lib, bgp: add initial support for asdot format

AS number can be defined as an unsigned long number, or
two uint16 values separated by a period (.). The possible
valus are:
- usual 32 bit values : [1;2^32 -1]
- <1.65535>.<0.65535> for dot notation
- <0.65535>.<0.65535> for dot+ notation.

The 0.0 value is forbidden when configuring BGP instances
or peer configurations.

A new ASN type is added for parsing in the vty.
The following commands use that new identifier:
- router bgp ..
- bgp confederation ..
- neighbor <> remote-as <>
- neighbor <> local-as <>
- clear ip bgp <>
- route-map / set as-path <>

An asn library is available in lib/ and provides some
services:
- convert an as string into an as number.
- parse an as path list string and extract a number.
- convert an as number into a string.

Also, the bgp tests forge an as_zero_path, and to do that,
an API to relax the possibility to have a 0 as value is
specifically called from the tests.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/python/clidef.py b/python/clidef.py
index 101c9a5ae..cd399e93b 100644
--- a/python/clidef.py
+++ b/python/clidef.py
@@ -64,6 +64,12 @@ _fail = (_end == argv[_i]->arg) || (*_end != '\\0');"""
     )
 
 
+class AsDotHandler(RenderHandler):
+    argtype = "as_t"
+    decl = Template("as_t $varname = 0;")
+    code = Template("_fail = !asn_str2asn(argv[_i]->arg, &$varname);")
+
+
 # A.B.C.D/M (prefix_ipv4) and
 # X:X::X:X/M (prefix_ipv6) are "compatible" and can merge into a
 # struct prefix:
@@ -165,6 +171,7 @@ handlers = {
     "IPV6_PREFIX_TKN": Prefix6Handler,
     "MAC_TKN": PrefixEthHandler,
     "MAC_PREFIX_TKN": PrefixEthHandler,
+    "ASNUM_TKN": AsDotHandler,
 }
 
 # core template invoked for each occurence of DEFPY.