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                 /* Tun must be last because it will set/clear its bit
  98                    in the select_rfds according to the queue length */
  99                 did_work += tun_mainloop(vpninfo, &timeout);
 100                 if (vpninfo->quit_reason)
 101                         break;
 102
 103                 if (killed) {
 104                         if (killed == SIGHUP)
 105                                 vpninfo->quit_reason = "Client received SIGHUP";
 106                         else if (killed == SIGINT)
 107                                 vpninfo->quit_reason = "Client received SIGINT";
 108                         else
 109                                 vpninfo->quit_reason = "Client killed";
 110                         break;
 111                 }
 112
 113                 if (did_work)
 114                         continue;
 115
 116                 vpninfo->progress(vpninfo, PRG_TRACE,
 117                                   "Did no work; sleeping for %d ms...\n", timeout);
 118                 memcpy(&rfds, &vpninfo->select_rfds, sizeof(rfds));
 119                 memcpy(&wfds, &vpninfo->select_wfds, sizeof(wfds));
 120                 memcpy(&efds, &vpninfo->select_efds, sizeof(efds));
 121
 122                 tv.tv_sec = timeout / 1000;
 123                 tv.tv_usec = (timeout * 1000) % 1000000;
 124                 if (select(vpninfo->select_nfds, &rfds, &wfds, &efds, &tv) >= 0
 125                     && FD_ISSET(vpninfo->ssl_fd, &efds)) {
 126                         /* OpenSSL doesn't seem to cope properly with this... */
 127                         vpninfo->progress(vpninfo, PRG_ERR, "Server closed connection!\n");
 128                         exit(1);
 129                 }
 130         }
 131
 132         cstp_bye(vpninfo, vpninfo->quit_reason);
 133
 134         if (vpninfo->vpnc_script) {
 135                 if (vpninfo->script_tun) {
 136                         kill(vpninfo->script_tun, SIGHUP);
 137                         close(vpninfo->tun_fd);
 138                 } else {
 139                         setenv("TUNDEV", vpninfo->ifname, 1);
 140                         setenv("reason", "disconnect", 1);
 141                         system(vpninfo->vpnc_script);
 142                 }
 143         }
 144
 145         return 0;
 146 }
 147
 148 /* Called when the socket is unwritable, to get the deadline for DPD.
 149    Returns 1 if DPD deadline has already arrived. */
 150 int ka_stalled_dpd_time(struct keepalive_info *ka, int *timeout)
 151 {
 152         time_t now, due;
 153
 154         if (!ka->dpd)
 155                 return 0;
 156
 157         time(&now);
 158         due = ka->last_rx + (2 * ka->dpd);
 159
 160         if (now > due)
 161                 return 1;
 162
 163         if (*timeout > (due - now) * 1000)
 164                 *timeout = (due - now) * 1000;
 165
 166         return 0;
 167 }
 168
 169
 170 int keepalive_action(struct keepalive_info *ka, int *timeout)
 171 {
 172         time_t now = time(NULL);
 173
 174         if (ka->rekey) {
 175                 time_t due = ka->last_rekey + ka->rekey;
 176
 177                 if (now >= due)
 178                         return KA_REKEY;
 179
 180                 if (*timeout > (due - now) * 1000)
 181                         *timeout = (due - now) * 1000;
 182         }
 183
 184         /* DPD is bidirectional -- PKT 3 out, PKT 4 back */
 185         if (ka->dpd) {
 186                 time_t due = ka->last_rx + ka->dpd;
 187                 time_t overdue = ka->last_rx + (2 * ka->dpd);
 188
 189                 /* Peer didn't respond */
 190                 if (now > overdue)
 191                         return KA_DPD_DEAD;
 192
 193                 /* If we already have DPD outstanding, don't flood. Repeat by
 194                    all means, but only after half the DPD period. */
 195                 if (ka->last_dpd > ka->last_rx)
 196                         due = ka->last_dpd + ka->dpd / 2;
 197
 198                 /* We haven't seen a packet from this host for $DPD seconds.
 199                    Prod it to see if it's still alive */
 200                 if (now >= due) {
 201                         ka->last_dpd = now;
 202                         return KA_DPD;
 203                 }
 204                 if (*timeout > (due - now) * 1000)
 205                         *timeout = (due - now) * 1000;
 206         }
 207
 208         /* Keepalive is just client -> server */
 209         if (ka->keepalive) {
 210                 time_t due = ka->last_tx + ka->keepalive;
 211
 212                 /* If we haven't sent anything for $KEEPALIVE seconds, send a
 213                    dummy packet (which the server will discard) */
 214                 if (now >= due)
 215                         return KA_KEEPALIVE;
 216
 217                 if (*timeout > (due - now) * 1000)
 218                         *timeout = (due - now) * 1000;
 219         }
 220
 221         return KA_NONE;
 222 }