Commit de68b039 authored by Tom Parkin's avatar Tom Parkin Committed by David S. Miller
Browse files

l2tp: capture more tx errors in data plane stats 



l2tp_xmit_skb has a number of failure paths which are not reflected in
the tunnel and session statistics because the stats are updated by
l2tp_xmit_core.  Hence any errors occurring before l2tp_xmit_core is
called are missed from the statistics.

Refactor the transmit path slightly to capture all error paths.

l2tp_xmit_skb now leaves all the actual work of transmission to
l2tp_xmit_core, and updates the statistics based on l2tp_xmit_core's
return code.

Signed-off-by: default avatarTom Parkin <tparkin@katalix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c9ccd4c6

net/l2tp/l2tp_core.c

+37 −34
Original line number Diff line number Diff line
@@ -985,56 +985,39 @@ static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) 
	return bufp - optr;

}



static void l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, struct flowi *fl)

/* Queue the packet to IP for output: tunnel socket lock must be held */

static int l2tp_xmit_queue(struct l2tp_tunnel *tunnel, struct sk_buff *skb, struct flowi *fl)

{

	struct l2tp_tunnel *tunnel = session->tunnel;

	unsigned int len = skb->len;

	int error;

	int err;



	/* Queue the packet to IP for output */

	skb->ignore_df = 1;

	skb_dst_drop(skb);

#if IS_ENABLED(CONFIG_IPV6)

	if (l2tp_sk_is_v6(tunnel->sock))

		error = inet6_csk_xmit(tunnel->sock, skb, NULL);

		err = inet6_csk_xmit(tunnel->sock, skb, NULL);

	else

#endif

		error = ip_queue_xmit(tunnel->sock, skb, fl);

		err = ip_queue_xmit(tunnel->sock, skb, fl);



	/* Update stats */

	if (error >= 0) {

		atomic_long_inc(&tunnel->stats.tx_packets);

		atomic_long_add(len, &tunnel->stats.tx_bytes);

		atomic_long_inc(&session->stats.tx_packets);

		atomic_long_add(len, &session->stats.tx_bytes);

	} else {

		atomic_long_inc(&tunnel->stats.tx_errors);

		atomic_long_inc(&session->stats.tx_errors);

	}

	return err >= 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;

}



/* If caller requires the skb to have a ppp header, the header must be

 * inserted in the skb data before calling this function.

 */

int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb)

static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb)

{

	int data_len = skb->len;

	struct l2tp_tunnel *tunnel = session->tunnel;

	unsigned int data_len = skb->len;

	struct sock *sk = tunnel->sock;

	struct flowi *fl;

	struct udphdr *uh;

	struct inet_sock *inet;

	int headroom;

	int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;

	int udp_len;

	int headroom, uhlen, udp_len;

	int ret = NET_XMIT_SUCCESS;

	struct inet_sock *inet;

	struct udphdr *uh;



	/* Check that there's enough headroom in the skb to insert IP,

	 * UDP and L2TP headers. If not enough, expand it to

	 * make room. Adjust truesize.

	 */

	headroom = NET_SKB_PAD + sizeof(struct iphdr) +

		uhlen + session->hdr_len;

	uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(*uh) : 0;

	headroom = NET_SKB_PAD + sizeof(struct iphdr) + uhlen + session->hdr_len;

	if (skb_cow_head(skb, headroom)) {

		kfree_skb(skb);

		return NET_XMIT_DROP;
@@ -1048,8 +1031,7 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) 


	/* Reset skb netfilter state */

	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));

	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |

			      IPSKB_REROUTED);

	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED);

	nf_reset_ct(skb);



	bh_lock_sock(sk);
@@ -1069,7 +1051,6 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) 
	}



	inet = inet_sk(sk);

	fl = &inet->cork.fl;

	switch (tunnel->encap) {

	case L2TP_ENCAPTYPE_UDP:

		/* Setup UDP header */
@@ -1097,12 +1078,34 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb) 
		break;

	}



	l2tp_xmit_core(session, skb, fl);

	ret = l2tp_xmit_queue(tunnel, skb, &inet->cork.fl);



out_unlock:

	bh_unlock_sock(sk);



	return ret;

}



/* If caller requires the skb to have a ppp header, the header must be

 * inserted in the skb data before calling this function.

 */

int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb)

{

	unsigned int len = skb->len;

	int ret;



	ret = l2tp_xmit_core(session, skb);

	if (ret == NET_XMIT_SUCCESS) {

		atomic_long_inc(&session->tunnel->stats.tx_packets);

		atomic_long_add(len, &session->tunnel->stats.tx_bytes);

		atomic_long_inc(&session->stats.tx_packets);

		atomic_long_add(len, &session->stats.tx_bytes);

	} else {

		atomic_long_inc(&session->tunnel->stats.tx_errors);

		atomic_long_inc(&session->stats.tx_errors);

	}

	return ret;

}

EXPORT_SYMBOL_GPL(l2tp_xmit_skb);



/*****************************************************************************

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