/* fcntl */ int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen) { int ret; struct sock *sk; socket_idesc_check(sockfd, sk); if ((addr == NULL) || (addrlen == NULL) || (*addrlen <= 0)) { return SET_ERRNO(EINVAL); } ret = kgetpeername(sk, addr, addrlen); if (ret < 0){ return SET_ERRNO(-ret); } return 0; }
/*this handles the redirection from client to real server*/ void RedirectProc (ksocket_t SockfdFromClnt) { struct sockaddr_in RealSrvAddr, stRelayAddr, stTemp1, stTemp; ksocket_t SockfdRelay; int on = 1; char frwd_buffer[BUFFER_SIZE]; int iRBytes, iWBytes, iNWritten, cur, iLen; unsigned short iClntPort, server_port = 0; /* kernel thread name*/ sprintf(current->comm, "krelaychld"); allow_signal(SIGKILL); allow_signal(SIGTERM); //Copy the values for later use if ((kgetpeername(SockfdFromClnt, (struct sockaddr *)&stTemp1, &iLen)) < 0) { printk (KERN_ERR "kgetpeername() failed\n"); } iClntPort = stTemp1.sin_port; /*Create socket*/ if ((SockfdRelay = ksocket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) printk(KERN_ERR "Can't create socket."); memset(&stRelayAddr, 0, sizeof(stRelayAddr)); stRelayAddr.sin_family = AF_INET; stRelayAddr.sin_addr.s_addr = INADDR_ANY; stRelayAddr.sin_port = htons(0); if (ksetsockopt(SockfdRelay, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) { printk(KERN_ERR "ksetsockopt(SO_REUSEADDR) failed\n"); } /*Bind our local addrress so that client can send*/ if (kbind(SockfdRelay, (struct sockaddr *) &stRelayAddr, sizeof(stRelayAddr)) < 0) { printk(KERN_ERR "Can't bind local address\n"); return; } //printk (KERN_ERR "Relay eph port= %d", ntohs(stRelayAddr.sin_port)); //Need to analyze this part@@@@@@@@@ //Store the relay server ephemeral port (Y) in NAT if (kgetsockname(SockfdRelay, (struct sockaddr *) &stTemp, &iLen) < 0) { printk(KERN_ERR "kgetpeername failed\n"); } // printk (KERN_ERR "Relay eph port= %d", ntohs(stTemp.sin_port)); for (cur = 0; cur <= MAX_TBL_IDX -1; cur++) { if (stTbl[cur].iClntPort == iClntPort) { stTbl[cur].iRelayPort = stTemp.sin_port; server_port = stTbl[cur].iClntSrvPort; break; } } if (0 == server_port) { printk (KERN_ERR "Error..Cannot get the server port\n"); kclose (SockfdRelay); return; } //Connect to the Real server RealSrvAddr.sin_family = PF_INET; RealSrvAddr.sin_addr.s_addr = (inet_addr(DEF_REAL_IP)); RealSrvAddr.sin_port = server_port; if (kconnect(SockfdRelay, (struct sockaddr *) &RealSrvAddr, sizeof(RealSrvAddr)) < 0) { printk(KERN_ERR "Connect failed\n"); } for (;;) { //printk (KERN_ERR "trying krecv from client\n"); /* Read from Client and send to Real Server */ iRBytes = krecv(SockfdFromClnt, &frwd_buffer, BUFFER_SIZE - 8, MSG_DONTWAIT); //printk (KERN_ERR "tried krecv = %d\n", iRBytes); //Client Socket is closed if (iRBytes == 0) break; iWBytes = 0; iNWritten = 0; //If some data is there to be read while (iWBytes != iRBytes && iRBytes > 0) { if ((iNWritten = ksend(SockfdRelay, &frwd_buffer + iWBytes , iRBytes-iWBytes, 0)) < 0) { printk (KERN_ERR "error occured while writing to receiver\n"); return; } iWBytes += iNWritten; } //printk (KERN_ERR "trying krecv from real server\n"); /* Read from Real server and write to client */ iRBytes = krecv(SockfdRelay, &frwd_buffer, BUFFER_SIZE - 8, MSG_DONTWAIT); //printk (KERN_ERR "tried krecv1 = %d\n", iRBytes); if (iRBytes == 0) break; iWBytes = 0; iNWritten = 0; while (iWBytes != iRBytes && iRBytes > 0) { if ((iNWritten = ksend(SockfdFromClnt, &frwd_buffer + iWBytes , iRBytes-iWBytes, 0)) < 0) { printk (KERN_ERR "error occured while writing to receiver\n"); return; } iWBytes += iNWritten; } //Sleep for sometime // mdelay (1); } (void)kclose(SockfdRelay); (void)kclose(SockfdFromClnt); }