mainloop.c

   1 /*
   2  * OpenConnect (SSL + DTLS) VPN client
   3  *
   4  * Copyright © 2008 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 <arpa/inet.h>
  31 #include <unistd.h>
  32
  33 #include "openconnect.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, int type, void *buf, int len)
  45 {
  46         struct pkt *new = malloc(sizeof(struct pkt) + len);
  47         if (!new)
  48                 return -ENOMEM;
  49
  50         new->type = type;
  51         new->len = len;
  52         new->next = NULL;
  53         memcpy(new->data, buf, len);
  54         queue_packet(q, new);
  55         return 0;
  56 }
  57
  58 int killed;
  59
  60 static void handle_sigint(int sig)
  61 {
  62         killed = sig;
  63 }
  64
  65 int vpn_mainloop(struct openconnect_info *vpninfo)
  66 {
  67         struct sigaction sa;
  68         memset(&sa, 0, sizeof(sa));
  69         sa.sa_handler = handle_sigint;
  70
  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                 if (vpninfo->new_dtls_ssl)
  81                         dtls_try_handshake(vpninfo);
  82
  83                 if (vpninfo->dtls_attempt_period && !vpninfo->dtls_ssl && !vpninfo->new_dtls_ssl &&
  84                     vpninfo->new_dtls_started + vpninfo->dtls_attempt_period < time(NULL)) {
  85                         vpninfo->progress(vpninfo, PRG_TRACE, "Attempt new DTLS connection\n");
  86                         connect_dtls_socket(vpninfo);
  87                 }
  88                 if (vpninfo->dtls_ssl)
  89                         did_work += dtls_mainloop(vpninfo, &timeout);
  90
  91                 if (vpninfo->quit_reason)
  92                         break;
  93
  94                 did_work += cstp_mainloop(vpninfo, &timeout);
  95                 if (vpninfo->quit_reason)
  96                         break;
  97
  98                 /* Tun must be last because it will set/clear its bit
  99                    in the select_rfds according to the queue length */
 100                 did_work += tun_mainloop(vpninfo, &timeout);
 101                 if (vpninfo->quit_reason)
 102                         break;
 103
 104                 if (killed) {
 105                         if (killed == SIGHUP)
 106                                 vpninfo->quit_reason = "Client received SIGHUP";
 107                         else if (killed == SIGINT)
 108                                 vpninfo->quit_reason = "Client received SIGINT";
 109                         else
 110                                 vpninfo->quit_reason = "Client killed";
 111                         break;
 112                 }
 113
 114                 if (did_work)
 115                         continue;
 116
 117                 vpninfo->progress(vpninfo, PRG_TRACE,
 118                                   "Did no work; sleeping for %d ms...\n", timeout);
 119                 memcpy(&rfds, &vpninfo->select_rfds, sizeof(rfds));
 120                 memcpy(&wfds, &vpninfo->select_wfds, sizeof(wfds));
 121                 memcpy(&efds, &vpninfo->select_efds, sizeof(efds));
 122
 123                 tv.tv_sec = timeout / 1000;
 124                 tv.tv_usec = (timeout % 1000) * 1000;
 125                 if (select(vpninfo->select_nfds, &rfds, &wfds, &efds, &tv) >= 0
 126                     && FD_ISSET(vpninfo->ssl_fd, &rfds)) {
 127                         char b;
 128                         if (recv(vpninfo->ssl_fd, &b, 1, MSG_PEEK) == 0) {
 129                                 /* Zero indicates EOF, which OpenSSL won't handle on read() */
 130                                 vpninfo->progress(vpninfo, PRG_ERR, "Server closed connection!\n");
 131                                 exit(1);
 132                         }
 133                 }
 134         }
 135
 136         cstp_bye(vpninfo, vpninfo->quit_reason);
 137
 138         if (vpninfo->vpnc_script) {
 139                 if (vpninfo->script_tun) {
 140                         kill(vpninfo->script_tun, SIGHUP);
 141                         close(vpninfo->tun_fd);
 142                 } else {
 143                         setenv("TUNDEV", vpninfo->ifname, 1);
 144                         setenv("reason", "disconnect", 1);
 145                         system(vpninfo->vpnc_script);
 146                 }
 147         }
 148
 149         return 0;
 150 }
 151
 152 /* Called when the socket is unwritable, to get the deadline for DPD.
 153    Returns 1 if DPD deadline has already arrived. */
 154 int ka_stalled_dpd_time(struct keepalive_info *ka, int *timeout)
 155 {
 156         time_t now, due;
 157
 158         if (!ka->dpd)
 159                 return 0;
 160
 161         time(&now);
 162         due = ka->last_rx + (2 * ka->dpd);
 163
 164         if (now > due)
 165                 return 1;
 166
 167         if (*timeout > (due - now) * 1000)
 168                 *timeout = (due - now) * 1000;
 169
 170         return 0;
 171 }
 172
 173
 174 int keepalive_action(struct keepalive_info *ka, int *timeout)
 175 {
 176         time_t now = time(NULL);
 177
 178         if (ka->rekey) {
 179                 time_t due = ka->last_rekey + ka->rekey;
 180
 181                 if (now >= due)
 182                         return KA_REKEY;
 183
 184                 if (*timeout > (due - now) * 1000)
 185                         *timeout = (due - now) * 1000;
 186         }
 187
 188         /* DPD is bidirectional -- PKT 3 out, PKT 4 back */
 189         if (ka->dpd) {
 190                 time_t due = ka->last_rx + ka->dpd;
 191                 time_t overdue = ka->last_rx + (2 * ka->dpd);
 192
 193                 /* Peer didn't respond */
 194                 if (now > overdue)
 195                         return KA_DPD_DEAD;
 196
 197                 /* If we already have DPD outstanding, don't flood. Repeat by
 198                    all means, but only after half the DPD period. */
 199                 if (ka->last_dpd > ka->last_rx)
 200                         due = ka->last_dpd + ka->dpd / 2;
 201
 202                 /* We haven't seen a packet from this host for $DPD seconds.
 203                    Prod it to see if it's still alive */
 204                 if (now >= due) {
 205                         ka->last_dpd = now;
 206                         return KA_DPD;
 207                 }
 208                 if (*timeout > (due - now) * 1000)
 209                         *timeout = (due - now) * 1000;
 210         }
 211
 212         /* Keepalive is just client -> server */
 213         if (ka->keepalive) {
 214                 time_t due = ka->last_tx + ka->keepalive;
 215
 216                 /* If we haven't sent anything for $KEEPALIVE seconds, send a
 217                    dummy packet (which the server will discard) */
 218                 if (now >= due)
 219                         return KA_KEEPALIVE;
 220
 221                 if (*timeout > (due - now) * 1000)
 222                         *timeout = (due - now) * 1000;
 223         }
 224
 225         return KA_NONE;
 226 }