Re: [PATCH net-next v2 4/6] tcp: rstreason: introduce SK_RST_REASON_TCP_STATE for active reset
From: Eric Dumazet <edumazet@google.com>
Date: 2024-08-01 06:56:25
On Wed, Jul 31, 2024 at 2:10 PM Jason Xing [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Jason Xing <kernelxing@tencent.com> Introducing a new type TCP_STATE to handle some reset conditions appearing in RFC 793 due to its socket state. Actually, we can look into RFC 9293 which has no discrepancy about this part. Signed-off-by: Jason Xing <kernelxing@tencent.com> --- V2 Link: https://lore.kernel.org/all/20240730200633.93761-1-kuniyu@amazon.com/ (local) 1. use RFC 9293 instead of RFC 793 which is too old (Kuniyuki) --- include/net/rstreason.h | 6 ++++++ net/ipv4/tcp.c | 4 ++-- net/ipv4/tcp_timer.c | 2 +- 3 files changed, 9 insertions(+), 3 deletions(-)diff --git a/include/net/rstreason.h b/include/net/rstreason.h index eef658da8952..bbf20d0bbde7 100644 --- a/include/net/rstreason.h +++ b/include/net/rstreason.h@@ -20,6 +20,7 @@ FN(TCP_ABORT_ON_CLOSE) \ FN(TCP_ABORT_ON_LINGER) \ FN(TCP_ABORT_ON_MEMORY) \ + FN(TCP_STATE) \ FN(MPTCP_RST_EUNSPEC) \ FN(MPTCP_RST_EMPTCP) \ FN(MPTCP_RST_ERESOURCE) \@@ -102,6 +103,11 @@ enum sk_rst_reason { * corresponding to LINUX_MIB_TCPABORTONMEMORY */ SK_RST_REASON_TCP_ABORT_ON_MEMORY, + /** + * @SK_RST_REASON_TCP_STATE: abort on tcp state + * Please see RFC 9293 for all possible reset conditions + */ + SK_RST_REASON_TCP_STATE, /* Copy from include/uapi/linux/mptcp.h. * These reset fields will not be changed since they adhere todiff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fd928c447ce8..64a49cb714e1 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c@@ -3031,7 +3031,7 @@ int tcp_disconnect(struct sock *sk, int flags) /* The last check adjusts for discrepancy of Linux wrt. RFC * states */ - tcp_send_active_reset(sk, gfp_any(), SK_RST_REASON_NOT_SPECIFIED); + tcp_send_active_reset(sk, gfp_any(), SK_RST_REASON_TCP_STATE);
I disagree with this. tcp_disconnect() is initiated by the user. You are conflating two possible conditions : 1) tcp_need_reset(old_state) 2) (tp->snd_nxt != tp->write_seq && (1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK)))
quoted hunk ↗ jump to hunk
WRITE_ONCE(sk->sk_err, ECONNRESET); } else if (old_state == TCP_SYN_SENT) WRITE_ONCE(sk->sk_err, ECONNRESET);@@ -4649,7 +4649,7 @@ int tcp_abort(struct sock *sk, int err) if (!sock_flag(sk, SOCK_DEAD)) { if (tcp_need_reset(sk->sk_state)) tcp_send_active_reset(sk, GFP_ATOMIC, - SK_RST_REASON_NOT_SPECIFIED); + SK_RST_REASON_TCP_STATE); tcp_done_with_error(sk, err); }diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 0fba4a4fb988..3910f6d8614e 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c@@ -779,7 +779,7 @@ static void tcp_keepalive_timer (struct timer_list *t) goto out; } } - tcp_send_active_reset(sk, GFP_ATOMIC, SK_RST_REASON_NOT_SPECIFIED); + tcp_send_active_reset(sk, GFP_ATOMIC, SK_RST_REASON_TCP_STATE); goto death; } --2.37.3