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UDP: forward received data

This commit is contained in:
Arisotura 2019-03-09 22:41:56 +01:00
parent d59a52df1f
commit 5edf40f665
1 changed files with 62 additions and 4 deletions
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66
src/libui_sdl/LAN_Socket.cpp
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@ -156,8 +156,10 @@ void FinishUDPFrame(u8* data, int len)
tmp += ntohs(*(u16*)&ipheader[18]);
tmp += ntohs(0x1100);
tmp += (len-0x22);
for (u8* i = udpheader; i < &udpheader[len-0x22]; i += 2)
for (u8* i = udpheader; i < &udpheader[len-0x23]; i += 2)
tmp += ntohs(*(u16*)i);
if (len & 1)
tmp += ntohs((u_short)udpheader[len-0x23]);
while (tmp >> 16)
tmp = (tmp & 0xFFFF) + (tmp >> 16);
tmp ^= 0xFFFF;
@ -484,6 +486,53 @@ void HandleDNSFrame(u8* data, int len)
RXNum = 1;
}
void UDP_BuildIncomingFrame(UDPSocket* sock, u8* data, int len)
{
u8 resp[2048];
u8* out = &resp[0];
if (len > 1536) return;
// ethernet
memcpy(out, Wifi::GetMAC(), 6); out += 6; // hurf
memcpy(out, kServerMAC, 6); out += 6;
*(u16*)out = htons(0x0800); out += 2;
// IP
u8* resp_ipheader = out;
*out++ = 0x45;
*out++ = 0x00;
*(u16*)out = 0; out += 2; // total length
*(u16*)out = htons(IPv4ID); out += 2; IPv4ID++;
*out++ = 0x00;
*out++ = 0x00;
*out++ = 0x80; // TTL
*out++ = 0x11; // protocol (UDP)
*(u16*)out = 0; out += 2; // checksum
memcpy(out, sock->DestIP, 4); out += 4; // source IP
*(u32*)out = htonl(kClientIP); out += 4; // destination IP
// UDP
u8* resp_tcpheader = out;
*(u16*)out = htons(sock->DestPort); out += 2; // source port
*(u16*)out = htons(sock->SourcePort); out += 2; // destination port
*(u16*)out = htons(len+8); out += 2; // length of header+data
*(u16*)out = 0; out += 2; // checksum
memcpy(out, data, len); out += len;
u32 framelen = (u32)(out - &resp[0]);
FinishUDPFrame(resp, framelen);
// TODO: if there is already a packet queued, this will overwrite it
// that being said, this will only happen during DHCP setup, so probably
// not a big deal
PacketLen = framelen;
memcpy(PacketBuffer, resp, PacketLen);
RXNum = 1;
}
void HandleUDPFrame(u8* data, int len)
{
u8* ipheader = &data[0xE];
@ -534,14 +583,18 @@ void HandleUDPFrame(u8* data, int len)
sock->Backend = socket(AF_INET, SOCK_DGRAM, 0);
memcpy(sock->DestIP, &ipheader[16], 4);
sock->SourcePort = srcport;
sock->DestPort = dstport;
memset(&sock->BackendAddr, 0, sizeof(sock->BackendAddr));
sock->BackendAddr.sin_family = AF_INET;
sock->BackendAddr.sin_port = htons(dstport);
memcpy(&sock->BackendAddr.sin_addr, &ipheader[16], 4);
if (bind(sock->Backend, (struct sockaddr*)&sock->BackendAddr, sizeof(sock->BackendAddr)) == SOCKET_ERROR)
/*if (bind(sock->Backend, (struct sockaddr*)&sock->BackendAddr, sizeof(sock->BackendAddr)) == SOCKET_ERROR)
{
printf("bind() shat itself :(\n");
}
}*/
printf("LANMAGIC: opening UDP socket #%d to %d.%d.%d.%d:%d, srcport %d\n",
sockid,
@ -1030,8 +1083,13 @@ int RecvPacket(u8* data)
int recvlen = recvfrom(sock->Backend, (char*)recvbuf, 1024, 0, &fromAddr, &fromLen);
if (recvlen < 1) continue;
if (fromAddr.sa_family != AF_INET) continue;
struct sockaddr_in* fromAddrIn = (struct sockaddr_in*)&fromAddr;
if (memcmp(&fromAddrIn->sin_addr, sock->DestIP, 4)) continue;
if (ntohs(fromAddrIn->sin_port) != sock->DestPort) continue;
printf("UDP: socket %d receiving %d bytes\n", i, recvlen);
//TCP_BuildIncomingFrame(sock, recvbuf, recvlen);
UDP_BuildIncomingFrame(sock, recvbuf, recvlen);
}
return ret;