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station: Move roam triggering & scanning code

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Move the roam initiation (signal loss, ap directed roaming) and scanning
details into station from device.  Certain device functions have been
exposed temporarily to make this possible.
This commit is contained in:
Denis Kenzior 2018-09-04 13:48:18 -05:00
parent 966cad3696
commit 575d0fa554
4 changed files with 612 additions and 580 deletions
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601
src/device.c
View File

@ -26,7 +26,6 @@
#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <linux/if_ether.h>
#include <ell/ell.h>
@ -55,9 +54,6 @@ struct device {
struct network *connected_network;
struct l_dbus_message *connect_pending;
struct l_dbus_message *disconnect_pending;
struct timespec roam_min_time;
struct l_timeout *roam_trigger_timeout;
uint32_t roam_scan_id;
uint8_t preauth_bssid[ETH_ALEN];
struct signal_agent *signal_agent;
@ -68,10 +64,6 @@ struct device {
bool powered : 1;
bool scanning : 1;
bool autoconnect : 1;
bool preparing_roam : 1;
bool signal_low : 1;
bool roam_no_orig_ap : 1;
bool ap_directed_roaming : 1;
uint32_t ap_roam_watch;
};
@ -85,8 +77,6 @@ struct signal_agent {
static struct l_queue *device_list;
static uint32_t netdev_watch;
static void device_roam_timeout_rearm(struct device *device, int seconds);
static void device_netdev_event(struct netdev *netdev, enum netdev_event event,
void *user_data);
@ -255,14 +245,7 @@ static void device_reset_connection_state(struct device *device)
station->state == STATION_STATE_ROAMING)
network_disconnected(network);
l_timeout_remove(device->roam_trigger_timeout);
device->roam_trigger_timeout = NULL;
device->preparing_roam = false;
device->signal_low = false;
device->roam_min_time.tv_sec = 0;
if (device->roam_scan_id)
scan_cancel(device->index, device->roam_scan_id);
station_roam_state_clear(station);
device->connected_bss = NULL;
station->connected_bss = NULL;
@ -275,7 +258,7 @@ static void device_reset_connection_state(struct device *device)
IWD_NETWORK_INTERFACE, "Connected");
}
static void device_disassociated(struct device *device)
void device_disassociated(struct device *device)
{
l_debug("%d", device->index);
@ -303,30 +286,6 @@ static void device_disconnect_event(struct device *device)
device_disassociated(device);
}
static void device_roam_failed(struct device *device)
{
struct station *station = device->station;
/*
* If we're still connected to the old BSS, only clear preparing_roam
* and reattempt in 60 seconds if signal level is still low at that
* time. Otherwise (we'd already started negotiating with the
* transition target, preparing_roam is false, state is roaming) we
* are now disconnected.
*/
l_debug("%d", device->index);
device->preparing_roam = false;
device->roam_no_orig_ap = false;
device->ap_directed_roaming = false;
if (station->state == STATION_STATE_ROAMING)
device_disassociated(device);
else if (device->signal_low)
device_roam_timeout_rearm(device, 60);
}
static void device_reassociate_cb(struct netdev *netdev,
enum netdev_result result,
void *user_data)
@ -340,17 +299,10 @@ static void device_reassociate_cb(struct netdev *netdev,
return;
if (result == NETDEV_RESULT_OK) {
/*
* New signal high/low notification should occur on the next
* beacon from new AP.
*/
device->signal_low = false;
device->roam_min_time.tv_sec = 0;
device->roam_no_orig_ap = false;
station_roamed(station);
device_enter_state(device, STATION_STATE_CONNECTED);
} else
device_roam_failed(device);
station_roam_failed(station);
}
static void device_fast_transition_cb(struct netdev *netdev,
@ -366,17 +318,10 @@ static void device_fast_transition_cb(struct netdev *netdev,
return;
if (result == NETDEV_RESULT_OK) {
/*
* New signal high/low notification should occur on the next
* beacon from new AP.
*/
device->signal_low = false;
device->roam_min_time.tv_sec = 0;
device->roam_no_orig_ap = false;
station_roamed(station);
device_enter_state(device, STATION_STATE_CONNECTED);
} else
device_roam_failed(device);
station_roam_failed(station);
}
static void device_transition_reassociate(struct device *device,
@ -389,14 +334,13 @@ static void device_transition_reassociate(struct device *device,
new_hs, device_netdev_event,
device_reassociate_cb, device) < 0) {
handshake_state_free(new_hs);
device_roam_failed(device);
station_roam_failed(station);
return;
}
device->connected_bss = bss;
station->connected_bss = bss;
device->preparing_roam = false;
station->preparing_roam = false;
device_enter_state(device, STATION_STATE_ROAMING);
}
@ -420,15 +364,14 @@ static void device_preauthenticate_cb(struct netdev *netdev,
l_debug("%d, result: %d", device->index, result);
if (!device->preparing_roam || result == NETDEV_RESULT_ABORTED)
if (!station->preparing_roam || result == NETDEV_RESULT_ABORTED)
return;
bss = l_queue_find(device->station->bss_list, bss_match_bssid,
device->preauth_bssid);
if (!bss) {
l_error("Roam target BSS not found");
device_roam_failed(device);
station_roam_failed(station);
return;
}
@ -436,7 +379,7 @@ static void device_preauthenticate_cb(struct netdev *netdev,
if (!new_hs) {
l_error("device_handshake_setup failed");
device_roam_failed(device);
station_roam_failed(station);
return;
}
@ -474,7 +417,7 @@ static void device_preauthenticate_cb(struct netdev *netdev,
device_transition_reassociate(device, bss, new_hs);
}
static void device_transition_start(struct device *device, struct scan_bss *bss)
void device_transition_start(struct device *device, struct scan_bss *bss)
{
struct handshake_state *hs = netdev_get_handshake(device->netdev);
struct network *connected = device_get_connected_network(device);
@ -488,7 +431,7 @@ static void device_transition_start(struct device *device, struct scan_bss *bss)
util_address_to_string(bss->addr));
/* Reset AP roam flag, at this point the roaming behaves the same */
device->ap_directed_roaming = false;
station->ap_directed_roaming = false;
if (hs->mde)
ie_parse_mobility_domain_from_data(hs->mde, hs->mde[1] + 2,
@ -508,13 +451,13 @@ static void device_transition_start(struct device *device, struct scan_bss *bss)
*/
if (netdev_fast_transition(device->netdev, bss,
device_fast_transition_cb) < 0) {
device_roam_failed(device);
station_roam_failed(station);
return;
}
device->connected_bss = bss;
station->connected_bss = bss;
device->preparing_roam = false;
station->preparing_roam = false;
device_enter_state(device, STATION_STATE_ROAMING);
return;
@ -530,7 +473,7 @@ static void device_transition_start(struct device *device, struct scan_bss *bss)
* the current association."
*/
if (security == SECURITY_8021X &&
!device->roam_no_orig_ap &&
!station->roam_no_orig_ap &&
scan_bss_get_rsn_info(device->connected_bss,
&cur_rsne) >= 0 &&
scan_bss_get_rsn_info(bss, &target_rsne) >= 0 &&
@ -555,402 +498,13 @@ static void device_transition_start(struct device *device, struct scan_bss *bss)
new_hs = station_handshake_setup(station, connected, bss);
if (!new_hs) {
l_error("device_handshake_setup failed in reassociation");
device_roam_failed(device);
station_roam_failed(station);
return;
}
device_transition_reassociate(device, bss, new_hs);
}
static void device_roam_scan_triggered(int err, void *user_data)
{
struct device *device = user_data;
if (err) {
device_roam_failed(device);
return;
}
/*
* Do not update the Scanning property as we won't be updating the
* list of networks.
*/
}
static bool device_roam_scan_notify(uint32_t wiphy_id, uint32_t ifindex,
int err, struct l_queue *bss_list,
void *userdata)
{
struct device *device = userdata;
struct network *network = device->connected_network;
struct handshake_state *hs = netdev_get_handshake(device->netdev);
struct scan_bss *bss;
struct scan_bss *best_bss = NULL;
double best_bss_rank = 0.0;
static const double RANK_FT_FACTOR = 1.3;
uint16_t mdid;
enum security orig_security, security;
bool seen = false;
if (err) {
device_roam_failed(device);
return false;
}
/*
* Do not call device_set_scan_results because this may have been
* a partial scan. We could at most update the current networks' BSS
* list in its device->networks entry.
*/
orig_security = network_get_security(network);
if (hs->mde)
ie_parse_mobility_domain_from_data(hs->mde, hs->mde[1] + 2,
&mdid, NULL, NULL);
/*
* BSSes in the bss_list come already ranked with their initial
* association preference rank value. We only need to add preference
* for BSSes that are within the FT Mobility Domain so as to favor
* Fast Roaming, if it is supported.
*/
while ((bss = l_queue_pop_head(bss_list))) {
double rank;
struct ie_rsn_info info;
int r;
/* Skip the BSS we are connected to if doing an AP roam */
if (device->ap_directed_roaming && !memcmp(bss->addr,
device->connected_bss->addr, 6))
goto next;
/* Skip result if it is not part of the ESS */
if (bss->ssid_len != hs->ssid_len ||
memcmp(bss->ssid, hs->ssid, hs->ssid_len))
goto next;
memset(&info, 0, sizeof(info));
r = scan_bss_get_rsn_info(bss, &info);
if (r < 0) {
if (r != -ENOENT)
goto next;
security = security_determine(bss->capability, NULL);
} else
security = security_determine(bss->capability, &info);
if (security != orig_security)
goto next;
seen = true;
if (!wiphy_can_connect(device->wiphy, bss))
goto next;
rank = bss->rank;
if (hs->mde && bss->mde_present && l_get_le16(bss->mde) == mdid)
rank *= RANK_FT_FACTOR;
if (rank > best_bss_rank) {
if (best_bss)
scan_bss_free(best_bss);
best_bss = bss;
best_bss_rank = rank;
continue;
}
next:
scan_bss_free(bss);
}
l_queue_destroy(bss_list, NULL);
if (!seen)
goto fail_free_bss;
/* See if we have anywhere to roam to */
if (!best_bss || scan_bss_addr_eq(best_bss, device->connected_bss))
goto fail_free_bss;
bss = network_bss_find_by_addr(network, best_bss->addr);
if (bss) {
scan_bss_free(best_bss);
best_bss = bss;
} else {
network_bss_add(network, best_bss);
l_queue_push_tail(device->station->bss_list, best_bss);
}
device_transition_start(device, best_bss);
return true;
fail_free_bss:
if (best_bss)
scan_bss_free(best_bss);
device_roam_failed(device);
return true;
}
static void device_roam_scan_destroy(void *userdata)
{
struct device *device = userdata;
device->roam_scan_id = 0;
}
static void device_roam_scan(struct device *device,
struct scan_freq_set *freq_set)
{
struct scan_parameters params = { .freqs = freq_set, .flush = true };
if (device->connected_network)
/* Use direct probe request */
params.ssid = network_get_ssid(device->connected_network);
device->roam_scan_id = scan_active_full(device->index, &params,
device_roam_scan_triggered,
device_roam_scan_notify, device,
device_roam_scan_destroy);
if (!device->roam_scan_id)
device_roam_failed(device);
}
static uint32_t device_freq_from_neighbor_report(const uint8_t *country,
struct ie_neighbor_report_info *info, enum scan_band *out_band)
{
enum scan_band band;
uint32_t freq;
if (info->oper_class == 0) {
/*
* Some Cisco APs report all operating class values as 0
* in the Neighbor Report Responses. Work around this by
* using the most likely operating class for the channel
* number as the 2.4GHz and 5GHz bands happen to mostly
* use channels in two disjoint ranges.
*/
if (info->channel_num >= 1 && info->channel_num <= 14)
band = SCAN_BAND_2_4_GHZ;
else if (info->channel_num >= 36 && info->channel_num <= 169)
band = SCAN_BAND_5_GHZ;
else {
l_debug("Ignored: 0 oper class with an unusual "
"channel number");
return 0;
}
} else {
band = scan_oper_class_to_band(country, info->oper_class);
if (!band) {
l_debug("Ignored: unsupported oper class");
return 0;
}
}
freq = scan_channel_to_freq(info->channel_num, band);
if (!freq) {
l_debug("Ignored: unsupported channel");
return 0;
}
if (out_band)
*out_band = band;
return freq;
}
static void device_neighbor_report_cb(struct netdev *netdev, int err,
const uint8_t *reports,
size_t reports_len, void *user_data)
{
struct device *device = user_data;
struct ie_tlv_iter iter;
int count_md = 0, count_no_md = 0;
struct scan_freq_set *freq_set_md, *freq_set_no_md;
uint32_t current_freq = 0;
struct handshake_state *hs = netdev_get_handshake(device->netdev);
/*
* Check if we're still attempting to roam -- if dbus Disconnect
* had been called in the meantime we just abort the attempt.
*/
if (!device->preparing_roam || err == -ENODEV)
return;
if (!reports || err) {
/* Have to do a full scan */
device_roam_scan(device, NULL);
return;
}
freq_set_md = scan_freq_set_new();
freq_set_no_md = scan_freq_set_new();
ie_tlv_iter_init(&iter, reports, reports_len);
/* First see if any of the reports contain the MD bit set */
while (ie_tlv_iter_next(&iter)) {
struct ie_neighbor_report_info info;
uint32_t freq;
enum scan_band band;
const uint8_t *cc = NULL;
if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_NEIGHBOR_REPORT)
continue;
if (ie_parse_neighbor_report(&iter, &info) < 0)
continue;
l_debug("Neighbor report received for %s: ch %i "
"(oper class %i), %s",
util_address_to_string(info.addr),
(int) info.channel_num, (int) info.oper_class,
info.md ? "MD set" : "MD not set");
if (device->connected_bss->cc_present)
cc = device->connected_bss->cc;
freq = device_freq_from_neighbor_report(cc, &info, &band);
if (!freq)
continue;
/* Skip if the band is not supported */
if (!(band & wiphy_get_supported_bands(device->wiphy)))
continue;
if (!memcmp(info.addr, device->connected_bss->addr, ETH_ALEN)) {
/*
* If this report is for the current AP, don't add
* it to any of the lists yet. We will need to scan
* its channel because it may still be the best ranked
* or the only visible AP.
*/
current_freq = freq;
continue;
}
/* Add the frequency to one of the lists */
if (info.md && hs->mde) {
scan_freq_set_add(freq_set_md, freq);
count_md += 1;
} else {
scan_freq_set_add(freq_set_no_md, freq);
count_no_md += 1;
}
}
if (!current_freq)
current_freq = device->connected_bss->frequency;
/*
* If there are neighbor reports with the MD bit set then the bit
* is probably valid so scan only the frequencies of the neighbors
* with that bit set, which will allow us to use Fast Transition.
* Some APs, such as those based on hostapd do not set the MD bit
* even if the neighbor is within the MD.
*
* In any case we only select the frequencies here and will check
* the IEs in the scan results as the authoritative information
* on whether we can use Fast Transition, and rank BSSes based on
* that.
*
* TODO: possibly save the neighbors from outside the MD and if
* none of the ones in the MD end up working, try a non-FT
* transition to those neighbors. We should be using a
* blacklisting mechanism (for both initial connection and
* transitions) so that cound_md would not count the
* BSSes already used and when it goes down to 0 we'd
* automatically fall back to the non-FT candidates and then to
* full scan.
*/
if (count_md) {
scan_freq_set_add(freq_set_md, current_freq);
device_roam_scan(device, freq_set_md);
} else if (count_no_md) {
scan_freq_set_add(freq_set_no_md, current_freq);
device_roam_scan(device, freq_set_no_md);
} else
device_roam_scan(device, NULL);
scan_freq_set_free(freq_set_md);
scan_freq_set_free(freq_set_no_md);
}
static void device_roam_trigger_cb(struct l_timeout *timeout, void *user_data)
{
struct device *device = user_data;
l_debug("%d", device->index);
l_timeout_remove(device->roam_trigger_timeout);
device->roam_trigger_timeout = NULL;
device->preparing_roam = true;
/*
* If current BSS supports Neighbor Reports, narrow the scan down
* to channels occupied by known neighbors in the ESS. This isn't
* 100% reliable as the neighbor lists are not required to be
* complete or current. It is likely still better than doing a
* full scan. 10.11.10.1: "A neighbor report may not be exhaustive
* either by choice, or due to the fact that there may be neighbor
* APs not known to the AP."
*/
if (device->connected_bss->cap_rm_neighbor_report &&
!device->roam_no_orig_ap)
if (netdev_neighbor_report_req(device->netdev,
device_neighbor_report_cb) == 0)
return;
/* Otherwise do a full scan for target BSS candidates */
device_roam_scan(device, NULL);
}
static void device_roam_timeout_rearm(struct device *device, int seconds)
{
struct timespec now, min_timeout;
clock_gettime(CLOCK_MONOTONIC, &now);
min_timeout = now;
min_timeout.tv_sec += seconds;
if (device->roam_min_time.tv_sec < min_timeout.tv_sec ||
(device->roam_min_time.tv_sec == min_timeout.tv_sec &&
device->roam_min_time.tv_nsec < min_timeout.tv_nsec))
device->roam_min_time = min_timeout;
seconds = device->roam_min_time.tv_sec - now.tv_sec +
(device->roam_min_time.tv_nsec > now.tv_nsec ? 1 : 0);
device->roam_trigger_timeout =
l_timeout_create(seconds, device_roam_trigger_cb, device, NULL);
}
#define WNM_REQUEST_MODE_PREFERRED_CANDIDATE_LIST (1 << 0)
#define WNM_REQUEST_MODE_TERMINATION_IMMINENT (1 << 3)
#define WNM_REQUEST_MODE_ESS_DISASSOCIATION_IMMINENT (1 << 4)
static void device_ap_roam_frame_event(struct netdev *netdev,
const struct mmpdu_header *hdr,
const void *body, size_t body_len,
@ -958,104 +512,8 @@ static void device_ap_roam_frame_event(struct netdev *netdev,
{
struct device *device = user_data;
struct station *station = device->station;
uint32_t pos = 0;
uint8_t req_mode;
uint16_t dtimer;
uint8_t valid_interval;
if (device->preparing_roam || station->state == STATION_STATE_ROAMING)
return;
if (body_len < 7)
goto format_error;
/*
* First two bytes are checked by the frame watch (WNM category and
* WNM action). The third is the dialog token which is not relevant
* because we did not send a BSS transition query -- so skip these
* first three bytes.
*/
pos += 3;
req_mode = l_get_u8(body + pos);
pos++;
/*
* TODO: Disassociation timer and validity interval are currently not
* used since the BSS transition request is being handled immediately.
*/
dtimer = l_get_le16(body + pos);
pos += 2;
valid_interval = l_get_u8(body + pos);
pos++;
l_debug("BSS transition received from AP: Disassociation Time: %u, "
"Validity interval: %u", dtimer, valid_interval);
/* check req_mode for optional values */
if (req_mode & WNM_REQUEST_MODE_TERMINATION_IMMINENT) {
if (pos + 12 > body_len)
goto format_error;
pos += 12;
}
if (req_mode & WNM_REQUEST_MODE_ESS_DISASSOCIATION_IMMINENT ) {
uint8_t url_len;
if (pos + 1 > body_len)
goto format_error;
url_len = l_get_u8(body + pos);
pos++;
if (pos + url_len > body_len)
goto format_error;
pos += url_len;
}
device->ap_directed_roaming = true;
device->preparing_roam = true;
l_timeout_remove(device->roam_trigger_timeout);
device->roam_trigger_timeout = NULL;
if (req_mode & WNM_REQUEST_MODE_PREFERRED_CANDIDATE_LIST)
device_neighbor_report_cb(device->netdev, 0, body + pos,
body_len - pos, device);
else
device_roam_scan(device, NULL);
return;
format_error:
l_debug("bad AP roam frame formatting");
}
static void device_lost_beacon(struct device *device)
{
struct station *station = device->station;
l_debug("%d", device->index);
if (station->state != STATION_STATE_ROAMING &&
station->state != STATION_STATE_CONNECTED)
return;
/*
* Tell the roam mechanism to not bother requesting Neighbor Reports,
* preauthenticating or performing other over-the-DS type of
* authentication to target AP, even while device->connected_bss is
* still non-NULL. The current connection is in a serious condition
* and we might wasting our time with those mechanisms.
*/
device->roam_no_orig_ap = true;
if (device->preparing_roam || station->state == STATION_STATE_ROAMING)
return;
device_roam_trigger_cb(NULL, device);
station_ap_directed_roam(station, hdr, body, body_len);
}
static void device_connect_cb(struct netdev *netdev, enum netdev_result result,
@ -1143,32 +601,17 @@ static void device_netdev_event(struct netdev *netdev, enum netdev_event event,
l_debug("Associating");
break;
case NETDEV_EVENT_LOST_BEACON:
device_lost_beacon(device);
station_lost_beacon(station);
break;
case NETDEV_EVENT_DISCONNECT_BY_AP:
case NETDEV_EVENT_DISCONNECT_BY_SME:
device_disconnect_event(device);
break;
case NETDEV_EVENT_RSSI_THRESHOLD_LOW:
if (device->signal_low)
break;
device->signal_low = true;
if (device->preparing_roam ||
station->state == STATION_STATE_ROAMING)
break;
/* Set a 5-second initial timeout */
device_roam_timeout_rearm(device, 5);
station_low_rssi(station);
break;
case NETDEV_EVENT_RSSI_THRESHOLD_HIGH:
l_timeout_remove(device->roam_trigger_timeout);
device->roam_trigger_timeout = NULL;
device->signal_low = false;
station_ok_rssi(station);
break;
case NETDEV_EVENT_RSSI_LEVEL_NOTIFY:
if (device->signal_agent)
@ -2185,8 +1628,6 @@ static void device_free(void *user)
dbus = dbus_get_bus();
l_dbus_unregister_object(dbus, device_get_path(device));
l_timeout_remove(device->roam_trigger_timeout);
scan_ifindex_remove(device->index);
netdev_frame_watch_remove(device->netdev, device->ap_roam_watch);

2
src/device.h
View File

@ -33,6 +33,8 @@ const char *device_get_path(struct device *device);
bool device_is_busy(struct device *device);
struct wiphy *device_get_wiphy(struct device *device);
void device_disassociated(struct device *device);
void device_transition_start(struct device *device, struct scan_bss *bss);
void device_set_scan_results(struct device *device, struct l_queue *bss_list,
bool add_to_autoconnect);
struct network *device_network_find(struct device *device, const char *ssid,

569
src/station.c
View File

@ -26,12 +26,15 @@
#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <linux/if_ether.h>
#include <ell/ell.h>
#include "src/util.h"
#include "src/iwd.h"
#include "src/common.h"
#include "src/device.h"
#include "src/watchlist.h"
#include "src/scan.h"
#include "src/netdev.h"
@ -543,6 +546,570 @@ bool station_remove_state_watch(struct station *station, uint32_t id)
return watchlist_remove(&station->state_watches, id);
}
void station_roam_state_clear(struct station *station)
{
l_timeout_remove(station->roam_trigger_timeout);
station->roam_trigger_timeout = NULL;
station->preparing_roam = false;
station->signal_low = false;
station->roam_min_time.tv_sec = 0;
if (station->roam_scan_id)
scan_cancel(netdev_get_ifindex(station->netdev),
station->roam_scan_id);
}
static void station_roam_timeout_rearm(struct station *station, int seconds);
void station_roamed(struct station *station)
{
/*
* New signal high/low notification should occur on the next
* beacon from new AP.
*/
station->signal_low = false;
station->roam_min_time.tv_sec = 0;
station->roam_no_orig_ap = false;
}
void station_roam_failed(struct station *station)
{
struct device *device = netdev_get_device(station->netdev);
/*
* If we're still connected to the old BSS, only clear preparing_roam
* and reattempt in 60 seconds if signal level is still low at that
* time. Otherwise (we'd already started negotiating with the
* transition target, preparing_roam is false, state is roaming) we
* are now disconnected.
*/
l_debug("%d", netdev_get_ifindex(station->netdev));
station->preparing_roam = false;
station->roam_no_orig_ap = false;
station->ap_directed_roaming = false;
if (station->state == STATION_STATE_ROAMING)
device_disassociated(device);
else if (station->signal_low)
station_roam_timeout_rearm(station, 60);
}
static void station_roam_scan_triggered(int err, void *user_data)
{
struct station *station = user_data;
if (err) {
station_roam_failed(station);
return;
}
/*
* Do not update the Scanning property as we won't be updating the
* list of networks.
*/
}
static bool station_roam_scan_notify(uint32_t wiphy_id, uint32_t ifindex,
int err, struct l_queue *bss_list,
void *userdata)
{
struct station *station = userdata;
struct device *device = netdev_get_device(station->netdev);
struct network *network = station->connected_network;
struct handshake_state *hs = netdev_get_handshake(station->netdev);
struct scan_bss *bss;
struct scan_bss *best_bss = NULL;
double best_bss_rank = 0.0;
static const double RANK_FT_FACTOR = 1.3;
uint16_t mdid;
enum security orig_security, security;
bool seen = false;
if (err) {
station_roam_failed(station);
return false;
}
/*
* Do not call station_set_scan_results because this may have been
* a partial scan. We could at most update the current networks' BSS
* list in its station->networks entry.
*/
orig_security = network_get_security(network);
if (hs->mde)
ie_parse_mobility_domain_from_data(hs->mde, hs->mde[1] + 2,
&mdid, NULL, NULL);
/*
* BSSes in the bss_list come already ranked with their initial
* association preference rank value. We only need to add preference
* for BSSes that are within the FT Mobility Domain so as to favor
* Fast Roaming, if it is supported.
*/
while ((bss = l_queue_pop_head(bss_list))) {
double rank;
struct ie_rsn_info info;
int r;
/* Skip the BSS we are connected to if doing an AP roam */
if (station->ap_directed_roaming && !memcmp(bss->addr,
station->connected_bss->addr, 6))
goto next;
/* Skip result if it is not part of the ESS */
if (bss->ssid_len != hs->ssid_len ||
memcmp(bss->ssid, hs->ssid, hs->ssid_len))
goto next;
memset(&info, 0, sizeof(info));
r = scan_bss_get_rsn_info(bss, &info);
if (r < 0) {
if (r != -ENOENT)
goto next;
security = security_determine(bss->capability, NULL);
} else
security = security_determine(bss->capability, &info);
if (security != orig_security)
goto next;
seen = true;
if (!wiphy_can_connect(station->wiphy, bss))
goto next;
rank = bss->rank;
if (hs->mde && bss->mde_present && l_get_le16(bss->mde) == mdid)
rank *= RANK_FT_FACTOR;
if (rank > best_bss_rank) {
if (best_bss)
scan_bss_free(best_bss);
best_bss = bss;
best_bss_rank = rank;
continue;
}
next:
scan_bss_free(bss);
}
l_queue_destroy(bss_list, NULL);
if (!seen)
goto fail_free_bss;
/* See if we have anywhere to roam to */
if (!best_bss || scan_bss_addr_eq(best_bss, station->connected_bss))
goto fail_free_bss;
bss = network_bss_find_by_addr(network, best_bss->addr);
if (bss) {
scan_bss_free(best_bss);
best_bss = bss;
} else {
network_bss_add(network, best_bss);
l_queue_push_tail(station->bss_list, best_bss);
}
device_transition_start(device, best_bss);
return true;
fail_free_bss:
if (best_bss)
scan_bss_free(best_bss);
station_roam_failed(station);
return true;
}
static void station_roam_scan_destroy(void *userdata)
{
struct station *station = userdata;
station->roam_scan_id = 0;
}
static void station_roam_scan(struct station *station,
struct scan_freq_set *freq_set)
{
struct scan_parameters params = { .freqs = freq_set, .flush = true };
if (station->connected_network)
/* Use direct probe request */
params.ssid = network_get_ssid(station->connected_network);
station->roam_scan_id =
scan_active_full(netdev_get_ifindex(station->netdev), &params,
station_roam_scan_triggered,
station_roam_scan_notify, station,
station_roam_scan_destroy);
if (!station->roam_scan_id)
station_roam_failed(station);
}
static uint32_t station_freq_from_neighbor_report(const uint8_t *country,
struct ie_neighbor_report_info *info, enum scan_band *out_band)
{
enum scan_band band;
uint32_t freq;
if (info->oper_class == 0) {
/*
* Some Cisco APs report all operating class values as 0
* in the Neighbor Report Responses. Work around this by
* using the most likely operating class for the channel
* number as the 2.4GHz and 5GHz bands happen to mostly
* use channels in two disjoint ranges.
*/
if (info->channel_num >= 1 && info->channel_num <= 14)
band = SCAN_BAND_2_4_GHZ;
else if (info->channel_num >= 36 && info->channel_num <= 169)
band = SCAN_BAND_5_GHZ;
else {
l_debug("Ignored: 0 oper class with an unusual "
"channel number");
return 0;
}
} else {
band = scan_oper_class_to_band(country, info->oper_class);
if (!band) {
l_debug("Ignored: unsupported oper class");
return 0;
}
}
freq = scan_channel_to_freq(info->channel_num, band);
if (!freq) {
l_debug("Ignored: unsupported channel");
return 0;
}
if (out_band)
*out_band = band;
return freq;
}
static void station_neighbor_report_cb(struct netdev *netdev, int err,
const uint8_t *reports,
size_t reports_len, void *user_data)
{
struct station *station = user_data;
struct ie_tlv_iter iter;
int count_md = 0, count_no_md = 0;
struct scan_freq_set *freq_set_md, *freq_set_no_md;
uint32_t current_freq = 0;
struct handshake_state *hs = netdev_get_handshake(station->netdev);
/*
* Check if we're still attempting to roam -- if dbus Disconnect
* had been called in the meantime we just abort the attempt.
*/
if (!station->preparing_roam || err == -ENODEV)
return;
if (!reports || err) {
/* Have to do a full scan */
station_roam_scan(station, NULL);
return;
}
freq_set_md = scan_freq_set_new();
freq_set_no_md = scan_freq_set_new();
ie_tlv_iter_init(&iter, reports, reports_len);
/* First see if any of the reports contain the MD bit set */
while (ie_tlv_iter_next(&iter)) {
struct ie_neighbor_report_info info;
uint32_t freq;
enum scan_band band;
const uint8_t *cc = NULL;
if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_NEIGHBOR_REPORT)
continue;
if (ie_parse_neighbor_report(&iter, &info) < 0)
continue;
l_debug("Neighbor report received for %s: ch %i "
"(oper class %i), %s",
util_address_to_string(info.addr),
(int) info.channel_num, (int) info.oper_class,
info.md ? "MD set" : "MD not set");
if (station->connected_bss->cc_present)
cc = station->connected_bss->cc;
freq = station_freq_from_neighbor_report(cc, &info, &band);
if (!freq)
continue;
/* Skip if the band is not supported */
if (!(band & wiphy_get_supported_bands(station->wiphy)))
continue;
if (!memcmp(info.addr,
station->connected_bss->addr, ETH_ALEN)) {
/*
* If this report is for the current AP, don't add
* it to any of the lists yet. We will need to scan
* its channel because it may still be the best ranked
* or the only visible AP.
*/
current_freq = freq;
continue;
}
/* Add the frequency to one of the lists */
if (info.md && hs->mde) {
scan_freq_set_add(freq_set_md, freq);
count_md += 1;
} else {
scan_freq_set_add(freq_set_no_md, freq);
count_no_md += 1;
}
}
if (!current_freq)
current_freq = station->connected_bss->frequency;
/*
* If there are neighbor reports with the MD bit set then the bit
* is probably valid so scan only the frequencies of the neighbors
* with that bit set, which will allow us to use Fast Transition.
* Some APs, such as those based on hostapd do not set the MD bit
* even if the neighbor is within the MD.
*
* In any case we only select the frequencies here and will check
* the IEs in the scan results as the authoritative information
* on whether we can use Fast Transition, and rank BSSes based on
* that.
*
* TODO: possibly save the neighbors from outside the MD and if
* none of the ones in the MD end up working, try a non-FT
* transition to those neighbors. We should be using a
* blacklisting mechanism (for both initial connection and
* transitions) so that cound_md would not count the
* BSSes already used and when it goes down to 0 we'd
* automatically fall back to the non-FT candidates and then to
* full scan.
*/
if (count_md) {
scan_freq_set_add(freq_set_md, current_freq);
station_roam_scan(station, freq_set_md);
} else if (count_no_md) {
scan_freq_set_add(freq_set_no_md, current_freq);
station_roam_scan(station, freq_set_no_md);
} else
station_roam_scan(station, NULL);
scan_freq_set_free(freq_set_md);
scan_freq_set_free(freq_set_no_md);
}
static void station_roam_trigger_cb(struct l_timeout *timeout, void *user_data)
{
struct station *station = user_data;
l_debug("%d", netdev_get_ifindex(station->netdev));
l_timeout_remove(station->roam_trigger_timeout);
station->roam_trigger_timeout = NULL;
station->preparing_roam = true;
/*
* If current BSS supports Neighbor Reports, narrow the scan down
* to channels occupied by known neighbors in the ESS. This isn't
* 100% reliable as the neighbor lists are not required to be
* complete or current. It is likely still better than doing a
* full scan. 10.11.10.1: "A neighbor report may not be exhaustive
* either by choice, or due to the fact that there may be neighbor
* APs not known to the AP."
*/
if (station->connected_bss->cap_rm_neighbor_report &&
!station->roam_no_orig_ap)
if (!netdev_neighbor_report_req(station->netdev,
station_neighbor_report_cb))
return;
/* Otherwise do a full scan for target BSS candidates */
station_roam_scan(station, NULL);
}
static void station_roam_timeout_rearm(struct station *station, int seconds)
{
struct timespec now, min_timeout;
clock_gettime(CLOCK_MONOTONIC, &now);
min_timeout = now;
min_timeout.tv_sec += seconds;
if (station->roam_min_time.tv_sec < min_timeout.tv_sec ||
(station->roam_min_time.tv_sec == min_timeout.tv_sec &&
station->roam_min_time.tv_nsec < min_timeout.tv_nsec))
station->roam_min_time = min_timeout;
seconds = station->roam_min_time.tv_sec - now.tv_sec +
(station->roam_min_time.tv_nsec > now.tv_nsec ? 1 : 0);
station->roam_trigger_timeout =
l_timeout_create(seconds, station_roam_trigger_cb,
station, NULL);
}
void station_lost_beacon(struct station *station)
{
l_debug("%d", netdev_get_ifindex(station->netdev));
if (station->state != STATION_STATE_ROAMING &&
station->state != STATION_STATE_CONNECTED)
return;
/*
* Tell the roam mechanism to not bother requesting Neighbor Reports,
* preauthenticating or performing other over-the-DS type of
* authentication to target AP, even while station->connected_bss is
* still non-NULL. The current connection is in a serious condition
* and we might wasting our time with those mechanisms.
*/
station->roam_no_orig_ap = true;
if (station->preparing_roam || station->state == STATION_STATE_ROAMING)
return;
station_roam_trigger_cb(NULL, station);
}
#define WNM_REQUEST_MODE_PREFERRED_CANDIDATE_LIST (1 << 0)
#define WNM_REQUEST_MODE_TERMINATION_IMMINENT (1 << 3)
#define WNM_REQUEST_MODE_ESS_DISASSOCIATION_IMMINENT (1 << 4)
void station_ap_directed_roam(struct station *station,
const struct mmpdu_header *hdr,
const void *body, size_t body_len)
{
uint32_t pos = 0;
uint8_t req_mode;
uint16_t dtimer;
uint8_t valid_interval;
if (station->preparing_roam || station->state == STATION_STATE_ROAMING)
return;
if (body_len < 7)
goto format_error;
/*
* First two bytes are checked by the frame watch (WNM category and
* WNM action). The third is the dialog token which is not relevant
* because we did not send a BSS transition query -- so skip these
* first three bytes.
*/
pos += 3;
req_mode = l_get_u8(body + pos);
pos++;
/*
* TODO: Disassociation timer and validity interval are currently not
* used since the BSS transition request is being handled immediately.
*/
dtimer = l_get_le16(body + pos);
pos += 2;
valid_interval = l_get_u8(body + pos);
pos++;
l_debug("BSS transition received from AP: Disassociation Time: %u, "
"Validity interval: %u", dtimer, valid_interval);
/* check req_mode for optional values */
if (req_mode & WNM_REQUEST_MODE_TERMINATION_IMMINENT) {
if (pos + 12 > body_len)
goto format_error;
pos += 12;
}
if (req_mode & WNM_REQUEST_MODE_ESS_DISASSOCIATION_IMMINENT ) {
uint8_t url_len;
if (pos + 1 > body_len)
goto format_error;
url_len = l_get_u8(body + pos);
pos++;
if (pos + url_len > body_len)
goto format_error;
pos += url_len;
}
station->ap_directed_roaming = true;
station->preparing_roam = true;
l_timeout_remove(station->roam_trigger_timeout);
station->roam_trigger_timeout = NULL;
if (req_mode & WNM_REQUEST_MODE_PREFERRED_CANDIDATE_LIST)
station_neighbor_report_cb(station->netdev, 0, body + pos,
body_len - pos,station);
else
station_roam_scan(station, NULL);
return;
format_error:
l_debug("bad AP roam frame formatting");
}
void station_low_rssi(struct station *station)
{
if (station->signal_low)
return;
station->signal_low = true;
if (station->preparing_roam ||
station->state == STATION_STATE_ROAMING)
return;
/* Set a 5-second initial timeout */
station_roam_timeout_rearm(station, 5);
}
void station_ok_rssi(struct station *station)
{
l_timeout_remove(station->roam_trigger_timeout);
station->roam_trigger_timeout = NULL;
station->signal_low = false;
}
struct station *station_find(uint32_t ifindex)
{
const struct l_queue_entry *entry;
@ -587,6 +1154,8 @@ void station_free(struct station *station)
if (!l_queue_remove(station_list, station))
return;
l_timeout_remove(station->roam_trigger_timeout);
l_queue_destroy(station->networks_sorted, NULL);
l_hashmap_destroy(station->networks, network_free);
l_queue_destroy(station->bss_list, bss_free);

20
src/station.h
View File

@ -50,10 +50,19 @@ struct station {
struct l_hashmap *networks;
struct l_queue *networks_sorted;
/* Roaming related members */
struct timespec roam_min_time;
struct l_timeout *roam_trigger_timeout;
uint32_t roam_scan_id;
struct wiphy *wiphy;
struct netdev *netdev;
bool seen_hidden_networks : 1;
bool preparing_roam : 1;
bool signal_low : 1;
bool roam_no_orig_ap : 1;
bool ap_directed_roaming : 1;
};
void station_autoconnect_next(struct station *station);
@ -83,6 +92,17 @@ uint32_t station_add_state_watch(struct station *station,
station_destroy_func_t destroy);
bool station_remove_state_watch(struct station *station, uint32_t id);
void station_roam_state_clear(struct station *station);
void station_roam_failed(struct station *station);
void station_roamed(struct station *station);
void station_lost_beacon(struct station *station);
void station_ap_directed_roam(struct station *station,
const struct mmpdu_header *hdr,
const void *body, size_t body_len);
void station_low_rssi(struct station *station);
void station_ok_rssi(struct station *station);
struct station *station_find(uint32_t ifindex);
struct station *station_create(struct wiphy *wiphy, struct netdev *netdev);
void station_free(struct station *station);