patch-2.1.68 linux/net/packet/af_packet.c

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diff -u --recursive --new-file v2.1.67/linux/net/packet/af_packet.c linux/net/packet/af_packet.c
@@ -0,0 +1,1251 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		PACKET - implements raw packet sockets.
+ *
+ *		Doesn't belong in IP but it's currently too hooked into ip
+ *		to separate.
+ *
+ * Version:	@(#)packet.c	1.0.6	05/25/93
+ *
+ * Authors:	Ross Biro, <bir7@leland.Stanford.Edu>
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *		Alan Cox, <gw4pts@gw4pts.ampr.org>
+ *
+ * Fixes:	
+ *		Alan Cox	:	verify_area() now used correctly
+ *		Alan Cox	:	new skbuff lists, look ma no backlogs!
+ *		Alan Cox	:	tidied skbuff lists.
+ *		Alan Cox	:	Now uses generic datagram routines I
+ *					added. Also fixed the peek/read crash
+ *					from all old Linux datagram code.
+ *		Alan Cox	:	Uses the improved datagram code.
+ *		Alan Cox	:	Added NULL's for socket options.
+ *		Alan Cox	:	Re-commented the code.
+ *		Alan Cox	:	Use new kernel side addressing
+ *		Rob Janssen	:	Correct MTU usage.
+ *		Dave Platt	:	Counter leaks caused by incorrect
+ *					interrupt locking and some slightly
+ *					dubious gcc output. Can you read
+ *					compiler: it said _VOLATILE_
+ *	Richard Kooijman	:	Timestamp fixes.
+ *		Alan Cox	:	New buffers. Use sk->mac.raw.
+ *		Alan Cox	:	sendmsg/recvmsg support.
+ *		Alan Cox	:	Protocol setting support
+ *	Alexey Kuznetsov	:	Untied from IPv4 stack.
+ *
+ *		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>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/fcntl.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_packet.h>
+#include <linux/wireless.h>
+#include <linux/kerneld.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#if defined(CONFIG_DLCI) || defined(CONFIG_DLCI_MODULE)
+#include <linux/if_frad.h>
+#endif
+
+/*
+   Old SOCK_PACKET. Do exist programs, which use it?
+   (not counting tcpdump) - lots of them yes - AC. 
+   
+ */
+#define CONFIG_SOCK_PACKET	1
+
+/*
+   Proposed replacement for SIOC{ADD,DEL}MULTI and
+   IFF_PROMISC, IFF_ALLMULTI flags.
+
+   It is more expensive, but I believe,
+   it is really correct solution: reentereble, safe and fault tolerant.
+
+   Differences:
+   - Changing IFF_ALLMULTI from user level is disabled.
+     It could only confused multicast routing daemons, not more.
+   - IFF_PROMISC is faked by keeping reference count and
+     global flag, so that real IFF_PROMISC == (gflag|(count != 0))
+     I'd remove it too, but it would require recompilation tcpdump
+     and another applications, using promiscuous mode.
+   - SIOC{ADD/DEL}MULTI are moved to deprecated state,
+     they work, but complain. I do know who uses them.
+     
+ 
+*************FIXME***************
+  Alexey : This doesnt cook Im afraid. We need the low level SIOCADD/DELMULTI
+  and also IFF_ALLMULTI for DECNET, Appletalk and other stuff as well as
+  BSD compatibility issues.
+  
+ */
+#define CONFIG_PACKET_MULTICAST	1
+
+/*
+   Assumptions:
+   - if device has no dev->hard_header routine, it adds and removes ll header
+     inside itself. In this case ll header is invisible outside of device,
+     but higher levels still should reserve dev->hard_header_len.
+     Some devices are enough clever to reallocate skb, when header
+     will not fit to reserved space (tunnel), another ones are silly
+     (PPP).
+   - packet socket receives packets with pulled ll header,
+     so that SOCK_RAW should push it back.
+
+On receive:
+-----------
+
+Incoming, dev->hard_header!=NULL
+   mac.raw -> ll header
+   data    -> data
+
+Outgoing, dev->hard_header!=NULL
+   mac.raw -> ll header
+   data    -> ll header
+
+Incoming, dev->hard_header==NULL
+   mac.raw -> UNKNOWN position. It is very likely, that it points to ll header.
+              PPP makes it, that is wrong, because introduce assymetry
+	      between rx and tx paths.
+   data    -> data
+
+Outgoing, dev->hard_header==NULL
+   mac.raw -> data. ll header is still not built!
+   data    -> data
+
+Resume
+  If dev->hard_header==NULL we are unlikely to restore sensible ll header.
+
+
+On transmit:
+------------
+
+dev->hard_header != NULL
+   mac.raw -> ll header
+   data    -> ll header
+
+dev->hard_header == NULL (ll header is added by device, we cannot control it)
+   mac.raw -> data
+   data -> data
+
+   We should set nh.raw on output to correct posistion,
+   packet classifier depends on it.
+ */
+
+/* List of all packet sockets. */
+struct sock * packet_sklist = NULL;
+
+/* Private packet socket structures. */
+
+#ifdef CONFIG_PACKET_MULTICAST
+struct packet_mclist
+{
+	struct packet_mclist	*next;
+	int			ifindex;
+	int			count;
+	unsigned short		type;
+	unsigned short		alen;
+	unsigned char		addr[8];
+};
+#endif
+
+static void packet_flush_mclist(struct sock *sk);
+
+struct packet_opt
+{
+	struct packet_type	prot_hook;
+	char			running;	/* prot_hook is attached*/
+	int			ifindex;	/* bound device		*/
+#ifdef CONFIG_PACKET_MULTICAST
+	struct packet_mclist	*mclist;
+#endif
+};
+
+extern struct proto_ops packet_ops;
+
+#ifdef CONFIG_SOCK_PACKET
+extern struct proto_ops packet_ops_spkt;
+
+static int packet_rcv_spkt(struct sk_buff *skb, struct device *dev,  struct packet_type *pt)
+{
+	struct sock *sk;
+	struct sockaddr_pkt *spkt = (struct sockaddr_pkt*)skb->cb;
+
+	/*
+	 *	When we registered the protocol we saved the socket in the data
+	 *	field for just this event.
+	 */
+
+	sk = (struct sock *) pt->data;
+	
+	/*
+	 *	Yank back the headers [hope the device set this
+	 *	right or kerboom...]
+	 *
+	 *	Incoming packets have ll header pulled,
+	 *	push it back.
+	 *
+	 *	For outgoing ones skb->data == skb->mac.raw
+	 *	so that this procedure is noop.
+	 */
+
+	skb_push(skb, skb->data-skb->mac.raw);
+
+	/*
+	 *	The SOCK_PACKET socket receives _all_ frames.
+	 */
+
+	spkt->spkt_family = dev->type;
+	strncpy(spkt->spkt_device, dev->name, 15);
+	spkt->spkt_protocol = skb->protocol;
+
+	/*
+	 *	Charge the memory to the socket. This is done specifically
+	 *	to prevent sockets using all the memory up.
+	 */
+
+	if (sock_queue_rcv_skb(sk,skb)<0)
+	{
+		kfree_skb(skb, FREE_READ);
+		return 0;
+	}
+
+	/*
+	 *	Processing complete.
+	 */
+	return(0);
+}
+
+
+/*
+ *	Output a raw packet to a device layer. This bypasses all the other
+ *	protocol layers and you must therefore supply it with a complete frame
+ */
+ 
+static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg, int len,
+			       struct scm_cookie *scm)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	struct device *dev;
+	struct sockaddr_pkt *saddr=(struct sockaddr_pkt *)msg->msg_name;
+	unsigned short proto=0;
+	int err;
+	
+	/*
+	 *	Check the flags. 
+	 */
+
+	if (msg->msg_flags&~MSG_DONTWAIT)
+		return(-EINVAL);
+
+	/*
+	 *	Get and verify the address. 
+	 */
+
+	if (saddr)
+	{
+		if (msg->msg_namelen < sizeof(struct sockaddr))
+			return(-EINVAL);
+		if (msg->msg_namelen==sizeof(struct sockaddr_pkt))
+			proto=saddr->spkt_protocol;
+	}
+	else
+		return(-ENOTCONN);	/* SOCK_PACKET must be sent giving an address */
+
+	/*
+	 *	Find the device first to size check it 
+	 */
+
+	saddr->spkt_device[13] = 0;
+	dev = dev_get(saddr->spkt_device);
+	if (dev == NULL) 
+	{
+		return(-ENODEV);
+  	}
+	
+	/*
+	 *	You may not queue a frame bigger than the mtu. This is the lowest level
+	 *	raw protocol and you must do your own fragmentation at this level.
+	 */
+	 
+	if(len>dev->mtu+dev->hard_header_len)
+  		return -EMSGSIZE;
+
+	dev_lock_list();
+	skb = sock_wmalloc(sk, len+dev->hard_header_len+15, 0, GFP_KERNEL);
+
+	/*
+	 *	If the write buffer is full, then tough. At this level the user gets to
+	 *	deal with the problem - do your own algorithmic backoffs. That's far
+	 *	more flexible.
+	 */
+	 
+	if (skb == NULL) 
+	{
+		dev_unlock_list();
+		return(-ENOBUFS);
+	}
+	
+	/*
+	 *	Fill it in 
+	 */
+	 
+	/* FIXME: Save some space for broken drivers that write a
+	 * hard header at transmission time by themselves. PPP is the
+	 * notable one here. This should really be fixed at the driver level.
+	 */
+	skb_reserve(skb,(dev->hard_header_len+15)&~15);
+	skb->mac.raw = skb->nh.raw = skb->data;
+
+	/* Try to align data part correctly */
+	if (dev->hard_header) {
+		skb->data -= dev->hard_header_len;
+		skb->tail -= dev->hard_header_len;
+		skb->mac.raw = skb->data;
+	}
+	err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
+	skb->arp = 1;	/* No ARP needs doing on this (complete) frame */
+	skb->protocol = proto;
+	skb->dev = dev;
+	skb->priority = sk->priority;
+	dev_unlock_list();
+
+	/*
+	 *	Now send it
+	 */
+
+	if (err)
+	{
+		err = -EFAULT;
+	}
+	else
+	{
+		if (!(dev->flags & IFF_UP))
+		{
+			err = -ENETDOWN;
+		}
+	}
+
+	if (err) 
+	{
+		kfree_skb(skb, FREE_WRITE);
+		return err;
+	}
+
+	dev_queue_xmit(skb);
+	return(len);
+}
+#endif
+
+static int packet_rcv(struct sk_buff *skb, struct device *dev,  struct packet_type *pt)
+{
+	struct sock *sk;
+	struct sockaddr_ll *sll = (struct sockaddr_ll*)skb->cb;
+	
+	/*
+	 *	When we registered the protocol we saved the socket in the data
+	 *	field for just this event.
+	 */
+
+	sk = (struct sock *) pt->data;
+
+	/*
+	 *	The SOCK_PACKET socket receives _all_ frames.
+	 */
+
+	skb->dev = dev;
+
+	sll->sll_family = AF_PACKET;
+	sll->sll_hatype = dev->type;
+	sll->sll_protocol = skb->protocol;
+	sll->sll_pkttype = skb->pkt_type;
+	sll->sll_ifindex = dev->ifindex;
+	sll->sll_halen = 0;
+
+	if (dev->hard_header_parse)
+		sll->sll_halen = dev->hard_header_parse(skb, sll->sll_addr);
+
+	if (dev->hard_header) {
+		/* The device has an explicit notion of ll header,
+		   exported to higher levels.
+
+		   Otherwise, the device hides datails of it frame
+		   structure, so that corresponding packet head
+		   never delivered to user.
+		 */
+		if (sk->type != SOCK_DGRAM)
+			skb_push(skb, skb->data - skb->mac.raw);
+		else if (skb->pkt_type == PACKET_OUTGOING) {
+			/* Special case: outgoing packets have ll header at head */
+			skb_pull(skb, skb->nh.raw - skb->data);
+		}
+	}
+
+	/*
+	 *	Charge the memory to the socket. This is done specifically
+	 *	to prevent sockets using all the memory up.
+	 */
+
+	if (sock_queue_rcv_skb(sk,skb)<0)
+	{
+		kfree_skb(skb, FREE_READ);
+		return 0;
+	}
+	return(0);
+}
+
+static int packet_sendmsg(struct socket *sock, struct msghdr *msg, int len,
+			  struct scm_cookie *scm)
+{
+	struct sock *sk = sock->sk;
+	struct sk_buff *skb;
+	struct device *dev;
+	struct sockaddr_ll *saddr=(struct sockaddr_ll *)msg->msg_name;
+	unsigned short proto;
+	int ifindex;
+	int err;
+	int reserve = 0;
+	
+	/*
+	 *	Check the flags. 
+	 */
+
+	if (msg->msg_flags&~MSG_DONTWAIT) 
+		return(-EINVAL);
+
+	/*
+	 *	Get and verify the address. 
+	 */
+	 
+	if (saddr == NULL) {
+		ifindex = sk->protinfo.af_packet->ifindex;
+		proto = sk->num;
+	} else {
+		if (msg->msg_namelen < sizeof(struct sockaddr_ll)) 
+			return -EINVAL;
+		ifindex = saddr->sll_ifindex;
+		proto = saddr->sll_protocol;
+	}
+
+	dev = dev_get_by_index(ifindex);
+	if (dev == NULL)
+		return -ENXIO;
+	if (sock->type == SOCK_RAW)
+		reserve = dev->hard_header_len;
+
+	if (len > dev->mtu+reserve)
+  		return -EMSGSIZE;
+
+	dev_lock_list();
+
+	skb = sock_alloc_send_skb(sk, len+dev->hard_header_len+15, 0, msg->msg_flags&MSG_DONTWAIT, &err);
+
+	if (skb==NULL) {
+		dev_unlock_list();
+		return err;
+	}
+
+	skb_reserve(skb, (dev->hard_header_len+15)&~15);
+	skb->mac.raw = skb->nh.raw = skb->data;
+
+	if (dev->hard_header) {
+		if (dev->hard_header(skb, dev, ntohs(proto),
+				     saddr ? saddr->sll_addr : NULL,
+				     NULL, len) < 0
+		    && sock->type == SOCK_DGRAM) {
+			kfree_skb(skb, FREE_WRITE);
+			dev_unlock_list();
+			return -EINVAL;
+		}
+		skb->mac.raw = skb->data;
+		if (sock->type != SOCK_DGRAM) {
+			skb->tail = skb->data;
+			skb->len = 0;
+		}
+	}
+
+	err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
+	skb->arp = 1;	/* No ARP needs doing on this (complete) frame */
+	skb->protocol = proto;
+	skb->dev = dev;
+	skb->priority = sk->priority;
+	dev_unlock_list();
+
+	/*
+	 *	Now send it
+	 */
+
+	if (err) {
+		err = -EFAULT;
+	} else {
+		if (!(dev->flags & IFF_UP))
+			err = -ENETDOWN;
+	}
+
+	if (err) {
+		kfree_skb(skb, FREE_WRITE);
+		return err;
+	}
+
+	dev_queue_xmit(skb);
+	return(len);
+}
+
+static void packet_destroy_timer(unsigned long data)
+{
+	struct sock *sk=(struct sock *)data;
+
+	if (!atomic_read(&sk->wmem_alloc) && !atomic_read(&sk->rmem_alloc)) {
+		sk_free(sk);
+		MOD_DEC_USE_COUNT;
+		return;
+	}
+
+	sk->timer.expires=jiffies+10*HZ;
+	add_timer(&sk->timer);
+	printk(KERN_DEBUG "packet sk destroy delayed\n");
+}
+
+/*
+ *	Close a PACKET socket. This is fairly simple. We immediately go
+ *	to 'closed' state and remove our protocol entry in the device list.
+ */
+
+static int packet_release(struct socket *sock, struct socket *peersock)
+{
+	struct sk_buff	*skb;
+	struct sock *sk = sock->sk;
+
+	if (!sk)
+		return 0;
+
+	sklist_remove_socket(&packet_sklist, sk);
+
+	/*
+	 *	Unhook packet receive handler.
+	 */
+
+	if (sk->protinfo.af_packet->running)
+	{
+		/*
+		 *	Remove the protocol hook
+		 */
+		 
+		dev_remove_pack(&sk->protinfo.af_packet->prot_hook);
+		sk->protinfo.af_packet->running = 0;
+	}
+
+#ifdef CONFIG_PACKET_MULTICAST
+	packet_flush_mclist(sk);
+#endif
+
+	/*
+	 *	Now the socket is dead. No more input will appear.
+	 */
+
+	sk->state_change(sk);	/* It is useless. Just for sanity. */
+
+	sock->sk = NULL;
+	sk->socket = NULL;
+	sk->dead = 1;
+
+	/* Purge queues */
+
+	while ((skb=skb_dequeue(&sk->receive_queue))!=NULL)
+		kfree_skb(skb,FREE_READ);
+
+	if (atomic_read(&sk->rmem_alloc) || atomic_read(&sk->wmem_alloc)) {
+		sk->timer.data=(unsigned long)sk;
+		sk->timer.expires=jiffies+HZ;
+		sk->timer.function=packet_destroy_timer;
+		add_timer(&sk->timer);
+		return 0;
+	}
+
+	sk_free(sk);
+	MOD_DEC_USE_COUNT;
+	return 0;
+}
+
+/*
+ *	Attach a packet hook.
+ */
+
+static int packet_do_bind(struct sock *sk, struct device *dev, int protocol)
+{
+	/*
+	 *	Detach an existing hook if present.
+	 */
+
+	if (sk->protinfo.af_packet->running) {
+		dev_remove_pack(&sk->protinfo.af_packet->prot_hook);
+		sk->protinfo.af_packet->running = 0;
+	}
+
+	sk->num = protocol;
+	sk->protinfo.af_packet->prot_hook.type = protocol;
+	sk->protinfo.af_packet->prot_hook.dev = dev;
+
+	if (protocol == 0)
+		return 0;
+
+	if (dev) {
+		sk->protinfo.af_packet->ifindex = dev->ifindex;
+		if (dev->flags&IFF_UP) {
+			dev_add_pack(&sk->protinfo.af_packet->prot_hook);
+			sk->protinfo.af_packet->running = 1;
+		} else {
+			sk->err = ENETDOWN;
+			sk->error_report(sk);
+		}
+	} else {
+		sk->protinfo.af_packet->ifindex = 0;
+		dev_add_pack(&sk->protinfo.af_packet->prot_hook);
+		sk->protinfo.af_packet->running = 1;
+	}
+	return 0;
+}
+
+/*
+ *	Bind a packet socket to a device
+ */
+
+#ifdef CONFIG_SOCK_PACKET
+
+static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sock *sk=sock->sk;
+	char name[15];
+	struct device *dev;
+	
+	/*
+	 *	Check legality
+	 */
+	 
+	if(addr_len!=sizeof(struct sockaddr))
+		return -EINVAL;
+	strncpy(name,uaddr->sa_data,14);
+	name[14]=0;
+
+	dev = dev_get(name);
+	if (dev)
+		return packet_do_bind(sk, dev, sk->num);
+	return -ENODEV;
+}
+#endif
+
+static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+	struct sockaddr_ll *sll = (struct sockaddr_ll*)uaddr;
+	struct sock *sk=sock->sk;
+	struct device *dev = NULL;
+	
+	/*
+	 *	Check legality
+	 */
+	 
+	if (addr_len < sizeof(struct sockaddr_ll))
+		return -EINVAL;
+	if (sll->sll_family != AF_PACKET)
+		return -EINVAL;
+
+	if (sll->sll_ifindex) {
+		dev = dev_get_by_index(sll->sll_ifindex);
+		if (dev == NULL)
+			return -ENODEV;
+	}
+	return packet_do_bind(sk, dev, sll->sll_protocol ? : sk->num);
+}
+
+
+/*
+ *	Create a packet of type SOCK_PACKET. 
+ */
+
+static int packet_create(struct socket *sock, int protocol)
+{
+	struct sock *sk;
+
+	if (!suser())
+		return -EPERM;
+	if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW
+#ifdef CONFIG_SOCK_PACKET
+	    && sock->type != SOCK_PACKET
+#endif
+	    )
+		return -ESOCKTNOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+	MOD_INC_USE_COUNT;
+	sk = sk_alloc(AF_PACKET, GFP_KERNEL);
+	if (sk == NULL) {
+		MOD_DEC_USE_COUNT;
+		return -ENOBUFS;
+	}
+
+	sk->reuse = 1;
+#ifdef CONFIG_SOCK_PACKET
+	if (sock->type == SOCK_PACKET)
+		sock->ops = &packet_ops_spkt;
+	else
+#endif
+	sock->ops = &packet_ops;
+	sock_init_data(sock,sk);
+
+	sk->protinfo.af_packet = kmalloc(sizeof(struct packet_opt), GFP_KERNEL);
+	if (sk->protinfo.af_packet == NULL) {
+		sk_free(sk);
+		MOD_DEC_USE_COUNT;
+		return -ENOBUFS;
+	}
+	memset(sk->protinfo.af_packet, 0, sizeof(struct packet_opt));
+	sk->zapped=0;
+	sk->family = AF_PACKET;
+	sk->num = protocol;
+
+	/*
+	 *	Attach a protocol block
+	 */
+
+#ifdef CONFIG_SOCK_PACKET
+	if (sock->type == SOCK_PACKET)
+		sk->protinfo.af_packet->prot_hook.func = packet_rcv_spkt;
+	else
+#endif
+	sk->protinfo.af_packet->prot_hook.func = packet_rcv;
+
+	sk->protinfo.af_packet->prot_hook.data = (void *)sk;
+
+	if (protocol) {
+		sk->protinfo.af_packet->prot_hook.type = protocol;
+		dev_add_pack(&sk->protinfo.af_packet->prot_hook);
+		sk->protinfo.af_packet->running = 1;
+	}
+
+	sklist_insert_socket(&packet_sklist, sk);
+	return(0);
+}
+
+/*
+ *	Pull a packet from our receive queue and hand it to the user.
+ *	If necessary we block.
+ */
+
+/*
+ *	NOTE about lock_* & release_* primitives.
+ *	I do not understand why skb_recv_datagram locks socket.
+ *	My analysis shows that it is useless for datagram services:
+ *	i.e. here, udp, raw and netlink. FIX ME if I am wrong,
+ *	but lock&release are necessary only for SOCK_STREAM
+ *	and, maybe, SOCK_SEQPACKET.
+ *							--ANK
+ */
+
+static int packet_recvmsg(struct socket *sock, struct msghdr *msg, int len,
+			  int flags, struct scm_cookie *scm)
+{
+	struct sock *sk = sock->sk;
+	int copied=0;
+	struct sk_buff *skb;
+	int err;
+
+#if 0
+	/* What error should we return now? EUNATTACH? */
+	if (sk->protinfo.af_packet->ifindex < 0)
+		return -ENODEV;
+#endif
+
+	/*
+	 *	If the address length field is there to be filled in, we fill
+	 *	it in now.
+	 */
+
+	if (sock->type == SOCK_PACKET)
+		msg->msg_namelen = sizeof(struct sockaddr_pkt);
+	else
+		msg->msg_namelen = sizeof(struct sockaddr_ll);
+
+	/*
+	 *	Call the generic datagram receiver. This handles all sorts
+	 *	of horrible races and re-entrancy so we can forget about it
+	 *	in the protocol layers.
+	 *
+	 *	Now it will return ENETDOWN, if device have just gone down,
+	 *	but then it will block.
+	 */
+
+	skb=skb_recv_datagram(sk,flags,flags&MSG_DONTWAIT,&err);
+
+	/*
+	 *	An error occurred so return it. Because skb_recv_datagram() 
+	 *	handles the blocking we don't see and worry about blocking
+	 *	retries.
+	 */
+
+	if(skb==NULL)
+		return err;
+
+	/*
+	 *	You lose any data beyond the buffer you gave. If it worries a
+	 *	user program they can ask the device for its MTU anyway.
+	 */
+
+	copied = skb->len;
+	if(copied>len)
+	{
+		copied=len;
+		msg->msg_flags|=MSG_TRUNC;
+	}
+
+	/* We can't use skb_copy_datagram here */
+	err = memcpy_toiovec(msg->msg_iov, skb->data, copied);
+	if (err)
+	{
+		return -EFAULT;
+	}
+
+	sk->stamp=skb->stamp;
+
+	if (msg->msg_name)
+		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
+
+	/*
+	 *	Free or return the buffer as appropriate. Again this hides all the
+	 *	races and re-entrancy issues from us.
+	 */
+
+	skb_free_datagram(sk, skb);
+
+	return(copied);
+}
+
+#ifdef CONFIG_SOCK_PACKET
+static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
+			       int *uaddr_len, int peer)
+{
+	struct device *dev;
+	struct sock *sk	= sock->sk;
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	uaddr->sa_family = AF_PACKET;
+	dev = dev_get_by_index(sk->protinfo.af_packet->ifindex);
+	if (dev)
+		strncpy(uaddr->sa_data, dev->name, 15);
+	else
+		memset(uaddr->sa_data, 0, 14);
+	*uaddr_len = sizeof(*uaddr);
+
+	return 0;
+}
+#endif
+
+static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
+			  int *uaddr_len, int peer)
+{
+	struct device *dev;
+	struct sock *sk = sock->sk;
+	struct sockaddr_ll *sll = (struct sockaddr_ll*)uaddr;
+
+	if (peer)
+		return -EOPNOTSUPP;
+
+	sll->sll_family = AF_PACKET;
+	sll->sll_ifindex = sk->protinfo.af_packet->ifindex;
+	sll->sll_protocol = sk->num;
+	dev = dev_get_by_index(sk->protinfo.af_packet->ifindex);
+	if (dev) {
+		sll->sll_hatype = dev->type;
+		sll->sll_halen = dev->addr_len;
+		memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
+	} else {
+		sll->sll_hatype = 0;	/* Bad: we have no ARPHRD_UNSPEC */
+		sll->sll_halen = 0;
+	}
+	*uaddr_len = sizeof(*sll);
+
+	return 0;
+}
+
+#ifdef CONFIG_PACKET_MULTICAST
+static void packet_dev_mc(struct device *dev, struct packet_mclist *i, int what)
+{
+	switch (i->type) {
+	case PACKET_MR_MULTICAST:
+		if (what > 0)
+			dev_mc_add(dev, i->addr, i->alen, 0);
+		else
+			dev_mc_delete(dev, i->addr, i->alen, 0);
+		break;
+	case PACKET_MR_PROMISC:
+		dev_set_promiscuity(dev, what);
+		break;
+	case PACKET_MR_ALLMULTI:
+		dev_set_allmulti(dev, what);
+		break;
+	default:
+	}
+}
+
+static void packet_dev_mclist(struct device *dev, struct packet_mclist *i, int what)
+{
+	for ( ; i; i=i->next) {
+		if (i->ifindex == dev->ifindex)
+			packet_dev_mc(dev, i, what);
+	}
+}
+
+static int packet_mc_add(struct sock *sk, struct packet_mreq *mreq)
+{
+	int err;
+	struct packet_mclist *ml, *i;
+	struct device *dev;
+
+	rtnl_shlock();
+
+	dev = dev_get_by_index(mreq->mr_ifindex);
+
+	i = NULL;
+	err = -ENODEV;
+	if (!dev)
+		goto done;
+	err = -EINVAL;
+	if (mreq->mr_alen > dev->addr_len)
+		goto done;
+
+	i = (struct packet_mclist *)kmalloc(sizeof(*i), GFP_KERNEL);
+
+	for (ml=sk->protinfo.af_packet->mclist; ml; ml=ml->next) {
+		if (ml->ifindex == mreq->mr_ifindex &&
+		    ml->type == mreq->mr_type &&
+		    ml->alen == mreq->mr_alen &&
+		    memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
+			ml->count++;
+			err = 0;
+			goto done;
+		}
+	}
+	err = -ENOBUFS;
+	if (i == NULL)
+		goto done;
+	i->type = mreq->mr_type;
+	i->ifindex = mreq->mr_ifindex;
+	i->alen = mreq->mr_alen;
+	memcpy(i->addr, mreq->mr_address, i->alen);
+	i->count = 1;
+	i->next = sk->protinfo.af_packet->mclist;
+	sk->protinfo.af_packet->mclist = i;
+	packet_dev_mc(dev, i, +1);
+	i = NULL;
+	err = 0;
+
+done:
+	rtnl_shunlock();
+	if (i)
+		kfree(i);
+	return err;
+}
+
+static int packet_mc_drop(struct sock *sk, struct packet_mreq *mreq)
+{
+	struct packet_mclist *ml, **mlp;
+
+	for (mlp=&sk->protinfo.af_packet->mclist; (ml=*mlp)!=NULL; mlp=&ml->next) {
+		if (ml->ifindex == mreq->mr_ifindex &&
+		    ml->type == mreq->mr_type &&
+		    ml->alen == mreq->mr_alen &&
+		    memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
+			if (--ml->count == 0) {
+				struct device *dev;
+				*mlp = ml->next;
+				dev = dev_get_by_index(ml->ifindex);
+				if (dev)
+					packet_dev_mc(dev, ml, -1);
+				kfree_s(ml, sizeof(*ml));
+			}
+			return 0;
+		}
+	}
+	return -EADDRNOTAVAIL;
+}
+
+static void packet_flush_mclist(struct sock *sk)
+{
+	struct packet_mclist *ml;
+
+	while ((ml=sk->protinfo.af_packet->mclist) != NULL) {
+		struct device *dev;
+		sk->protinfo.af_packet->mclist = ml->next;
+		if ((dev = dev_get_by_index(ml->ifindex)) != NULL)
+			packet_dev_mc(dev, ml, -1);
+		kfree_s(ml, sizeof(*ml));
+	}
+}
+
+static int
+packet_setsockopt(struct socket *sock, int level, int optname, char *optval, int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct packet_mreq mreq;
+
+	if (level != SOL_PACKET)
+		return -ENOPROTOOPT;
+	
+	switch(optname)	{
+	case PACKET_ADD_MEMBERSHIP:	
+	case PACKET_DROP_MEMBERSHIP:
+			
+		if (optlen<sizeof(mreq))
+			return -EINVAL;
+		if (copy_from_user(&mreq,optval,sizeof(mreq)))
+			return -EFAULT;
+		if (optname == PACKET_ADD_MEMBERSHIP)
+			return packet_mc_add(sk, &mreq);
+		else
+			return packet_mc_drop(sk, &mreq);
+	default:	
+		return -ENOPROTOOPT;
+	}
+}
+#endif
+
+static int packet_notifier(struct notifier_block *this, unsigned long msg, void *data)
+{
+	struct sock *sk;
+	struct packet_opt *po;
+	struct device *dev = (struct device*)data;
+
+	for (sk = packet_sklist; sk; sk = sk->next) {
+		po = sk->protinfo.af_packet;
+
+		switch (msg) {
+		case NETDEV_DOWN:
+		case NETDEV_UNREGISTER:
+			if (dev->ifindex == po->ifindex) {
+				if (po->running) {
+					dev_remove_pack(&po->prot_hook);
+					po->running = 0;
+					sk->err = ENETDOWN;
+					sk->error_report(sk);
+				}
+				if (msg == NETDEV_UNREGISTER) {
+					po->ifindex = -1;
+					po->prot_hook.dev = NULL;
+				}
+			}
+#ifdef CONFIG_PACKET_MULTICAST
+			if (po->mclist)
+				packet_dev_mclist(dev, po->mclist, -1);
+#endif
+			break;
+		case NETDEV_UP:
+			if (dev->ifindex == po->ifindex && sk->num && po->running==0) {
+				dev_add_pack(&po->prot_hook);
+				po->running = 1;
+			}
+#ifdef CONFIG_PACKET_MULTICAST
+			if (po->mclist)
+				packet_dev_mclist(dev, po->mclist, +1);
+#endif
+			break;
+		}
+	}
+	return NOTIFY_DONE;
+}
+
+
+static int packet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	struct sock *sk = sock->sk;
+	int err;
+	int pid;
+
+	switch(cmd) 
+	{
+		case FIOSETOWN:
+		case SIOCSPGRP:
+			err = get_user(pid, (int *) arg);
+			if (err)
+				return err; 
+			if (current->pid != pid && current->pgrp != -pid && !suser())
+				return -EPERM;
+			sk->proc = pid;
+			return(0);
+		case FIOGETOWN:
+		case SIOCGPGRP:
+			return put_user(sk->proc, (int *)arg);
+			return(0);			
+		case SIOCGSTAMP:
+			if(sk->stamp.tv_sec==0)
+				return -ENOENT;
+			err = copy_to_user((void *)arg,&sk->stamp,sizeof(struct timeval));
+			if (err)
+				err = -EFAULT;
+			return err;
+		case SIOCGIFFLAGS:
+		case SIOCSIFFLAGS:
+		case SIOCGIFCONF:
+		case SIOCGIFMETRIC:
+		case SIOCSIFMETRIC:
+		case SIOCGIFMEM:
+		case SIOCSIFMEM:
+		case SIOCGIFMTU:
+		case SIOCSIFMTU:
+		case SIOCSIFLINK:
+		case SIOCGIFHWADDR:
+		case SIOCSIFHWADDR:
+		case SIOCSIFMAP:
+		case SIOCGIFMAP:
+		case SIOCSIFSLAVE:
+		case SIOCGIFSLAVE:
+		case SIOCGIFINDEX:
+		case SIOCGIFNAME:
+		case SIOCGIFCOUNT:
+		case SIOCSIFHWBROADCAST:
+			return(dev_ioctl(cmd,(void *) arg));
+
+		case SIOCGIFBR:
+		case SIOCSIFBR:
+#ifdef CONFIG_BRIDGE		
+			return(br_ioctl(cmd,(void *) arg));
+#else
+			return -ENOPKG;
+#endif						
+			
+		case SIOCADDDLCI:
+		case SIOCDELDLCI:
+#ifdef CONFIG_DLCI
+			return(dlci_ioctl(cmd, (void *) arg));
+#endif
+
+#ifdef CONFIG_DLCI_MODULE
+
+#ifdef CONFIG_KERNELD
+			if (dlci_ioctl_hook == NULL)
+				request_module("dlci");
+#endif
+
+			if (dlci_ioctl_hook)
+				return((*dlci_ioctl_hook)(cmd, (void *) arg));
+#endif
+			return -ENOPKG;
+
+		default:
+			if ((cmd >= SIOCDEVPRIVATE) &&
+			    (cmd <= (SIOCDEVPRIVATE + 15)))
+				return(dev_ioctl(cmd,(void *) arg));
+
+#ifdef CONFIG_NET_RADIO
+			if((cmd >= SIOCIWFIRST) && (cmd <= SIOCIWLAST))
+				return(dev_ioctl(cmd,(void *) arg));
+#endif
+			return -EOPNOTSUPP;
+	}
+	/*NOTREACHED*/
+	return(0);
+}
+
+#ifdef CONFIG_SOCK_PACKET
+struct proto_ops packet_ops_spkt = {
+	AF_PACKET,
+
+	sock_no_dup,
+	packet_release,
+	packet_bind_spkt,
+	sock_no_connect,
+	NULL,
+	NULL,
+	packet_getname_spkt,
+	datagram_poll,
+	packet_ioctl,
+	sock_no_listen,
+	sock_no_shutdown,
+	sock_no_setsockopt,
+	sock_no_getsockopt,
+	sock_no_fcntl,
+	packet_sendmsg_spkt,
+	packet_recvmsg
+};
+#endif
+
+struct proto_ops packet_ops = {
+	AF_PACKET,
+
+	sock_no_dup,
+	packet_release,
+	packet_bind,
+	sock_no_connect,
+	NULL,
+	NULL,
+	packet_getname, 
+	datagram_poll,
+	packet_ioctl,
+	sock_no_listen,
+	sock_no_shutdown,
+#ifdef CONFIG_PACKET_MULTICAST
+	packet_setsockopt,
+#else
+	sock_no_setsockopt,
+#endif
+	sock_no_getsockopt,
+	sock_no_fcntl,
+	packet_sendmsg,
+	packet_recvmsg
+};
+
+static struct net_proto_family packet_family_ops = {
+	AF_PACKET,
+	packet_create
+};
+
+struct notifier_block packet_netdev_notifier={
+	packet_notifier,
+	NULL,
+	0
+};
+
+
+#ifdef MODULE
+void cleanup_module(void)
+{
+	unregister_netdevice_notifier(&packet_netdev_notifier);
+	sock_unregister(packet_family_ops.family);
+	return;
+}
+
+
+int init_module(void)
+#else
+__initfunc(void packet_proto_init(struct net_proto *pro))
+#endif
+{
+	sock_register(&packet_family_ops);
+	register_netdevice_notifier(&packet_netdev_notifier);
+#ifdef MODULE
+	return 0;
+#endif
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov