* [PATCH] net: tcp_drop adds `reason` v5
@ 2021-09-13 13:00 Zhongya Yan
2021-09-13 16:26 ` Eric Dumazet
0 siblings, 1 reply; 2+ messages in thread
From: Zhongya Yan @ 2021-09-13 13:00 UTC (permalink / raw)
To: edumazet, rostedt, brendan.d.gregg
Cc: netdev, linux-kernel, kuba, mingo, davem, yoshfuji, dsahern, yhs,
2228598786, Zhongya Yan
Description information in the reason field of tcp_drop, "Tcp" is changed to "TCP"
Feel free to suggest changes
Signed-off-by: Zhongya Yan <yan2228598786@gmail.com>
---
include/trace/events/tcp.h | 62 ++++++++++++++++++
net/ipv4/tcp_input.c | 126 +++++++++++++++++++++++--------------
2 files changed, 142 insertions(+), 46 deletions(-)
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 521059d8dc0a..68bbe8741ce8 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -371,6 +371,68 @@ DEFINE_EVENT(tcp_event_skb, tcp_bad_csum,
TP_ARGS(skb)
);
+TRACE_EVENT(tcp_drop,
+ TP_PROTO(struct sock *sk, struct sk_buff *skb, int field, const char *reason),
+
+ TP_ARGS(sk, skb, field, reason),
+
+ TP_STRUCT__entry(
+ __array(__u8, saddr, sizeof(struct sockaddr_in6))
+ __array(__u8, daddr, sizeof(struct sockaddr_in6))
+ __field(__u16, sport)
+ __field(__u16, dport)
+ __field(__u32, mark)
+ __field(__u16, data_len)
+ __field(__u32, snd_nxt)
+ __field(__u32, snd_una)
+ __field(__u32, snd_cwnd)
+ __field(__u32, ssthresh)
+ __field(__u32, snd_wnd)
+ __field(__u32, srtt)
+ __field(__u32, rcv_wnd)
+ __field(__u64, sock_cookie)
+ __field(int, field)
+ __string(reason, reason)
+ ),
+
+ TP_fast_assign(
+ const struct tcphdr *th = (const struct tcphdr *)skb->data;
+ const struct inet_sock *inet = inet_sk(sk);
+ const struct tcp_sock *tp = tcp_sk(sk);
+
+ memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
+ memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
+
+ TP_STORE_ADDR_PORTS(__entry, inet, sk);
+
+ __entry->sport = ntohs(inet->inet_sport);
+ __entry->dport = ntohs(inet->inet_dport);
+ __entry->mark = skb->mark;
+
+ __entry->data_len = skb->len - __tcp_hdrlen(th);
+ __entry->snd_nxt = tp->snd_nxt;
+ __entry->snd_una = tp->snd_una;
+ __entry->snd_cwnd = tp->snd_cwnd;
+ __entry->snd_wnd = tp->snd_wnd;
+ __entry->rcv_wnd = tp->rcv_wnd;
+ __entry->ssthresh = tcp_current_ssthresh(sk);
+ __entry->srtt = tp->srtt_us >> 3;
+ __entry->sock_cookie = sock_gen_cookie(sk);
+ __entry->field = field;
+
+ __assign_str(reason, reason);
+ ),
+
+ TP_printk("src=%pISpc dest=%pISpc mark=%#x data_len=%d snd_nxt=%#x snd_una=%#x \
+ snd_cwnd=%u ssthresh=%u snd_wnd=%u srtt=%u rcv_wnd=%u \
+ sock_cookie=%llx field=%d reason=%s",
+ __entry->saddr, __entry->daddr, __entry->mark,
+ __entry->data_len, __entry->snd_nxt, __entry->snd_una,
+ __entry->snd_cwnd, __entry->ssthresh, __entry->snd_wnd,
+ __entry->srtt, __entry->rcv_wnd, __entry->sock_cookie,
+ __entry->field, __get_str(reason))
+);
+
#endif /* _TRACE_TCP_H */
/* This part must be outside protection */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3f7bd7ae7d7a..1cebdcafb00f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4675,8 +4675,10 @@ static bool tcp_ooo_try_coalesce(struct sock *sk,
return res;
}
-static void tcp_drop(struct sock *sk, struct sk_buff *skb)
+static void tcp_drop(struct sock *sk, struct sk_buff *skb,
+ int field, const char *reason)
{
+ trace_tcp_drop(sk, skb, field, reason);
sk_drops_add(sk, skb);
__kfree_skb(skb);
}
@@ -4708,7 +4710,7 @@ static void tcp_ofo_queue(struct sock *sk)
rb_erase(&skb->rbnode, &tp->out_of_order_queue);
if (unlikely(!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))) {
- tcp_drop(sk, skb);
+ tcp_drop(sk, skb, LINUX_MIB_TCPOFOQUEUE, "TCP queue error");
continue;
}
@@ -4764,7 +4766,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
sk->sk_data_ready(sk);
- tcp_drop(sk, skb);
+ tcp_drop(sk, skb, LINUX_MIB_TCPOFODROP, "TCP rmem failed");
return;
}
@@ -4827,7 +4829,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
/* All the bits are present. Drop. */
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPOFOMERGE);
- tcp_drop(sk, skb);
+ tcp_drop(sk, skb, LINUX_MIB_TCPOFOMERGE, "TCP bits are present");
skb = NULL;
tcp_dsack_set(sk, seq, end_seq);
goto add_sack;
@@ -4846,7 +4848,9 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
TCP_SKB_CB(skb1)->end_seq);
NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPOFOMERGE);
- tcp_drop(sk, skb1);
+ tcp_drop(sk, skb1, LINUX_MIB_TCPOFOMERGE,
+ "TCP replace(skb.seq eq skb1.seq)");
+
goto merge_right;
}
} else if (tcp_ooo_try_coalesce(sk, skb1,
@@ -4874,7 +4878,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
TCP_SKB_CB(skb1)->end_seq);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
- tcp_drop(sk, skb1);
+ tcp_drop(sk, skb1, LINUX_MIB_TCPOFOMERGE, "TCP useless other segments");
}
/* If there is no skb after us, we are the last_skb ! */
if (!skb1)
@@ -5010,7 +5014,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
sk->sk_data_ready(sk);
- goto drop;
+ tcp_drop(sk, skb, LINUX_MIB_TCPRCVQDROP, "TCP rmem failed");
+ goto end;
}
eaten = tcp_queue_rcv(sk, skb, &fragstolen);
@@ -5050,8 +5055,8 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
out_of_window:
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_schedule_ack(sk);
-drop:
- tcp_drop(sk, skb);
+ tcp_drop(sk, skb, LINUX_MIB_TCPZEROWINDOWDROP, "TCP out of order or zero window");
+end:
return;
}
@@ -5308,7 +5313,7 @@ static bool tcp_prune_ofo_queue(struct sock *sk)
prev = rb_prev(node);
rb_erase(node, &tp->out_of_order_queue);
goal -= rb_to_skb(node)->truesize;
- tcp_drop(sk, rb_to_skb(node));
+ tcp_drop(sk, rb_to_skb(node), LINUX_MIB_OFOPRUNED, "TCP drop out-of-order queue");
if (!prev || goal <= 0) {
sk_mem_reclaim(sk);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
@@ -5643,7 +5648,8 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
LINUX_MIB_TCPACKSKIPPEDPAWS,
&tp->last_oow_ack_time))
tcp_send_dupack(sk, skb);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_PAWSESTABREJECTED, "TCP PAWS seq first");
+ goto end;
}
/* Reset is accepted even if it did not pass PAWS. */
}
@@ -5666,7 +5672,8 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
} else if (tcp_reset_check(sk, skb)) {
tcp_reset(sk, skb);
}
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_PAWSESTABREJECTED, "TCP check sequence number");
+ goto end;
}
/* Step 2: check RST bit */
@@ -5711,7 +5718,8 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
tcp_fastopen_active_disable(sk);
tcp_send_challenge_ack(sk, skb);
}
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPCHALLENGEACK, "TCP check RST bit ");
+ goto end;
}
/* step 3: check security and precedence [ignored] */
@@ -5725,15 +5733,15 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE);
tcp_send_challenge_ack(sk, skb);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPSYNCHALLENGE, "TCP check for a SYN");
+ goto end;
}
bpf_skops_parse_hdr(sk, skb);
return true;
-discard:
- tcp_drop(sk, skb);
+end:
return false;
}
@@ -5851,7 +5859,8 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
return;
} else { /* Header too small */
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
- goto discard;
+ tcp_drop(sk, skb, TCP_MIB_INERRS, "TCP header too small");
+ goto end;
}
} else {
int eaten = 0;
@@ -5905,8 +5914,10 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
if (len < (th->doff << 2) || tcp_checksum_complete(skb))
goto csum_error;
- if (!th->ack && !th->rst && !th->syn)
- goto discard;
+ if (!th->ack && !th->rst && !th->syn) {
+ tcp_drop(sk, skb, LINUX_MIB_TCPSLOWSTARTRETRANS, "TCP state not in ack|rst|syn");
+ goto end;
+ }
/*
* Standard slow path.
@@ -5916,8 +5927,10 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
return;
step5:
- if (tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0)
- goto discard;
+ if (tcp_ack(sk, skb, FLAG_SLOWPATH | FLAG_UPDATE_TS_RECENT) < 0) {
+ tcp_drop(sk, skb, LINUX_MIB_TCPSACKDISCARD, "TCP ack have not sent yet");
+ goto end;
+ }
tcp_rcv_rtt_measure_ts(sk, skb);
@@ -5935,9 +5948,10 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb)
trace_tcp_bad_csum(skb);
TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
+ tcp_drop(sk, skb, TCP_MIB_CSUMERRORS, "TCP csum error");
-discard:
- tcp_drop(sk, skb);
+end:
+ return;
}
EXPORT_SYMBOL(tcp_rcv_established);
@@ -6137,7 +6151,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
if (th->rst) {
tcp_reset(sk, skb);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_NUM, "TCP reset");
+ goto end;
}
/* rfc793:
@@ -6226,9 +6241,9 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS);
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
TCP_DELACK_MAX, TCP_RTO_MAX);
+ tcp_drop(sk, skb, LINUX_MIB_TCPFASTOPENACTIVE, "TCP fast open ack error");
-discard:
- tcp_drop(sk, skb);
+end:
return 0;
} else {
tcp_send_ack(sk);
@@ -6301,7 +6316,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
*/
return -1;
#else
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_SYNCOOKIESRECV, "TCP syn received error");
+ goto end;
#endif
}
/* "fifth, if neither of the SYN or RST bits is set then
@@ -6311,7 +6327,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
discard_and_undo:
tcp_clear_options(&tp->rx_opt);
tp->rx_opt.mss_clamp = saved_clamp;
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPSACKDISCARD, "TCP not neither of SYN or RST");
+ goto end;
reset_and_undo:
tcp_clear_options(&tp->rx_opt);
@@ -6369,18 +6386,23 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
switch (sk->sk_state) {
case TCP_CLOSE:
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPABORTONCLOSE, "TCP close");
+ goto end;
case TCP_LISTEN:
if (th->ack)
return 1;
- if (th->rst)
- goto discard;
+ if (th->rst) {
+ tcp_drop(sk, skb, LINUX_MIB_LISTENDROPS, "TCP rst");
+ goto end;
+ }
if (th->syn) {
- if (th->fin)
- goto discard;
+ if (th->fin) {
+ tcp_drop(sk, skb, LINUX_MIB_LISTENDROPS, "TCP fin");
+ goto end;
+ }
/* It is possible that we process SYN packets from backlog,
* so we need to make sure to disable BH and RCU right there.
*/
@@ -6395,7 +6417,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
consume_skb(skb);
return 0;
}
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_LISTENDROPS, "TCP syn");
+ goto end;
case TCP_SYN_SENT:
tp->rx_opt.saw_tstamp = 0;
@@ -6421,12 +6444,16 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
sk->sk_state != TCP_FIN_WAIT1);
- if (!tcp_check_req(sk, skb, req, true, &req_stolen))
- goto discard;
+ if (!tcp_check_req(sk, skb, req, true, &req_stolen)) {
+ tcp_drop(sk, skb, LINUX_MIB_LISTENDROPS, "TCP check req error");
+ goto end;
+ }
}
- if (!th->ack && !th->rst && !th->syn)
- goto discard;
+ if (!th->ack && !th->rst && !th->syn) {
+ tcp_drop(sk, skb, LINUX_MIB_LISTENDROPS, "TCP not ack|rst|syn");
+ goto end;
+ }
if (!tcp_validate_incoming(sk, skb, th, 0))
return 0;
@@ -6440,7 +6467,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
if (sk->sk_state == TCP_SYN_RECV)
return 1; /* send one RST */
tcp_send_challenge_ack(sk, skb);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPCHALLENGEACK, "TCP check ack failed");
+ goto end;
}
switch (sk->sk_state) {
case TCP_SYN_RECV:
@@ -6533,7 +6561,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
inet_csk_reset_keepalive_timer(sk, tmo);
} else {
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPABORTONDATA, "TCP fin wait2");
+ goto end;
}
break;
}
@@ -6541,7 +6570,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
case TCP_CLOSING:
if (tp->snd_una == tp->write_seq) {
tcp_time_wait(sk, TCP_TIME_WAIT, 0);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TIMEWAITED, "TCP time wait");
+ goto end;
}
break;
@@ -6549,7 +6579,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
if (tp->snd_una == tp->write_seq) {
tcp_update_metrics(sk);
tcp_done(sk);
- goto discard;
+ tcp_drop(sk, skb, LINUX_MIB_TCPPUREACKS, "TCP last ack");
+ goto end;
}
break;
}
@@ -6566,8 +6597,10 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
/* If a subflow has been reset, the packet should not
* continue to be processed, drop the packet.
*/
- if (sk_is_mptcp(sk) && !mptcp_incoming_options(sk, skb))
- goto discard;
+ if (sk_is_mptcp(sk) && !mptcp_incoming_options(sk, skb)) {
+ tcp_drop(sk, skb, LINUX_MIB_TCPPUREACKS, "TCP subflow been reset");
+ goto end;
+ }
break;
}
fallthrough;
@@ -6599,9 +6632,10 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
}
if (!queued) {
-discard:
- tcp_drop(sk, skb);
+ tcp_drop(sk, skb, LINUX_MIB_TCPOFOQUEUE, "TCP rcv synsent state process");
}
+
+end:
return 0;
}
EXPORT_SYMBOL(tcp_rcv_state_process);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: tcp_drop adds `reason` v5
2021-09-13 13:00 [PATCH] net: tcp_drop adds `reason` v5 Zhongya Yan
@ 2021-09-13 16:26 ` Eric Dumazet
0 siblings, 0 replies; 2+ messages in thread
From: Eric Dumazet @ 2021-09-13 16:26 UTC (permalink / raw)
To: Zhongya Yan
Cc: Steven Rostedt, Brendan Gregg, netdev, LKML, Jakub Kicinski,
Ingo Molnar, David Miller, Hideaki YOSHIFUJI, David Ahern,
Yonghong Song, 2228598786
On Mon, Sep 13, 2021 at 6:01 AM Zhongya Yan <yan2228598786@gmail.com> wrote:
>
> Description information in the reason field of tcp_drop, "Tcp" is changed to "TCP"
> Feel free to suggest changes
>
This is a cryptic changelog.
Have you forgotten to copy/paste important information ?
We would like something that explains what the patch is about, and
eventually how to use the new functionality.
Do not assume future readers of linux TCP stack will have instant
access to all your prior versions
Also patch is about tcp, net: prefix in patch title should be tcp:
Thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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