zone: add request EDNS option support

doc/man/knot.conf.5in

@@ -482,6 +482,7 @@ zone:
     max\-journal\-size: SIZE
     dnssec\-signing: BOOL
     kasp\-db: STR
+    request\-edns\-option: INT:[HEXSTR]
     serial\-policy: increment | unixtime
     module: STR/STR ...
 .ft P
@@ -647,6 +648,12 @@ A KASP database path. Non absolute path is relative to
 \fI\%storage\fP\&.
 .sp
 Default: \fI\%storage\fP/keys
+.SS request\-edns\-option
+.sp
+An arbitrary EDNS0 option which is included into a server request (AXFR, IXFR,
+SOA, or NOTIFY). The value is in the option_code:option_data format.
+.sp
+Default: empty
 .SS serial\-policy
 .sp
 Specifies how the zone serial is updated after a dynamic update or

doc/reference.rst

@@ -562,6 +562,7 @@ Definition of zones served by the server.
      max-journal-size: SIZE
      dnssec-signing: BOOL
      kasp-db: STR
+     request-edns-option: INT:[HEXSTR]
      serial-policy: increment | unixtime
      module: STR/STR ...
 
@@ -759,6 +760,16 @@ A KASP database path. Non absolute path is relative to
 
 Default: :ref:`storage<zone_storage>`/keys
 
+.. _zone_request_edns_option:
+
+request-edns-option
+-------------------
+
+An arbitrary EDNS0 option which is included into a server request (AXFR, IXFR,
+SOA, or NOTIFY). The value is in the option_code:option_data format.
+
+Default: empty
+
 .. _zone_serial-policy:
 
 serial-policy

src/knot/conf/scheme.c

@@ -133,23 +133,24 @@ static const yp_item_t desc_remote[] = {
 };
 
 #define ZONE_ITEMS \
-	{ C_FILE,             YP_TSTR,  YP_VNONE }, \
-	{ C_STORAGE,          YP_TSTR,  YP_VSTR = { STORAGE_DIR } }, \
-	{ C_MASTER,           YP_TREF,  YP_VREF = { C_RMT }, YP_FMULTI, { check_ref } }, \
-	{ C_DDNS_MASTER,      YP_TREF,  YP_VREF = { C_RMT }, YP_FNONE, { check_ref } }, \
-	{ C_NOTIFY,           YP_TREF,  YP_VREF = { C_RMT }, YP_FMULTI, { check_ref } }, \
-	{ C_ACL,              YP_TREF,  YP_VREF = { C_ACL }, YP_FMULTI, { check_ref } }, \
-	{ C_SEM_CHECKS,       YP_TBOOL, YP_VNONE }, \
-	{ C_DISABLE_ANY,      YP_TBOOL, YP_VNONE }, \
-	{ C_ZONEFILE_SYNC,    YP_TINT,  YP_VINT = { -1, INT32_MAX, 0, YP_STIME } }, \
-	{ C_IXFR_DIFF,        YP_TBOOL, YP_VNONE }, \
-	{ C_MAX_JOURNAL_SIZE, YP_TINT,  YP_VINT = { 0, INT64_MAX, INT64_MAX, YP_SSIZE } }, \
-	{ C_DNSSEC_SIGNING,   YP_TBOOL, YP_VNONE }, \
-	{ C_KASP_DB,          YP_TSTR,  YP_VSTR = { "keys" } }, \
-	{ C_SERIAL_POLICY,    YP_TOPT,  YP_VOPT = { serial_policies, SERIAL_POLICY_INCREMENT } }, \
-	{ C_MODULE,           YP_TDATA, YP_VDATA = { 0, NULL, mod_id_to_bin, mod_id_to_txt }, \
-	                                YP_FMULTI, { check_modref } }, \
-	{ C_COMMENT,          YP_TSTR,  YP_VNONE },
+	{ C_FILE,                YP_TSTR,  YP_VNONE }, \
+	{ C_STORAGE,             YP_TSTR,  YP_VSTR = { STORAGE_DIR } }, \
+	{ C_MASTER,              YP_TREF,  YP_VREF = { C_RMT }, YP_FMULTI, { check_ref } }, \
+	{ C_DDNS_MASTER,         YP_TREF,  YP_VREF = { C_RMT }, YP_FNONE, { check_ref } }, \
+	{ C_NOTIFY,              YP_TREF,  YP_VREF = { C_RMT }, YP_FMULTI, { check_ref } }, \
+	{ C_ACL,                 YP_TREF,  YP_VREF = { C_ACL }, YP_FMULTI, { check_ref } }, \
+	{ C_SEM_CHECKS,          YP_TBOOL, YP_VNONE }, \
+	{ C_DISABLE_ANY,         YP_TBOOL, YP_VNONE }, \
+	{ C_ZONEFILE_SYNC,       YP_TINT,  YP_VINT = { -1, INT32_MAX, 0, YP_STIME } }, \
+	{ C_IXFR_DIFF,           YP_TBOOL, YP_VNONE }, \
+	{ C_MAX_JOURNAL_SIZE,    YP_TINT,  YP_VINT = { 0, INT64_MAX, INT64_MAX, YP_SSIZE } }, \
+	{ C_DNSSEC_SIGNING,      YP_TBOOL, YP_VNONE }, \
+	{ C_KASP_DB,             YP_TSTR,  YP_VSTR = { "keys" } }, \
+	{ C_SERIAL_POLICY,       YP_TOPT,  YP_VOPT = { serial_policies, SERIAL_POLICY_INCREMENT } }, \
+	{ C_REQUEST_EDNS_OPTION, YP_TDATA, YP_VDATA = { 0, NULL, edns_opt_to_bin, edns_opt_to_txt } }, \
+	{ C_MODULE,              YP_TDATA, YP_VDATA = { 0, NULL, mod_id_to_bin, mod_id_to_txt }, \
+	                                   YP_FMULTI, { check_modref } }, \
+	{ C_COMMENT,             YP_TSTR,  YP_VNONE },
 
 static const yp_item_t desc_template[] = {
 	{ C_ID, YP_TSTR, YP_VNONE },

src/knot/conf/scheme.h

@@ -61,6 +61,7 @@
 #define C_RATE_LIMIT		"\x0A""rate-limit"
 #define C_RATE_LIMIT_SLIP	"\x0F""rate-limit-slip"
 #define C_RATE_LIMIT_TBL_SIZE	"\x15""rate-limit-table-size"
+#define C_REQUEST_EDNS_OPTION	"\x13""request-edns-option"
 #define C_RMT			"\x06""remote"
 #define C_RUNDIR		"\x06""rundir"
 #define C_SECRET		"\x06""secret"

src/knot/conf/tools.c

@@ -31,6 +31,7 @@
 #include "knot/conf/confdb.h"
 #include "knot/conf/scheme.h"
 #include "libknot/errcode.h"
+#include "libknot/internal/utils.h"
 #include "libknot/yparser/yptrafo.h"
 
 static int hex_to_num(char hex) {
@@ -179,6 +180,74 @@ int mod_id_to_txt(
 	return KNOT_EOK;
 }
 
+int edns_opt_to_bin(
+	char const *txt,
+	size_t txt_len,
+	uint8_t *bin,
+	size_t *bin_len)
+{
+	char *suffix = NULL;
+	unsigned long number = strtoul(txt, &suffix, 10);
+
+	// Check for "code:[value]" format.
+	if (suffix <= txt || *suffix != ':' || number > UINT16_MAX) {
+		return KNOT_EINVAL;
+	}
+
+	// Store the option code.
+	uint16_t code = number;
+	if (*bin_len < sizeof(code)) {
+		return KNOT_ESPACE;
+	}
+	wire_write_u16(bin, code);
+	bin += sizeof(code);
+
+	// Prepare suffix input (behind colon character).
+	size_t txt_suffix_len = txt_len - (suffix - txt) - 1;
+	size_t bin_suffix_len = *bin_len - sizeof(code);
+	suffix++;
+
+	// Convert suffix data.
+	int ret = hex_text_to_bin(suffix, txt_suffix_len, bin, &bin_suffix_len);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	// Set output data length.
+	*bin_len = sizeof(code) + bin_suffix_len;
+
+	return KNOT_EOK;
+}
+
+int edns_opt_to_txt(
+	uint8_t const *bin,
+	size_t bin_len,
+	char *txt,
+	size_t *txt_len)
+{
+	uint16_t code = wire_read_u16(bin);
+
+	// Write option code part.
+	int code_len = snprintf(txt, *txt_len, "%u:", code);
+	if (code_len <= 0 || code_len >= *txt_len) {
+		return KNOT_ESPACE;
+	}
+
+	size_t data_len = *txt_len - code_len;
+
+	// Write possible option data part.
+	int ret = hex_text_to_txt(bin + sizeof(code), bin_len - sizeof(code),
+	                          txt + code_len, &data_len);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	// Set output text length.
+	*txt_len = code_len + data_len;
+
+	return KNOT_EOK;
+}
+
 int check_ref(
 	conf_check_t *args)
 {

src/knot/conf/tools.h

@@ -79,6 +79,20 @@ int mod_id_to_txt(
 	size_t *txt_len
 );
 
+int edns_opt_to_bin(
+	char const *txt,
+	size_t txt_len,
+	uint8_t *bin,
+	size_t *bin_len
+);
+
+int edns_opt_to_txt(
+	uint8_t const *bin,
+	size_t bin_len,
+	char *txt,
+	size_t *txt_len
+);
+
 int check_ref(
 	conf_check_t *args
 );

src/knot/zone/events/handlers.c

@@ -89,6 +89,44 @@ static knot_pkt_t *zone_query(const zone_t *zone, uint16_t pkt_type, mm_ctx_t *m
 	return pkt;
 }
 
+/*! \brief Set EDNS section. */
+static int prepare_edns(zone_t *zone, knot_pkt_t *pkt)
+{
+	conf_val_t opt = conf_zone_get(conf(), C_REQUEST_EDNS_OPTION, zone->name);
+
+	/* Check if an extra EDNS option is configured. */
+	conf_data(&opt);
+	if (opt.data == NULL) {
+		return KNOT_EOK;
+	}
+
+	knot_rrset_t opt_rr;
+	conf_val_t udp_max = conf_get(conf(), C_SRV, C_MAX_UDP_PAYLOAD);
+	int ret = knot_edns_init(&opt_rr, conf_int(&udp_max), 0,
+	                         KNOT_EDNS_VERSION, &pkt->mm);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	ret = knot_edns_add_option(&opt_rr, wire_read_u16(opt.data),
+	                           opt.len - sizeof(uint16_t),
+	                           opt.data + sizeof(uint16_t), &pkt->mm);
+	if (ret != KNOT_EOK) {
+		knot_rrset_clear(&opt_rr, &pkt->mm);
+		return ret;
+	}
+
+	knot_pkt_begin(pkt, KNOT_ADDITIONAL);
+
+	ret = knot_pkt_put(pkt, KNOT_COMPR_HINT_NONE, &opt_rr, KNOT_PF_FREE);
+	if (ret != KNOT_EOK) {
+		knot_rrset_clear(&opt_rr, &pkt->mm);
+		return ret;
+	}
+
+	return KNOT_EOK;
+}
+
 /*!
  * \brief Create a zone event query, send it, wait for the response and process it.
  *
@@ -119,6 +157,12 @@ static int zone_query_execute(zone_t *zone, uint16_t pkt_type, const conf_remote
 	knot_requestor_init(&re, &mm);
 	knot_requestor_overlay(&re, KNOT_STATE_ANSWER, &param);
 
+	/* Set EDNS section. */
+	ret = prepare_edns(zone, query);
+	if (ret != KNOT_EOK) {
+		goto fail;
+	}
+
 	const knot_tsig_key_t *key = remote->key.name != NULL ?
 	                             &remote->key : NULL;
 	tsig_init(&param.tsig_ctx, key);