1 files changed, 763 insertions, 0 deletions

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
new file mode 100644
index 000000000000..ae2b281c9c57
--- /dev/null
+++ b/net/core/skmsg.c
@@ -0,0 +1,763 @@
+// 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>
+
+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);
+	int ret = 0;
+
+	len -= msg->sg.size;
+	while (len > 0) {
+		struct scatterlist *sge;
+		u32 orig_offset;
+		int use, i;
+
+		if (!sk_page_frag_refill(sk, pfrag))
+			return -ENOMEM;
+
+		orig_offset = pfrag->offset;
+		use = min_t(int, len, pfrag->size - orig_offset);
+		if (!sk_wmem_schedule(sk, use))
+			return -ENOMEM;
+
+		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;
+}
+EXPORT_SYMBOL_GPL(sk_msg_alloc);
+
+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;
+
+	if (charge)
+		sk_mem_uncharge(sk, len);
+	if (!msg->skb)
+		put_page(sg_page(sge));
+	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);
+	}
+	if (msg->skb)
+		consume_skb(msg->skb);
+	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);
+out:
+	/* If we trim data before curr pointer update copybreak and current
+	 * so that any future copy operations start at new copy location.
+	 * However trimed data that has not yet been used in a copy op
+	 * does not require an update.
+	 */
+	if (msg->sg.curr >= i) {
+		msg->sg.curr = i;
+		msg->sg.copybreak = msg->sg.data[i].length;
+	}
+	sk_msg_iter_var_next(i);
+	msg->sg.end = i;
+}
+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);
+
+static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
+{
+	struct sock *sk = psock->sk;
+	int copied = 0, num_sge;
+	struct sk_msg *msg;
+
+	msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
+	if (unlikely(!msg))
+		return -EAGAIN;
+	if (!sk_rmem_schedule(sk, skb, skb->len)) {
+		kfree(msg);
+		return -EAGAIN;
+	}
+
+	sk_msg_init(msg);
+	num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
+	if (unlikely(num_sge < 0)) {
+		kfree(msg);
+		return num_sge;
+	}
+
+	sk_mem_charge(sk, skb->len);
+	copied = skb->len;
+	msg->sg.start = 0;
+	msg->sg.end = num_sge == MAX_MSG_FRAGS ? 0 : num_sge;
+	msg->skb = skb;
+
+	sk_psock_queue_msg(psock, msg);
+	sk->sk_data_ready(sk);
+	return copied;
+}
+
+static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
+			       u32 off, u32 len, bool ingress)
+{
+	if (ingress)
+		return sk_psock_skb_ingress(psock, skb);
+	else
+		return skb_send_sock_locked(psock->sk, skb, off, len);
+}
+
+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;
+	struct sk_buff *skb;
+	bool ingress;
+	u32 len, off;
+	int ret;
+
+	/* Lock sock to avoid losing sk_socket during loop. */
+	lock_sock(psock->sk);
+	if (state->skb) {
+		skb = state->skb;
+		len = state->len;
+		off = state->off;
+		state->skb = NULL;
+		goto start;
+	}
+
+	while ((skb = skb_dequeue(&psock->ingress_skb))) {
+		len = skb->len;
+		off = 0;
+start:
+		ingress = tcp_skb_bpf_ingress(skb);
+		do {
+			ret = -EIO;
+			if (likely(psock->sk->sk_socket))
+				ret = sk_psock_handle_skb(psock, skb, off,
+							  len, ingress);
+			if (ret <= 0) {
+				if (ret == -EAGAIN) {
+					state->skb = skb;
+					state->len = len;
+					state->off = off;
+					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);
+				kfree_skb(skb);
+				goto end;
+			}
+			off += ret;
+			len -= ret;
+		} while (len);
+
+		if (!ingress)
+			kfree_skb(skb);
+	}
+end:
+	release_sock(psock->sk);
+}
+
+struct sk_psock *sk_psock_init(struct sock *sk, int node)
+{
+	struct sk_psock *psock = kzalloc_node(sizeof(*psock),
+					      GFP_ATOMIC | __GFP_NOWARN,
+					      node);
+	if (!psock)
+		return NULL;
+
+	psock->sk = sk;
+	psock->eval =  __SK_NONE;
+
+	INIT_LIST_HEAD(&psock->link);
+	spin_lock_init(&psock->link_lock);
+
+	INIT_WORK(&psock->work, sk_psock_backlog);
+	INIT_LIST_HEAD(&psock->ingress_msg);
+	skb_queue_head_init(&psock->ingress_skb);
+
+	sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
+	refcount_set(&psock->refcnt, 1);
+
+	rcu_assign_sk_user_data(sk, psock);
+	sock_hold(sk);
+
+	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;
+}
+
+void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
+{
+	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);
+	}
+}
+
+static void sk_psock_zap_ingress(struct sk_psock *psock)
+{
+	__skb_queue_purge(&psock->ingress_skb);
+	__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);
+	}
+}
+
+static void sk_psock_destroy_deferred(struct work_struct *gc)
+{
+	struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
+
+	/* No sk_callback_lock since already detached. */
+	if (psock->parser.enabled)
+		strp_done(&psock->parser.strp);
+
+	cancel_work_sync(&psock->work);
+
+	psock_progs_drop(&psock->progs);
+
+	sk_psock_link_destroy(psock);
+	sk_psock_cork_free(psock);
+	sk_psock_zap_ingress(psock);
+
+	if (psock->sk_redir)
+		sock_put(psock->sk_redir);
+	sock_put(psock->sk);
+	kfree(psock);
+}
+
+void sk_psock_destroy(struct rcu_head *rcu)
+{
+	struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
+
+	INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
+	schedule_work(&psock->gc);
+}
+EXPORT_SYMBOL_GPL(sk_psock_destroy);
+
+void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
+{
+	rcu_assign_sk_user_data(sk, NULL);
+	sk_psock_cork_free(psock);
+	sk_psock_restore_proto(sk, psock);
+
+	write_lock_bh(&sk->sk_callback_lock);
+	if (psock->progs.skb_parser)
+		sk_psock_stop_strp(sk, psock);
+	write_unlock_bh(&sk->sk_callback_lock);
+	sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
+
+	call_rcu_sched(&psock->rcu, sk_psock_destroy);
+}
+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;
+
+	preempt_disable();
+	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;
+	ret = BPF_PROG_RUN(prog, msg);
+	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();
+	preempt_enable();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
+
+static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
+			    struct sk_buff *skb)
+{
+	int ret;
+
+	skb->sk = psock->sk;
+	bpf_compute_data_end_sk_skb(skb);
+	preempt_disable();
+	ret = BPF_PROG_RUN(prog, skb);
+	preempt_enable();
+	/* strparser clones the skb before handing it to a upper layer,
+	 * meaning skb_orphan has been called. We NULL sk on the way out
+	 * to ensure we don't trigger a BUG_ON() in skb/sk operations
+	 * later and because we are not charging the memory of this skb
+	 * to any socket yet.
+	 */
+	skb->sk = NULL;
+	return ret;
+}
+
+static struct sk_psock *sk_psock_from_strp(struct strparser *strp)
+{
+	struct sk_psock_parser *parser;
+
+	parser = container_of(strp, struct sk_psock_parser, strp);
+	return container_of(parser, struct sk_psock, parser);
+}
+
+static void sk_psock_verdict_apply(struct sk_psock *psock,
+				   struct sk_buff *skb, int verdict)
+{
+	struct sk_psock *psock_other;
+	struct sock *sk_other;
+	bool ingress;
+
+	switch (verdict) {
+	case __SK_REDIRECT:
+		sk_other = tcp_skb_bpf_redirect_fetch(skb);
+		if (unlikely(!sk_other))
+			goto out_free;
+		psock_other = sk_psock(sk_other);
+		if (!psock_other || sock_flag(sk_other, SOCK_DEAD) ||
+		    !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED))
+			goto out_free;
+		ingress = tcp_skb_bpf_ingress(skb);
+		if ((!ingress && sock_writeable(sk_other)) ||
+		    (ingress &&
+		     atomic_read(&sk_other->sk_rmem_alloc) <=
+		     sk_other->sk_rcvbuf)) {
+			if (!ingress)
+				skb_set_owner_w(skb, sk_other);
+			skb_queue_tail(&psock_other->ingress_skb, skb);
+			schedule_work(&psock_other->work);
+			break;
+		}
+		/* fall-through */
+	case __SK_DROP:
+		/* fall-through */
+	default:
+out_free:
+		kfree_skb(skb);
+	}
+}
+
+static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
+{
+	struct sk_psock *psock = sk_psock_from_strp(strp);
+	struct bpf_prog *prog;
+	int ret = __SK_DROP;
+
+	rcu_read_lock();
+	prog = READ_ONCE(psock->progs.skb_verdict);
+	if (likely(prog)) {
+		skb_orphan(skb);
+		tcp_skb_bpf_redirect_clear(skb);
+		ret = sk_psock_bpf_run(psock, prog, skb);
+		ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
+	}
+	rcu_read_unlock();
+	sk_psock_verdict_apply(psock, skb, ret);
+}
+
+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)
+{
+	struct sk_psock *psock = sk_psock_from_strp(strp);
+	struct bpf_prog *prog;
+	int ret = skb->len;
+
+	rcu_read_lock();
+	prog = READ_ONCE(psock->progs.skb_parser);
+	if (likely(prog))
+		ret = sk_psock_bpf_run(psock, prog, skb);
+	rcu_read_unlock();
+	return ret;
+}
+
+/* Called with socket lock held. */
+static void sk_psock_data_ready(struct sock *sk)
+{
+	struct sk_psock *psock;
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (likely(psock)) {
+		write_lock_bh(&sk->sk_callback_lock);
+		strp_data_ready(&psock->parser.strp);
+		write_unlock_bh(&sk->sk_callback_lock);
+	}
+	rcu_read_unlock();
+}
+
+static void sk_psock_write_space(struct sock *sk)
+{
+	struct sk_psock *psock;
+	void (*write_space)(struct sock *sk);
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)))
+		schedule_work(&psock->work);
+	write_space = psock->saved_write_space;
+	rcu_read_unlock();
+	write_space(sk);
+}
+
+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,
+	};
+
+	psock->parser.enabled = false;
+	return strp_init(&psock->parser.strp, sk, &cb);
+}
+
+void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
+{
+	struct sk_psock_parser *parser = &psock->parser;
+
+	if (parser->enabled)
+		return;
+
+	parser->saved_data_ready = sk->sk_data_ready;
+	sk->sk_data_ready = sk_psock_data_ready;
+	sk->sk_write_space = sk_psock_write_space;
+	parser->enabled = true;
+}
+
+void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
+{
+	struct sk_psock_parser *parser = &psock->parser;
+
+	if (!parser->enabled)
+		return;
+
+	sk->sk_data_ready = parser->saved_data_ready;
+	parser->saved_data_ready = NULL;
+	strp_stop(&parser->strp);
+	parser->enabled = false;
+}