304 lines
7.9 KiB
C++
304 lines
7.9 KiB
C++
#include "Tcp.h"
|
||
|
||
bool Callback(TinyIP* tip, void* param);
|
||
|
||
TcpSocket::TcpSocket(TinyIP* tip) : Socket(tip)
|
||
{
|
||
Type = IP_TCP;
|
||
|
||
Port = 0;
|
||
RemoteIP = 0;
|
||
RemotePort = 0;
|
||
LocalIP = 0;
|
||
LocalPort = 0;
|
||
|
||
seqnum = 0xa;
|
||
|
||
Status = Closed;
|
||
}
|
||
|
||
bool TcpSocket::Process(MemoryStream* ms)
|
||
{
|
||
TCP_HEADER* tcp = (TCP_HEADER*)ms->Current();
|
||
if(!ms->Seek(tcp->Length << 2)) return false;
|
||
|
||
Header = tcp;
|
||
uint len = ms->Remain();
|
||
|
||
ushort port = __REV16(tcp->DestPort);
|
||
ushort remotePort = __REV16(tcp->SrcPort);
|
||
|
||
// 仅处理本连接的IP和端口
|
||
if(Port != 0 && port != Port) return false;
|
||
if(RemotePort != 0 && remotePort != RemotePort) return false;
|
||
if(RemoteIP != 0 && Tip->RemoteIP != RemoteIP) return false;
|
||
|
||
// 不能修改主监听Socket的端口，否则可能导致收不到后续连接数据
|
||
//Port = port;
|
||
//RemotePort = remotePort;
|
||
//
|
||
//Tip->Port = port;
|
||
//Tip->RemotePort = remotePort;
|
||
|
||
// 第一次同步应答
|
||
if (tcp->Flags & TCP_FLAGS_SYN && !(tcp->Flags & TCP_FLAGS_ACK)) // SYN连接请求标志位，为1表示发起连接的请求数据包
|
||
{
|
||
if(OnAccepted)
|
||
OnAccepted(this, tcp, tcp->Next(), len);
|
||
else
|
||
{
|
||
#if NET_DEBUG
|
||
debug_printf("Tcp Accept "); // 打印发送方的ip
|
||
TinyIP::ShowIP(Tip->RemoteIP);
|
||
debug_printf("\r\n");
|
||
#endif
|
||
}
|
||
|
||
//第二次同步应答
|
||
Head(tcp, 1, true, false);
|
||
|
||
// 需要用到MSS，所以采用4个字节的可选段
|
||
//Send(tcp, 4, TCP_FLAGS_SYN | TCP_FLAGS_ACK);
|
||
// 注意tcp->Size()包括头部的扩展数据，这里不用单独填4
|
||
Send(tcp, 0, TCP_FLAGS_SYN | TCP_FLAGS_ACK);
|
||
|
||
return true;
|
||
}
|
||
// 第三次同步应答,三次应答后方可传输数据
|
||
if (tcp->Flags & TCP_FLAGS_ACK) // ACK确认标志位，为1表示此数据包为应答数据包
|
||
{
|
||
// 无数据返回ACK
|
||
if (len == 0)
|
||
{
|
||
if (tcp->Flags & (TCP_FLAGS_FIN | TCP_FLAGS_RST)) //FIN结束连接请求标志位。为1表示是结束连接的请求数据包
|
||
{
|
||
Head(tcp, 1, false, true);
|
||
Send(tcp, 0, TCP_FLAGS_ACK);
|
||
}
|
||
return true;
|
||
}
|
||
|
||
if(OnReceived)
|
||
{
|
||
// 返回值指示是否向对方发送数据包
|
||
bool rs = OnReceived(this, tcp, tcp->Next(), len);
|
||
if(!rs)
|
||
{
|
||
// 发送ACK，通知已收到
|
||
Head(tcp, 1, false, true);
|
||
Send(tcp, 0, TCP_FLAGS_ACK);
|
||
return true;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
#if NET_DEBUG
|
||
debug_printf("Tcp Data(%d) From ", len);
|
||
TinyIP::ShowIP(RemoteIP);
|
||
debug_printf(" : ");
|
||
Sys.ShowString(tcp->Next(), len);
|
||
debug_printf("\r\n");
|
||
#endif
|
||
}
|
||
// 发送ACK，通知已收到
|
||
Head(tcp, len, false, true);
|
||
//Send(buf, 0, TCP_FLAGS_ACK);
|
||
|
||
//TcpSend(buf, len);
|
||
|
||
// 响应Ack和发送数据一步到位
|
||
Send(tcp, len, TCP_FLAGS_ACK | TCP_FLAGS_PUSH);
|
||
}
|
||
else if(tcp->Flags & (TCP_FLAGS_FIN | TCP_FLAGS_RST))
|
||
{
|
||
if(OnDisconnected) OnDisconnected(this, tcp, tcp->Next(), len);
|
||
|
||
// RST是对方紧急关闭，这里啥都不干
|
||
if(tcp->Flags & TCP_FLAGS_FIN)
|
||
{
|
||
Head(tcp, 1, false, true);
|
||
//Close(tcp, 0);
|
||
Send(tcp, 0, TCP_FLAGS_ACK | TCP_FLAGS_PUSH | TCP_FLAGS_FIN);
|
||
}
|
||
}
|
||
|
||
return true;
|
||
}
|
||
|
||
void TcpSocket::Send(TCP_HEADER* tcp, uint len, byte flags)
|
||
{
|
||
tcp->SrcPort = __REV16(Port);
|
||
tcp->DestPort = __REV16(RemotePort);
|
||
tcp->Flags = flags;
|
||
if(tcp->Length < sizeof(TCP_HEADER) / 4) tcp->Length = sizeof(TCP_HEADER) / 4;
|
||
|
||
// 必须在校验码之前设置，因为计算校验码需要地址
|
||
Tip->RemoteIP = RemoteIP;
|
||
|
||
// 网络序是大端
|
||
tcp->Checksum = 0;
|
||
tcp->Checksum = __REV16(Tip->CheckSum((byte*)tcp, tcp->Size() + len, 2));
|
||
|
||
debug_printf("SendTcp: Flags=0x%02x, len=%d(0x%x) %d => %d \r\n", flags, tcp->Length, tcp->Length, __REV16(tcp->SrcPort), __REV16(tcp->DestPort));
|
||
|
||
// 注意tcp->Size()包括头部的扩展数据
|
||
Tip->SendIP(IP_TCP, (byte*)tcp, tcp->Size() + len);
|
||
}
|
||
|
||
void TcpSocket::Head(TCP_HEADER* tcp, uint ackNum, bool mss, bool opSeq)
|
||
{
|
||
/*
|
||
第一次握手：主机A发送位码为SYN＝1，随机产生Seq=1234567的数据包到服务器，主机B由SYN=1知道，A要求建立联机
|
||
第二次握手：主机B收到请求后要确认联机信息，向A发送Ack=(主机A的Seq+1)，SYN=1，Ack=1，随机产生Seq=7654321的包
|
||
第三次握手：主机A收到后检查Ack是否正确，即第一次发送的Seq+1，以及位码Ack是否为1，
|
||
若正确，主机A会再发送Ack=(主机B的Seq+1)，Ack=1，主机B收到后确认Seq值与Ack=1则连接建立成功。
|
||
完成三次握手，主机A与主机B开始传送数据。
|
||
*/
|
||
//TCP_HEADER* tcp = Header;
|
||
int ack = tcp->Ack;
|
||
tcp->Ack = __REV(__REV(tcp->Seq) + ackNum);
|
||
if (!opSeq)
|
||
{
|
||
// 我们仅仅递增第二个字节，这将允许我们以256或者512字节来发包
|
||
tcp->Seq = __REV(seqnum << 8);
|
||
// step the inititial seq num by something we will not use
|
||
// during this tcp session:
|
||
seqnum += 2;
|
||
/*tcp->Seq = __REV(seqnum);
|
||
seqnum++;*/
|
||
//tcp->Seq = 0;
|
||
}else
|
||
{
|
||
tcp->Seq = ack;
|
||
}
|
||
|
||
tcp->Length = sizeof(TCP_HEADER) / 4;
|
||
// 头部后面可能有可选数据，Length决定头部总长度（4的倍数）
|
||
if (mss)
|
||
{
|
||
uint* p = (uint*)tcp->Next();
|
||
// 使用可选域设置 MSS 到 1460:0x5b4
|
||
p[0] = __REV(0x020405b4);
|
||
p[1] = __REV(0x01030302);
|
||
p[2] = __REV(0x01010402);
|
||
|
||
tcp->Length += 3;
|
||
}
|
||
}
|
||
|
||
TCP_HEADER* TcpSocket::Create()
|
||
{
|
||
return (TCP_HEADER*)(Tip->Buffer + sizeof(ETH_HEADER) + sizeof(IP_HEADER));
|
||
}
|
||
|
||
void TcpSocket::Ack(uint len)
|
||
{
|
||
TCP_HEADER* tcp = Create();
|
||
tcp->Init(true);
|
||
Send(tcp, len, TCP_FLAGS_ACK | TCP_FLAGS_PUSH);
|
||
}
|
||
|
||
void TcpSocket::Close()
|
||
{
|
||
debug_printf("Tcp::Close ");
|
||
Tip->ShowIP(RemoteIP);
|
||
debug_printf(":%d \r\n", RemotePort);
|
||
|
||
TCP_HEADER* tcp = Create();
|
||
tcp->Init(true);
|
||
Send(tcp, 0, TCP_FLAGS_ACK | TCP_FLAGS_PUSH | TCP_FLAGS_FIN);
|
||
}
|
||
|
||
void TcpSocket::Send(byte* buf, uint len)
|
||
{
|
||
debug_printf("Tcp::Send ");
|
||
Tip->ShowIP(RemoteIP);
|
||
debug_printf(":%d buf=0x%08x len=%d ...... \r\n", RemotePort, buf, len);
|
||
|
||
TCP_HEADER* tcp = Create();
|
||
tcp->Init(true);
|
||
byte* end = Tip->Buffer + Tip->BufferSize;
|
||
if(buf < tcp->Next() || buf >= end)
|
||
{
|
||
// 复制数据，确保数据不会溢出
|
||
uint len2 = Tip->BufferSize - tcp->Offset() - tcp->Size();
|
||
assert_param(len <= len2);
|
||
|
||
memcpy(tcp->Next(), buf, len);
|
||
}
|
||
|
||
Send(tcp, len, TCP_FLAGS_PUSH);
|
||
|
||
Tip->LoopWait(Callback, this, 5000);
|
||
|
||
if(tcp->Flags & TCP_FLAGS_ACK)
|
||
debug_printf("发送成功！\r\n");
|
||
else
|
||
debug_printf("发送失败！\r\n");
|
||
}
|
||
|
||
// 连接远程服务器，记录远程服务器IP和端口，后续发送数据和关闭连接需要
|
||
bool TcpSocket::Connect(IPAddress ip, ushort port)
|
||
{
|
||
debug_printf("Tcp::Connect ");
|
||
Tip->ShowIP(ip);
|
||
debug_printf(":%d ...... \r\n", port);
|
||
|
||
RemoteIP = ip;
|
||
RemotePort = port;
|
||
|
||
TCP_HEADER* tcp = Create();
|
||
tcp->Init(true);
|
||
tcp->Seq = 0;
|
||
//seqnum = 0;
|
||
Head(tcp, 0, true, false);
|
||
|
||
Status = SynSent;
|
||
Send(tcp, 0, TCP_FLAGS_SYN);
|
||
|
||
if(Tip->LoopWait(Callback, this, 5000))
|
||
{
|
||
if(tcp->Flags & TCP_FLAGS_SYN)
|
||
{
|
||
Status = Established;
|
||
debug_printf("连接成功！\r\n");
|
||
return true;
|
||
}
|
||
Status = Closed;
|
||
debug_printf("拒绝连接！\r\n");
|
||
return false;
|
||
}
|
||
|
||
Status = Closed;
|
||
debug_printf("连接超时！\r\n");
|
||
return false;
|
||
}
|
||
|
||
bool Callback(TinyIP* tip, void* param)
|
||
{
|
||
ETH_HEADER* eth = (ETH_HEADER*)tip->Buffer;
|
||
if(eth->Type != ETH_IP) return false;
|
||
|
||
IP_HEADER* _ip = (IP_HEADER*)eth->Next();
|
||
if(_ip->Protocol != IP_TCP) return false;
|
||
|
||
TcpSocket* socket = (TcpSocket*)param;
|
||
TCP_HEADER* tcp = (TCP_HEADER*)_ip->Next();
|
||
// 检查端口
|
||
if(tcp->DestPort != socket->Port) return false;
|
||
|
||
socket->Header = tcp;
|
||
|
||
//if(Status == SynSent)
|
||
{
|
||
// 处理。如果对方回发第二次握手包，或者终止握手
|
||
MemoryStream ms(tip->Buffer, tip->BufferSize);
|
||
socket->Process(&ms);
|
||
}
|
||
//else
|
||
{
|
||
}
|
||
|
||
return true;
|
||
}
|