| /* |
| * WPA Supplicant - background scan and roaming module: learn |
| * Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi> |
| * |
| * This software may be distributed under the terms of the BSD license. |
| * See README for more details. |
| */ |
| |
| #include "includes.h" |
| |
| #include "common.h" |
| #include "eloop.h" |
| #include "list.h" |
| #include "common/ieee802_11_defs.h" |
| #include "drivers/driver.h" |
| #include "config_ssid.h" |
| #include "wpa_supplicant_i.h" |
| #include "driver_i.h" |
| #include "scan.h" |
| #include "bgscan.h" |
| |
| struct bgscan_learn_bss { |
| struct dl_list list; |
| u8 bssid[ETH_ALEN]; |
| int freq; |
| u8 *neigh; /* num_neigh * ETH_ALEN buffer */ |
| size_t num_neigh; |
| }; |
| |
| struct bgscan_learn_data { |
| struct wpa_supplicant *wpa_s; |
| const struct wpa_ssid *ssid; |
| int scan_interval; |
| int signal_threshold; |
| int short_interval; /* use if signal < threshold */ |
| int long_interval; /* use if signal > threshold */ |
| struct os_reltime last_bgscan; |
| char *fname; |
| struct dl_list bss; |
| int *supp_freqs; |
| int probe_idx; |
| }; |
| |
| |
| static void bss_free(struct bgscan_learn_bss *bss) |
| { |
| os_free(bss->neigh); |
| os_free(bss); |
| } |
| |
| |
| static int bssid_in_array(u8 *array, size_t array_len, const u8 *bssid) |
| { |
| size_t i; |
| |
| if (array == NULL || array_len == 0) |
| return 0; |
| |
| for (i = 0; i < array_len; i++) { |
| if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| |
| static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss, |
| const u8 *bssid) |
| { |
| u8 *n; |
| |
| if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0) |
| return; |
| if (bssid_in_array(bss->neigh, bss->num_neigh, bssid)) |
| return; |
| |
| n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN); |
| if (n == NULL) |
| return; |
| |
| os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN); |
| bss->neigh = n; |
| bss->num_neigh++; |
| } |
| |
| |
| static struct bgscan_learn_bss * bgscan_learn_get_bss( |
| struct bgscan_learn_data *data, const u8 *bssid) |
| { |
| struct bgscan_learn_bss *bss; |
| |
| dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) { |
| if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0) |
| return bss; |
| } |
| return NULL; |
| } |
| |
| |
| static int bgscan_learn_load(struct bgscan_learn_data *data) |
| { |
| FILE *f; |
| char buf[128]; |
| struct bgscan_learn_bss *bss; |
| |
| if (data->fname == NULL) |
| return 0; |
| |
| f = fopen(data->fname, "r"); |
| if (f == NULL) |
| return 0; |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s", |
| data->fname); |
| |
| if (fgets(buf, sizeof(buf), f) == NULL || |
| os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) { |
| wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s", |
| data->fname); |
| fclose(f); |
| return -1; |
| } |
| |
| while (fgets(buf, sizeof(buf), f)) { |
| if (os_strncmp(buf, "BSS ", 4) == 0) { |
| bss = os_zalloc(sizeof(*bss)); |
| if (!bss) |
| continue; |
| if (hwaddr_aton(buf + 4, bss->bssid) < 0) { |
| bss_free(bss); |
| continue; |
| } |
| bss->freq = atoi(buf + 4 + 18); |
| dl_list_add(&data->bss, &bss->list); |
| wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS " |
| "entry: " MACSTR " freq=%d", |
| MAC2STR(bss->bssid), bss->freq); |
| } |
| |
| if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) { |
| u8 addr[ETH_ALEN]; |
| |
| if (hwaddr_aton(buf + 9, addr) < 0) |
| continue; |
| bss = bgscan_learn_get_bss(data, addr); |
| if (bss == NULL) |
| continue; |
| if (hwaddr_aton(buf + 9 + 18, addr) < 0) |
| continue; |
| |
| bgscan_learn_add_neighbor(bss, addr); |
| } |
| } |
| |
| fclose(f); |
| return 0; |
| } |
| |
| |
| static void bgscan_learn_save(struct bgscan_learn_data *data) |
| { |
| FILE *f; |
| struct bgscan_learn_bss *bss; |
| |
| if (data->fname == NULL) |
| return; |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s", |
| data->fname); |
| |
| f = fopen(data->fname, "w"); |
| if (f == NULL) |
| return; |
| fprintf(f, "wpa_supplicant-bgscan-learn\n"); |
| |
| dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) { |
| fprintf(f, "BSS " MACSTR " %d\n", |
| MAC2STR(bss->bssid), bss->freq); |
| } |
| |
| dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) { |
| size_t i; |
| for (i = 0; i < bss->num_neigh; i++) { |
| fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n", |
| MAC2STR(bss->bssid), |
| MAC2STR(bss->neigh + i * ETH_ALEN)); |
| } |
| } |
| |
| fclose(f); |
| } |
| |
| |
| static int in_array(int *array, int val) |
| { |
| int i; |
| |
| if (array == NULL) |
| return 0; |
| |
| for (i = 0; array[i]; i++) { |
| if (array[i] == val) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| |
| static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data, |
| size_t *count) |
| { |
| struct bgscan_learn_bss *bss; |
| int *freqs = NULL, *n; |
| |
| *count = 0; |
| |
| dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) { |
| if (in_array(freqs, bss->freq)) |
| continue; |
| n = os_realloc_array(freqs, *count + 2, sizeof(int)); |
| if (n == NULL) |
| return freqs; |
| freqs = n; |
| freqs[*count] = bss->freq; |
| (*count)++; |
| freqs[*count] = 0; |
| } |
| |
| return freqs; |
| } |
| |
| |
| static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data, |
| int *freqs, size_t count) |
| { |
| int idx, *n; |
| |
| if (data->supp_freqs == NULL) |
| return freqs; |
| |
| idx = data->probe_idx; |
| do { |
| if (!in_array(freqs, data->supp_freqs[idx])) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq " |
| "%u", data->supp_freqs[idx]); |
| data->probe_idx = idx + 1; |
| if (data->supp_freqs[data->probe_idx] == 0) |
| data->probe_idx = 0; |
| n = os_realloc_array(freqs, count + 2, sizeof(int)); |
| if (n == NULL) |
| return freqs; |
| freqs = n; |
| freqs[count] = data->supp_freqs[idx]; |
| count++; |
| freqs[count] = 0; |
| break; |
| } |
| |
| idx++; |
| if (data->supp_freqs[idx] == 0) |
| idx = 0; |
| } while (idx != data->probe_idx); |
| |
| return freqs; |
| } |
| |
| |
| static void bgscan_learn_timeout(void *eloop_ctx, void *timeout_ctx) |
| { |
| struct bgscan_learn_data *data = eloop_ctx; |
| struct wpa_supplicant *wpa_s = data->wpa_s; |
| struct wpa_driver_scan_params params; |
| int *freqs = NULL; |
| size_t count, i; |
| char msg[100], *pos; |
| |
| os_memset(¶ms, 0, sizeof(params)); |
| params.num_ssids = 1; |
| params.ssids[0].ssid = data->ssid->ssid; |
| params.ssids[0].ssid_len = data->ssid->ssid_len; |
| if (data->ssid->scan_freq) |
| params.freqs = data->ssid->scan_freq; |
| else { |
| freqs = bgscan_learn_get_freqs(data, &count); |
| wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have " |
| "been seen on %u channels", (unsigned int) count); |
| freqs = bgscan_learn_get_probe_freq(data, freqs, count); |
| |
| msg[0] = '\0'; |
| pos = msg; |
| for (i = 0; freqs && freqs[i]; i++) { |
| int ret; |
| ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d", |
| freqs[i]); |
| if (os_snprintf_error(msg + sizeof(msg) - pos, ret)) |
| break; |
| pos += ret; |
| } |
| pos[0] = '\0'; |
| wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s", |
| msg); |
| params.freqs = freqs; |
| } |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan"); |
| if (wpa_supplicant_trigger_scan(wpa_s, ¶ms)) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan"); |
| eloop_register_timeout(data->scan_interval, 0, |
| bgscan_learn_timeout, data, NULL); |
| } else |
| os_get_reltime(&data->last_bgscan); |
| os_free(freqs); |
| } |
| |
| |
| static int bgscan_learn_get_params(struct bgscan_learn_data *data, |
| const char *params) |
| { |
| const char *pos; |
| |
| if (params == NULL) |
| return 0; |
| |
| data->short_interval = atoi(params); |
| |
| pos = os_strchr(params, ':'); |
| if (pos == NULL) |
| return 0; |
| pos++; |
| data->signal_threshold = atoi(pos); |
| pos = os_strchr(pos, ':'); |
| if (pos == NULL) { |
| wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval " |
| "for high signal"); |
| return -1; |
| } |
| pos++; |
| data->long_interval = atoi(pos); |
| pos = os_strchr(pos, ':'); |
| if (pos) { |
| pos++; |
| data->fname = os_strdup(pos); |
| } |
| |
| return 0; |
| } |
| |
| |
| static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s) |
| { |
| struct hostapd_hw_modes *modes; |
| int i, j, *freqs = NULL, *n; |
| size_t count = 0; |
| |
| modes = wpa_s->hw.modes; |
| if (modes == NULL) |
| return NULL; |
| |
| for (i = 0; i < wpa_s->hw.num_modes; i++) { |
| for (j = 0; j < modes[i].num_channels; j++) { |
| if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED) |
| continue; |
| /* some hw modes (e.g. 11b & 11g) contain same freqs */ |
| if (in_array(freqs, modes[i].channels[j].freq)) |
| continue; |
| n = os_realloc_array(freqs, count + 2, sizeof(int)); |
| if (n == NULL) |
| continue; |
| |
| freqs = n; |
| freqs[count] = modes[i].channels[j].freq; |
| count++; |
| freqs[count] = 0; |
| } |
| } |
| |
| return freqs; |
| } |
| |
| |
| static void * bgscan_learn_init(struct wpa_supplicant *wpa_s, |
| const char *params, |
| const struct wpa_ssid *ssid) |
| { |
| struct bgscan_learn_data *data; |
| |
| data = os_zalloc(sizeof(*data)); |
| if (data == NULL) |
| return NULL; |
| dl_list_init(&data->bss); |
| data->wpa_s = wpa_s; |
| data->ssid = ssid; |
| if (bgscan_learn_get_params(data, params) < 0) { |
| os_free(data->fname); |
| os_free(data); |
| return NULL; |
| } |
| if (data->short_interval <= 0) |
| data->short_interval = 30; |
| if (data->long_interval <= 0) |
| data->long_interval = 30; |
| |
| if (bgscan_learn_load(data) < 0) { |
| os_free(data->fname); |
| os_free(data); |
| return NULL; |
| } |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d " |
| "Short bgscan interval %d Long bgscan interval %d", |
| data->signal_threshold, data->short_interval, |
| data->long_interval); |
| |
| if (data->signal_threshold && |
| wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) { |
| wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable " |
| "signal strength monitoring"); |
| } |
| |
| data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s); |
| data->scan_interval = data->short_interval; |
| if (data->signal_threshold) { |
| /* Poll for signal info to set initial scan interval */ |
| struct wpa_signal_info siginfo; |
| if (wpa_drv_signal_poll(wpa_s, &siginfo) == 0 && |
| siginfo.current_signal >= data->signal_threshold) |
| data->scan_interval = data->long_interval; |
| } |
| |
| eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout, |
| data, NULL); |
| |
| /* |
| * This function is called immediately after an association, so it is |
| * reasonable to assume that a scan was completed recently. This makes |
| * us skip an immediate new scan in cases where the current signal |
| * level is below the bgscan threshold. |
| */ |
| os_get_reltime(&data->last_bgscan); |
| |
| return data; |
| } |
| |
| |
| static void bgscan_learn_deinit(void *priv) |
| { |
| struct bgscan_learn_data *data = priv; |
| struct bgscan_learn_bss *bss, *n; |
| |
| bgscan_learn_save(data); |
| eloop_cancel_timeout(bgscan_learn_timeout, data, NULL); |
| if (data->signal_threshold) |
| wpa_drv_signal_monitor(data->wpa_s, 0, 0); |
| os_free(data->fname); |
| dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss, |
| list) { |
| dl_list_del(&bss->list); |
| bss_free(bss); |
| } |
| os_free(data->supp_freqs); |
| os_free(data); |
| } |
| |
| |
| static int bgscan_learn_bss_match(struct bgscan_learn_data *data, |
| struct wpa_scan_res *bss) |
| { |
| const u8 *ie; |
| |
| ie = wpa_scan_get_ie(bss, WLAN_EID_SSID); |
| if (ie == NULL) |
| return 0; |
| |
| if (data->ssid->ssid_len != ie[1] || |
| os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0) |
| return 0; /* SSID mismatch */ |
| |
| return 1; |
| } |
| |
| |
| static int bgscan_learn_notify_scan(void *priv, |
| struct wpa_scan_results *scan_res) |
| { |
| struct bgscan_learn_data *data = priv; |
| size_t i, j; |
| #define MAX_BSS 50 |
| u8 bssid[MAX_BSS * ETH_ALEN]; |
| size_t num_bssid = 0; |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification"); |
| |
| eloop_cancel_timeout(bgscan_learn_timeout, data, NULL); |
| eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout, |
| data, NULL); |
| |
| for (i = 0; i < scan_res->num; i++) { |
| struct wpa_scan_res *res = scan_res->res[i]; |
| if (!bgscan_learn_bss_match(data, res)) |
| continue; |
| |
| if (num_bssid < MAX_BSS) { |
| os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid, |
| ETH_ALEN); |
| num_bssid++; |
| } |
| } |
| wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan " |
| "results", (unsigned int) num_bssid); |
| |
| for (i = 0; i < scan_res->num; i++) { |
| struct wpa_scan_res *res = scan_res->res[i]; |
| struct bgscan_learn_bss *bss; |
| |
| if (!bgscan_learn_bss_match(data, res)) |
| continue; |
| |
| bss = bgscan_learn_get_bss(data, res->bssid); |
| if (bss && bss->freq != res->freq) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS " |
| MACSTR " freq %d -> %d", |
| MAC2STR(res->bssid), bss->freq, res->freq); |
| bss->freq = res->freq; |
| } else if (!bss) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR |
| " freq=%d", MAC2STR(res->bssid), res->freq); |
| bss = os_zalloc(sizeof(*bss)); |
| if (!bss) |
| continue; |
| os_memcpy(bss->bssid, res->bssid, ETH_ALEN); |
| bss->freq = res->freq; |
| dl_list_add(&data->bss, &bss->list); |
| } |
| |
| for (j = 0; j < num_bssid; j++) { |
| u8 *addr = bssid + j * ETH_ALEN; |
| bgscan_learn_add_neighbor(bss, addr); |
| } |
| } |
| |
| /* |
| * A more advanced bgscan could process scan results internally, select |
| * the BSS and request roam if needed. This sample uses the existing |
| * BSS/ESS selection routine. Change this to return 1 if selection is |
| * done inside the bgscan module. |
| */ |
| |
| return 0; |
| } |
| |
| |
| static void bgscan_learn_notify_beacon_loss(void *priv) |
| { |
| wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss"); |
| /* TODO: speed up background scanning */ |
| } |
| |
| |
| static void bgscan_learn_notify_signal_change(void *priv, int above, |
| int current_signal, |
| int current_noise, |
| int current_txrate) |
| { |
| struct bgscan_learn_data *data = priv; |
| int scan = 0; |
| struct os_reltime now; |
| |
| if (data->short_interval == data->long_interval || |
| data->signal_threshold == 0) |
| return; |
| |
| wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed " |
| "(above=%d current_signal=%d current_noise=%d " |
| "current_txrate=%d)", above, current_signal, |
| current_noise, current_txrate); |
| if (data->scan_interval == data->long_interval && !above) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan " |
| "interval"); |
| data->scan_interval = data->short_interval; |
| os_get_reltime(&now); |
| if (now.sec > data->last_bgscan.sec + 1) |
| scan = 1; |
| } else if (data->scan_interval == data->short_interval && above) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan " |
| "interval"); |
| data->scan_interval = data->long_interval; |
| eloop_cancel_timeout(bgscan_learn_timeout, data, NULL); |
| eloop_register_timeout(data->scan_interval, 0, |
| bgscan_learn_timeout, data, NULL); |
| } else if (!above) { |
| /* |
| * Signal dropped further 4 dB. Request a new scan if we have |
| * not yet scanned in a while. |
| */ |
| os_get_reltime(&now); |
| if (now.sec > data->last_bgscan.sec + 10) |
| scan = 1; |
| } |
| |
| if (scan) { |
| wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan"); |
| eloop_cancel_timeout(bgscan_learn_timeout, data, NULL); |
| eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL); |
| } |
| } |
| |
| |
| const struct bgscan_ops bgscan_learn_ops = { |
| .name = "learn", |
| .init = bgscan_learn_init, |
| .deinit = bgscan_learn_deinit, |
| .notify_scan = bgscan_learn_notify_scan, |
| .notify_beacon_loss = bgscan_learn_notify_beacon_loss, |
| .notify_signal_change = bgscan_learn_notify_signal_change, |
| }; |