Socket raw for C network programming in Linux

Simulate Ping

// ================================================ ==================================================================== // Name: raw_myping.cpp // Author: gaotong // version: // copyright: Your copyright notice/Description: Hello world in C ++, ANSI-style // ========================================== ========================================================== = # include <stdio. h> # include <sys/types. h> # include <sys/socket. h> # include <netdb. h> # include <netinet/in. h> # In Clude <netinet/in_sy2.16.h> # include <netinet/IP. h> # include <netinet/ip_icmp.h> # include <string. h> # include <stdlib. h> # include <ARPA/inet. h> # include <unistd. h> int main (INT argc, char * argv []) {int S, I; char Buf [400]; struct IP * IP = (struct IP *) BUF; struct icmphdr * ICMP = (struct icmphdr *) (IP + 1); struct hostent * HP, * Hp2; struct sockaddr_in DST; int offset; int on; int num = 100; if (argc <3) {printf ("\ Nusage: % S <saddress> <dstaddress> [number] \ n ", argv [0]); printf ("-saddress is the spoofed source address \ n "); printf ("-dstaddress is the target \ n"); printf ("-number is the number of packets to send, 100 is the default \ n "); exit (1);}/* If the input parameter meets the requirements */If (argc = 4) /* assign a value to the number of sent packets */num = atoi (argv [3]);/* Loop Based on the packet number */for (I = 1; I <= num; I ++) {printf ("test \ n"); On = 1; bzero (BUF, siz EOF (BUF);/* Create raw socket */If (S = socket (af_inet, sock_raw, ipproto_raw) <0) {perror ("socket () error ");/* If something wrong, just exit */exit (1);}/* Use SOCKET options to inform the system of IP structure * // prototype: int setsockopt (INT socket, int level, int optname, void * optval, socklen_t optlen) if (setsockopt (S, ipproto_ip, ip_hdrincl, & on, sizeof (on) <0) {perror ("setsockopt () for ip_hdrincl Error "); Exit (1);}/* gethostbyname () returns the hostent structure pointer that corresponds to the Host Name and address information of the given host name. */If (HP = gethostbyname (argv [2]) = NULL) {If (IP-> ip_dst.s_addr = inet_addr (argv [2]) =-1) {fprintf (stderr, "% s: can't resolve, unknown host. \ n ", argv [2]); exit (1) ;}} elsebcopy (HP-> h_addr_list [0], & IP-> ip_dst.s_addr, HP-> h_length ); /* the following source address just redundant for target to collect */If (Hp2 = gethostbyname (argv [1]) = NULL) {If (IP-> ip_src.s_addr = inet_addr (argv [1]) = -1) {fprintf (stderr, "% s: can't resolve, unknown host \ n", argv [1]); exit (1 );}} elsebcopy (Hp2-> h_addr_list [0], & IP-> ip_src.s_addr, HP-> h_length); printf ("sending to % s from spoofed % s \ n ", inet_ntoa (IP-> ip_dst), argv [1]);/* IP structure, check the IP. H */IP-> ip_v = 4; IP-> ip_hl = sizeof * ip> 2; IP-> ip_tos = 0; IP-> ip_len = htons (sizeof (BUF); IP-> ip_id = htons (4321); IP-> ip_off = htons (0); IP-> ip_ttl = 255; I P-> ip_p = 1; IP-> ip_sum = 0;/* Let kernel fills in */DST. sin_addr = IP-> ip_dst; DST. sin_family = af_inet; ICMP-> type = ICMP_Echo; ICMP-> code = 0;/* Header checksum */ICMP-> checksum = htons (~ (ICMP_Echo <8); // For (offset = 0; offset <65536; offset + = (sizeof (BUF)-sizeof (* IP ))) // {IP-> ip_off = htons (Offset> 3); If (offset <65120) IP-> ip_off | = htons (0x2000 ); elseip-> ip_len = htons (418);/* make total 65538 * // * sending time */If (sendto (S, Buf, sizeof (BUF), 0, (struct sockaddr *) & DST, sizeof (DST) <0) {fprintf (stderr, "offset % d:", offset); perror ("sendto () error ");} elseprintf (" sendto () is OK. \ n ");/* If offset = 0, define our ICMP structure */If (offset = 0) {ICMP-> type = 0; ICMP-> code = 0; ICMP-> checksum = 0;} //}/* close socket */close (s); usleep (30000);} return 0 ;}