#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include <crypt.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

char *hash = "hqDTK7b8K2rvw";
#define GCHQ 0x71686367

static int contact(const char *host, const uint32_t *u)
{
  int sk;
  struct hostent *h;
  ssize_t n;
  struct sockaddr_in sin;
  char buf[256];

  if (!(h = gethostbyname(host))) {
    printf("error: gethostbyname() failed\n");
    return (-1);
  }
  sin.sin_family = h->h_addrtype;
  memcpy(&sin.sin_addr, h->h_addr, h->h_length);
  sin.sin_port = htons(80);

  sk = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (connect(sk, (struct sockaddr *)&sin, sizeof(sin))) {
    printf("error: connect(\"%s\") failed\n", host);
    return (-1);
  }

  sprintf(buf, "GET /%s/%x/%x/%x/key.txt HTTP/1.0\r\n\r\n",
	  hash, u[0], u[1], u[2]);
  printf("request:\n\n%s", buf);
  if (send(sk, buf, strlen(buf), 0) <= 0) {
    printf("error: send() failed\n");
    return (-1);
  }

  printf("response\n\n");
  for (;;) {
    memset(buf, 0, sizeof(buf));
    if ((n = recv(sk, buf, sizeof(buf) - 1, 0)) <= 0)
      break;
    printf("%s", buf);
  }
  printf("\n");
  return (n);
}

int main(int argc, char *argv[])
{
  FILE *fp;
  uint32_t u[3];
  union { char c[44]; uint32_t u[6]; } buf;
  int validp = 0;

  printf("\nkeygen.exe\n\n");

  if (argc != 2) {
    printf("usage: keygen.exe hostname\n");
    return (-1);
  }

  if (!(fp = fopen("license.txt", "r"))) {
    printf("error: license.txt not found\n");
    return (-1);
  }
  memset(buf.u, 0, sizeof(buf.u));
  fscanf(fp, "%s", buf.c);
  fclose(fp);

  if (buf.u[0] == GCHQ) {
    if (strcmp(crypt(buf.c + 4, hash), hash) == 0)
      validp = 1;
    printf("loading stage1 license key(s)\n");
    u[0] = buf.u[3];
    printf("loading stage2 license key(s)\n");
    u[1] = buf.u[4];
    u[2] = buf.u[5];
  }
  if (!validp) {
    printf("error: license.txt invalid\n");
    return (-1);
  }

  return (contact(argv[1], u));
}