From ef113c6f725349a2ab52f3cbef18403f82c84134 Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Tue, 6 Aug 2019 16:58:13 +0200
Subject: Filter: Allow to use sets in path masks

---
 filter/config.Y  |  4 ++++
 filter/test.conf |  1 +
 nest/a-path.c    | 31 ++++++++++++++++++++++++++++++-
 nest/attrs.h     |  4 +++-
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/filter/config.Y b/filter/config.Y
index 8171a7c2..a67a72a8 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -801,6 +801,10 @@ bgp_path:
 bgp_path_tail:
    NUM bgp_path_tail		{ $$ = f_new_inst(FI_CONSTANT, (struct f_val) { .type = T_PATH_MASK_ITEM, .val.pmi = { .asn = $1, .kind = PM_ASN, }, }); $$->next = $2;  }
  | NUM DDOT NUM bgp_path_tail	{ $$ = f_new_inst(FI_CONSTANT, (struct f_val) { .type = T_PATH_MASK_ITEM, .val.pmi = { .from = $1, .to = $3, .kind = PM_ASN_RANGE }, }); $$->next = $4; }
+ | '[' set_items ']' bgp_path_tail {
+   if ($2->from.type != T_INT) cf_error("Only integer sets allowed in path mask");
+   $$ = f_new_inst(FI_CONSTANT, (struct f_val) { .type = T_PATH_MASK_ITEM, .val.pmi = { .set = build_tree($2), .kind = PM_ASN_SET }, }); $$->next = $4;
+ }
  | '*' bgp_path_tail		{ $$ = f_new_inst(FI_CONSTANT, (struct f_val) { .type = T_PATH_MASK_ITEM, .val.pmi = { .kind = PM_ASTERISK }, }); $$->next = $2; }
  | '?' bgp_path_tail		{ $$ = f_new_inst(FI_CONSTANT, (struct f_val) { .type = T_PATH_MASK_ITEM, .val.pmi = { .kind = PM_QUESTION }, }); $$->next = $2; }
  | bgp_path_expr bgp_path_tail	{ $$ = $1; $$->next = $2; }
diff --git a/filter/test.conf b/filter/test.conf
index 9abd76f3..04074965 100644
--- a/filter/test.conf
+++ b/filter/test.conf
@@ -626,6 +626,7 @@ bgppath p2;
 	bt_assert(p2 !~ [8, ten..(2*ten)]);
 	bt_assert(p2 ~ [= * 4 3 * 1 =]);
 	bt_assert(p2 ~ [= (3+2) (2*2) 3 2 1 =]);
+	bt_assert(p2 ~ [= 5 [2, 4, 6] 3 [1..2] 1 =]);
 	bt_assert(p2 ~ mkpath(5, 4));
 
 	bt_assert(p2.len = 5);
diff --git a/nest/a-path.c b/nest/a-path.c
index a1b7c42f..4ee34cf4 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -740,6 +740,31 @@ pm_match(struct pm_pos *pos, u32 asn, u32 asn2)
   return 0;
 }
 
+static int
+pm_match_set(struct pm_pos *pos, struct f_tree *set)
+{
+  struct f_val asn = { .type = T_INT };
+
+  if (! pos->set)
+  {
+    asn.val.i = pos->val.asn;
+    return !!find_tree(set, &asn);
+  }
+
+  const u8 *p = pos->val.sp;
+  int len = *p++;
+  int i;
+
+  for (i = 0; i < len; i++)
+  {
+    asn.val.i = get_as(p + i * BS);
+    if (find_tree(set, &asn))
+      return 1;
+  }
+
+  return 0;
+}
+
 static void
 pm_mark(struct pm_pos *pos, int i, int plen, int *nl, int *nh)
 {
@@ -824,13 +849,17 @@ as_path_match(const struct adata *path, const struct f_path_mask *mask)
 	  val2 = mask->item[m].to;
 	  goto step;
 	case PM_QUESTION:
+	case PM_ASN_SET:
 	step:
 	  nh = nl = -1;
 	  for (i = h; i >= l; i--)
 	    if (pos[i].mark)
 	      {
 		pos[i].mark = 0;
-		if ((mask->item[m].kind == PM_QUESTION) || pm_match(pos + i, val, val2))
+		if ((mask->item[m].kind == PM_QUESTION) ||
+		    ((mask->item[m].kind != PM_ASN_SET) ?
+		     pm_match(pos + i, val, val2) :
+		     pm_match_set(pos + i, mask->item[m].set)))
 		  pm_mark(pos, i, plen, &nl, &nh);
 	      }
 
diff --git a/nest/attrs.h b/nest/attrs.h
index 4efcff79..a17b8c05 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -60,16 +60,18 @@ static inline struct adata *as_path_prepend(struct linpool *pool, const struct a
 #define PM_ASTERISK	2
 #define PM_ASN_EXPR	3
 #define PM_ASN_RANGE	4
+#define PM_ASN_SET	5
 
 struct f_path_mask_item {
   union {
     u32 asn; /* PM_ASN */
     struct f_line *expr; /* PM_ASN_EXPR */
+    struct f_tree *set; /* PM_ASN_SET */
     struct { /* PM_ASN_RANGE */
       u32 from;
       u32 to;
     };
-  }; 
+  };
   int kind;
 };
 
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