[root@TD18 tmp]#gcc -o 1 1.c -lnet [root@TD18 tmp]#./1 please enter Host address 11.11.11.11 please enter local address: 22.22.22.22 wrote 126 byte TCP packet [root@TD18 tmp]#cat 1.c #include<stdio.h> #include<string.h> #include<pcap.h> #include<libnet.h> main(void) { int c ; u_char *cp; libnet_t *l; libnet_ptag_t t; char *payload; u_char HostAddr[255],MyAddr[255]; u_short payload_s; u_long src_ip,dst_ip; u_short src_prt,dst_prt; char errbuf[LIBNET_ERRBUF_SIZE]; printf("please enter Host address "); scanf("%s",HostAddr); printf("please enter local address: "); scanf("%s",MyAddr); l=libnet_init( LIBNET_LINK,NULL,errbuf); if(l==NULL) { printf("libnet failed: %s",errbuf); exit(EXIT_FAILURE); } dst_ip=inet_addr(HostAddr); src_ip=inet_addr(MyAddr); dst_prt=0; src_prt=0; payload="adafhafhasfjashfasjfasjkfhsadjkfajskfjasdhfjaksfjkaf"; payload_s=strlen(payload); t=libnet_build_tcp_options("