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WiFi: Clean up and refactor some more stuff, mostly related to LLC/SNAP encapsulated 802.11 frames.

This commit is contained in:
rogerman 2018-10-07 21:02:19 -07:00
parent 7fda7997b2
commit e3653b76ce
2 changed files with 101 additions and 45 deletions
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127
desmume/src/wifi.cpp
View File

@ -98,6 +98,7 @@ static const bool BBIsDataWritable[105] = {
};
static const u16 RFPinsLUT[10] = {0x04, 0x84, 0, 0x46, 0, 0x84, 0x87, 0, 0x46, 0x04};
static const WifiLLCSNAPHeader DefaultSNAPHeader = { 0xAA, 0xAA, 0x03, {0x00, 0x00, 0x00}, 0x0800 };
LegacyWifiSFormat legacyWifiSF;
DummyPCapInterface dummyPCapInterface;
@ -314,6 +315,11 @@ INLINE bool WIFI_isBroadcastMAC(const u8 *a)
return ((*(u32*)&a[0]) == 0xFFFFFFFF) && ((*(u16*)&a[4]) == 0xFFFF);
}
INLINE bool WIFI_IsLLCSNAPHeader(const u8 *snapHeader)
{
return ( (*(u16 *)&snapHeader[0] == *(u16 *)&DefaultSNAPHeader.dsap) && (*(u32 *)&snapHeader[2] == *(u32 *)&DefaultSNAPHeader.control) );
}
/*******************************************************************************
CRC32 (http://www.codeproject.com/KB/recipes/crc32_large.aspx)
@ -574,6 +580,21 @@ static void WIFI_triggerIRQ(const WifiIRQ irq)
}
}
TXPacketHeader WIFI_GenerateTXHeader(bool isTXRate20, size_t txLength)
{
TXPacketHeader txHeader;
txHeader.txStatus = 1;
txHeader.mpSlaves = 0;
txHeader.seqNumberControl = 0;
txHeader.UNKNOWN1 = 0;
txHeader.UNKNOWN2 = 0;
txHeader.txRate = (isTXRate20) ? 20 : 10;
txHeader.UNKNOWN3 = 0;
txHeader.length = txLength;
return txHeader;
}
RXPacketHeader WIFI_GenerateRXHeader(const u8 *packetIEEE80211HeaderPtr, const u16 timeStamp, const bool isTXRate20, const u16 emuPacketSize)
{
const WIFI_IOREG_MAP &io = wifiHandler->GetWifiData().io;
@ -3339,16 +3360,16 @@ static void SoftAP_RXPacketGet_Callback(u_char *userData, const pcap_pkthdr *pkt
}
// This is the smallest possible frame size there can be. As of this time:
// 14 bytes - The IEEE 802.3 frame header size (WifiEthernetFrameHeader)
// 14 bytes - The IEEE 802.3 frame header size (EthernetFrameHeader)
// 4 bytes - Size of the FCS at the end of every IEEE 802.3 frame. (not included because libpcap is not guaranteed to include this)
if (pktHeader->len <= sizeof(WifiEthernetFrameHeader))
if (pktHeader->len <= sizeof(EthernetFrameHeader))
{
return; // The packet is too small to be of any use.
}
// Check the 802.3 header and do a precheck on the relevant MAC addresses to see
// if we can reject the packet early.
const WifiEthernetFrameHeader &IEEE8023Header = (WifiEthernetFrameHeader &)pktData[0];
const EthernetFrameHeader &IEEE8023Header = (EthernetFrameHeader &)pktData[0];
if ( !(WIFI_compareMAC(io.MACADDR, IEEE8023Header.destMAC) || (WIFI_isBroadcastMAC(IEEE8023Header.destMAC) && WIFI_compareMAC(io.BSSID, SoftAP_MACAddr))) )
{
// Don't process packets that aren't for us.
@ -3361,7 +3382,7 @@ static void SoftAP_RXPacketGet_Callback(u_char *userData, const pcap_pkthdr *pkt
}
// Determine the NDS-compatible RX packet size and store in the emulator header.
const u32 rxPacketGetSize = pktHeader->len - sizeof(WifiEthernetFrameHeader);
const u32 rxPacketGetSize = pktHeader->len - sizeof(EthernetFrameHeader);
emulatorHeader.emuPacketSize = ((sizeof(WifiDataFrameHeaderDS2STA) + 8 + rxPacketGetSize) + 3) & 0xFFFC;
// Convert the libpcap 802.3 header into an NDS-compatible 802.11 header.
@ -3393,21 +3414,14 @@ static void SoftAP_RXPacketGet_Callback(u_char *userData, const pcap_pkthdr *pkt
IEEE80211Header.sendMAC[5] = IEEE8023Header.sendMAC[5];
IEEE80211Header.seqCtl.value = 0; // This is 0 for now, but will need to be set later.
// 802.3 to 802.11 LLC/SNAP header
WifiLLCSNAPHeader &snapHeader = (WifiLLCSNAPHeader &)rxTargetBuffer[sizeof(DesmumeFrameHeader) + sizeof(WifiDataFrameHeaderDS2STA)];
snapHeader = DefaultSNAPHeader;
snapHeader.ethertype = IEEE8023Header.ethertype;
// Packet body
u8 *packetBody = rxTargetBuffer + sizeof(DesmumeFrameHeader) + sizeof(WifiDataFrameHeaderDS2STA);
packetBody[0] = 0xAA;
packetBody[1] = 0xAA;
packetBody[2] = 0x03;
packetBody[3] = 0x00;
packetBody[4] = 0x00;
packetBody[5] = 0x00;
packetBody[6] = (IEEE8023Header.length & 0x00FF);
packetBody[7] = (IEEE8023Header.length & 0xFF00) >> 8;
packetBody += 8;
// Copy the packet body.
memcpy(packetBody, (u8 *)pktData + sizeof(WifiEthernetFrameHeader), rxPacketGetSize);
u8 *packetBody = rxTargetBuffer + sizeof(DesmumeFrameHeader) + sizeof(WifiDataFrameHeaderDS2STA) + sizeof(WifiLLCSNAPHeader);
memcpy(packetBody, (u8 *)pktData + sizeof(EthernetFrameHeader), rxPacketGetSize);
}
void DummyPCapInterface::__CopyErrorString(char *errbuf)
@ -3959,7 +3973,7 @@ void AdhocCommInterface::SendPacket(const TXPacketHeader &txHeader, const u8 *pa
const size_t emulatorHeaderSize = sizeof(DesmumeFrameHeader);
const size_t emulatorPacketSize = emulatorHeaderSize + txHeader.length;
DesmumeFrameHeader emulatorHeader;
DesmumeFrameHeader &emulatorHeader = (DesmumeFrameHeader &)this->_workingTXBuffer[0];
strncpy(emulatorHeader.frameID, DESMUME_EMULATOR_FRAME_ID, 8);
emulatorHeader.version = DESMUME_EMULATOR_FRAME_CURRENT_VERSION;
emulatorHeader.timeStamp = 0;
@ -3968,12 +3982,11 @@ void AdhocCommInterface::SendPacket(const TXPacketHeader &txHeader, const u8 *pa
emulatorHeader.packetAttributes.value = 0;
emulatorHeader.packetAttributes.IsTXRate20 = (txHeader.txRate == 20) ? 1 : 0;
memcpy(this->_workingTXBuffer, &emulatorHeader, sizeof(DesmumeFrameHeader));
memcpy(this->_workingTXBuffer + emulatorHeaderSize, packetData, txHeader.length);
size_t nbytes = sendto(thisSocket, (const char *)this->_workingTXBuffer, emulatorPacketSize, 0, &thisSendAddr, sizeof(sockaddr_t));
WIFI_LOG(4, "Ad-hoc: sent %i/%i bytes of packet, frame control: %04X\n", (int)nbytes, (int)emulatorPacketSize, *(u16 *)(packetData + sizeof(DesmumeFrameHeader)));
WIFI_LOG(4, "Ad-hoc: sent %i/%i bytes of packet, frame control: %04X\n", (int)nbytes, (int)emulatorPacketSize, *(u16 *)packetData);
}
size_t AdhocCommInterface::RXPacketGet(u8 *rxTargetBuffer)
@ -4009,7 +4022,7 @@ size_t AdhocCommInterface::RXPacketGet(u8 *rxTargetBuffer)
// 16 bytes - The smallest emulator frame header size (DesmumeFrameHeader)
// 10 bytes - The smallest possible IEEE 802.11 frame header size (WifiCtlFrameHeaderCTS/WifiCtlFrameHeaderACK)
// 4 bytes - Size of the FCS at the end of every IEEE 802.11 frame
if (rxPacketSizeInt <= (8 + 10 + 4))
if (rxPacketSizeInt <= (16 + 10 + 4))
{
return rxPacketSize; // The packet is too small to be of any use.
}
@ -4296,7 +4309,7 @@ void SoftAPCommInterface::Stop()
void SoftAPCommInterface::SendPacket(const TXPacketHeader &txHeader, const u8 *packetData)
{
WIFI_IOREG_MAP &io = wifiHandler->GetWifiData().io;
WifiFrameControl &fc = (WifiFrameControl &)packetData[0];
const WifiFrameControl &fc = (WifiFrameControl &)packetData[0];
WIFI_LOG(3, "SoftAP: Received a packet of length %i bytes. Frame control = %04X\n",
(int)txHeader.length, fc.value);
@ -4362,13 +4375,23 @@ void SoftAPCommInterface::SendPacket(const TXPacketHeader &txHeader, const u8 *p
}
case WifiFrameManagementSubtype_Disassociation:
{
this->_status = APStatus_Authenticated;
const u16 reasonCode = *(u16 *)mgmtFrameBody;
if (reasonCode != 0)
{
WIFI_LOG(1, "SoftAP disassocation error. ReasonCode=%d\n", (int)reasonCode);
}
return;
}
case WifiFrameManagementSubtype_Deauthentication:
{
const u16 reasonCode = *(u16 *)mgmtFrameBody;
this->_status = APStatus_Disconnected;
WIFI_LOG(1, "SoftAP disconnected.\n");
WIFI_LOG(1, "SoftAP disconnected. ReasonCode=%d\n", (int)reasonCode);
this->PacketCaptureFileClose();
return;
}
@ -4409,38 +4432,56 @@ void SoftAPCommInterface::SendPacket(const TXPacketHeader &txHeader, const u8 *p
case WifiFrameType_Data:
{
// If it has a LLC/SLIP header, send it over the Ethernet
if ((*(u16 *)&packetData[24] == 0xAAAA) && (*(u16 *)&packetData[26] == 0x0003) && (*(u16 *)&packetData[28] == 0x0000))
const WifiDataFrameHeaderSTA2DS &IEEE80211FrameHeader = (WifiDataFrameHeaderSTA2DS &)packetData[0];
// If it has an LLC/SNAP header, send it over the Ethernet.
if ( WIFI_IsLLCSNAPHeader(packetData + sizeof(WifiDataFrameHeaderSTA2DS)) )
{
const WifiLLCSNAPHeader &snapHeader = (WifiLLCSNAPHeader &)packetData[sizeof(WifiDataFrameHeaderSTA2DS)];
const u8 *inFrameBody = packetData + sizeof(WifiDataFrameHeaderSTA2DS) + sizeof(WifiLLCSNAPHeader);
if (this->_status != APStatus_Associated)
{
return;
if (this->_IsDNSRequestToWFC(*(u16 *)&packetData[30], &packetData[32]))
}
if (this->_IsDNSRequestToWFC(snapHeader.ethertype, inFrameBody))
{
// Removed to allow WFC communication.
//SoftAP_Deauthenticate();
//return;
}
u32 epacketLen = ((txHeader.length - 30 - 4) + 14);
u8 epacket[2048];
//printf("----- SENDING ETHERNET PACKET: len=%i, ethertype=%04X -----\n",
// len, *(u16*)&packet[30]);
memcpy(&epacket[0], &packetData[16], 6);
memcpy(&epacket[6], &packetData[10], 6);
*(u16 *)&epacket[12] = *(u16 *)&packetData[30];
memcpy(&epacket[14], &packetData[32], epacketLen - 14);
EthernetFrameHeader &IEEE8023FrameHeader = (EthernetFrameHeader &)this->_workingTXBuffer[0];
u8 *sendFrameBody = this->_workingTXBuffer + sizeof(EthernetFrameHeader);
IEEE8023FrameHeader.destMAC[0] = IEEE80211FrameHeader.destMAC[0];
IEEE8023FrameHeader.destMAC[1] = IEEE80211FrameHeader.destMAC[1];
IEEE8023FrameHeader.destMAC[2] = IEEE80211FrameHeader.destMAC[2];
IEEE8023FrameHeader.destMAC[3] = IEEE80211FrameHeader.destMAC[3];
IEEE8023FrameHeader.destMAC[4] = IEEE80211FrameHeader.destMAC[4];
IEEE8023FrameHeader.destMAC[5] = IEEE80211FrameHeader.destMAC[5];
IEEE8023FrameHeader.sendMAC[0] = IEEE80211FrameHeader.sendMAC[0];
IEEE8023FrameHeader.sendMAC[1] = IEEE80211FrameHeader.sendMAC[1];
IEEE8023FrameHeader.sendMAC[2] = IEEE80211FrameHeader.sendMAC[2];
IEEE8023FrameHeader.sendMAC[3] = IEEE80211FrameHeader.sendMAC[3];
IEEE8023FrameHeader.sendMAC[4] = IEEE80211FrameHeader.sendMAC[4];
IEEE8023FrameHeader.sendMAC[5] = IEEE80211FrameHeader.sendMAC[5];
IEEE8023FrameHeader.ethertype = snapHeader.ethertype;
const size_t sendPacketSize = txHeader.length - sizeof(WifiDataFrameHeaderSTA2DS) - sizeof(WifiLLCSNAPHeader) - sizeof(u32) + sizeof(EthernetFrameHeader);
memcpy(sendFrameBody, inFrameBody, sendPacketSize - sizeof(EthernetFrameHeader));
if (this->_bridgeDevice != NULL)
{
#if WIFI_SAVE_PCAP_TO_FILE
// Store the packet in the PCAP file.
this->PacketCaptureFileWrite(epacket, epacketLen, false);
this->PacketCaptureFileWrite(this->_workingTXBuffer, sendPacketSize, false);
#endif
// Send it
this->_pcap->sendpacket(this->_bridgeDevice, epacket, epacketLen);
this->_pcap->sendpacket(this->_bridgeDevice, this->_workingTXBuffer, sendPacketSize);
}
}
else

19
desmume/src/wifi.h
View File

@ -3036,8 +3036,22 @@ typedef struct
{
u8 destMAC[6];
u8 sendMAC[6];
u16 length;
} WifiEthernetFrameHeader;
union
{
u16 length;
u16 ethertype;
};
} EthernetFrameHeader;
typedef struct
{
u8 dsap;
u8 ssap;
u8 control;
u8 encapsulation[3];
u16 ethertype;
} WifiLLCSNAPHeader;
// NDS Frame Header Information
typedef struct
@ -3171,6 +3185,7 @@ protected:
u8 *_workingRXBuffer;
FILE *_packetCaptureFile; // PCAP file to store the Ethernet packets.
public:
WifiCommInterface();
virtual ~WifiCommInterface();