This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

http://www.gnu.org/licenses/gpl.txt
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <ctype.h>
#include <sys/stat.h>

#ifdef WIN32
#include <winsock.h>
#include "winerr.h"

#define close closesocket
#define sleep Sleep
#else
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#endif

#define VER "0.1"

u_char *load_file(u_char *filename, int *size);
int create_socket(void);
u_char get_byte(u_char *data);
int get_num(u_char *data);
int create_rand_byte(u_char *data, int len, u_int *seed);
u_int resolv(char *host);
void std_err(void);

int main(int argc, char *argv[]) {
struct sockaddr_in peer,
peerl;
u_int seed;
int sd = 0,
i,
size,
randport = 0,
randbyte = 0,
loop = 0,
loopms = 0,
chr = 0;
u_short port,
sport = 0;
u_char *buff,
*filename = NULL;

#ifdef WIN32
WSADATA wsadata;
WSAStartup(MAKEWORD(1,0), &wsadata);
#endif

setbuf(stdout, NULL);

fputs("\n"
"UDPSZ "VER"\n"
"by Luigi Auriemma\n"
"e-mail: aluigi@autistici.org\n"
"web: aluigi.org\n"
"\n", stdout);

if(argc < 4) {
printf("\n"
"Usage: %s [options] <host> <port> <pck_size>\n"
"\n"
"Options:\n"
"-b BYTE fill the packet with byte BYTE, which can be a char or a hex\n"
" example: -b a or -b 0x61 or -b 61\n"
"-r random packet content\n"
"-s packet filled with incremental byte (use -b for the start byte)\n"
"-p PORT use source port PORT\n"
"-R random source port\n"
"-S sequential source port\n"
"-f FILE load the content of the packet from FILE, the size will be\n"
" truncated at pck_size, set it to -1 for using the file size\n"
"-l MS send infinite packets with a delay of MS milliseconds\n"
"\n", argv[0]);
exit(1);
}

argc -= 3;
for(i = 1; i < argc; i++) {
switch(argv[i][1]) {
case 'b': chr = get_byte(argv[++i]); break;
case 'r': randbyte = 1; break;
case 's': randbyte = 2; break;
case 'p': sport = get_num(argv[++i]); break;
case 'R': randport = 1; break;
case 'S': randport = 2; break;
case 'l': {
loop = 1;
loopms = get_num(argv[++i]);
} break;
case 'f': filename = argv[++i]; break;
default: {
printf("\nError: wrong command-line argument (%s)\n\n", argv[i]);
exit(1);
} break;
}
}

port = get_num(argv[argc + 1]);
size = get_num(argv[argc + 2]);

peer.sin_addr.s_addr = resolv(argv[argc]);
peer.sin_port = htons(port);
peer.sin_family = AF_INET;

printf("- target %s : %hu\n",
inet_ntoa(peer.sin_addr), port);

seed = time(NULL);

if(filename) {
buff = load_file(filename, &size);

} else {
buff = malloc(size);
if(!buff) std_err();

if(!randbyte) {
memset(buff, chr, size);
}
}
printf("- packet size: %d\n", size);

if(randport) {
peerl.sin_addr.s_addr = INADDR_ANY;
peerl.sin_port = htons(~seed);
peerl.sin_family = AF_INET;
} else {
sd = create_socket();
}

if(sport && !randport) {
peerl.sin_addr.s_addr = INADDR_ANY;
peerl.sin_port = htons(sport);
peerl.sin_family = AF_INET;
printf("- source port: %hu\n", sport);
if(bind(sd, (struct sockaddr *)&peerl, sizeof(peerl))
< 0) std_err();
}

#ifndef WIN32
loopms *= 1000;
#endif

printf("- send packets: ");
for(;;) {
if(randbyte == 2) {
memset(buff, chr++, size);
} else if(randbyte == 1) {
create_rand_byte(buff, size, &seed);
}
if(randport) {
sd = create_socket();
do {
if(randport == 2) { // sequential
peerl.sin_port = htons(sport++);
} else {
peerl.sin_port += seed; // not really random
}
} while(bind(sd, (struct sockaddr *)&peerl, sizeof(peerl)) < 0);
}

if(sendto(sd, buff, size, 0, (struct sockaddr *)&peer, sizeof(peer))
< 0) std_err();
fputc('.', stdout);

if(randport) {
close(sd);
}

if(!loop) break;
#ifdef WIN32
sleep(loopms);
#else
usleep(loopms);
#endif
}

if(!randport) {
close(sd);
}
free(buff);
printf("\n- finished\n");
return(0);
}

u_char *load_file(u_char *filename, int *size) {
struct stat xstat;
FILE *fd;
u_char *buff;

printf("- load file: %s\n", filename);
fd = fopen(filename, "rb");
if(!fd) std_err();

fstat(fileno(fd), &xstat);
if((*size < 0) || (*size > xstat.st_size)) {
*size = xstat.st_size;
}

buff = malloc(*size);
if(!buff) std_err();

fread(buff, *size, 1, fd);
fclose(fd);
return(buff);
}

int create_socket(void) {
int sd,
on = 1;

sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if(sd < 0) std_err();
setsockopt(sd, SOL_SOCKET, SO_BROADCAST, (char *)&on, sizeof(on)); // useful?
return(sd);
}

u_char get_byte(u_char *data) {
int chr;

if(strlen(data) == 1) {
return(data[0]);
}
if(tolower(data[1]) == 'x') {
data += 2;
} else if(tolower(data[0]) == 'x') {
data++;
}
sscanf(data, "%x", &chr);
return(chr);
}

int get_num(u_char *data) {
int num;

if(tolower(data[1]) == 'x') {
sscanf(data + 2, "%x", &num);

} else if(tolower(data[0]) == 'x') {
sscanf(data + 1, "%x", &num);

} else {
sscanf(data, "%d", &num);
}
return(num);
}

int create_rand_byte(u_char *data, int len, u_int *seed) {
u_int rnd;
u_char *p;

rnd = *seed;
p = data;

while(len--) {
rnd = (rnd * 0x343FD) + 0x269EC3;
rnd >>= 3; // useless???
*p++ = rnd & 0xff;
}

*seed = rnd;
return(p - data);
}

u_int resolv(char *host) {
struct hostent *hp;
u_int host_ip;

host_ip = inet_addr(host);
if(host_ip == INADDR_NONE) {
hp = gethostbyname(host);
if(!hp) {
printf("\nError: Unable to resolv hostname (%s)\n", host);
exit(1);
} else host_ip = *(u_int *)hp->h_addr;
}
return(host_ip);
}

#ifndef WIN32
void std_err(void) {
perror("\nError");
exit(1);
}
#endif