[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / core / datagram.c

/*
 *	SUCS NET3:
 *
 *	Generic datagram handling routines. These are generic for all
 *	protocols. Possibly a generic IP version on top of these would
 *	make sense. Not tonight however 8-).
 *	This is used because UDP, RAW, PACKET, DDP, IPX, AX.25 and
 *	NetROM layer all have identical poll code and mostly
 *	identical recvmsg() code. So we share it here. The poll was
 *	shared before but buried in udp.c so I moved it.
 *
 *	Authors:	Alan Cox <alan@redhat.com>. (datagram_poll() from old
 *						     udp.c code)
 *
 *	Fixes:
 *		Alan Cox	:	NULL return from skb_peek_copy()
 *					understood
 *		Alan Cox	:	Rewrote skb_read_datagram to avoid the
 *					skb_peek_copy stuff.
 *		Alan Cox	:	Added support for SOCK_SEQPACKET.
 *					IPX can no longer use the SO_TYPE hack
 *					but AX.25 now works right, and SPX is
 *					feasible.
 *		Alan Cox	:	Fixed write poll of non IP protocol
 *					crash.
 *		Florian  La Roche:	Changed for my new skbuff handling.
 *		Darryl Miles	:	Fixed non-blocking SOCK_SEQPACKET.
 *		Linus Torvalds	:	BSD semantic fixes.
 *		Alan Cox	:	Datagram iovec handling
 *		Darryl Miles	:	Fixed non-blocking SOCK_STREAM.
 *		Alan Cox	:	POSIXisms
 *		Pete Wyckoff    :       Unconnected accept() fix.
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/poll.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>

#include <net/protocol.h>
#include <linux/skbuff.h>

#include <net/checksum.h>
#include <net/sock.h>
#include <net/tcp_states.h>

/*
 *	Is a socket 'connection oriented' ?
 */
static inline int connection_based(struct sock *sk)
{
	return sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM;
}

/*
 * Wait for a packet..
 */
static int wait_for_packet(struct sock *sk, int *err, long *timeo_p)
{
	int error;
	DEFINE_WAIT(wait);

	prepare_to_wait_exclusive(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);

	/* Socket errors? */
	error = sock_error(sk);
	if (error)
		goto out_err;

	if (!skb_queue_empty(&sk->sk_receive_queue))
		goto out;

	/* Socket shut down? */
	if (sk->sk_shutdown & RCV_SHUTDOWN)
		goto out_noerr;

	/* Sequenced packets can come disconnected.
	 * If so we report the problem
	 */
	error = -ENOTCONN;
	if (connection_based(sk) &&
	    !(sk->sk_state == TCP_ESTABLISHED || sk->sk_state == TCP_LISTEN))
		goto out_err;

	/* handle signals */
	if (signal_pending(current))
		goto interrupted;

	error = 0;
	*timeo_p = schedule_timeout(*timeo_p);
out:
	finish_wait(sk->sk_sleep, &wait);
	return error;
interrupted:
	error = sock_intr_errno(*timeo_p);
out_err:
	*err = error;
	goto out;
out_noerr:
	*err = 0;
	error = 1;
	goto out;
}

/**
 *	skb_recv_datagram - Receive a datagram skbuff
 *	@sk: socket
 *	@flags: MSG_ flags
 *	@noblock: blocking operation?
 *	@err: error code returned
 *
 *	Get a datagram skbuff, understands the peeking, nonblocking wakeups
 *	and possible races. This replaces identical code in packet, raw and
 *	udp, as well as the IPX AX.25 and Appletalk. It also finally fixes
 *	the long standing peek and read race for datagram sockets. If you
 *	alter this routine remember it must be re-entrant.
 *
 *	This function will lock the socket if a skb is returned, so the caller
 *	needs to unlock the socket in that case (usually by calling
 *	skb_free_datagram)
 *
 *	* It does not lock socket since today. This function is
 *	* free of race conditions. This measure should/can improve
 *	* significantly datagram socket latencies at high loads,
 *	* when data copying to user space takes lots of time.
 *	* (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet
 *	*  8) Great win.)
 *	*			                    --ANK (980729)
 *
 *	The order of the tests when we find no data waiting are specified
 *	quite explicitly by POSIX 1003.1g, don't change them without having
 *	the standard around please.
 */
struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
				  int noblock, int *err)
{
	struct sk_buff *skb;
	long timeo;
	/*
	 * Caller is allowed not to check sk->sk_err before skb_recv_datagram()
	 */
	int error = sock_error(sk);

	if (error)
		goto no_packet;

	timeo = sock_rcvtimeo(sk, noblock);

	do {
		/* Again only user level code calls this function, so nothing
		 * interrupt level will suddenly eat the receive_queue.
		 *
		 * Look at current nfs client by the way...
		 * However, this function was corrent in any case. 8)
		 */
		if (flags & MSG_PEEK) {
			unsigned long cpu_flags;

			spin_lock_irqsave(&sk->sk_receive_queue.lock,
					  cpu_flags);
			skb = skb_peek(&sk->sk_receive_queue);
			if (skb)
				atomic_inc(&skb->users);
			spin_unlock_irqrestore(&sk->sk_receive_queue.lock,
					       cpu_flags);
		} else
			skb = skb_dequeue(&sk->sk_receive_queue);

		if (skb)
			return skb;

		/* User doesn't want to wait */
		error = -EAGAIN;
		if (!timeo)
			goto no_packet;

	} while (!wait_for_packet(sk, err, &timeo));

	return NULL;

no_packet:
	*err = error;
	return NULL;
}

void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
{
	kfree_skb(skb);
}

/**
 *	skb_kill_datagram - Free a datagram skbuff forcibly
 *	@sk: socket
 *	@skb: datagram skbuff
 *	@flags: MSG_ flags
 *
 *	This function frees a datagram skbuff that was received by
 *	skb_recv_datagram.  The flags argument must match the one
 *	used for skb_recv_datagram.
 *
 *	If the MSG_PEEK flag is set, and the packet is still on the
 *	receive queue of the socket, it will be taken off the queue
 *	before it is freed.
 *
 *	This function currently only disables BH when acquiring the
 *	sk_receive_queue lock.  Therefore it must not be used in a
 *	context where that lock is acquired in an IRQ context.
 */

void skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
{
	if (flags & MSG_PEEK) {
		spin_lock_bh(&sk->sk_receive_queue.lock);
		if (skb == skb_peek(&sk->sk_receive_queue)) {
			__skb_unlink(skb, &sk->sk_receive_queue);
			atomic_dec(&skb->users);
		}
		spin_unlock_bh(&sk->sk_receive_queue.lock);
	}

	kfree_skb(skb);
}

EXPORT_SYMBOL(skb_kill_datagram);

/**
 *	skb_copy_datagram_iovec - Copy a datagram to an iovec.
 *	@skb: buffer to copy
 *	@offset: offset in the buffer to start copying from
 *	@to: io vector to copy to
 *	@len: amount of data to copy from buffer to iovec
 *
 *	Note: the iovec is modified during the copy.
 */
int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
			    struct iovec *to, int len)
{
	int i, err, fraglen, end = 0;
	struct sk_buff *next = skb_shinfo(skb)->frag_list;

	if (!len)
		return 0;

next_skb:
	fraglen = skb_headlen(skb);
	i = -1;

	while (1) {
		int start = end;

		if ((end += fraglen) > offset) {
			int copy = end - offset, o = offset - start;

			if (copy > len)
				copy = len;
			if (i == -1)
				err = memcpy_toiovec(to, skb->data + o, copy);
			else {
				skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
				struct page *page = frag->page;
				void *p = kmap(page) + frag->page_offset + o;
				err = memcpy_toiovec(to, p, copy);
				kunmap(page);
			}
			if (err)
				goto fault;
			if (!(len -= copy))
				return 0;
			offset += copy;
		}
		if (++i >= skb_shinfo(skb)->nr_frags)
			break;
		fraglen = skb_shinfo(skb)->frags[i].size;
	}
	if (next) {
		skb = next;
		BUG_ON(skb_shinfo(skb)->frag_list);
		next = skb->next;
		goto next_skb;
	}
fault:
	return -EFAULT;
}

static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
				      u8 __user *to, int len,
				      unsigned int *csump)
{
	int start = skb_headlen(skb);
	int pos = 0;
	int i, copy = start - offset;

	/* Copy header. */
	if (copy > 0) {
		int err = 0;
		if (copy > len)
			copy = len;
		*csump = csum_and_copy_to_user(skb->data + offset, to, copy,
					       *csump, &err);
		if (err)
			goto fault;
		if ((len -= copy) == 0)
			return 0;
		offset += copy;
		to += copy;
		pos = copy;
	}

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		int end;

		BUG_TRAP(start <= offset + len);

		end = start + skb_shinfo(skb)->frags[i].size;
		if ((copy = end - offset) > 0) {
			unsigned int csum2;
			int err = 0;
			u8  *vaddr;
			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
			struct page *page = frag->page;

			if (copy > len)
				copy = len;
			vaddr = kmap(page);
			csum2 = csum_and_copy_to_user(vaddr +
							frag->page_offset +
							offset - start,
						      to, copy, 0, &err);
			kunmap(page);
			if (err)
				goto fault;
			*csump = csum_block_add(*csump, csum2, pos);
			if (!(len -= copy))
				return 0;
			offset += copy;
			to += copy;
			pos += copy;
		}
		start = end;
	}

	if (skb_shinfo(skb)->frag_list) {
		struct sk_buff *list = skb_shinfo(skb)->frag_list;

		for (; list; list=list->next) {
			int end;

			BUG_TRAP(start <= offset + len);

			end = start + list->len;
			if ((copy = end - offset) > 0) {
				unsigned int csum2 = 0;
				if (copy > len)
					copy = len;
				if (skb_copy_and_csum_datagram(list,
							       offset - start,
							       to, copy,
							       &csum2))
					goto fault;
				*csump = csum_block_add(*csump, csum2, pos);
				if ((len -= copy) == 0)
					return 0;
				offset += copy;
				to += copy;
				pos += copy;
			}
			start = end;
		}
	}
	if (!len)
		return 0;

fault:
	return -EFAULT;
}

unsigned int __skb_checksum_complete(struct sk_buff *skb)
{
	unsigned int sum;

	sum = (u16)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
	if (likely(!sum)) {
		if (unlikely(skb->ip_summed == CHECKSUM_HW))
			netdev_rx_csum_fault(skb->dev);
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	}
	return sum;
}
EXPORT_SYMBOL(__skb_checksum_complete);

/**
 *	skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec.
 *	@skb: skbuff
 *	@hlen: hardware length
 *	@iov: io vector
 * 
 *	Caller _must_ check that skb will fit to this iovec.
 *
 *	Returns: 0       - success.
 *		 -EINVAL - checksum failure.
 *		 -EFAULT - fault during copy. Beware, in this case iovec
 *			   can be modified!
 */
int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
				     int hlen, struct iovec *iov)
{
	unsigned int csum;
	int chunk = skb->len - hlen;

	/* Skip filled elements.
	 * Pretty silly, look at memcpy_toiovec, though 8)
	 */
	while (!iov->iov_len)
		iov++;

	if (iov->iov_len < chunk) {
		if (__skb_checksum_complete(skb))
			goto csum_error;
		if (skb_copy_datagram_iovec(skb, hlen, iov, chunk))
			goto fault;
	} else {
		csum = csum_partial(skb->data, hlen, skb->csum);
		if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base,
					       chunk, &csum))
			goto fault;
		if ((unsigned short)csum_fold(csum))
			goto csum_error;
		if (unlikely(skb->ip_summed == CHECKSUM_HW))
			netdev_rx_csum_fault(skb->dev);
		iov->iov_len -= chunk;
		iov->iov_base += chunk;
	}
	return 0;
csum_error:
	return -EINVAL;
fault:
	return -EFAULT;
}

/**
 * 	datagram_poll - generic datagram poll
 *	@file: file struct
 *	@sock: socket
 *	@wait: poll table
 *
 *	Datagram poll: Again totally generic. This also handles
 *	sequenced packet sockets providing the socket receive queue
 *	is only ever holding data ready to receive.
 *
 *	Note: when you _don't_ use this routine for this protocol,
 *	and you use a different write policy from sock_writeable()
 *	then please supply your own write_space callback.
 */
unsigned int datagram_poll(struct file *file, struct socket *sock,
			   poll_table *wait)
{
	struct sock *sk = sock->sk;
	unsigned int mask;

	poll_wait(file, sk->sk_sleep, wait);
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
	if (!skb_queue_empty(&sk->sk_receive_queue) ||
	    (sk->sk_shutdown & RCV_SHUTDOWN))
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
	if (connection_based(sk)) {
		if (sk->sk_state == TCP_CLOSE)
			mask |= POLLHUP;
		/* connection hasn't started yet? */
		if (sk->sk_state == TCP_SYN_SENT)
			return mask;
	}

	/* writable? */
	if (sock_writeable(sk))
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}

EXPORT_SYMBOL(datagram_poll);
EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec);
EXPORT_SYMBOL(skb_copy_datagram_iovec);
EXPORT_SYMBOL(skb_free_datagram);
EXPORT_SYMBOL(skb_recv_datagram);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* SUCS NET3:
	3	*
	4	* Generic datagram handling routines. These are generic for all
	5	* protocols. Possibly a generic IP version on top of these would
	6	* make sense. Not tonight however 8-).
	7	* This is used because UDP, RAW, PACKET, DDP, IPX, AX.25 and
	8	* NetROM layer all have identical poll code and mostly
	9	* identical recvmsg() code. So we share it here. The poll was
	10	* shared before but buried in udp.c so I moved it.
	11	*
	12	* Authors: Alan Cox <alan@redhat.com>. (datagram_poll() from old
	13	* udp.c code)
	14	*
	15	* Fixes:
	16	* Alan Cox : NULL return from skb_peek_copy()
	17	* understood
	18	* Alan Cox : Rewrote skb_read_datagram to avoid the
	19	* skb_peek_copy stuff.
	20	* Alan Cox : Added support for SOCK_SEQPACKET.
	21	* IPX can no longer use the SO_TYPE hack
	22	* but AX.25 now works right, and SPX is
	23	* feasible.
	24	* Alan Cox : Fixed write poll of non IP protocol
	25	* crash.
	26	* Florian La Roche: Changed for my new skbuff handling.
	27	* Darryl Miles : Fixed non-blocking SOCK_SEQPACKET.
	28	* Linus Torvalds : BSD semantic fixes.
	29	* Alan Cox : Datagram iovec handling
	30	* Darryl Miles : Fixed non-blocking SOCK_STREAM.
	31	* Alan Cox : POSIXisms
	32	* Pete Wyckoff : Unconnected accept() fix.
	33	*
	34	*/
	35
	36	#include <linux/module.h>
	37	#include <linux/types.h>
	38	#include <linux/kernel.h>
	39	#include <asm/uaccess.h>
	40	#include <asm/system.h>
	41	#include <linux/mm.h>
	42	#include <linux/interrupt.h>
	43	#include <linux/errno.h>
	44	#include <linux/sched.h>
	45	#include <linux/inet.h>
1da177e4 LT	46	#include <linux/netdevice.h>
	47	#include <linux/rtnetlink.h>
	48	#include <linux/poll.h>
	49	#include <linux/highmem.h>
3305b80c	50	#include <linux/spinlock.h>
1da177e4 LT	51
	52	#include <net/protocol.h>
	53	#include <linux/skbuff.h>
1da177e4	54
c752f073 ACM	55	#include <net/checksum.h>
	56	#include <net/sock.h>
	57	#include <net/tcp_states.h>
1da177e4 LT	58
	59	/*
	60	* Is a socket 'connection oriented' ?
	61	*/
	62	static inline int connection_based(struct sock *sk)
	63	{
	64	return sk->sk_type == SOCK_SEQPACKET \|\| sk->sk_type == SOCK_STREAM;
	65	}
	66
	67	/*
	68	* Wait for a packet..
	69	*/
	70	static int wait_for_packet(struct sock sk, int err, long *timeo_p)
	71	{
	72	int error;
	73	DEFINE_WAIT(wait);
	74
	75	prepare_to_wait_exclusive(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
	76
	77	/* Socket errors? */
	78	error = sock_error(sk);
	79	if (error)
	80	goto out_err;
	81
	82	if (!skb_queue_empty(&sk->sk_receive_queue))
	83	goto out;
	84
	85	/* Socket shut down? */
	86	if (sk->sk_shutdown & RCV_SHUTDOWN)
	87	goto out_noerr;
	88
	89	/* Sequenced packets can come disconnected.
	90	* If so we report the problem
	91	*/
	92	error = -ENOTCONN;
	93	if (connection_based(sk) &&
	94	!(sk->sk_state == TCP_ESTABLISHED \|\| sk->sk_state == TCP_LISTEN))
	95	goto out_err;
	96
	97	/* handle signals */
	98	if (signal_pending(current))
	99	goto interrupted;
	100
	101	error = 0;
	102	timeo_p = schedule_timeout(timeo_p);
	103	out:
	104	finish_wait(sk->sk_sleep, &wait);
	105	return error;
	106	interrupted:
	107	error = sock_intr_errno(*timeo_p);
	108	out_err:
	109	*err = error;
	110	goto out;
	111	out_noerr:
	112	*err = 0;
	113	error = 1;
	114	goto out;
	115	}
	116
	117	/**
	118	* skb_recv_datagram - Receive a datagram skbuff
4dc3b16b PP	119	* @sk: socket
	120	* @flags: MSG_ flags
	121	* @noblock: blocking operation?
	122	* @err: error code returned
1da177e4 LT	123	*
	124	* Get a datagram skbuff, understands the peeking, nonblocking wakeups
	125	* and possible races. This replaces identical code in packet, raw and
	126	* udp, as well as the IPX AX.25 and Appletalk. It also finally fixes
	127	* the long standing peek and read race for datagram sockets. If you
	128	* alter this routine remember it must be re-entrant.
	129	*
	130	* This function will lock the socket if a skb is returned, so the caller
	131	* needs to unlock the socket in that case (usually by calling
	132	* skb_free_datagram)
	133	*
	134	* * It does not lock socket since today. This function is
	135	* * free of race conditions. This measure should/can improve
	136	* * significantly datagram socket latencies at high loads,
	137	* * when data copying to user space takes lots of time.
	138	* * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet
	139	* * 8) Great win.)
	140	* * --ANK (980729)
	141	*
	142	* The order of the tests when we find no data waiting are specified
	143	* quite explicitly by POSIX 1003.1g, don't change them without having
	144	* the standard around please.
	145	*/
	146	struct sk_buff skb_recv_datagram(struct sock sk, unsigned flags,
	147	int noblock, int *err)
	148	{
	149	struct sk_buff *skb;
	150	long timeo;
	151	/*
	152	* Caller is allowed not to check sk->sk_err before skb_recv_datagram()
	153	*/
	154	int error = sock_error(sk);
	155
	156	if (error)
	157	goto no_packet;
	158
	159	timeo = sock_rcvtimeo(sk, noblock);
	160
	161	do {
	162	/* Again only user level code calls this function, so nothing
	163	* interrupt level will suddenly eat the receive_queue.
	164	*
	165	* Look at current nfs client by the way...
	166	* However, this function was corrent in any case. 8)
	167	*/
	168	if (flags & MSG_PEEK) {
	169	unsigned long cpu_flags;
	170
	171	spin_lock_irqsave(&sk->sk_receive_queue.lock,
	172	cpu_flags);
	173	skb = skb_peek(&sk->sk_receive_queue);
	174	if (skb)
	175	atomic_inc(&skb->users);
	176	spin_unlock_irqrestore(&sk->sk_receive_queue.lock,
	177	cpu_flags);
	178	} else
	179	skb = skb_dequeue(&sk->sk_receive_queue);
	180
	181	if (skb)
	182	return skb;
	183
	184	/* User doesn't want to wait */
	185	error = -EAGAIN;
	186	if (!timeo)
187	goto no_packet;
188
189	} while (!wait_for_packet(sk, err, &timeo));
190
191	return NULL;
192
193	no_packet:
194	*err = error;
195	return NULL;
196	}
197
198	void skb_free_datagram(struct sock sk, struct sk_buff skb)
199	{
200	kfree_skb(skb);
201	}
202
3305b80c HX	203	/**
	204	* skb_kill_datagram - Free a datagram skbuff forcibly
	205	* @sk: socket
	206	* @skb: datagram skbuff
	207	* @flags: MSG_ flags
	208	*
	209	* This function frees a datagram skbuff that was received by
	210	* skb_recv_datagram. The flags argument must match the one
	211	* used for skb_recv_datagram.
	212	*
	213	* If the MSG_PEEK flag is set, and the packet is still on the
	214	* receive queue of the socket, it will be taken off the queue
	215	* before it is freed.
	216	*
	217	* This function currently only disables BH when acquiring the
	218	* sk_receive_queue lock. Therefore it must not be used in a
	219	* context where that lock is acquired in an IRQ context.
	220	*/
	221
	222	void skb_kill_datagram(struct sock sk, struct sk_buff skb, unsigned int flags)
	223	{
	224	if (flags & MSG_PEEK) {
	225	spin_lock_bh(&sk->sk_receive_queue.lock);
	226	if (skb == skb_peek(&sk->sk_receive_queue)) {
	227	__skb_unlink(skb, &sk->sk_receive_queue);
	228	atomic_dec(&skb->users);
	229	}
	230	spin_unlock_bh(&sk->sk_receive_queue.lock);
	231	}
	232
	233	kfree_skb(skb);
	234	}
	235
	236	EXPORT_SYMBOL(skb_kill_datagram);
	237
1da177e4 LT	238	/**
1da177e4 LT	239	* skb_copy_datagram_iovec - Copy a datagram to an iovec.
4dc3b16b PP	240	* @skb: buffer to copy
4dc3b16b PP	241	* @offset: offset in the buffer to start copying from
67be2dd1	242	* @to: io vector to copy to
4dc3b16b	243	* @len: amount of data to copy from buffer to iovec
1da177e4 LT	244	*
	245	* Note: the iovec is modified during the copy.
	246	*/
	247	int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
	248	struct iovec *to, int len)
	249	{
bc8dfcb9 DP	250	int i, err, fraglen, end = 0;
bc8dfcb9 DP	251	struct sk_buff *next = skb_shinfo(skb)->frag_list;
c75d721c HX	252
	253	if (!len)
	254	return 0;
	255
bc8dfcb9 DP	256	next_skb:
	257	fraglen = skb_headlen(skb);
	258	i = -1;
1da177e4	259
bc8dfcb9 DP	260	while (1) {
bc8dfcb9 DP	261	int start = end;
1da177e4	262
bc8dfcb9 DP	263	if ((end += fraglen) > offset) {
bc8dfcb9 DP	264	int copy = end - offset, o = offset - start;
1da177e4 LT	265
	266	if (copy > len)
	267	copy = len;
bc8dfcb9 DP	268	if (i == -1)
	269	err = memcpy_toiovec(to, skb->data + o, copy);
	270	else {
	271	skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
	272	struct page *page = frag->page;
	273	void *p = kmap(page) + frag->page_offset + o;
	274	err = memcpy_toiovec(to, p, copy);
	275	kunmap(page);
	276	}
1da177e4 LT	277	if (err)
	278	goto fault;
	279	if (!(len -= copy))
	280	return 0;
	281	offset += copy;
	282	}
bc8dfcb9 DP	283	if (++i >= skb_shinfo(skb)->nr_frags)
	284	break;
	285	fraglen = skb_shinfo(skb)->frags[i].size;
1da177e4	286	}
bc8dfcb9 DP	287	if (next) {
	288	skb = next;
	289	BUG_ON(skb_shinfo(skb)->frag_list);
	290	next = skb->next;
	291	goto next_skb;
1da177e4	292	}
1da177e4 LT	293	fault:
	294	return -EFAULT;
	295	}
	296
	297	static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
	298	u8 __user *to, int len,
	299	unsigned int *csump)
	300	{
	301	int start = skb_headlen(skb);
	302	int pos = 0;
	303	int i, copy = start - offset;
	304
	305	/* Copy header. */
	306	if (copy > 0) {
	307	int err = 0;
	308	if (copy > len)
	309	copy = len;
	310	*csump = csum_and_copy_to_user(skb->data + offset, to, copy,
	311	*csump, &err);
	312	if (err)
	313	goto fault;
	314	if ((len -= copy) == 0)
	315	return 0;
	316	offset += copy;
	317	to += copy;
	318	pos = copy;
	319	}
	320
	321	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
	322	int end;
	323
	324	BUG_TRAP(start <= offset + len);
	325
	326	end = start + skb_shinfo(skb)->frags[i].size;
	327	if ((copy = end - offset) > 0) {
	328	unsigned int csum2;
	329	int err = 0;
	330	u8 *vaddr;
	331	skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
	332	struct page *page = frag->page;
	333
	334	if (copy > len)
	335	copy = len;
	336	vaddr = kmap(page);
	337	csum2 = csum_and_copy_to_user(vaddr +
	338	frag->page_offset +
	339	offset - start,
	340	to, copy, 0, &err);
	341	kunmap(page);
	342	if (err)
	343	goto fault;
	344	csump = csum_block_add(csump, csum2, pos);
	345	if (!(len -= copy))
	346	return 0;
	347	offset += copy;
	348	to += copy;
	349	pos += copy;
	350	}
	351	start = end;
	352	}
	353
	354	if (skb_shinfo(skb)->frag_list) {
	355	struct sk_buff *list = skb_shinfo(skb)->frag_list;
	356
357	for (; list; list=list->next) {
358	int end;
359
360	BUG_TRAP(start <= offset + len);
361
362	end = start + list->len;
363	if ((copy = end - offset) > 0) {
364	unsigned int csum2 = 0;
365	if (copy > len)
366	copy = len;
367	if (skb_copy_and_csum_datagram(list,
368	offset - start,
369	to, copy,
370	&csum2))
371	goto fault;
372	csump = csum_block_add(csump, csum2, pos);
373	if ((len -= copy) == 0)
374	return 0;
375	offset += copy;
376	to += copy;
377	pos += copy;
378	}
379	start = end;
380	}
381	}
382	if (!len)
383	return 0;
384
385	fault:
386	return -EFAULT;
387	}
388
fb286bb2 HX	389	unsigned int __skb_checksum_complete(struct sk_buff *skb)
	390	{
	391	unsigned int sum;
	392
	393	sum = (u16)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
	394	if (likely(!sum)) {
	395	if (unlikely(skb->ip_summed == CHECKSUM_HW))
	396	netdev_rx_csum_fault(skb->dev);
	397	skb->ip_summed = CHECKSUM_UNNECESSARY;
	398	}
	399	return sum;
	400	}
	401	EXPORT_SYMBOL(__skb_checksum_complete);
	402
1da177e4 LT	403	/**
1da177e4 LT	404	* skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec.
4dc3b16b PP	405	* @skb: skbuff
4dc3b16b PP	406	* @hlen: hardware length
67be2dd1	407	* @iov: io vector
1da177e4 LT	408	*
	409	* Caller _must_ check that skb will fit to this iovec.
	410	*
	411	* Returns: 0 - success.
	412	* -EINVAL - checksum failure.
	413	* -EFAULT - fault during copy. Beware, in this case iovec
	414	* can be modified!
	415	*/
fb286bb2	416	int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
1da177e4 LT	417	int hlen, struct iovec *iov)
	418	{
	419	unsigned int csum;
	420	int chunk = skb->len - hlen;
	421
	422	/* Skip filled elements.
	423	* Pretty silly, look at memcpy_toiovec, though 8)
	424	*/
	425	while (!iov->iov_len)
	426	iov++;
	427
	428	if (iov->iov_len < chunk) {
fb286bb2	429	if (__skb_checksum_complete(skb))
1da177e4 LT	430	goto csum_error;
	431	if (skb_copy_datagram_iovec(skb, hlen, iov, chunk))
	432	goto fault;
	433	} else {
	434	csum = csum_partial(skb->data, hlen, skb->csum);
	435	if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base,
	436	chunk, &csum))
	437	goto fault;
	438	if ((unsigned short)csum_fold(csum))
	439	goto csum_error;
fb286bb2 HX	440	if (unlikely(skb->ip_summed == CHECKSUM_HW))
fb286bb2 HX	441	netdev_rx_csum_fault(skb->dev);
1da177e4 LT	442	iov->iov_len -= chunk;
	443	iov->iov_base += chunk;
	444	}
	445	return 0;
	446	csum_error:
	447	return -EINVAL;
	448	fault:
	449	return -EFAULT;
	450	}
	451
	452	/**
	453	* datagram_poll - generic datagram poll
4dc3b16b PP	454	* @file: file struct
	455	* @sock: socket
	456	* @wait: poll table
1da177e4 LT	457	*
	458	* Datagram poll: Again totally generic. This also handles
	459	* sequenced packet sockets providing the socket receive queue
	460	* is only ever holding data ready to receive.
	461	*
	462	* Note: when you _don't_ use this routine for this protocol,
	463	* and you use a different write policy from sock_writeable()
	464	* then please supply your own write_space callback.
	465	*/
	466	unsigned int datagram_poll(struct file file, struct socket sock,
	467	poll_table *wait)
	468	{
	469	struct sock *sk = sock->sk;
	470	unsigned int mask;
	471
	472	poll_wait(file, sk->sk_sleep, wait);
	473	mask = 0;
	474
	475	/* exceptional events? */
	476	if (sk->sk_err \|\| !skb_queue_empty(&sk->sk_error_queue))
	477	mask \|= POLLERR;
	478	if (sk->sk_shutdown == SHUTDOWN_MASK)
	479	mask \|= POLLHUP;
	480
	481	/* readable? */
	482	if (!skb_queue_empty(&sk->sk_receive_queue) \|\|
	483	(sk->sk_shutdown & RCV_SHUTDOWN))
	484	mask \|= POLLIN \| POLLRDNORM;
	485
	486	/* Connection-based need to check for termination and startup */
	487	if (connection_based(sk)) {
	488	if (sk->sk_state == TCP_CLOSE)
	489	mask \|= POLLHUP;
	490	/* connection hasn't started yet? */
	491	if (sk->sk_state == TCP_SYN_SENT)
	492	return mask;
	493	}
	494
	495	/* writable? */
	496	if (sock_writeable(sk))
	497	mask \|= POLLOUT \| POLLWRNORM \| POLLWRBAND;
	498	else
	499	set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
	500
	501	return mask;
	502	}
	503
	504	EXPORT_SYMBOL(datagram_poll);
	505	EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec);
	506	EXPORT_SYMBOL(skb_copy_datagram_iovec);
	507	EXPORT_SYMBOL(skb_free_datagram);
	508	EXPORT_SYMBOL(skb_recv_datagram);