Use timespec timers to determine when select-timeout and timeout intervals

are exceeded.

Feedback from otto@, cheloha@

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index b45dc86..8ec981d 100644 (file)
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dhclient.c,v 1.710 2021/03/09 14:32:24 krw Exp $      */
+/*     $OpenBSD: dhclient.c,v 1.711 2021/03/11 15:30:49 krw Exp $      */
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -807,12 +807,18 @@ state_reboot(struct interface_info *ifi)
 void
 state_init(struct interface_info *ifi)
 {
+       const struct timespec   offer_intvl = {config->offer_interval, 0};
+       struct timespec         now;
+
        ifi->xid = arc4random();
        make_discover(ifi, ifi->active);
 
        ifi->destination.s_addr = INADDR_BROADCAST;
        ifi->state = S_SELECTING;
-       time(&ifi->first_sending);
+       clock_gettime(CLOCK_REALTIME, &now);
+       ifi->first_sending = now.tv_sec;
+       timespecadd(&now, &offer_intvl, &ifi->offer_timeout);
+       ifi->select_timeout = ifi->offer_timeout;
        ifi->interval = 0;
 
        send_discover(ifi);
@@ -892,10 +898,11 @@ void
 process_offer(struct interface_info *ifi, struct option_data *options,
     const char *src)
 {
+       const struct timespec    select_intvl = {config->select_interval, 0};
+       struct timespec          now, remaining;
        struct client_lease     *lease;
-       time_t                   cur_time, stop_selecting;
 
-       time(&cur_time);
+       clock_gettime(CLOCK_REALTIME, &now);
 
        lease = packet_to_lease(ifi, options);
        if (lease != NULL) {
@@ -903,6 +910,10 @@ process_offer(struct interface_info *ifi, struct option_data *options,
                        ifi->offer = lease;
                        free(ifi->offer_src);
                        ifi->offer_src = strdup(src);   /* NULL is OK */
+                       timespecadd(&now, &select_intvl, &ifi->select_timeout);
+                       if (timespeccmp(&ifi->select_timeout,
+                           &ifi->offer_timeout, >))
+                               ifi->select_timeout = ifi->offer_timeout;
                } else if (lease->address.s_addr ==
                    ifi->offer->address.s_addr) {
                        /* Decline duplicate offers. */
@@ -920,12 +931,16 @@ process_offer(struct interface_info *ifi, struct option_data *options,
                }
        }
 
-       /* Figure out when we're supposed to stop selecting. */
-       stop_selecting = ifi->first_sending + config->select_interval;
-       if (stop_selecting <= cur_time)
+       if (timespeccmp(&now, &ifi->select_timeout, >=))
                state_selecting(ifi);
-       else
-               set_timeout(ifi, stop_selecting - cur_time, state_selecting);
+       else {
+               timespecsub(&ifi->select_timeout, &now, &remaining);
+               if (remaining.tv_sec == 0 || remaining.tv_nsec > 500000000LL)
+                       remaining.tv_sec++;
+               log_debug("%s: waiting %lld seconds for better offers",
+                   log_procname, (long long)remaining.tv_sec);
+               set_timeout(ifi, remaining.tv_sec, state_selecting);
+       }
 }
 
 void
@@ -1378,9 +1393,13 @@ set_interval(struct interface_info *ifi, time_t cur_time)
                if (cur_time + interval > ifi->expiry)
                        interval = ifi->expiry - cur_time;
                break;
+       case S_SELECTING:
+               if (cur_time + interval > ifi->select_timeout.tv_sec)
+                       interval = ifi->select_timeout.tv_sec - cur_time;
+               break;
        case S_REQUESTING:
-               if (cur_time + interval > ifi->first_sending + config->offer_interval)
-                       interval = (ifi->first_sending + config->offer_interval) - cur_time;
+               if (cur_time + interval > ifi->offer_timeout.tv_sec)
+                       interval = ifi->offer_timeout.tv_sec - cur_time;
                break;
        default:
                break;
@@ -1420,7 +1439,7 @@ send_discover(struct interface_info *ifi)
        clock_gettime(CLOCK_REALTIME, &now);
        cur_time = now.tv_sec;
 
-       if (cur_time > ifi->first_sending + config->offer_interval) {
+       if (timespeccmp(&now, &ifi->offer_timeout, >=)) {
                state_panic(ifi);
                return;
        }
@@ -1514,7 +1533,7 @@ send_request(struct interface_info *ifi)
                }
                break;
        case S_REQUESTING:
-               if (interval > config->offer_interval)
+               if (timespeccmp(&now, &ifi->offer_timeout, >=))
                        ifi->state = S_INIT;
                else {
                        destination.sin_addr.s_addr = INADDR_BROADCAST;

diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index 08ac22f..692a693 100644 (file)
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dhcpd.h,v 1.296 2021/03/09 14:32:24 krw Exp $ */
+/*     $OpenBSD: dhcpd.h,v 1.297 2021/03/11 15:30:49 krw Exp $ */
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -141,6 +141,8 @@ struct interface_info {
        uint16_t                 secs;
        time_t                   first_sending;
        struct timespec          link_timeout;
+       struct timespec          offer_timeout;
+       struct timespec          select_timeout;
        enum dhcp_state          state;
        struct in_addr           destination;
        time_t                   interval;