tcp: accecn: add tcpi_ecn_mode and tcpi_option2 in tcp_info

Add 2-bit tcpi_ecn_mode feild within tcp_info to indicate which ECN
mode is negotiated: ECN_MODE_DISABLED, ECN_MODE_RFC3168, ECN_MODE_ACCECN,
or ECN_MODE_PENDING. This is done by utilizing available bits from
tcpi_accecn_opt_seen (reduced from 16 bits to 2 bits) and
tcpi_accecn_fail_mode (reduced from 16 bits to 4 bits).

Also, an extra 24-bit tcpi_options2 field is identified to represent
newer options and connection features, as all 8 bits of tcpi_options
field have been used.

Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Co-developed-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-14-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/net/tcp_ecn.h b/include/net/tcp_ecn.h
index e01653bbf181b3960b393f7651630f9219d1e58d..e9a933641636e11902a84a595672cd56a551f305 100644 (file)
--- a/include/net/tcp_ecn.h
+++ b/include/net/tcp_ecn.h
@@ -67,12 +67,6 @@ static inline void tcp_ecn_withdraw_cwr(struct tcp_sock *tp)
        tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
 }
 
-/* tp->accecn_fail_mode */
-#define TCP_ACCECN_ACE_FAIL_SEND       BIT(0)
-#define TCP_ACCECN_ACE_FAIL_RECV       BIT(1)
-#define TCP_ACCECN_OPT_FAIL_SEND       BIT(2)
-#define TCP_ACCECN_OPT_FAIL_RECV       BIT(3)
-
 static inline bool tcp_accecn_ace_fail_send(const struct tcp_sock *tp)
 {
        return tp->accecn_fail_mode & TCP_ACCECN_ACE_FAIL_SEND;
@@ -98,11 +92,6 @@ static inline void tcp_accecn_fail_mode_set(struct tcp_sock *tp, u8 mode)
        tp->accecn_fail_mode |= mode;
 }
 
-#define TCP_ACCECN_OPT_NOT_SEEN                0x0
-#define TCP_ACCECN_OPT_EMPTY_SEEN      0x1
-#define TCP_ACCECN_OPT_COUNTER_SEEN    0x2
-#define TCP_ACCECN_OPT_FAIL_SEEN       0x3
-
 static inline u8 tcp_accecn_ace(const struct tcphdr *th)
 {
        return (th->ae << 2) | (th->cwr << 1) | th->ece;

diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index dce3113787a71bbfc2f2674cdfbd61d7cad40029..03772dd4d39927f460681dd9ce71431abb8e76a5 100644 (file)
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -226,6 +226,24 @@ enum tcp_ca_state {
 #define TCPF_CA_Loss   (1<<TCP_CA_Loss)
 };
 
+/* Values for tcpi_ecn_mode after negotiation */
+#define TCPI_ECN_MODE_DISABLED         0x0
+#define TCPI_ECN_MODE_RFC3168          0x1
+#define TCPI_ECN_MODE_ACCECN           0x2
+#define TCPI_ECN_MODE_PENDING          0x3
+
+/* Values for accecn_opt_seen */
+#define TCP_ACCECN_OPT_NOT_SEEN                0x0
+#define TCP_ACCECN_OPT_EMPTY_SEEN      0x1
+#define TCP_ACCECN_OPT_COUNTER_SEEN    0x2
+#define TCP_ACCECN_OPT_FAIL_SEEN       0x3
+
+/* Values for accecn_fail_mode */
+#define TCP_ACCECN_ACE_FAIL_SEND       BIT(0)
+#define TCP_ACCECN_ACE_FAIL_RECV       BIT(1)
+#define TCP_ACCECN_OPT_FAIL_SEND       BIT(2)
+#define TCP_ACCECN_OPT_FAIL_RECV       BIT(3)
+
 struct tcp_info {
        __u8    tcpi_state;
        __u8    tcpi_ca_state;
@@ -316,15 +334,17 @@ struct tcp_info {
                                         * in milliseconds, including any
                                         * unfinished recovery.
                                         */
-       __u32   tcpi_received_ce;    /* # of CE marks received */
+       __u32   tcpi_received_ce;    /* # of CE marked segments received */
        __u32   tcpi_delivered_e1_bytes;  /* Accurate ECN byte counters */
        __u32   tcpi_delivered_e0_bytes;
        __u32   tcpi_delivered_ce_bytes;
        __u32   tcpi_received_e1_bytes;
        __u32   tcpi_received_e0_bytes;
        __u32   tcpi_received_ce_bytes;
-       __u16   tcpi_accecn_fail_mode;
-       __u16   tcpi_accecn_opt_seen;
+       __u32   tcpi_ecn_mode:2,
+               tcpi_accecn_opt_seen:2,
+               tcpi_accecn_fail_mode:4,
+               tcpi_options2:24;
 };
 
 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 49f1029b5f8b6754d78159071f639cb96b81d585..6ce03a9adb4a97f554bd6b6cf887f4ad9dbfe5c3 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4373,6 +4373,14 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
        if (tp->rto_stamp)
                info->tcpi_total_rto_time += tcp_clock_ms() - tp->rto_stamp;
 
+       if (tcp_ecn_disabled(tp))
+               info->tcpi_ecn_mode = TCPI_ECN_MODE_DISABLED;
+       else if (tcp_ecn_mode_rfc3168(tp))
+               info->tcpi_ecn_mode = TCPI_ECN_MODE_RFC3168;
+       else if (tcp_ecn_mode_accecn(tp))
+               info->tcpi_ecn_mode = TCPI_ECN_MODE_ACCECN;
+       else if (tcp_ecn_mode_pending(tp))
+               info->tcpi_ecn_mode = TCPI_ECN_MODE_PENDING;
        info->tcpi_accecn_fail_mode = tp->accecn_fail_mode;
        info->tcpi_accecn_opt_seen = tp->saw_accecn_opt;
        info->tcpi_received_ce = tp->received_ce;