[ovs-dev] [PATCH 2/4] Native tunnel: Add tnl/neigh/ageing command.

Gaëtan Rivet grive at u256.net
Wed Nov 3 19:01:46 UTC 2021


On Tue, Nov 2, 2021, at 18:12, Paolo Valerio wrote:
> with the command is now possible to change the ageing time of the
> cache entries.
>
> For the existing entries the ageing time is updated only if the
> current expiration is greater than the new one. In any case, the next
> refresh will set it to the new value.
>
> This is intended mostly for debugging purpose.
>
> Signed-off-by: Paolo Valerio <pvalerio at redhat.com>
> ---
>  NEWS                            |    3 ++
>  lib/tnl-neigh-cache.c           |   77 ++++++++++++++++++++++++++++++++++-----
>  ofproto/ofproto-tnl-unixctl.man |    9 +++++
>  tests/tunnel-push-pop-ipv6.at   |   30 +++++++++++++++
>  tests/tunnel-push-pop.at        |   30 +++++++++++++++
>  5 files changed, 140 insertions(+), 9 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index 90f4b1590..148dd5d61 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -10,6 +10,9 @@ Post-v2.16.0
>         limiting behavior.
>       * Add hardware offload support for matching IPv4/IPv6 frag types
>         (experimental).
> +   - Native tunnel:
> +     * Added new ovs-appctl tnl/neigh/ageing to read/write the neigh ageing
> +       time.
> 
> 
>  v2.16.0 - 16 Aug 2021
> diff --git a/lib/tnl-neigh-cache.c b/lib/tnl-neigh-cache.c
> index 2769e5c3d..8eacaccd8 100644
> --- a/lib/tnl-neigh-cache.c
> +++ b/lib/tnl-neigh-cache.c
> @@ -47,6 +47,7 @@
> 
>  /* In milliseconds */
>  #define NEIGH_ENTRY_DEFAULT_IDLE_TIME  (15 * 60 * 1000)
> +#define NEIGH_ENTRY_MAX_AGEING_TIME    (3600 * 1000)

Same remark, using _MS suffix would be nice.

> 
>  struct tnl_neigh_entry {
>      struct cmap_node cmap_node;
> @@ -58,6 +59,7 @@ struct tnl_neigh_entry {
> 
>  static struct cmap table = CMAP_INITIALIZER;
>  static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER;
> +static atomic_uint32_t neigh_ageing;
> 
>  static uint32_t
>  tnl_neigh_hash(const struct in6_addr *ip)
> @@ -75,6 +77,15 @@ tnl_neigh_expired(struct tnl_neigh_entry *neigh)
>      return expired <= time_msec();
>  }
> 
> +static uint32_t
> +tnl_neigh_get_ageing(void)
> +{
> +    unsigned int ageing;
> +
> +    atomic_read_relaxed(&neigh_ageing, &ageing);
> +    return ageing;
> +}
> +
>  static struct tnl_neigh_entry *
>  tnl_neigh_lookup__(const char br_name[IFNAMSIZ], const struct in6_addr 
> *dst)
>  {
> @@ -89,7 +100,7 @@ tnl_neigh_lookup__(const char br_name[IFNAMSIZ], 
> const struct in6_addr *dst)
>              }
> 
>              atomic_store_relaxed(&neigh->expires, time_msec() +
> -                                 NEIGH_ENTRY_DEFAULT_IDLE_TIME);
> +                                 tnl_neigh_get_ageing());
>              return neigh;
>          }
>      }
> @@ -134,7 +145,7 @@ tnl_neigh_set__(const char name[IFNAMSIZ], const 
> struct in6_addr *dst,
>      if (neigh) {
>          if (eth_addr_equals(neigh->mac, mac)) {
>              atomic_store_relaxed(&neigh->expires, time_msec() +
> -                                 NEIGH_ENTRY_DEFAULT_IDLE_TIME);
> +                                 tnl_neigh_get_ageing());
>              ovs_mutex_unlock(&mutex);
>              return;
>          }
> @@ -147,7 +158,7 @@ tnl_neigh_set__(const char name[IFNAMSIZ], const 
> struct in6_addr *dst,
>      neigh->ip = *dst;
>      neigh->mac = mac;
>      atomic_store_relaxed(&neigh->expires, time_msec() +
> -                         NEIGH_ENTRY_DEFAULT_IDLE_TIME);
> +                         tnl_neigh_get_ageing());
>      ovs_strlcpy(neigh->br_name, name, sizeof neigh->br_name);
>      cmap_insert(&table, &neigh->cmap_node, tnl_neigh_hash(&neigh->ip));
>      ovs_mutex_unlock(&mutex);
> @@ -273,6 +284,43 @@ tnl_neigh_cache_flush(struct unixctl_conn *conn, 
> int argc OVS_UNUSED,
>      unixctl_command_reply(conn, "OK");
>  }
> 
> +static void
> +tnl_neigh_cache_ageing(struct unixctl_conn *conn, int argc,
> +                        const char *argv[], void *aux OVS_UNUSED)
> +{
> +    long long int new_exp, curr_exp;
> +    struct tnl_neigh_entry *neigh;
> +    uint32_t ageing;
> +
> +    if (argc == 1) {
> +        struct ds ds = DS_EMPTY_INITIALIZER;
> +        ds_put_format(&ds, "%"PRIu32, tnl_neigh_get_ageing() / 1000);
> +        unixctl_command_reply(conn, ds_cstr(&ds));
> +        ds_destroy(&ds);
> +
> +        return;
> +    }
> +
> +    if (!ovs_scan(argv[1], "%"SCNu32, &ageing) ||
> +        !ageing || ageing > NEIGH_ENTRY_MAX_AGEING_TIME) {

ageing is provided in seconds, while NEIGH_ENTRY_MAX_AGEING_TIME is
in milliseconds right?

> +        unixctl_command_reply_error(conn, "bad ageing value");
> +        return;
> +    }
> +
> +    ageing *= 1000;
> +    atomic_store_relaxed(&neigh_ageing, ageing);

Release here with acquire in tnl_neigh_get_ageing() might be needed.

> +    new_exp = time_msec() + ageing;
> +
> +    CMAP_FOR_EACH (neigh, cmap_node, &table) {
> +        atomic_read_relaxed(&neigh->expires, &curr_exp);
> +        if (new_exp < curr_exp) {
> +            atomic_store_relaxed(&neigh->expires, new_exp);
> +        }

Potential re-ordering issue between read and write seems more acute here.
The explicit acquire / release ordering should probably be used.

> +    }
> +
> +    unixctl_command_reply(conn, "OK");
> +}
> +
>  static int
>  lookup_any(const char *host_name, struct in6_addr *address)
>  {
> @@ -347,10 +395,21 @@ tnl_neigh_cache_show(struct unixctl_conn *conn, 
> int argc OVS_UNUSED,
>  void
>  tnl_neigh_cache_init(void)
>  {
> -    unixctl_command_register("tnl/arp/show", "", 0, 0, 
> tnl_neigh_cache_show, NULL);
> -    unixctl_command_register("tnl/arp/set", "BRIDGE IP MAC", 3, 3, 
> tnl_neigh_cache_add, NULL);
> -    unixctl_command_register("tnl/arp/flush", "", 0, 0, 
> tnl_neigh_cache_flush, NULL);
> -    unixctl_command_register("tnl/neigh/show", "", 0, 0, 
> tnl_neigh_cache_show, NULL);
> -    unixctl_command_register("tnl/neigh/set", "BRIDGE IP MAC", 3, 3, 
> tnl_neigh_cache_add, NULL);
> -    unixctl_command_register("tnl/neigh/flush", "", 0, 0, 
> tnl_neigh_cache_flush, NULL);
> +    atomic_init(&neigh_ageing, NEIGH_ENTRY_DEFAULT_IDLE_TIME);
> +    unixctl_command_register("tnl/arp/show", "", 0, 0,
> +                             tnl_neigh_cache_show, NULL);
> +    unixctl_command_register("tnl/arp/set", "BRIDGE IP MAC", 3, 3,
> +                             tnl_neigh_cache_add, NULL);
> +    unixctl_command_register("tnl/arp/flush", "", 0, 0,
> +                             tnl_neigh_cache_flush, NULL);
> +    unixctl_command_register("tnl/arp/ageing", "[SECS]", 0, 1,
> +                             tnl_neigh_cache_ageing, NULL);
> +    unixctl_command_register("tnl/neigh/show", "", 0, 0,
> +                             tnl_neigh_cache_show, NULL);
> +    unixctl_command_register("tnl/neigh/set", "BRIDGE IP MAC", 3, 3,
> +                             tnl_neigh_cache_add, NULL);
> +    unixctl_command_register("tnl/neigh/flush", "", 0, 0,
> +                             tnl_neigh_cache_flush, NULL);
> +    unixctl_command_register("tnl/neigh/ageing", "[SECS]", 0, 1,
> +                             tnl_neigh_cache_ageing, NULL);
>  }
> diff --git a/ofproto/ofproto-tnl-unixctl.man 
> b/ofproto/ofproto-tnl-unixctl.man
> index c70cca539..5c2ad4843 100644
> --- a/ofproto/ofproto-tnl-unixctl.man
> +++ b/ofproto/ofproto-tnl-unixctl.man
> @@ -27,6 +27,15 @@ to \fImac\fR.
>  .IP "\fBtnl/arp/flush\fR"
>  Flush ARP table.
>  .
> +.IP "\fBtnl/neigh/ageing [\fIseconds\fB]\fR"
> +.IP "\fBtnl/arp/ageing [\fIseconds\fB]\fR"
> +Changes the ageing time. The accepted values of \fIseconds\fR are
> +between 1 and 3600. The new entries will get the value as specified in
> +\fIseconds\fR. For the existing entries, the ageing time is updated
> +only if the current expiration is greater than \fIseconds\fR.
> +.IP
> +If used without arguments, it prints the current ageing value.
> +.
>  .IP "\fBtnl/egress_port_range [num1] [num2]\fR"
>  Set range for UDP source port used for UDP based Tunnels. For
>  example VxLAN. If case of zero arguments this command prints
> diff --git a/tests/tunnel-push-pop-ipv6.at 
> b/tests/tunnel-push-pop-ipv6.at
> index 59723e63b..766a4bcf8 100644
> --- a/tests/tunnel-push-pop-ipv6.at
> +++ b/tests/tunnel-push-pop-ipv6.at
> @@ -255,6 +255,36 @@ AT_CHECK([cat p0.pcap.txt | grep 
> 93aa55aa55000086dd6000000000203aff2001cafe | un
>  
> 3333ff000093aa55aa55000086dd6000000000203aff2001cafe000000000000000000000088ff0200000000000000000001ff00009387004d46000000002001cafe0000000000000000000000930101aa55aa550000
>  ])
> 
> +dnl Set the ageing time to 5 seconds
> +AT_CHECK([ovs-appctl tnl/neigh/ageing 5], [0], [OK
> +])
> +
> +dnl Read the current ageing time
> +AT_CHECK([ovs-appctl tnl/neigh/ageing], [0], [5
> +])
> +
> +dnl Add an entry
> +AT_CHECK([ovs-appctl tnl/neigh/set br0 2001:cafe::92 
> aa:bb:cc:00:00:01], [0], [OK
> +])
> +
> +AT_CHECK([ovs-appctl tnl/neigh/show | grep br0 | sort], [0], [dnl
> +2001:cafe::92                                 aa:bb:cc:00:00:01   br0
> +])
> +
> +ovs-appctl time/warp 5000
> +
> +dnl Check the entry has been removed
> +AT_CHECK([ovs-appctl tnl/neigh/show | grep br0 | sort], [0], [dnl
> +])
> +
> +dnl Restore the ageing time to 900s (default)
> +AT_CHECK([ovs-appctl tnl/neigh/ageing 900], [0], [OK
> +])
> +
> +dnl Read the current ageing time
> +AT_CHECK([ovs-appctl tnl/neigh/ageing], [0], [900
> +])
> +
>  dnl Check ARP Snoop
>  AT_CHECK([ovs-appctl netdev-dummy/receive p0 
> 'in_port(1),eth(src=f8:bc:12:44:34:c8,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:cafe::92,dst=2001:cafe::88,label=0,proto=58,tclass=0,hlimit=255,frag=no),icmpv6(type=136,code=0),nd(target=2001:cafe::92,sll=00:00:00:00:00:00,tll=f8:bc:12:44:34:c8)'])
> 
> diff --git a/tests/tunnel-push-pop.at b/tests/tunnel-push-pop.at
> index 12fc1ef91..385d14ab3 100644
> --- a/tests/tunnel-push-pop.at
> +++ b/tests/tunnel-push-pop.at
> @@ -270,6 +270,36 @@ AT_CHECK([cat p0.pcap.txt | grep 101025d | uniq], 
> [0], [dnl
>  
> ffffffffffffaa55aa55000008060001080006040001aa55aa550000010102580000000000000101025d
>  ])
> 
> +dnl Set the ageing time to 5 seconds
> +AT_CHECK([ovs-appctl tnl/neigh/ageing 5], [0], [OK
> +])
> +
> +dnl Read the current ageing time
> +AT_CHECK([ovs-appctl tnl/neigh/ageing], [0], [5
> +])
> +
> +dnl Add an entry
> +AT_CHECK([ovs-appctl tnl/neigh/set br0 1.1.2.92 aa:bb:cc:00:00:01], 
> [0], [OK
> +])
> +
> +AT_CHECK([ovs-appctl tnl/neigh/show | grep br0 | sort], [0], [dnl
> +1.1.2.92                                      aa:bb:cc:00:00:01   br0
> +])
> +
> +ovs-appctl time/warp 5000
> +
> +dnl Check the entry has been removed
> +AT_CHECK([ovs-appctl tnl/neigh/show | grep br0 | sort], [0], [dnl
> +])
> +
> +dnl Restore the ageing time to 900s (default)
> +AT_CHECK([ovs-appctl tnl/neigh/ageing 900], [0], [OK
> +])
> +
> +dnl Read the current ageing time
> +AT_CHECK([ovs-appctl tnl/neigh/ageing], [0], [900
> +])
> +
>  dnl Check ARP Snoop
>  AT_CHECK([ovs-appctl netdev-dummy/receive p0 
> 'recirc_id(0),in_port(1),eth(src=f8:bc:12:44:34:c8,dst=ff:ff:ff:ff:ff:ff),eth_type(0x0806),arp(sip=1.1.2.92,tip=1.1.2.88,op=2,sha=f8:bc:12:44:34:c8,tha=00:00:00:00:00:00)'])
> 
>
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> dev at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev

-- 
Gaetan Rivet


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