From df5e2ce05ba783660a460b148e0bd0f8757dda95 Mon Sep 17 00:00:00 2001
From: nvx <neovortex@gmail.com>
Date: Sat, 2 Nov 2024 19:53:23 +1000
Subject: [PATCH] improve cardhopper to improve reliability when parts of the
 packet are buffered

---
 armsrc/Standalone/hf_cardhopper.c | 28 ++++++++++++++++++++++------
 common_arm/usb_cdc.c              |  4 ++++
 common_arm/usb_cdc.h              |  1 +
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/armsrc/Standalone/hf_cardhopper.c b/armsrc/Standalone/hf_cardhopper.c
index f1aef76e6..bf31e061a 100644
--- a/armsrc/Standalone/hf_cardhopper.c
+++ b/armsrc/Standalone/hf_cardhopper.c
@@ -33,7 +33,10 @@
 #ifdef CARDHOPPER_USB
 #define cardhopper_write usb_write
 #define cardhopper_read usb_read_ng
-#define cardhopper_data_available usb_poll_validate_length
+bool cardhopper_data_available(void);
+bool cardhopper_data_available(void) {
+    return usb_read_ng_has_buffered_data() || usb_poll_validate_length();
+}
 #else
 #define cardhopper_write usart_writebuffer_sync
 #define cardhopper_read usart_read_ng
@@ -107,14 +110,22 @@ void RunMod(void) {
             break;
         }
 
-        if (memcmp(magicREAD, modeRx.dat, sizeof(magicREAD)) == 0) {
+        if (modeRx.len == 0) {
+            DbpString(_CYAN_("[@]") " Zero length message");
+            continue;
+        }
+
+        if (modeRx.len == sizeof(magicREAD) && memcmp(magicREAD, modeRx.dat, sizeof(magicREAD)) == 0) {
             DbpString(_CYAN_("[@]") " I am a READER. I talk to a CARD.");
             become_reader();
-        } else if (memcmp(magicCARD, modeRx.dat, sizeof(magicCARD)) == 0) {
+        } else if (modeRx.len == sizeof(magicCARD) && memcmp(magicCARD, modeRx.dat, sizeof(magicCARD)) == 0) {
             DbpString(_CYAN_("[@]") " I am a CARD. I talk to a READER.");
             become_card();
-        } else if (memcmp(magicEND, modeRx.dat, sizeof(magicEND)) == 0) {
+        } else if (modeRx.len == sizeof(magicEND) && memcmp(magicEND, modeRx.dat, sizeof(magicEND)) == 0) {
             break;
+        } else if (modeRx.len == sizeof(magicRSRT) && memcmp(magicRSRT, modeRx.dat, sizeof(magicRSRT)) == 0) {
+            DbpString(_CYAN_("[@]") " Got RESET but already reset.");
+            continue;
         } else {
             DbpString(_YELLOW_("[!]") " unknown mode!");
             Dbhexdump(modeRx.len, modeRx.dat, true);
@@ -142,7 +153,12 @@ static void become_reader(void) {
         WDT_HIT();
 
         read_packet(rx);
-        if (memcmp(magicRSRT, rx->dat, sizeof(magicRSRT)) == 0) break;
+        if (rx->len == sizeof(magicRSRT) && memcmp(magicRSRT, rx->dat, sizeof(magicRSRT)) == 0) break;
+
+        if (BUTTON_PRESS()) {
+            DbpString(_CYAN_("[@]") " Button pressed - Breaking from reader loop");
+            break;
+        }
 
         if (rx->dat[0] == ISO14443A_CMD_RATS && rx->len == 4) {
             // got RATS from reader, reset the card
@@ -206,7 +222,7 @@ static void become_card(void) {
     iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
     uint8_t tagType;
-    uint16_t flags;
+    uint16_t flags = 0;
     uint8_t data[PM3_CMD_DATA_SIZE] = { 0 };
     packet_t ats = { 0 };
     prepare_emulation(&tagType, &flags, data, &ats);
diff --git a/common_arm/usb_cdc.c b/common_arm/usb_cdc.c
index 2447330c8..a72cb4a32 100644
--- a/common_arm/usb_cdc.c
+++ b/common_arm/usb_cdc.c
@@ -718,6 +718,10 @@ static uint8_t usb_read_ng_buffer[64] = {0};
 static uint8_t usb_read_ng_bufoffset = 0;
 static uint8_t usb_read_ng_buflen = 0;
 
+bool usb_read_ng_has_buffered_data(void) {
+    return usb_read_ng_buflen > 0;
+}
+
 uint32_t usb_read_ng(uint8_t *data, size_t len) {
 
     if (len == 0) {
diff --git a/common_arm/usb_cdc.h b/common_arm/usb_cdc.h
index 9c7cb7299..2df1acc1e 100644
--- a/common_arm/usb_cdc.h
+++ b/common_arm/usb_cdc.h
@@ -39,6 +39,7 @@ int async_usb_write_start(void);
 void async_usb_write_pushByte(uint8_t data);
 bool async_usb_write_requestWrite(void);
 int async_usb_write_stop(void);
+bool usb_read_ng_has_buffered_data(void);
 uint32_t usb_read_ng(uint8_t *data, size_t len);
 void usb_update_serial(uint64_t newSerialNumber);