附源程序：
/* * This program demonstrate SOCK_PACK call. * Thanks Linux. Thanks Alan Cox * derived from/usr/src/redhat/SOURCES/dosemu-0.66.7/src/dosext/net/net/libpacket.c * compile method： cc capturer.c -o capturer */ /* * Alan Cox raw code */ /* * SOCK_PACKET support. * Placed under the GNU LGPL. * * First cut at a library of handy support routines. Comments, additions * and bug fixes greatfully received. * * (c) 1994 Alan Cox [email protected] GW4PTS@GB7SWN */ #include #include #include #include #include #include #include #include #include #include #include /*#if __GLIBC__ > 1*/ #include #include /*#else #include #include #endif*/ #include #include /* * Obtain a file handle on a raw ethernet type. In actual fact * you can also request the dummy types for AX.25 or 802.3 also * * -1 indicates an error * 0 or higher is a file descriptor which we have set non blocking * * WARNING: It is ok to listen to a service the system is using (eg arp) * but don't try and run a user mode stack on the same service or all * hell will break loose. */ int OpenNetworkType(unsigned short netid) { int s = socket(AF_INET, SOCK_PACKET, htons(netid)); if (s == -1) return -1; fcntl(s, F_SETFL, O_NDELAY); return s; } /* * Close a file handle to a raw packet type. */ void CloseNetworkLink(int sock) { close(sock); } /* * Write a packet to the network. You have to give a device to * this function. This is a device name (eg 'eth0' for the first * ethernet card). Please don't assume eth0, make it configurable * - plip is ethernet like but not eth0, ditto for the de600's. * * Return: -1 is an error * otherwise bytes written. */ int WriteToNetwork(int sock, const char *device, const char *data, int len) { struct sockaddr sa; sa.sa_family = AF_INET; strcpy(sa.sa_data, device); return (sendto(sock, data, len, 0, &sa, sizeof(sa))); } /* * Read a packet from the network. The device parameter will * be filled in by this routine (make it 32 bytes or more). * If you wish to work with one interface only you must filter * yourself. Remember to make your buffer big enough for your * data. Oversized packets will be truncated. * * Return: * -1 Error * otherwise Size of packet received. */ int ReadFromNetwork(int sock, char *device, char *data, int len) { struct sockaddr sa; int sz = sizeof(sa); int error; error = recvfrom(sock, data, len, 0, &sa, &sz); if (error == -1) return -1; strcpy(device, sa.sa_data); return error; /* Actually size of received packet */ } /* * Handy support routines. */ /* * Obtain the hardware address of an interface. * addr should be a buffer of 8 bytes or more. * * Return: * 0 Success, buffer holds data. * -1 Error. */ /* * NET2 or NET3 - work for both. */ #if defined(OLD_SIOCGIFHWADDR) || (KERNEL_VERSION >= 1003038) #define NET3 #endif int GetDeviceHardwareAddress(char *device, char *addr) { int s = socket(AF_INET, SOCK_DGRAM, 0); struct ifreq req; int err; strcpy(req.ifr_name, device); err = ioctl(s, SIOCGIFHWADDR, &req); close(s); /* Thanks Rob. for noticing this */ if (err == -1) return err; memcpy(addr, req.ifr_hwaddr.sa_data,8); return 0; } /* * Obtain the maximum packet size on an interface. * * Return: * >0 Return is the mtu of the interface * -1 Error. */ int GetDeviceMTU(char *device) { int s = socket(AF_INET, SOCK_DGRAM, 0); struct ifreq req; int err; strcpy(req.ifr_name, device); err = ioctl(s, SIOCGIFMTU, &req); close(s); /* So I'll add this one as well. Ok Alan? - Rob */ if (err == -1) return err; return req.ifr_mtu; } #define data_packet_len 1514 int main(int argc ,char *argv[]) { char devicename_rec[32]; unsigned char data[data_packet_len]; int netid=0x03,sock_h=0,i=0,count_rec=0; if ((sock_h=OpenNetworkType(netid))0) { printf("Received Packet = %d\n",++count_rec) ; for (i=0;i