nat p2p udp穿墙打洞源码

#include "proto.h" #include <iostream> #include <sys/socket.h> #include <arpa/inet.h> #include <netinet/in.h> #include <unistd.h> #include <cstring> int _7777_sock; // bind监听端口 ClientsList _7777_clientsList; void send_to(int sock, const char *destIP, const int destPort, stMessage *sendbuf) { struct sockaddr_in server_addr{}; memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_addr.s_addr = inet_addr(destIP); server_addr.sin_port = htons(destPort); for (int i = 0; i < 10; i++) { sendto(sock, sendbuf, sizeof(*sendbuf), 0, (const sockaddr *) &server_addr, sizeof(server_addr)); usleep(50);// UDP不可靠，故而等待一会 等待对方先发送信息 } } void *recvThread7777(void *p) { ST1 *stp = (ST1 *) p; ST1 st; st.sock = stp->sock; st.sock_addr = stp->sock_addr; delete stp; stMessage recvbuf{}; while (true) { memset(&recvbuf, 0, sizeof(stMessage)); /* UDP */ struct sockaddr_in clientAddr{}; /*本地地址*/ uint32_t addr_len = sizeof(clientAddr); int ret = recvfrom(st.sock, (char *) &recvbuf, sizeof(stMessage), 0, (struct sockaddr *) &clientAddr, &addr_len); if (ret == -1) { printf("recvfrom %s(%d)\n", strerror(errno), errno); pthread_exit((void *) 1); } else { int messageType = recvbuf.iMessageType; switch (messageType) { case LOGIN: // 这case是B要作的事情 // A让你B打洞 { /*S存上经过NAT-A,NAT-B网关映射转换了的A和B的公网IP和端口号*/ /* client's IP，Port*/ printf("来人了：%s:%d \n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port)); auto *pClient = new stClient(); pClient->client_addr = clientAddr; strcpy(pClient->userName, recvbuf.userName); /* 查找有无次用户名，有则更新，无则插入 */ int clientsCount = (int) _7777_clientsList.size(); // 总客户端数量 if (clientsCount == 0) { _7777_clientsList.push_back(pClient); // 插入 } else { for (auto UserIterator = _7777_clientsList.begin(); UserIterator != _7777_clientsList.end(); ++UserIterator) { if (strcmp(((*UserIterator)->userName), pClient->userName) == 0) // 找到了 { /* 更新 */ (*UserIterator)->client_addr = pClient->client_addr; break; } else //没找到 { _7777_clientsList.push_back(pClient); // 插入 } } } for (auto UserIterator = _7777_clientsList.begin(); UserIterator != _7777_clientsList.end(); ++UserIterator) // 发送每个客户端的公网ip,port { printf("%s\n", (*UserIterator)->userName); } break; } case P2PTRANS: // 6、S sendto A：【P2PTRANS2】+B经过NAT-B转换后的公网IP地址和映射端口 { const char *clientBusername = recvbuf.szMessage; /* 查找用户名B */ sockaddr_in clientBAddr{}; for (auto UserIterator = _7777_clientsList.begin(); UserIterator != _7777_clientsList.end(); ++UserIterator) { if (strcmp(((*UserIterator)->userName), clientBusername) == 0) // 找到了 { clientBAddr = (*UserIterator)->client_addr; break; } } stMessage sendbuff; sendbuff.iMessageType = P2PTRANS2; strcpy(sendbuff.userName, recvbuf.userName); // B's name if (clientBAddr.sin_addr.s_addr == 0) { strcpy(sendbuff.szMessage, "no this ip"); } else { char clientBIPandPort[IPANDPORTLen] = ""; memset(clientBIPandPort, 0, IPANDPORTLen); sprintf(clientBIPandPort, "%s:%d", inet_ntoa(clientBAddr.sin_addr), ntohs(clientBAddr.sin_port)); strcpy(sendbuff.szMessage, clientBIPandPort); // B's IP:port } /* client's IP，Port inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port)); */ /* UDP */ int sock = socket(AF_INET, SOCK_DGRAM, 0); /*建立套接字*/ if (sock == -1) { printf("socket %s(%d)\n", strerror(errno), errno); pthread_exit((void *) 1); } send_to(sock, inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port), &sendbuff); break; } case P2PSOMEONEWANTTOCALLYOU: // 10、S sendto B：【P2PSOMEONEWANTTOCALLYOU】+A的username+A的公网IP端口 { const char *clientAusername = recvbuf.userName; /* 查找用户名B */ sockaddr_in clientAAddr{}; for (auto UserIterator = _7777_clientsList.begin(); UserIterator != _7777_clientsList.end(); ++UserIterator) { if (strcmp(((*UserIterator)->userName), clientAusername) == 0) // 找到了 { clientAAddr = (*UserIterator)->client_addr; break; } } char clientAIPandPort[IPANDPORTLen] = ""; memset(clientAIPandPort, 0, IPANDPORTLen); sprintf(clientAIPandPort, "%s:%d", inet_ntoa(clientAAddr.sin_addr), ntohs(clientAAddr.sin_port)); stMessage sendbuff; sendbuff.iMessageType = P2PSOMEONEWANTTOCALLYOU; strcpy(sendbuff.userName, clientAusername); // A's name strcpy(sendbuff.szMessage, clientAIPandPort); // A's IP:port sendbuff.iStringLen = strlen(sendbuff.szMessage) + 1; // +1 == /0 /* client's IP，Port inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port)); */ /* UDP */ int sock = socket(AF_INET, SOCK_DGRAM, 0); /*建立套接字*/ if (sock == -1) { printf("socket %s(%d)\n", strerror(errno), errno); pthread_exit((void *) 1); } send_to(sock, inet_ntoa(clientAAddr.sin_addr), ntohs(clientAAddr.sin_port), &sendbuff); break; } } } } } int listen_sock(int port) { int sock = socket(AF_INET, SOCK_DGRAM, 0); /*建立套接字*/ if (sock == -1) { printf("socket %s(%d)\n", strerror(errno), errno); return sock; } int opt = 1; if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1)// 快速关闭端口，加快程序重启速度 { printf("SO_REUSEADDR %s(%d)\n", strerror(errno), errno); return -1; } if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) == -1) { printf("SO_REUSEADDR %s(