bgpd: aspath list format binds on as-notation format

Each BGP prefix may have an as-path list attached. A forged
string is stored in the BGP attribute and shows the as-path
list output.

Before this commit, the as-path list output was expressed as
a list of AS values in plain format. Now, if a given BGP instance
uses a specific asnotation, then the output is changed:

new output:
router bgp 1.1 asnotation dot
!
 address-family ipv4 unicast
  network 10.200.0.0/24 route-map rmap
  network 10.201.0.0/24 route-map rmap
  redistribute connected route-map rmap
 exit-address-family
exit
!
route-map rmap permit 1
 set as-path prepend 1.1 5433.55 264564564
exit

ubuntu2004# do show bgp ipv4
BGP table version is 2, local router ID is 10.0.2.15, vrf id 0
Default local pref 100, local AS 1.1
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

    Network          Next Hop            Metric LocPrf Weight Path
 *> 4.4.4.4/32       0.0.0.0                  0         32768 1.1 5433.55 4036.61268 ?
 *> 10.0.2.0/24      0.0.0.0                  0         32768 1.1 5433.55 4036.61268 ?
    10.200.0.0/24    0.0.0.0                  0         32768 1.1 5433.55 4036.61268 i
    10.201.0.0/24    0.0.0.0                  0         32768 1.1 5433.55 4036.61268 i

The changes include:
- the aspath structure has a new field: asnotation type
The ashash list will differentiate 2 aspaths using a different
asnotation.
- 3 new printf extensions display the as number in the wished
format: pASP, pASD, pASE for plain, dot, or dot+ format (extended).

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

bgpd/bgp_aspath.c

@@ -302,9 +302,13 @@ static struct assegment *assegment_normalise(struct assegment *head)
 	return head;
 }
 
-static struct aspath *aspath_new(void)
+static struct aspath *aspath_new(enum asnotation_mode asnotation)
 {
-	return XCALLOC(MTYPE_AS_PATH, sizeof(struct aspath));
+	struct aspath *as;
+
+	as = XCALLOC(MTYPE_AS_PATH, sizeof(struct aspath));
+	as->asnotation = asnotation;
+	return as;
 }
 
 /* Free AS path structure. */
@@ -552,8 +556,10 @@ static void aspath_make_str_count(struct aspath *as, bool make_json)
  *
  * This was changed to 10 after the well-known BGP assertion, which
  * had hit some parts of the Internet in May of 2009.
+ * plain format : '4294967295 ' : 10 + 1
+ * astod format : '65535.65535 ': 11 + 1
  */
-#define ASN_STR_LEN (10 + 1)
+#define ASN_STR_LEN (11 + 1)
 	str_size = MAX(assegment_count_asns(seg, 0) * ASN_STR_LEN + 2 + 1,
 		       ASPATH_STR_DEFAULT_LEN);
 	str_buf = XMALLOC(MTYPE_AS_STR, str_size);
@@ -584,7 +590,7 @@ static void aspath_make_str_count(struct aspath *as, bool make_json)
 
 /* We might need to increase str_buf, particularly if path has
  * differing segments types, our initial guesstimate above will
- * have been wrong. Need 10 chars for ASN, a separator each and
+ * have been wrong. Need 11 chars for ASN, a separator each and
  * potentially two segment delimiters, plus a space between each
  * segment and trailing zero.
  *
@@ -610,12 +616,11 @@ static void aspath_make_str_count(struct aspath *as, bool make_json)
 		/* write out the ASNs, with their separators, bar the last one*/
 		for (i = 0; i < seg->length; i++) {
 			if (make_json)
-				json_object_array_add(
+				asn_asn2json_array(jseg_list, seg->as[i],
-					jseg_list,
+						   as->asnotation);
-					json_object_new_int64(seg->as[i]));
+			len += snprintfrr(str_buf + len, str_size - len,
-
+					  ASN_FORMAT(as->asnotation),
-			len += snprintf(str_buf + len, str_size - len, "%u",
+					  &seg->as[i]);
-					seg->as[i]);
 
 			if (i < (seg->length - 1))
 				len += snprintf(str_buf + len, str_size - len,
@@ -706,6 +711,7 @@ struct aspath *aspath_dup(struct aspath *aspath)
 
 	new->str = XMALLOC(MTYPE_AS_STR, buflen);
 	new->str_len = aspath->str_len;
+	new->asnotation = aspath->asnotation;
 
 	/* copy the string data */
 	if (aspath->str_len > 0)
@@ -733,6 +739,7 @@ static void *aspath_hash_alloc(void *arg)
 	new->str = aspath->str;
 	new->str_len = aspath->str_len;
 	new->json = aspath->json;
+	new->asnotation = aspath->asnotation;
 
 	return new;
 }
@@ -840,7 +847,8 @@ static int assegments_parse(struct stream *s, size_t length,
 
    On error NULL is returned.
  */
-struct aspath *aspath_parse(struct stream *s, size_t length, int use32bit)
+struct aspath *aspath_parse(struct stream *s, size_t length, int use32bit,
+			    enum asnotation_mode asnotation)
 {
 	struct aspath as;
 	struct aspath *find;
@@ -855,6 +863,7 @@ struct aspath *aspath_parse(struct stream *s, size_t length, int use32bit)
 		return NULL;
 
 	memset(&as, 0, sizeof(as));
+	as.asnotation = asnotation;
 	if (assegments_parse(s, length, &as.segments, use32bit) < 0)
 		return NULL;
 
@@ -1072,7 +1081,7 @@ struct aspath *aspath_aggregate(struct aspath *as1, struct aspath *as2)
 			seg = assegment_append_asns(seg, seg1->as, match);
 
 			if (!aspath) {
-				aspath = aspath_new();
+				aspath = aspath_new(as1->asnotation);
 				aspath->segments = seg;
 			} else
 				prevseg->next = seg;
@@ -1092,7 +1101,7 @@ struct aspath *aspath_aggregate(struct aspath *as1, struct aspath *as2)
 	}
 
 	if (!aspath)
-		aspath = aspath_new();
+		aspath = aspath_new(as1->asnotation);
 
 	/* Make as-set using rest of all information. */
 	from = match;
@@ -1536,7 +1545,7 @@ struct aspath *aspath_filter_exclude(struct aspath *source,
 	struct assegment *srcseg, *exclseg, *lastseg;
 	struct aspath *newpath;
 
-	newpath = aspath_new();
+	newpath = aspath_new(source->asnotation);
 	lastseg = NULL;
 
 	for (srcseg = source->segments; srcseg; srcseg = srcseg->next) {
@@ -1766,7 +1775,7 @@ struct aspath *aspath_reconcile_as4(struct aspath *aspath,
 		newseg = assegment_append_asns(newseg, seg->as, cpasns);
 
 		if (!newpath) {
-			newpath = aspath_new();
+			newpath = aspath_new(aspath->asnotation);
 			newpath->segments = newseg;
 		} else
 			prevseg->next = newseg;
@@ -1895,16 +1904,16 @@ static void aspath_segment_add(struct aspath *as, int type)
 		as->segments = new;
 }
 
-struct aspath *aspath_empty(void)
+struct aspath *aspath_empty(enum asnotation_mode asnotation)
 {
-	return aspath_parse(NULL, 0, 1); /* 32Bit ;-) */
+	return aspath_parse(NULL, 0, 1, asnotation); /* 32Bit ;-) */
 }
 
 struct aspath *aspath_empty_get(void)
 {
 	struct aspath *aspath;
 
-	aspath = aspath_new();
+	aspath = aspath_new(bgp_get_asnotation(NULL));
 	aspath_make_str_count(aspath, false);
 	return aspath;
 }
@@ -1988,7 +1997,8 @@ static const char *aspath_gettoken(const char *buf, enum as_token *token,
 	return p;
 }
 
-struct aspath *aspath_str2aspath(const char *str)
+struct aspath *aspath_str2aspath(const char *str,
+				 enum asnotation_mode asnotation)
 {
 	enum as_token token = as_token_unknown;
 	unsigned short as_type;
@@ -1996,7 +2006,7 @@ struct aspath *aspath_str2aspath(const char *str)
 	struct aspath *aspath;
 	int needtype;
 
-	aspath = aspath_new();
+	aspath = aspath_new(asnotation);
 
 	/* We start default type as AS_SEQUENCE. */
 	as_type = AS_SEQUENCE;
@@ -2070,6 +2080,10 @@ bool aspath_cmp(const void *arg1, const void *arg2)
 	const struct assegment *seg1 = ((const struct aspath *)arg1)->segments;
 	const struct assegment *seg2 = ((const struct aspath *)arg2)->segments;
 
+	if (((const struct aspath *)arg1)->asnotation !=
+	    ((const struct aspath *)arg2)->asnotation)
+		return false;
+
 	while (seg1 || seg2) {
 		int i;
 		if ((!seg1 && seg2) || (seg1 && !seg2))

bgpd/bgp_aspath.h

@@ -72,6 +72,9 @@ struct aspath {
 	   and AS path regular expression match.  */
 	char *str;
 	unsigned short str_len;
+
+	/* AS notation used by string expression of AS path */
+	enum asnotation_mode asnotation;
 };
 
 #define ASPATH_STR_DEFAULT_LEN 32
@@ -80,7 +83,9 @@ struct aspath {
 extern void aspath_init(void);
 extern void aspath_finish(void);
 extern struct aspath *aspath_parse(struct stream *s, size_t length,
-				   int use32bit);
+				   int use32bit,
+				   enum asnotation_mode asnotation);
+
 extern struct aspath *aspath_dup(struct aspath *aspath);
 extern struct aspath *aspath_aggregate(struct aspath *as1, struct aspath *as2);
 extern struct aspath *aspath_prepend(struct aspath *as1, struct aspath *as2);
@@ -96,9 +101,10 @@ extern bool aspath_cmp_left(const struct aspath *aspath1,
 extern bool aspath_cmp_left_confed(const struct aspath *as1,
 				   const struct aspath *as2);
 extern struct aspath *aspath_delete_confed_seq(struct aspath *aspath);
-extern struct aspath *aspath_empty(void);
+extern struct aspath *aspath_empty(enum asnotation_mode asnotation);
 extern struct aspath *aspath_empty_get(void);
-extern struct aspath *aspath_str2aspath(const char *str);
+extern struct aspath *aspath_str2aspath(const char *str,
+					enum asnotation_mode asnotation);
 extern void aspath_str_update(struct aspath *as, bool make_json);
 extern void aspath_free(struct aspath *aspath);
 extern struct aspath *aspath_intern(struct aspath *aspath);

bgpd/bgp_attr.c

@@ -1069,7 +1069,7 @@ struct attr *bgp_attr_default_set(struct attr *attr, struct bgp *bgp,
 
 	attr->origin = origin;
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_ORIGIN);
-	attr->aspath = aspath_empty();
+	attr->aspath = aspath_empty(bgp->asnotation);
 	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_AS_PATH);
 	attr->weight = BGP_ATTR_DEFAULT_WEIGHT;
 	attr->tag = 0;
@@ -1107,7 +1107,7 @@ struct attr *bgp_attr_aggregate_intern(
 	if (aspath)
 		attr.aspath = aspath_intern(aspath);
 	else
-		attr.aspath = aspath_empty();
+		attr.aspath = aspath_empty(bgp->asnotation);
 	attr.flag |= ATTR_FLAG_BIT(BGP_ATTR_AS_PATH);
 
 	/* Next hop attribute.  */
@@ -1605,15 +1605,19 @@ static int bgp_attr_aspath(struct bgp_attr_parser_args *args)
 	struct attr *const attr = args->attr;
 	struct peer *const peer = args->peer;
 	const bgp_size_t length = args->length;
+	enum asnotation_mode asnotation;
 
+	asnotation = bgp_get_asnotation(
+		args->peer && args->peer->bgp ? args->peer->bgp : NULL);
 	/*
 	 * peer with AS4 => will get 4Byte ASnums
 	 * otherwise, will get 16 Bit
 	 */
-	attr->aspath = aspath_parse(
+	attr->aspath =
-		peer->curr, length,
+		aspath_parse(peer->curr, length,
-		CHECK_FLAG(peer->cap, PEER_CAP_AS4_RCV)
+			     CHECK_FLAG(peer->cap, PEER_CAP_AS4_RCV) &&
-			&& CHECK_FLAG(peer->cap, PEER_CAP_AS4_ADV));
+				     CHECK_FLAG(peer->cap, PEER_CAP_AS4_ADV),
+			     asnotation);
 
 	/* In case of IBGP, length will be zero. */
 	if (!attr->aspath) {
@@ -1705,8 +1709,11 @@ static int bgp_attr_as4_path(struct bgp_attr_parser_args *args,
 	struct peer *const peer = args->peer;
 	struct attr *const attr = args->attr;
 	const bgp_size_t length = args->length;
+	enum asnotation_mode asnotation;
 
-	*as4_path = aspath_parse(peer->curr, length, 1);
+	asnotation = bgp_get_asnotation(peer->bgp);
+
+	*as4_path = aspath_parse(peer->curr, length, 1, asnotation);
 
 	/* In case of IBGP, length will be zero. */
 	if (!*as4_path) {

bgpd/bgp_btoa.c

@@ -101,7 +101,8 @@ static void attr_parse(struct stream *s, uint16_t len)
 		case BGP_ATTR_AS_PATH: {
 			struct aspath *aspath;
 
-			aspath = aspath_parse(s, length, 1);
+			aspath = aspath_parse(s, length, 1,
+					      bgp_get_asnotation(NULL));
 			printf("ASPATH: %s\n", aspath->str);
 			aspath_free(aspath);
 		} break;

bgpd/bgp_route.c

@@ -7246,7 +7246,7 @@ static bool aggr_suppress_map_test(struct bgp *bgp,
 		return false;
 
 	/* Call route map matching and return result. */
-	attr.aspath = aspath_empty();
+	attr.aspath = aspath_empty(bgp->asnotation);
 	rmap_path.peer = bgp->peer_self;
 	rmap_path.attr = &attr;
 
@@ -7340,9 +7340,12 @@ static bool bgp_aggregate_info_same(struct bgp_path_info *pi, uint8_t origin,
 				    struct lcommunity *lcomm)
 {
 	static struct aspath *ae = NULL;
+	enum asnotation_mode asnotation;
+
+	asnotation = bgp_get_asnotation(NULL);
 
 	if (!ae)
-		ae = aspath_empty();
+		ae = aspath_empty(asnotation);
 
 	if (!pi)
 		return false;

bgpd/bgp_routemap.c

@@ -228,7 +228,7 @@ static void *route_aspath_compile(const char *arg)
 {
 	struct aspath *aspath;
 
-	aspath = aspath_str2aspath(arg);
+	aspath = aspath_str2aspath(arg, bgp_get_asnotation(NULL));
 	if (!aspath)
 		return NULL;
 	return aspath;

bgpd/bgp_script.c

@@ -163,7 +163,8 @@ void lua_decode_attr(lua_State *L, int idx, struct attr *attr)
 	attr->nh_ifindex = lua_tointeger(L, -1);
 	lua_pop(L, 1);
 	lua_getfield(L, idx, "aspath");
-	attr->aspath = aspath_str2aspath(lua_tostring(L, -1));
+	attr->aspath = aspath_str2aspath(lua_tostring(L, -1),
+					 bgp_get_asnotation(NULL));
 	lua_pop(L, 1);
 	lua_getfield(L, idx, "localpref");
 	attr->local_pref = lua_tointeger(L, -1);

bgpd/bgpd.c

@@ -2060,6 +2060,13 @@ const char *bgp_get_name_by_role(uint8_t role)
 	return "unknown";
 }
 
+enum asnotation_mode bgp_get_asnotation(struct bgp *bgp)
+{
+	if (!bgp)
+		return ASNOTATION_PLAIN;
+	return bgp->asnotation;
+}
+
 static void peer_group2peer_config_copy_af(struct peer_group *group,
 					   struct peer *peer, afi_t afi,
 					   safi_t safi)

bgpd/bgpd.h

@@ -2350,6 +2350,7 @@ extern void peer_tx_shutdown_message_unset(struct peer *);
 
 extern void bgp_route_map_update_timer(struct thread *thread);
 extern const char *bgp_get_name_by_role(uint8_t role);
+extern enum asnotation_mode bgp_get_asnotation(struct bgp *bgp);
 
 extern void bgp_route_map_terminate(void);
 

lib/asn.c

@@ -118,6 +118,15 @@ static bool asn_str2asn_internal(const char *asstring, as_t *asn,
 	return ret;
 }
 
+static void asn_asn2asdot(as_t asn, char *asstring, size_t len)
+{
+	uint16_t low, high;
+
+	high = (asn >> 16) & 0xffff;
+	low = asn & 0xffff;
+	snprintf(asstring, len, "%hu.%hu", high, low);
+}
+
 bool asn_str2asn(const char *asstring, as_t *asn)
 {
 	return asn_str2asn_internal(asstring, asn, NULL, NULL, NULL);
@@ -173,3 +182,58 @@ const char *asn_mode2str(enum asnotation_mode asnotation)
 	return lookup_msg(asnotation_mode_msg, asnotation,
 			  "Unrecognized AS notation mode");
 }
+
+void asn_asn2json_array(json_object *jseg_list, as_t asn,
+			enum asnotation_mode asnotation)
+{
+	static char as_str[ASN_STRING_MAX_SIZE];
+
+	if ((asnotation == ASNOTATION_PLAIN) ||
+	    ((asnotation == ASNOTATION_DOT) && asn < UINT16_MAX))
+		json_object_array_add(jseg_list,
+				      json_object_new_int64(asn));
+	else {
+		asn_asn2asdot(asn, as_str, sizeof(as_str));
+		json_array_string_add(jseg_list, as_str);
+	}
+}
+
+static ssize_t printfrr_asnotation(struct fbuf *buf, struct printfrr_eargs *ea,
+				   const void *ptr,
+				   enum asnotation_mode asnotation)
+{
+	/* for alignemnt up to 33 chars - %33pASD for instance - */
+	char as_str[ASN_STRING_MAX_SIZE*3];
+	const as_t *asn;
+
+	if (!ptr)
+		return bputs(buf, "(null)");
+	asn = ptr;
+	if ((asnotation == ASNOTATION_PLAIN) ||
+	    ((asnotation == ASNOTATION_DOT) && *asn < UINT16_MAX))
+		snprintf(as_str, sizeof(as_str), "%u", *asn);
+	else
+		asn_asn2asdot(*asn, as_str, sizeof(as_str));
+	return bputs(buf, as_str);
+}
+
+printfrr_ext_autoreg_p("ASP", printfrr_asplain);
+static ssize_t printfrr_asplain(struct fbuf *buf, struct printfrr_eargs *ea,
+				const void *ptr)
+{
+	return printfrr_asnotation(buf, ea, ptr, ASNOTATION_PLAIN);
+}
+
+printfrr_ext_autoreg_p("ASD", printfrr_asdot);
+static ssize_t printfrr_asdot(struct fbuf *buf, struct printfrr_eargs *ea,
+				const void *ptr)
+{
+	return printfrr_asnotation(buf, ea, ptr, ASNOTATION_DOT);
+}
+
+printfrr_ext_autoreg_p("ASE", printfrr_asdotplus);
+static ssize_t printfrr_asdotplus(struct fbuf *buf, struct printfrr_eargs *ea,
+				  const void *ptr)
+{
+	return printfrr_asnotation(buf, ea, ptr, ASNOTATION_DOTPLUS);
+}

lib/asn.h

@@ -24,6 +24,7 @@
 
 #include "zebra.h"
 #include "command_match.h"
+#include "json.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -48,6 +49,20 @@ extern enum match_type asn_str2asn_match(const char *str);
 extern bool asn_str2asn_notation(const char *asstring, as_t *asn,
 				 enum asnotation_mode *asnotation);
 extern const char *asn_mode2str(enum asnotation_mode asnotation);
+void asn_asn2json_array(json_object *jseg_list, as_t asn,
+			enum asnotation_mode asnotation);
+/* display AS in appropriate format */
+#ifdef _FRR_ATTRIBUTE_PRINTFRR
+#pragma FRR printfrr_ext "%pASP"  (as_t *)
+#pragma FRR printfrr_ext "%pASD"  (as_t *)
+#pragma FRR printfrr_ext "%pASE"  (as_t *)
+#endif
+
+#define ASN_FORMAT(mode)  \
+	((mode == ASNOTATION_DOT) ? "%pASD" :	    \
+	 ((mode == ASNOTATION_DOTPLUS) ? "%pASE" :	\
+	  "%pASP"))
+
 /* for test */
 extern void asn_relax_as_zero(bool relax);
 

tests/bgpd/test_aspath.c

@@ -880,7 +880,7 @@ static struct aspath *make_aspath(const uint8_t *data, size_t len, int use32bit)
 		s = stream_new(len);
 		stream_put(s, data, len);
 	}
-	as = aspath_parse(s, len, use32bit);
+	as = aspath_parse(s, len, use32bit, ASNOTATION_PLAIN);
 
 	if (s)
 		stream_free(s);
@@ -925,7 +925,7 @@ static int validate(struct aspath *as, const struct test_spec *sp)
 	as4 = make_aspath(STREAM_DATA(s), bytes4, 1);
 
 	asn_relax_as_zero(true);
-	asstr = aspath_str2aspath(sp->shouldbe);
+	asstr = aspath_str2aspath(sp->shouldbe, ASNOTATION_PLAIN);
 	asn_relax_as_zero(false);
 
 	asconfeddel = aspath_delete_confed_seq(aspath_dup(asinout));
@@ -1103,7 +1103,7 @@ static void empty_prepend_test(struct test_segment *t)
 	printf("empty prepend %s: %s\n", t->name, t->desc);
 
 	asp1 = make_aspath(t->asdata, t->len, 0);
-	asp2 = aspath_empty();
+	asp2 = aspath_empty(ASNOTATION_PLAIN);
 
 	ascratch = aspath_dup(asp2);
 	aspath_unintern(&asp2);

tests/lib/test_printfrr.c

@@ -25,6 +25,7 @@
 #include "lib/memory.h"
 #include "lib/prefix.h"
 #include "lib/nexthop.h"
+#include "lib/asn.h"
 
 static int errors;
 
@@ -158,6 +159,7 @@ int main(int argc, char **argv)
 	struct in_addr ip;
 	char *p;
 	char buf[256];
+	as_t asn;
 
 	printcmp("%d %u %d %u", 123, 123, -456, -456);
 	printcmp("%lld %llu %lld %llu", 123LL, 123LL, -456LL, -456LL);
@@ -405,6 +407,13 @@ int main(int argc, char **argv)
 	printchk("-00:09", "%pTSIm", &ts);
 	printchk("--:--", "%pTVImx", &tv);
 	printchk("--:--", "%pTTImx", &tt);
+	/* ASN checks */
+	asn = 65536;
+	printchk("1.0", "%pASD", &asn);
+	asn = 65400;
+	printchk("65400", "%pASP", &asn);
+	printchk("0.65400", "%pASE", &asn);
+	printchk("65400", "%pASD", &asn);
 
 	return !!errors;
 }