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Commit 296f7ea7 authored by Satoru Moriya's avatar Satoru Moriya Committed by David S. Miller
Browse files

udp: add tracepoints for queueing skb to rcvbuf 



This patch adds a tracepoint to __udp_queue_rcv_skb to get the
return value of ip_queue_rcv_skb. It indicates why kernel drops
a packet at this point.

ip_queue_rcv_skb returns following values in the packet drop case:

rcvbuf is full                 : -ENOMEM
sk_filter returns error        : -EINVAL, -EACCESS, -ENOMEM, etc.
__sk_mem_schedule returns error: -ENOBUF

Signed-off-by: default avatarSatoru Moriya <satoru.moriya@hds.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dec17b74

include/trace/events/udp.h

0 → 100644
+32 −0
Original line number Diff line number Diff line 
#undef TRACE_SYSTEM

#define TRACE_SYSTEM udp



#if !defined(_TRACE_UDP_H) || defined(TRACE_HEADER_MULTI_READ)

#define _TRACE_UDP_H



#include <linux/udp.h>

#include <linux/tracepoint.h>



TRACE_EVENT(udp_fail_queue_rcv_skb,



	TP_PROTO(int rc, struct sock *sk),



	TP_ARGS(rc, sk),



	TP_STRUCT__entry(

		__field(int, rc)

		__field(__u16, lport)

	),



	TP_fast_assign(

		__entry->rc = rc;

		__entry->lport = inet_sk(sk)->inet_num;

	),



	TP_printk("rc=%d port=%hu", __entry->rc, __entry->lport)

);



#endif /* _TRACE_UDP_H */



/* This part must be outside protection */

#include <trace/define_trace.h>

net/core/net-traces.c

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <trace/events/skb.h>

#include <trace/events/net.h>

#include <trace/events/napi.h>

#include <trace/events/udp.h>



EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);

net/ipv4/udp.c

+2 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ 
#include <net/route.h>

#include <net/checksum.h>

#include <net/xfrm.h>

#include <trace/events/udp.h>

#include "udp_impl.h"



struct udp_table udp_table __read_mostly;
@@ -1363,6 +1364,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 
					 is_udplite);

		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);

		kfree_skb(skb);

		trace_udp_fail_queue_rcv_skb(rc, sk);

		return -1;

	}