From 164b8dd8e4be8a563cf18a1cdc2929a552dbfc34 Mon Sep 17 00:00:00 2001 From: Kevin Lund Date: Thu, 11 Jun 2020 14:11:17 -0700 Subject: [PATCH] wpa_supplicant: Add wpa_blacklist_update() This change adds the function wpa_blacklist_update(), which goes through all blacklist entries and deletes them if their blacklist expired over an hour ago. The purpose of this is to remove stale entries from the blacklist which likely do not reflect the current condition of device's network surroundings. This function is called whenever the blacklist is polled, meaning that the caller always gets an up-to-date reflection of the blacklist. Another solution to clearing the blacklist that was considered was to slowly reduce the counts of blacklist entries over time, and delete them if the counts dropped below 0. We decided to go with the current solution instead because an AP's "problematic" status is really a binary thing: either the AP is no longer problematic, or it's still causing us problems. So if we see any more problems within a reasonable amount of time, it makes sense to just keep the blacklist where it was since the AP is likely still undergoing the same issue. If we go a significant amount of time (semi-arbitrarily chosen as 1 hour) without any issues with an AP, it's reasonable to behave as if the AP is no longer undergoing the same issue. If we see more problems at a later time, we can start the blacklisting process fresh again, treating this as a brand new issue. Signed-off-by: Kevin Lund Signed-off-by: Brian Norris --- wpa_supplicant/blacklist.c | 41 ++++++++++++++++++++++++++++++++++++++ wpa_supplicant/blacklist.h | 1 + 2 files changed, 42 insertions(+) diff --git a/wpa_supplicant/blacklist.c b/wpa_supplicant/blacklist.c index c88a69acd..fa2ad11ee 100644 --- a/wpa_supplicant/blacklist.c +++ b/wpa_supplicant/blacklist.c @@ -26,6 +26,8 @@ struct wpa_blacklist * wpa_blacklist_get(struct wpa_supplicant *wpa_s, if (wpa_s == NULL || bssid == NULL) return NULL; + wpa_blacklist_update(wpa_s); + e = wpa_s->blacklist; while (e) { if (os_memcmp(e->bssid, bssid, ETH_ALEN) == 0) @@ -171,3 +173,42 @@ void wpa_blacklist_clear(struct wpa_supplicant *wpa_s) os_free(prev); } } + + +/** + * wpa_blacklist_update - Update the entries in the blacklist, + * deleting entries that have been expired for over an hour. + * @wpa_s: Pointer to wpa_supplicant data + */ +void wpa_blacklist_update(struct wpa_supplicant *wpa_s) +{ + struct wpa_blacklist *e, *prev = NULL; + struct os_reltime now; + + if (!wpa_s) + return; + + e = wpa_s->blacklist; + os_get_reltime(&now); + while (e) { + if (os_reltime_expired(&now, &e->blacklist_start, + e->timeout_secs + 3600)) { + struct wpa_blacklist *to_delete = e; + + if (prev) { + prev->next = e->next; + e = prev->next; + } else { + wpa_s->blacklist = e->next; + e = wpa_s->blacklist; + } + wpa_printf(MSG_INFO, "Removed BSSID " MACSTR + " from blacklist (expired)", + MAC2STR(to_delete->bssid)); + os_free(to_delete); + } else { + prev = e; + e = e->next; + } + } +} diff --git a/wpa_supplicant/blacklist.h b/wpa_supplicant/blacklist.h index 54ca6a37f..a1c60d5e6 100644 --- a/wpa_supplicant/blacklist.h +++ b/wpa_supplicant/blacklist.h @@ -28,5 +28,6 @@ int wpa_blacklist_add(struct wpa_supplicant *wpa_s, const u8 *bssid); int wpa_blacklist_del(struct wpa_supplicant *wpa_s, const u8 *bssid); int wpa_blacklist_is_blacklisted(struct wpa_supplicant *wpa_s, const u8 *bssid); void wpa_blacklist_clear(struct wpa_supplicant *wpa_s); +void wpa_blacklist_update(struct wpa_supplicant *wpa_s); #endif /* BLACKLIST_H */