mempool: reinsert claims and airdrops after reorg

lib/mempool/mempool.js

@@ -405,10 +405,22 @@ class Mempool extends EventEmitter {
     const remove = [];
     const lockFlags = common.lockFlags.STANDARD_LOCKTIME_FLAGS;
 
-    this.dropClaims();
-    this.dropAirdrops();
     this.contracts.clear();
 
+    for (const entry of this.claims.values()) {
+      const claim = Claim.fromBlob(entry.blob);
+      const data = claim.getData(this.network);
+      // The only thing that might make a Claim invalid when rewinding the
+      // blockchain is the inception time of the signatures in the DNSSEC proof.
+      if (this.chain.tip.time < data.inception) {
+        // Claim is not still valid, remove from mempool and contract state.
+        this.untrackClaim(entry);
+      } else {
+        // Claim IS still valid, keep in mempool and re-add to contract state.
+        this.contracts.addName(entry.namehash);
+      }
+    }
+
     for (const [hash, entry] of this.map) {
       const {tx} = entry;