From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Mon, 20 Feb 2017 10:26:27 +0000 (+0100)
Subject: lua: add net.outgoing_{v4,v6} and documentation
X-Git-Tag: v1.3.0~23^2~70^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=09645444bd41462ef6cde19a276508f57eb36245;p=thirdparty%2Fknot-resolver.git

lua: add net.outgoing_{v4,v6} and documentation

Fixes https://gitlab.labs.nic.cz/knot/resolver/issues/158
The naming is inspired by Unbound's "outgoing-interface".
---

diff --git a/daemon/README.rst b/daemon/README.rst
index 8d62ab648..aa8990179 100644
--- a/daemon/README.rst
+++ b/daemon/README.rst
@@ -601,6 +601,11 @@ For when listening on ``localhost`` just doesn't cut it.
    have size of multiplies of 64 (64, 128, 192, ...).  Setting padding to
    value < 2 will disable it.
 
+.. function:: net.outgoing_v4([string address])
+
+   Get/set the IPv4 address used to perform queries.  There is also ``net.outgoing_v6`` for IPv6.
+   The default is ``nil``, which lets the OS choose any address.
+
 Trust anchors and DNSSEC
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/daemon/bindings.c b/daemon/bindings.c
index 26969087c..24f442753 100644
--- a/daemon/bindings.c
+++ b/daemon/bindings.c
@@ -21,6 +21,7 @@
 
 #include "lib/cache.h"
 #include "lib/cdb.h"
+#include "lib/utils.h"
 #include "daemon/bindings.h"
 #include "daemon/worker.h"
 #include "daemon/tls.h"
@@ -421,6 +422,63 @@ static int net_tls_padding(lua_State *L)
 	return 1;
 }
 
+static int net_outgoing(lua_State *L, int family)
+{
+	struct worker_ctx *worker = wrk_luaget(L);
+	union inaddr *addr;
+	if (family == AF_INET)
+		addr = (union inaddr*)&worker->out_addr4;
+	else
+		addr = (union inaddr*)&worker->out_addr6;
+
+	if (lua_gettop(L) == 0) { /* Return the current value. */
+		if (addr->ip.sa_family == AF_UNSPEC) {
+			lua_pushnil(L);
+			return 1;
+		}
+		if (addr->ip.sa_family != family) {
+			assert(false);
+			lua_error(L);
+		}
+		char addr_buf[INET6_ADDRSTRLEN];
+		int err;
+		if (family == AF_INET)
+			err = uv_ip4_name(&addr->ip4, addr_buf, sizeof(addr_buf));
+		else
+			err = uv_ip6_name(&addr->ip6, addr_buf, sizeof(addr_buf));
+		if (err)
+			lua_error(L);
+		lua_pushstring(L, addr_buf);
+		return 1;
+	}
+
+	if ((lua_gettop(L) != 1) || (!lua_isstring(L, 1) && !lua_isnil(L, 1))) {
+		format_error(L, "net.outgoing_vX takes one address string parameter or nil");
+		lua_error(L);
+	}
+
+	if (lua_isnil(L, 1)) {
+		addr->ip.sa_family = AF_UNSPEC;
+		return 1;
+	}
+
+	const char *addr_str = lua_tostring(L, 1);
+	int err;
+	if (family == AF_INET)
+		err = uv_ip4_addr(addr_str, 0, &addr->ip4);
+	else
+		err = uv_ip6_addr(addr_str, 0, &addr->ip6);
+	if (err) {
+		format_error(L, "net.outgoing_vX: failed to parse the address");
+		lua_error(L);
+	}
+	lua_pushboolean(L, true);
+	return 1;
+}
+
+static int net_outgoing_v4(lua_State *L) { return net_outgoing(L, AF_INET); }
+static int net_outgoing_v6(lua_State *L) { return net_outgoing(L, AF_INET6); }
+
 int lib_net(lua_State *L)
 {
 	static const luaL_Reg lib[] = {
@@ -432,6 +490,8 @@ int lib_net(lua_State *L)
 		{ "tcp_pipeline", net_pipeline },
 		{ "tls",          net_tls },
 		{ "tls_padding",  net_tls_padding },
+		{ "outgoing_v4",  net_outgoing_v4 },
+		{ "outgoing_v6",  net_outgoing_v6 },
 		{ NULL, NULL }
 	};
 	register_lib(L, "net", lib);