[ovs-dev] [PATCH v2] OVN: introduce mac_prefix support to IPAM

Lorenzo Bianconi lorenzo.bianconi at redhat.com
Fri Oct 26 16:20:44 UTC 2018


Add the possibility to specify a given mac address prefix for
dynamically generated mac address. Mac address prefix can be
specified in nbdb NB_Global table, options:mac_prefix=<mac_prefix>
This patch fix a possible issue of L2 address duplication if
multiple OVN deployments share a single broadcast domain

Acked-by: Mark Michelson <mmichels at redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
---
Changes since v1:
- use a global definition for mac_prefix
---
 ovn/northd/ovn-northd.c | 37 ++++++++++++++++++++++++++++++++++---
 ovn/ovn-nb.xml          |  5 +++++
 tests/ovn.at            | 17 +++++++++++++++++
 3 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index 439651f80..816c72311 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -68,6 +68,7 @@ static const char *unixctl_path;
 /* MAC address management (macam) table of "struct eth_addr"s, that holds the
  * MAC addresses allocated by the OVN ipam module. */
 static struct hmap macam = HMAP_INITIALIZER(&macam);
+static struct eth_addr mac_prefix;
 
 #define MAX_OVN_TAGS 4096
 
@@ -922,10 +923,17 @@ ipam_insert_mac(struct eth_addr *ea, bool check)
     }
 
     uint64_t mac64 = eth_addr_to_uint64(*ea);
+    uint64_t prefix;
+
+    if (!eth_addr_is_zero(mac_prefix)) {
+        prefix = eth_addr_to_uint64(mac_prefix);
+    } else {
+        prefix = MAC_ADDR_PREFIX;
+    }
     /* If the new MAC was not assigned by this address management system or
      * check is true and the new MAC is a duplicate, do not insert it into the
      * macam hmap. */
-    if (((mac64 ^ MAC_ADDR_PREFIX) >> 24)
+    if (((mac64 ^ prefix) >> 24)
         || (check && ipam_is_duplicate_mac(ea, mac64, true))) {
         return;
     }
@@ -1036,7 +1044,11 @@ ipam_get_unused_mac(void)
     for (i = 0; i < MAC_ADDR_SPACE - 1; i++) {
         /* The tentative MAC's suffix will be in the interval (1, 0xfffffe). */
         mac_addr_suffix = ((last_mac + i) % (MAC_ADDR_SPACE - 1)) + 1;
-        mac64 = MAC_ADDR_PREFIX | mac_addr_suffix;
+        if (!eth_addr_is_zero(mac_prefix)) {
+            mac64 =  eth_addr_to_uint64(mac_prefix) | mac_addr_suffix;
+        } else {
+            mac64 = MAC_ADDR_PREFIX | mac_addr_suffix;
+        }
         eth_addr_from_uint64(mac64, &mac);
         if (!ipam_is_duplicate_mac(&mac, mac64, false)) {
             last_mac = mac_addr_suffix;
@@ -1107,7 +1119,15 @@ dynamic_mac_changed(const char *lsp_addresses,
    }
 
    uint64_t mac64 = eth_addr_to_uint64(update->current_addresses.ea);
-   if ((mac64 ^ MAC_ADDR_PREFIX) >> 24) {
+   uint64_t prefix;
+
+   if (!eth_addr_is_zero(mac_prefix)) {
+       prefix = eth_addr_to_uint64(mac_prefix);
+   } else {
+       prefix = MAC_ADDR_PREFIX;
+   }
+
+   if ((mac64 ^ prefix) >> 24) {
        return DYNAMIC;
    } else {
        return NONE;
@@ -7141,6 +7161,17 @@ ovnnb_db_run(struct northd_context *ctx,
     sbrec_sb_global_set_options(sb, &nb->options);
     sb_loop->next_cfg = nb->nb_cfg;
 
+    const char *mac_addr_prefix = smap_get(&nb->options, "mac_prefix");
+    if (mac_addr_prefix) {
+        struct eth_addr addr;
+
+        memset(&addr, 0, sizeof addr);
+        if (ovs_scan(mac_addr_prefix, "%"SCNx8":%"SCNx8":%"SCNx8,
+                     &addr.ea[0], &addr.ea[1], &addr.ea[2])) {
+            mac_prefix = addr;
+        }
+    }
+
     cleanup_macam(&macam);
 }
 
diff --git a/ovn/ovn-nb.xml b/ovn/ovn-nb.xml
index c0739fe57..f309b3b86 100644
--- a/ovn/ovn-nb.xml
+++ b/ovn/ovn-nb.xml
@@ -102,6 +102,11 @@
           tunnel interfaces.
         </column>
       </group>
+
+      <column name="options" key="mac_prefix">
+        Configure a given OUI to be used as prefix when L2 address is
+        dynamically assigned, e.g. <code>00:11:22</code>
+      </column>
     </group>
 
     <group title="Connection Options">
diff --git a/tests/ovn.at b/tests/ovn.at
index 8825beca3..e512f94aa 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -5616,6 +5616,23 @@ AT_CHECK([ovn-nbctl get Logical-Switch-Port p41 dynamic_addresses], [0],
          ["f0:00:00:00:10:2b 192.168.1.3"
 ])
 
+# define a mac address prefix
+ovn-nbctl ls-add sw6
+ovn-nbctl --wait=hv set NB_Global . options:mac_prefix="00:11:22:33:44:55"
+ovn-nbctl --wait=sb set Logical-Switch sw6 other_config:subnet=192.168.100.0/24
+for n in $(seq 1 3); do
+    ovn-nbctl --wait=sb lsp-add sw6 "p5$n" -- lsp-set-addresses "p5$n" dynamic
+done
+AT_CHECK([ovn-nbctl get Logical-Switch-Port p51 dynamic_addresses], [0],
+    ["00:11:22:00:00:4d 192.168.100.2"
+])
+AT_CHECK([ovn-nbctl get Logical-Switch-Port p52 dynamic_addresses], [0],
+    ["00:11:22:00:00:4e 192.168.100.3"
+])
+AT_CHECK([ovn-nbctl get Logical-Switch-Port p53 dynamic_addresses], [0],
+    ["00:11:22:00:00:4f 192.168.100.4"
+])
+
 as ovn-sb
 OVS_APP_EXIT_AND_WAIT([ovsdb-server])
 
-- 
2.17.2



More information about the dev mailing list