net/tcp_fastopen: Add snmp counter for blackhole detection

This counter records the number of times the firewall blackhole issue is
detected and active TFO is disabled.

Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tcp.h b/include/net/tcp.h
index c1abc2abbdcbf2d13f7fb6e0b6d8fae719aceddf..da28bef1d82b6773bbfcf7c7eafebb7a4932f25b 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1507,7 +1507,7 @@ struct tcp_fastopen_context {
 };
 
 extern unsigned int sysctl_tcp_fastopen_blackhole_timeout;
-void tcp_fastopen_active_disable(void);
+void tcp_fastopen_active_disable(struct sock *sk);
 bool tcp_fastopen_active_should_disable(struct sock *sk);
 void tcp_fastopen_active_disable_ofo_check(struct sock *sk);
 void tcp_fastopen_active_timeout_reset(void);

diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index cec0e171d20caea2f188c06a9924f886b0daaa85..95cffcb21dfdba7c974706131d0f43e21435e82d 100644 (file)
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -259,6 +259,7 @@ enum
        LINUX_MIB_TCPFASTOPENPASSIVEFAIL,       /* TCPFastOpenPassiveFail */
        LINUX_MIB_TCPFASTOPENLISTENOVERFLOW,    /* TCPFastOpenListenOverflow */
        LINUX_MIB_TCPFASTOPENCOOKIEREQD,        /* TCPFastOpenCookieReqd */
+       LINUX_MIB_TCPFASTOPENBLACKHOLE,         /* TCPFastOpenBlackholeDetect */
        LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES, /* TCPSpuriousRtxHostQueues */
        LINUX_MIB_BUSYPOLLRXPACKETS,            /* BusyPollRxPackets */
        LINUX_MIB_TCPAUTOCORKING,               /* TCPAutoCorking */

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 4ccbf464d1acf5f433dd2a0768691f5d22e3033d..fa44e752a9a3f8eb9957314149ae15e6df10465a 100644 (file)
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -281,6 +281,7 @@ static const struct snmp_mib snmp4_net_list[] = {
        SNMP_MIB_ITEM("TCPFastOpenPassiveFail", LINUX_MIB_TCPFASTOPENPASSIVEFAIL),
        SNMP_MIB_ITEM("TCPFastOpenListenOverflow", LINUX_MIB_TCPFASTOPENLISTENOVERFLOW),
        SNMP_MIB_ITEM("TCPFastOpenCookieReqd", LINUX_MIB_TCPFASTOPENCOOKIEREQD),
+       SNMP_MIB_ITEM("TCPFastOpenBlackhole", LINUX_MIB_TCPFASTOPENBLACKHOLE),
        SNMP_MIB_ITEM("TCPSpuriousRtxHostQueues", LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES),
        SNMP_MIB_ITEM("BusyPollRxPackets", LINUX_MIB_BUSYPOLLRXPACKETS),
        SNMP_MIB_ITEM("TCPAutoCorking", LINUX_MIB_TCPAUTOCORKING),

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index ff2d30ffc6f3e0b2d817deff8d93b07ebba9044e..4af82b914dd4bbdc47e37cf1cf70f206bd186db5 100644 (file)
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -410,10 +410,11 @@ static unsigned long tfo_active_disable_stamp __read_mostly;
 /* Disable active TFO and record current jiffies and
  * tfo_active_disable_times
  */
-void tcp_fastopen_active_disable(void)
+void tcp_fastopen_active_disable(struct sock *sk)
 {
        atomic_inc(&tfo_active_disable_times);
        tfo_active_disable_stamp = jiffies;
+       NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENBLACKHOLE);
 }
 
 /* Reset tfo_active_disable_times to 0 */
@@ -469,7 +470,7 @@ void tcp_fastopen_active_disable_ofo_check(struct sock *sk)
                if (p && !rb_next(p)) {
                        skb = rb_entry(p, struct sk_buff, rbnode);
                        if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
-                               tcp_fastopen_active_disable();
+                               tcp_fastopen_active_disable(sk);
                                return;
                        }
                }

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9f342a67dc741d2fffe45c123b31b4af9ae39e12..5af2f04f885914491a7116c20056b3d2188d2d7d 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5307,7 +5307,7 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
                         */
                        if (tp->syn_fastopen && !tp->data_segs_in &&
                            sk->sk_state == TCP_ESTABLISHED)
-                               tcp_fastopen_active_disable();
+                               tcp_fastopen_active_disable(sk);
                        tcp_send_challenge_ack(sk, skb);
                }
                goto discard;
@@ -6061,7 +6061,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
                    after(TCP_SKB_CB(skb)->end_seq - th->fin, tp->rcv_nxt)) {
                        /* Receive out of order FIN after close() */
                        if (tp->syn_fastopen && th->fin)
-                               tcp_fastopen_active_disable();
+                               tcp_fastopen_active_disable(sk);
                        tcp_done(sk);
                        NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
                        return 1;