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>
[ Conflicts in subflow.c because the context has changed in
  commit b3ea6b272d79 ("mptcp: consolidate initial ack seq generation")
  which is not in this version. This commit is unrelated to this
  modification. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index 8d1c67b9359115aaa6e8e63c13f270584948a247..c2fadfcfd6d6a4edca20d118433c79aaad56b014 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 2966fcb6548bac6ba539183c428ec16e9b77a896..90025acdcf7245d9ad28a1939f7453e6a981898a 100644 (file)
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -12,7 +12,9 @@ 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 2fdc7b1d2f3285ac352323f65f3dd6f63e165a77..90e7a46a6d2f85a524fe6e869c0f9dab56f11730 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -163,6 +163,9 @@ 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) {
@@ -462,6 +465,9 @@ 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(mptcp_sk(parent), sk)) {
                        pr_debug("synack inet_dport=%d %d",
                                 ntohs(inet_sk(sk)->inet_dport),