fix: populate ldns submodule and add autotools to LDNS build stage

- Re-cloned zonemaster-ldns with --recurse-submodules so the bundled
  ldns C library source (including Changelog and configure.ac) is present
- Added autoconf, automake, libtool to Dockerfile.backend ldns-build stage
  so libtoolize + autoreconf can generate ldns/configure during make

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

zonemaster-ldns/ldns/masterdont/process.c

@@ -0,0 +1,193 @@
+#include "config.h"
+#include "process.h"
+#include "zones.h"
+#include "zinfo.h"
+#include "server.h"
+
+ldns_pkt_rcode 
+process_pkts(struct socket_service* sv, ldns_pkt* q, ldns_pkt* r,
+	struct zones_t* zones)
+{
+	if(ldns_pkt_edns(q)) {
+		ldns_pkt_set_edns_do(r, ldns_pkt_edns_do(q));
+		ldns_pkt_set_edns_udp_size(r, 4096);
+	}
+	if(ldns_pkt_tsig(q)) {
+		printf("tsig todo\n");
+	}
+
+	switch(ldns_pkt_get_opcode(q)) {
+	case LDNS_PACKET_QUERY:
+		return process_pkt_query(sv, q, r, zones);
+	case LDNS_PACKET_NOTIFY:
+		return process_pkt_notify(sv, q, r, zones);
+	default:
+		return LDNS_RCODE_NOTIMPL;
+	}
+}
+
+ldns_pkt_rcode 
+process_pkt_notify(struct socket_service* sv, ldns_pkt* q, ldns_pkt* r,
+	struct zones_t* zones)
+{
+	(void)(sv); (void)(q); (void)(r); (void)zones;
+	return LDNS_RCODE_NOTIMPL;
+}
+
+ldns_pkt_rcode 
+process_pkt_query(struct socket_service* sv, ldns_pkt* q, ldns_pkt* r,
+	struct zones_t* zones)
+{
+	ldns_rr *qrr;
+	struct zone_entry_t* entry ;
+
+	if(ldns_pkt_qdcount(q) != 1) /* one question */
+		return LDNS_RCODE_FORMERR;
+	qrr = ldns_rr_list_rr(ldns_pkt_question(q), 0);
+
+	/* find query name zone */
+	entry = zones_find_rdf(zones, ldns_rr_owner(qrr), 
+		ldns_rr_get_class(qrr));
+	if(!entry) {
+		return LDNS_RCODE_REFUSED;
+	}
+	printf("Got zone for q. %s\n", entry->zstr);
+
+	/* copy question */
+	ldns_pkt_push_rr(r, LDNS_SECTION_QUESTION, ldns_rr_clone(qrr));
+
+	switch(ldns_rr_get_type(qrr)) {
+	case LDNS_RR_TYPE_ANY:
+		ldns_pkt_set_aa(r, false);
+	case LDNS_RR_TYPE_SOA:
+		return process_pkt_soa(sv, q, r, entry);
+	case LDNS_RR_TYPE_AXFR:
+		return process_pkt_axfr(sv, entry);
+	case LDNS_RR_TYPE_IXFR:
+		return process_pkt_ixfr(sv, q, r, entry);
+	default:
+		return LDNS_RCODE_REFUSED;
+	}
+}
+
+ldns_pkt_rcode 
+process_pkt_soa(struct socket_service* sv, ldns_pkt* q, ldns_pkt* r,
+	struct zone_entry_t* entry)
+{
+	ldns_rr_list* soa = ldns_rr_list_clone(entry->zinfo->last_soa);
+	(void)sv; (void)q;
+	if(!soa) /* have zone but not soa; no data for zone */
+		return LDNS_RCODE_SERVFAIL;
+	/* put the answer into the packet */
+	ldns_pkt_push_rr_list(r, LDNS_SECTION_ANSWER, soa);
+	return LDNS_RCODE_NOERROR;
+}
+
+ldns_pkt_rcode 
+process_pkt_ixfr(struct socket_service* sv, ldns_pkt* q, ldns_pkt* r,
+	struct zone_entry_t* entry)
+{
+	uint32_t serial_from, serial_to;
+	ldns_rr_list *rr_add=0, *rr_remove=0;
+	ldns_rr *soa_from=0; 
+	ldns_rr_list *soa_to=0;
+
+	if(ldns_pkt_nscount(q) != 1 ||
+		ldns_rr_get_type(ldns_rr_list_rr(ldns_pkt_authority(q), 0))
+		!= LDNS_RR_TYPE_SOA) {
+		printf("ixfr without serial indication\n");
+		return LDNS_RCODE_FORMERR;
+	}
+	if(!entry->zinfo->is_present) {
+		printf("ixfr request for zone without data\n");
+		return LDNS_RCODE_SERVFAIL;
+	}
+
+	serial_to = entry->zinfo->last_serial;
+	serial_from = ldns_rdf2native_int32(ldns_rr_rdf(
+		ldns_rr_list_rr(ldns_pkt_authority(q), 0), 2));
+
+	soa_to = ldns_rr_list_clone(entry->zinfo->last_soa);
+	if(!soa_to) {
+		return LDNS_RCODE_SERVFAIL;
+	}
+
+	if(serial_to == serial_from) {
+		printf("ixfr request for latest version\n");
+		ldns_pkt_push_rr_list(r, LDNS_SECTION_ANSWER, soa_to);
+		return LDNS_RCODE_NOERROR;
+	}
+
+	/* if UDP - reply with SOA and TC indication */
+	if(!sv->is_tcp) {
+		ldns_pkt_set_tc(r, true);
+		ldns_pkt_push_rr_list(r, LDNS_SECTION_ANSWER, soa_to);
+		return LDNS_RCODE_NOERROR;
+	}
+
+	zinfo_get_zone_diff(entry, serial_from, serial_to, &rr_remove,
+		&rr_add, &soa_from, &soa_to);
+	if(!rr_remove || !rr_add || !soa_from || !soa_to) {
+		printf("get_zone_diff failed, fallback to AXFR\n");
+		return process_pkt_axfr(sv, entry);
+	}
+
+	/* create rrlist for reply */
+	if(sv->reply)
+		ldns_rr_list_deep_free(sv->reply);
+	sv->reply = ldns_rr_list_new();
+	if(!sv->reply) {
+		printf("out of memory\n");
+		return LDNS_RCODE_SERVFAIL;
+	}
+	/* a 'condensed' IXFR zone transfer (see RFC 1995) */
+	ldns_rr_list_push_rr(sv->reply, ldns_rr_clone(soa_to));
+	ldns_rr_list_push_rr(sv->reply, soa_from);
+	/* deletes */
+	ldns_rr_list_cat(sv->reply, rr_remove);
+	ldns_rr_list_push_rr(sv->reply, ldns_rr_clone(soa_to));
+	/* adds */
+	ldns_rr_list_cat(sv->reply, rr_add);
+	ldns_rr_list_push_rr(sv->reply, soa_to);
+
+	/* not deep free since rrs moved to the answer */
+	ldns_rr_list_free(rr_remove);
+	ldns_rr_list_free(rr_add);
+	/* do not need to delete soa_from, soa_to: they are in rrlist. */
+
+	return LDNS_RCODE_NOERROR;
+}
+
+ldns_pkt_rcode 
+process_pkt_axfr(struct socket_service* sv, struct zone_entry_t* entry)
+{
+	uint32_t serial;
+	ldns_zone* z = 0;
+
+	serial = entry->zinfo->last_serial;
+	zinfo_get_zone_full(entry, serial, &z);
+	if(!z) {
+		/* no data for this zone! */
+		printf("Could not get latest zone info for zone %s %u\n",
+			entry->zstr, serial);
+		return LDNS_RCODE_SERVFAIL;
+	}
+
+	/* create list of RRs in sv->rrlist */
+	if(sv->reply)
+		ldns_rr_list_deep_free(sv->reply);
+	sv->reply = ldns_rr_list_new();
+	if(!sv->reply) {
+		printf("out of memory\n");
+		return LDNS_RCODE_SERVFAIL;
+	}
+	/* move zone contents over */
+	ldns_rr_list_push_rr(sv->reply, ldns_rr_clone(ldns_zone_soa(z))); 
+	ldns_rr_list_cat(sv->reply, ldns_zone_rrs(z)); 
+	ldns_rr_list_push_rr(sv->reply, ldns_rr_clone(ldns_zone_soa(z)));
+
+	ldns_rr_list_set_rr_count(ldns_zone_rrs(z), 0);
+	ldns_zone_deep_free(z);
+
+	return LDNS_RCODE_NOERROR;
+}