166 lines
3.7 KiB
C++
166 lines
3.7 KiB
C++
#include "TTime.h"
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#include "Icmp.h"
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#include "Arp.h"
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#include "WaitHandle.h"
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#define NET_DEBUG DEBUG
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class PingSession
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{
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public:
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IPAddress Address;
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ushort Identifier;
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ushort Sequence;
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WaitHandle Handle;
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PingSession(IPAddress& ip, ushort id, ushort seq)
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{
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Address = ip;
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Identifier = id;
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Sequence = seq;
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}
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bool Check(IPAddress& remote, ICMP_HEADER* icmp)
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{
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if(remote != Address) return false;
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if(Identifier != icmp->Identifier) return false;
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if(Sequence != icmp->Sequence) return false;
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return true;
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}
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};
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// 用于等待Ping响应的会话
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PingSession* _IcmpSession = nullptr;
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IcmpSocket::IcmpSocket(TinyIP* tip) : TinySocket(tip, IP_ICMP)
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{
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//Type = IP_ICMP;
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Enable = true;
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}
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bool IcmpSocket::Process(IP_HEADER& ip, Stream& ms)
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{
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auto icmp = ms.Retrieve<ICMP_HEADER>();
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if(!icmp) return false;
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IPAddress remote = ip.SrcIP;
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// 检查有没有会话等待
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if(icmp->Type == 0 && _IcmpSession != nullptr && _IcmpSession->Check(remote, icmp))
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{
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_IcmpSession->Handle.Set();
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_IcmpSession = nullptr;
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return true;
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}
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uint len = ms.Remain();
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if(OnPing)
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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 = OnPing(*this, *icmp, icmp->Next(), len);
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if(!rs) return true;
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}
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else
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{
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#if NET_DEBUG
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/*if(icmp->Type != 0)
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debug_printf("Ping From "); // 打印发方的ip
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else
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debug_printf("Ping Reply "); // 打印发方的ip*/
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switch(icmp->Type)
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{
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case 0:
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debug_printf("Ping Reply ");
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break;
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case 3:
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debug_printf("ICMP::应用端口不可达 ");
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break;
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case 8:
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debug_printf("Ping From ");
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break;
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default:
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debug_printf("ICMP%d ", icmp->Type);
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break;
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}
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remote.Show();
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debug_printf(" Payload=%d ", len);
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// 越过2个字节标识和2字节序列号
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debug_printf("ID=0x%04X Seq=0x%04X ", _REV16(icmp->Identifier), _REV16(icmp->Sequence));
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String((char*)icmp->Next(), len).Show(true);
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#endif
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}
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// 只处理ECHO请求
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if(icmp->Type != 8) return true;
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icmp->Type = 0; // 响应
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// 因为仅仅改变类型，因此我们能够提前修正校验码
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icmp->Checksum += 0x08;
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// 这里不能直接用sizeof(ICMP_HEADER)，而必须用len，因为ICMP包后面一般有附加数据
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Tip->SendIP(IP_ICMP, remote, (byte*)icmp, icmp->Size() + len);
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return true;
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}
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// Ping目的地址，附带a~z重复的负载数据
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bool IcmpSocket::Ping(IPAddress& ip, uint payloadLength)
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{
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byte buf[sizeof(ETH_HEADER) + sizeof(IP_HEADER) + sizeof(ICMP_HEADER) + 64];
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// 注意，此时指针位于0，而内容长度为缓冲区长度
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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 icmp = ms.Retrieve<ICMP_HEADER>();
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icmp->Init(true);
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icmp->Type = 8;
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icmp->Code = 0;
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// 限定最大长度64
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if(payloadLength > 64) payloadLength = 64;
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for(int i=0, k=0; i<payloadLength; i++, k++)
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{
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if(k >= 23) k-=23;
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ms.Write((byte)('a' + k));
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}
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ushort now = Sys.Ms();
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ushort id = _REV16(Sys.ID[0]);
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ushort seq = _REV16(now);
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icmp->Identifier = id;
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icmp->Sequence = seq;
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icmp->Checksum = 0;
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icmp->Checksum = _REV16(Tip->CheckSum(&ip, (byte*)icmp, sizeof(ICMP_HEADER) + payloadLength, 0));
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#if NET_DEBUG
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debug_printf("ICMP::Ping ");
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ip.Show();
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debug_printf(" with Identifier=0x%04x Sequence=0x%04x", id, seq);
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TimeCost ct;
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#endif
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Tip->SendIP(IP_ICMP, ip, (byte*)icmp, sizeof(ICMP_HEADER) + payloadLength);
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PingSession ps(ip, id, seq);
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_IcmpSession = &ps;
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// 等待响应
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bool rs = ps.Handle.WaitOne(1000);
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#if NET_DEBUG
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uint cost = ct.Elapsed() / 1000;
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if(rs)
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debug_printf(" 成功 %dms\r\n", cost);
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else
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debug_printf(" 失败 %dms\r\n", cost);
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#endif
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return false;
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}
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