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somewhat better TCP

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still not perfect
This commit is contained in:
Arisotura 2019-03-09 00:47:55 +01:00
parent e026574901
commit f3f4613b4e
1 changed files with 54 additions and 0 deletions
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54
src/libui_sdl/LAN_Socket.cpp
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@ -538,6 +538,57 @@ void TCP_SYNACK(TCPSocket* sock, u8* data, int len)
RXNum = 1;
}
void TCP_ACK(TCPSocket* sock, u8* data, int len)
{
u8 resp[64];
u8* out = &resp[0];
u8* ipheader = &data[0xE];
u8* tcpheader = &data[0x22];
// ethernet
memcpy(out, &data[6], 6); out += 6;
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++ = 0x06; // protocol (TCP)
*(u16*)out = 0; out += 2; // checksum
*(u32*)out = *(u32*)&ipheader[16]; out += 4; // source IP
*(u32*)out = *(u32*)&ipheader[12]; out += 4; // destination IP
// TCP
u8* resp_tcpheader = out;
*(u16*)out = *(u16*)&tcpheader[2]; out += 2; // source port
*(u16*)out = *(u16*)&tcpheader[0]; out += 2; // destination port
*(u32*)out = htonl(sock->SeqNum); out += 4; // seq number
*(u32*)out = htonl(sock->AckNum); out += 4; // ack seq number
*(u16*)out = htons(0x5010); out += 2; // flags (ACK)
*(u16*)out = htons(0x7000); out += 2; // window size (uuuh)
*(u16*)out = 0; out += 2; // checksum
*(u16*)out = 0; out += 2; // urgent pointer
u32 framelen = (u32)(out - &resp[0]);
if (framelen & 1) { *out++ = 0; framelen++; }
FinishTCPFrame(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 TCP_BuildIncomingFrame(TCPSocket* sock, u8* data, int len)
{
u8 resp[2048];
@ -707,6 +758,9 @@ void HandleTCPFrame(u8* data, int len)
printf("TCP: socket %d sending %d bytes\n", sockid, tcpdatalen);
send(sock->Backend, (char*)tcpdata, tcpdatalen, 0);
// kind of a hack, there
TCP_ACK(sock, data, len);
}
if (flags & 0x001) // FIN