/*
    conf.c -- configuration code
    Copyright (C) 2003-2008 Marc Lehmann <gvpe@schmorp.de>
 
    This file is part of GVPE.

    GVPE 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 3 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, see <http://www.gnu.org/licenses/>.
   
    Additional permission under GNU GPL version 3 section 7
   
    If you modify this Program, or any covered work, by linking or
    combining it with the OpenSSL project's OpenSSL library (or a modified
    version of that library), containing parts covered by the terms of the
    OpenSSL or SSLeay licenses, the licensors of this Program grant you
    additional permission to convey the resulting work.  Corresponding
    Source for a non-source form of such a combination shall include the
    source code for the parts of OpenSSL used as well as that of the
    covered work.
*/

#include "config.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <errno.h>
#include <netdb.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "netcompat.h"

#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>
#include <openssl/bn.h>

#include "conf.h"
#include "slog.h"
#include "util.h"

char *confbase;
char *thisnode;
char *identname;

struct configuration conf;

u8
best_protocol (u8 protset)
{
  if (protset & PROT_IPv4  ) return PROT_IPv4;
  if (protset & PROT_ICMPv4) return PROT_ICMPv4;
  if (protset & PROT_UDPv4 ) return PROT_UDPv4;
  if (protset & PROT_TCPv4 ) return PROT_TCPv4;
  if (protset & PROT_DNSv4 ) return PROT_DNSv4;

  return 0;
}

const char *
strprotocol (u8 protocol)
{
  if (protocol & PROT_IPv4  ) return "rawip";
  if (protocol & PROT_ICMPv4) return "icmp";
  if (protocol & PROT_UDPv4 ) return "udp";
  if (protocol & PROT_TCPv4 ) return "tcp";
  if (protocol & PROT_DNSv4 ) return "dns";

  return "<unknown>";
}

static bool
match_list (const vector<const char *> &list, const char *str)
{
   for (vector<const char *>::const_iterator i = list.end (); i-- > list.begin (); )
     if ((*i)[0] == '*' && !(*i)[1])
       return true;
     else if (!strcmp (*i, str))
       return true;

   return false;
}

bool
conf_node::may_direct (struct conf_node *other)
{
  if (match_list (allow_direct, other->nodename))
    return true;

  if (match_list (deny_direct, other->nodename))
    return false;

  return true;
}

conf_node::~conf_node ()
{
#if 0
  // does not work, because string pointers etc. are shared
  // is not called, however
  if (rsa_key)
    RSA_free (rsa_key);

  free (nodename);
  free (hostname);
  free (if_up_data);
#if ENABLE_DNS
  free (domain);
  free (dns_hostname);
#endif
#endif
}

void
configuration::init ()
{
  memset (this, 0, sizeof (*this));

  mtu       = DEFAULT_MTU;
  nfmark    = 0;
  rekey     = DEFAULT_REKEY;
  keepalive = DEFAULT_KEEPALIVE;
  llevel    = L_INFO;
  ip_proto  = IPPROTO_GRE;
#if ENABLE_ICMP
  icmp_type = ICMP_ECHOREPLY;
#endif

  default_node.udp_port    = DEFAULT_UDPPORT;
  default_node.tcp_port    = DEFAULT_UDPPORT; // ehrm
  default_node.connectmode = conf_node::C_ALWAYS;
  default_node.compress    = true;
  default_node.protocols   = 0;
  default_node.max_retry   = DEFAULT_MAX_RETRY;
  default_node.max_ttl     = DEFAULT_MAX_TTL;
  default_node.max_queue   = DEFAULT_MAX_QUEUE;
  default_node.if_up_data  = strdup ("");

#if ENABLE_DNS
  default_node.dns_port    = 0; // default is 0 == client

  dns_forw_host       = strdup ("127.0.0.1");
  dns_forw_port       = 53;
  dns_timeout_factor  = DEFAULT_DNS_TIMEOUT_FACTOR;
  dns_send_interval   = DEFAULT_DNS_SEND_INTERVAL;
  dns_overlap_factor  = DEFAULT_DNS_OVERLAP_FACTOR;
  dns_max_outstanding = DEFAULT_DNS_MAX_OUTSTANDING;
#endif

  conf.pidfilename = strdup (LOCALSTATEDIR "/run/gvpe.pid");
}

void
configuration::cleanup ()
{
  if (rsa_key)
    RSA_free (rsa_key);

  rsa_key = 0;

  free (pidfilename);        pidfilename        = 0;
  free (ifname);             ifname             = 0;
#if ENABLE_HTTP_PROXY
  free (proxy_host);         proxy_host         = 0;
  free (proxy_auth);         proxy_auth         = 0;
#endif
#if ENABLE_DNS
  free (dns_forw_host);      dns_forw_host      = 0;
#endif
  free (script_if_up);       script_if_up       = 0;
  free (script_node_up);     script_node_up     = 0;
  free (script_node_change); script_node_change = 0;
  free (script_node_down);   script_node_down   = 0;
}

void
configuration::clear ()
{
  for (configuration::node_vector::iterator i = nodes.begin(); i != nodes.end(); ++i)
    delete *i;

  nodes.clear ();

  cleanup ();
  init ();
}

#define parse_bool(target,name,trueval,falseval) do {		\
  if      (!strcmp (val, "yes"))	target = trueval;	\
  else if (!strcmp (val, "no"))		target = falseval;	\
  else if (!strcmp (val, "true"))	target = trueval;	\
  else if (!strcmp (val, "false"))	target = falseval;	\
  else if (!strcmp (val, "on"))		target = trueval;	\
  else if (!strcmp (val, "off"))	target = falseval;	\
  else								\
    return _("illegal boolean value, only 'yes|true|on' or 'no|false|off' allowed. (ignored)"); \
} while (0)

const char *
configuration_parser::parse_line (char *line)
{
  {
    char *end = line + strlen (line);

    while (*end < ' ' && end >= line)
      end--;

    *++end = 0;
  }

  char *tok = line;
  const char *var = strtok (tok, "\t =");
  tok = 0;

  if (!var || !var[0])
    return 0;		/* no tokens on this line */

  if (var[0] == '#')
    return 0;		/* comment: ignore */

  char *val = strtok (NULL, "\t\n\r =");

  if (!val || val[0] == '#')
    return _("no value given for variable. (ignored)");

  if (!strcmp (var, "on"))
    {
      if (!::thisnode
          || (val[0] == '!' && strcmp (val + 1, ::thisnode))
          || !strcmp (val, ::thisnode))
        return parse_line (strtok (NULL, "\n\r"));
      else
        return 0;
    }

  // truly global
  if (!strcmp (var, "loglevel"))
    {
      loglevel l = string_to_loglevel (val);

      if (l == L_NONE)
        return _("unknown loglevel. (skipping)");
    }
  else if (!strcmp (var, "ip-proto"))
    conf.ip_proto = atoi (val);
  else if (!strcmp (var, "icmp-type"))
    {
#if ENABLE_ICMP
      conf.icmp_type = atoi (val);
#endif
    }

  // per config
  else if (!strcmp (var, "node"))
    {
      parse_argv ();

      conf.default_node.id++;
      node = new conf_node (conf.default_node);
      conf.nodes.push_back (node);
      node->nodename = strdup (val);

      {
        char *fname;
        FILE *f;

        asprintf (&fname, "%s/pubkey/%s", confbase, node->nodename);

        f = fopen (fname, "r");
        if (f)
          {
            node->rsa_key = RSA_new ();

            if (!PEM_read_RSAPublicKey(f, &node->rsa_key, NULL, NULL))
              {
                ERR_load_RSA_strings (); ERR_load_PEM_strings ();
                slog (L_ERR, _("unable to open public rsa key file '%s': %s"), fname, ERR_error_string (ERR_get_error (), 0));
                exit (EXIT_FAILURE);
              }

            require (RSA_blinding_on (node->rsa_key, 0));

            fclose (f);
          }
        else
          {
            slog (need_keys ? L_ERR : L_NOTICE, _("unable to read public rsa key file '%s': %s"), fname, strerror (errno));

            if (need_keys)
              exit (EXIT_FAILURE);
          }

        free (fname);
      }

      if (::thisnode && !strcmp (node->nodename, ::thisnode))
        conf.thisnode = node;
    }
  else if (!strcmp (var, "private-key"))
    free (conf.prikeyfile), conf.prikeyfile = strdup (val);
  else if (!strcmp (var, "ifpersist"))
    parse_bool (conf.ifpersist, "ifpersist", true, false);
  else if (!strcmp (var, "ifname"))
    free (conf.ifname), conf.ifname = strdup (val);
  else if (!strcmp (var, "rekey"))
    conf.rekey = atoi (val);
  else if (!strcmp (var, "keepalive"))
    conf.keepalive = atoi (val);
  else if (!strcmp (var, "mtu"))
    conf.mtu = atoi (val);
  else if (!strcmp (var, "nfmark"))
    conf.nfmark = atoi (val);
  else if (!strcmp (var, "if-up"))
    free (conf.script_if_up), conf.script_if_up = strdup (val);
  else if (!strcmp (var, "node-up"))
    free (conf.script_node_up), conf.script_node_up = strdup (val);
  else if (!strcmp (var, "node-change"))
    free (conf.script_node_change), conf.script_node_change = strdup (val);
  else if (!strcmp (var, "node-down"))
    free (conf.script_node_down), conf.script_node_down = strdup (val);
  else if (!strcmp (var, "pid-file"))
    free (conf.pidfilename), conf.pidfilename = strdup (val);
  else if (!strcmp (var, "dns-forw-host"))
    {
#if ENABLE_DNS
      free (conf.dns_forw_host), conf.dns_forw_host = strdup (val);
#endif
    }
  else if (!strcmp (var, "dns-forw-port"))
    {
#if ENABLE_DNS
      conf.dns_forw_port = atoi (val);
#endif
    }
  else if (!strcmp (var, "dns-timeout-factor"))
    {
#if ENABLE_DNS
      conf.dns_timeout_factor = atof (val);
#endif
    }
  else if (!strcmp (var, "dns-send-interval"))
    {
#if ENABLE_DNS
      conf.dns_send_interval = atoi (val);
#endif
    }
  else if (!strcmp (var, "dns-overlap-factor"))
    {
#if ENABLE_DNS
      conf.dns_overlap_factor = atof (val);
#endif
    }
  else if (!strcmp (var, "dns-max-outstanding"))
    {
#if ENABLE_DNS
      conf.dns_max_outstanding = atoi (val);
#endif
    }
  else if (!strcmp (var, "http-proxy-host"))
    {
#if ENABLE_HTTP_PROXY
      free (conf.proxy_host), conf.proxy_host = strdup (val);
#endif
    }
  else if (!strcmp (var, "http-proxy-port"))
    {
#if ENABLE_HTTP_PROXY
      conf.proxy_port = atoi (val);
#endif
    }
  else if (!strcmp (var, "http-proxy-auth"))
    {
#if ENABLE_HTTP_PROXY
      conf.proxy_auth = (char *)base64_encode ((const u8 *)val, strlen (val));
#endif
    }

  /* node-specific, non-defaultable */
  else if (node != &conf.default_node && !strcmp (var, "hostname"))
    free (node->hostname), node->hostname = strdup (val);

  /* node-specific, defaultable */
  else if (!strcmp (var, "udp-port"))
    node->udp_port = atoi (val);
  else if (!strcmp (var, "tcp-port"))
    node->tcp_port = atoi (val);
  else if (!strcmp (var, "dns-hostname"))
    {
#if ENABLE_DNS
      free (node->dns_hostname), node->dns_hostname = strdup (val);
#endif
    }
  else if (!strcmp (var, "dns-port"))
    {
#if ENABLE_DNS
      node->dns_port = atoi (val);
#endif
    }
  else if (!strcmp (var, "dns-domain"))
    {
#if ENABLE_DNS
      free (node->domain), node->domain = strdup (val);
#endif
    }
  else if (!strcmp (var, "if-up-data"))
    free (node->if_up_data), node->if_up_data = strdup (val);
  else if (!strcmp (var, "router-priority"))
    node->routerprio = atoi (val);
  else if (!strcmp (var, "max-retry"))
    node->max_retry = atoi (val);
  else if (!strcmp (var, "connect"))
    {
      if (!strcmp (val, "ondemand"))
        node->connectmode = conf_node::C_ONDEMAND;
      else if (!strcmp (val, "never"))
        node->connectmode = conf_node::C_NEVER;
      else if (!strcmp (val, "always"))
        node->connectmode = conf_node::C_ALWAYS;
      else if (!strcmp (val, "disabled"))
        node->connectmode = conf_node::C_DISABLED;
      else
        return _("illegal value for 'connectmode', use one of 'ondemand', 'never', 'always' or 'disabled'. (ignored)");
    }
  else if (!strcmp (var, "inherit-tos"))
    parse_bool (node->inherit_tos, "inherit-tos", true, false);
  else if (!strcmp (var, "compress"))
    parse_bool (node->compress, "compress", true, false);
  // all these bool options really really cost a lot of executable size!
  else if (!strcmp (var, "enable-tcp"))
    {
#if ENABLE_TCP
      u8 v; parse_bool (v, "enable-tcp" , PROT_TCPv4, 0); node->protocols = (node->protocols & ~PROT_TCPv4) | v;
#endif
    }
  else if (!strcmp (var, "enable-icmp"))
    {
#if ENABLE_ICMP
      u8 v; parse_bool (v, "enable-icmp" , PROT_ICMPv4, 0); node->protocols = (node->protocols & ~PROT_ICMPv4) | v;
#endif
    }
  else if (!strcmp (var, "enable-dns"))
    {
#if ENABLE_DNS
      u8 v; parse_bool (v, "enable-dns" , PROT_DNSv4, 0); node->protocols = (node->protocols & ~PROT_DNSv4) | v;
#endif
    }
  else if (!strcmp (var, "enable-udp"))
    {
      u8 v; parse_bool (v, "enable-udp" , PROT_UDPv4, 0); node->protocols = (node->protocols & ~PROT_UDPv4) | v;
    }
  else if (!strcmp (var, "enable-rawip"))
    {
      u8 v; parse_bool (v, "enable-rawip", PROT_IPv4, 0); node->protocols = (node->protocols & ~PROT_IPv4 ) | v;
    }
  else if (!strcmp (var, "allow-direct"))
    node->allow_direct.push_back (strdup (val));
  else if (!strcmp (var, "deny-direct"))
    node->deny_direct.push_back (strdup (val));
  else if (!strcmp (var, "max-ttl"))
    node->max_ttl = atof (val);
  else if (!strcmp (var, "max-queue"))
    node->max_queue = atoi (val);

  // unknown or misplaced
  else
    return _("unknown configuration directive. (ignored)");

  return 0;
}

void
conf_node::finalise ()
{
  if (max_queue < 1)
    {
      slog (L_WARN, _("%s: max-queue value invalid, setting it to 1."), nodename);
      max_queue = 1;
    }

  if (routerprio > 1 && (connectmode != C_ALWAYS && connectmode != C_DISABLED))
    {
      //slog (L_WARN, _("%s: has non-zero router-priority but either 'never' or 'ondemand' as connectmode, setting it to 'always'."), nodename);
      connectmode = C_ALWAYS;
    }
}

void
configuration_parser::parse_argv ()
{
  for (int i = 0; i < argc; ++i)
    {
      char *v = argv [i];

      if (!*v)
        continue;

      char *enode = v;

      while (*enode != '.' && *enode > ' ' && *enode != '=' && *enode)
        enode++;

      if (*enode != '.')
        enode = 0;

      char *wnode = node == &conf.default_node
                    ? 0
                    : node->nodename;

      if ((!wnode && !enode)
          || (wnode && enode && !strncmp (wnode, v, enode - v)))
        {
          const char *warn = parse_line (enode ? enode + 1 : v);

          if (warn)
            slog (L_WARN, _("%s, while parsing command line option '%s'."), warn, v);

          *v = 0;
        }
    }
}

configuration_parser::configuration_parser (configuration &conf,
                                            bool need_keys,
                                            int argc,
                                            char **argv)
: conf (conf),need_keys (need_keys), argc (argc), argv (argv)
{
  char *fname;
  FILE *f;

  conf.clear ();

  asprintf (&fname, "%s/gvpe.conf", confbase);
  f = fopen (fname, "r");

  if (f)
    {
      char line[16384];
      int lineno = 0;
      node = &conf.default_node;

      while (fgets (line, sizeof (line), f))
        {
          lineno++;

          const char *warn = parse_line (line);

          if (warn)
            slog (L_WARN, _("%s, at '%s', line %d."), warn, fname, lineno);
        }

      fclose (f);

      parse_argv ();
    }
  else
    {
      slog (L_ERR, _("unable to read config file '%s': %s"), fname, strerror (errno));
      exit (EXIT_FAILURE);
    }

  free (fname);

  fname = conf.config_filename (conf.prikeyfile, "hostkey");

  f = fopen (fname, "r");
  if (f)
    {
      conf.rsa_key = RSA_new ();

      if (!PEM_read_RSAPrivateKey (f, &conf.rsa_key, NULL, NULL))
        {
          ERR_load_RSA_strings (); ERR_load_PEM_strings ();
          slog (L_ERR, _("unable to read private rsa key file '%s': %s"), fname, ERR_error_string (ERR_get_error (), 0));
          exit (EXIT_FAILURE);
        }

      require (RSA_blinding_on (conf.rsa_key, 0));

      fclose (f);
    }
  else
    {
      slog (need_keys ? L_ERR : L_NOTICE, _("unable to open private rsa key file '%s': %s"), fname, strerror (errno));

      if (need_keys)
        exit (EXIT_FAILURE);
    }

  if (need_keys && ::thisnode
      && conf.rsa_key && conf.thisnode && conf.thisnode->rsa_key)
    if (BN_cmp (conf.rsa_key->n, conf.thisnode->rsa_key->n) != 0
        || BN_cmp (conf.rsa_key->e, conf.thisnode->rsa_key->e) != 0)
      {
        slog (L_NOTICE, _("private hostkey and public node key mismatch: is '%s' the correct node?"), ::thisnode);
        exit (EXIT_FAILURE);
      }

  free (fname);

  for (configuration::node_vector::iterator i = conf.nodes.begin(); i != conf.nodes.end(); ++i)
    (*i)->finalise ();
}

char *
configuration::config_filename (const char *name, const char *dflt)
{
  char *fname;

  asprintf (&fname, name ? name : dflt, ::thisnode);

  if (!ABSOLUTE_PATH (fname))
    {
      char *rname = fname;
      asprintf (&fname, "%s/%s", confbase, rname);
      free (rname);
    }

  return fname;
}

void
conf_node::print ()
{
  printf ("%4d  fe:fd:80:00:0%1x:%02x  %c  %-8.8s  %-10.10s   %02x  %s%s%d\n",
          id,
          id >> 8, id & 0xff,
          compress ? 'Y' : 'N',
          connectmode   == C_ONDEMAND ? "ondemand"
          : connectmode == C_NEVER    ? "never"
          : connectmode == C_ALWAYS   ? "always"
          : connectmode == C_DISABLED ? "disabled"
          :                             "",
          nodename,
          protocols,
          hostname ? hostname : "",
          hostname ? ":" : "",
          hostname ? udp_port : 0
          );
}

void
configuration::print ()
{
  printf (_("\nConfiguration\n\n"));
  printf (_("# of nodes:         %d\n"), nodes.size ());
  printf (_("this node:          %s\n"), thisnode ? thisnode->nodename : "<unset>");
  printf (_("MTU:                %d\n"), mtu);
  printf (_("rekeying interval:  %d\n"), rekey);
  printf (_("keepalive interval: %d\n"), keepalive);
  printf (_("interface:          %s\n"), ifname);
  printf (_("primary rsa key:    %s\n"), prikeyfile ? prikeyfile : "<default>");
  printf (_("rsa key size:       %d\n"), rsa_key ? RSA_size (rsa_key) * 8 : -1);
  printf ("\n");

  printf ("%4s  %-17s %s %-8.8s  %-10.10s  %04s %s\n",
          _("ID#"), _("MAC"), _("Com"), _("Conmode"), _("Node"), _("Prot"), _("Host:Port"));

  for (node_vector::iterator i = nodes.begin (); i != nodes.end (); ++i)
    (*i)->print ();

  printf ("\n");
}

configuration::configuration ()
{
  asprintf (&confbase, "%s/gvpe", CONFDIR);

  init ();
}

configuration::~configuration ()
{
  cleanup ();
}