mainloop.c

   1 /*
   2  * Open AnyConnect (SSL + DTLS) client
   3  *
   4  * © 2008 David Woodhouse <dwmw2@infradead.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation; either version 2.1 of
   9  * the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to:
  18  *
  19  *   Free Software Foundation, Inc.
  20  *   51 Franklin Street, Fifth Floor,
  21  *   Boston, MA 02110-1301 USA
  22  */
  23
  24 #include <errno.h>
  25 #include <poll.h>
  26 #include <limits.h>
  27 #include <sys/select.h>
  28 #include <signal.h>
  29 #include <arpa/inet.h>
  30 #include <unistd.h>
  31
  32 #include "openconnect.h"
  33
  34 void queue_packet(struct pkt **q, struct pkt *new)
  35 {
  36         while (*q)
  37                 q = &(*q)->next;
  38
  39         new->next = NULL;
  40         *q = new;
  41 }
  42
  43 int queue_new_packet(struct pkt **q, int type, void *buf, int len)
  44 {
  45         struct pkt *new = malloc(sizeof(struct pkt) + len);
  46         if (!new)
  47                 return -ENOMEM;
  48
  49         new->type = type;
  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 static 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(SIGINT, &sa, NULL);
  71         sigaction(SIGHUP, &sa, NULL);
  72
  73         while (!vpninfo->quit_reason) {
  74                 int did_work = 0;
  75                 int timeout = INT_MAX;
  76                 struct timeval tv;
  77                 fd_set rfds, wfds, efds;
  78
  79                 if (vpninfo->new_dtls_ssl)
  80                         dtls_try_handshake(vpninfo);
  81
  82                 if (vpninfo->dtls_attempt_period && !vpninfo->dtls_ssl && !vpninfo->new_dtls_ssl &&
  83                     vpninfo->new_dtls_started + vpninfo->dtls_attempt_period < time(NULL)) {
  84                         vpninfo->progress(vpninfo, PRG_TRACE, "Attempt new DTLS connection\n");
  85                         connect_dtls_socket(vpninfo);
  86                 }
  87                 if (vpninfo->dtls_ssl)
  88                         did_work += dtls_mainloop(vpninfo, &timeout);
  89
  90                 if (vpninfo->quit_reason)
  91                         break;
  92
  93                 did_work += cstp_mainloop(vpninfo, &timeout);
  94                 if (vpninfo->quit_reason)
  95                         break;
  96
  97                 did_work += tun_mainloop(vpninfo, &timeout);
  98                 if (vpninfo->quit_reason)
  99                         break;
 100
 101                 if (killed) {
 102                         if (killed == SIGHUP)
 103                                 vpninfo->quit_reason = "Client received SIGHUP";
 104                         else if (killed == SIGINT)
 105                                 vpninfo->quit_reason = "Client received SIGINT";
 106                         else
 107                                 vpninfo->quit_reason = "Client killed";
 108                         break;
 109                 }
 110
 111                 if (did_work)
 112                         continue;
 113
 114                 vpninfo->progress(vpninfo, PRG_TRACE,
 115                                   "Did no work; sleeping for %d ms...\n", timeout);
 116                 memcpy(&rfds, &vpninfo->select_rfds, sizeof(rfds));
 117                 memcpy(&wfds, &vpninfo->select_wfds, sizeof(wfds));
 118                 memcpy(&efds, &vpninfo->select_efds, sizeof(efds));
 119
 120                 tv.tv_sec = timeout / 1000;
 121                 tv.tv_usec = (timeout * 1000) % 1000000;
 122                 select(vpninfo->select_nfds, &rfds, &wfds, &efds, &tv);
 123                 if (FD_ISSET(vpninfo->ssl_fd, &efds)) {
 124                         vpninfo->progress(vpninfo, PRG_ERR, "Server closed connection!\n");
 125                         /* OpenSSL doesn't seem to cope properly with this... */
 126                         exit(1);
 127                 }
 128         }
 129
 130         cstp_bye(vpninfo, vpninfo->quit_reason);
 131         vpninfo->progress(vpninfo, PRG_INFO, "Sent quit message: %s\n", vpninfo->quit_reason);
 132
 133         if (vpninfo->vpnc_script) {
 134                 if (vpninfo->script_tun) {
 135                         kill(vpninfo->script_tun, SIGHUP);
 136                         close(vpninfo->tun_fd);
 137                 } else {
 138                         setenv("TUNDEV", vpninfo->ifname, 1);
 139                         setenv("reason", "disconnect", 1);
 140                         system(vpninfo->vpnc_script);
 141                 }
 142         }
 143
 144         return 0;
 145 }
 146
 147 /* Called when the socket is unwritable, to get the deadline for DPD.
 148    Returns 1 if DPD deadline has already arrived. */
 149 int ka_stalled_dpd_time(struct keepalive_info *ka, int *timeout)
 150 {
 151         time_t now, due;
 152
 153         if (!ka->dpd)
 154                 return 0;
 155
 156         time(&now);
 157         due = ka->last_rx + (2 * ka->dpd);
 158
 159         if (now > due)
 160                 return 1;
 161
 162         if (*timeout > (due - now) * 1000)
 163                 *timeout = (due - now) * 1000;
 164
 165         return 0;
 166 }
 167
 168
 169 int keepalive_action(struct keepalive_info *ka, int *timeout)
 170 {
 171         time_t now = time(NULL);
 172
 173         if (ka->rekey) {
 174                 time_t due = ka->last_rekey + ka->rekey;
 175
 176                 if (now >= due)
 177                         return KA_REKEY;
 178
 179                 if (*timeout > (due - now) * 1000)
 180                         *timeout = (due - now) * 1000;
 181         }
 182
 183         /* DPD is bidirectional -- PKT 3 out, PKT 4 back */
 184         if (ka->dpd) {
 185                 time_t due = ka->last_rx + ka->dpd;
 186                 time_t overdue = ka->last_rx + (2 * ka->dpd);
 187
 188                 /* Peer didn't respond */
 189                 if (now > overdue)
 190                         return KA_DPD_DEAD;
 191
 192                 /* If we already have DPD outstanding, don't flood. Repeat by
 193                    all means, but only after half the DPD period. */
 194                 if (ka->last_dpd > ka->last_rx)
 195                         due = ka->last_dpd + ka->dpd / 2;
 196
 197                 /* We haven't seen a packet from this host for $DPD seconds.
 198                    Prod it to see if it's still alive */
 199                 if (now >= due) {
 200                         ka->last_dpd = now;
 201                         return KA_DPD;
 202                 }
 203                 if (*timeout > (due - now) * 1000)
 204                         *timeout = (due - now) * 1000;
 205         }
 206
 207         /* Keepalive is just client -> server */
 208         if (ka->keepalive) {
 209                 time_t due = ka->last_tx + ka->keepalive;
 210
 211                 /* If we haven't sent anything for $KEEPALIVE seconds, send a
 212                    dummy packet (which the server will discard) */
 213                 if (now >= due)
 214                         return KA_KEEPALIVE;
 215
 216                 if (*timeout > (due - now) * 1000)
 217                         *timeout = (due - now) * 1000;
 218         }
 219
 220         return KA_NONE;
 221 }