Вот такой получается код:
#include <vcl.h>
#include <winsock2.h> #include <ws2tcpip.h>
#include <stdio.h> #include <stdlib.h> #pragma hdrstop
#pragma pack(1)
#define WIN32_LEAN_AND_MEAN
#include "Unit1.h"
//---------------------------------------------------------- -----------------
#pragma package(smart_init)
#pragma resource "*.dfm"
#define MAX_MESSAGE 4068
#define MAX_PACKET 4096
#define DEFAULT_MESSAGE "This is a test"
struct tcpheader
{
unsigned short int th_sport;
unsigned short int th_dport;
unsigned int th_seq;
unsigned int th_ack;
unsigned char th_x2:4, th_off:4;
unsigned char th_flags;
unsigned short int th_win;
unsigned short int th_sum;
unsigned short int th_urp;
unsigned char identity [4];
unsigned char data [200];
} ; /* total tcp header length: 20 bytes (=160 bits) */
struct ipheader {
unsigned char ip_hl:4, ip_v:4; /* this means that each member is 4 bits */
unsigned char ip_tos;
unsigned short int ip_len;
unsigned short int ip_id;
unsigned short int ip_off;
unsigned char ip_ttl;
unsigned char ip_p;
unsigned short int ip_sum;
unsigned int ip_src;
unsigned int ip_dst;
}; /* total ip header length: 20 bytes (=160 bits) */
typedef struct ps_hdr
{
unsigned int source_address; // Source Address ; ; ; => 4 Bytes
unsigned int dest_address; &n bsp;// Destination Address => 4 Bytes
unsigned char placeholder; &n bsp; // Place Holder & nbsp; => &n bsp; & nbsp;1 Bytes
unsigned char protocol; ; ; &nb sp; // Protocol &nbs p; => 1 Bytes
unsigned short tcp_length; & nbsp; // TCP Length &nb sp; => &nbs p; + 2 Bytes
// &nbs p; &nbs p; &nbs p; &nbs p; = 12 Bytes
struct tcpheader tcp;
}PS_HDR;
char &n bsp; strMessage[MAX_MESSAGE]; // Message to send
TForm1 *Form1;
//---------------------------------------------------------- -----------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------- -----------------
USHORT checksum(USHORT *buffer, int size)
{
unsigned long cksum=0;
while (size > 1)
{
cksum += *buffer++;
size -= sizeof(USHORT);
}
if (size)
{
cksum += *(UCHAR*)buffer;
}
cksum = (cksum >> 16) + (cksum & 0xffff);
cksum += (cksum >>16);
return (USHORT)(~cksum);
}
void __fastcall TForm1::Button1Click(TObject *Sender)
{
WSADATA ; ; wsd;
SOCKET s;
DWORD & nbsp; i;
char &n bsp; *datagram="", ident[] = "ScMX";
hostent ; *h = NULL;
int &nb sp; bOpt = 1, y, len;
char &n bsp; RecvBuf [200];
struct ipheader *iph = (struct ipheader *) malloc(sizeof(struct ipheader));
struct tcpheader *tcph = (struct tcpheader *) malloc( sizeof (struct tcpheader));
struct ps_hdr *ps = (struct ps_hdr *) malloc( sizeof (struct ps_hdr));
datagram = (char *) malloc(sizeof(struct ipheader) + sizeof(struct tcpheader));
struct sockaddr_in sin, dest;
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
ShowMessage("WSAStartup() failed: " + IntToStr(GetLastError()));
return;
}
s = WSASocket(AF_INET, SOCK_RAW, IPPROTO_RAW, NULL, 0,0);
if (s == INVALID_SOCKET)
{
ShowMessage("WSASocket failed: " + IntToStr(GetLastError()));
return;
}
iph= (struct ipheader *) datagram;
tcph=(struct tcpheader *) (datagram+ sizeof(struct ipheader));
sin.sin_family = AF_INET;
sin.sin_port = htons (110);
h = gethostbyname("localhost");
if(h == NULL)
ShowMessage("╬°шсър gethostbyname");
sin.sin_addr.s_addr = inet_addr (inet_ntoa(*((struct in_addr *)h->h_addr)));
iph->ip_hl = 5;
iph->ip_v = 4;
iph->ip_tos = 0;
iph->ip_len = sizeof (struct ipheader) + sizeof (struct tcpheader);
iph->ip_id = 1;
iph->ip_off = 0;
iph->ip_ttl = 255;
iph->ip_p = IPPROTO_TCP;
iph->ip_sum = 0;
iph->ip_src = inet_addr ("127.0.0.1");
iph->ip_dst = sin.sin_addr.s_addr;
tcph->th_sport = htons (1999);
tcph->th_dport = htons (135);
tcph->th_seq = 666;
tcph->th_ack = htons (6234);
tcph->th_x2 = 0;
tcph->th_off = 5;
tcph->th_flags = 16; // SYN
tcph->th_win = htons(65535);
tcph->th_sum = 0;
tcph->th_urp = 0;
strncpy((char *)tcph->identity,ident,4);
for(i = 0; i < strlen(strMessage); i++)
tcph->data[I]=strMessage[I];
ps->source_address &nb sp;= inet_addr ("127.0.0.1");
ps->dest_address = sin.sin_addr.s_addr;
ps->placeholder = 0;
ps->protocol = IPPROTO_TCP;
ps->tcp_length = htons(sizeof(struct tcpheader));
ps->tcp = *tcph;
tcph->th_sum = checksum((unsigned short *)ps, sizeof(struct ps_hdr));
iph->ip_sum = checksum((unsigned short *)iph, sizeof(struct ipheader));
setsockopt(s, IPPROTO_IP, IP_HDRINCL, (char *)&bOpt, sizeof(bOpt));
if (sendto(s, datagram, iph->ip_len, 0, (SOCKADDR *)&sin, sizeof(sin)) == SOCKET_ERROR)
{
ShowMessage("sendto() failed: " + IntToStr(WSAGetLastError()));
return;
}
memset(datagram,0,strlen (datag ram));
i = 0;
len = sizeof(sin);
i = recvfrom(s, RecvBuf, 200, 0,(sockaddr*)&sin, &len);
if(i > 0)
RichEdit1->Line s-> Add("& #9575;юыєўхэ яръхЄ.");
/*while(i < 1)
{
memset(RecvBuf, 0, sizeof(RecvBuf));
i = recv(s, RecvBuf, 200, 0);
}
RichEdit1->Lines-> Add("& #9575; юыєўхэ яръхЄ."); */
closesocket(s) ;
WSACleanup() ;
}
//---------------------------------------------------------- -----------------
Никак не могу понять почему в ответ не приходит вообще никакого пакета (recivefrom), когда, по идее, должен прийти пакет с флагом ask.
Очень буду признателе за помощь.
Цель: получить tcp - пакет от удалённой машины, дабы в дальнейшем из tcp-заголовка достать размер окна....
Единственно, есть некототые сомнения, что 16 устанавливае SYN-флаг (это получается 00010000), а, если я не ошибаюсь,то SYN-флагу будет соответствовать 00000010, т.е. 2. Но замена 16 на два ровным счётом ничего не решает.
В чём может быть дело?
