| Message ID | 20250324131805.23103-1-jiayuan.chen@linux.dev (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v1] tcp: Support skb PAWS drop reason when TIME-WAIT | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next, async |
| netdev/apply | fail | Patch does not apply to net-next-1 |
On Mon, 24 Mar 2025 21:18:05 +0800 Jiayuan Chen wrote: > When the server actively closes a connection and enters the TIME_WAIT > state, if PAWS validation fails, the discarded skb previously lacked a > corresponding reason identifier. This commit assigns the existing > SKB_DROP_REASON_TCP_RFC7323_PAWS as the reason for such drops. > > We use 'pwru' to capture drop reason. This patch does not apply cleanly to net-next: Applying: tcp: Support skb PAWS drop reason when TIME-WAIT Using index info to reconstruct a base tree... M include/net/tcp.h M net/ipv4/tcp_ipv4.c M net/ipv4/tcp_minisocks.c M net/ipv6/tcp_ipv6.c Falling back to patching base and 3-way merge... Auto-merging net/ipv6/tcp_ipv6.c CONFLICT (content): Merge conflict in net/ipv6/tcp_ipv6.c Auto-merging net/ipv4/tcp_minisocks.c Auto-merging net/ipv4/tcp_ipv4.c CONFLICT (content): Merge conflict in net/ipv4/tcp_ipv4.c Auto-merging include/net/tcp.h Recorded preimage for 'net/ipv4/tcp_ipv4.c' Recorded preimage for 'net/ipv6/tcp_ipv6.c' error: Failed to merge in the changes. hint: Use 'git am --show-current-patch=diff' to see the failed patch hint: When you have resolved this problem, run "git am --continue". hint: If you prefer to skip this patch, run "git am --skip" instead. hint: To restore the original branch and stop patching, run "git am --abort". hint: Disable this message with "git config set advice.mergeConflict false" Patch failed at 0001 tcp: Support skb PAWS drop reason when TIME-WAIT
diff --git a/include/net/tcp.h b/include/net/tcp.h index 2d08473a6dc0..16e6efef939a 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -388,7 +388,7 @@ 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); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 2632844d2c35..ad168a3a73bb 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2406,7 +2406,7 @@ int tcp_v4_rcv(struct sk_buff *skb) inet_twsk_put(inet_twsk(sk)); goto csum_error; } - switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn)) { + switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn, &drop_reason)) { case TCP_TW_SYN: { struct sock *sk2 = inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index b089b08e9617..39e5b55041f1 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -97,7 +97,7 @@ static void twsk_rcv_nxt_update(struct tcp_timewait_sock *tcptw, u32 seq, */ enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, - const struct tcphdr *th, u32 *tw_isn) + const struct tcphdr *th, u32 *tw_isn, enum skb_drop_reason *drop_reason) { struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw); u32 rcv_nxt = READ_ONCE(tcptw->tw_rcv_nxt); @@ -245,8 +245,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, return TCP_TW_SYN; } - if (paws_reject) + if (paws_reject) { + *drop_reason = SKB_DROP_REASON_TCP_RFC7323_PAWS; __NET_INC_STATS(twsk_net(tw), LINUX_MIB_PAWSESTABREJECTED); + } if (!th->rst) { /* In this case we must reset the TIMEWAIT timer. diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2debdf085a3b..66d30df95f7a 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1965,7 +1965,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) goto csum_error; } - switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn)) { + switch (tcp_timewait_state_process(inet_twsk(sk), skb, th, &isn, &drop_reason)) { case TCP_TW_SYN: { struct sock *sk2;
When the server actively closes a connection and enters the TIME_WAIT state, if PAWS validation fails, the discarded skb previously lacked a corresponding reason identifier. This commit assigns the existing SKB_DROP_REASON_TCP_RFC7323_PAWS as the reason for such drops. We use 'pwru' to capture drop reason. Before this commit: '''' ./pwru 'port 9999' 2025/03/24 13:46:03 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_NOT_SPECIFIED) ''' After this commit: ''' ./pwru 'port 9999' 2025/03/24 16:06:59 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_TCP_RFC7323_PAWS) ''' Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> --- My apologize. I struggled for a long time to get packetdrill to fix the client port, but ultimately failed to do so, which is why I couldn't provide a packetdrill script. Instead, I wrote my own program to trigger PAWS, which can be found at https://github.com/mrpre/nettrigger/tree/main --- include/net/tcp.h | 2 +- net/ipv4/tcp_ipv4.c | 2 +- net/ipv4/tcp_minisocks.c | 6 ++++-- net/ipv6/tcp_ipv6.c | 2 +- 4 files changed, 7 insertions(+), 5 deletions(-)