From b66b621815341c46c87d2804ca1bf2ca1774e1b2 Mon Sep 17 00:00:00 2001 From: Abdul Kabbani Date: Fri, 24 Jan 2020 16:34:02 -0500 Subject: [PATCH] tcp: export count for rehash attempts Using IPv6 flow-label to swiftly route around avoid congested or disconnected network path can greatly improve TCP reliability. This patch adds SNMP counters and a OPT_STATS counter to track both host-level and connection-level statistics. Network administrators can use these counters to evaluate the impact of this new ability better. Export count for rehash attempts to 1) two SNMP counters: TcpTimeoutRehash (rehash due to timeouts), and TcpDuplicateDataRehash (rehash due to receiving duplicate packets) 2) Timestamping API SOF_TIMESTAMPING_OPT_STATS. Signed-off-by: Abdul Kabbani Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Kevin(Yudong) Yang Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/tcp.h | 2 ++ include/uapi/linux/snmp.h | 2 ++ include/uapi/linux/tcp.h | 1 + net/ipv4/proc.c | 2 ++ net/ipv4/tcp.c | 2 ++ net/ipv4/tcp_input.c | 4 +++- net/ipv4/tcp_timer.c | 6 ++++++ 7 files changed, 18 insertions(+), 1 deletion(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 4e2124607d325..1cf73e6f85ca8 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -386,6 +386,8 @@ struct tcp_sock { #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0 #endif + u16 timeout_rehash; /* Timeout-triggered rehash attempts */ + u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */ /* Receiver side RTT estimation */ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 7eee233e78d27..7d91f4debc483 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -285,6 +285,8 @@ enum LINUX_MIB_TCPRCVQDROP, /* TCPRcvQDrop */ LINUX_MIB_TCPWQUEUETOOBIG, /* TCPWqueueTooBig */ LINUX_MIB_TCPFASTOPENPASSIVEALTKEY, /* TCPFastOpenPassiveAltKey */ + LINUX_MIB_TCPTIMEOUTREHASH, /* TCPTimeoutRehash */ + LINUX_MIB_TCPDUPLICATEDATAREHASH, /* TCPDuplicateDataRehash */ __LINUX_MIB_MAX }; diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index d87184e673ca8..fd9eb8f6bcae3 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -311,6 +311,7 @@ enum { TCP_NLA_DSACK_DUPS, /* DSACK blocks received */ TCP_NLA_REORD_SEEN, /* reordering events seen */ TCP_NLA_SRTT, /* smoothed RTT in usecs */ + TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */ }; /* for TCP_MD5SIG socket option */ diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index cc90243ccf767..2580303249e23 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -289,6 +289,8 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPRcvQDrop", LINUX_MIB_TCPRCVQDROP), SNMP_MIB_ITEM("TCPWqueueTooBig", LINUX_MIB_TCPWQUEUETOOBIG), SNMP_MIB_ITEM("TCPFastOpenPassiveAltKey", LINUX_MIB_TCPFASTOPENPASSIVEALTKEY), + SNMP_MIB_ITEM("TcpTimeoutRehash", LINUX_MIB_TCPTIMEOUTREHASH), + SNMP_MIB_ITEM("TcpDuplicateDataRehash", LINUX_MIB_TCPDUPLICATEDATAREHASH), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2857c853e2fdc..484485ae74c26 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3337,6 +3337,7 @@ static size_t tcp_opt_stats_get_size(void) nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */ nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */ nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */ + nla_total_size(sizeof(u16)) + /* TCP_NLA_TIMEOUT_REHASH */ 0; } @@ -3391,6 +3392,7 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk) nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups); nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen); nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3); + nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, tp->timeout_rehash); return stats; } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 4915de65d278d..e8b840a4767e1 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4271,8 +4271,10 @@ static void tcp_rcv_spurious_retrans(struct sock *sk, const struct sk_buff *skb) * The receiver remembers and reflects via DSACKs. Leverage the * DSACK state and change the txhash to re-route speculatively. */ - if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq) + if (TCP_SKB_CB(skb)->seq == tcp_sk(sk)->duplicate_sack[0].start_seq) { sk_rethink_txhash(sk); + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPDUPLICATEDATAREHASH); + } } static void tcp_send_dupack(struct sock *sk, const struct sk_buff *skb) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 1097b438befe1..c3f26dcd6704e 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -223,6 +223,9 @@ static int tcp_write_timeout(struct sock *sk) dst_negative_advice(sk); } else { sk_rethink_txhash(sk); + tp->timeout_rehash++; + __NET_INC_STATS(sock_net(sk), + LINUX_MIB_TCPTIMEOUTREHASH); } retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; expired = icsk->icsk_retransmits >= retry_until; @@ -234,6 +237,9 @@ static int tcp_write_timeout(struct sock *sk) dst_negative_advice(sk); } else { sk_rethink_txhash(sk); + tp->timeout_rehash++; + __NET_INC_STATS(sock_net(sk), + LINUX_MIB_TCPTIMEOUTREHASH); } retry_until = net->ipv4.sysctl_tcp_retries2; -- 2.39.5