mainloop.c

   1 /*
   2  * OpenConnect (SSL + DTLS) VPN client
   3  *
   4  * Copyright © 2008-2011 Intel Corporation.
   5  *
   6  * Author: David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * version 2.1, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to:
  19  *
  20  *   Free Software Foundation, Inc.
  21  *   51 Franklin Street, Fifth Floor,
  22  *   Boston, MA 02110-1301 USA
  23  */
  24
  25 #include <errno.h>
  26 #include <poll.h>
  27 #include <limits.h>
  28 #include <sys/select.h>
  29 #include <signal.h>
  30 #include <unistd.h>
  31 #include <string.h>
  32
  33 #include "openconnect-internal.h"
  34
  35 void queue_packet(struct pkt **q, struct pkt *new)
  36 {
  37         while (*q)
  38                 q = &(*q)->next;
  39
  40         new->next = NULL;
  41         *q = new;
  42 }
  43
  44 int queue_new_packet(struct pkt **q, void *buf, int len)
  45 {
  46         struct pkt *new = malloc(sizeof(struct pkt) + len);
  47         if (!new)
  48                 return -ENOMEM;
  49
  50         new->len = len;
  51         new->next = NULL;
  52         memcpy(new->data, buf, len);
  53         queue_packet(q, new);
  54         return 0;
  55 }
  56
  57 int killed;
  58
  59 static void handle_sigint(int sig)
  60 {
  61         killed = sig;
  62 }
  63
  64 int vpn_mainloop(struct openconnect_info *vpninfo)
  65 {
  66         struct sigaction sa;
  67         memset(&sa, 0, sizeof(sa));
  68         sa.sa_handler = handle_sigint;
  69
  70         sigaction(SIGTERM, &sa, NULL);
  71         sigaction(SIGINT, &sa, NULL);
  72         sigaction(SIGHUP, &sa, NULL);
  73
  74         while (!vpninfo->quit_reason) {
  75                 int did_work = 0;
  76                 int timeout = INT_MAX;
  77                 struct timeval tv;
  78                 fd_set rfds, wfds, efds;
  79
  80 #ifdef HAVE_DTLS
  81                 if (vpninfo->new_dtls_ssl)
  82                         dtls_try_handshake(vpninfo);
  83
  84                 if (vpninfo->dtls_attempt_period && !vpninfo->dtls_ssl && !vpninfo->new_dtls_ssl &&
  85                     vpninfo->new_dtls_started + vpninfo->dtls_attempt_period < time(NULL)) {
  86                         vpn_progress(vpninfo, PRG_TRACE, _("Attempt new DTLS connection\n"));
  87                         connect_dtls_socket(vpninfo);
  88                 }
  89                 if (vpninfo->dtls_ssl)
  90                         did_work += dtls_mainloop(vpninfo, &timeout);
  91 #endif
  92                 if (vpninfo->quit_reason)
  93                         break;
  94
  95                 did_work += cstp_mainloop(vpninfo, &timeout);
  96                 if (vpninfo->quit_reason)
  97                         break;
  98
  99                 /* Tun must be last because it will set/clear its bit
 100                    in the select_rfds according to the queue length */
 101                 did_work += tun_mainloop(vpninfo, &timeout);
 102                 if (vpninfo->quit_reason)
 103                         break;
 104
 105                 if (killed) {
 106                         if (killed == SIGHUP)
 107                                 vpninfo->quit_reason = "Client received SIGHUP";
 108                         else if (killed == SIGINT)
 109                                 vpninfo->quit_reason = "Client received SIGINT";
 110                         else
 111                                 vpninfo->quit_reason = "Client killed";
 112                         break;
 113                 }
 114
 115                 if (did_work)
 116                         continue;
 117
 118                 vpn_progress(vpninfo, PRG_TRACE,
 119                              _("No work to do; sleeping for %d ms...\n"), timeout);
 120                 memcpy(&rfds, &vpninfo->select_rfds, sizeof(rfds));
 121                 memcpy(&wfds, &vpninfo->select_wfds, sizeof(wfds));
 122                 memcpy(&efds, &vpninfo->select_efds, sizeof(efds));
 123
 124                 tv.tv_sec = timeout / 1000;
 125                 tv.tv_usec = (timeout % 1000) * 1000;
 126
 127                 select(vpninfo->select_nfds, &rfds, &wfds, &efds, &tv);
 128         }
 129
 130         cstp_bye(vpninfo, vpninfo->quit_reason);
 131
 132         shutdown_tun(vpninfo);
 133         return 0;
 134 }
 135
 136 /* Called when the socket is unwritable, to get the deadline for DPD.
 137    Returns 1 if DPD deadline has already arrived. */
 138 int ka_stalled_dpd_time(struct keepalive_info *ka, int *timeout)
 139 {
 140         time_t now, due;
 141
 142         if (!ka->dpd)
 143                 return 0;
 144
 145         time(&now);
 146         due = ka->last_rx + (2 * ka->dpd);
 147
 148         if (now > due)
 149                 return 1;
 150
 151         if (*timeout > (due - now) * 1000)
 152                 *timeout = (due - now) * 1000;
 153
 154         return 0;
 155 }
 156
 157
 158 int keepalive_action(struct keepalive_info *ka, int *timeout)
 159 {
 160         time_t now = time(NULL);
 161
 162         if (ka->rekey) {
 163                 time_t due = ka->last_rekey + ka->rekey;
 164
 165                 if (now >= due)
 166                         return KA_REKEY;
 167
 168                 if (*timeout > (due - now) * 1000)
 169                         *timeout = (due - now) * 1000;
 170         }
 171
 172         /* DPD is bidirectional -- PKT 3 out, PKT 4 back */
 173         if (ka->dpd) {
 174                 time_t due = ka->last_rx + ka->dpd;
 175                 time_t overdue = ka->last_rx + (2 * ka->dpd);
 176
 177                 /* Peer didn't respond */
 178                 if (now > overdue)
 179                         return KA_DPD_DEAD;
 180
 181                 /* If we already have DPD outstanding, don't flood. Repeat by
 182                    all means, but only after half the DPD period. */
 183                 if (ka->last_dpd > ka->last_rx)
 184                         due = ka->last_dpd + ka->dpd / 2;
 185
 186                 /* We haven't seen a packet from this host for $DPD seconds.
 187                    Prod it to see if it's still alive */
 188                 if (now >= due) {
 189                         ka->last_dpd = now;
 190                         return KA_DPD;
 191                 }
 192                 if (*timeout > (due - now) * 1000)
 193                         *timeout = (due - now) * 1000;
 194         }
 195
 196         /* Keepalive is just client -> server */
 197         if (ka->keepalive) {
 198                 time_t due = ka->last_tx + ka->keepalive;
 199
 200                 /* If we haven't sent anything for $KEEPALIVE seconds, send a
 201                    dummy packet (which the server will discard) */
 202                 if (now >= due)
 203                         return KA_KEEPALIVE;
 204
 205                 if (*timeout > (due - now) * 1000)
 206                         *timeout = (due - now) * 1000;
 207         }
 208
 209         return KA_NONE;
 210 }