Maintained by: NLnet Labs

[Unbound-users] Patch for access to full DNS packet data in unbound python module

Ondrej Mikle
Fri Mar 16 15:33:33 CET 2012


Hi,

I'm sending patch to access full DNS packet data using python module
"unbound". I couldn't figure out how to access NSEC3 and RRSIG from
answer packet without it (ldns.ldns_wire2pkt takes python string).

Patch and test code attached.

Ondrej
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#!/usr/bin/env python
from unbound import ub_ctx, RR_TYPE_A, RR_TYPE_RRSIG, RR_TYPE_NSEC, RR_TYPE_NSEC3
import ldns

def dnssecParse(domain, rrType=RR_TYPE_A):
    print "Resolving domain", domain
    s, r = resolver.resolve(domain)
    print "status: %s, secure: %s, rcode: %s, havedata: %s, answer_len; %s" % (s, r.secure, r.rcode_str, r.havedata, r.answer_len)
    
    s, pkt = ldns.ldns_wire2pkt(r.packet)
    if s != 0:
        raise RuntimeError("Error parsing DNS packet")

    rrsigs = pkt.rr_list_by_type(RR_TYPE_RRSIG, ldns.LDNS_SECTION_ANSWER)
    print "RRSIGs from answer:", rrsigs
    
    rrsigs = pkt.rr_list_by_type(RR_TYPE_RRSIG, ldns.LDNS_SECTION_AUTHORITY)
    print "RRSIGs from authority:", rrsigs
    
    nsecs = pkt.rr_list_by_type(RR_TYPE_NSEC, ldns.LDNS_SECTION_AUTHORITY)
    print "NSECs:", nsecs
    
    nsec3s = pkt.rr_list_by_type(RR_TYPE_NSEC3, ldns.LDNS_SECTION_AUTHORITY)
    print "NSEC3s:", nsec3s
    
    print "---"


resolver = ub_ctx()
resolver.add_ta(".   IN DS   19036 8 2 49AAC11D7B6F6446702E54A1607371607A1A41855200FD2CE1CDDE32F24E8FB5")

dnssecParse("nic.cz")
dnssecParse("nonexistent-domain-blablabla.cz")
dnssecParse("nonexistent-domain-blablabla.root.cz")