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net: tcp: add skb drop reasons to tcp_add_backlog()

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Pass the address of drop_reason to tcp_add_backlog() to store the
reasons for skb drops when fails. Following drop reasons are
introduced:

SKB_DROP_REASON_SOCKET_BACKLOG

Reviewed-by: Mengen Sun <mengensun@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Menglong Dong
2022-02-20 15:06:33 +08:00
committed by David S. Miller
parent 643b622b51
commit 7a26dc9e7b
5 changed files with 13 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/skbuff.h
View File

@ -358,6 +358,10 @@ enum skb_drop_reason {
* corresponding to * corresponding to
* LINUX_MIB_TCPMD5FAILURE * LINUX_MIB_TCPMD5FAILURE
*/ */
SKB_DROP_REASON_SOCKET_BACKLOG, /* failed to add skb to socket
* backlog (see
* LINUX_MIB_TCPBACKLOGDROP)
*/
SKB_DROP_REASON_MAX, SKB_DROP_REASON_MAX,
}; };

3
include/net/tcp.h
View File

@ -1367,7 +1367,8 @@ static inline bool tcp_checksum_complete(struct sk_buff *skb)
__skb_checksum_complete(skb); __skb_checksum_complete(skb);
} }
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb); bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason *reason);
#ifdef CONFIG_INET #ifdef CONFIG_INET
void __sk_defer_free_flush(struct sock *sk); void __sk_defer_free_flush(struct sock *sk);

1
include/trace/events/skb.h
View File

@ -31,6 +31,7 @@
EM(SKB_DROP_REASON_TCP_MD5UNEXPECTED, \ EM(SKB_DROP_REASON_TCP_MD5UNEXPECTED, \
TCP_MD5UNEXPECTED) \ TCP_MD5UNEXPECTED) \
EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE) \ EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE) \
EM(SKB_DROP_REASON_SOCKET_BACKLOG, SOCKET_BACKLOG) \
EMe(SKB_DROP_REASON_MAX, MAX) EMe(SKB_DROP_REASON_MAX, MAX)
#undef EM #undef EM

7
net/ipv4/tcp_ipv4.c
View File

@ -1811,7 +1811,8 @@ int tcp_v4_early_demux(struct sk_buff *skb)
return 0; return 0;
} }
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb,
enum skb_drop_reason *reason)
{ {
u32 limit, tail_gso_size, tail_gso_segs; u32 limit, tail_gso_size, tail_gso_segs;
struct skb_shared_info *shinfo; struct skb_shared_info *shinfo;
@ -1837,6 +1838,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
if (unlikely(tcp_checksum_complete(skb))) { if (unlikely(tcp_checksum_complete(skb))) {
bh_unlock_sock(sk); bh_unlock_sock(sk);
trace_tcp_bad_csum(skb); trace_tcp_bad_csum(skb);
*reason = SKB_DROP_REASON_TCP_CSUM;
__TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
__TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
return true; return true;
@ -1925,6 +1927,7 @@ no_coalesce:
if (unlikely(sk_add_backlog(sk, skb, limit))) { if (unlikely(sk_add_backlog(sk, skb, limit))) {
bh_unlock_sock(sk); bh_unlock_sock(sk);
*reason = SKB_DROP_REASON_SOCKET_BACKLOG;
__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP); __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPBACKLOGDROP);
return true; return true;
} }
@ -2133,7 +2136,7 @@ process:
if (!sock_owned_by_user(sk)) { if (!sock_owned_by_user(sk)) {
ret = tcp_v4_do_rcv(sk, skb); ret = tcp_v4_do_rcv(sk, skb);
} else { } else {
if (tcp_add_backlog(sk, skb)) if (tcp_add_backlog(sk, skb, &drop_reason))
goto discard_and_relse; goto discard_and_relse;
} }
bh_unlock_sock(sk); bh_unlock_sock(sk);

2
net/ipv6/tcp_ipv6.c
View File

@ -1784,7 +1784,7 @@ process:
if (!sock_owned_by_user(sk)) { if (!sock_owned_by_user(sk)) {
ret = tcp_v6_do_rcv(sk, skb); ret = tcp_v6_do_rcv(sk, skb);
} else { } else {
if (tcp_add_backlog(sk, skb)) if (tcp_add_backlog(sk, skb, &drop_reason))
goto discard_and_relse; goto discard_and_relse;
} }
bh_unlock_sock(sk); bh_unlock_sock(sk);