제가 조금 개조해 봤네요
쓸만 해요 ^^
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/ip_icmp.h>
#include <netdb.h>
unsigned short ip_cksum(unsigned char * buff, int len)
{
unsigned long sum = 0;
if (len > 3)
{
__asm__("clc\n"
"1:\t"
"lodsl\n\t"
"adcl %%eax, %%ebx\n\t"
"loop 1b\n\t"
"adcl $0, %%ebx\n\t"
"movl %%ebx, %%eax\n\t"
"shrl $16, %%eax\n\t"
"addw %%ax, %%bx\n\t"
"adcw $0, %%bx"
: "=b" (sum) , "=S" (buff)
: "0" (sum), "c" (len >> 2) ,"1" (buff)
: "ax", "cx", "si", "bx" );
}
if (len & 2)
{
__asm__("lodsw\n\t"
"addw %%ax, %%bx\n\t"
"adcw $0, %%bx"
: "=b" (sum), "=S" (buff)
: "0" (sum), "1" (buff)
: "bx", "ax", "si");
}
if (len & 1)
{
__asm__("lodsb\n\t"
"movb $0, %%ah\n\t"
"addw %%ax, %%bx\n\t"
"adcw $0, %%bx"
: "=b" (sum), "=S" (buff)
: "0" (sum), "1" (buff)
: "bx", "ax", "si");
}
sum =~sum;
return(sum & 0xffff);
}
unsigned short tcp_check(struct tcphdr *th, int len,
unsigned long saddr, unsigned long daddr)
{
unsigned long sum;
__asm__("
addl %%ecx, %%ebx
adcl %%edx, %%ebx
adcl $0, %%ebx
"
: "=b"(sum)
: "0"(daddr), "c"(saddr), "d"((ntohs(len) << 16) + IPPROTO_TCP*256)
: "bx", "cx", "dx" );
__asm__("
movl %%ecx, %%edx
cld
cmpl $32, %%ecx
jb 2f
shrl $5, %%ecx
clc
1: lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
lodsl
adcl %%eax, %%ebx
loop 1b
adcl $0, %%ebx
movl %%edx, %%ecx
2: andl $28, %%ecx
je 4f
shrl $2, %%ecx
clc
3: lodsl
adcl %%eax, %%ebx
loop 3b
adcl $0, %%ebx
4: movl $0, %%eax
testw $2, %%dx
je 5f
lodsw
addl %%eax, %%ebx
adcl $0, %%ebx
movw $0, %%ax
5: test $1, %%edx
je 6f
lodsb
addl %%eax, %%ebx
adcl $0, %%ebx
6: movl %%ebx, %%eax
shrl $16, %%eax
addw %%ax, %%bx
adcw $0, %%bx
"
: "=b"(sum)
: "0"(sum), "c"(len), "S"(th)
: "ax", "bx", "cx", "dx", "si" );
/* We only want the bottom 16 bits, but we never cleared the top 16. */
return((~sum) & 0xffff);
}
void resolve_address(struct sockaddr *addr, char *hostname, u_short port) {
struct sockaddr_in *address;
struct hostent *host;
address = (struct sockaddr_in *)addr;
(void) bzero((char *)address, sizeof(struct sockaddr_in));
address->sin_family = AF_INET;
address->sin_port = htons(port);
address->sin_addr.s_addr = inet_addr(hostname);
if ((int)address->sin_addr.s_addr == -1) {
host = gethostbyname(hostname);
if (host) {
bcopy( host->h_addr, (char *)&address->sin_addr, host->h_length);
}
else {
puts("Couldn't resolve address!!!");
exit(-1);
}
}
}
char *create_ip(u_long source, u_long dest, u_char protocol, u_char ttl,
u_short id, char *data, int data_len)
{
char *ip_datagram;
struct iphdr *ip_header;
ip_datagram = malloc(sizeof(struct iphdr) + data_len);
ip_header = ip_datagram;
ip_header->version = 4;
ip_header->tos = 0;
ip_header->frag_off = 0;
ip_header->check = 0;
ip_header->saddr = source;
ip_header->daddr = dest;
ip_header->protocol = protocol;
ip_header->ttl = ttl;
ip_header->id = htons(id);
ip_header->ihl = 5;
ip_header->tot_len = htons(sizeof(struct iphdr) + data_len);
ip_header->check = htons(ip_cksum(ip_datagram,sizeof(struct iphdr)));
bcopy(data,ip_datagram+sizeof(struct iphdr),data_len);
return ip_datagram;
}
char *create_tcp(u_long source, u_long dest, u_short sport, u_short dport,
u_long seqnum, u_long acknum, u_char flags, char *data, int datalen)
{
char *wewt;
struct tcphdr *tcp_header;
wewt = malloc(sizeof(struct tcphdr) + datalen);
tcp_header = wewt;
tcp_header->th_sport = sport;
tcp_header->th_dport = dport;
tcp_header->th_seq = seqnum;
tcp_header->th_ack = acknum;
tcp_header->th_flags = flags;
tcp_header->th_sum = 0;
tcp_header->th_sum = htons(tcp_check(tcp_header, sizeof(struct tcphdr),
source, dest));
bcopy(data,wewt+sizeof(struct tcphdr),datalen);
return wewt;
}
void sendpack(char *fromhost, int fromport, char *tohost, int toport) {
char *packet;
char *tcppacket;
char *sendme;
static struct sockaddr_in local, remote;
static int sock = 0;
if (!sock) {
resolve_address((struct sockaddr *)&local, fromhost, fromport);
resolve_address((struct sockaddr *)&remote, tohost, toport);
sock = socket(AF_INET, SOCK_RAW, 255);
if (sock == -1) { perror("Getting raw socket"); exit(-1); }
}
tcppacket = create_tcp(&local.sin_addr, &remote.sin_addr,
local.sin_port, remote.sin_port, 795930600, 0, TH_SYN,
NULL, 0);
packet = create_ip(&local.sin_addr, &remote.sin_addr,
6, 24, 4, NULL, 0);
sendme = (struct iphdr *)packet;
bcopy(tcppacket, sendme+sizeof(struct iphdr), sizeof(tcppacket));
printf("the ip header is %d bytes long.\n", sizeof(struct iphdr));
printf("the tcp header is %d bytes long.\n", sizeof(struct tcphdr));
printf("the ip packet is %d bytes long.\n", sizeof(packet));
printf("the tcp packet is %d bytes long.\n", sizeof(tcppacket));
printf("the final packet is %d bytes long.\n", sizeof(sendme));
{
int result;
result = sendto(sock, packet, sizeof(packet), 0,
(struct sockaddr *)&remote, sizeof(remote));
if (result != sizeof(packet)) { perror("sending packet"); }
}
}
main(int argc, char **argv) {
if (argc!=5) {
printf("usage: %s <from host> <from port> <to host> <to port>\n", argv[0]);
exit(-1);
}
printf("forging packet from %s.%d to %s.%d\n", argv[1], atoi(argv[2]),
argv[3], atoi(argv[4]));
sendpack(argv[1], atoi(argv[2]), argv[3], atoi(argv[4]));
}
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1586, 
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