1 files changed, 93 insertions, 0 deletions
diff --git a/src/knot/modules/queryacl/queryacl.c b/src/knot/modules/queryacl/queryacl.c
new file mode 100644
index 0000000..e787083
--- /dev/null
+++ b/src/knot/modules/queryacl/queryacl.c
@@ -0,0 +1,93 @@
+/*  Copyright (C) 2021 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
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "knot/include/module.h"
+#include "contrib/sockaddr.h"
+
+#define MOD_ADDRESS	"\x07""address"
+#define MOD_INTERFACE	"\x09""interface"
+
+const yp_item_t queryacl_conf[] = {
+	{ MOD_ADDRESS,   YP_TNET, YP_VNONE, YP_FMULTI },
+	{ MOD_INTERFACE, YP_TNET, YP_VNONE, YP_FMULTI },
+	{ NULL }
+};
+
+typedef struct {
+	knotd_conf_t allow_addr;
+	knotd_conf_t allow_iface;
+} queryacl_ctx_t;
+
+static knotd_state_t queryacl_process(knotd_state_t state, knot_pkt_t *pkt,
+                                      knotd_qdata_t *qdata, knotd_mod_t *mod)
+{
+	assert(pkt && qdata && mod);
+
+	queryacl_ctx_t *ctx = knotd_mod_ctx(mod);
+
+	// Continue only for regular queries.
+	if (qdata->type != KNOTD_QUERY_TYPE_NORMAL) {
+		return state;
+	}
+
+	if (ctx->allow_addr.count > 0) {
+		const struct sockaddr_storage *addr = knotd_qdata_remote_addr(qdata);
+		if (!knotd_conf_addr_range_match(&ctx->allow_addr, addr)) {
+			qdata->rcode = KNOT_RCODE_NOTAUTH;
+			return KNOTD_STATE_FAIL;
+		}
+	}
+
+	if (ctx->allow_iface.count > 0) {
+		struct sockaddr_storage buff;
+		const struct sockaddr_storage *addr = knotd_qdata_local_addr(qdata, &buff);
+		if (!knotd_conf_addr_range_match(&ctx->allow_iface, addr)) {
+			qdata->rcode = KNOT_RCODE_NOTAUTH;
+			return KNOTD_STATE_FAIL;
+		}
+	}
+
+	return state;
+}
+
+int queryacl_load(knotd_mod_t *mod)
+{
+	// Create module context.
+	queryacl_ctx_t *ctx = calloc(1, sizeof(queryacl_ctx_t));
+	if (ctx == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	ctx->allow_addr = knotd_conf_mod(mod, MOD_ADDRESS);
+	ctx->allow_iface = knotd_conf_mod(mod, MOD_INTERFACE);
+
+	knotd_mod_ctx_set(mod, ctx);
+
+	return knotd_mod_hook(mod, KNOTD_STAGE_BEGIN, queryacl_process);
+}
+
+void queryacl_unload(knotd_mod_t *mod)
+{
+	queryacl_ctx_t *ctx = knotd_mod_ctx(mod);
+	if (ctx != NULL) {
+		knotd_conf_free(&ctx->allow_addr);
+		knotd_conf_free(&ctx->allow_iface);
+	}
+	free(ctx);
+}
+
+KNOTD_MOD_API(queryacl, KNOTD_MOD_FLAG_SCOPE_ANY,
+              queryacl_load, queryacl_unload, queryacl_conf, NULL);