diff options
Diffstat (limited to 'shared/n-dhcp4/src/n-dhcp4-client.c')
| -rw-r--r-- | shared/n-dhcp4/src/n-dhcp4-client.c | 56 |
1 files changed, 28 insertions, 28 deletions
diff --git a/shared/n-dhcp4/src/n-dhcp4-client.c b/shared/n-dhcp4/src/n-dhcp4-client.c index 4fa3d65d..6b015e81 100644 --- a/shared/n-dhcp4/src/n-dhcp4-client.c +++ b/shared/n-dhcp4/src/n-dhcp4-client.c @@ -388,14 +388,10 @@ _c_public_ int n_dhcp4_client_new(NDhcp4Client **clientp, NDhcp4ClientConfig *co return -errno; client->fd_timer = timerfd_create(CLOCK_BOOTTIME, TFD_CLOEXEC | TFD_NONBLOCK); - if (client->fd_timer < 0) { - if (errno != EINVAL) - return -errno; + if (client->fd_timer < 0 && errno == EINVAL) client->fd_timer = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK); - if (client->fd_timer < 0) - return -errno; - client->timerfd_is_monotonic = true; - } + if (client->fd_timer < 0) + return -errno; ev.data.u32 = N_DHCP4_CLIENT_EPOLL_TIMER; r = epoll_ctl(client->fd_epoll, EPOLL_CTL_ADD, client->fd_timer, &ev); @@ -498,41 +494,45 @@ int n_dhcp4_client_raise(NDhcp4Client *client, NDhcp4CEventNode **nodep, unsigne * must be called whenever a timeout on @client might have changed. */ void n_dhcp4_client_arm_timer(NDhcp4Client *client) { - uint64_t timeout = 0; + uint64_t now, offset, timeout = 0; int r; if (client->current_probe) n_dhcp4_client_probe_get_timeout(client->current_probe, &timeout); if (timeout != client->scheduled_timeout) { - uint64_t scheduled_timeout = timeout; - int flags = TFD_TIMER_ABSTIME; - - if ( timeout != 0 - && client->timerfd_is_monotonic) { - uint64_t now; - - /* the timerfd ticks with CLOCK_MONOTONIC. Calculate and set the relative - * timeout. */ - now = n_dhcp4_gettime(CLOCK_BOOTTIME); - if (timeout <= now) - timeout = 1; - else - timeout = timeout - now; - flags = 0; - } + /* + * Across our codebase, timeouts are specified as absolute + * timestamps on CLOCK_BOOTTIME. Unfortunately, there are + * systems with CLOCK_BOOTTIME support, but timerfd lacks it + * (in particular RHEL). Therefore, our timerfd might be on + * CLOCK_MONOTONIC. + * To account for this, we always schedule a relative timeout. + * We fetch the current time and then calculate the offset + * which we then schedule as relative timeout on the timerfd. + * This works regardless which clock the timerfd runs on. + * Once we no longer support CLOCK_MONOTONIC as fallback, we + * can simply switch to TFD_TIMER_ABSTIME here and specify + * `timeout` directly as value. + */ + now = n_dhcp4_gettime(CLOCK_BOOTTIME); + if (now >= timeout) + offset = 1; /* 0 would disarm the timerfd */ + else + offset = timeout - now; + r = timerfd_settime(client->fd_timer, - flags, + 0, &(struct itimerspec){ .it_value = { - .tv_sec = timeout / UINT64_C(1000000000), - .tv_nsec = timeout % UINT64_C(1000000000), + .tv_sec = offset / UINT64_C(1000000000), + .tv_nsec = offset % UINT64_C(1000000000), }, }, NULL); c_assert(r >= 0); - client->scheduled_timeout = scheduled_timeout; + client->scheduled_timeout = timeout; } } |