net: sctp: dynamically enable or disable pf state

As we all know, the value of pf_retrans >= max_retrans_path can
disable pf state. The variables of pf_retrans and max_retrans_path
can be changed by the userspace application.

Sometimes the user expects to disable pf state while the 2
variables are changed to enable pf state. So it is necessary to
introduce a new variable to disable pf state.

According to the suggestions from Vlad Yasevich, extra1 and extra2
are removed. The initialization of pf_enable is added.

Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Zhu Yanjun <zyjzyj2000@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 2ea4c45..5de632e 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1723,6 +1723,25 @@ addip_enable - BOOLEAN
 
        Default: 0
 
+pf_enable - INTEGER
+       Enable or disable pf (pf is short for potentially failed) state. A value
+       of pf_retrans > path_max_retrans also disables pf state. That is, one of
+       both pf_enable and pf_retrans > path_max_retrans can disable pf state.
+       Since pf_retrans and path_max_retrans can be changed by userspace
+       application, sometimes user expects to disable pf state by the value of
+       pf_retrans > path_max_retrans, but occasionally the value of pf_retrans
+       or path_max_retrans is changed by the user application, this pf state is
+       enabled. As such, it is necessary to add this to dynamically enable
+       and disable pf state. See:
+       https://datatracker.ietf.org/doc/draft-ietf-tsvwg-sctp-failover for
+       details.
+
+       1: Enable pf.
+
+       0: Disable pf.
+
+       Default: 1
+
 addip_noauth_enable - BOOLEAN
        Dynamic Address Reconfiguration (ADD-IP) requires the use of
        authentication to protect the operations of adding or removing new
@@ -1799,7 +1818,9 @@ pf_retrans - INTEGER
        having to reduce path_max_retrans to a very low value.  See:
        http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt
        for details.  Note also that a value of pf_retrans > path_max_retrans
-       disables this feature
+       disables this feature. Since both pf_retrans and path_max_retrans can
+       be changed by userspace application, a variable pf_enable is used to
+       disable pf state.
 
        Default: 0
 

diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h
index 8ba379f..c501d67 100644 (file)
--- a/include/net/netns/sctp.h
+++ b/include/net/netns/sctp.h
@@ -88,6 +88,13 @@ struct netns_sctp {
         */
        int pf_retrans;
 
+       /*
+        * Disable Potentially-Failed feature, the feature is enabled by default
+        * pf_enable    -  0  : disable pf
+        *              - >0  : enable pf
+        */
+       int pf_enable;
+
        /*
         * Policy for preforming sctp/socket accounting
         * 0   - do socket level accounting, all assocs share sk_sndbuf

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 6c2c0ac..010aced 100644 (file)
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1223,6 +1223,9 @@ static int __net_init sctp_defaults_init(struct net *net)
        /* Max.Burst                - 4 */
        net->sctp.max_burst                     = SCTP_DEFAULT_MAX_BURST;
 
+       /* Enable pf state by default */
+       net->sctp.pf_enable = 1;
+
        /* Association.Max.Retrans  - 10 attempts
         * Path.Max.Retrans         - 5  attempts (per destination address)
         * Max.Init.Retransmits     - 8  attempts

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 6098d4c..05cd164 100644 (file)
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -477,6 +477,8 @@ static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
                                         struct sctp_transport *transport,
                                         int is_hb)
 {
+       struct net *net = sock_net(asoc->base.sk);
+
        /* The check for association's overall error counter exceeding the
         * threshold is done in the state function.
         */
@@ -503,7 +505,8 @@ static void sctp_do_8_2_transport_strike(sctp_cmd_seq_t *commands,
         * is SCTP_ACTIVE, then mark this transport as Partially Failed,
         * see SCTP Quick Failover Draft, section 5.1
         */
-       if ((transport->state == SCTP_ACTIVE) &&
+       if (net->sctp.pf_enable &&
+          (transport->state == SCTP_ACTIVE) &&
           (asoc->pf_retrans < transport->pathmaxrxt) &&
           (transport->error_count > asoc->pf_retrans)) {
 

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 26d50c5..ccbfc93 100644 (file)
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -308,6 +308,13 @@ static struct ctl_table sctp_net_table[] = {
                .extra1         = &max_autoclose_min,
                .extra2         = &max_autoclose_max,
        },
+       {
+               .procname       = "pf_enable",
+               .data           = &init_net.sctp.pf_enable,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
 
        { /* sentinel */ }
 };