From a2a268da4f0c05012d691b57f9b358e3f35ef121 Mon Sep 17 00:00:00 2001
From: Alexander Zubkov <green@qrator.net>
Date: Tue, 28 Dec 2021 03:46:13 +0100
Subject: [PATCH] Filter: Add operators to pick community components

Add operators that can be used to pick components from
pair (standard community) or lc (large community) types.
For example:

(10, 20).asn --> 10
(10, 20).data --> 20

(10, 20, 30).asn --> 10
(10, 20, 30).data1 --> 20
(10, 20, 30).data2 --> 30

Signed-off-by: Alexander Zubkov <green@qrator.net>
---
 filter/config.Y  |  6 +++++-
 filter/f-inst.c  | 46 +++++++++++++++++++++++++++++++++++++++-------
 filter/test.conf |  9 +++++++++
 3 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/filter/config.Y b/filter/config.Y
index 7820e719..2fb55e4e 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -283,6 +283,7 @@ CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
 	ROA_CHECK, ASN, SRC, DST,
 	IS_V4, IS_V6,
 	LEN, MAXLEN,
+	DATA, DATA1, DATA2,
 	DEFINED,
 	ADD, DELETE, CONTAINS, RESET,
 	PREPEND, FIRST, LAST, LAST_NONAGGREGATED, MATCH,
@@ -789,13 +790,16 @@ term:
  | term '.' RD { $$ = f_new_inst(FI_ROUTE_DISTINGUISHER, $1); }
  | term '.' LEN { $$ = f_new_inst(FI_LENGTH, $1); }
  | term '.' MAXLEN { $$ = f_new_inst(FI_ROA_MAXLEN, $1); }
- | term '.' ASN { $$ = f_new_inst(FI_ROA_ASN, $1); }
+ | term '.' ASN { $$ = f_new_inst(FI_ASN, $1); }
  | term '.' SRC { $$ = f_new_inst(FI_NET_SRC, $1); }
  | term '.' DST { $$ = f_new_inst(FI_NET_DST, $1); }
  | term '.' MASK '(' term ')' { $$ = f_new_inst(FI_IP_MASK, $1, $5); }
  | term '.' FIRST { $$ = f_new_inst(FI_AS_PATH_FIRST, $1); }
  | term '.' LAST  { $$ = f_new_inst(FI_AS_PATH_LAST, $1); }
  | term '.' LAST_NONAGGREGATED  { $$ = f_new_inst(FI_AS_PATH_LAST_NAG, $1); }
+ | term '.' DATA { $$ = f_new_inst(FI_PAIR_DATA, $1); }
+ | term '.' DATA1 { $$ = f_new_inst(FI_LC_DATA1, $1); }
+ | term '.' DATA2 { $$ = f_new_inst(FI_LC_DATA2, $1); }
 
 /* Communities */
 /* This causes one shift/reduce conflict
diff --git a/filter/f-inst.c b/filter/f-inst.c
index b876a937..7e9e77d2 100644
--- a/filter/f-inst.c
+++ b/filter/f-inst.c
@@ -910,14 +910,31 @@
       ((net_addr_roa6 *) v1.val.net)->max_pxlen);
   }
 
-  INST(FI_ROA_ASN, 1, 1) { 	/* Get ROA ASN */
-    ARG(1, T_NET);
-    if (!net_is_roa(v1.val.net))
-      runtime( "ROA expected" );
+  INST(FI_ASN, 1, 1) { 	/* Get ROA ASN or community ASN part */
+    ARG_ANY(1);
+    RESULT_TYPE(T_INT);
+    switch(v1.type)
+    {
+      case T_NET:
+        if (!net_is_roa(v1.val.net))
+          runtime( "ROA expected" );
 
-    RESULT(T_INT, i, (v1.val.net->type == NET_ROA4) ?
-      ((net_addr_roa4 *) v1.val.net)->asn :
-      ((net_addr_roa6 *) v1.val.net)->asn);
+        RESULT_(T_INT, i, (v1.val.net->type == NET_ROA4) ?
+          ((net_addr_roa4 *) v1.val.net)->asn :
+          ((net_addr_roa6 *) v1.val.net)->asn);
+        break;
+
+      case T_PAIR:
+        RESULT_(T_INT, i, v1.val.i >> 16);
+        break;
+
+      case T_LC:
+        RESULT_(T_INT, i, v1.val.lc.asn);
+        break;
+
+      default:
+        runtime( "Net, pair or lc expected" );
+    }
   }
 
   INST(FI_IP, 1, 1) {	/* Convert prefix to ... */
@@ -951,6 +968,21 @@
     RESULT(T_INT, i, as_path_get_last_nonaggregated(v1.val.ad));
   }
 
+  INST(FI_PAIR_DATA, 1, 1) {	/* Get data part from the standard community */
+    ARG(1, T_PAIR);
+    RESULT(T_INT, i, v1.val.i & 0xFFFF);
+  }
+
+  INST(FI_LC_DATA1, 1, 1) {	/* Get data1 part from the large community */
+    ARG(1, T_LC);
+    RESULT(T_INT, i, v1.val.lc.ldp1);
+  }
+
+  INST(FI_LC_DATA2, 1, 1) {	/* Get data2 part from the large community */
+    ARG(1, T_LC);
+    RESULT(T_INT, i, v1.val.lc.ldp2);
+  }
+
   INST(FI_RETURN, 1, 1) {
     NEVER_CONSTANT;
     /* Acquire the return value */
diff --git a/filter/test.conf b/filter/test.conf
index 3a8804a1..6f2f6fb5 100644
--- a/filter/test.conf
+++ b/filter/test.conf
@@ -684,6 +684,11 @@ clist l;
 clist l2;
 clist r;
 {
+	bt_assert((10, 20).asn = 10);
+	bt_assert((10, 20).data = 20);
+	bt_assert(p23.asn = 2);
+	bt_assert(p23.data = 3);
+
 	l = - empty -;
 	bt_assert(l !~ [(*,*)]);
 	bt_assert((l ~ [(*,*)]) != (l !~ [(*,*)]));
@@ -940,6 +945,10 @@ lclist r;
 	bt_assert(---empty--- = ---empty---);
 	bt_assert((10, 20, 30) !~ ---empty---);
 
+	bt_assert((10, 20, 30).asn = 10);
+	bt_assert((10, 20, 30).data1 = 20);
+	bt_assert((10, 20, 30).data2 = 30);
+
 	ll = --- empty ---;
 	ll = add(ll, (ten, 20, 30));
 	ll = add(ll, (1000, 2000, 3000));