From df5a08e7c717ff421a52b4144d741f0a9749159f Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Tue, 31 Oct 2023 11:52:30 +0100
Subject: [PATCH] Filter: value hashing

Added a code for computing hash of filter values.

This is a split-commit of the neighboring aggregator branch
with improved lvalue and attribute handling.
---
 filter/data.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 filter/data.h |  3 +++
 2 files changed, 72 insertions(+)

diff --git a/filter/data.c b/filter/data.c
index de745654..5d36b0f5 100644
--- a/filter/data.c
+++ b/filter/data.c
@@ -586,6 +586,75 @@ val_in_range(const struct f_val *v1, const struct f_val *v2)
   return F_CMP_ERROR;
 }
 
+uint
+val_hash(struct f_val *v)
+{
+  u64 haux;
+  mem_hash_init(&haux);
+  mem_hash_mix_f_val(&haux, v);
+  return mem_hash_value(&haux);
+}
+
+void
+mem_hash_mix_f_val(u64 *h, struct f_val *v)
+{
+  mem_hash_mix_num(h, v->type);
+
+#define MX(k) mem_hash_mix(h, &IT(k), sizeof IT(k));
+#define IT(k) v->val.k
+
+  switch (v->type)
+  {
+    case T_VOID:
+      break;
+    case T_INT:
+    case T_BOOL:
+    case T_PAIR:
+    case T_QUAD:
+    case T_ENUM:
+      MX(i);
+      break;
+    case T_EC:
+    case T_RD:
+      MX(ec);
+      break;
+    case T_LC:
+      MX(lc);
+      break;
+    case T_IP:
+      MX(ip);
+      break;
+    case T_NET:
+      mem_hash_mix_num(h, net_hash(IT(net)));
+      break;
+    case T_STRING:
+      mem_hash_mix_str(h, IT(s));
+      break;
+    case T_PATH_MASK:
+      mem_hash_mix(h, IT(path_mask), sizeof(*IT(path_mask)) + IT(path_mask)->len * sizeof (IT(path_mask)->item));
+      break;
+    case T_PATH:
+    case T_CLIST:
+    case T_ECLIST:
+    case T_LCLIST:
+    case T_BYTESTRING:
+      mem_hash_mix(h, IT(ad)->data, IT(ad)->length);
+      break;
+    case T_SET:
+      MX(t);
+      break;
+    case T_PREFIX_SET:
+      MX(ti);
+      break;
+
+    case T_NONE:
+    case T_PATH_MASK_ITEM:
+    case T_ROUTE:
+    case T_ROUTES_BLOCK:
+      bug("Invalid type %s in f_val hashing", f_type_name(v->type));
+  }
+}
+
 /*
  * rte_format - format route information
  */
diff --git a/filter/data.h b/filter/data.h
index 103591b7..fbf21dcb 100644
--- a/filter/data.h
+++ b/filter/data.h
@@ -305,6 +305,9 @@ void val_format(const struct f_val *v, buffer *buf);
 char *val_format_str(struct linpool *lp, const struct f_val *v);
 const char *val_dump(const struct f_val *v);
 
+uint val_hash(struct f_val *);
+void mem_hash_mix_f_val(u64 *, struct f_val *);
+
 static inline int val_is_ip4(const struct f_val *v)
 { return (v->type == T_IP) && ipa_is_ip4(v->val.ip); }
 int val_in_range(const struct f_val *v1, const struct f_val *v2);