From a09843cbd632e947b6842130d2cf5caeae283769 Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Sat, 19 Oct 2019 15:48:54 -0400
Subject: [PATCH] iccard/felica.c: Add initial FeliCa IC emulator

---
 iccard/felica.c    | 192 +++++++++++++++++++++++++++++++++++++++++++++
 iccard/felica.h    |  27 +++++++
 iccard/meson.build |   2 +
 3 files changed, 221 insertions(+)
 create mode 100644 iccard/felica.c
 create mode 100644 iccard/felica.h

diff --git a/iccard/felica.c b/iccard/felica.c
new file mode 100644
index 0000000..ba71232
--- /dev/null
+++ b/iccard/felica.c
@@ -0,0 +1,192 @@
+#include <windows.h>
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "hook/iobuf.h"
+
+#include "iccard/felica.h"
+
+#include "util/dprintf.h"
+#include "util/dump.h"
+
+static HRESULT felica_cmd_poll(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res);
+
+static HRESULT felica_cmd_get_system_code(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res);
+
+static HRESULT felica_cmd_nda_a4(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res);
+
+uint64_t felica_get_generic_PMm(void)
+{
+    /* A FeliCa PMm contains low-level protocol timing information for
+       communicating with a particular IC card. The exact values are not
+       particularly important for our purposes, so we'll just return a hard-
+       coded PMm. This was taken from a SuiCa train pass I bought in Japan. */
+
+    return 0x053143454682B7FFULL;
+}
+
+HRESULT felica_transact(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res)
+{
+    uint64_t IDm;
+    uint8_t code;
+    HRESULT hr;
+
+    assert(f != NULL);
+    assert(req != NULL);
+    assert(res != NULL);
+
+    hr = iobuf_read_8(req, &code);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = iobuf_write_8(res, code + 1);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    if (code != FELICA_CMD_POLL) {
+        hr = iobuf_read_be64(req, &IDm);
+
+        if (FAILED(hr)) {
+            return hr;
+        }
+
+        if (IDm != f->IDm) {
+            return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
+        }
+
+        hr = iobuf_write_be64(res, IDm);
+
+        if (FAILED(hr)) {
+            return hr;
+        }
+    }
+
+    switch (code) {
+    case FELICA_CMD_POLL:
+        return felica_cmd_poll(f, req, res);
+
+    case FELICA_CMD_GET_SYSTEM_CODE:
+        return felica_cmd_get_system_code(f, req, res);
+
+    case FELICA_CMD_NDA_A4:
+        return felica_cmd_nda_a4(f, req, res);
+
+    default:
+        dprintf("FeliCa: Unimplemented command %02x, payload:\n", code);
+        dump_const_iobuf(req);
+
+        return E_NOTIMPL;
+    }
+}
+
+static HRESULT felica_cmd_poll(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res)
+{
+    uint16_t system_code;
+    uint8_t request_code;
+    uint8_t time_slot;
+    HRESULT hr;
+
+    /* Request: */
+
+    hr = iobuf_read_be16(req, &system_code);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = iobuf_read_8(req, &request_code);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = iobuf_read_8(req, &time_slot);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    if (system_code != 0xFFFF && system_code != f->system_code) {
+        return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
+    }
+
+    // TODO handle other params correctly...
+
+    /* Response: */
+
+    hr = iobuf_write_be64(res, f->IDm);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = iobuf_write_be64(res, f->PMm);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    if (request_code == 0x01) {
+        hr = iobuf_write_be16(res, f->system_code);
+
+        if (FAILED(hr)) {
+            return hr;
+        }
+    }
+
+    return S_OK;
+}
+
+static HRESULT felica_cmd_get_system_code(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res)
+{
+    HRESULT hr;
+
+    hr = iobuf_write_8(res, 1); /* Number of system codes */
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = iobuf_write_be16(res, f->system_code);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    return S_OK;
+}
+
+static HRESULT felica_cmd_nda_a4(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res)
+{
+    /* The specification for this command is probably only available under NDA.
+       Returning what the driver seems to want. */
+
+    return iobuf_write_8(res, 0);
+}
diff --git a/iccard/felica.h b/iccard/felica.h
new file mode 100644
index 0000000..33be201
--- /dev/null
+++ b/iccard/felica.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <windows.h>
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "hook/iobuf.h"
+
+enum {
+    FELICA_CMD_POLL             = 0x00,
+    FELICA_CMD_GET_SYSTEM_CODE  = 0x0c,
+    FELICA_CMD_NDA_A4           = 0xa4,
+};
+
+struct felica {
+    uint64_t IDm;
+    uint64_t PMm;
+    uint16_t system_code;
+};
+
+HRESULT felica_transact(
+        struct felica *f,
+        struct const_iobuf *req,
+        struct iobuf *res);
+
+uint64_t felica_get_generic_PMm(void);
diff --git a/iccard/meson.build b/iccard/meson.build
index c01d505..1da0d1e 100644
--- a/iccard/meson.build
+++ b/iccard/meson.build
@@ -7,5 +7,7 @@ iccard_lib = static_library(
         capnhook.get_variable('hook_dep'),
     ],
     sources : [
+        'felica.c',
+        'felica.h',
     ],
 )