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 #include <string.h>
  33
  34 #include "openconnect.h"
  35
  36 void queue_packet(struct pkt **q, struct pkt *new)
  37 {
  38         while (*q)
  39                 q = &(*q)->next;
  40
  41         new->next = NULL;
  42         *q = new;
  43 }
  44
  45 int queue_new_packet(struct pkt **q, int type, void *buf, int len)
  46 {
  47         struct pkt *new = malloc(sizeof(struct pkt) + len);
  48         if (!new)
  49                 return -ENOMEM;
  50
  51         new->type = type;
  52         new->len = len;
  53         new->next = NULL;
  54         memcpy(new->data, buf, len);
  55         queue_packet(q, new);
  56         return 0;
  57 }
  58
  59 int killed;
  60
  61 static void handle_sigint(int sig)
  62 {
  63         killed = sig;
  64 }
  65
  66 int vpn_mainloop(struct openconnect_info *vpninfo)
  67 {
  68         struct sigaction sa;
  69         memset(&sa, 0, sizeof(sa));
  70         sa.sa_handler = handle_sigint;
  71
  72         sigaction(SIGINT, &sa, NULL);
  73         sigaction(SIGHUP, &sa, NULL);
  74
  75         while (!vpninfo->quit_reason) {
  76                 int did_work = 0;
  77                 int timeout = INT_MAX;
  78                 struct timeval tv;
  79                 fd_set rfds, wfds, efds;
  80
  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                         vpninfo->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
  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                 vpninfo->progress(vpninfo, PRG_TRACE,
 119                                   "Did no work; 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                 if (select(vpninfo->select_nfds, &rfds, &wfds, &efds, &tv) >= 0
 127                     && FD_ISSET(vpninfo->ssl_fd, &rfds)) {
 128                         char b;
 129                         if (recv(vpninfo->ssl_fd, &b, 1, MSG_PEEK) == 0) {
 130                                 /* Zero indicates EOF, which OpenSSL won't handle on read() */
 131                                 vpninfo->progress(vpninfo, PRG_ERR, "Server closed connection!\n");
 132                                 exit(1);
 133                         }
 134                 }
 135         }
 136
 137         cstp_bye(vpninfo, vpninfo->quit_reason);
 138
 139         if (vpninfo->vpnc_script) {
 140                 if (vpninfo->script_tun) {
 141                         kill(vpninfo->script_tun, SIGHUP);
 142                         close(vpninfo->tun_fd);
 143                 } else {
 144                         setenv("TUNDEV", vpninfo->ifname, 1);
 145                         setenv("reason", "disconnect", 1);
 146                         system(vpninfo->vpnc_script);
 147                 }
 148         }
 149
 150         return 0;
 151 }
 152
 153 /* Called when the socket is unwritable, to get the deadline for DPD.
 154    Returns 1 if DPD deadline has already arrived. */
 155 int ka_stalled_dpd_time(struct keepalive_info *ka, int *timeout)
 156 {
 157         time_t now, due;
 158
 159         if (!ka->dpd)
 160                 return 0;
 161
 162         time(&now);
 163         due = ka->last_rx + (2 * ka->dpd);
 164
 165         if (now > due)
 166                 return 1;
 167
 168         if (*timeout > (due - now) * 1000)
 169                 *timeout = (due - now) * 1000;
 170
 171         return 0;
 172 }
 173
 174
 175 int keepalive_action(struct keepalive_info *ka, int *timeout)
 176 {
 177         time_t now = time(NULL);
 178
 179         if (ka->rekey) {
 180                 time_t due = ka->last_rekey + ka->rekey;
 181
 182                 if (now >= due)
 183                         return KA_REKEY;
 184
 185                 if (*timeout > (due - now) * 1000)
 186                         *timeout = (due - now) * 1000;
 187         }
 188
 189         /* DPD is bidirectional -- PKT 3 out, PKT 4 back */
 190         if (ka->dpd) {
 191                 time_t due = ka->last_rx + ka->dpd;
 192                 time_t overdue = ka->last_rx + (2 * ka->dpd);
 193
 194                 /* Peer didn't respond */
 195                 if (now > overdue)
 196                         return KA_DPD_DEAD;
 197
 198                 /* If we already have DPD outstanding, don't flood. Repeat by
 199                    all means, but only after half the DPD period. */
 200                 if (ka->last_dpd > ka->last_rx)
 201                         due = ka->last_dpd + ka->dpd / 2;
 202
 203                 /* We haven't seen a packet from this host for $DPD seconds.
 204                    Prod it to see if it's still alive */
 205                 if (now >= due) {
 206                         ka->last_dpd = now;
 207                         return KA_DPD;
 208                 }
 209                 if (*timeout > (due - now) * 1000)
 210                         *timeout = (due - now) * 1000;
 211         }
 212
 213         /* Keepalive is just client -> server */
 214         if (ka->keepalive) {
 215                 time_t due = ka->last_tx + ka->keepalive;
 216
 217                 /* If we haven't sent anything for $KEEPALIVE seconds, send a
 218                    dummy packet (which the server will discard) */
 219                 if (now >= due)
 220                         return KA_KEEPALIVE;
 221
 222                 if (*timeout > (due - now) * 1000)
 223                         *timeout = (due - now) * 1000;
 224         }
 225
 226         return KA_NONE;
 227 }