Review feedback

- Add const-assert that VNI search range is valid
- Rename `Vpc::with_random_vni()`

nexus/db-model/src/vpc.rs

@@ -115,7 +115,7 @@ impl IncompleteVpc {
     ///
     /// This is used to retry insertion of a VPC in the case where we can't find
     /// an available VNI.
-    pub fn with_new_vni(self) -> Self {
+    pub fn with_random_vni(self) -> Self {
         Self { vni: Vni(external::Vni::random()), ..self }
     }
 }

nexus/db-queries/Cargo.toml

@@ -47,6 +47,7 @@ serde_urlencoded.workspace = true
 serde_with.workspace = true
 sled-agent-client.workspace = true
 slog.workspace = true
+static_assertions.workspace = true
 steno.workspace = true
 thiserror.workspace = true
 tokio = { workspace = true, features = [ "full" ] }

nexus/db-queries/src/db/datastore/vpc.rs

@@ -313,7 +313,7 @@ impl DataStore {
                 Ok(Some(vpcs)) => return Ok(vpcs),
                 Err(e) => return Err(e),
                 Ok(None) => {
-                    vpc = vpc.with_new_vni();
+                    vpc = vpc.with_random_vni();
                     debug!(
                         opctx.log,
                         "VNI exhaustion detected while inserting VPC, retrying";

nexus/db-queries/src/db/queries/vpc.rs

@@ -294,6 +294,13 @@ pub const MAX_VNI_SEARCH_RANGE_SIZE: u32 = 2048;
 #[cfg(test)]
 pub const MAX_VNI_SEARCH_RANGE_SIZE: u32 = 10;
 
+// Ensure that we cannot search a range that extends beyond the valid guest VNI
+// range.
+static_assertions::const_assert!(
+    MAX_VNI_SEARCH_RANGE_SIZE
+        <= (external::Vni::MAX_VNI - external::Vni::MIN_GUEST_VNI)
+);
+
 impl VniShifts {
     fn new(vni: Vni) -> Self {
         let base_u32 = u32::from(vni.0);