bind9/bin/plugins/dynptrr.c

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#include <ns/hooks.h>
#include <dns/view.h>
#include <dns/rdatalist.h>
#include <dns/byaddr.h>

typedef struct dynptrr dynptrr_t;
struct dynptrr {
	isc_mem_t *mctx;
};

static ns_hookresult_t
dynptrr_nxdomain_begin(void *arg, void *cbdata, isc_result_t *resp) {
	query_ctx_t *qctx = (query_ctx_t *)arg;
	isc_mem_t *mctx = qctx->client->view->mctx;
	dynptrr_t *inst = (dynptrr_t *)cbdata;
	UNUSED(inst);
	
	*resp = ISC_R_UNSET;
	if (qctx->type != dns_rdatatype_ptr) {
		return NS_HOOK_CONTINUE;
	}
	isc_log_write(NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
		      ISC_LOG_DEBUG(1), "dynptrr nxdomain begin");

	dns_message_t *message = qctx->client->message;

	dns_name_t *name = isc_mem_get(mctx, sizeof(*name));
	dns_rdataset_t *synth = NULL;
	dns_rdatalist_t *synthlist = NULL;
	dns_rdata_t *synthdata = NULL;

	dns_name_init(name);
	dns_name_dup(qctx->client->query.qname, mctx, name);	
	char n[512];
	dns_name_format(name, n, 512);
	isc_log_write(NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
			ISC_LOG_DEBUG(1), "dynptrr %s", n);

	dns_message_gettemprdataset(message, &synth);
	dns_rdataset_init(synth);
	synth->ttl = 60;
	synth->rdclass = dns_rdataclass_in;
	synth->type = dns_rdatatype_ptr;

	dns_message_gettemprdatalist(message, &synthlist);
	dns_rdatalist_init(synthlist);
	synthlist->ttl = 60;
	synthlist->rdclass = dns_rdataclass_in;
	synthlist->type = dns_rdatatype_ptr;

	dns_message_gettemprdata(message, &synthdata);
	dns_rdata_init(synthdata);
	synthdata->rdclass = dns_rdataclass_in;
	synthdata->type = dns_rdatatype_ptr;

	/*
	 * It seems that for a ptr type, the data must be the ndata pointer of a
	 * dns_name_t. (I attempted putting a raw string instead, and it was a
	 * crash)
	 */
	synthdata->data = name->ndata;
	synthdata->length = name->length;

	ISC_LIST_APPEND(synthlist->rdata, synthdata, link);

	dns_rdatalist_tordataset(synthlist, synth);
	dns_rdataset_setownercase(synth, name);
	dns_message_addname(message, name, DNS_SECTION_ANSWER);
	ISC_LIST_APPEND(name->list, synth, link);

	isc_result_t result = ns_query_done(qctx);
	*resp = result;

	/* ------------------------------------------------- */

//	isc_netaddr_t peeraddr;
//	isc_netaddr_fromsockaddr(&peeraddr, &qctx->client->peeraddr);
//
//	char createdptrnamed[512];
//	isc_buffer_t createdptrnameb;
//	isc_buffer_init(&createdptrnameb, createdptrnamed, 512);
//
//	dns_name_t *createdptrname = isc_mem_get(mctx, sizeof(*createdptrname));
//	dns_name_init(createdptrname);
//	dns_name_setbuffer(createdptrname, &createdptrnameb);
//	isc_result_t r = dns_byaddr_createptrname(&peeraddr, createdptrname);
//	isc_log_write(NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
//		      ISC_LOG_DEBUG(1), "dynptrr %s", isc_result_totext(r));
//	dns_name_format(createdptrname, n, 512);
//	isc_log_write(NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
//			ISC_LOG_DEBUG(1), "dynptrr ptr %s", n);
//	isc_mem_put(mctx, createdptrname, sizeof(*createdptrname));
//
	/* ------------------------------------------------- */

	return NS_HOOK_RETURN;
}


void
plugin_destroy(void **instp) {
	REQUIRE(instp && *instp);

	dynptrr_t *inst = *instp;
	isc_mem_t *mctx = inst->mctx;
	isc_mem_put(mctx, inst, sizeof(*inst));
	*instp = NULL;

	printf("dynptrr plugin_destroy\n");
}

int
plugin_version(void) {
	printf("dynptrr plugin_version\n");
	return NS_PLUGIN_VERSION;
}

isc_result_t                   
plugin_register(const char *parameters, const void *cfg, const char *cfg_file,
                unsigned long cfg_line, isc_mem_t *mctx, void *actx,
                ns_hooktable_t *hooktable, void **instp) {
	REQUIRE(cfg);
	REQUIRE(mctx);
	REQUIRE(actx);
	REQUIRE(hooktable);
	REQUIRE(instp && *instp == NULL);

	printf("dynptrr plugin_register %s %s %ld\n", parameters, cfg_file,
	       cfg_line);

	dynptrr_t *inst = isc_mem_get(mctx, sizeof(*inst));
	*inst = (dynptrr_t){ .mctx = mctx };
	*instp = inst;

	const ns_hook_t testhook = {
		.action = dynptrr_nxdomain_begin,
		.action_data = inst 
	};
	ns_hook_add(hooktable, mctx, NS_QUERY_NXDOMAIN_BEGIN, &testhook);

	return ISC_R_SUCCESS;
}

isc_result_t
plugin_check(const char *parameters, const void *cfg, const char *cfg_file,
             unsigned long cfg_line, isc_mem_t *mctx, void *actx) {
	REQUIRE(cfg);
	REQUIRE(mctx);
	REQUIRE(actx);

	printf("dynptrr plugin_check %s %s %ld\n", parameters, cfg_file,
	       cfg_line);
	return ISC_R_SUCCESS;
}