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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: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Menglong Dong 2022-01-09 14:36:27 +08:00 committed by Jakub Kicinski
parent c504e5c2f9
commit 8512559741
3 changed files with 19 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/skbuff.h
View File

@ -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,
};

4
include/trace/events/skb.h
View File

@ -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

14
net/ipv4/tcp_ipv4.c
View File

@ -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: