[ovs-dev] [PATCH ovn 1/2] Add support to Default Router Preference (PRF) - RFC 4191

Lorenzo Bianconi lorenzo.bianconi at redhat.com
Thu Nov 14 11:38:48 UTC 2019


Introduce support for Default Router Preference (PRF) in IPv6 Router
Advertisement according to RFC 4191

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
---
 controller/pinctrl.c | 20 +++++++++++++++++---
 lib/ovn-l7.h         |  4 ++++
 northd/ovn-northd.c  |  7 +++++++
 ovn-nb.xml           | 12 ++++++++++++
 tests/ovn.at         | 13 +++++++++----
 5 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/controller/pinctrl.c b/controller/pinctrl.c
index a90ee73d6..b736b60ad 100644
--- a/controller/pinctrl.c
+++ b/controller/pinctrl.c
@@ -2263,10 +2263,10 @@ ipv6_ra_update_config(const struct sbrec_port_binding *pb)
         goto fail;
     }
     if (!strcmp(address_mode, "dhcpv6_stateless")) {
-        config->mo_flags = IPV6_ND_RA_FLAG_OTHER_ADDR_CONFIG;
+        config->mo_flags |= IPV6_ND_RA_FLAG_OTHER_ADDR_CONFIG;
         config->la_flags |= IPV6_ND_RA_OPT_PREFIX_AUTONOMOUS;
     } else if (!strcmp(address_mode, "dhcpv6_stateful")) {
-        config->mo_flags = IPV6_ND_RA_FLAG_MANAGED_ADDR_CONFIG;
+        config->mo_flags |= IPV6_ND_RA_FLAG_MANAGED_ADDR_CONFIG;
     } else if (!strcmp(address_mode, "slaac")) {
         config->la_flags |= IPV6_ND_RA_OPT_PREFIX_AUTONOMOUS;
     } else {
@@ -2274,6 +2274,13 @@ ipv6_ra_update_config(const struct sbrec_port_binding *pb)
         goto fail;
     }
 
+    const char *prf = smap_get(&pb->options, "ipv6_ra_prf");
+    if (!strcmp(prf, "HIGH")) {
+        config->mo_flags |= IPV6_ND_RA_OPT_PRF_HIGH;
+    } else if (!strcmp(prf, "LOW")) {
+        config->mo_flags |= IPV6_ND_RA_OPT_PRF_LOW;
+    }
+
     const char *prefixes = smap_get(&pb->options, "ipv6_ra_prefixes");
     if (prefixes && !extract_ip_addresses(prefixes, &config->prefixes)) {
         VLOG_WARN("Invalid IPv6 prefixes: %s", prefixes);
@@ -2423,10 +2430,17 @@ ipv6_ra_send(struct rconn *swconn, struct ipv6_ra_state *ra)
 
     uint64_t packet_stub[128 / 8];
     struct dp_packet packet;
+    uint16_t router_lt = IPV6_ND_RA_LIFETIME;
+
+    if (!router_lt) {
+        /* Reset PRF to MEDIUM if router lifetime is not set */
+        ra->config->mo_flags &= ~IPV6_ND_RA_OPT_PRF_LOW;
+    }
+
     dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub);
     compose_nd_ra(&packet, ra->config->eth_src, ra->config->eth_dst,
             &ra->config->ipv6_src, &ra->config->ipv6_dst,
-            255, ra->config->mo_flags, htons(IPV6_ND_RA_LIFETIME), 0, 0,
+            255, ra->config->mo_flags, htons(router_lt), 0, 0,
             ra->config->mtu);
 
     for (int i = 0; i < ra->config->prefixes.n_ipv6_addrs; i++) {
diff --git a/lib/ovn-l7.h b/lib/ovn-l7.h
index 5fc370bf5..fd898b0dc 100644
--- a/lib/ovn-l7.h
+++ b/lib/ovn-l7.h
@@ -287,6 +287,10 @@ nd_ra_opts_destroy(struct hmap *nd_ra_opts)
 #define IPV6_ND_RA_OPT_PREFIX_VALID_LIFETIME        0xffffffff
 #define IPV6_ND_RA_OPT_PREFIX_PREFERRED_LIFETIME    0xffffffff
 
+#define IPV6_ND_RA_OPT_PRF_NORMAL                   0x00
+#define IPV6_ND_RA_OPT_PRF_HIGH                     0x08
+#define IPV6_ND_RA_OPT_PRF_LOW                      0x18
+
 static inline void
 nd_ra_opts_init(struct hmap *nd_ra_opts)
 {
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index d6beb9768..a1eaa9071 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -6757,6 +6757,13 @@ copy_ra_to_sb(struct ovn_port *op, const char *address_mode)
 
     smap_add(&options, "ipv6_ra_src_eth", op->lrp_networks.ea_s);
 
+    const char *prf = smap_get(&op->nbrp->ipv6_ra_configs, "prf");
+    if (!prf || (strcmp(prf, "HIGH") && strcmp(prf, "LOW"))) {
+        smap_add(&options, "ipv6_ra_prf", "MEDIUM");
+    } else {
+        smap_add(&options, "ipv6_ra_prf", prf);
+    }
+
     sbrec_port_binding_set_options(op->sb, &options);
     smap_destroy(&options);
 }
diff --git a/ovn-nb.xml b/ovn-nb.xml
index d8f3237fc..89d23ad7b 100644
--- a/ovn-nb.xml
+++ b/ovn-nb.xml
@@ -1859,6 +1859,18 @@
         </ul>
       </column>
 
+      <column name="ipv6_ra_configs" key="prf">
+        Default Router Preference (PRF) indicates whether to prefer this
+        router over other default routers (RFC 4191).
+        Possible values are:
+
+        <ul>
+          <li>HIGH: mapped to 0x01 in RA PRF field</li>
+          <li>MEDIUM: mapped to 0x00 in RA PRF field</li>
+          <li>LOW: mapped to 0x11 in RA PRF field</li>
+        </ul>
+      </column>
+
       <column name="ipv6_ra_configs" key="mtu">
         The recommended MTU for the link. Default is 0, which means no MTU
         Option will be included in RA packet replied by ovn-controller.
diff --git a/tests/ovn.at b/tests/ovn.at
index 4a10a11e9..85d539c78 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -11504,23 +11504,28 @@ ra_test 000005dc 00 0 0 c0 40 aef00000000000000000000000000000
 ovn-nbctl --wait=hv set Logical_Router_port ro-sw networks='aef0\:\:1/64 fd0f\:\:1/48'
 ra_test 000005dc 00 0 0 c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
 
+# Test PRF for default gw
+ovn-nbctl --wait=hv set Logical_Router_port ro-sw ipv6_ra_configs:prf="LOW"
+ra_test 000005dc 18 0 0 c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
+
 # Now test for RDNSS
 ovn-nbctl --wait=hv set Logical_Router_port ro-sw ipv6_ra_configs:rdnss='aef0::11'
 dns_addr=aef00000000000000000000000000011
-ra_test 000005dc 00 $dns_addr 0 c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
+ra_test 000005dc 18 $dns_addr 0 c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
 
 # Now test for DNSSL
 ovn-nbctl --wait=hv set Logical_Router_port ro-sw ipv6_ra_configs:dnssl="aa.bb.cc"
+ovn-nbctl --wait=hv set Logical_Router_port ro-sw ipv6_ra_configs:prf="HIGH"
 dnssl=02616102626202636300000000000000
-ra_test 000005dc 00 $dns_addr $dnssl c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
+ra_test 000005dc 08 $dns_addr $dnssl c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
 
 ## Test a different address mode now
 ovn-nbctl --wait=hv set Logical_Router_Port ro-sw ipv6_ra_configs:address_mode=dhcpv6_stateful
-ra_test 000005dc 80 $dns_addr $dnssl 80 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
+ra_test 000005dc 88 $dns_addr $dnssl 80 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
 
 # And the other address mode
 ovn-nbctl --wait=hv set Logical_Router_Port ro-sw ipv6_ra_configs:address_mode=dhcpv6_stateless
-ra_test 000005dc 40 $dns_addr $dnssl c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
+ra_test 000005dc 48 $dns_addr $dnssl c0 40 aef00000000000000000000000000000 30 fd0f0000000000000000000000000000
 
 OVN_CLEANUP([hv1],[hv2])
 AT_CLEANUP
-- 
2.21.0



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