// Routine to respond to the arrival of block of
// packets over some particular link j.
// Assume concatenated headers aligned on 64KB.
// PL in each header is aligned on 2 bytes.
// This code is big-endian.
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
void ex(int e) {exit(printf("Local hardware fault %d\n", e));}
void sec(int e) {exit(printf("Bogus packet %d\n", e));}
void code(int e) {exit(printf("write more code %d\n", e));}
void lock(pthread_mutex_t * l) {
  if(pthread_mutex_lock(l)) exit(printf("Bad lockL\n"));}
void unlock(pthread_mutex_t * l) {
  if(pthread_mutex_unlock(l)) exit(printf("Bad lockU\n"));}
typedef unsigned long int li;
typedef unsigned short int si;
typedef unsigned int ui;
li const msk = (1L<<16)-1;
typedef struct {char type, oc, cur, pad; ui money; char turns[0];} ph;
extern pthread_mutex_t exc;
typedef struct {void *cur, *lim;} hb;
extern hb zh[16]; // under exc
extern short Open; // under exc
extern int booty; // under exc
void np(int j, ph * header, ui sz){
int hs = *(si *)((li)header-2);
ph * p = (ph*)((li)header-hs);
if((li)header&msk) {
// Do all the earlier packets in this block first.
  if (((li)p&msk) > ((li)header&msk)) ex(1);
  np(j, (void *)p, hs);}
  if(!p->type) { // A datagram
    int phl = 2*(4+((p->oc+1)>>1));
    if(10+phl >= sz) sec(1);
    int out = ({int c = p->cur; if(p->oc<c) sec(2);
      j^(15&p->turns[c>>1]>>((c&1)<<2));});
    ++p->cur;
    lock(&exc);
    if((Open>>out)&1) {
    {int y = p->money-3;
      if(y<0) code(3);
      p->money = y; booty+=3;}
    void * q = zh[out].cur+sz;
    if(q>zh[out].lim) code(4);
    zh[out].cur = (void *)p;
    unlock(&exc);
    memcpy(q, (void*)p+sizeof(ph), phl);
    memcpy(q+sizeof(ph), p, 10);}
    else code(1);}
  else if(p->type == 1) { // a packet for a circuit.
    code(2);}
}