From dba677681782f9475fcf09a72d19696e083a81d3 Mon Sep 17 00:00:00 2001
From: StapleButter <thetotalworm@gmail.com>
Date: Fri, 12 May 2017 01:21:39 +0200
Subject: more work on packet reception.

---
 src/Wifi.cpp        | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 src/wx/Platform.cpp |  5 ++--
 src/wx/main.cpp     |  2 ++
 3 files changed, 71 insertions(+), 5 deletions(-)

diff --git a/src/Wifi.cpp b/src/Wifi.cpp
index fa056ca..6553a8d 100644
--- a/src/Wifi.cpp
+++ b/src/Wifi.cpp
@@ -60,9 +60,12 @@ typedef struct
 
 TXSlot TXSlots[6];
 
+u8 RXBuffer[2048];
+
 bool MPInited;
 
 
+
 // multiplayer host TX sequence:
 // 1. preamble
 // 2. IRQ7
@@ -197,7 +200,7 @@ void SetIRQ14(bool forced)
 
     if (IOPORT(W_TXSlotBeacon) & 0x8000)
     {
-        //StartTX_Beacon();
+        StartTX_Beacon();
     }
 
     if (IOPORT(W_ListenCount) == 0)
@@ -218,6 +221,12 @@ void SetIRQ15()
 }
 
 
+bool MACEqual(u8* a, u8* b)
+{
+    return (*(u32*)&a[0] == *(u32*)&b[0]) && (*(u16*)&a[4] == *(u16*)&b[4]);
+}
+
+
 // TODO: set RFSTATUS/RFPINS
 
 int PreambleLen(int rate)
@@ -246,7 +255,8 @@ void StartTX_Beacon()
     u64 oldval = *(u64*)&RAM[slot->Addr + 0xC + 24];
     *(u64*)&RAM[slot->Addr + 0xC + 24] = USCounter;
 
-    Platform::MP_SendPacket(&RAM[slot->Addr], 12 + slot->Length);
+    int txlen = Platform::MP_SendPacket(&RAM[slot->Addr], 12 + slot->Length);
+    printf("wifi: sent %d/%d bytes of packet\n", txlen, 12+slot->Length);
 
     *(u64*)&RAM[slot->Addr + 0xC + 24] = oldval;
 }
@@ -287,6 +297,57 @@ void ProcessTX(TXSlot* slot, int busybit)
 }
 
 
+void CheckRX()
+{
+    int rxlen = Platform::MP_RecvPacket(RXBuffer, false);
+    if (rxlen < 12+24) return;
+
+    u16 framectl = *(u16*)&RXBuffer[12+0];
+
+    u32 a_src, a_dst, a_bss;
+    switch (framectl & 0x000C)
+    {
+    case 0x0000: // management:
+        a_src = 10;
+        a_dst = 4;
+        a_bss = 16;
+        break;
+
+    case 0x0004: // control
+        printf("blarg\n");
+        return;
+
+    case 0x0008: // data
+        switch (framectl & 0x0300)
+        {
+        case 0x0000: // STA to STA
+            a_src = 10;
+            a_dst = 4;
+            a_bss = 16;
+            break;
+        case 0x0100: // STA to DS
+            a_src = 10;
+            a_dst = 16;
+            a_bss = 4;
+            break;
+        case 0x0200: // DS to STA
+            a_src = 16;
+            a_dst = 4;
+            a_bss = 10;
+            break;
+        case 0x0300: // DS to DS
+            printf("blarg\n");
+            return;
+        }
+    }
+
+    if (MACEqual(&RXBuffer[12 + a_src], (u8*)&IOPORT(W_MACAddr0)))
+        return; // oops. we received a packet we just sent.
+
+    printf("wifi: received packet. framectrl=%04X\n", framectl);
+}
+
+
 void MSTimer()
 {
     IOPORT(W_BeaconCount1)--;
@@ -300,6 +361,8 @@ void MSTimer()
         IOPORT(W_BeaconCount2)--;
         if (IOPORT(W_BeaconCount2) == 0) SetIRQ13();
     }
+
+    CheckRX();
 }
 
 void USTimer(u32 param)
@@ -380,7 +443,7 @@ u16 Read(u32 addr)
         return *(u16*)&RAM[addr & 0x1FFE];
     }
     if (addr >= 0x2000 && addr < 0x4000)
-        return 0xFFFF; // checkme
+        return 0xFFFF;
 
     bool activeread = (addr < 0x1000);
 
diff --git a/src/wx/Platform.cpp b/src/wx/Platform.cpp
index 12145f3..95da1bc 100644
--- a/src/wx/Platform.cpp
+++ b/src/wx/Platform.cpp
@@ -134,7 +134,9 @@ int MP_SendPacket(u8* data, int len)
     *(u16*)&PacketBuffer[6] = htons(len);
     memcpy(&PacketBuffer[8], data, len);
 
-    return sendto(MPSocket, (const char*)PacketBuffer, len+8, 0, &MPSendAddr, sizeof(sockaddr_t));
+    int slen = sendto(MPSocket, (const char*)PacketBuffer, len+8, 0, &MPSendAddr, sizeof(sockaddr_t));
+    if (slen < 8) return 0;
+    return slen - 8;
 }
 
 int MP_RecvPacket(u8* data, bool block)
@@ -174,7 +176,6 @@ int MP_RecvPacket(u8* data, bool block)
         return 0;
     }
 
-    rlen -= 8;
     if (ntohs(*(u16*)&PacketBuffer[6]) != rlen)
     {
         return 0;
diff --git a/src/wx/main.cpp b/src/wx/main.cpp
index 214996a..576a81d 100644
--- a/src/wx/main.cpp
+++ b/src/wx/main.cpp
@@ -33,6 +33,8 @@ wxIMPLEMENT_APP_NO_MAIN(wxApp_melonDS);
 
 int main(int argc, char** argv)
 {
+    srand(time(NULL));
+
     // http://stackoverflow.com/questions/14543333/joystick-wont-work-using-sdl
     SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");
 
-- 
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