/*
 * reserved.c
 * 
 * Kevin P. Smith   7/3/89
 */
#include "copyright2.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include "netrek.h"

#ifdef GATEWAY
extern unsigned long netaddr;
#endif

void
makeReservedPacket(packet)
    struct reserved_spacket *packet;
{
   int             i;

   for (i = 0; i < 16; i++) {
      packet->data[i] = random() % 256;
   }
   packet->type = SP_RESERVED;
}

/* A "random" table we use to hose our data. */
static unsigned char swap[16][16] =
{
   {4, 13, 9, 7, 5, 8, 14, 2, 10, 11, 6, 3, 12, 15, 0, 1},
   {0, 4, 12, 5, 15, 2, 7, 3, 14, 6, 1, 10, 8, 13, 11, 9},
   {9, 5, 4, 2, 3, 6, 10, 12, 1, 7, 15, 14, 11, 0, 13, 8},
   {5, 8, 15, 4, 6, 9, 1, 12, 10, 3, 13, 11, 2, 7, 0, 14},
   {15, 13, 1, 14, 4, 0, 8, 12, 11, 9, 2, 10, 3, 6, 7, 5},
   {6, 7, 9, 11, 14, 1, 4, 13, 2, 12, 8, 15, 10, 0, 5, 3},
   {11, 0, 10, 14, 7, 12, 2, 4, 15, 13, 3, 9, 1, 5, 8, 6},
   {9, 8, 2, 10, 12, 14, 3, 7, 4, 0, 11, 1, 5, 15, 6, 13},
   {15, 12, 3, 0, 10, 8, 13, 9, 14, 2, 4, 5, 7, 6, 1, 11},
   {14, 3, 0, 11, 2, 10, 15, 12, 13, 1, 5, 4, 6, 8, 7, 9},
   {1, 2, 7, 3, 8, 0, 10, 14, 6, 5, 13, 12, 4, 9, 11, 15},
   {2, 1, 11, 9, 7, 3, 12, 6, 5, 8, 0, 10, 14, 4, 15, 13},
   {0, 12, 15, 1, 13, 7, 6, 5, 3, 14, 11, 8, 9, 10, 2, 4},
   {10, 9, 0, 6, 1, 14, 5, 12, 7, 4, 15, 13, 8, 2, 3, 11},
   {3, 11, 6, 12, 10, 5, 14, 1, 9, 15, 7, 2, 13, 8, 4, 0},
   {12, 6, 5, 8, 14, 4, 13, 15, 10, 0, 11, 9, 3, 1, 7, 2}
};

void
encryptReservedPacket(spacket, cpacket, server, pno)
    struct reserved_spacket *spacket;
    struct reserved_cpacket *cpacket;
    char           *server;
    int             pno;
{
   struct hostent *hp;
   struct in_addr  address;
   unsigned char   mixin1, mixin2, mixin3, mixin4, mixin5;
   int             i, j, k;
   char            buf[16];
   unsigned char  *s;
#ifndef GATEWAY
    unsigned long netaddr = 0;
#endif

   MCOPY(spacket->data, cpacket->data, 16);
   MCOPY(spacket->data, cpacket->resp, 16);
   cpacket->type = CP_RESERVED;

   if ((address.s_addr = inet_addr(server)) == -1) {
      if ((hp = gethostbyname(server)) == NULL) {
	 fprintf(stderr, "I don't know any %s!\n", server);
	 fflush(stderr);
	 exit(1);
      } else {
	 address.s_addr = *(long *) hp->h_addr;
      }
   }
   netaddr = htonl(address.s_addr);
   mixin1 = (netaddr >> 24) & 0xff;
   mixin2 = pno;
   mixin3 = (netaddr >> 16) & 0xff;
   mixin4 = (netaddr >> 8) & 0xff;
   mixin5 = netaddr & 0xff;

   j = 0;
   for (i = 0; i < 23; i++) {
      j = (j + cpacket->resp[j]) & 15;
      s = swap[j];
      cpacket->resp[s[i % 7]] ^= mixin1;
      cpacket->resp[s[i % 5]] ^= mixin2;
      cpacket->resp[s[i % 13]] ^= mixin3;
      cpacket->resp[s[i % 3]] ^= mixin4;
      cpacket->resp[s[i % 11]] ^= mixin5;
      for (k = 0; k < 16; k++) {
	 buf[k] = cpacket->resp[s[k]];
      }
      MCOPY(buf, cpacket->resp, 16);
   }
}