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net: tcp: use tcp_drop_reason() for tcp_data_queue()

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Replace tcp_drop() used in tcp_data_queue() with tcp_drop_reason().
Following drop reasons are introduced:

SKB_DROP_REASON_TCP_ZEROWINDOW
SKB_DROP_REASON_TCP_OLD_DATA
SKB_DROP_REASON_TCP_OVERWINDOW

SKB_DROP_REASON_TCP_OLD_DATA is used for the case that end_seq of skb
less than the left edges of receive window. (Maybe there is a better
name?)

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 15:06:36 +08:00 committed by David S. Miller
parent 2a968ef60e
commit a7ec381049
3 changed files with 27 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
include/linux/skbuff.h
View file

@ -363,6 +363,19 @@ enum skb_drop_reason {
* LINUX_MIB_TCPBACKLOGDROP)
*/
SKB_DROP_REASON_TCP_FLAGS, /* TCP flags invalid */
SKB_DROP_REASON_TCP_ZEROWINDOW, /* TCP receive window size is zero,
* see LINUX_MIB_TCPZEROWINDOWDROP
*/
SKB_DROP_REASON_TCP_OLD_DATA, /* the TCP data reveived is already
* received before (spurious retrans
* may happened), see
* LINUX_MIB_DELAYEDACKLOST
*/
SKB_DROP_REASON_TCP_OVERWINDOW, /* the TCP data is out of window,
* the seq of the first byte exceed
* the right edges of receive
* window
*/
SKB_DROP_REASON_MAX,
};

3
include/trace/events/skb.h
View file

@ -33,6 +33,9 @@
EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE) \
EM(SKB_DROP_REASON_SOCKET_BACKLOG, SOCKET_BACKLOG) \
EM(SKB_DROP_REASON_TCP_FLAGS, TCP_FLAGS) \
EM(SKB_DROP_REASON_TCP_ZEROWINDOW, TCP_ZEROWINDOW) \
EM(SKB_DROP_REASON_TCP_OLD_DATA, TCP_OLD_DATA) \
EM(SKB_DROP_REASON_TCP_OVERWINDOW, TCP_OVERWINDOW) \
EMe(SKB_DROP_REASON_MAX, MAX)
#undef EM

13
net/ipv4/tcp_input.c
View file

@ -4988,6 +4988,7 @@ void tcp_data_ready(struct sock *sk)
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
enum skb_drop_reason reason;
bool fragstolen;
int eaten;
@ -5006,6 +5007,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
skb_dst_drop(skb);
__skb_pull(skb, tcp_hdr(skb)->doff * 4);
reason = SKB_DROP_REASON_NOT_SPECIFIED;
tp->rx_opt.dsack = 0;
/* Queue data for delivery to the user.
@ -5014,6 +5016,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
*/
if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {
if (tcp_receive_window(tp) == 0) {
reason = SKB_DROP_REASON_TCP_ZEROWINDOW;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
}
@ -5023,6 +5026,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
if (skb_queue_len(&sk->sk_receive_queue) == 0)
sk_forced_mem_schedule(sk, skb->truesize);
else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
reason = SKB_DROP_REASON_PROTO_MEM;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
sk->sk_data_ready(sk);
goto drop;
@ -5059,6 +5063,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
tcp_rcv_spurious_retrans(sk, skb);
/* A retransmit, 2nd most common case. Force an immediate ack. */
reason = SKB_DROP_REASON_TCP_OLD_DATA;
NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST);
tcp_dsack_set(sk, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
@ -5066,13 +5071,16 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_schedule_ack(sk);
drop:
tcp_drop(sk, skb);
tcp_drop_reason(sk, skb, reason);
return;
}
/* Out of window. F.e. zero window probe. */
if (!before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt + tcp_receive_window(tp)))
if (!before(TCP_SKB_CB(skb)->seq,
tp->rcv_nxt + tcp_receive_window(tp))) {
reason = SKB_DROP_REASON_TCP_OVERWINDOW;
goto out_of_window;
}
if (before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) {
/* Partial packet, seq < rcv_next < end_seq */
@ -5082,6 +5090,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
* remembering D-SACK for its head made in previous line.
*/
if (!tcp_receive_window(tp)) {
reason = SKB_DROP_REASON_TCP_ZEROWINDOW;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPZEROWINDOWDROP);
goto out_of_window;
}