Цитата(Alexey68 @ 28.7.2015, 08:32  ) | | это обязательное требование? |
Для TCP - да. Для UDP - нет.
Заметил, что у Вас, не смотря на всестороннее описание TCP заголовка, в IP-заголовке внезапно прописывается| Цитата(Alexey68 @ 27.7.2015, 17:06 ) | | v4hdr->ip_protocol = IPPROTO_UDP; |
| Цитата(Alexey68 @ 28.7.2015, 08:32 ) | | искал минимальный пример отправки пакета, но кроме этого не нашёл |
Ну, тогда держите для UDP:| Код | #include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#define MESSAGE "***+++---***0"
void printError( const char *header )
{
LPVOID msgBuf = NULL;
if( FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
NULL, WSAGetLastError(), MAKELANGID( LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &msgBuf, 0, NULL) == 0 )
printf( "Error in %s(), error code %u\n", header, WSAGetLastError());
else
{
CharToOem( (char *) msgBuf, (char *) msgBuf);
printf( "%s: %s\n", header, (char *) msgBuf);
}
LocalFree( msgBuf );
}
unsigned long allsum( unsigned long sum, unsigned short *buffer, int size)
{
while( size >= sizeof(unsigned short) )
{
sum += *buffer++;
size -= sizeof(unsigned short);
}
if( size ) sum += *(unsigned char *) buffer;
return sum;
}
unsigned short checksum( unsigned long sum, unsigned short *buffer, int size)
{
sum = allsum( sum, buffer, size);
sum = (sum >> 16) + (sum & 0xffff);
sum += sum >> 16;
return (unsigned short) (~sum);
}
typedef struct ip_hdr
{
unsigned char ip_verlen;
unsigned char ip_tos;
unsigned short ip_total_len;
unsigned short ip_id;
unsigned short ip_offset;
unsigned char ip_ttl;
unsigned char ip_protocol;
unsigned short ip_checksum;
unsigned int ip_source;
unsigned int ip_dest;
} IP_HDR;
typedef struct udp_hdr
{
unsigned short udp_src_port;
unsigned short udp_dst_port;
unsigned short udp_len;
unsigned short udp_sum;
} UDP_HDR;
int main()
{
WSADATA wsaData;
SOCKET sock = INVALID_SOCKET;
int opt = 1;
if( WSAStartup( 0x0202, &wsaData) )
printError( "WSAStartup" );
else if( (sock = WSASocket( AF_INET, SOCK_RAW, IPPROTO_UDP, NULL, 0, 0)) == INVALID_SOCKET )
printError( "WSASocket" );
else if( setsockopt( sock, IPPROTO_IP, IP_HDRINCL, (char *) &opt, sizeof(opt)) == SOCKET_ERROR )
printError( "setsockopt" );
else
{
char buf[1024];
IP_HDR *ipHdr = (IP_HDR *) buf;
UDP_HDR *udpHdr = (UDP_HDR *) &ipHdr[1];
char *message = (char *) &udpHdr[1];
unsigned short mSize = sizeof(MESSAGE)-1;
unsigned short udpSize = sizeof(*udpHdr) + mSize;
unsigned short totalSize = sizeof(*ipHdr) + udpSize;
struct sockaddr_in remote;
unsigned long sum = 0;
unsigned char tmp[2];
ipHdr->ip_verlen = (4 << 4) | 5;
ipHdr->ip_tos = 0;
ipHdr->ip_total_len = htons( totalSize );
ipHdr->ip_id = 0;
ipHdr->ip_offset = 0;
ipHdr->ip_ttl = 128;
ipHdr->ip_protocol = IPPROTO_UDP;
ipHdr->ip_checksum = 0;
ipHdr->ip_source = inet_addr( "192.168.1.2" );
ipHdr->ip_dest = inet_addr( "192.168.1.1" );
udpHdr->udp_src_port = htons( 30000 );
udpHdr->udp_dst_port = htons( 30000 );
udpHdr->udp_len = htons( udpSize );
udpHdr->udp_sum = 0;
memcpy( message, MESSAGE, mSize);
sum = allsum( sum, (unsigned short *) &ipHdr->ip_source, sizeof(ipHdr->ip_source));
sum = allsum( sum, (unsigned short *) &ipHdr->ip_dest, sizeof(ipHdr->ip_dest));
tmp[0] = 0;
tmp[1] = ipHdr->ip_protocol;
sum = allsum( sum, (unsigned short *) tmp, sizeof(tmp));
sum = allsum( sum, (unsigned short *) &udpHdr->udp_len, sizeof(udpHdr->udp_len));
sum = allsum( sum, (unsigned short *) udpHdr, sizeof(*udpHdr));
udpHdr->udp_sum = checksum( sum, (unsigned short *) message, mSize);
remote.sin_family = AF_INET;
remote.sin_port = udpHdr->udp_dst_port;
remote.sin_addr.s_addr = ipHdr->ip_dest;
if( sendto( sock, buf, totalSize, 0, (struct sockaddr *) &remote, sizeof(remote)) == SOCKET_ERROR )
printError( "sendto" );
else
printf( "Successful sendto()\n" );
}
if( sock != INVALID_SOCKET && closesocket( sock ) == SOCKET_ERROR )
printError( "closesocket" );
if( WSACleanup() ) printError( "WSACleanup" );
return 0;
} |
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