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Commit 66f87790 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'udp-peek' 



Willem de Bruijn says:

====================
udp: support SO_PEEK_OFF

Support peeking at a non-zero offset for UDP sockets. Match the
existing behavior on Unix datagram sockets.

1/3 makes the sk_peek_offset functions safe to use outside locks
2/3 removes udp headers before enqueue, to simplify offset arithmetic
3/3 introduces SO_PEEK_OFFSET support, with Unix socket peek semantics.

Changes
  v1->v2
    - squash patches 3 and 4
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents e43d15c8 627d2d6b

include/linux/skbuff.h

+6 −1
Original line number Diff line number Diff line
@@ -2949,7 +2949,12 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset, 
				 struct iov_iter *from, int len);

int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);

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

void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);

void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len);

static inline void skb_free_datagram_locked(struct sock *sk,

					    struct sk_buff *skb)

{

	__skb_free_datagram_locked(sk, skb, 0);

}

int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);

int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);

int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);

include/net/sock.h

+16 −11
Original line number Diff line number Diff line
@@ -457,28 +457,32 @@ struct sock { 
#define SK_CAN_REUSE	1

#define SK_FORCE_REUSE	2



int sk_set_peek_off(struct sock *sk, int val);



static inline int sk_peek_offset(struct sock *sk, int flags)

{

	if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))

		return sk->sk_peek_off;

	else

	if (unlikely(flags & MSG_PEEK)) {

		s32 off = READ_ONCE(sk->sk_peek_off);

		if (off >= 0)

			return off;

	}



	return 0;

}



static inline void sk_peek_offset_bwd(struct sock *sk, int val)

{

	if (sk->sk_peek_off >= 0) {

		if (sk->sk_peek_off >= val)

			sk->sk_peek_off -= val;

		else

			sk->sk_peek_off = 0;

	s32 off = READ_ONCE(sk->sk_peek_off);



	if (unlikely(off >= 0)) {

		off = max_t(s32, off - val, 0);

		WRITE_ONCE(sk->sk_peek_off, off);

	}

}



static inline void sk_peek_offset_fwd(struct sock *sk, int val)

{

	if (sk->sk_peek_off >= 0)

		sk->sk_peek_off += val;

	sk_peek_offset_bwd(sk, -val);

}



/*
@@ -1862,6 +1866,7 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer, 


void sk_stop_timer(struct sock *sk, struct timer_list *timer);



int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);

int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);



int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);

include/net/udp.h

+9 −0
Original line number Diff line number Diff line
@@ -158,6 +158,15 @@ static inline __sum16 udp_v4_check(int len, __be32 saddr, 
void udp_set_csum(bool nocheck, struct sk_buff *skb,

		  __be32 saddr, __be32 daddr, int len);



static inline void udp_csum_pull_header(struct sk_buff *skb)

{

	if (skb->ip_summed == CHECKSUM_NONE)

		skb->csum = csum_partial(udp_hdr(skb), sizeof(struct udphdr),

					 skb->csum);

	skb_pull_rcsum(skb, sizeof(struct udphdr));

	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);

}



struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,

				 struct udphdr *uh);

int udp_gro_complete(struct sk_buff *skb, int nhoff);

net/core/datagram.c

+6 −3
Original line number Diff line number Diff line
@@ -301,16 +301,19 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb) 
}

EXPORT_SYMBOL(skb_free_datagram);



void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb)

void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len)

{

	bool slow;



	if (likely(atomic_read(&skb->users) == 1))

		smp_rmb();

	else if (likely(!atomic_dec_and_test(&skb->users)))

	else if (likely(!atomic_dec_and_test(&skb->users))) {

		sk_peek_offset_bwd(sk, len);

		return;

	}



	slow = lock_sock_fast(sk);

	sk_peek_offset_bwd(sk, len);

	skb_orphan(skb);

	sk_mem_reclaim_partial(sk);

	unlock_sock_fast(sk, slow);
@@ -318,7 +321,7 @@ void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) 
	/* skb is now orphaned, can be freed outside of locked section */

	__kfree_skb(skb);

}

EXPORT_SYMBOL(skb_free_datagram_locked);

EXPORT_SYMBOL(__skb_free_datagram_locked);



/**

 *	skb_kill_datagram - Free a datagram skbuff forcibly

net/core/sock.c

+22 −6
Original line number Diff line number Diff line
@@ -402,9 +402,8 @@ static void sock_disable_timestamp(struct sock *sk, unsigned long flags) 
}





int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)

int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)

{

	int err;

	unsigned long flags;

	struct sk_buff_head *list = &sk->sk_receive_queue;
@@ -414,10 +413,6 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 
		return -ENOMEM;

	}



	err = sk_filter(sk, skb);

	if (err)

		return err;



	if (!sk_rmem_schedule(sk, skb, skb->truesize)) {

		atomic_inc(&sk->sk_drops);

		return -ENOBUFS;
@@ -440,6 +435,18 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 
		sk->sk_data_ready(sk);

	return 0;

}

EXPORT_SYMBOL(__sock_queue_rcv_skb);



int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)

{

	int err;



	err = sk_filter(sk, skb);

	if (err)

		return err;



	return __sock_queue_rcv_skb(sk, skb);

}

EXPORT_SYMBOL(sock_queue_rcv_skb);



int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested)
@@ -2180,6 +2187,15 @@ void __sk_mem_reclaim(struct sock *sk, int amount) 
}

EXPORT_SYMBOL(__sk_mem_reclaim);



int sk_set_peek_off(struct sock *sk, int val)

{

	if (val < 0)

		return -EINVAL;



	sk->sk_peek_off = val;

	return 0;

}

EXPORT_SYMBOL_GPL(sk_set_peek_off);



/*

 * Set of default routines for initialising struct proto_ops when