509 lines
12 KiB
C++
509 lines
12 KiB
C++
#include "Tcp.h"
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#include "Kernel\WaitHandle.h"
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#define NET_DEBUG 0
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//#define NET_DEBUG DEBUG
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bool Callback(TinyIP* tip, void* param, Stream& ms);
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TcpSocket::TcpSocket(TinyIP* tip) : TinySocket(tip, IP_TCP)
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{
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MaxSize = 1500;
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Host = tip;
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Protocol = NetType::Tcp;
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// 累加端口
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static ushort g_tcp_port = 1024;
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if(g_tcp_port < 1024) g_tcp_port = 1024;
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Local.Port = g_tcp_port++;
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Local.Address = tip->IP;
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// 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
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static uint seqnum = 0xa;
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Seq = seqnum << 8;
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seqnum += 2;
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Ack = 0;
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Status = Closed;
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OnAccepted = nullptr;
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OnReceived = nullptr;
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OnDisconnected = nullptr;
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}
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/*cstring TcpSocket::ToString() const
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{
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static char name[10];
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sprintf(name, "TCP_%d", Local.Port);
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return name;
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}*/
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String& TcpSocket::ToStr(String& str) const
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{
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return str + "TCP_" + Local.Port;
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}
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bool TcpSocket::OnOpen()
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{
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debug_printf("Tcp::Open %d\r\n", Local.Port);
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Enable = true;
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return Enable;
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}
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void TcpSocket::OnClose()
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{
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debug_printf("Tcp::Close %d\r\n", Local.Port);
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Enable = false;
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Status = Closed;
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}
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bool TcpSocket::Process(IP_HEADER& ip, Stream& ms)
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{
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auto tcp = ms.Retrieve<TCP_HEADER>();
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if(!tcp) return false;
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Header = tcp;
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//uint len = ms.Remain();
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ushort port = _REV16(tcp->DestPort);
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//ushort remotePort = _REV16(tcp->SrcPort);
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// 仅处理本连接的IP和端口
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if(port != Local.Port) return false;
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//Local.Port = port;
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//Local.Address = ip.DestIP;
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if(_wait && (tcp->Flags & TCP_FLAGS_ACK))
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{
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((WaitHandle*)_wait)->Set();
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_wait = nullptr;
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}
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OnProcess(*tcp, ms);
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return true;
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}
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void TcpSocket::OnProcess(TCP_HEADER& tcp, Stream& ms)
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{
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// 计算标称的数据长度
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//uint len = tcp.Size() - sizeof(TCP_HEADER);
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// TCP好像没有标识数据长度的字段，但是IP里面有，这样子的话，ms里面的长度是准确的
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uint len = ms.Remain();
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uint seq = _REV(tcp.Seq);
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uint ack = _REV(tcp.Ack);
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#if NET_DEBUG
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debug_printf("Tcp::Process Flags=0x%02x Seq=0x%04x Ack=0x%04x From ", tcp.Flags, seq, ack);
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Remote.Show();
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debug_printf("\r\n");
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#endif
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// 下次主动发数据时，用该序列号，因为对方Ack确认期望下次得到这个序列号
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Seq = ack;
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Ack = seq + len;
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//debug_printf("Seq=0x%04x Ack=0x%04x \r\n", Seq, Ack);
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// 第一次同步应答
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if (tcp.Flags & TCP_FLAGS_SYN) // SYN连接请求标志位，为1表示发起连接的请求数据包
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{
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Ack++; // 此时加一
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if(!(tcp.Flags & TCP_FLAGS_ACK))
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OnAccept(tcp, len);
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else
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OnAccept3(tcp, len);
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}
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else if(tcp.Flags & (TCP_FLAGS_FIN | TCP_FLAGS_RST))
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{
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Ack++; // 此时加一
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OnDisconnect(tcp, len);
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}
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// 第三次同步应答,三次应答后方可传输数据
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else 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
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{
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if(len == 0 && tcp.Ack <= 1)
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OnAccept3(tcp, len);
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else
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OnDataReceive(tcp, len);
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}
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else
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debug_printf("Tcp::Process 未知标识位 0x%02x \r\n", tcp.Flags);
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}
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// 服务端收到握手二，也是首次收到来自客户端的数据
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void TcpSocket::OnAccept(TCP_HEADER& tcp, uint len)
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{
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if(Status == Closed) Status = SynSent;
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if(OnAccepted)
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OnAccepted(*this, tcp, tcp.Next(), len);
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else
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{
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#if NET_DEBUG
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debug_printf("Tcp:Accept "); // 打印发送方的ip
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Remote.Show();
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debug_printf("\r\n");
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#endif
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}
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//第二次同步应答
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SetSeqAck(tcp, 1, false);
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SetMss(tcp);
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// 需要用到MSS，所以采用4个字节的可选段
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//SendPacket(tcp, 4, TCP_FLAGS_SYN | TCP_FLAGS_ACK);
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// 注意tcp->Size()包括头部的扩展数据，这里不用单独填4
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SendPacket(tcp, 0, TCP_FLAGS_SYN | TCP_FLAGS_ACK);
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}
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// 客户端收到握手三，也是首次收到来自服务端的数据，或者0数据的ACK
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void TcpSocket::OnAccept3(TCP_HEADER& tcp, uint len)
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{
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if(Status == SynSent) Status = Established;
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if(OnAccepted)
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OnAccepted(*this, tcp, tcp.Next(), len);
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else
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{
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#if NET_DEBUG
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debug_printf("Tcp:Accept3 "); // 打印发送方的ip
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Remote.Show();
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debug_printf("\r\n");
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#endif
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}
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// 第二次同步应答
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SetSeqAck(tcp, 1, true);
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// 不需要Mss
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tcp.Length = sizeof(TCP_HEADER) / 4;
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SendPacket(tcp, 0, TCP_FLAGS_ACK);
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}
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void TcpSocket::OnDataReceive(TCP_HEADER& tcp, uint len)
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{
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// 无数据返回ACK
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if (len == 0)
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{
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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
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{
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SetSeqAck(tcp, 1, true);
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SendPacket(tcp, 0, TCP_FLAGS_ACK);
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}
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else
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{
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#if NET_DEBUG
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debug_printf("Tcp:Receive(%d) From ", len);
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Remote.Show();
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debug_printf("\r\n");
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#endif
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}
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return;
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}
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byte* data = tcp.Next();
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// 触发ITransport接口事件
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Buffer bs(data, len);
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uint len2 = OnReceive(bs, nullptr);
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// 如果有返回，说明有数据要回复出去
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if(len2)
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{
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// 发送ACK，通知已收到
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SetSeqAck(tcp, len, true);
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// 响应Ack和发送数据一步到位
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SendPacket(tcp, len2, TCP_FLAGS_ACK | TCP_FLAGS_PUSH);
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}
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if(OnReceived)
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{
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// 返回值指示是否向对方发送数据包
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bool rs = OnReceived(*this, tcp, data, len);
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// 如果不需要向对方发数据包，则直接响应ACK
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if(!rs)
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{
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// 发送ACK，通知已收到
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SetSeqAck(tcp, len, true);
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SendPacket(tcp, 0, TCP_FLAGS_ACK);
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return;
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}
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}
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else
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{
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#if NET_DEBUG
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debug_printf("Tcp:Receive(%d) From ", len);
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Remote.Show();
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debug_printf(" ");
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String(data, len).Show(true);
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#endif
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}
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// 发送ACK，通知已收到
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SetSeqAck(tcp, len, true);
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SendPacket(tcp, 0, TCP_FLAGS_ACK);
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// 响应Ack和发送数据一步到位
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//SendPacket(tcp, len, TCP_FLAGS_ACK | TCP_FLAGS_PUSH);
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}
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void TcpSocket::OnDisconnect(TCP_HEADER& tcp, uint len)
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{
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Status = Closed;
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if(OnDisconnected) OnDisconnected(*this, tcp, tcp.Next(), len);
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// RST是对方紧急关闭，这里啥都不干
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if(tcp.Flags & TCP_FLAGS_FIN)
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{
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SetSeqAck(tcp, 1, true);
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//Close(tcp, 0);
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SendPacket(tcp, 0, TCP_FLAGS_ACK | TCP_FLAGS_PUSH | TCP_FLAGS_FIN);
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}
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else if(!OnDisconnected)
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{
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#if NET_DEBUG
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debug_printf("Tcp:OnDisconnect "); // 打印发送方的ip
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Remote.Show();
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debug_printf(" Flags=0x%02x", tcp.Flags);
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debug_printf("\r\n");
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#endif
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}
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Status = Closed;
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}
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bool TcpSocket::SendPacket(TCP_HEADER& tcp, uint len, byte flags)
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{
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tcp.SrcPort = _REV16(Local.Port);
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tcp.DestPort = _REV16(Remote.Port);
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tcp.Flags = flags;
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tcp.WindowSize = _REV16(1024);
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if(tcp.Length < sizeof(TCP_HEADER) / 4) tcp.Length = sizeof(TCP_HEADER) / 4;
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// 必须在校验码之前设置，因为计算校验码需要地址
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//Tip->RemoteIP = RemoteIP;
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// 网络序是大端
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tcp.Checksum = 0;
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tcp.Checksum = _REV16(Tip->CheckSum(&Remote.Address, (byte*)&tcp, tcp.Size() + len, 2));
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#if NET_DEBUG
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uint hlen = tcp.Length << 2;
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debug_printf("SendTcp: Flags=0x%02x Seq=0x%04x Ack=0x%04x Length=%d(0x%x) Payload=%d(0x%x) %d => %d \r\n", flags, _REV(tcp.Seq), _REV(tcp.Ack), hlen, hlen, len, len, _REV16(tcp.SrcPort), _REV16(tcp.DestPort));
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#endif
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// 注意tcp->Size()包括头部的扩展数据
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return Tip->SendIP(IP_TCP, Remote.Address, (byte*)&tcp, tcp.Size() + len);
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}
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void TcpSocket::SetSeqAck(TCP_HEADER& tcp, uint ackNum, bool opSeq)
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{
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/*
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第一次握手：主机A发送位码为SYN＝1，随机产生Seq=x的数据包到服务器，主机B由SYN=1知道，A要求建立联机
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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=(A.Seq+1)，SYN=1，ACK=1，随机产生Seq=y的包
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第三次握手：主机A收到后检查Ack是否正确，即A.Seq+1，以及位码ACK是否为1，
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若正确，主机A会再发送Ack=(B.Seq+1)，ACK=1，主机B收到后确认Seq值与ACK=1则连接建立成功。
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完成三次握手，主机A与主机B开始传送数据。
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Seq 序列号。每一个字节都编号，本报文所发送数据的第一个字节的序号。
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Ack 确认号。期望收到对方的下一个报文的数据的第一个字节的序号。
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*/
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//TCP_HEADER* tcp = Header;
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uint ack = tcp.Ack;
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tcp.Ack = _REV(_REV(tcp.Seq) + ackNum);
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if (!opSeq)
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{
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tcp.Seq = _REV(Seq);
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}
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else
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{
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tcp.Seq = ack;
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//tcp.Seq = _REV(Seq);
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}
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}
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void TcpSocket::SetMss(TCP_HEADER& tcp)
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{
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tcp.Length = sizeof(TCP_HEADER) / 4;
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// 头部后面可能有可选数据，Length决定头部总长度（4的倍数）
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//if (mss)
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{
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uint* p = (uint*)tcp.Next();
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// 使用可选域设置 MSS 到 1460:0x5b4
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p[0] = _REV(0x020405b4);
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p[1] = _REV(0x01030302);
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p[2] = _REV(0x01010402);
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tcp.Length += 3;
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}
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}
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void TcpSocket::SendAck(uint len)
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{
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byte buf[1500];
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Stream ms(buf, sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(TCP_HEADER) + len);
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ms.Seek(sizeof(ETH_HEADER) + sizeof(IP_HEADER));
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auto tcp = ms.Retrieve<TCP_HEADER>();
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tcp->Init(true);
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SendPacket(*tcp, len, TCP_FLAGS_ACK | TCP_FLAGS_PUSH);
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}
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bool TcpSocket::Disconnect()
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{
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debug_printf("Tcp::Disconnect ");
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Remote.Show();
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debug_printf("\r\n");
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byte buf[1500];
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Stream ms(buf, sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(TCP_HEADER));
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ms.Seek(sizeof(ETH_HEADER) + sizeof(IP_HEADER));
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auto tcp = ms.Retrieve<TCP_HEADER>();
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tcp->Init(true);
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return SendPacket(*tcp, 0, TCP_FLAGS_ACK | TCP_FLAGS_PUSH | TCP_FLAGS_FIN);
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}
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bool TcpSocket::Send(const Buffer& bs)
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{
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if(!Enable)
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{
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if(!Open()) return false;
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}
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// 如果连接已关闭，必须重新连接
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if(Status == Closed)
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{
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if(!Connect(Remote.Address, Remote.Port)) return false;
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}
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#if NET_DEBUG
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debug_printf("Tcp::Send ");
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Remote.Show();
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debug_printf(" buf=%p len=%d ...... \r\n", bs.GetBuffer(), bs.Length());
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#endif
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//Stream ms(sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(TCP_HEADER) + bs.Length());
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//byte buf[sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(TCP_HEADER) + 256];
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byte buf[1500];
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Stream ms(buf, ArrayLength(buf));
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ms.Seek(sizeof(ETH_HEADER) + sizeof(IP_HEADER));
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auto tcp = ms.Retrieve<TCP_HEADER>();
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tcp->Init(true);
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// 复制数据，确保数据不会溢出
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ms.Write(bs);
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//SetSeqAck(tcp, len, true);
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tcp->Seq = _REV(Seq);
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tcp->Ack = _REV(Ack);
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// 发送数据的时候，需要同时带PUSH和ACK
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//debug_printf("Seq=0x%04x Ack=0x%04x \r\n", Seq, Ack);
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if(!SendPacket(*tcp, bs.Length(), TCP_FLAGS_PUSH | TCP_FLAGS_ACK)) return false;
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// 等待响应
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WaitHandle wh;
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_wait = &wh;
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bool rs = wh.WaitOne(3000);
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#if NET_DEBUG
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if(rs)
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debug_printf("发送成功！\r\n");
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else
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debug_printf("发送失败！\r\n");
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#endif
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return rs;
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}
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uint TcpSocket::Receive(Buffer& bs)
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{
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return 0;
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}
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// 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
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bool TcpSocket::Connect(IPAddress& ip, ushort port)
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{
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if(ip.IsAny() || port == 0) return false;
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if(!Enable)
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{
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if(!Open()) return false;
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}
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Local.Address = Tip->IP;
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Remote.Address = ip;
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Remote.Port = port;
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debug_printf("Tcp::Connect ");
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Local.Show();
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debug_printf(" => ");
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Remote.Show();
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debug_printf(" ...... \r\n");
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byte buf[100];
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Stream ms(buf, sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(TCP_HEADER) + 3);
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ms.Seek(sizeof(ETH_HEADER) + sizeof(IP_HEADER));
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auto tcp = ms.Retrieve<TCP_HEADER>();
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tcp->Init(true);
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//tcp->Seq = 0; // 仅仅是为了Ack=0，tcp->Seq还是会被Socket的顺序Seq替代
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//SetSeqAck(tcp, 0, false);
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tcp->Seq = _REV(Seq);
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tcp->Ack = 0;
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SetMss(*tcp);
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Status = SynSent;
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if(!SendPacket(*tcp, 0, TCP_FLAGS_SYN))
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{
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Status = Closed;
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return false;
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}
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// 等待响应
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WaitHandle wh;
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_wait = &wh;
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if(wh.WaitOne(3000))
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{
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if(Status == Established)
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{
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//Status = Established;
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debug_printf("连接成功！\r\n");
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return true;
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}
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Status = Closed;
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debug_printf("拒绝连接！\r\n");
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return false;
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}
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Status = Closed;
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debug_printf("连接超时！\r\n");
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return false;
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}
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bool TcpSocket::OnWrite(const Buffer& bs)
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{
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return Send(bs);
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}
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uint TcpSocket::OnRead(Buffer& bs)
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{
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// 暂时不支持
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return 0;
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}
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/*
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三次握手过程：
|
||
A=>B SYN
|
||
B=>A SYN+ACK
|
||
A=>B ACK
|
||
*/
|