dns: implement GetHostByName redirection (backend TODO)

stratosphere/ams_mitm/source/dns_mitm/sfdnsres_shim.c

@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 "sfdnsres_shim.h"
+#include <stratosphere/sf/sf_mitm_dispatch.h>
+
+/* Command forwarders. */
+Result sfdnsresGetHostByNameRequestWithOptionsFwd(Service *s, u64 process_id, const void *name, size_t name_size, void *out_hostent, size_t out_hostent_size, u32 *out_size, u32 options_version, const void *option, size_t option_size, u32 num_options, s32 *out_host_error, s32 *out_errno) {
+    const struct {
+        u32 options_version;
+        u32 num_options;
+        u64 process_id;
+    } in = { options_version, num_options, process_id };
+    struct {
+        u32 size;
+        s32 host_error;
+        s32 errno;
+    } out;
+
+    Result rc = serviceMitmDispatchInOut(s, 10, in, out,
+        .buffer_attrs = {
+            SfBufferAttr_HipcAutoSelect | SfBufferAttr_In,
+            SfBufferAttr_HipcAutoSelect | SfBufferAttr_Out,
+            SfBufferAttr_HipcAutoSelect | SfBufferAttr_In
+        },
+        .buffers = {
+            { name, name_size },
+            { out_hostent, out_hostent_size },
+            { option, option_size }
+        },
+        .in_send_pid = true,
+        .override_pid = process_id,
+    );
+
+    if (R_SUCCEEDED(rc)) {
+        if (out_size) *out_size = out.size;
+        if (out_host_error) *out_host_error = out.host_error;
+        if (out_errno) *out_errno = out.errno;
+    }
+
+    return rc;
+}