add mixability validation support

src/seraphis_main/tx_validation_context.h

@@ -95,6 +95,13 @@ class TxValidationContext
     */
     virtual void get_reference_set_proof_elements_v2(const std::vector<std::uint64_t> &indices,
         rct::keyV &proof_elements_out) const = 0;
+    /**
+     * @brief gets the total number of on-chain, non-Seraphis enotes for a given amount in the validation context
+     *
+     * @param amount the output enote amount to get information for, with 0 meaning the RingCT dist
+     * @return std::uint64_t the current total number of on-chain enotes for the given amount
+     */
+    virtual std::uint64_t get_cryptonote_global_ref_set_size(const std::uint64_t amount) const = 0;
 };
 
 } //namespace sp

src/seraphis_main/txtype_base.cpp

@@ -63,24 +63,32 @@ static bool validate_txs_impl(const std::vector<const SpTxType*> &txs, const TxV
             if (!validate_tx_version(*tx, tx_validation_context))
                 return false;
 
-            // Validate as many non-cryptographic static semantic rules against tx's nominal version as possible
+            // Validate as many non-cryptographic static semantic rules against tx's nominal version
+            // as possible
             if (!validate_tx_semantics(*tx))
                 return false;
 
-            // Validate non-cryptographic semantic rules for this tx which are dependent on the fork version (i.e. most
-            // Cryptonote/RingCT rules)
+            // Validate non-cryptographic semantic rules for this tx which are dependent on the fork
+            // version (i.e. most Cryptonote/RingCT rules)
             if (!validate_tx_semantics_fork_dependent(*tx, tx_validation_context))
                 return false;
 
-            // Validate that the key images do not exist in this validation context (and are otherwise valid)
+            // Validate that the key images do not exist in this validation context (and are
+            // otherwise valid)
             if (!validate_tx_key_images(*tx, tx_validation_context))
                 return false;
 
             // Validate amount balances: plaintext or confidential
             if (!validate_tx_amount_balance(*tx))
                 return false;
 
-            // Validate membership proofs, ring sigs, etc against live data (unless done in validate_txs_batchable)
+            // Validate that the transaction's ring sizes and signature types are allowed given the
+            // current size of the on-chain global output enote sets' sizes.
+            if (!validate_tx_mixability(*tx, tx_validation_context))
+                return false;
+
+            // Validate membership proofs, ring sigs, etc against live data (unless done in
+            // validate_txs_batchable())
             if (!validate_tx_input_proofs(*tx, tx_validation_context))
                 return false;
         }

src/seraphis_main/txtype_base.h

@@ -76,6 +76,8 @@ bool validate_tx_key_images(const SpTxType &tx, const TxValidationContext &tx_va
 template <typename SpTxType>
 bool validate_tx_amount_balance(const SpTxType &tx);
 template <typename SpTxType>
+bool validate_tx_mixability(const SpTxType &tx, const TxValidationContext &tx_validation_context);
+template <typename SpTxType>
 bool validate_tx_input_proofs(const SpTxType &tx, const TxValidationContext &tx_validation_context);
 template <typename SpTxType>
 bool validate_txs_batchable(const std::vector<const SpTxType*> &txs, const TxValidationContext &tx_validation_context);