)
					return (-ENOENT);
				ret = -EFAULT;
				if(!copy_to_user((void *)arg, &sk->stamp,
						sizeof(struct timeval)))
					ret = 0;
			}

			return (ret);
		}

		case SIOCGIFDSTADDR:
		case SIOCSIFDSTADDR:
		case SIOCGIFBRDADDR:
		case SIOCSIFBRDADDR:
		case SIOCGIFNETMASK:
		case SIOCSIFNETMASK:
			return (-EINVAL);

		default:
			return (dev_ioctl(cmd,(void *) arg));
	}

	/*NOT REACHED*/
	return (0);
}

/*
 *      SPX interface support
 */

int ipx_register_spx(struct proto_ops **p, struct net_proto_family *spx)
{
        if(spx_family_ops!=NULL)
                return -EBUSY;
        cli();
        MOD_INC_USE_COUNT;
        *p=&ipx_dgram_ops;
        spx_family_ops=spx;
        sti();
        return 0;
}

int ipx_unregister_spx(void)
{
        spx_family_ops=NULL;
        MOD_DEC_USE_COUNT;
        return 0;
}

/*
 * Socket family declarations
 */

static struct net_proto_family ipx_family_ops = {
	PF_IPX,
	ipx_create
};

static struct proto_ops SOCKOPS_WRAPPED(ipx_dgram_ops) = {
	family:		PF_IPX,

	release:	ipx_release,
	bind:		ipx_bind,
	connect:	ipx_connect,
	socketpair:	sock_no_socketpair,
	accept:		sock_no_accept,
	getname:	ipx_getname,
	poll:		datagram_poll,
	ioctl:		ipx_ioctl,
	listen:		sock_no_listen,
	shutdown:	sock_no_shutdown, /* FIXME: We have to really support shutdown. */
	setsockopt:	ipx_setsockopt,
	getsockopt:	ipx_getsockopt,
	sendmsg:	ipx_sendmsg,
	recvmsg:	ipx_recvmsg,
	mmap:		sock_no_mmap,
};

#include <linux/smp_lock.h>
SOCKOPS_WRAP(ipx_dgram, PF_IPX);

static struct packet_type ipx_8023_packet_type =

{
	__constant_htons(ETH_P_802_3),
	NULL,		/* All devices */
	ipx_rcv,
	NULL,
	NULL,
};

static struct packet_type ipx_dix_packet_type =
{
	__constant_htons(ETH_P_IPX),
	NULL,		/* All devices */
	ipx_rcv,
	NULL,
	NULL,
};

static struct notifier_block ipx_dev_notifier={
	ipxitf_device_event,
	NULL,
	0
};


extern struct datalink_proto *make_EII_client(void);
extern struct datalink_proto *make_8023_client(void);
extern void destroy_EII_client(struct datalink_proto *);
extern void destroy_8023_client(struct datalink_proto *);

static unsigned char ipx_8022_type = 0xE0;
static unsigned char ipx_snap_id[5] = { 0x0, 0x0, 0x0, 0x81, 0x37 };




static int __init ipx_init(void)
{
	(void) sock_register(&ipx_family_ops);

	pEII_datalink = make_EII_client();
	dev_add_pack(&ipx_dix_packet_type);

	p8023_datalink = make_8023_client();
	dev_add_pack(&ipx_8023_packet_type);

	if((p8022_datalink = register_8022_client(ipx_8022_type,ipx_rcv)) == NULL)
		printk(KERN_CRIT "IPX: Unable to register with 802.2\n");

	if((pSNAP_datalink = register_snap_client(ipx_snap_id,ipx_rcv)) == NULL)
		printk(KERN_CRIT "IPX: Unable to register with SNAP\n");

	register_netdevice_notifier(&ipx_dev_notifier);

#ifdef CONFIG_PROC_FS
	proc_net_create("ipx", 0, ipx_get_info);
	proc_net_create("ipx_interface", 0, ipx_interface_get_info);
	proc_net_create("ipx_route", 0, ipx_rt_get_info);
#endif

	printk(KERN_INFO "NET4: Linux IPX 0.42v4 for NET4.0\n");
	printk(KERN_INFO "IPX Portions Copyright (c) 1995 Caldera, Inc.\n");
	printk(KERN_INFO "IPX Portions Copyright (c) 2000 Conectiva, Inc.\n");
	return 0;
}
module_init(ipx_init);

/* Higher layers need this info to prep tx pkts */
int ipx_if_offset(unsigned long ipx_net_number)
{
	ipx_route *rt = NULL;

	rt = ipxrtr_lookup(ipx_net_number);

	return (rt ? rt->ir_intrfc->if_ipx_offset : -ENETUNREACH);
}

/* Export symbols for higher layers */
EXPORT_SYMBOL(ipxrtr_route_skb);
EXPORT_SYMBOL(ipx_if_offset);
EXPORT_SYMBOL(ipx_remove_socket);
EXPORT_SYMBOL(ipx_register_spx);
EXPORT_SYMBOL(ipx_unregister_spx);

/* Note on MOD_{INC,DEC}_USE_COUNT:
 *
 * Use counts are incremented/decremented when
 * sockets are created/deleted.
 *
 * Routes are always associated with an interface, and
 * allocs/frees will remain properly accounted for by
 * their associated interfaces.
 *
 * Ergo, before the ipx module can be removed, all IPX
 * sockets be closed from user space.
 */

#ifdef MODULE
static void ipx_proto_finito(void)
{
	/* no need to worry about having anything on the ipx_interfaces
	 * list, when a interface is created we increment the module
	 * usage count, so the module will only be unloaded when there
	 * are no more interfaces */

	proc_net_remove("ipx_route");
	proc_net_remove("ipx_interface");
	proc_net_remove("ipx");

	unregister_netdevice_notifier(&ipx_dev_notifier);

	unregister_snap_client(ipx_snap_id);
	pSNAP_datalink 	= NULL;

	unregister_8022_client(ipx_8022_type);
	p8022_datalink 	= NULL;

	dev_remove_pack(&ipx_8023_packet_type);
	destroy_8023_client(p8023_datalink);
	p8023_datalink 	= NULL;

	dev_remove_pack(&ipx_dix_packet_type);
	destroy_EII_client(pEII_datalink);
	pEII_datalink 	= NULL;

	(void) sock_unregister(ipx_family_ops.family);

	return;
}
module_exit(ipx_proto_finito);
#endif /* MODULE */

#endif /* CONFIG_IPX || CONFIG_IPX_MODULE */