From: Tomas Krizek <tomas.krizek@nic.cz>
Date: Wed, 27 Oct 2021 14:32:18 +0000 (+0200)
Subject: modules/extended_error: OPT section modification
X-Git-Tag: v5.5.0~26^2~16
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=abe02f8f2eedc4aa677a45ee89c543f384a775c1;p=thirdparty%2Fknot-resolver.git

modules/extended_error: OPT section modification
---

diff --git a/daemon/lua/sandbox.lua.in b/daemon/lua/sandbox.lua.in
index f71ed3586..7c6a818bb 100644
--- a/daemon/lua/sandbox.lua.in
+++ b/daemon/lua/sandbox.lua.in
@@ -509,6 +509,7 @@ modules.load('ta_sentinel')
 modules.load('edns_keepalive')
 modules.load('refuse_nord')
 modules.load('watchdog')
+modules.load('extended_error')
 
 -- Load keyfile_default
 trust_anchors.add_file('@keyfile_default@', @unmanaged@)
diff --git a/daemon/worker.c b/daemon/worker.c
index 73a1900f9..c8bceffd1 100644
--- a/daemon/worker.c
+++ b/daemon/worker.c
@@ -391,6 +391,7 @@ static struct request_ctx *request_create(struct worker_ctx *worker,
 	req->vars_ref = LUA_NOREF;
 	req->uid = uid;
 	req->qsource.flags.xdp = is_xdp;
+	kr_request_set_extended_error(req, KNOT_EDNS_EDE_NONE, NULL);
 	array_init(req->qsource.headers);
 	if (session) {
 		req->qsource.flags.tcp = session_get_handle(session)->type == UV_TCP;
diff --git a/lib/defines.h b/lib/defines.h
index 618903f46..226f7216f 100644
--- a/lib/defines.h
+++ b/lib/defines.h
@@ -8,6 +8,7 @@
 #include <libknot/errcode.h>
 #include <libknot/dname.h>
 #include <libknot/rrset.h>
+#include <libknot/version.h>
 
 /* Function attributes */
 #if __GNUC__ >= 4
@@ -70,6 +71,11 @@ static inline int KR_COLD kr_error(int x) {
 #define KR_DNAME_STR_MAXLEN (KNOT_DNAME_TXT_MAXLEN + 1)
 #define KR_RRTYPE_STR_MAXLEN (16 + 1)
 
+/* Compatibility with libknot<3.1.0 */
+#if KNOT_VERSION_HEX < 0x030100
+#define KNOT_EDNS_EDE_NONE (-1)
+#endif
+
 /*
  * Address sanitizer hints.
  */
diff --git a/modules/extended_error/extended_error.c b/modules/extended_error/extended_error.c
new file mode 100644
index 000000000..db0ed577d
--- /dev/null
+++ b/modules/extended_error/extended_error.c
@@ -0,0 +1,47 @@
+#include <libknot/rrtype/opt.h>
+
+#include "lib/module.h"
+#include "daemon/engine.h"
+
+static int extended_error_finalize(kr_layer_t *ctx) {
+	struct kr_request *req = ctx->req;
+	const knot_rrset_t *src_opt = req->qsource.packet->opt_rr;
+	const struct kr_extended_error *ede = &req->extended_error;
+
+	if (ede->info_code == KNOT_EDNS_EDE_NONE  /* no extended error */
+	    || src_opt == NULL  /* no EDNS in query */
+	    || kr_fails_assert(ede->info_code >= 0 && ede->info_code < UINT16_MAX)  /* info code out of range */
+	    || kr_fails_assert(req->answer->opt_rr)  /* sanity check - answer should have EDNS */
+	    ) {
+		return ctx->state;
+	}
+
+	const uint16_t info_code = (uint16_t)ede->info_code;
+	const size_t extra_len = ede->extra_text ? strlen(ede->extra_text) : 0;
+	uint8_t buf[sizeof(info_code) + extra_len];
+	knot_wire_write_u16(buf, info_code);
+	if (extra_len)
+		memcpy(buf + sizeof(info_code), ede->extra_text, extra_len);
+
+	if (knot_edns_add_option(req->answer->opt_rr, KNOT_EDNS_OPTION_EDE,
+				 sizeof(buf), buf, &req->pool) != KNOT_EOK) {
+		/* something went wrong and there is no way to salvage content of OPT RRset */
+		kr_log_req(req, 0, 0, EDE, "unable to add Extended Error option\n");
+		knot_rrset_clear(req->answer->opt_rr, &req->pool);
+	}
+
+	return ctx->state;
+}
+
+KR_EXPORT
+int extended_error_init(struct kr_module *module) {
+	static kr_layer_api_t layer = {
+		.answer_finalize = &extended_error_finalize,
+	};
+	layer.data = module;
+	module->layer = &layer;
+
+	return kr_ok();
+}
+
+KR_MODULE_EXPORT(extended_error)
diff --git a/modules/extended_error/meson.build b/modules/extended_error/meson.build
new file mode 100644
index 000000000..26e87b0c6
--- /dev/null
+++ b/modules/extended_error/meson.build
@@ -0,0 +1,20 @@
+# C module: extended_error
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+extended_error_src = files([
+  'extended_error.c',
+])
+c_src_lint += extended_error_src
+
+extended_error_mod = shared_module(
+  'extended_error',
+  extended_error_src,
+  dependencies: [
+    libknot,
+    luajit_inc,
+  ],
+  include_directories: mod_inc_dir,
+  name_prefix: '',
+  install: true,
+  install_dir: modules_dir,
+)
diff --git a/modules/meson.build b/modules/meson.build
index cf03859b3..6ac4f8bd9 100644
--- a/modules/meson.build
+++ b/modules/meson.build
@@ -42,6 +42,7 @@ subdir('daf')
 subdir('dnstap')
 subdir('edns_keepalive')
 subdir('experimental_dot_auth')
+subdir('extended_error')
 subdir('hints')
 subdir('http')
 subdir('nsid')