gvpe/src/vpn.C

/*
    vpn.C -- handle the protocol, encryption, handshaking etc.
 
    This program 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 2 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, write to the Free Software
    Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "config.h"

#include <list>

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

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <sys/wait.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip_icmp.h>

#include "pidfile.h"

#include "connection.h"
#include "util.h"
#include "vpn.h"

/////////////////////////////////////////////////////////////////////////////

const char *vpn::script_if_up ()
{
  // the tunnel device mtu should be the physical mtu - overhead
  // the tricky part is rounding to the cipher key blocksize
  int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
  mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
  mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
  mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again

  char *env;
  asprintf (&env, "CONFBASE=%s", confbase);
  putenv (env);
  asprintf (&env, "NODENAME=%s", THISNODE->nodename);
  putenv (env);
  asprintf (&env, "NODEID=%d", THISNODE->id);
  putenv (env);
  asprintf (&env, "IFNAME=%s", tap->interface ());
  putenv (env);
  asprintf (&env, "MTU=%d", mtu);
  putenv (env);
  asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
            0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
            THISNODE->id & 0xff);
  putenv (env);

  return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
}

int
vpn::setup ()
{
  ipv4_fd = -1;

  if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
    {
      ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);

      if (ipv4_fd < 0)
        return -1;

      fcntl (ipv4_fd, F_SETFL, O_NONBLOCK);

#ifdef IP_MTU_DISCOVER
      // this I really consider a linux bug. I am neither connected
      // nor do I fragment myself. Linux still sets DF and doesn't
      // fragment for me sometimes.
      {
        int oval = IP_PMTUDISC_DONT;
        setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
      }
#endif

      sockinfo si (THISNODE, PROT_IPv4);

      if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
        {
          slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
          exit (1);
        }

      ipv4_ev_watcher.start (ipv4_fd, POLLIN);
    }

  udpv4_fd = -1;

  if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
    {
      udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);

      if (udpv4_fd < 0)
        return -1;

      fcntl (udpv4_fd, F_SETFL, O_NONBLOCK);

      // standard daemon practise...
      {
        int oval = 1;
        setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
      }

#ifdef IP_MTU_DISCOVER
      // this I really consider a linux bug. I am neither connected
      // nor do I fragment myself. Linux still sets DF and doesn't
      // fragment for me sometimes.
      {
        int oval = IP_PMTUDISC_DONT;
        setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
      }
#endif

      sockinfo si (THISNODE, PROT_UDPv4);

      if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
        {
          slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
          exit (1);
        }

      udpv4_ev_watcher.start (udpv4_fd, POLLIN);
    }

  icmpv4_fd = -1;

#if ENABLE_ICMP
  if (THISNODE->protocols & PROT_ICMPv4)
    {
      icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);

      if (icmpv4_fd < 0)
        return -1;

      fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK);

#ifdef ICMP_FILTER
      {
        icmp_filter oval;
        oval.data = 0xffffffff;
        if (::conf.icmp_type < 32)
          oval.data &= ~(1 << ::conf.icmp_type);

        setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
      }
#endif

#ifdef IP_MTU_DISCOVER
      // this I really consider a linux bug. I am neither connected
      // nor do I fragment myself. Linux still sets DF and doesn't
      // fragment for me sometimes.
      {
        int oval = IP_PMTUDISC_DONT;
        setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
      }
#endif

      sockinfo si (THISNODE, PROT_ICMPv4);

      if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
        {
          slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
          exit (1);
        }

      icmpv4_ev_watcher.start (icmpv4_fd, POLLIN);
    }
#endif

  tcpv4_fd = -1;

#if ENABLE_TCP
  if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
    {
      tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);

      if (tcpv4_fd < 0)
        return -1;

      fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK);

      // standard daemon practise...
      {
        int oval = 1;
        setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
      }

      sockinfo si (THISNODE, PROT_TCPv4);

      if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
        {
          slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
          exit (1);
        }

      if (listen (tcpv4_fd, 5))
        {
          slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
          exit (1);
        }

      tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
    }
#endif

  tap = new tap_device ();
  if (!tap) //D this, of course, never catches
    {
      slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
      exit (1);
    }
  
  run_script (run_script_cb (this, &vpn::script_if_up), true);

  tap_ev_watcher.start (tap->fd, POLLIN);

  reconnect_all ();

  return 0;
}

// send a vpn packet out to other hosts
bool
vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
{
  switch (si.prot)
    {
      case PROT_IPv4:
        return send_ipv4_packet (pkt, si, tos);

      case PROT_UDPv4:
        return send_udpv4_packet (pkt, si, tos);

#if ENABLE_TCP
      case PROT_TCPv4:
        return send_tcpv4_packet (pkt, si, tos);
#endif

#if ENABLE_ICMP
      case PROT_ICMPv4:
        return send_icmpv4_packet (pkt, si, tos);
#endif

      default:
        slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
        return false;
    }
}

bool
vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
{
  setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
  sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());

  return true;
}

static u16
ipv4_checksum (u16 *data, unsigned int len)
{
  // use 32 bit accumulator and fold back carry bits at the end
  u32 sum = 0;

  while (len > 1)
    {
      sum += *data++;
      len -= 2;
    }

  // odd byte left?
  if (len)
    sum += *(u8 *)data;

  // add back carry bits
  sum = (sum >> 16) + (sum & 0xffff);   // lo += hi
  sum += (sum >> 16);                   // carry

  return ~sum;
}

bool
vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
{
  setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);

  pkt->unshift_hdr (4);

  icmphdr *hdr = (icmphdr *)&((*pkt)[0]);
  hdr->type = ::conf.icmp_type;
  hdr->code = 255;
  hdr->checksum = 0;
  hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);

  sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());

  return true;
}

bool
vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
{
  setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
  sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());

  return true;
}

void
vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
{
  unsigned int src = pkt->src ();
  unsigned int dst = pkt->dst ();

  slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
        (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);

  if (src == 0 || src > conns.size ()
      || dst > conns.size ()
      || pkt->typ () >= vpn_packet::PT_MAX)
    slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
          (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
  else if (dst > conns.size ())
    slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
          (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
  else
    {
      connection *c = conns[src - 1];

      if (dst == 0 && !THISNODE->routerprio)
        slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
              c->conf->nodename, (const char *)rsi);
      else if (dst != 0 && dst != THISNODE->id)
        {
          if (THISNODE->routerprio)
            // the tos setting gets lost here. who cares.
            conns[dst - 1]->inject_vpn_packet (pkt);
          else
            slog (L_WARN,
                  _("%s(%s): forwarding request (=> %s), but we are no router"),
                  c->conf->nodename, (const char *)rsi,
                  conns[dst - 1]->conf->nodename);
        }
      else
        c->recv_vpn_packet (pkt, rsi);
    }
}

void
vpn::ipv4_ev (io_watcher &w, short revents)
{
  if (revents & (POLLIN | POLLERR))
    {
      vpn_packet *pkt = new vpn_packet;
      struct sockaddr_in sa;
      socklen_t sa_len = sizeof (sa);
      int len;

      len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);

      sockinfo si(sa, PROT_IPv4);

      if (len > 0)
        {
          pkt->len = len;

          // raw sockets deliver the ipv4, but don't expect it on sends
          // this is slow, but...
          pkt->skip_hdr (IP_OVERHEAD);

          recv_vpn_packet (pkt, si);
        }
      else
        {
          // probably ECONNRESET or somesuch
          slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
        }

      delete pkt;
    }
  else if (revents & POLLHUP)
    {
      // this cannot ;) happen on udp sockets
      slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
      exit (1);
    }
  else
    {
      slog (L_ERR,
              _("FATAL: unknown revents %08x in socket, terminating\n"),
              revents);
      exit (1);
    }
}

void
vpn::icmpv4_ev (io_watcher &w, short revents)
{
  if (revents & (POLLIN | POLLERR))
    {
      vpn_packet *pkt = new vpn_packet;
      struct sockaddr_in sa;
      socklen_t sa_len = sizeof (sa);
      int len;

      len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);

      sockinfo si(sa, PROT_ICMPv4);

      if (len > 0)
        {
          pkt->len = len;

          icmphdr *hdr = (icmphdr *)&((*pkt)[IP_OVERHEAD]);

          if (hdr->type == ::conf.icmp_type
              && hdr->code == 255)
            {
              // raw sockets deliver the ipv4, but don't expect it on sends
              // this is slow, but...
              pkt->skip_hdr (ICMP_OVERHEAD);

              recv_vpn_packet (pkt, si);
            }
        }
      else
        {
          // probably ECONNRESET or somesuch
          slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
        }

      delete pkt;
    }
  else if (revents & POLLHUP)
    {
      // this cannot ;) happen on udp sockets
      slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
      exit (1);
    }
  else
    {
      slog (L_ERR,
              _("FATAL: unknown revents %08x in socket, terminating\n"),
              revents);
      exit (1);
    }
}

void
vpn::udpv4_ev (io_watcher &w, short revents)
{
  if (revents & (POLLIN | POLLERR))
    {
      vpn_packet *pkt = new vpn_packet;
      struct sockaddr_in sa;
      socklen_t sa_len = sizeof (sa);
      int len;

      len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);

      sockinfo si(sa, PROT_UDPv4);

      if (len > 0)
        {
          pkt->len = len;

          recv_vpn_packet (pkt, si);
        }
      else
        {
          // probably ECONNRESET or somesuch
          slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
        }

      delete pkt;
    }
  else if (revents & POLLHUP)
    {
      // this cannot ;) happen on udp sockets
      slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
      exit (1);
    }
  else
    {
      slog (L_ERR,
              _("FATAL: unknown revents %08x in socket, terminating\n"),
              revents);
      exit (1);
    }
}

void
vpn::tap_ev (io_watcher &w, short revents)
{
  if (revents & POLLIN)
    {
      /* process data */
      tap_packet *pkt;

      pkt = tap->recv ();

      int dst = mac2id (pkt->dst);
      int src = mac2id (pkt->src);

      if (src != THISNODE->id)
        {
          slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
          exit (1);
        }

      if (dst == THISNODE->id)
        {
          slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
          exit (1);
        }

      if (dst > conns.size ())
        slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
      else
        {
          if (dst)
            {
              // unicast
              if (dst != THISNODE->id)
                conns[dst - 1]->inject_data_packet (pkt);
            }
          else
            {
              // broadcast, first check router, then self, then english
              connection *router = find_router ();

              if (router)
                router->inject_data_packet (pkt, true);
              else
                for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
                  if ((*c)->conf != THISNODE)
                    (*c)->inject_data_packet (pkt);
            }
        }

      delete pkt;
    }
  else if (revents & (POLLHUP | POLLERR))
    {
      slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
      exit (1);
    }
  else
    abort ();
}

void
vpn::event_cb (time_watcher &w)
{
  if (events)
    {
      if (events & EVENT_SHUTDOWN)
        {
          slog (L_INFO, _("preparing shutdown..."));

          shutdown_all ();

          remove_pid (pidfilename);

          slog (L_INFO, _("terminating"));

          exit (0);
        }

      if (events & EVENT_RECONNECT)
        {
          slog (L_INFO, _("forced reconnect"));

          reconnect_all ();
        }

      events = 0;
    }

  w.at = TSTAMP_CANCEL;
}

void
vpn::shutdown_all ()
{
  for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
    (*c)->shutdown ();
}

void
vpn::reconnect_all ()
{
  for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
    delete *c;

  conns.clear ();

  connection_init ();

  for (configuration::node_vector::iterator i = conf.nodes.begin ();
       i != conf.nodes.end (); ++i)
    {
      connection *conn = new connection (this);

      conn->conf = *i;
      conns.push_back (conn);

      conn->establish_connection ();
    }
}

connection *vpn::find_router ()
{
  u32 prio = 1;
  connection *router = 0;

  for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
    {
      connection *c = *i;

      if (c->conf->routerprio >= prio
          && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
          && c->ictx && c->octx
          && c->conf != THISNODE                   // redundant, since ictx==octx==0 always on thisnode
          && (!THISNODE->routerprio
              || c->conf->routerprio <= THISNODE->routerprio))
        {
          prio = c->conf->routerprio;
          router = c;
        }
    }

  return router;
}

void vpn::send_connect_request (int id)
{
  connection *c = find_router ();

  if (c)
    c->send_connect_request (id);
  else
    // no router found, aggressively connect to all routers
    for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
      if ((*i)->conf->routerprio)
        (*i)->establish_connection ();
}

void
connection::dump_status ()
{
  slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
  slog (L_NOTICE, _("  connectmode %d (%d) / sockaddr %s / minor %d"),
        connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
  slog (L_NOTICE, _("  ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
        (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
  slog (L_NOTICE, _("  establish_conn %ld / rekey %ld / keepalive %ld"),
        (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
}

void
vpn::dump_status ()
{
  slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);

  for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
    (*c)->dump_status ();

  slog (L_NOTICE, _("END status dump"));
}

vpn::vpn (void)
: event            (this, &vpn::event_cb)
, udpv4_ev_watcher (this, &vpn::udpv4_ev)
, ipv4_ev_watcher  (this, &vpn::ipv4_ev)
#if ENABLE_TCP
, tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
#endif
#if ENABLE_ICMP
, icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
#endif
, tap_ev_watcher   (this, &vpn::tap_ev)
{
}

vpn::~vpn ()
{
}

Revision:	1.12
Committed:	Sun Apr 13 00:42:04 2003 UTC (21 years, 1 month ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.11:	+2 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1	/*
2			vpn.C -- handle the protocol, encryption, handshaking etc.
3
4			This program is free software; you can redistribute it and/or modify
5			it under the terms of the GNU General Public License as published by
6			the Free Software Foundation; either version 2 of the License, or
7			(at your option) any later version.
8
9			This program is distributed in the hope that it will be useful,
10			but WITHOUT ANY WARRANTY; without even the implied warranty of
11			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12			GNU General Public License for more details.
13
14			You should have received a copy of the GNU General Public License
15			along with this program; if not, write to the Free Software
16			Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17			*/
18
19			#include "config.h"
20
21			#include <list>
22
23			#include <cstdlib>
24			#include <cstring>
25			#include <cstdio>
26
27			#include <sys/types.h>
28			#include <sys/socket.h>
29			#include <sys/poll.h>
30			#include <sys/wait.h>
31			#include <errno.h>
32			#include <time.h>
33			#include <unistd.h>
34	pcg	1.11	#include <fcntl.h>
35	pcg	1.9	#include <arpa/inet.h>
36			#include <netinet/in.h>
37	pcg	1.10	#include <netinet/ip_icmp.h>
38	pcg	1.1
39			#include "pidfile.h"
40
41			#include "connection.h"
42			#include "util.h"
43			#include "vpn.h"
44
45			/////////////////////////////////////////////////////////////////////////////
46
47	pcg	1.2	const char *vpn::script_if_up ()
48	pcg	1.1	{
49			// the tunnel device mtu should be the physical mtu - overhead
50			// the tricky part is rounding to the cipher key blocksize
51			int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
52			mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
53			mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
54			mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
55
56			char *env;
57			asprintf (&env, "CONFBASE=%s", confbase);
58			putenv (env);
59			asprintf (&env, "NODENAME=%s", THISNODE->nodename);
60			putenv (env);
61			asprintf (&env, "NODEID=%d", THISNODE->id);
62			putenv (env);
63			asprintf (&env, "IFNAME=%s", tap->interface ());
64			putenv (env);
65			asprintf (&env, "MTU=%d", mtu);
66			putenv (env);
67			asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
68			0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
69			THISNODE->id & 0xff);
70			putenv (env);
71
72			return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
73			}
74
75			int
76			vpn::setup ()
77			{
78	pcg	1.8	ipv4_fd = -1;
79	pcg	1.1
80	pcg	1.8	if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
81	pcg	1.1	{
82	pcg	1.8	ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
83	pcg	1.1
84	pcg	1.8	if (ipv4_fd < 0)
85	pcg	1.1	return -1;
86
87	pcg	1.11	fcntl (ipv4_fd, F_SETFL, O_NONBLOCK);
88
89	pcg	1.1	#ifdef IP_MTU_DISCOVER
90			// this I really consider a linux bug. I am neither connected
91			// nor do I fragment myself. Linux still sets DF and doesn't
92			// fragment for me sometimes.
93			{
94			int oval = IP_PMTUDISC_DONT;
95	pcg	1.8	setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
96	pcg	1.1	}
97			#endif
98
99	pcg	1.9	sockinfo si (THISNODE, PROT_IPv4);
100
101			if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
102			{
103			slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
104			exit (1);
105			}
106
107	pcg	1.8	ipv4_ev_watcher.start (ipv4_fd, POLLIN);
108	pcg	1.1	}
109
110	pcg	1.8	udpv4_fd = -1;
111
112			if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
113	pcg	1.1	{
114	pcg	1.8	udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
115	pcg	1.1
116	pcg	1.8	if (udpv4_fd < 0)
117	pcg	1.1	return -1;
118
119	pcg	1.11	fcntl (udpv4_fd, F_SETFL, O_NONBLOCK);
120
121	pcg	1.8	// standard daemon practise...
122			{
123			int oval = 1;
124			setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
125			}
126
127	pcg	1.9	#ifdef IP_MTU_DISCOVER
128			// this I really consider a linux bug. I am neither connected
129			// nor do I fragment myself. Linux still sets DF and doesn't
130			// fragment for me sometimes.
131			{
132			int oval = IP_PMTUDISC_DONT;
133			setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
134			}
135			#endif
136
137	pcg	1.8	sockinfo si (THISNODE, PROT_UDPv4);
138	pcg	1.2
139	pcg	1.8	if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
140	pcg	1.1	{
141	pcg	1.8	slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
142	pcg	1.1	exit (1);
143			}
144
145	pcg	1.9	udpv4_ev_watcher.start (udpv4_fd, POLLIN);
146			}
147
148			icmpv4_fd = -1;
149
150			#if ENABLE_ICMP
151			if (THISNODE->protocols & PROT_ICMPv4)
152			{
153			icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);
154
155			if (icmpv4_fd < 0)
156			return -1;
157
158	pcg	1.11	fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK);
159
160	pcg	1.9	#ifdef ICMP_FILTER
161			{
162			icmp_filter oval;
163			oval.data = 0xffffffff;
164			if (::conf.icmp_type < 32)
165			oval.data &= ~(1 << ::conf.icmp_type);
166
167			setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
168			}
169			#endif
170
171	pcg	1.1	#ifdef IP_MTU_DISCOVER
172			// this I really consider a linux bug. I am neither connected
173			// nor do I fragment myself. Linux still sets DF and doesn't
174			// fragment for me sometimes.
175			{
176			int oval = IP_PMTUDISC_DONT;
177	pcg	1.8	setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
178	pcg	1.1	}
179			#endif
180
181	pcg	1.9	sockinfo si (THISNODE, PROT_ICMPv4);
182
183			if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
184			{
185			slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
186			exit (1);
187			}
188
189			icmpv4_ev_watcher.start (icmpv4_fd, POLLIN);
190	pcg	1.1	}
191	pcg	1.9	#endif
192	pcg	1.1
193	pcg	1.8	tcpv4_fd = -1;
194
195	pcg	1.2	#if ENABLE_TCP
196	pcg	1.8	if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
197	pcg	1.2	{
198			tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
199
200			if (tcpv4_fd < 0)
201			return -1;
202
203	pcg	1.11	fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK);
204
205	pcg	1.3	// standard daemon practise...
206			{
207			int oval = 1;
208			setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
209			}
210
211	pcg	1.2	sockinfo si (THISNODE, PROT_TCPv4);
212
213			if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
214			{
215			slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
216			exit (1);
217			}
218
219			if (listen (tcpv4_fd, 5))
220			{
221			slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
222			exit (1);
223			}
224
225	pcg	1.3	tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
226	pcg	1.2	}
227			#endif
228
229	pcg	1.1	tap = new tap_device ();
230			if (!tap) //D this, of course, never catches
231			{
232			slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
233			exit (1);
234			}
235
236			run_script (run_script_cb (this, &vpn::script_if_up), true);
237
238			tap_ev_watcher.start (tap->fd, POLLIN);
239
240			reconnect_all ();
241
242			return 0;
243			}
244
245	pcg	1.5	// send a vpn packet out to other hosts
246	pcg	1.7	bool
247	pcg	1.5	vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
248			{
249			switch (si.prot)
250			{
251			case PROT_IPv4:
252	pcg	1.7	return send_ipv4_packet (pkt, si, tos);
253	pcg	1.5
254			case PROT_UDPv4:
255	pcg	1.7	return send_udpv4_packet (pkt, si, tos);
256	pcg	1.5
257			#if ENABLE_TCP
258			case PROT_TCPv4:
259	pcg	1.7	return send_tcpv4_packet (pkt, si, tos);
260	pcg	1.5	#endif
261
262	pcg	1.9	#if ENABLE_ICMP
263			case PROT_ICMPv4:
264			return send_icmpv4_packet (pkt, si, tos);
265			#endif
266
267	pcg	1.5	default:
268			slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
269	pcg	1.7	return false;
270	pcg	1.5	}
271			}
272
273	pcg	1.7	bool
274	pcg	1.1	vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
275			{
276			setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
277			sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
278	pcg	1.7
279			return true;
280	pcg	1.1	}
281
282	pcg	1.9	static u16
283			ipv4_checksum (u16 *data, unsigned int len)
284			{
285			// use 32 bit accumulator and fold back carry bits at the end
286			u32 sum = 0;
287
288			while (len > 1)
289			{
290			sum += *data++;
291			len -= 2;
292			}
293
294			// odd byte left?
295			if (len)
296			sum += (u8 )data;
297
298			// add back carry bits
299			sum = (sum >> 16) + (sum & 0xffff); // lo += hi
300			sum += (sum >> 16); // carry
301
302			return ~sum;
303			}
304
305			bool
306			vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
307			{
308			setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
309
310			pkt->unshift_hdr (4);
311
312			icmphdr hdr = (icmphdr )&((*pkt)[0]);
313			hdr->type = ::conf.icmp_type;
314			hdr->code = 255;
315			hdr->checksum = 0;
316			hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
317
318			sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
319
320			return true;
321			}
322
323	pcg	1.7	bool
324	pcg	1.1	vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
325			{
326			setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
327			sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
328	pcg	1.7
329			return true;
330	pcg	1.1	}
331
332			void
333			vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
334			{
335			unsigned int src = pkt->src ();
336			unsigned int dst = pkt->dst ();
337
338			slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
339			(const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
340
341			if (src == 0 \|\| src > conns.size ()
342			\|\| dst > conns.size ()
343			\|\| pkt->typ () >= vpn_packet::PT_MAX)
344			slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
345			(const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
346	pcg	1.6	else if (dst > conns.size ())
347			slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
348			(const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
349	pcg	1.1	else
350			{
351			connection *c = conns[src - 1];
352
353			if (dst == 0 && !THISNODE->routerprio)
354			slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
355			c->conf->nodename, (const char *)rsi);
356			else if (dst != 0 && dst != THISNODE->id)
357	pcg	1.6	{
358			if (THISNODE->routerprio)
359			// the tos setting gets lost here. who cares.
360			conns[dst - 1]->inject_vpn_packet (pkt);
361			else
362			slog (L_WARN,
363			_("%s(%s): forwarding request (=> %s), but we are no router"),
364			c->conf->nodename, (const char *)rsi,
365			conns[dst - 1]->conf->nodename);
366			}
367	pcg	1.1	else
368			c->recv_vpn_packet (pkt, rsi);
369			}
370			}
371
372			void
373	pcg	1.9	vpn::ipv4_ev (io_watcher &w, short revents)
374	pcg	1.1	{
375			if (revents & (POLLIN \| POLLERR))
376			{
377			vpn_packet *pkt = new vpn_packet;
378			struct sockaddr_in sa;
379			socklen_t sa_len = sizeof (sa);
380			int len;
381
382	pcg	1.5	len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
383	pcg	1.1
384	pcg	1.9	sockinfo si(sa, PROT_IPv4);
385	pcg	1.1
386			if (len > 0)
387			{
388			pkt->len = len;
389
390	pcg	1.9	// raw sockets deliver the ipv4, but don't expect it on sends
391			// this is slow, but...
392			pkt->skip_hdr (IP_OVERHEAD);
393
394	pcg	1.1	recv_vpn_packet (pkt, si);
395			}
396			else
397			{
398			// probably ECONNRESET or somesuch
399	pcg	1.9	slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
400	pcg	1.1	}
401
402			delete pkt;
403			}
404			else if (revents & POLLHUP)
405			{
406			// this cannot ;) happen on udp sockets
407	pcg	1.9	slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
408	pcg	1.1	exit (1);
409			}
410			else
411			{
412			slog (L_ERR,
413			_("FATAL: unknown revents %08x in socket, terminating\n"),
414			revents);
415			exit (1);
416			}
417			}
418
419			void
420	pcg	1.9	vpn::icmpv4_ev (io_watcher &w, short revents)
421	pcg	1.1	{
422			if (revents & (POLLIN \| POLLERR))
423			{
424			vpn_packet *pkt = new vpn_packet;
425			struct sockaddr_in sa;
426			socklen_t sa_len = sizeof (sa);
427			int len;
428
429	pcg	1.5	len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
430	pcg	1.1
431	pcg	1.9	sockinfo si(sa, PROT_ICMPv4);
432	pcg	1.1
433			if (len > 0)
434			{
435			pkt->len = len;
436
437	pcg	1.9	icmphdr hdr = (icmphdr )&((*pkt)[IP_OVERHEAD]);
438
439			if (hdr->type == ::conf.icmp_type
440			&& hdr->code == 255)
441			{
442			// raw sockets deliver the ipv4, but don't expect it on sends
443			// this is slow, but...
444			pkt->skip_hdr (ICMP_OVERHEAD);
445
446			recv_vpn_packet (pkt, si);
447			}
448			}
449			else
450			{
451			// probably ECONNRESET or somesuch
452			slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
453			}
454
455			delete pkt;
456			}
457			else if (revents & POLLHUP)
458			{
459			// this cannot ;) happen on udp sockets
460			slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
461			exit (1);
462			}
463			else
464			{
465			slog (L_ERR,
466			_("FATAL: unknown revents %08x in socket, terminating\n"),
467			revents);
468			exit (1);
469			}
470			}
471
472			void
473			vpn::udpv4_ev (io_watcher &w, short revents)
474			{
475			if (revents & (POLLIN \| POLLERR))
476			{
477			vpn_packet *pkt = new vpn_packet;
478			struct sockaddr_in sa;
479			socklen_t sa_len = sizeof (sa);
480			int len;
481
482			len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);
483
484			sockinfo si(sa, PROT_UDPv4);
485
486			if (len > 0)
487			{
488			pkt->len = len;
489	pcg	1.1
490			recv_vpn_packet (pkt, si);
491			}
492			else
493			{
494			// probably ECONNRESET or somesuch
495	pcg	1.9	slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
496	pcg	1.1	}
497
498			delete pkt;
499			}
500			else if (revents & POLLHUP)
501			{
502			// this cannot ;) happen on udp sockets
503	pcg	1.9	slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
504	pcg	1.1	exit (1);
505			}
506			else
507			{
508			slog (L_ERR,
509			_("FATAL: unknown revents %08x in socket, terminating\n"),
510			revents);
511			exit (1);
512			}
513			}
514	pcg	1.2
515			void
516	pcg	1.3	vpn::tap_ev (io_watcher &w, short revents)
517	pcg	1.1	{
518			if (revents & POLLIN)
519			{
520			/* process data */
521			tap_packet *pkt;
522
523			pkt = tap->recv ();
524
525			int dst = mac2id (pkt->dst);
526			int src = mac2id (pkt->src);
527
528			if (src != THISNODE->id)
529			{
530			slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
531			exit (1);
532			}
533
534			if (dst == THISNODE->id)
535			{
536			slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
537			exit (1);
538			}
539
540			if (dst > conns.size ())
541			slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
542			else
543			{
544			if (dst)
545			{
546			// unicast
547			if (dst != THISNODE->id)
548			conns[dst - 1]->inject_data_packet (pkt);
549			}
550			else
551			{
552			// broadcast, first check router, then self, then english
553			connection *router = find_router ();
554
555			if (router)
556			router->inject_data_packet (pkt, true);
557			else
558			for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
559			if ((*c)->conf != THISNODE)
560			(*c)->inject_data_packet (pkt);
561			}
562			}
563
564			delete pkt;
565			}
566			else if (revents & (POLLHUP \| POLLERR))
567			{
568			slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
569			exit (1);
570			}
571			else
572			abort ();
573			}
574
575			void
576	pcg	1.3	vpn::event_cb (time_watcher &w)
577	pcg	1.1	{
578			if (events)
579			{
580			if (events & EVENT_SHUTDOWN)
581			{
582			slog (L_INFO, _("preparing shutdown..."));
583
584			shutdown_all ();
585
586			remove_pid (pidfilename);
587
588			slog (L_INFO, _("terminating"));
589
590			exit (0);
591			}
592
593			if (events & EVENT_RECONNECT)
594			{
595			slog (L_INFO, _("forced reconnect"));
596
597			reconnect_all ();
598			}
599
600			events = 0;
601			}
602
603	pcg	1.3	w.at = TSTAMP_CANCEL;
604	pcg	1.1	}
605
606			void
607			vpn::shutdown_all ()
608			{
609			for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
610			(*c)->shutdown ();
611			}
612
613			void
614			vpn::reconnect_all ()
615			{
616			for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
617			delete *c;
618
619			conns.clear ();
620
621			connection_init ();
622
623			for (configuration::node_vector::iterator i = conf.nodes.begin ();
624			i != conf.nodes.end (); ++i)
625			{
626			connection *conn = new connection (this);
627
628			conn->conf = *i;
629			conns.push_back (conn);
630
631			conn->establish_connection ();
632			}
633			}
634
635			connection *vpn::find_router ()
636			{
637	pcg	1.12	u32 prio = 1;
638	pcg	1.1	connection *router = 0;
639
640			for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
641			{
642			connection c = i;
643
644	pcg	1.12	if (c->conf->routerprio >= prio
645	pcg	1.11	&& c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
646			&& c->ictx && c->octx
647			&& c->conf != THISNODE // redundant, since ictx==octx==0 always on thisnode
648			&& (!THISNODE->routerprio
649			\|\| c->conf->routerprio <= THISNODE->routerprio))
650	pcg	1.1	{
651			prio = c->conf->routerprio;
652			router = c;
653			}
654			}
655
656			return router;
657			}
658
659	pcg	1.7	void vpn::send_connect_request (int id)
660	pcg	1.1	{
661			connection *c = find_router ();
662
663			if (c)
664	pcg	1.7	c->send_connect_request (id);
665			else
666			// no router found, aggressively connect to all routers
667			for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
668			if ((*i)->conf->routerprio)
669			(*i)->establish_connection ();
670	pcg	1.1	}
671
672			void
673			connection::dump_status ()
674			{
675			slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
676			slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
677			connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
678			slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
679			(long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
680			slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
681			(long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
682			}
683
684			void
685			vpn::dump_status ()
686			{
687			slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
688
689			for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
690			(*c)->dump_status ();
691
692			slog (L_NOTICE, _("END status dump"));
693			}
694
695			vpn::vpn (void)
696	pcg	1.9	: event (this, &vpn::event_cb)
697			, udpv4_ev_watcher (this, &vpn::udpv4_ev)
698			, ipv4_ev_watcher (this, &vpn::ipv4_ev)
699	pcg	1.2	#if ENABLE_TCP
700	pcg	1.9	, tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
701			#endif
702			#if ENABLE_ICMP
703			, icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
704	pcg	1.2	#endif
705	pcg	1.9	, tap_ev_watcher (this, &vpn::tap_ev)
706	pcg	1.1	{
707			}
708
709			vpn::~vpn ()
710			{
711			}
712