staticd: Avoid requesting SRv6 sid from zebra when loc and sid block dont match

Currently, when the locator block and sid block differs, staticd would
still go ahead and request zebra to allocate the SID which it does if
there is atleast one match (from any locators).

Only when staticd tries to install the route, it sees that the locator
block and sid block are different and avoids installing the route.

Fix:
Check if the locator block and sid block match before even requesting
Zebra to allocate one.

Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/topotests/static_srv6_sids/test_static_srv6_sids.py b/tests/topotests/static_srv6_sids/test_static_srv6_sids.py
index 1ea94c8c07..abf49df046 100755
--- a/tests/topotests/static_srv6_sids/test_static_srv6_sids.py
+++ b/tests/topotests/static_srv6_sids/test_static_srv6_sids.py
@@ -210,6 +210,36 @@ def test_srv6_static_sids_sid_modify():
     check_srv6_static_sids(router, "expected_srv6_sids_sid_modify.json")
 
 
+def test_srv6_static_sids_wrong_sid_block():
+    """
+    The purpose of this test is to verify how FRR behaves when the user
+    provides an invalid configuration.
+    Add a new static Sid with a mismatch in locator and sid block
+    to make sure no Sid is allocated by zebra (TBD: Strict verify once show cmd
+    commit is merged (#16836))
+    """
+    router = get_topogen().gears["r1"]
+    router.vtysh_cmd(
+        """
+        configure terminal
+         segment-routing
+          srv6
+           locators
+            locator MAIN1
+             prefix fcbb:1234:1::/48 block-len 32 node-len 16 func-bits 16
+          srv6
+           static-sids
+            sid fcbb:bbbb:1:fe50::/64 locator MAIN1 behavior uA interface sr0 nexthop 2001::3
+        """
+    )
+
+    output = json.loads(router.vtysh_cmd("show ipv6 route static json"))
+    if "fcbb:bbbb:1:fe50::/64" in output:
+        assert (
+            False
+        ), "Failed. Expected no entry for fcbb:bbbb:1:fe50::/64 since loc and node block dont match"
+
+
 def test_srv6_static_sids_sid_delete_all():
     """
     Remove all static SIDs and verify they get removed