Commit 85125597 authored by Menglong Dong's avatar Menglong Dong Committed by Jakub Kicinski
Browse files

net: skb: use kfree_skb_reason() in tcp_v4_rcv() 



Replace kfree_skb() with kfree_skb_reason() in tcp_v4_rcv(). Following
drop reasons are added:

SKB_DROP_REASON_NO_SOCKET
SKB_DROP_REASON_PKT_TOO_SMALL
SKB_DROP_REASON_TCP_CSUM
SKB_DROP_REASON_TCP_FILTER

After this patch, 'kfree_skb' event will print message like this:

$           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
$              | |         |   |||||     |         |
          <idle>-0       [000] ..s1.    36.113438: kfree_skb: skbaddr=(____ptrval____) protocol=2048 location=(____ptrval____) reason: NO_SOCKET

The reason of skb drop is printed too.

Signed-off-by: default avatarMenglong Dong <imagedong@tencent.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c504e5c2

include/linux/skbuff.h

+4 −0
Original line number Diff line number Diff line
@@ -313,6 +313,10 @@ struct sk_buff; 
 */

enum skb_drop_reason {

	SKB_DROP_REASON_NOT_SPECIFIED,

	SKB_DROP_REASON_NO_SOCKET,

	SKB_DROP_REASON_PKT_TOO_SMALL,

	SKB_DROP_REASON_TCP_CSUM,

	SKB_DROP_REASON_TCP_FILTER,

	SKB_DROP_REASON_MAX,

};

include/trace/events/skb.h

+4 −0
Original line number Diff line number Diff line
@@ -11,6 +11,10 @@ 


#define TRACE_SKB_DROP_REASON					\

	EM(SKB_DROP_REASON_NOT_SPECIFIED, NOT_SPECIFIED)	\

	EM(SKB_DROP_REASON_NO_SOCKET, NO_SOCKET)		\

	EM(SKB_DROP_REASON_PKT_TOO_SMALL, PKT_TOO_SMALL)	\

	EM(SKB_DROP_REASON_TCP_CSUM, TCP_CSUM)			\

	EM(SKB_DROP_REASON_TCP_FILTER, TCP_FILTER)		\

	EMe(SKB_DROP_REASON_MAX, MAX)



#undef EM

net/ipv4/tcp_ipv4.c

+11 −3
Original line number Diff line number Diff line
@@ -1971,8 +1971,10 @@ int tcp_v4_rcv(struct sk_buff *skb) 
	const struct tcphdr *th;

	bool refcounted;

	struct sock *sk;

	int drop_reason;

	int ret;



	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;

	if (skb->pkt_type != PACKET_HOST)

		goto discard_it;
@@ -1984,8 +1986,10 @@ int tcp_v4_rcv(struct sk_buff *skb) 


	th = (const struct tcphdr *)skb->data;



	if (unlikely(th->doff < sizeof(struct tcphdr) / 4))

	if (unlikely(th->doff < sizeof(struct tcphdr) / 4)) {

		drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;

		goto bad_packet;

	}

	if (!pskb_may_pull(skb, th->doff * 4))

		goto discard_it;
@@ -2090,8 +2094,10 @@ int tcp_v4_rcv(struct sk_buff *skb) 


	nf_reset_ct(skb);



	if (tcp_filter(sk, skb))

	if (tcp_filter(sk, skb)) {

		drop_reason = SKB_DROP_REASON_TCP_FILTER;

		goto discard_and_relse;

	}

	th = (const struct tcphdr *)skb->data;

	iph = ip_hdr(skb);

	tcp_v4_fill_cb(skb, iph, th);
@@ -2124,6 +2130,7 @@ int tcp_v4_rcv(struct sk_buff *skb) 
	return ret;



no_tcp_socket:

	drop_reason = SKB_DROP_REASON_NO_SOCKET;

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))

		goto discard_it;
@@ -2131,6 +2138,7 @@ int tcp_v4_rcv(struct sk_buff *skb) 


	if (tcp_checksum_complete(skb)) {

csum_error:

		drop_reason = SKB_DROP_REASON_TCP_CSUM;

		trace_tcp_bad_csum(skb);

		__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);

bad_packet:
@@ -2141,7 +2149,7 @@ int tcp_v4_rcv(struct sk_buff *skb) 


discard_it:

	/* Discard frame. */

	kfree_skb(skb);

	kfree_skb_reason(skb, drop_reason);

	return 0;



discard_and_relse: