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>

1 files changed, 64 insertions, 0 deletions

diff --git a/lib/asn.c b/lib/asn.c
index 502854ec95..4c37cca1f6 100644
--- a/lib/asn.c
+++ b/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);
+}