From: Menglong Dong <imagedong@xxxxxxxxxxx>
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?)
Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
---
include/linux/skbuff.h | 13 +++++++++++++
include/trace/events/skb.h | 3 +++
net/ipv4/tcp_input.c | 13 +++++++++++--
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index dcf9d8bd0079..62a0d7d78f6f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -358,6 +358,19 @@ 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,
};
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index d332e7313a61..cc1c8f7eaf72 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -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
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 8cb0ea34aa49..c042711fb5a2 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4991,6 +4991,7 @@ 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;
@@ -5009,6 +5010,7 @@ 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.
@@ -5017,6 +5019,7 @@ 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;
}
@@ -5026,6 +5029,7 @@ 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;
@@ -5062,6 +5066,7 @@ 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);
@@ -5069,13 +5074,16 @@ 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 */
@@ -5085,6 +5093,7 @@ 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;
}
--
2.34.1
