libknot: add EDNS ZONEVERSION support

4 files changed, 98 insertions, 8 deletions

diff --git a/src/libknot/codes.c b/src/libknot/codes.c
index b0b78faa6..cece38a85 100644
--- a/src/libknot/codes.c
+++ b/src/libknot/codes.c
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2024 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -142,5 +142,6 @@ const knot_lookup_t knot_edns_opt_names[] = {
 	{ KNOT_EDNS_OPTION_PADDING,       "PADDING" },
 	{ KNOT_EDNS_OPTION_CHAIN,         "CHAIN" },
 	{ KNOT_EDNS_OPTION_EDE,           "EDE" },
+	{ KNOT_EDNS_OPTION_ZONEVERSION,   "ZONEVERSION" },
 	{ 0, NULL }
 };
diff --git a/src/libknot/rrset-dump.c b/src/libknot/rrset-dump.c
index 9fac99dc6..f1f5b3762 100644
--- a/src/libknot/rrset-dump.c
+++ b/src/libknot/rrset-dump.c
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2024 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -1172,6 +1172,9 @@ static void wire_ednsoptval_to_str(rrset_dump_params_t *p, uint16_t opt, uint16_
 		CHECK_PRET
 		wire_text_to_str(p, len - sizeof(uint16_t), "", true, false);
 		break;
+	case KNOT_EDNS_OPTION_ZONEVERSION:
+		wire_data_to_hex(p, len); // not fully implemented, don't know QNAME
+		break;
 	default:
 		assert(0); // this should be handled in wire_ednsopt_to_str() by generic OPT##=hex
 		break;
diff --git a/src/libknot/rrtype/opt.c b/src/libknot/rrtype/opt.c
index 294689c2d..ebdf836b0 100644
--- a/src/libknot/rrtype/opt.c
+++ b/src/libknot/rrtype/opt.c
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -685,3 +685,53 @@ int knot_edns_cookie_parse(knot_edns_cookie_t *cc, knot_edns_cookie_t *sc,
 
 	return KNOT_EOK;
 }
+
+_public_
+int knot_edns_zoneversion_parse(knot_dname_storage_t zone, uint8_t *type,
+                                uint32_t *version, const uint8_t *option,
+                                uint16_t option_len, const knot_dname_t *qname)
+{
+	if (zone == NULL || type == NULL || version == NULL || option == NULL ||
+	    qname == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	if (option_len == 0) {
+		return KNOT_ENOENT;
+	} else if (option_len != KNOT_EDNS_ZONEVERSION_LENGTH) {
+		return KNOT_EMALF;
+	}
+
+	wire_ctx_t wire = wire_ctx_init_const(option, option_len);
+	uint8_t labels = wire_ctx_read_u8(&wire);
+	*type = wire_ctx_read_u8(&wire);
+	*version = wire_ctx_read_u32(&wire);
+
+	size_t qname_labels = knot_dname_labels(qname, NULL);
+	if (labels > qname_labels) {
+		return KNOT_EMALF;
+	}
+	size_t prefix_size = knot_dname_prefixlen(qname, qname_labels - labels);
+	size_t qname_size = knot_dname_size(qname);
+	memcpy(zone, qname + prefix_size, qname_size - prefix_size);
+
+	return wire.error;
+}
+
+_public_
+int knot_edns_zoneversion_write(uint8_t *option, uint16_t option_len, uint8_t type,
+                                const knot_dname_t *zone, uint32_t version)
+{
+	if (option == NULL || zone == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	size_t labels = knot_dname_labels(zone, NULL);
+
+	wire_ctx_t wire = wire_ctx_init(option, option_len);
+	wire_ctx_write_u8(&wire, labels);
+	wire_ctx_write_u8(&wire, type);
+	wire_ctx_write_u32(&wire, version);
+
+	return wire.error;
+}
diff --git a/src/libknot/rrtype/opt.h b/src/libknot/rrtype/opt.h
index bce87c20c..48285ed4a 100644
--- a/src/libknot/rrtype/opt.h
+++ b/src/libknot/rrtype/opt.h
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -71,6 +71,14 @@ enum {
 	/*! \brief EDNS maximum server cookie size. */
 	KNOT_EDNS_COOKIE_SRVR_MAX_SIZE = 32,
 
+	/*! \brief The minimal length for EDE option including option header. */
+	KNOT_EDNS_EDE_MIN_LENGTH       = 6,
+
+	/*! \brief The SOA serial version type. */
+	KNOT_EDNS_ZONEVERSION_TYPE_SOA = 0,
+	/*! \brief The length of ZONEVERSION in a response. */
+	KNOT_EDNS_ZONEVERSION_LENGTH   = 6,
+
 	/*! \brief NSID option code. */
 	KNOT_EDNS_OPTION_NSID          = 3,
 	/*! \brief EDNS Client subnet option code. */
@@ -85,14 +93,13 @@ enum {
 	KNOT_EDNS_OPTION_PADDING       = 12,
 	/*! \brief EDNS Chain query option code. */
 	KNOT_EDNS_OPTION_CHAIN         = 13,
-
 	/*! \brief EDNS Extended error code. */
 	KNOT_EDNS_OPTION_EDE           = 15,
-	/*! \brief The minimal length for EDE option including option header. */
-	KNOT_EDNS_EDE_MIN_LENGTH       = 6,
+	/*! \brief EDNS Zone version option code. */
+	KNOT_EDNS_OPTION_ZONEVERSION   = 19,
 
 	/*! \brief Maximal currently known option code. */
-	KNOT_EDNS_MAX_OPTION_CODE      = 17,
+	KNOT_EDNS_MAX_OPTION_CODE      = 19,
 };
 
 /* Helpers for splitting extended RCODE. */
@@ -584,4 +591,33 @@ int knot_edns_cookie_write(uint8_t *option, uint16_t option_len,
 int knot_edns_cookie_parse(knot_edns_cookie_t *cc, knot_edns_cookie_t *sc,
                            const uint8_t *option, uint16_t option_len);
 
+/*!
+ * \brief Writes EDNS Zone version wire data.
+ *
+ * \param[out] option      EDNS option data buffer.
+ * \param[in]  option_len  EDNS option data buffer size.
+ * \param[in]  type        The version type.
+ * \param[in]  zone        Zone name.
+ * \param[in]  version     The zone version.
+ *
+ * \return Error code, KNOT_EOK if successful or KNOT_ENOENT if no data.
+ */
+int knot_edns_zoneversion_write(uint8_t *option, uint16_t option_len, uint8_t type,
+                                const knot_dname_t *zone, uint32_t version);
+
+/*!
+ * \brief Parses EDNS Zone version wire data.
+ *
+ * \param[out] labels      The QNAME labels.
+ * \param[out] type        The version type.
+ * \param[out] version     The zone version.
+ * \param[in]  option      EDNS option data.
+ * \param[in]  option_len  EDNS option size.
+ *
+ * \return Error code, KNOT_EOK if successful.
+ */
+int knot_edns_zoneversion_parse(knot_dname_storage_t zone, uint8_t *type,
+                                uint32_t *version, const uint8_t *option,
+                                uint16_t option_len, const knot_dname_t *qname);
+
 /*! @} */