/*  * $smu-mark$  * $name: sendtcp.c$  * $author: Salvatore Sanfilippo <antirez@invece.org>$  * $copyright: Copyright (C) 1999 by Salvatore Sanfilippo$  * $license: This software is under GPL version 2 of license$  * $date: Fri Nov  5 11:55:49 MET 1999$  * $rev: 8$  */ #include <stdio.h>#include <string.h>#include <stdlib.h>#include <sys/time.h>#include <unistd.h>#include <signal.h>#include <errno.h>#include "hping2.h"#include "globals.h"void send_tcphdr (int signal_id){	int			packet_size;	int			tcp_opt_size = 0;	int			errno_save = errno;	char			*packet, *data;	struct mytcphdr		*tcp;	struct pseudohdr	*pseudoheader;	unsigned char		*tstamp;	if (opt_tcp_timestamp)		tcp_opt_size = 12;	packet_size = TCPHDR_SIZE + tcp_opt_size + data_size;	packet = malloc(PSEUDOHDR_SIZE + packet_size);	if (packet == NULL) {		perror("[send_tcphdr] malloc()");		errno = errno_save;		return;	}	pseudoheader = (struct pseudohdr*) packet;	tcp =  (struct mytcphdr*) (packet+PSEUDOHDR_SIZE);	tstamp = (unsigned char*) (packet+PSEUDOHDR_SIZE+TCPHDR_SIZE);	data = (char*) (packet+PSEUDOHDR_SIZE+TCPHDR_SIZE+tcp_opt_size);		memset(packet, 0, PSEUDOHDR_SIZE+packet_size);	/* tcp pseudo header */	memcpy(&pseudoheader->saddr, &local.sin_addr.s_addr, 4);	memcpy(&pseudoheader->daddr, &remote.sin_addr.s_addr, 4);	pseudoheader->protocol		= 6; /* tcp */	pseudoheader->lenght		= htons(TCPHDR_SIZE+tcp_opt_size+data_size);	/* tcp header */	tcp->th_dport	= htons(dst_port);	tcp->th_sport	= htons(src_port);	/* sequence number and ack are random if not set */	tcp->th_seq = (set_seqnum) ? htonl(tcp_seqnum) : htonl(rand());	tcp->th_ack = (set_ack) ? htonl(tcp_ack) : htonl(rand());	tcp->th_off	= src_thoff + (tcp_opt_size >> 2);	tcp->th_win	= htons(src_winsize);	tcp->th_flags	= tcp_th_flags;	/* tcp timestamp option */	if (opt_tcp_timestamp) {		__u32 randts = rand() ^ (rand() << 16);		tstamp[0] = tstamp[1] = 1; /* NOOP */		tstamp[2] = 8;		tstamp[3] = 10; /* 10 bytes, kind+len+T1+T2 */		memcpy(tstamp+4, &randts, 4); /* random */		memset(tstamp+8, 0, 4); /* zero */	}	/* data */	data_handler(data, data_size);	/* compute checksum */#ifdef STUPID_SOLARIS_CHECKSUM_BUG	tcp->th_sum = packet_size;#else	tcp->th_sum = cksum((u_short*) packet, PSEUDOHDR_SIZE +		      packet_size);#endif	/* adds this pkt in delaytable */	delaytable[delaytable_index % TABLESIZE].seq = sequence;	delaytable[delaytable_index % TABLESIZE].src = src_port;	delaytable[delaytable_index % TABLESIZE].sec = time(NULL);	delaytable[delaytable_index % TABLESIZE].usec = get_usec();	delaytable[delaytable_index % TABLESIZE].status = S_SENT;	/* send packet */	send_ip_handler(packet+PSEUDOHDR_SIZE, packet_size);	free(packet);	delaytable_index++;	sent_pkt++;	Signal(SIGALRM, send_tcphdr);		if (count != -1 && count == sent_pkt)	/* count reached */	{		Signal(SIGALRM, print_statistics);		alarm(COUNTREACHED_TIMEOUT);	}	else if (!opt_listenmode)	{		if (opt_waitinusec == FALSE)			alarm(sending_wait);		else			setitimer(ITIMER_REAL, &usec_delay, NULL);	}	sequence++;	/* next sequence number */	if (!opt_keepstill)		src_port = (sequence + initsport) % 65536;	if (opt_force_incdport)		dst_port++;	errno = errno_save;}