skmsg.c 28.3 KB
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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */

#include <linux/skmsg.h>
#include <linux/skbuff.h>
#include <linux/scatterlist.h>

#include <net/sock.h>
#include <net/tcp.h>
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#include <net/tls.h>
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static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
{
	if (msg->sg.end > msg->sg.start &&
	    elem_first_coalesce < msg->sg.end)
		return true;

	if (msg->sg.end < msg->sg.start &&
	    (elem_first_coalesce > msg->sg.start ||
	     elem_first_coalesce < msg->sg.end))
		return true;

	return false;
}

int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
		 int elem_first_coalesce)
{
	struct page_frag *pfrag = sk_page_frag(sk);
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	u32 osize = msg->sg.size;
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	int ret = 0;

	len -= msg->sg.size;
	while (len > 0) {
		struct scatterlist *sge;
		u32 orig_offset;
		int use, i;

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		if (!sk_page_frag_refill(sk, pfrag)) {
			ret = -ENOMEM;
			goto msg_trim;
		}
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		orig_offset = pfrag->offset;
		use = min_t(int, len, pfrag->size - orig_offset);
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		if (!sk_wmem_schedule(sk, use)) {
			ret = -ENOMEM;
			goto msg_trim;
		}
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		i = msg->sg.end;
		sk_msg_iter_var_prev(i);
		sge = &msg->sg.data[i];

		if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
		    sg_page(sge) == pfrag->page &&
		    sge->offset + sge->length == orig_offset) {
			sge->length += use;
		} else {
			if (sk_msg_full(msg)) {
				ret = -ENOSPC;
				break;
			}

			sge = &msg->sg.data[msg->sg.end];
			sg_unmark_end(sge);
			sg_set_page(sge, pfrag->page, use, orig_offset);
			get_page(pfrag->page);
			sk_msg_iter_next(msg, end);
		}

		sk_mem_charge(sk, use);
		msg->sg.size += use;
		pfrag->offset += use;
		len -= use;
	}

	return ret;
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msg_trim:
	sk_msg_trim(sk, msg, osize);
	return ret;
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}
EXPORT_SYMBOL_GPL(sk_msg_alloc);

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int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
		 u32 off, u32 len)
{
	int i = src->sg.start;
	struct scatterlist *sge = sk_msg_elem(src, i);
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	struct scatterlist *sgd = NULL;
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	u32 sge_len, sge_off;

	while (off) {
		if (sge->length > off)
			break;
		off -= sge->length;
		sk_msg_iter_var_next(i);
		if (i == src->sg.end && off)
			return -ENOSPC;
		sge = sk_msg_elem(src, i);
	}

	while (len) {
		sge_len = sge->length - off;
		if (sge_len > len)
			sge_len = len;
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		if (dst->sg.end)
			sgd = sk_msg_elem(dst, dst->sg.end - 1);

		if (sgd &&
		    (sg_page(sge) == sg_page(sgd)) &&
		    (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
			sgd->length += sge_len;
			dst->sg.size += sge_len;
		} else if (!sk_msg_full(dst)) {
			sge_off = sge->offset + off;
			sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
		} else {
			return -ENOSPC;
		}

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		off = 0;
		len -= sge_len;
		sk_mem_charge(sk, sge_len);
		sk_msg_iter_var_next(i);
		if (i == src->sg.end && len)
			return -ENOSPC;
		sge = sk_msg_elem(src, i);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(sk_msg_clone);

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void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
{
	int i = msg->sg.start;

	do {
		struct scatterlist *sge = sk_msg_elem(msg, i);

		if (bytes < sge->length) {
			sge->length -= bytes;
			sge->offset += bytes;
			sk_mem_uncharge(sk, bytes);
			break;
		}

		sk_mem_uncharge(sk, sge->length);
		bytes -= sge->length;
		sge->length = 0;
		sge->offset = 0;
		sk_msg_iter_var_next(i);
	} while (bytes && i != msg->sg.end);
	msg->sg.start = i;
}
EXPORT_SYMBOL_GPL(sk_msg_return_zero);

void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
{
	int i = msg->sg.start;

	do {
		struct scatterlist *sge = &msg->sg.data[i];
		int uncharge = (bytes < sge->length) ? bytes : sge->length;

		sk_mem_uncharge(sk, uncharge);
		bytes -= uncharge;
		sk_msg_iter_var_next(i);
	} while (i != msg->sg.end);
}
EXPORT_SYMBOL_GPL(sk_msg_return);

static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
			    bool charge)
{
	struct scatterlist *sge = sk_msg_elem(msg, i);
	u32 len = sge->length;

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	/* When the skb owns the memory we free it from consume_skb path. */
	if (!msg->skb) {
		if (charge)
			sk_mem_uncharge(sk, len);
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		put_page(sg_page(sge));
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	}
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	memset(sge, 0, sizeof(*sge));
	return len;
}

static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
			 bool charge)
{
	struct scatterlist *sge = sk_msg_elem(msg, i);
	int freed = 0;

	while (msg->sg.size) {
		msg->sg.size -= sge->length;
		freed += sk_msg_free_elem(sk, msg, i, charge);
		sk_msg_iter_var_next(i);
		sk_msg_check_to_free(msg, i, msg->sg.size);
		sge = sk_msg_elem(msg, i);
	}
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	consume_skb(msg->skb);
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	sk_msg_init(msg);
	return freed;
}

int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
{
	return __sk_msg_free(sk, msg, msg->sg.start, false);
}
EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);

int sk_msg_free(struct sock *sk, struct sk_msg *msg)
{
	return __sk_msg_free(sk, msg, msg->sg.start, true);
}
EXPORT_SYMBOL_GPL(sk_msg_free);

static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
				  u32 bytes, bool charge)
{
	struct scatterlist *sge;
	u32 i = msg->sg.start;

	while (bytes) {
		sge = sk_msg_elem(msg, i);
		if (!sge->length)
			break;
		if (bytes < sge->length) {
			if (charge)
				sk_mem_uncharge(sk, bytes);
			sge->length -= bytes;
			sge->offset += bytes;
			msg->sg.size -= bytes;
			break;
		}

		msg->sg.size -= sge->length;
		bytes -= sge->length;
		sk_msg_free_elem(sk, msg, i, charge);
		sk_msg_iter_var_next(i);
		sk_msg_check_to_free(msg, i, bytes);
	}
	msg->sg.start = i;
}

void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
{
	__sk_msg_free_partial(sk, msg, bytes, true);
}
EXPORT_SYMBOL_GPL(sk_msg_free_partial);

void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
				  u32 bytes)
{
	__sk_msg_free_partial(sk, msg, bytes, false);
}

void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
{
	int trim = msg->sg.size - len;
	u32 i = msg->sg.end;

	if (trim <= 0) {
		WARN_ON(trim < 0);
		return;
	}

	sk_msg_iter_var_prev(i);
	msg->sg.size = len;
	while (msg->sg.data[i].length &&
	       trim >= msg->sg.data[i].length) {
		trim -= msg->sg.data[i].length;
		sk_msg_free_elem(sk, msg, i, true);
		sk_msg_iter_var_prev(i);
		if (!trim)
			goto out;
	}

	msg->sg.data[i].length -= trim;
	sk_mem_uncharge(sk, trim);
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	/* Adjust copybreak if it falls into the trimmed part of last buf */
	if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
		msg->sg.copybreak = msg->sg.data[i].length;
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out:
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	sk_msg_iter_var_next(i);
	msg->sg.end = i;

	/* If we trim data a full sg elem before curr pointer update
	 * copybreak and current so that any future copy operations
	 * start at new copy location.
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	 * However trimed data that has not yet been used in a copy op
	 * does not require an update.
	 */
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	if (!msg->sg.size) {
		msg->sg.curr = msg->sg.start;
		msg->sg.copybreak = 0;
	} else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
		   sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
		sk_msg_iter_var_prev(i);
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		msg->sg.curr = i;
		msg->sg.copybreak = msg->sg.data[i].length;
	}
}
EXPORT_SYMBOL_GPL(sk_msg_trim);

int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
			      struct sk_msg *msg, u32 bytes)
{
	int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
	const int to_max_pages = MAX_MSG_FRAGS;
	struct page *pages[MAX_MSG_FRAGS];
	ssize_t orig, copied, use, offset;

	orig = msg->sg.size;
	while (bytes > 0) {
		i = 0;
		maxpages = to_max_pages - num_elems;
		if (maxpages == 0) {
			ret = -EFAULT;
			goto out;
		}

		copied = iov_iter_get_pages(from, pages, bytes, maxpages,
					    &offset);
		if (copied <= 0) {
			ret = -EFAULT;
			goto out;
		}

		iov_iter_advance(from, copied);
		bytes -= copied;
		msg->sg.size += copied;

		while (copied) {
			use = min_t(int, copied, PAGE_SIZE - offset);
			sg_set_page(&msg->sg.data[msg->sg.end],
				    pages[i], use, offset);
			sg_unmark_end(&msg->sg.data[msg->sg.end]);
			sk_mem_charge(sk, use);

			offset = 0;
			copied -= use;
			sk_msg_iter_next(msg, end);
			num_elems++;
			i++;
		}
		/* When zerocopy is mixed with sk_msg_*copy* operations we
		 * may have a copybreak set in this case clear and prefer
		 * zerocopy remainder when possible.
		 */
		msg->sg.copybreak = 0;
		msg->sg.curr = msg->sg.end;
	}
out:
	/* Revert iov_iter updates, msg will need to use 'trim' later if it
	 * also needs to be cleared.
	 */
	if (ret)
		iov_iter_revert(from, msg->sg.size - orig);
	return ret;
}
EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);

int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
			     struct sk_msg *msg, u32 bytes)
{
	int ret = -ENOSPC, i = msg->sg.curr;
	struct scatterlist *sge;
	u32 copy, buf_size;
	void *to;

	do {
		sge = sk_msg_elem(msg, i);
		/* This is possible if a trim operation shrunk the buffer */
		if (msg->sg.copybreak >= sge->length) {
			msg->sg.copybreak = 0;
			sk_msg_iter_var_next(i);
			if (i == msg->sg.end)
				break;
			sge = sk_msg_elem(msg, i);
		}

		buf_size = sge->length - msg->sg.copybreak;
		copy = (buf_size > bytes) ? bytes : buf_size;
		to = sg_virt(sge) + msg->sg.copybreak;
		msg->sg.copybreak += copy;
		if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
			ret = copy_from_iter_nocache(to, copy, from);
		else
			ret = copy_from_iter(to, copy, from);
		if (ret != copy) {
			ret = -EFAULT;
			goto out;
		}
		bytes -= copy;
		if (!bytes)
			break;
		msg->sg.copybreak = 0;
		sk_msg_iter_var_next(i);
	} while (i != msg->sg.end);
out:
	msg->sg.curr = i;
	return ret;
}
EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);

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/* Receive sk_msg from psock->ingress_msg to @msg. */
int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
		   int len, int flags)
{
	struct iov_iter *iter = &msg->msg_iter;
	int peek = flags & MSG_PEEK;
	struct sk_msg *msg_rx;
	int i, copied = 0;

	msg_rx = sk_psock_peek_msg(psock);
	while (copied != len) {
		struct scatterlist *sge;

		if (unlikely(!msg_rx))
			break;

		i = msg_rx->sg.start;
		do {
			struct page *page;
			int copy;

			sge = sk_msg_elem(msg_rx, i);
			copy = sge->length;
			page = sg_page(sge);
			if (copied + copy > len)
				copy = len - copied;
			copy = copy_page_to_iter(page, sge->offset, copy, iter);
			if (!copy)
				return copied ? copied : -EFAULT;

			copied += copy;
			if (likely(!peek)) {
				sge->offset += copy;
				sge->length -= copy;
				if (!msg_rx->skb)
					sk_mem_uncharge(sk, copy);
				msg_rx->sg.size -= copy;

				if (!sge->length) {
					sk_msg_iter_var_next(i);
					if (!msg_rx->skb)
						put_page(page);
				}
			} else {
				/* Lets not optimize peek case if copy_page_to_iter
				 * didn't copy the entire length lets just break.
				 */
				if (copy != sge->length)
					return copied;
				sk_msg_iter_var_next(i);
			}

			if (copied == len)
				break;
		} while (i != msg_rx->sg.end);

		if (unlikely(peek)) {
			msg_rx = sk_psock_next_msg(psock, msg_rx);
			if (!msg_rx)
				break;
			continue;
		}

		msg_rx->sg.start = i;
		if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
			msg_rx = sk_psock_dequeue_msg(psock);
			kfree_sk_msg(msg_rx);
		}
		msg_rx = sk_psock_peek_msg(psock);
	}

	return copied;
}
EXPORT_SYMBOL_GPL(sk_msg_recvmsg);

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bool sk_msg_is_readable(struct sock *sk)
{
	struct sk_psock *psock;
	bool empty = true;

	rcu_read_lock();
	psock = sk_psock(sk);
	if (likely(psock))
		empty = list_empty(&psock->ingress_msg);
	rcu_read_unlock();
	return !empty;
}
EXPORT_SYMBOL_GPL(sk_msg_is_readable);

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static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
						  struct sk_buff *skb)
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{
	struct sk_msg *msg;

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	if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
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		return NULL;

	if (!sk_rmem_schedule(sk, skb, skb->truesize))
		return NULL;
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	msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_KERNEL);
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	if (unlikely(!msg))
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		return NULL;
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	sk_msg_init(msg);
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	return msg;
}

static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
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					u32 off, u32 len,
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					struct sk_psock *psock,
					struct sock *sk,
					struct sk_msg *msg)
{
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	int num_sge, copied;
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	num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
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	if (num_sge < 0) {
		/* skb linearize may fail with ENOMEM, but lets simply try again
		 * later if this happens. Under memory pressure we don't want to
		 * drop the skb. We need to linearize the skb so that the mapping
		 * in skb_to_sgvec can not error.
		 */
		if (skb_linearize(skb))
			return -EAGAIN;

		num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
		if (unlikely(num_sge < 0))
			return num_sge;
	}
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	copied = len;
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	msg->sg.start = 0;
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	msg->sg.size = copied;
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	msg->sg.end = num_sge;
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	msg->skb = skb;

	sk_psock_queue_msg(psock, msg);
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	sk_psock_data_ready(sk, psock);
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	return copied;
}

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static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
				     u32 off, u32 len);
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static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
				u32 off, u32 len)
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{
	struct sock *sk = psock->sk;
	struct sk_msg *msg;
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	int err;
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	/* If we are receiving on the same sock skb->sk is already assigned,
	 * skip memory accounting and owner transition seeing it already set
	 * correctly.
	 */
	if (unlikely(skb->sk == sk))
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		return sk_psock_skb_ingress_self(psock, skb, off, len);
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	msg = sk_psock_create_ingress_msg(sk, skb);
	if (!msg)
		return -EAGAIN;

	/* This will transition ownership of the data from the socket where
	 * the BPF program was run initiating the redirect to the socket
	 * we will eventually receive this data on. The data will be released
	 * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
	 * into user buffers.
	 */
	skb_set_owner_r(skb, sk);
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	err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
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	if (err < 0)
		kfree(msg);
	return err;
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}

/* Puts an skb on the ingress queue of the socket already assigned to the
 * skb. In this case we do not need to check memory limits or skb_set_owner_r
 * because the skb is already accounted for here.
 */
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static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
				     u32 off, u32 len)
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{
	struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
	struct sock *sk = psock->sk;
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	int err;
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	if (unlikely(!msg))
		return -EAGAIN;
	sk_msg_init(msg);
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	skb_set_owner_r(skb, sk);
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	err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
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	if (err < 0)
		kfree(msg);
	return err;
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}

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static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
			       u32 off, u32 len, bool ingress)
{
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	if (!ingress) {
		if (!sock_writeable(psock->sk))
			return -EAGAIN;
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		return skb_send_sock(psock->sk, skb, off, len);
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	}
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	return sk_psock_skb_ingress(psock, skb, off, len);
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}

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static void sk_psock_skb_state(struct sk_psock *psock,
			       struct sk_psock_work_state *state,
			       struct sk_buff *skb,
			       int len, int off)
{
	spin_lock_bh(&psock->ingress_lock);
	if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
		state->skb = skb;
		state->len = len;
		state->off = off;
	} else {
		sock_drop(psock->sk, skb);
	}
	spin_unlock_bh(&psock->ingress_lock);
}

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static void sk_psock_backlog(struct work_struct *work)
{
	struct sk_psock *psock = container_of(work, struct sk_psock, work);
	struct sk_psock_work_state *state = &psock->work_state;
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	struct sk_buff *skb = NULL;
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	bool ingress;
	u32 len, off;
	int ret;

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	mutex_lock(&psock->work_mutex);
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	if (unlikely(state->skb)) {
		spin_lock_bh(&psock->ingress_lock);
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		skb = state->skb;
		len = state->len;
		off = state->off;
		state->skb = NULL;
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		spin_unlock_bh(&psock->ingress_lock);
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	}
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	if (skb)
		goto start;
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	while ((skb = skb_dequeue(&psock->ingress_skb))) {
		len = skb->len;
		off = 0;
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		if (skb_bpf_strparser(skb)) {
			struct strp_msg *stm = strp_msg(skb);

			off = stm->offset;
			len = stm->full_len;
		}
664
start:
665 666
		ingress = skb_bpf_ingress(skb);
		skb_bpf_redirect_clear(skb);
667 668
		do {
			ret = -EIO;
669
			if (!sock_flag(psock->sk, SOCK_DEAD))
670 671 672 673
				ret = sk_psock_handle_skb(psock, skb, off,
							  len, ingress);
			if (ret <= 0) {
				if (ret == -EAGAIN) {
674 675
					sk_psock_skb_state(psock, state, skb,
							   len, off);
676 677 678 679 680
					goto end;
				}
				/* Hard errors break pipe and stop xmit. */
				sk_psock_report_error(psock, ret ? -ret : EPIPE);
				sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
681
				sock_drop(psock->sk, skb);
682 683 684 685 686 687 688 689 690 691
				goto end;
			}
			off += ret;
			len -= ret;
		} while (len);

		if (!ingress)
			kfree_skb(skb);
	}
end:
692
	mutex_unlock(&psock->work_mutex);
693 694 695 696
}

struct sk_psock *sk_psock_init(struct sock *sk, int node)
{
697 698
	struct sk_psock *psock;
	struct proto *prot;
699

700 701 702 703 704 705 706 707 708 709 710 711 712 713
	write_lock_bh(&sk->sk_callback_lock);

	if (sk->sk_user_data) {
		psock = ERR_PTR(-EBUSY);
		goto out;
	}

	psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
	if (!psock) {
		psock = ERR_PTR(-ENOMEM);
		goto out;
	}

	prot = READ_ONCE(sk->sk_prot);
714
	psock->sk = sk;
715 716 717
	psock->eval = __SK_NONE;
	psock->sk_proto = prot;
	psock->saved_unhash = prot->unhash;
718
	psock->saved_destroy = prot->destroy;
719 720
	psock->saved_close = prot->close;
	psock->saved_write_space = sk->sk_write_space;
721 722 723 724 725

	INIT_LIST_HEAD(&psock->link);
	spin_lock_init(&psock->link_lock);

	INIT_WORK(&psock->work, sk_psock_backlog);
726
	mutex_init(&psock->work_mutex);
727
	INIT_LIST_HEAD(&psock->ingress_msg);
728
	spin_lock_init(&psock->ingress_lock);
729 730 731 732 733
	skb_queue_head_init(&psock->ingress_skb);

	sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
	refcount_set(&psock->refcnt, 1);

734
	rcu_assign_sk_user_data_nocopy(sk, psock);
735 736
	sock_hold(sk);

737 738
out:
	write_unlock_bh(&sk->sk_callback_lock);
739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755
	return psock;
}
EXPORT_SYMBOL_GPL(sk_psock_init);

struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
{
	struct sk_psock_link *link;

	spin_lock_bh(&psock->link_lock);
	link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
					list);
	if (link)
		list_del(&link->list);
	spin_unlock_bh(&psock->link_lock);
	return link;
}

756
static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
757 758 759 760 761 762 763 764 765 766
{
	struct sk_msg *msg, *tmp;

	list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
		list_del(&msg->list);
		sk_msg_free(psock->sk, msg);
		kfree(msg);
	}
}

767
static void __sk_psock_zap_ingress(struct sk_psock *psock)
768
{
769 770
	struct sk_buff *skb;

771
	while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
772
		skb_bpf_redirect_clear(skb);
773
		sock_drop(psock->sk, skb);
774
	}
775 776 777 778 779
	kfree_skb(psock->work_state.skb);
	/* We null the skb here to ensure that calls to sk_psock_backlog
	 * do not pick up the free'd skb.
	 */
	psock->work_state.skb = NULL;
780 781 782 783 784 785 786 787 788 789 790 791 792
	__sk_psock_purge_ingress_msg(psock);
}

static void sk_psock_link_destroy(struct sk_psock *psock)
{
	struct sk_psock_link *link, *tmp;

	list_for_each_entry_safe(link, tmp, &psock->link, list) {
		list_del(&link->list);
		sk_psock_free_link(link);
	}
}

793 794 795 796 797 798 799 800 801 802 803 804
void sk_psock_stop(struct sk_psock *psock, bool wait)
{
	spin_lock_bh(&psock->ingress_lock);
	sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
	sk_psock_cork_free(psock);
	__sk_psock_zap_ingress(psock);
	spin_unlock_bh(&psock->ingress_lock);

	if (wait)
		cancel_work_sync(&psock->work);
}

805 806
static void sk_psock_done_strp(struct sk_psock *psock);

807
static void sk_psock_destroy(struct work_struct *work)
808
{
809 810
	struct sk_psock *psock = container_of(to_rcu_work(work),
					      struct sk_psock, rwork);
811
	/* No sk_callback_lock since already detached. */
812

813
	sk_psock_done_strp(psock);
814 815

	cancel_work_sync(&psock->work);
816
	mutex_destroy(&psock->work_mutex);
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831

	psock_progs_drop(&psock->progs);

	sk_psock_link_destroy(psock);
	sk_psock_cork_free(psock);

	if (psock->sk_redir)
		sock_put(psock->sk_redir);
	sock_put(psock->sk);
	kfree(psock);
}

void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
{
	write_lock_bh(&sk->sk_callback_lock);
832 833
	sk_psock_restore_proto(sk, psock);
	rcu_assign_sk_user_data(sk, NULL);
834
	if (psock->progs.stream_parser)
835
		sk_psock_stop_strp(sk, psock);
836
	else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
837
		sk_psock_stop_verdict(sk, psock);
838 839
	write_unlock_bh(&sk->sk_callback_lock);

840 841
	sk_psock_stop(psock, false);

842 843
	INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
	queue_rcu_work(system_wq, &psock->rwork);
844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874
}
EXPORT_SYMBOL_GPL(sk_psock_drop);

static int sk_psock_map_verd(int verdict, bool redir)
{
	switch (verdict) {
	case SK_PASS:
		return redir ? __SK_REDIRECT : __SK_PASS;
	case SK_DROP:
	default:
		break;
	}

	return __SK_DROP;
}

int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
			 struct sk_msg *msg)
{
	struct bpf_prog *prog;
	int ret;

	rcu_read_lock();
	prog = READ_ONCE(psock->progs.msg_parser);
	if (unlikely(!prog)) {
		ret = __SK_PASS;
		goto out;
	}

	sk_msg_compute_data_pointers(msg);
	msg->sk = sk;
875
	ret = bpf_prog_run_pin_on_cpu(prog, msg);
876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893
	ret = sk_psock_map_verd(ret, msg->sk_redir);
	psock->apply_bytes = msg->apply_bytes;
	if (ret == __SK_REDIRECT) {
		if (psock->sk_redir)
			sock_put(psock->sk_redir);
		psock->sk_redir = msg->sk_redir;
		if (!psock->sk_redir) {
			ret = __SK_DROP;
			goto out;
		}
		sock_hold(psock->sk_redir);
	}
out:
	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);

894
static int sk_psock_skb_redirect(struct sk_psock *from, struct sk_buff *skb)
895 896 897 898
{
	struct sk_psock *psock_other;
	struct sock *sk_other;

899
	sk_other = skb_bpf_redirect_fetch(skb);
900 901 902
	/* This error is a buggy BPF program, it returned a redirect
	 * return code, but then didn't set a redirect interface.
	 */
903
	if (unlikely(!sk_other)) {
904
		skb_bpf_redirect_clear(skb);
905
		sock_drop(from->sk, skb);
906
		return -EIO;
907 908
	}
	psock_other = sk_psock(sk_other);
909 910 911 912
	/* This error indicates the socket is being torn down or had another
	 * error that caused the pipe to break. We can't send a packet on
	 * a socket that is in this state so we drop the skb.
	 */
913
	if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
914
		skb_bpf_redirect_clear(skb);
915
		sock_drop(from->sk, skb);
916
		return -EIO;
917 918 919 920
	}
	spin_lock_bh(&psock_other->ingress_lock);
	if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
		spin_unlock_bh(&psock_other->ingress_lock);
921
		skb_bpf_redirect_clear(skb);
922
		sock_drop(from->sk, skb);
923
		return -EIO;
924 925
	}

926 927
	skb_queue_tail(&psock_other->ingress_skb, skb);
	schedule_work(&psock_other->work);
928
	spin_unlock_bh(&psock_other->ingress_lock);
929
	return 0;
930 931
}

932 933
static void sk_psock_tls_verdict_apply(struct sk_buff *skb,
				       struct sk_psock *from, int verdict)
934 935 936
{
	switch (verdict) {
	case __SK_REDIRECT:
937
		sk_psock_skb_redirect(from, skb);
938 939 940 941 942 943 944 945 946 947 948 949 950 951
		break;
	case __SK_PASS:
	case __SK_DROP:
	default:
		break;
	}
}

int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
{
	struct bpf_prog *prog;
	int ret = __SK_PASS;

	rcu_read_lock();
952
	prog = READ_ONCE(psock->progs.stream_verdict);
953
	if (likely(prog)) {
954
		skb->sk = psock->sk;
955 956
		skb_dst_drop(skb);
		skb_bpf_redirect_clear(skb);
957
		ret = bpf_prog_run_pin_on_cpu(prog, skb);
958
		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
959
		skb->sk = NULL;
960
	}
961
	sk_psock_tls_verdict_apply(skb, psock, ret);
962 963 964 965 966
	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);

967 968
static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
				  int verdict)
969 970
{
	struct sock *sk_other;
971
	int err = 0;
972
	u32 len, off;
973

974
	switch (verdict) {
975
	case __SK_PASS:
976
		err = -EIO;
977 978 979
		sk_other = psock->sk;
		if (sock_flag(sk_other, SOCK_DEAD) ||
		    !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
980
			skb_bpf_redirect_clear(skb);
981 982 983
			goto out_free;
		}

984
		skb_bpf_set_ingress(skb);
985 986 987 988 989 990 991 992

		/* If the queue is empty then we can submit directly
		 * into the msg queue. If its not empty we have to
		 * queue work otherwise we may get OOO data. Otherwise,
		 * if sk_psock_skb_ingress errors will be handled by
		 * retrying later from workqueue.
		 */
		if (skb_queue_empty(&psock->ingress_skb)) {
993 994 995 996 997 998 999 1000 1001
			len = skb->len;
			off = 0;
			if (skb_bpf_strparser(skb)) {
				struct strp_msg *stm = strp_msg(skb);

				off = stm->offset;
				len = stm->full_len;
			}
			err = sk_psock_skb_ingress_self(psock, skb, off, len);
1002 1003
		}
		if (err < 0) {
1004 1005 1006 1007
			spin_lock_bh(&psock->ingress_lock);
			if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
				skb_queue_tail(&psock->ingress_skb, skb);
				schedule_work(&psock->work);
1008
				err = 0;
1009 1010
			}
			spin_unlock_bh(&psock->ingress_lock);
1011 1012 1013 1014
			if (err < 0) {
				skb_bpf_redirect_clear(skb);
				goto out_free;
			}
1015
		}
1016
		break;
1017
	case __SK_REDIRECT:
1018
		err = sk_psock_skb_redirect(psock, skb);
1019
		break;
1020 1021 1022
	case __SK_DROP:
	default:
out_free:
1023
		sock_drop(psock->sk, skb);
1024
	}
1025 1026

	return err;
1027 1028
}

1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
static void sk_psock_write_space(struct sock *sk)
{
	struct sk_psock *psock;
	void (*write_space)(struct sock *sk) = NULL;

	rcu_read_lock();
	psock = sk_psock(sk);
	if (likely(psock)) {
		if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
			schedule_work(&psock->work);
		write_space = psock->saved_write_space;
	}
	rcu_read_unlock();
	if (write_space)
		write_space(sk);
}

#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1047 1048
static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
{
1049
	struct sk_psock *psock;
1050 1051
	struct bpf_prog *prog;
	int ret = __SK_DROP;
1052
	struct sock *sk;
1053 1054

	rcu_read_lock();
1055 1056 1057
	sk = strp->sk;
	psock = sk_psock(sk);
	if (unlikely(!psock)) {
1058
		sock_drop(sk, skb);
1059 1060
		goto out;
	}
1061
	prog = READ_ONCE(psock->progs.stream_verdict);
1062
	if (likely(prog)) {
1063
		skb->sk = sk;
1064 1065
		skb_dst_drop(skb);
		skb_bpf_redirect_clear(skb);
1066
		ret = bpf_prog_run_pin_on_cpu(prog, skb);
1067 1068
		if (ret == SK_PASS)
			skb_bpf_set_strparser(skb);
1069
		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1070
		skb->sk = NULL;
1071 1072
	}
	sk_psock_verdict_apply(psock, skb, ret);
1073
out:
1074
	rcu_read_unlock();
1075 1076 1077 1078 1079 1080 1081 1082 1083
}

static int sk_psock_strp_read_done(struct strparser *strp, int err)
{
	return err;
}

static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
{
1084
	struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1085 1086 1087 1088
	struct bpf_prog *prog;
	int ret = skb->len;

	rcu_read_lock();
1089
	prog = READ_ONCE(psock->progs.stream_parser);
1090 1091
	if (likely(prog)) {
		skb->sk = psock->sk;
1092
		ret = bpf_prog_run_pin_on_cpu(prog, skb);
1093 1094
		skb->sk = NULL;
	}
1095 1096 1097 1098 1099
	rcu_read_unlock();
	return ret;
}

/* Called with socket lock held. */
1100
static void sk_psock_strp_data_ready(struct sock *sk)
1101 1102 1103 1104 1105 1106
{
	struct sk_psock *psock;

	rcu_read_lock();
	psock = sk_psock(sk);
	if (likely(psock)) {
1107
		if (tls_sw_has_ctx_rx(sk)) {
1108
			psock->saved_data_ready(sk);
1109 1110
		} else {
			write_lock_bh(&sk->sk_callback_lock);
1111
			strp_data_ready(&psock->strp);
1112 1113
			write_unlock_bh(&sk->sk_callback_lock);
		}
1114 1115 1116 1117
	}
	rcu_read_unlock();
}

1118 1119 1120 1121 1122 1123 1124 1125
int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
{
	static const struct strp_callbacks cb = {
		.rcv_msg	= sk_psock_strp_read,
		.read_sock_done	= sk_psock_strp_read_done,
		.parse_msg	= sk_psock_strp_parse,
	};

1126
	return strp_init(&psock->strp, sk, &cb);
1127 1128 1129 1130
}

void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
{
1131
	if (psock->saved_data_ready)
1132 1133
		return;

1134
	psock->saved_data_ready = sk->sk_data_ready;
1135 1136 1137 1138 1139 1140
	sk->sk_data_ready = sk_psock_strp_data_ready;
	sk->sk_write_space = sk_psock_write_space;
}

void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
{
1141 1142
	psock_set_prog(&psock->progs.stream_parser, NULL);

1143
	if (!psock->saved_data_ready)
1144 1145
		return;

1146 1147 1148
	sk->sk_data_ready = psock->saved_data_ready;
	psock->saved_data_ready = NULL;
	strp_stop(&psock->strp);
1149 1150 1151 1152 1153
}

static void sk_psock_done_strp(struct sk_psock *psock)
{
	/* Parser has been stopped */
1154
	if (psock->progs.stream_parser)
1155
		strp_done(&psock->strp);
1156 1157 1158 1159 1160 1161 1162
}
#else
static void sk_psock_done_strp(struct sk_psock *psock)
{
}
#endif /* CONFIG_BPF_STREAM_PARSER */

1163
static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
1164 1165 1166 1167
{
	struct sk_psock *psock;
	struct bpf_prog *prog;
	int ret = __SK_DROP;
1168
	int len = skb->len;
1169 1170 1171

	/* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */
	skb = skb_clone(skb, GFP_ATOMIC);
1172
	if (!skb)
1173 1174 1175 1176 1177 1178
		return 0;

	rcu_read_lock();
	psock = sk_psock(sk);
	if (unlikely(!psock)) {
		len = 0;
1179
		sock_drop(sk, skb);
1180 1181
		goto out;
	}
1182
	prog = READ_ONCE(psock->progs.stream_verdict);
1183 1184
	if (!prog)
		prog = READ_ONCE(psock->progs.skb_verdict);
1185
	if (likely(prog)) {
1186
		skb->sk = sk;
1187 1188
		skb_dst_drop(skb);
		skb_bpf_redirect_clear(skb);
1189
		ret = bpf_prog_run_pin_on_cpu(prog, skb);
1190
		ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1191
		skb->sk = NULL;
1192
	}
1193 1194
	if (sk_psock_verdict_apply(psock, skb, ret) < 0)
		len = 0;
1195 1196 1197 1198 1199 1200 1201 1202 1203
out:
	rcu_read_unlock();
	return len;
}

static void sk_psock_verdict_data_ready(struct sock *sk)
{
	struct socket *sock = sk->sk_socket;

1204
	if (unlikely(!sock || !sock->ops || !sock->ops->read_skb))
1205
		return;
1206
	sock->ops->read_skb(sk, sk_psock_verdict_recv);
1207 1208 1209 1210
}

void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
{
1211
	if (psock->saved_data_ready)
1212 1213
		return;

1214
	psock->saved_data_ready = sk->sk_data_ready;
1215 1216 1217 1218 1219 1220
	sk->sk_data_ready = sk_psock_verdict_data_ready;
	sk->sk_write_space = sk_psock_write_space;
}

void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
{
1221 1222 1223
	psock_set_prog(&psock->progs.stream_verdict, NULL);
	psock_set_prog(&psock->progs.skb_verdict, NULL);

1224
	if (!psock->saved_data_ready)
1225 1226
		return;

1227 1228
	sk->sk_data_ready = psock->saved_data_ready;
	psock->saved_data_ready = NULL;
1229
}