start working on melonAP.

it sends beacons!

src/WifiAP.cpp

@@ -18,6 +18,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include "NDS.h"
 #include "Wifi.h"
 #include "WifiAP.h"
 
@@ -25,6 +26,137 @@
 namespace WifiAP
 {
 
-//
+#define AP_MAC  0x00, 0xF0, 0x77, 0x77, 0x77, 0x77
+#define AP_NAME "melonAP"
+
+const u8 APMac[6] = {AP_MAC};
+
+#define PWRITE_8(p, v)      *p++ = v;
+#define PWRITE_16(p, v)     *(u16*)p = v; p += 2;
+#define PWRITE_32(p, v)     *(u32*)p = v; p += 4;
+#define PWRITE_64(p, v)     *(u64*)p = v; p += 8;
+
+#define PWRITE_MAC(p, a,b,c,d,e,f) \
+    *p++ = a; *p++ = b; *p++ = c; *p++ = d; *p++ = e; *p++ = f;
+
+#define PWRITE_MAC2(p, m) \
+    *p++ = m[0]; *p++ = m[1]; *p++ = m[2]; *p++ = m[3]; *p++ = m[4]; *p++ = m[5];
+
+#define PWRITE_SEQNO(p)     PWRITE_16(p, SeqNo); SeqNo += 0x10;
+
+#define PWRITE_TXH(p, len, rate) \
+    PWRITE_16(p, 0); \
+    PWRITE_16(p, 0); \
+    PWRITE_16(p, 0); \
+    PWRITE_16(p, 0); \
+    PWRITE_8(p, rate); \
+    PWRITE_8(p, 0); \
+    PWRITE_16(p, len);
+
+//#define PALIGN_4(p, base)  p += ((4 - ((ptrdiff_t)(p-base) & 0x3)) & 0x3);
+// no idea what is the ideal padding there
+// but in the case of management frames the padding shouldn't be counted as an information element
+#define PLEN(p, base)      (int)(ptrdiff_t)(p-base)
+#define PALIGN_4(p, base)  while (PLEN(p,base) & 0x3) *p++ = 0xFF;
+
+
+u64 USCounter;
+
+u16 SeqNo;
+
+bool BeaconDue;
+
+u8 PacketBuffer[2048];
+int PacketLen;
+int RXNum;
+
+
+bool Init()
+{
+    return true;
+}
+
+void DeInit()
+{
+}
+
+void Reset()
+{
+    // random starting point for the counter
+    USCounter = 0x428888017ULL;
+    SeqNo = 0x0120;
+
+    BeaconDue = false;
+
+    memset(PacketBuffer, 0, sizeof(PacketBuffer));
+    PacketLen = 0;
+    RXNum = 0;
+}
+
+
+void USTimer()
+{
+    USCounter++;
+
+    u32 chk = (u32)USCounter;
+    if (!(chk & 0x1FFFF))
+    {
+        // send beacon every 128ms
+        BeaconDue = true;
+    }
+}
+
+
+int SendPacket(u8* data, int len)
+{
+    //
+}
+
+int RecvPacket(u8* data)
+{
+    if (BeaconDue)
+    {
+        BeaconDue = false;
+
+        // craft beacon
+        u8* base = data + 12;
+        u8* p = base;
+
+        PWRITE_16(p, 0x0080);
+        PWRITE_16(p, 0x0000); // duration??
+        PWRITE_MAC(p, 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF); // recv
+        PWRITE_MAC2(p, APMac); // sender
+        PWRITE_MAC2(p, APMac); // BSSID
+        PWRITE_SEQNO(p);
+
+        PWRITE_64(p, USCounter);
+        PWRITE_16(p, 128); // beacon interval
+        PWRITE_16(p, 0x0021); // capability
+        PWRITE_8(p, 0x01); PWRITE_8(p, 0x02); PWRITE_8(p, 0x82); PWRITE_8(p, 0x84); // rates
+        PWRITE_8(p, 0x03); PWRITE_8(p, 0x01); PWRITE_8(p, 0x06); // current channel
+        PWRITE_8(p, 0x05); PWRITE_8(p, 0x04); PWRITE_8(p, 0); PWRITE_8(p, 0); PWRITE_8(p, 0); PWRITE_8(p, 0); // TIM
+        PWRITE_8(p, 0x00); PWRITE_8(p, strlen(AP_NAME));
+        memcpy(p, AP_NAME, strlen(AP_NAME)); p += strlen(AP_NAME);
+
+        PALIGN_4(p, base);
+        PWRITE_32(p, 0xDEADBEEF); // checksum. doesn't matter for now
+
+        int len = PLEN(p, base);
+        p = data;
+        PWRITE_TXH(p, len, 20);
+
+        /*static int zorp=0;
+        zorp++;
+        char derp[55];
+        sprintf(derp, "derpo%d.bin", zorp);
+        FILE* f = fopen(derp, "wb");
+        fwrite(data, len+12, 1, f);
+        fclose(f);*/
+
+        return len+12;
+    }
+
+    return 0;
+}
 
 }