diff mbox series

[net-next,37/44] tcp: accecn: unset ECT if receive or send ACE=0 in AccECN negotiaion

Message ID 20241015102940.26157-38-chia-yu.chang@nokia-bell-labs.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series DualPI2, Accurate ECN, TCP Prague patch series | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 4 maintainers not CCed: edumazet@google.com pabeni@redhat.com dsahern@kernel.org kuba@kernel.org
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 6 this patch: 6
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns WARNING: line length of 89 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 2 this patch: 2
netdev/source_inline success Was 0 now: 0

Commit Message

Chia-Yu Chang (Nokia) Oct. 15, 2024, 10:29 a.m. UTC 
From: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>

Based on specification:
  https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt

3.1.5. Implications of AccECN Mode - A TCP Server in AccECN mode
MUST NOT set ECT on any packet for the rest of the connection, if
it has received or sent at least one valid SYN or Acceptable SYN/ACK
with (AE,CWR,ECE) = (0,0,0) during the handshake.

3.1.5 Implications of AccECN Mode - A host in AccECN mode that is
feeding back the IP-ECN field on a SYN or SYN/ACK: MUST feed back
the IP-ECN field on the latest valid SYN or acceptable
SYN/ACK to arrive.

Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
---
 net/ipv4/tcp_input.c     |  1 +
 net/ipv4/tcp_minisocks.c | 27 +++++++++++++++++----------
 net/ipv4/tcp_output.c    |  7 ++++---
 3 files changed, 22 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 062bb77d886f..e88f449e89e1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6497,6 +6497,7 @@  static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
 	if (th->syn) {
 		if (tcp_ecn_mode_accecn(tp)) {
 			send_accecn_reflector = true;
+			tp->syn_ect_rcv = TCP_SKB_CB(skb)->ip_dsfield & INET_ECN_MASK;
 			if (tp->rx_opt.accecn &&
 			    tp->saw_accecn_opt < TCP_ACCECN_OPT_COUNTER_SEEN) {
 				tp->saw_accecn_opt = tcp_accecn_option_init(skb,
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 4037a94fbe59..301606ff1708 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -775,16 +775,23 @@  struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
 		 */
 		if (!tcp_oow_rate_limited(sock_net(sk), skb,
 					  LINUX_MIB_TCPACKSKIPPEDSYNRECV,
-					  &tcp_rsk(req)->last_oow_ack_time) &&
-
-		    !inet_rtx_syn_ack(sk, req)) {
-			unsigned long expires = jiffies;
-
-			expires += reqsk_timeout(req, TCP_RTO_MAX);
-			if (!fastopen)
-				mod_timer_pending(&req->rsk_timer, expires);
-			else
-				req->rsk_timer.expires = expires;
+					  &tcp_rsk(req)->last_oow_ack_time)) {
+			if (tcp_rsk(req)->accecn_ok) {
+				tcp_rsk(req)->syn_ect_rcv = TCP_SKB_CB(skb)->ip_dsfield &
+							    INET_ECN_MASK;
+				if (tcp_accecn_ace(tcp_hdr(skb)) == 0x0)
+					tcp_accecn_fail_mode_set(tcp_sk(sk),
+								 TCP_ACCECN_ACE_FAIL_RECV);
+			}
+			if (!inet_rtx_syn_ack(sk, req)) {
+				unsigned long expires = jiffies;
+
+				expires += reqsk_timeout(req, TCP_RTO_MAX);
+				if (!fastopen)
+					mod_timer_pending(&req->rsk_timer, expires);
+				else
+					req->rsk_timer.expires = expires;
+			}
 		}
 		return NULL;
 	}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e5c361788a17..74ba08a33434 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -397,7 +397,7 @@  static void tcp_accecn_echo_syn_ect(struct tcphdr *th, u8 ect)
 }
 
 static void
-tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)
+tcp_ecn_make_synack(struct sock *sk, const struct request_sock *req, struct tcphdr *th)
 {
 	if (req->num_retrans < 1 || req->num_timeout < 1) {
 		if (tcp_rsk(req)->accecn_ok)
@@ -408,6 +408,7 @@  tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)
 		th->ae  = 0;
 		th->cwr = 0;
 		th->ece = 0;
+		tcp_accecn_fail_mode_set(tcp_sk(sk), TCP_ACCECN_ACE_FAIL_SEND);
 	}
 }
 
@@ -440,7 +441,7 @@  static void tcp_ecn_send(struct sock *sk, struct sk_buff *skb,
 	if (!tcp_ecn_mode_any(tp))
 		return;
 
-	if (!tcp_accecn_ace_fail_recv(tp))
+	if (!tcp_accecn_ace_fail_send(tp) && !tcp_accecn_ace_fail_recv(tp))
 		/* The CCA could change the ECT codepoint on the fly, reset it*/
 		__INET_ECN_xmit(sk, tp->ecn_flags & TCP_ECN_ECT_1);
 	if (tcp_ecn_mode_accecn(tp)) {
@@ -4052,7 +4053,7 @@  struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
 	memset(th, 0, sizeof(struct tcphdr));
 	th->syn = 1;
 	th->ack = 1;
-	tcp_ecn_make_synack(req, th);
+	tcp_ecn_make_synack((struct sock *)sk, req, th);
 	th->source = htons(ireq->ir_num);
 	th->dest = ireq->ir_rmt_port;
 	skb->mark = ireq->ir_mark;