daemon/bindings: minimal Lua interface to packet and DNS primitives (wip)

daemon/bindings/kres.c

+/*  Copyright (C) 2015 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "daemon/bindings/kres.h"
+#include "daemon/bindings.h"
+
+/* Metatable list */
+#define META_PKT "kres.meta_pkt"
+
+/* 
+ * Packet interface
+ */
+
+#define WIRE_FLAGS(X) \
+	X(AA,aa) X(AD,ad) X(CD,cd) X(RD,rd) X(QR,qr) X(RA,ra) X(TC,tc)
+enum {
+	#define X(flag, _) WIRE_ ## flag,
+	WIRE_FLAGS(X)
+	#undef X
+};
+static lookup_table_t wire_flag_names[] = {
+	#define X(flag, _) { WIRE_ ## flag, #flag },
+	WIRE_FLAGS(X)
+	#undef X
+};
+
+static int pkt_flag(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	if (lua_gettop(L) > 1 && lua_isnumber(L, 2)) {
+		int flag_id = lua_tonumber(L, 2);
+		switch(flag_id) {
+		#define X(flag, code) case WIRE_ ## flag: knot_wire_set_ ## code (pkt->wire); break;
+		WIRE_FLAGS(X)
+		#undef X
+		}
+	}
+	return 0;
+}
+
+static int pkt_opcode(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	if (lua_gettop(L) > 1 && lua_isnumber(L, 2)) {
+		knot_wire_set_opcode(pkt->wire, lua_tonumber(L, 2));
+	}
+	lua_pushnumber(L, knot_wire_get_opcode(pkt->wire));
+	return 1;
+}
+
+static int pkt_rcode(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	if (lua_gettop(L) > 1 && lua_isnumber(L, 2)) {
+		knot_wire_set_rcode(pkt->wire, lua_tonumber(L, 2));
+	}
+	lua_pushnumber(L, knot_wire_get_rcode(pkt->wire));
+	return 1;
+}
+
+static int pkt_qtype(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	lua_pushnumber(L, knot_pkt_qtype(pkt));
+	return 1;
+}
+
+static int pkt_qclass(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	lua_pushnumber(L, knot_pkt_qclass(pkt));
+	return 1;	
+}
+
+static int pkt_qname(lua_State *L)
+{
+	knot_pkt_t *pkt = luaL_checkudata(L, 1, META_PKT);
+	const knot_dname_t *dname = knot_pkt_qname(pkt);
+	char dname_str[KNOT_DNAME_MAXLEN];
+	knot_dname_to_str(dname_str, dname, sizeof(dname_str));
+	lua_pushstring(L, dname_str);
+	return 1;	
+}
+
+#warning TODO: record interfaces
+
+static int pkt_meta_set(lua_State *L)
+{
+	static const luaL_Reg pkt_wrap[] = {
+		{ "flag",      pkt_flag},
+		{ "rcode",     pkt_rcode},
+		{ "opcode",    pkt_opcode},
+		{ "qtype",     pkt_qtype },
+		{ "qclass",    pkt_qclass },
+		{ "qname",     pkt_qname },
+		{ NULL, NULL }
+	};
+	luaL_newmetatable(L, META_PKT);
+	luaL_setfuncs(L, pkt_wrap, 0);
+	lua_pushvalue(L, -1);
+	lua_setfield(L, -2, "__index");
+	lua_pop(L, 1);
+	return 0;
+}
+
+static int pkt_meta_get(lua_State *L)
+{
+	luaL_getmetatable(L, META_PKT);
+	lua_setmetatable(L, -2);
+	return 1;
+}
+
+/**
+ * Resolution context interface.
+ */
+
+#warning TODO: context interface, rplan
+
+#define WRAP_NUMBER(L, name, val) \
+	lua_pushnumber((L), (val)); \
+	lua_setfield((L), -2, (name))
+
+#define WRAP_CONST(L, name, prefix...) \
+	WRAP_NUMBER(L, #name, prefix ## name)
+
+#define WRAP_LUT(L, prefix, table) \
+	lua_newtable(L); \
+	for (lookup_table_t *elm = (table); elm->name; ++elm) { \
+		WRAP_NUMBER((L), elm->name, elm->id); \
+	} \
+	lua_setfield((L), -2, (prefix))
+
+int lib_kres(lua_State *L)
+{
+	static const luaL_Reg lib[] = {
+		{ "packet", pkt_meta_get },
+		{ NULL, NULL }
+	};
+	/* Create module and register functions */
+	register_lib(L, "kres", lib);
+	/* Register states */
+	WRAP_CONST(L, NOOP,    KNOT_STATE_);
+	WRAP_CONST(L, CONSUME, KNOT_STATE_);
+	WRAP_CONST(L, PRODUCE, KNOT_STATE_);
+	WRAP_CONST(L, DONE,    KNOT_STATE_);
+	WRAP_CONST(L, FAIL,    KNOT_STATE_);
+	/* Register RCODE, OPCODE */
+	WRAP_LUT(L, "rcode",  knot_rcode_names);
+	WRAP_LUT(L, "opcode", knot_opcode_names);
+	WRAP_LUT(L, "wire",   wire_flag_names);
+	/* Register metatables */
+	pkt_meta_set(L);
+	return 1;	
+}
\ No newline at end of file

daemon/bindings/kres.h

+/*  Copyright (C) 2015 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 <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Lua-friendly bindings to resolver library parts,
+ * notably packet parsing and interpretation and operation on primitives like domain names.
+ */
+#pragma once
+
+#include "daemon/bindings.h"
+
+/**
+ * Load libkres library.
+ * @param  L scriptable
+ * @return   number of packages to load
+ */
+int lib_kres(lua_State *L);
\ No newline at end of file

daemon/main.c

@@ -27,6 +27,7 @@
 #include "daemon/worker.h"
 #include "daemon/engine.h"
 #include "daemon/bindings.h"
+#include "daemon/bindings/kres.h"
 
 static void tty_read(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf)
 {
@@ -145,6 +146,7 @@ int main(int argc, char **argv)
 	engine_lualib(&engine, "net",     lib_net);
 	engine_lualib(&engine, "cache",   lib_cache);
 	engine_lualib(&engine, "event",   lib_event);
+	engine_lualib(&engine, "kres",    lib_kres);
 
 	/* Create main worker. */
 	struct worker_ctx *worker = mm_alloc(&pool, sizeof(*worker));