From ce6078d2b9d65bc9727ff0799117d34bdf0ca56c Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Sat, 26 Jul 2025 06:17:20 +0200
Subject: [PATCH] Add support for parsing DSYNC scheme mnemonics

Adds dns_dsyncscheme_fromtext, dns_dsyncscheme_totext and
dns_dsyncscheme_format.  Adds type dns_dsyncscheme_t.

(cherry picked from commit 6e1311c624d15e6c4d0184deea3bb670e8a5785d)
---
 lib/dns/Makefile.am         |  3 ++-
 lib/dns/include/dns/dsync.h | 27 +++++++++++++++++++++++
 lib/dns/include/dns/types.h |  1 +
 lib/dns/rcode.c             | 43 +++++++++++++++++++++++++++++++++++++
 4 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 lib/dns/include/dns/dsync.h

diff --git a/lib/dns/Makefile.am b/lib/dns/Makefile.am
index 3428131fcc..49553d0332 100644
--- a/lib/dns/Makefile.am
+++ b/lib/dns/Makefile.am
@@ -67,9 +67,10 @@ libdns_la_HEADERS =			\
 	include/dns/dns64.h		\
 	include/dns/dnsrps.h		\
 	include/dns/dnssec.h		\
+	include/dns/dnstap.h		\
 	include/dns/ds.h		\
 	include/dns/dsdigest.h		\
-	include/dns/dnstap.h		\
+	include/dns/dsync.h		\
 	include/dns/dyndb.h		\
 	include/dns/ecs.h		\
 	include/dns/ede.h		\
diff --git a/lib/dns/include/dns/dsync.h b/lib/dns/include/dns/dsync.h
new file mode 100644
index 0000000000..9533d4c2e5
--- /dev/null
+++ b/lib/dns/include/dns/dsync.h
@@ -0,0 +1,27 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#define DNS_DSYNCSCHEME_NOTIFY (1)
+
+#define DNS_DSYNCSCHEMEFORMAT_SIZE (7)
+
+isc_result_t
+dns_dsyncscheme_fromtext(dns_dsyncscheme_t *schemep, isc_textregion_t *source);
+
+isc_result_t
+dns_dsyncscheme_totext(dns_dsyncscheme_t scheme, isc_buffer_t *target);
+
+void
+dns_dsyncscheme_format(dns_dsyncscheme_t scheme, char *cp, unsigned int size);
diff --git a/lib/dns/include/dns/types.h b/lib/dns/include/dns/types.h
index 6b124bf734..6cd5085478 100644
--- a/lib/dns/include/dns/types.h
+++ b/lib/dns/include/dns/types.h
@@ -80,6 +80,7 @@ typedef ISC_LIST(dns_dns64_t) dns_dns64list_t;
 typedef struct dns_dnsseckey dns_dnsseckey_t;
 typedef ISC_LIST(dns_dnsseckey_t) dns_dnsseckeylist_t;
 typedef uint8_t			   dns_dsdigest_t;
+typedef uint8_t			   dns_dsyncscheme_t;
 typedef struct dns_dtdata	   dns_dtdata_t;
 typedef struct dns_dtenv	   dns_dtenv_t;
 typedef struct dns_dtmsg	   dns_dtmsg_t;
diff --git a/lib/dns/rcode.c b/lib/dns/rcode.c
index 6c957e870c..e2a7309664 100644
--- a/lib/dns/rcode.c
+++ b/lib/dns/rcode.c
@@ -29,6 +29,7 @@
 #include <dns/cert.h>
 #include <dns/ds.h>
 #include <dns/dsdigest.h>
+#include <dns/dsync.h>
 #include <dns/keyflags.h>
 #include <dns/keyvalues.h>
 #include <dns/rcode.h>
@@ -47,6 +48,10 @@
 
 #define TOTEXTONLY 0x01
 
+/* clang-format off */
+#define SENTINEL { 0, NULL, 0 }
+/* clang-format on */
+
 #define RCODENAMES                                     \
 	/* standard rcodes */                          \
 	{ dns_rcode_noerror, "NOERROR", 0 },           \
@@ -130,6 +135,8 @@
 		{ DNS_DSDIGEST_SHA384, "SHA-384", 0 },                       \
 		{ DNS_DSDIGEST_SHA384, "SHA384", 0 }, { 0, NULL, 0 }
 
+#define DSYNCSCHEMES { DNS_DSYNCSCHEME_NOTIFY, "NOTIFY", 0 }, SENTINEL
+
 struct tbl {
 	unsigned int value;
 	const char *name;
@@ -143,6 +150,7 @@ static struct tbl secalgs[] = { SECALGNAMES };
 static struct tbl secprotos[] = { SECPROTONAMES };
 static struct tbl hashalgs[] = { HASHALGNAMES };
 static struct tbl dsdigests[] = { DSDIGESTNAMES };
+static struct tbl dsyncschemes[] = { DSYNCSCHEMES };
 
 static struct keyflag {
 	const char *name;
@@ -450,6 +458,41 @@ dns_dsdigest_format(dns_dsdigest_t typ, char *cp, unsigned int size) {
 	}
 }
 
+/*
+ * DSYNC Scheme
+ */
+
+isc_result_t
+dns_dsyncscheme_fromtext(dns_dsyncscheme_t *schemep, isc_textregion_t *source) {
+	unsigned int value;
+
+	REQUIRE(schemep != NULL);
+	RETERR(dns_mnemonic_fromtext(&value, source, dsyncschemes, 0xff));
+	*schemep = value;
+	return ISC_R_SUCCESS;
+}
+
+isc_result_t
+dns_dsyncscheme_totext(dns_dsyncscheme_t scheme, isc_buffer_t *target) {
+	return dns_mnemonic_totext(scheme, target, dsyncschemes);
+}
+
+void
+dns_dsyncscheme_format(dns_dsyncscheme_t scheme, char *cp, unsigned int size) {
+	isc_buffer_t b;
+	isc_region_t r;
+	isc_result_t result;
+
+	REQUIRE(cp != NULL && size > 0);
+	isc_buffer_init(&b, cp, size - 1);
+	result = dns_dsyncscheme_totext(scheme, &b);
+	isc_buffer_usedregion(&b, &r);
+	r.base[r.length] = 0;
+	if (result != ISC_R_SUCCESS) {
+		r.base[0] = 0;
+	}
+}
+
 /*
  * This uses lots of hard coded values, but how often do we actually
  * add classes?