1 netAddressBits ourIPAddress(UsageEnvironment& env) {  2   static netAddressBits ourAddress = 0;  3   int sock = -1;  4   struct in_addr testAddr;  5   6   if (ReceivingInterfaceAddr != INADDR_ANY) {  7     // Hack: If we were told to receive on a specific interface address, then   8     // define this to be our ip address:  9     ourAddress = ReceivingInterfaceAddr; 10   } 11  12   if (ourAddress == 0) { 13     // We need to find our source address 14     struct sockaddr_in fromAddr; 15     fromAddr.sin_addr.s_addr = 0; 16  17     // Get our address by sending a (0-TTL) multicast packet, 18     // receiving it, and looking at the source address used. 19     // (This is kinda bogus, but it provides the best guarantee 20     // that other nodes will think our address is the same as we do.) 21     do { 22       loopbackWorks = 0; // until we learn otherwise 23  24       testAddr.s_addr = our_inet_addr("228.67.43.91"); // arbitrary 25       Port testPort(15947); // ditto 26  27       sock = setupDatagramSocket(env, testPort); 28       if (sock < 0) break; 29  30       if (!socketJoinGroup(env, sock, testAddr.s_addr)) break; 31  32       unsigned char testString[] = "hostIdTest"; 33       unsigned testStringLength = sizeof testString; 34  35       if (!writeSocket(env, sock, testAddr, testPort, 0, 36                testString, testStringLength)) break; 37  38       // Block until the socket is readable (with a 5-second timeout): 39       fd_set rd_set; 40       FD_ZERO(&rd_set); 41       FD_SET((unsigned)sock, &rd_set); 42       const unsigned numFds = sock+1; 43       struct timeval timeout; 44       timeout.tv_sec = 5; 45       timeout.tv_usec = 0; 46       int result = select(numFds, &rd_set, NULL, NULL, &timeout); 47       if (result <= 0) break; 48  49       unsigned char readBuffer[20]; 50       int bytesRead = readSocket(env, sock, 51                  readBuffer, sizeof readBuffer, 52                  fromAddr); 53       if (bytesRead != (int)testStringLength 54       || strncmp((char*)readBuffer, (char*)testString, testStringLength) != 0) { 55     break; 56       } 57  58       // We use this packet‘s source address, if it‘s good: 59       loopbackWorks = !badAddressForUs(fromAddr.sin_addr.s_addr); 60     } while (0); 61  62     if (sock >= 0) { 63       socketLeaveGroup(env, sock, testAddr.s_addr); 64       closeSocket(sock); 65     } 66  67     if (!loopbackWorks) do { 68       // We couldn‘t find our address using multicast loopback, 69       // so try instead to look it up directly - by first getting our host name, and then resolving this host name 70       char hostname[100]; 71       hostname[0] = ‘\0‘; 72       int result = gethostname(hostname, sizeof hostname); 73       if (result != 0 || hostname[0] == ‘\0‘) { 74     env.setResultErrMsg("initial gethostname() failed"); 75     break; 76       } 77  78       // Try to resolve "hostname" to an IP address: 79       NetAddressList addresses(hostname); 80       NetAddressList::Iterator iter(addresses); 81       NetAddress const* address; 82  83       // Take the first address that‘s not bad: 84       netAddressBits addr = 0; 85       while ((address = iter.nextAddress()) != NULL) { 86     netAddressBits a = *(netAddressBits*)(address->data()); 87     if (!badAddressForUs(a)) { 88       addr = a; 89       break; 90     } 91       } 92  93       // Assign the address that we found to "fromAddr" (as if the ‘loopback‘ method had worked), to simplify the code below:  94       fromAddr.sin_addr.s_addr = addr; 95     } while (0); 96  97     // Make sure we have a good address: 98     netAddressBits from = fromAddr.sin_addr.s_addr; 99     if (badAddressForUs(from)) {100       char tmp[100];101       sprintf(tmp, "This computer has an invalid IP address: %s", AddressString(from).val());102       env.setResultMsg(tmp);103       from = 0;104     }105 106     ourAddress = from;107 108     // Use our newly-discovered IP address, and the current time,109     // to initialize the random number generator‘s seed:110     struct timeval timeNow;111     gettimeofday(&timeNow, NULL);112     unsigned seed = ourAddress^timeNow.tv_sec^timeNow.tv_usec;113     our_srandom(seed);114   }115   return ourAddress;116 }

ifconfig eth0|grep ‘inet addr‘|awk -F ":" ‘{print $2}‘|awk ‘{print $1}‘

    // Make sure we have a good address:    netAddressBits from = fromAddr.sin_addr.s_addr;

 1     if (badAddressForUs(fromAddr.sin_addr.s_addr)) 2     { 3         #define MY_IP_BUF_LEN 32 4         char MyIpBuf[ MY_IP_BUF_LEN ]={0}; 5         FILE *fpRead; 6         //eth0:网口名称，实际主机的网口名称可能不是这个，请使用ifconfig命令查看。 7         char* command=(char*)"ifconfig eth0|grep ‘inet addr‘|awk -F \":\" ‘{print $2}‘|awk ‘{print $1}‘"; 8         char* renewCh; 9         10         fpRead = popen(command, "r");11         fgets(MyIpBuf, MY_IP_BUF_LEN, fpRead);12         if(fpRead != NULL)13             pclose(fpRead);14 15         renewCh=strstr(MyIpBuf,"\r");16         if(renewCh)17             *renewCh=‘\0‘;18         renewCh=strstr(MyIpBuf,"\n");19         if(renewCh)20             *renewCh=‘\0‘;21             22         fromAddr.sin_addr.s_addr=our_inet_addr(MyIpBuf);23         printf("----------fix for geting local ip fails, local ip=%s.\n", MyIpBuf);24     }