mptcp: mib: count MPJ with backup flag

commit 4dde0d72ccec500c60c798e036b852e013d6e124 upstream.

Without such counters, it is difficult to easily debug issues with MPJ
not having the backup flags on production servers.

This is not strictly a fix, but it eases to validate the following
patches without requiring to take packet traces, to query ongoing
connections with Netlink with admin permissions, or to guess by looking
at the behaviour of the packet scheduler. Also, the modification is self
contained, isolated, well controlled, and the increments are done just
after others, there from the beginning. It looks then safe, and helpful
to backport this.

Fixes: 4596a2c1b7f5 ("mptcp: allow creating non-backup subflows")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index c30405e7683370d3e3f422ac9a7b0c625348b1ae..7884217f33eb2f75ea76086c7f7fbea7106b0c1a 100644 (file)
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -19,7 +19,9 @@ static const struct snmp_mib mptcp_snmp_list[] = {
        SNMP_MIB_ITEM("MPTCPRetrans", MPTCP_MIB_RETRANSSEGS),
        SNMP_MIB_ITEM("MPJoinNoTokenFound", MPTCP_MIB_JOINNOTOKEN),
        SNMP_MIB_ITEM("MPJoinSynRx", MPTCP_MIB_JOINSYNRX),
+       SNMP_MIB_ITEM("MPJoinSynBackupRx", MPTCP_MIB_JOINSYNBACKUPRX),
        SNMP_MIB_ITEM("MPJoinSynAckRx", MPTCP_MIB_JOINSYNACKRX),
+       SNMP_MIB_ITEM("MPJoinSynAckBackupRx", MPTCP_MIB_JOINSYNACKBACKUPRX),
        SNMP_MIB_ITEM("MPJoinSynAckHMacFailure", MPTCP_MIB_JOINSYNACKMAC),
        SNMP_MIB_ITEM("MPJoinAckRx", MPTCP_MIB_JOINACKRX),
        SNMP_MIB_ITEM("MPJoinAckHMacFailure", MPTCP_MIB_JOINACKMAC),

diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 2704afd0dfe45249b1789d1c31732a982eafee65..66aa67f49d032c75e2821ed69be24b41e30a956a 100644 (file)
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -14,7 +14,9 @@ enum linux_mptcp_mib_field {
        MPTCP_MIB_RETRANSSEGS,          /* Segments retransmitted at the MPTCP-level */
        MPTCP_MIB_JOINNOTOKEN,          /* Received MP_JOIN but the token was not found */
        MPTCP_MIB_JOINSYNRX,            /* Received a SYN + MP_JOIN */
+       MPTCP_MIB_JOINSYNBACKUPRX,      /* Received a SYN + MP_JOIN + backup flag */
        MPTCP_MIB_JOINSYNACKRX,         /* Received a SYN/ACK + MP_JOIN */
+       MPTCP_MIB_JOINSYNACKBACKUPRX,   /* Received a SYN/ACK + MP_JOIN + backup flag */
        MPTCP_MIB_JOINSYNACKMAC,        /* HMAC was wrong on SYN/ACK + MP_JOIN */
        MPTCP_MIB_JOINACKRX,            /* Received an ACK + MP_JOIN */
        MPTCP_MIB_JOINACKMAC,           /* HMAC was wrong on ACK + MP_JOIN */

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 616929fa29924c9ce5e776b805dd7376965e13a9..a90cf6bfb62cd0ee3a246fb8cea2b2ce76fa1b8f 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -168,6 +168,9 @@ static int subflow_check_req(struct request_sock *req,
                        return 0;
        } else if (opt_mp_join) {
                SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
+
+               if (mp_opt.backup)
+                       SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNBACKUPRX);
        }
 
        if (opt_mp_capable && listener->request_mptcp) {
@@ -577,6 +580,9 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
                subflow->mp_join = 1;
                MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
 
+               if (subflow->backup)
+                       MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKBACKUPRX);
+
                if (subflow_use_different_dport(msk, sk)) {
                        pr_debug("synack inet_dport=%d %d",
                                 ntohs(inet_sk(sk)->inet_dport),