From cc31b75a8fd7949533c12db2c3e9d67eeaf46d10 Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Tue, 9 Jul 2013 23:27:10 +0200
Subject: Implements 'bgppath ~ int set' filter op.

---
 nest/attrs.h | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'nest/attrs.h')

diff --git a/nest/attrs.h b/nest/attrs.h
index 42f81a10..12f2fcf4 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -25,6 +25,8 @@
  * to 16bit slot (like in 16bit AS_PATH). See RFC 4893 for details
  */
 
+struct f_tree;
+
 struct adata *as_path_prepend(struct linpool *pool, struct adata *olda, u32 as);
 int as_path_convert_to_old(struct adata *path, byte *dst, int *new_used);
 int as_path_convert_to_new(struct adata *path, byte *dst, int req_as);
@@ -34,6 +36,7 @@ int as_path_getlen_int(struct adata *path, int bs);
 int as_path_get_first(struct adata *path, u32 *orig_as);
 int as_path_get_last(struct adata *path, u32 *last_as);
 int as_path_is_member(struct adata *path, u32 as);
+int as_path_match_set(struct adata *path, struct f_tree *set);
 
 #define PM_ASN		0
 #define PM_QUESTION	1
-- 
cgit v1.2.3


From bff9ce5130d16af2fd802d42bdb2bff00980c9ae Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Thu, 15 Aug 2013 01:06:47 +0200
Subject: Extends delete/filter operators to work no bgp_paths.

---
 doc/bird.sgml    | 17 +++++++++++++--
 filter/filter.c  | 29 +++++++++++++++++++++++++-
 filter/test.conf |  4 ++++
 nest/a-path.c    | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 nest/attrs.h     |  2 ++
 5 files changed, 112 insertions(+), 3 deletions(-)

(limited to 'nest/attrs.h')

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 7db9fad2..3cd80c32 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -1033,10 +1033,23 @@ incompatible with each other (that is to prevent you from shooting in the foot).
 
           <cf><m/P/.len</cf> returns the length of path <m/P/.
 
-          <cf>prepend(<m/P/,<m/A/)</cf> prepends ASN <m/A/ to path <m/P/ and returns the result.
+          <cf>prepend(<m/P/,<m/A/)</cf> prepends ASN <m/A/ to path
+          <m/P/ and returns the result.
+
+          <cf>delete(<m/P/,<m/A/)</cf> deletes all instances of ASN
+	  <m/A/ from from path <m/P/ and returns the result.
+	  <m/A/ may also be an integer set, in that case the
+	  operator deletes all ASNs from path <m/P/ that are also
+	  members of set <m/A/.
+
+          <cf>filter(<m/P/,<m/A/)</cf> deletes all ASNs from path
+	  <m/P/ that are not members of integer set <m/A/.
+	  I.e., <cf/filter/ do the same as <cf/delete/ with inverted
+	  set <m/A/.
+
           Statement <cf><m/P/ = prepend(<m/P/, <m/A/);</cf> can be shortened to
           <cf><m/P/.prepend(<m/A/);</cf> if <m/P/ is appropriate route attribute
-          (for example <cf/bgp_path/).
+          (for example <cf/bgp_path/). Similarly for <cf/delete/ and <cf/filter/.
 
 	<tag/bgpmask/
 	  BGP masks are patterns used for BGP path matching
diff --git a/filter/filter.c b/filter/filter.c
index 98bae331..25587e0f 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -1165,7 +1165,34 @@ interpret(struct f_inst *what)
 
   case P('C','a'):	/* (Extended) Community list add or delete */
     TWOARGS;
-    if (v1.type == T_CLIST)
+    if (v1.type == T_PATH)
+    {
+      struct f_tree *set = NULL;
+      u32 key = 0;
+      int pos;
+
+      if (v2.type == T_INT)
+	key = v2.val.i;
+      else if ((v2.type == T_SET) && (v2.val.t->from.type == T_INT))
+	set = v2.val.t;
+      else
+	runtime("Can't delete non-integer (set)");
+
+      switch (what->aux)
+      {
+      case 'a':	runtime("Can't add to path");
+      case 'd':	pos = 0; break;
+      case 'f':	pos = 1; break;
+      default:	bug("unknown Ca operation");
+      }
+
+      if (pos && !set)
+	runtime("Can't filter integer");
+
+      res.type = T_PATH;
+      res.val.ad = as_path_filter(f_pool, v1.val.ad, set, key, pos);
+    }
+    else if (v1.type == T_CLIST)
     {
       /* Community (or cluster) list */
       struct f_val dummy;
diff --git a/filter/test.conf b/filter/test.conf
index 4f40abff..048983b5 100644
--- a/filter/test.conf
+++ b/filter/test.conf
@@ -104,6 +104,8 @@ eclist el2;
 	print "Should be true: ", p2 ~ [= (3+2) (2*2) 3 2 1 =], " ", p2 ~ mkpath(5, 4);
 	print "Should be true: ", p2.len = 5, " ", p2.first = 5, " ", p2.last = 1;
 	print "5 = ", p2.len;
+	print "Delete 3:   ", delete(p2, 3);
+	print "Filter 1-3: ", filter(p2, [1..3]);
 	
 	pm1 = [= 1 2 * 3 4 5 =];
 	p2 = prepend( + empty +, 5 );
@@ -113,6 +115,8 @@ eclist el2;
 	p2 = prepend( p2, 2 );
 	p2 = prepend( p2, 1 );
 	print "Should be true: ", p2 ~ pm1, " ", p2, " ", pm1;
+	print "Delete 3:   ", delete(p2, 3);
+	print "Delete 4-5: ", delete(p2, [4..5]);
 
 	l = - empty -;
 	print "Should be false in this special case: ", l ~ [(*,*)];
diff --git a/nest/a-path.c b/nest/a-path.c
index 712e77a3..b1812981 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -287,6 +287,69 @@ as_path_match_set(struct adata *path, struct f_tree *set)
   return 0;
 }
 
+struct adata *
+as_path_filter(struct linpool *pool, struct adata *path, struct f_tree *set, u32 key, int pos)
+{
+  if (!path)
+    return NULL;
+
+  int len = path->length;
+  u8 *p = path->data;
+  u8 *q = path->data + len;
+  u8 *d, *d2;
+  int i, bt, sn, dn;
+  u8 buf[len];
+
+  d = buf;
+  while (p<q)
+    {
+      /* Read block header (type and length) */
+      bt = p[0];
+      sn = p[1];
+      dn = 0;
+      p += 2;
+      d2 = d + 2;
+
+      for (i = 0; i < sn; i++)
+	{
+	  u32 as = get_as(p);
+	  int match;
+
+	  if (set)
+	    match = !!find_tree(set, (struct f_val){T_INT, .val.i = as});
+	  else
+	    match = (as == key);
+
+	  if (match == pos)
+	    {
+	      put_as(d2, as);
+	      d2 += BS;
+	      dn++;
+	    }
+
+	  p += BS;
+	}
+
+      if (dn > 0)
+	{
+	  /* Nonempty block, set block header and advance */
+	  d[0] = bt;
+	  d[1] = dn;
+	  d = d2;
+	}
+  }
+
+  int nl = d - buf;
+  if (nl == path->length)
+    return path;
+
+  struct adata *res = lp_alloc(pool, sizeof(struct adata) + nl);
+  res->length = nl;
+  memcpy(res->data, buf, nl);
+
+  return res;
+}
+
 
 struct pm_pos
 {
diff --git a/nest/attrs.h b/nest/attrs.h
index 12f2fcf4..44a23e18 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -37,6 +37,8 @@ int as_path_get_first(struct adata *path, u32 *orig_as);
 int as_path_get_last(struct adata *path, u32 *last_as);
 int as_path_is_member(struct adata *path, u32 as);
 int as_path_match_set(struct adata *path, struct f_tree *set);
+struct adata *as_path_filter(struct linpool *pool, struct adata *path, struct f_tree *set, u32 key, int pos);
+
 
 #define PM_ASN		0
 #define PM_QUESTION	1
-- 
cgit v1.2.3


From 7ccb36d3308ef57d340e663f0cabd24663f4f62a Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Wed, 2 Oct 2013 14:57:29 +0200
Subject: Implements C.len operator for clist and eclist types.

Thanks to Sergey Popovich for the original patch.
---
 doc/bird.sgml    | 2 ++
 filter/filter.c  | 4 +++-
 filter/test.conf | 5 +++--
 nest/attrs.h     | 3 +++
 4 files changed, 11 insertions(+), 3 deletions(-)

(limited to 'nest/attrs.h')

diff --git a/doc/bird.sgml b/doc/bird.sgml
index f43eb4bf..050acf33 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -1077,6 +1077,8 @@ incompatible with each other (that is to prevent you from shooting in the foot).
 	  no literals of this type. There are three special operators on
 	  clists:
 
+	  <cf><m/C/.len</cf> returns the length of clist <m/C/.
+
           <cf>add(<m/C/,<m/P/)</cf> adds pair (or quad) <m/P/ to clist
 	  <m/C/ and returns the result.  If item <m/P/ is already in
 	  clist <m/C/, it does nothing. <m/P/ may also be a clist,
diff --git a/filter/filter.c b/filter/filter.c
index 50e3f403..b01933f7 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -1067,7 +1067,9 @@ interpret(struct f_inst *what)
     switch(v1.type) {
     case T_PREFIX: res.val.i = v1.val.px.len; break;
     case T_PATH:   res.val.i = as_path_getlen(v1.val.ad); break;
-    default: runtime( "Prefix or path expected" );
+    case T_CLIST:  res.val.i = int_set_get_size(v1.val.ad); break;
+    case T_ECLIST: res.val.i = ec_set_get_size(v1.val.ad); break;
+    default: runtime( "Prefix, path, clist or eclist expected" );
     }
     break;
   case P('c','p'):	/* Convert prefix to ... */
diff --git a/filter/test.conf b/filter/test.conf
index b8f706cb..03b09c30 100644
--- a/filter/test.conf
+++ b/filter/test.conf
@@ -142,10 +142,10 @@ eclist el2;
 	l = add( l, (3,5) );
 	l2 = filter( l, [(3,*)] );
 	l = delete( l, [(3,2..4)] );
-	print "Community list (1,2) (3,1) (3,5) ", l;
+	print "Community list (1,2) (3,1) (3,5) ", l, " len: ", l.len;
 	l = add( l, (3,2) );
 	l = add( l, (4,5) );
-	print "Community list (1,2) (3,1) (3,2) (3,5) (4,5) ", l;
+	print "Community list (1,2) (3,1) (3,2) (3,5) (4,5) ", l, " len: ", l.len;
 	print "Should be true: ", l ~ [(*,2)], " ", l ~ [(*,5)], " ", l ~ [(*, one)];
 	print "Should be false: ", l ~ [(*,3)], " ", l ~ [(*,(one+6))], " ", l ~ [(*, (one+one+one))];
 	l = delete( l, [(*,(one+onef(3)))] );
@@ -168,6 +168,7 @@ eclist el2;
 	el = add(el, (ro, 11.21.31.41.mask(16), 200));
 	print "EC list (rt, 10, 20) (ro, 10.20.30.40, 100) (ro, 11.21.0.0, 200):";
 	print el;
+	print "EC len: ", el.len;
 	el = delete(el, (rt, 10, 20));
 	el = delete(el, (rt, 10, 30));
 	el = add(el, (unknown 2, ten, 1));
diff --git a/nest/attrs.h b/nest/attrs.h
index 44a23e18..a0dae221 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -69,6 +69,9 @@ int as_path_match(struct adata *path, struct f_path_mask *mask);
 static inline int int_set_get_size(struct adata *list)
 { return list->length / 4; }
 
+static inline int ec_set_get_size(struct adata *list)
+{ return list->length / 8; }
+
 static inline u32 *int_set_get_data(struct adata *list)
 { return (u32 *) list->data; }
 
-- 
cgit v1.2.3


From a15dab76f93337b07b4b03a64ac3bac26285dfd9 Mon Sep 17 00:00:00 2001
From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Mon, 21 Oct 2013 14:58:32 +0200
Subject: Implements 'allow local as' option.

Similar to allowas-in option on other routers.
---
 doc/bird.sgml      | 10 ++++++++++
 filter/filter.c    |  2 +-
 nest/a-path.c      |  6 ++++--
 nest/attrs.h       |  2 +-
 proto/bgp/attrs.c  |  3 ++-
 proto/bgp/bgp.h    |  1 +
 proto/bgp/config.Y |  4 +++-
 7 files changed, 22 insertions(+), 6 deletions(-)

(limited to 'nest/attrs.h')

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 2b9ffa02..63890031 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -1486,6 +1486,16 @@ for each neighbor using the following configuration parameters:
 	This option requires that the connected routing table is
 	<ref id="dsc-sorted" name="sorted">. Default: off.
 
+	<tag>allow local as [<m/number/]</tag> 
+	BGP prevents routing loops by rejecting received routes with
+	the local AS number in the AS path. This option allows to
+	loose or disable the check. Optional <cf/number/ argument can
+	be used to specify the maximum number of local ASNs in the AS
+	path that is allowed for received routes. When the option is
+	used without the argument, the check is completely disabled
+	and you should ensure loop-free behavior by some other means.
+	Default: 0 (no local AS number allowed).
+
 	<tag>enable route refresh <m/switch/</tag> When BGP speaker
 	changes its import filter, it has to re-examine all routes
 	received from its neighbor against the new filter. As these
diff --git a/filter/filter.c b/filter/filter.c
index b01933f7..a28de5df 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -392,7 +392,7 @@ val_in_range(struct f_val v1, struct f_val v2)
     return as_path_match(v1.val.ad, v2.val.path_mask);
 
   if ((v1.type == T_INT) && (v2.type == T_PATH))
-    return as_path_is_member(v2.val.ad, v1.val.i);
+    return as_path_contains(v2.val.ad, v1.val.i, 1);
 
   if (((v1.type == T_PAIR) || (v1.type == T_QUAD)) && (v2.type == T_CLIST))
     return int_set_contains(v2.val.ad, v1.val.i);
diff --git a/nest/a-path.c b/nest/a-path.c
index b1812981..dc36e653 100644
--- a/nest/a-path.c
+++ b/nest/a-path.c
@@ -244,10 +244,11 @@ as_path_get_first(struct adata *path, u32 *last_as)
 }
 
 int
-as_path_is_member(struct adata *path, u32 as)
+as_path_contains(struct adata *path, u32 as, int min)
 {
   u8 *p = path->data;
   u8 *q = p+path->length;
+  int num = 0;
   int i, n;
 
   while (p<q)
@@ -257,7 +258,8 @@ as_path_is_member(struct adata *path, u32 as)
       for(i=0; i<n; i++)
 	{
 	  if (get_as(p) == as)
-	    return 1;
+	    if (++num == min)
+	      return 1;
 	  p += BS;
 	}
     }
diff --git a/nest/attrs.h b/nest/attrs.h
index a0dae221..b6e067cb 100644
--- a/nest/attrs.h
+++ b/nest/attrs.h
@@ -35,7 +35,7 @@ int as_path_getlen(struct adata *path);
 int as_path_getlen_int(struct adata *path, int bs);
 int as_path_get_first(struct adata *path, u32 *orig_as);
 int as_path_get_last(struct adata *path, u32 *last_as);
-int as_path_is_member(struct adata *path, u32 as);
+int as_path_contains(struct adata *path, u32 as, int min);
 int as_path_match_set(struct adata *path, struct f_tree *set);
 struct adata *as_path_filter(struct linpool *pool, struct adata *path, struct f_tree *set, u32 key, int pos);
 
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index c27a4988..8e25c4d2 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -950,8 +950,9 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
 static inline int
 bgp_as_path_loopy(struct bgp_proto *p, rta *a)
 {
+  int num = p->cf->allow_local_as + 1;
   eattr *e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS_PATH));
-  return (e && as_path_is_member(e->u.ptr, p->local_as));
+  return (e && (num > 0) && as_path_contains(e->u.ptr, p->local_as, num));
 }
 
 static inline int
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 77a36715..bcbdf2cc 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -44,6 +44,7 @@ struct bgp_config {
   int passive;				/* Do not initiate outgoing connection */
   int interpret_communities;		/* Hardwired handling of well-known communities */
   int secondary;			/* Accept also non-best routes (i.e. RA_ACCEPTED) */
+  int allow_local_as;			/* Allow that number of local ASNs in incoming AS_PATHs */
   unsigned connect_retry_time;
   unsigned hold_time, initial_hold_time;
   unsigned keepalive_time;
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index d5e5aaca..f4b2c5fe 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -26,7 +26,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY,
 	PREFER, OLDER, MISSING, LLADDR, DROP, IGNORE, ROUTE, REFRESH,
 	INTERPRET, COMMUNITIES, BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP,
 	TABLE, GATEWAY, DIRECT, RECURSIVE, MED, TTL, SECURITY, DETERMINISTIC,
-	SECONDARY)
+	SECONDARY, ALLOW)
 
 CF_GRAMMAR
 
@@ -108,6 +108,8 @@ bgp_proto:
  | bgp_proto PASSIVE bool ';' { BGP_CFG->passive = $3; }
  | bgp_proto INTERPRET COMMUNITIES bool ';' { BGP_CFG->interpret_communities = $4; }
  | bgp_proto SECONDARY bool ';' { BGP_CFG->secondary = $3; }
+ | bgp_proto ALLOW LOCAL AS ';' { BGP_CFG->allow_local_as = -1; }
+ | bgp_proto ALLOW LOCAL AS expr ';' { BGP_CFG->allow_local_as = $5; }
  | bgp_proto IGP TABLE rtable ';' { BGP_CFG->igp_table = $4; }
  | bgp_proto TTL SECURITY bool ';' { BGP_CFG->ttl_security = $4; }
  ;
-- 
cgit v1.2.3