From: Marek Vavruša <mvavrusa@cloudflare.com>
Date: Fri, 6 Apr 2018 05:48:51 +0000 (-0700)
Subject: add bindings for the checkout layer
X-Git-Tag: v2.4.0~53^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=98c8d35364b90a8bf2f3705526c68931917152b6;p=thirdparty%2Fknot-resolver.git

add bindings for the checkout layer

This one was missing from the current bindings. The checkout layer
runs when the worker attempts to send a DNS query to given upstream
when the address is already determined. The layer can add EDNS options
or update outbound query, or block particular addresses / protocol.
---

diff --git a/daemon/ffimodule.c b/daemon/ffimodule.c
index 3fb37bee9..496867d70 100644
--- a/daemon/ffimodule.c
+++ b/daemon/ffimodule.c
@@ -36,6 +36,7 @@ enum {
 	SLOT_finish,
 	SLOT_consume,
 	SLOT_produce,
+	SLOT_checkout,
 	SLOT_count
 };
 #define SLOT_size sizeof(int)
@@ -127,6 +128,7 @@ static int l_ffi_deinit(struct kr_module *module)
 		LAYER_UNREGISTER(L, api, finish);
 		LAYER_UNREGISTER(L, api, consume);
 		LAYER_UNREGISTER(L, api, produce);
+		LAYER_UNREGISTER(L, api, checkout);
 		LAYER_UNREGISTER(L, api, reset);
 		free(api);
 	}
@@ -190,6 +192,19 @@ static int l_ffi_layer_produce(kr_layer_t *ctx, knot_pkt_t *pkt)
 	lua_pushlightuserdata(L, pkt);
 	return l_ffi_call(L, 3);
 }
+
+static int l_ffi_layer_checkout(kr_layer_t *ctx, knot_pkt_t *pkt, struct sockaddr *dst, int type)
+{
+	if (ctx->state & (KR_STATE_FAIL)) {
+		return ctx->state; /* Already failed or done, skip */
+	}
+	LAYER_FFI_CALL(ctx, checkout);
+	lua_pushlightuserdata(L, ctx->req);
+	lua_pushlightuserdata(L, pkt);
+	lua_pushlightuserdata(L, dst);
+	lua_pushboolean(L, type == SOCK_STREAM);
+	return l_ffi_call(L, 5);
+}
 #undef LAYER_FFI_CALL
 
 /** @internal Conditionally register layer trampoline
@@ -218,6 +233,7 @@ static kr_layer_api_t *l_ffi_layer_create(lua_State *L, struct kr_module *module
 		LAYER_REGISTER(L, api, finish);
 		LAYER_REGISTER(L, api, consume);
 		LAYER_REGISTER(L, api, produce);
+		LAYER_REGISTER(L, api, checkout);
 		LAYER_REGISTER(L, api, reset);
 		/* Begin is always set, as it initializes layer baton. */
 		api->begin = l_ffi_layer_begin;
diff --git a/lib/layer.h b/lib/layer.h
index 2d2e86cda..227ff99aa 100644
--- a/lib/layer.h
+++ b/lib/layer.h
@@ -78,6 +78,11 @@ struct kr_layer_api {
 	/** Produce either an answer to the request or a query for upstream (or fail). */
 	int (*produce)(kr_layer_t *ctx, knot_pkt_t *pkt);
 
+	/** Finalises the outbound query packet with the knowledge of the IP addresses.
+	 * The checkout layer doesn't persist the state, so canceled subrequests
+	 * don't affect the resolution or rest of the processing. */
+	int (*checkout)(kr_layer_t *ctx, knot_pkt_t *packet, struct sockaddr *dst, int type);
+
 	/** The module can store anything in here. */
 	void *data;
 };
diff --git a/lib/module.h b/lib/module.h
index 945283ccc..74acf6015 100644
--- a/lib/module.h
+++ b/lib/module.h
@@ -35,7 +35,7 @@ struct kr_prop;
  */
 #define KR_MODULE_EXPORT(module) \
     KR_EXPORT uint32_t module ## _api() { return KR_MODULE_API; }
-#define KR_MODULE_API ((uint32_t) 0x20161108)
+#define KR_MODULE_API ((uint32_t) 0x20180401)
 
 typedef uint32_t (module_api_cb)(void);
 
diff --git a/lib/resolve.c b/lib/resolve.c
index f7b313869..eed3fd902 100644
--- a/lib/resolve.c
+++ b/lib/resolve.c
@@ -94,6 +94,7 @@ static int begin_yield(kr_layer_t *ctx) { return kr_ok(); }
 static int reset_yield(kr_layer_t *ctx) { return kr_ok(); }
 static int finish_yield(kr_layer_t *ctx) { return kr_ok(); }
 static int produce_yield(kr_layer_t *ctx, knot_pkt_t *pkt) { return kr_ok(); }
+static int checkout_yield(kr_layer_t *ctx, knot_pkt_t *packet, struct sockaddr *dst, int type) { return kr_ok(); }
 
 /** @internal Macro for iterating module layers. */
 #define RESUME_LAYERS(from, r, qry, func, ...) \
@@ -1532,6 +1533,14 @@ int kr_resolve_checkout(struct kr_request *request, struct sockaddr *src,
 	}
 	struct kr_query *qry = array_tail(rplan->pending);
 
+	/* Run the checkout layers and cancel on failure. */
+	int state = request->state;
+	ITERATE_LAYERS(request, qry, checkout, packet, dst, type);
+	if (request->state == KR_STATE_FAIL) {
+		request->state = state; /* Restore */
+		return kr_error(ECANCELED);
+	}
+
 #if defined(ENABLE_COOKIES)
 	/* Update DNS cookies in request. */
 	if (type == SOCK_DGRAM) { /* @todo: Add cookies also over TCP? */