diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-04-10 18:29:27 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-04-10 18:29:28 -0700 |
| commit | c1e0100c6aa5ee5cf773cb00355309e79b2fac1b (patch) | |
| tree | 17c840dfae170b04d08de7c499e63d17b69d98f5 /include | |
| parent | 709894c52c1cafa36fe2047ba5a0b83bdf398133 (diff) | |
| parent | c449d5f3a3d70b6223af8df2cadca3ca6eacb613 (diff) | |
Merge branch 'tcp-add-a-new-tw_paws-drop-reason'
Jiayuan Chen says:
====================
tcp: add a new TW_PAWS drop reason
Devices in the networking path, such as firewalls, NATs, or routers, which
can perform SNAT or DNAT, use addresses from their own limited address
pools to masquerade the source address during forwarding, causing PAWS
verification to fail more easily under TW status.
Currently, packet loss statistics for PAWS can only be viewed through MIB,
which is a global metric and cannot be precisely obtained through tracing
to get the specific 4-tuple of the dropped packet. In the past, we had to
use kprobe ret to retrieve relevant skb information from
tcp_timewait_state_process().
We add a drop_reason pointer and a new counter.
I didn't provide a packetdrill script.
I struggled for a long time to get packetdrill to fix the client port, but
ultimately failed to do so...
Instead, I wrote my own program to trigger PAWS, which can be found at
https://github.com/mrpre/nettrigger/tree/main
'''
//assume nginx running on 172.31.75.114:9999, current host is 172.31.75.115
iptables -t filter -I OUTPUT -p tcp --sport 12345 --tcp-flags RST RST -j DROP
./nettrigger -i eth0 -s 172.31.75.115:12345 -d 172.31.75.114:9999 -action paws
'''
v2: https://lore.kernel.org/5cdc1bdd9caee92a6ae932638a862fd5c67630e8@linux.dev
v3: https://lore.kernel.org/20250407140001.13886-1-jiayuan.chen@linux.dev
====================
Link: https://patch.msgid.link/20250409112614.16153-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/dropreason-core.h | 7 | ||||
| -rw-r--r-- | include/net/tcp.h | 3 | ||||
| -rw-r--r-- | include/uapi/linux/snmp.h | 1 |
3 files changed, 10 insertions, 1 deletions
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index e4fdc6b54cef..bea77934a235 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -40,6 +40,7 @@ FN(TCP_OFOMERGE) \ FN(TCP_RFC7323_PAWS) \ FN(TCP_RFC7323_PAWS_ACK) \ + FN(TCP_RFC7323_TW_PAWS) \ FN(TCP_RFC7323_TSECR) \ FN(TCP_LISTEN_OVERFLOW) \ FN(TCP_OLD_SEQUENCE) \ @@ -284,6 +285,12 @@ enum skb_drop_reason { */ SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK, /** + * @SKB_DROP_REASON_TCP_RFC7323_TW_PAWS: PAWS check, socket is in + * TIME_WAIT state. + * Corresponds to LINUX_MIB_PAWS_TW_REJECTED. + */ + SKB_DROP_REASON_TCP_RFC7323_TW_PAWS, + /** * @SKB_DROP_REASON_TCP_RFC7323_TSECR: PAWS check, invalid TSEcr. * Corresponds to LINUX_MIB_TSECRREJECTED. */ diff --git a/include/net/tcp.h b/include/net/tcp.h index 4450c384ef17..5078ad868fee 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -427,7 +427,8 @@ enum tcp_tw_status { enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, const struct tcphdr *th, - u32 *tw_isn); + u32 *tw_isn, + enum skb_drop_reason *drop_reason); struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, struct request_sock *req, bool fastopen, bool *lost_race, enum skb_drop_reason *drop_reason); diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index ec47f9b68a1b..1d234d7e1892 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -188,6 +188,7 @@ enum LINUX_MIB_PAWSESTABREJECTED, /* PAWSEstabRejected */ LINUX_MIB_TSECRREJECTED, /* TSEcrRejected */ LINUX_MIB_PAWS_OLD_ACK, /* PAWSOldAck */ + LINUX_MIB_PAWS_TW_REJECTED, /* PAWSTimewait */ LINUX_MIB_DELAYEDACKS, /* DelayedACKs */ LINUX_MIB_DELAYEDACKLOCKED, /* DelayedACKLocked */ LINUX_MIB_DELAYEDACKLOST, /* DelayedACKLost */ |