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Wifi: put in some parsing of DNS requests, and a warning when a DNS request to the WFC servers is detected, rather than just blocking any packet that contains "nintendowifi". 

The user has to confirm he wants to connect to WFC, otherwise SoftAP will deauthenticate (therefore breaking the connection). Note on the warning, for those who don't read warnings and just hit spacebar: I made the No button selected by default.
If someone really wants to just block WFC, atleast we've got a more proper detector now...
This commit is contained in:
luigi__ 2010-04-20 16:38:21 +00:00
parent 9dbac0c047
commit fb0db7b5ac
3 changed files with 115 additions and 37 deletions
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2
desmume/src/driver.h
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@ -49,6 +49,8 @@ public:
virtual bool WIFI_SocketsAvailable() { return true; }
virtual bool WIFI_PCapAvailable() { return false; }
virtual bool WIFI_WFCWarning() { return false; }
virtual int PCAP_findalldevs(pcap_if_t** alldevs, char* errbuf) { return -1; }
virtual void PCAP_freealldevs(pcap_if_t* alldevs) {}
virtual pcap_t* PCAP_open(const char* source, int snaplen, int flags, int readtimeout, char* errbuf) { return NULL; }

136
desmume/src/wifi.cpp
View File

@ -53,6 +53,8 @@
const u8 BroadcastMAC[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
bool bWFCUserWarned = false;
#ifdef EXPERIMENTAL_WIFI_COMM
socket_t wifi_socket = INVALID_SOCKET;
sockaddr_t sendAddr;
@ -301,7 +303,7 @@ WifiComInterface* wifiCom;
// 3: medium logging, for debugging, shows lots of stuff
// 4: high logging, for debugging, shows almost everything, may slow down
// 5: highest logging, for debugging, shows everything, may slow down a lot
#define WIFI_LOGGING_LEVEL 0
#define WIFI_LOGGING_LEVEL 1
#define WIFI_LOG_USE_LOGC 0
@ -653,6 +655,8 @@ bool WIFI_Init()
if(wifiCom)
wifiCom->Init();
bWFCUserWarned = false;
return true;
}
@ -679,6 +683,8 @@ void WIFI_Reset()
wifiCom = wifiComs[CommonSettings.wifi.mode];
if(wifiCom)
wifiCom->Reset();
bWFCUserWarned = false;
}
@ -1898,6 +1904,20 @@ const u8 SoftAP_AssocResponse[] = {
0x01, 0x02, 0x82, 0x84, // Supported rates
};
// Deauthentication frame - sent if the user chose not to connect to WFC
const u8 SoftAP_DeauthFrame[] = {
/* 802.11 header */
0xC0, 0x00, // Frame control
0x00, 0x00, // Duration ID
0x00, 0x09, 0xBF, 0x12, 0x34, 0x56, // Receiver
SOFTAP_MACADDR, // Sender
SOFTAP_MACADDR, // BSSID
0x00, 0x00, // Sequence control
/* Frame body */
0x01, 0x00, // Reason code (is "unspecified" ok?)
};
//todo - make a class to wrap this
//todo - zeromus - inspect memory leak safety of all this
static pcap_if_t * WIFI_index_device(pcap_if_t *alldevs, int index)
@ -1978,41 +1998,69 @@ void SoftAP_Reset()
SoftAP.seqNum = 0;
}
//I coded this up in a minute. is there a standard way of doing this or another function I can borrow?
static s32 searchmem(u8* data, u32 len, char* search)
static bool SoftAP_IsDNSRequestToWFC(u16 ethertype, u8* body)
{
s32 i=0;
u32 searchLen = strlen(search);
if(len==0) return -1;
if(searchLen==0) return -1;
for(;;)
// Check the various headers...
if (htons(ethertype) != 0x0800) return false; // EtherType: IP
if (body[0] != 0x45) return false; // Version: 4, header len: 5
if (body[9] != 0x11) return false; // Protocol: UDP
if (htons(*(u16*)&body[22]) != 53) return false; // Dest. port: 53 (DNS)
if ((*(u16*)&body[28+2]) & 0x8000) return false; // must be a query
// Analyze each question
u16 numquestions = htons(*(u16*)&body[28+4]);
u32 curoffset = 28+12;
for (u16 curquestion = 0; curquestion < numquestions; curquestion++)
{
u32 j=0;
s32 snap = i;
for(;i<len&&j<searchLen;i++,j++)
// Assemble the requested domain name
u8 bitlength = 0; char domainname[256] = "";
while ((bitlength = body[curoffset++]) != 0)
{
if(data[i] != search[j])
{
i++;
break;
}
strncat(domainname, (const char*)&body[curoffset], bitlength);
curoffset += bitlength;
if (body[curoffset] != 0)
strcat(domainname, ".");
}
if(j==searchLen)
return snap;
if(i==len)
break;
WIFI_LOG(1, "SoftAP: detected DNS request to %s\n", domainname);
// if the domain name contains nintendowifi.net
// it is most likely a WFC server
// (note, conntest.nintendowifi.net just contains a dummy HTML page and
// is used for connection tests, I think we can let this one slide)
if ((strstr(domainname, "nintendowifi.net") != NULL) &&
(strcmp(domainname, "conntest.nintendowifi.net") != 0))
return true;
// Skip the type and class - we don't care about that
curoffset += 4;
}
return -1;
return false;
}
static bool validatePacket(u8 *packet, u32 len)
static void SoftAP_Deauthenticate()
{
//reject DNS requests for nintendo. this is a rather blunt instrument right now.
//i suppose it would prevent someone from discussing nintendowifi on clirc!
//does someone know how to make an EZ dns parser?
if(searchmem(packet,len,"nintendowifi") == -1) return true;
else return false;
u32 packetLen = sizeof(SoftAP_DeauthFrame);
memcpy(&SoftAP.curPacket[12], SoftAP_DeauthFrame, packetLen); // Copy the beacon template
*(u16*)&SoftAP.curPacket[12 + 22] = SoftAP.seqNum << 4; // Sequence number
SoftAP.seqNum++;
u16 rxflags = 0x0010;
if (WIFI_compareMAC(wifiMac.bss.bytes, &SoftAP.curPacket[12 + 16]))
rxflags |= 0x8000;
WIFI_MakeRXHeader(SoftAP.curPacket, rxflags, 20, packetLen, 0, 0);
// Let's prepare to send
SoftAP.curPacketSize = packetLen + 12;
SoftAP.curPacketPos = 0;
SoftAP.curPacketSending = TRUE;
SoftAP.status = APStatus_Disconnected;
}
void SoftAP_SendPacket(u8 *packet, u32 len)
@ -2022,16 +2070,14 @@ void SoftAP_SendPacket(u8 *packet, u32 len)
WIFI_LOG(3, "SoftAP: Received a packet of length %i bytes. Frame control = %04X\n",
len, frameCtl);
if(!validatePacket(packet,len)) return;
//use this to log wifi messages easily
//static int ctr=0;
//char buf[100];
//sprintf(buf,"wifi%04d.txt",ctr);
//FILE* outf = fopen(buf,"wb");
//fwrite(packet,1,len,outf);
//fclose(outf);
//ctr++;
/*static int ctr=0;
char buf[100];
sprintf(buf,"wifi%04d.txt",ctr);
FILE* outf = fopen(buf,"wb");
fwrite(packet,1,len,outf);
fclose(outf);
ctr++;*/
switch((frameCtl >> 2) & 0x3)
{
@ -2114,6 +2160,22 @@ void SoftAP_SendPacket(u8 *packet, u32 len)
if (SoftAP.status != APStatus_Associated)
return;
if (!bWFCUserWarned && SoftAP_IsDNSRequestToWFC(*(u16*)&packet[30], &packet[32]))
{
// if the user chose not to connect to WFC
// disconnect them, and do not send the DNS packet
// otherwise just stop bothering them
if (driver->WIFI_WFCWarning())
{
bWFCUserWarned = true;
}
else
{
SoftAP_Deauthenticate();
return;
}
}
u32 epacketLen = ((len - 30 - 4) + 14);
u8 epacket[2048];

14
desmume/src/windows/main.cpp
View File

@ -2099,6 +2099,20 @@ class WinDriver : public BaseDriver
virtual bool WIFI_SocketsAvailable() { return bSocketsAvailable; }
virtual bool WIFI_PCapAvailable() { return bWinPCapAvailable; }
virtual bool WIFI_WFCWarning()
{
return MessageBox(NULL, "You are going to connect to the Nintendo WFC servers.\n"
"\n"
"Please keep in mind that DeSmuME is not perfect\n"
"and connecting to WFC may cause unexpected problems\n"
"to the WFC servers, which Nintendo would not appreciate.\n"
"\n"
"Do you still want to connect?",
"DeSmuME - WFC warning",
MB_YESNO | MB_DEFBUTTON2 | MB_ICONWARNING
) == IDYES;
}
virtual int PCAP_findalldevs(pcap_if_t** alldevs, char* errbuf) {
return _pcap_findalldevs(alldevs, errbuf); }