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Commit 5110effe authored by David S. Miller's avatar David S. Miller
Browse files

net: Do delayed neigh confirmation. 



When a dst_confirm() happens, mark the confirmation as pending in the
dst.  Then on the next packet out, when we have the neigh in-hand, do
the update.

This removes the dependency in dst_confirm() of dst's having an
attached neigh.

While we're here, remove the explicit 'dst' NULL check, all except 2
or 3 call sites ensure it's not NULL.  So just fix those cases up.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 60d354eb

include/net/dst.h

+21 −8
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ struct dst_entry { 
	int			(*input)(struct sk_buff *);

	int			(*output)(struct sk_buff *);



	int			flags;

	unsigned short		flags;

#define DST_HOST		0x0001

#define DST_NOXFRM		0x0002

#define DST_NOPOLICY		0x0004
@@ -62,6 +62,8 @@ struct dst_entry { 
#define DST_FAKE_RTABLE		0x0080

#define DST_XFRM_TUNNEL		0x0100



	unsigned short		pending_confirm;



	short			error;

	short			obsolete;

	unsigned short		header_len;	/* more space at head required */
@@ -371,7 +373,8 @@ static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb) 


extern int dst_discard(struct sk_buff *skb);

extern void *dst_alloc(struct dst_ops *ops, struct net_device *dev,

		       int initial_ref, int initial_obsolete, int flags);

		       int initial_ref, int initial_obsolete,

		       unsigned short flags);

extern void __dst_free(struct dst_entry *dst);

extern struct dst_entry *dst_destroy(struct dst_entry *dst);
@@ -395,14 +398,24 @@ static inline void dst_rcu_free(struct rcu_head *head) 


static inline void dst_confirm(struct dst_entry *dst)

{

	if (dst) {

		struct neighbour *n;

	dst->pending_confirm = 1;

}



		rcu_read_lock();

		n = dst_get_neighbour_noref(dst);

		neigh_confirm(n);

		rcu_read_unlock();

static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,

				   struct sk_buff *skb)

{

	struct hh_cache *hh;



	if (unlikely(dst->pending_confirm)) {

		n->confirmed = jiffies;

		dst->pending_confirm = 0;

	}



	hh = &n->hh;

	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)

		return neigh_hh_output(hh, skb);

	else

		return n->output(n, skb);

}



static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)

include/net/neighbour.h

+0 −15
Original line number Diff line number Diff line
@@ -309,12 +309,6 @@ static inline struct neighbour * neigh_clone(struct neighbour *neigh) 


#define neigh_hold(n)	atomic_inc(&(n)->refcnt)



static inline void neigh_confirm(struct neighbour *neigh)

{

	if (neigh)

		neigh->confirmed = jiffies;

}



static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)

{

	unsigned long now = jiffies;
@@ -358,15 +352,6 @@ static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb) 
	return dev_queue_xmit(skb);

}



static inline int neigh_output(struct neighbour *n, struct sk_buff *skb)

{

	struct hh_cache *hh = &n->hh;

	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)

		return neigh_hh_output(hh, skb);

	else

		return n->output(n, skb);

}



static inline struct neighbour *

__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)

{

net/core/dst.c

+2 −1
Original line number Diff line number Diff line
@@ -152,7 +152,7 @@ EXPORT_SYMBOL(dst_discard); 
const u32 dst_default_metrics[RTAX_MAX];



void *dst_alloc(struct dst_ops *ops, struct net_device *dev,

		int initial_ref, int initial_obsolete, int flags)

		int initial_ref, int initial_obsolete, unsigned short flags)

{

	struct dst_entry *dst;
@@ -188,6 +188,7 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev, 
	dst->__use = 0;

	dst->lastuse = jiffies;

	dst->flags = flags;

	dst->pending_confirm = 0;

	dst->next = NULL;

	if (!(flags & DST_NOCOUNT))

		dst_entries_add(ops, 1);

net/ipv4/ip_output.c

+1 −1
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ static inline int ip_finish_output2(struct sk_buff *skb) 
	if (unlikely(!neigh))

		neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);

	if (neigh) {

		int res = neigh_output(neigh, skb);

		int res = dst_neigh_output(dst, neigh, skb);



		rcu_read_unlock_bh();

		return res;

net/ipv4/tcp_input.c

+13 −6
Original line number Diff line number Diff line
@@ -740,13 +740,13 @@ void tcp_update_metrics(struct sock *sk) 
	if (sysctl_tcp_nometrics_save)

		return;



	dst_confirm(dst);



	if (dst && (dst->flags & DST_HOST)) {

		const struct inet_connection_sock *icsk = inet_csk(sk);

		int m;

		unsigned long rtt;



		dst_confirm(dst);



		if (icsk->icsk_backoff || !tp->srtt) {

			/* This session failed to estimate rtt. Why?

			 * Probably, no packets returned in time.
@@ -3869,9 +3869,11 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) 
			tcp_cong_avoid(sk, ack, prior_in_flight);

	}



	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP))

		dst_confirm(__sk_dst_get(sk));



	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) {

		struct dst_entry *dst = __sk_dst_get(sk);

		if (dst)

			dst_confirm(dst);

	}

	return 1;



no_queue:
@@ -6140,9 +6142,14 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 


		case TCP_FIN_WAIT1:

			if (tp->snd_una == tp->write_seq) {

				struct dst_entry *dst;



				tcp_set_state(sk, TCP_FIN_WAIT2);

				sk->sk_shutdown |= SEND_SHUTDOWN;

				dst_confirm(__sk_dst_get(sk));



				dst = __sk_dst_get(sk);

				if (dst)

					dst_confirm(dst);



				if (!sock_flag(sk, SOCK_DEAD))

					/* Wake up lingering close() */