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hping2

    1: /* 
    2:  * $smu-mark$ 
    3:  * $name: sendtcp.c$ 
    4:  * $author: Salvatore Sanfilippo <antirez@invece.org>$ 
    5:  * $copyright: Copyright (C) 1999 by Salvatore Sanfilippo$ 
    6:  * $license: This software is under GPL version 2 of license$ 
    7:  * $date: Fri Nov  5 11:55:49 MET 1999$ 
    8:  * $rev: 8$ 
    9:  */ 
   10: 
   11: #include <stdio.h>
   12: #include <string.h>
   13: #include <stdlib.h>
   14: #include <time.h>
   15: #include <sys/time.h>
   16: #include <unistd.h>
   17: #include <signal.h>
   18: 
   19: #include "hping2.h"
   20: #include "globals.h"
   21: 
   22: void send_tcp(void)
   23: {
   24: 	int			packet_size;
   25: 	int			tcp_opt_size = 0;
   26: 	char			*packet, *data;
   27: 	struct mytcphdr		*tcp;
   28: 	struct pseudohdr	*pseudoheader;
   29: 	unsigned char		*tstamp;
   30: 
   31: 	if (opt_tcp_timestamp)
   32: 		tcp_opt_size = 12;
   33: 
   34: 	packet_size = TCPHDR_SIZE + tcp_opt_size + data_size;
   35: 	packet = malloc(PSEUDOHDR_SIZE + packet_size);
   36: 	if (packet == NULL) {
   37: 		perror("[send_tcphdr] malloc()");
   38: 		return;
   39: 	}
   40: 	pseudoheader = (struct pseudohdr*) packet;
   41: 	tcp =  (struct mytcphdr*) (packet+PSEUDOHDR_SIZE);
   42: 	tstamp = (unsigned char*) (packet+PSEUDOHDR_SIZE+TCPHDR_SIZE);
   43: 	data = (char*) (packet+PSEUDOHDR_SIZE+TCPHDR_SIZE+tcp_opt_size);
   44: 	
   45: 	memset(packet, 0, PSEUDOHDR_SIZE+packet_size);
   46: 
   47: 	/* tcp pseudo header */
   48: 	memcpy(&pseudoheader->saddr, &local.sin_addr.s_addr, 4);
   49: 	memcpy(&pseudoheader->daddr, &remote.sin_addr.s_addr, 4);
   50: 	pseudoheader->protocol		= 6; /* tcp */
   51: 	pseudoheader->lenght		= htons(TCPHDR_SIZE+tcp_opt_size+data_size);
   52: 
   53: 	/* tcp header */
   54: 	tcp->th_dport	= htons(dst_port);
   55: 	tcp->th_sport	= htons(src_port);
   56: 
   57: 	/* sequence number and ack are random if not set */
   58: 	tcp->th_seq = (set_seqnum) ? htonl(tcp_seqnum) : htonl(rand());
   59: 	tcp->th_ack = (set_ack) ? htonl(tcp_ack) : htonl(rand());
   60: 
   61: 	tcp->th_off	= src_thoff + (tcp_opt_size >> 2);
   62: 	tcp->th_win	= htons(src_winsize);
   63: 	tcp->th_flags	= tcp_th_flags;
   64: 
   65: 	/* tcp timestamp option */
   66: 	if (opt_tcp_timestamp) {
   67: 		__u32 randts = rand() ^ (rand() << 16);
   68: 		tstamp[0] = tstamp[1] = 1; /* NOOP */
   69: 		tstamp[2] = 8;
   70: 		tstamp[3] = 10; /* 10 bytes, kind+len+T1+T2 */
   71: 		memcpy(tstamp+4, &randts, 4); /* random */
   72: 		memset(tstamp+8, 0, 4); /* zero */
   73: 	}
   74: 
   75: 	/* data */
   76: 	data_handler(data, data_size);
   77: 
   78: 	/* compute checksum */
   79: #ifdef STUPID_SOLARIS_CHECKSUM_BUG
   80: 	tcp->th_sum = packet_size;
   81: #else
   82: 	tcp->th_sum = cksum((u_short*) packet, PSEUDOHDR_SIZE +
   83: 		      packet_size);
   84: #endif
   85: 
   86: 	/* adds this pkt in delaytable */
   87: 	delaytable_add(sequence, src_port, time(NULL), get_usec(), S_SENT);
   88: 
   89: 	/* send packet */
   90: 	send_ip_handler(packet+PSEUDOHDR_SIZE, packet_size);
   91: 	free(packet);
   92: 
   93: 	sequence++;	/* next sequence number */
   94: 	if (!opt_keepstill)
   95: 		src_port = (sequence + initsport) % 65536;
   96: 
   97: 	if (opt_force_incdport)
   98: 		dst_port++;
   99: }