offchannel: introduce new offchannel module
This module provides a convenient wrapper around both CMD_[CANCEL_]_REMAIN_ON_CHANNEL APIs. Certain protocols require going offchannel to send frames, and/or wait for a response. The frame-xchg module somewhat does this but has some limitations. For example you cannot just go offchannel; an initial frame must be sent out to start the procedure. In addition frame-xchg does not work for broadcasts since it expects an ACK. This module is much simpler and only handles going offchannel for a duration. During this time frames may be sent or received. After the duration the caller will get a callback and any included error if there was one. Any offchannel request can be cancelled prior to the duration expriring if the offchannel work has finished early.
This commit is contained in:
James Prestwood
Denis Kenzior
parent
e6b4354530
commit
bc36aca98e
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@ -247,6 +247,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h src/iwd.h src/missing.h \
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src/ip-pool.h src/ip-pool.c \
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src/band.h src/band.c \
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src/sysfs.h src/sysfs.c \
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src/offchannel.h src/offchannel.c \
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$(eap_sources) \
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$(builtin_sources)
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@ -0,0 +1,325 @@
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/*
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*
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* Wireless daemon for Linux
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*
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* Copyright (C) 2021 Intel Corporation. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <errno.h>
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#include <ell/ell.h>
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#include "linux/nl80211.h"
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#include "src/offchannel.h"
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#include "src/wiphy.h"
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#include "src/nl80211util.h"
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#include "src/iwd.h"
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#include "src/module.h"
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struct offchannel_info {
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uint64_t wdev_id;
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uint32_t freq;
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uint32_t duration;
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uint32_t roc_cmd_id;
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uint64_t roc_cookie;
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offchannel_started_cb_t started;
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offchannel_destroy_cb_t destroy;
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void *user_data;
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int error;
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struct wiphy_radio_work_item work;
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bool needs_cancel : 1;
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};
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static struct l_genl_family *nl80211;
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static struct l_queue *offchannel_list;
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static bool match_wdev(const void *a, const void *user_data)
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{
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const struct offchannel_info *info = a;
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const uint64_t *wdev_id = user_data;
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return info->wdev_id == *wdev_id;
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}
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static void offchannel_cancel_roc(struct offchannel_info *info)
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{
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struct l_genl_msg *msg;
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msg = l_genl_msg_new(NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL);
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l_genl_msg_append_attr(msg, NL80211_ATTR_WDEV, 8, &info->wdev_id);
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l_genl_msg_append_attr(msg, NL80211_ATTR_COOKIE, 8, &info->roc_cookie);
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/* Nothing much can be done if this fails */
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if (!l_genl_family_send(nl80211, msg, NULL, NULL, NULL))
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l_genl_msg_unref(msg);
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}
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static void offchannel_roc_cb(struct l_genl_msg *msg, void *user_data)
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{
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struct offchannel_info *info = user_data;
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info->error = l_genl_msg_get_error(msg);
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info->roc_cmd_id = 0;
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if (info->error < 0) {
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l_debug("Error from CMD_REMAIN_ON_CHANNEL (%d)", info->error);
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goto work_done;
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}
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info->error = nl80211_parse_attrs(msg, NL80211_ATTR_COOKIE,
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&info->roc_cookie, NL80211_ATTR_UNSPEC);
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if (info->error < 0) {
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l_error("Could not parse ROC cookie");
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goto work_done;
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}
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/* This request was cancelled, and ROC needs to be cancelled */
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if (info->needs_cancel)
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offchannel_cancel_roc(info);
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return;
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work_done:
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wiphy_radio_work_done(wiphy_find_by_wdev(info->wdev_id), info->work.id);
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}
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static bool offchannel_work_ready(struct wiphy_radio_work_item *item)
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{
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struct l_genl_msg *msg;
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struct offchannel_info *info = l_container_of(item,
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struct offchannel_info, work);
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msg = l_genl_msg_new(NL80211_CMD_REMAIN_ON_CHANNEL);
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l_genl_msg_append_attr(msg, NL80211_ATTR_WDEV, 8, &info->wdev_id);
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l_genl_msg_append_attr(msg, NL80211_ATTR_WIPHY_FREQ, 4, &info->freq);
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l_genl_msg_append_attr(msg, NL80211_ATTR_DURATION, 4, &info->duration);
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info->roc_cmd_id = l_genl_family_send(nl80211, msg, offchannel_roc_cb,
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info, NULL);
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if (!info->roc_cmd_id) {
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info->error = -EIO;
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l_genl_msg_unref(msg);
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return true;
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}
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l_queue_push_head(offchannel_list, info);
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return false;
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}
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static void offchannel_work_destroy(struct wiphy_radio_work_item *item)
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{
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struct offchannel_info *info = l_container_of(item,
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struct offchannel_info, work);
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if (info->destroy)
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info->destroy(info->error, info->user_data);
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l_queue_remove(offchannel_list, info);
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l_free(info);
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}
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static const struct wiphy_radio_work_item_ops offchannel_work_ops = {
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.do_work = offchannel_work_ready,
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.destroy = offchannel_work_destroy,
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};
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uint32_t offchannel_start(uint64_t wdev_id, uint32_t freq, uint32_t duration,
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offchannel_started_cb_t started, void *user_data,
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offchannel_destroy_cb_t destroy)
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{
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struct offchannel_info *info = l_new(struct offchannel_info, 1);
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info->wdev_id = wdev_id;
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info->freq = freq;
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info->duration = duration;
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info->started = started;
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info->destroy = destroy;
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info->user_data = user_data;
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/*
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* Set error as cancelled in case this work gets cancelled prior to
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* the wiphy work starting.
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*/
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info->error = -ECANCELED;
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return wiphy_radio_work_insert(wiphy_find_by_wdev(wdev_id),
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&info->work, 1, &offchannel_work_ops);
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}
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void offchannel_cancel(uint64_t wdev_id, uint32_t id)
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{
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struct wiphy *wiphy = wiphy_find_by_wdev(wdev_id);
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struct offchannel_info *info;
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int ret;
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if (!wiphy)
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return;
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/*
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* Exit if work does not exist, if it hasn't started 'done' the work,
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* otherwise decide how the work needs to be canceled.
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*/
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ret = wiphy_radio_work_is_running(wiphy, id);
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if (ret < 0)
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return;
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else if (ret == false)
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goto work_done;
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info = l_queue_find(offchannel_list, match_wdev, &wdev_id);
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if (!info)
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return;
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if (info->roc_cmd_id) {
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/*
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* If the command hasn't left the genl queue it can be cancelled
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* without any further action. Otherwise command has been sent
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* to the kernel and we must wait until ROC starts and cancel at
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* that time.
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*/
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if (!l_genl_family_request_sent(nl80211, info->roc_cmd_id)) {
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l_genl_family_cancel(nl80211, info->roc_cmd_id);
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info->roc_cmd_id = 0;
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goto work_done;
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}
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/*
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* Call destroy now to maintain consistency with any other
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* path leading to radio_work_done(). But set needs_cancel so
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* the ROC command can be canceled
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*/
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if (info->destroy)
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info->destroy(info->error, info->user_data);
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info->destroy = NULL;
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info->started = NULL;
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info->user_data = NULL;
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info->needs_cancel = true;
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return;
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}
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/*
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* Something weird must have happened on the kernel side. This error
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* will already be handled in offchannel_roc_cb but warn here to inform
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* the user.
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*/
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if (L_WARN_ON(!info->roc_cookie))
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return;
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/*
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* At this point we know ROC has at least been queued (potentially not
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* started) and can be cancelled. The work will be completed once the
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* kernel sends the cancel ROC event.
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*/
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offchannel_cancel_roc(info);
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return;
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work_done:
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wiphy_radio_work_done(wiphy, id);
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}
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static void offchannel_mlme_notify(struct l_genl_msg *msg, void *user_data)
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{
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struct offchannel_info *info;
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uint64_t wdev_id;
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uint64_t cookie;
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uint8_t cmd;
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cmd = l_genl_msg_get_command(msg);
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if (cmd != NL80211_CMD_REMAIN_ON_CHANNEL &&
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cmd != NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL)
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return;
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if (nl80211_parse_attrs(msg, NL80211_ATTR_WDEV, &wdev_id,
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NL80211_ATTR_COOKIE, &cookie,
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NL80211_ATTR_UNSPEC) < 0)
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return;
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info = l_queue_find(offchannel_list, match_wdev, &wdev_id);
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if (!info)
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return;
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/* ROC must have been started elsewhere, not by IWD */
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if (info->roc_cookie != cookie)
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return;
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switch (cmd) {
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case NL80211_CMD_REMAIN_ON_CHANNEL:
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if (info->started)
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info->started(info->user_data);
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break;
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case NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL:
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info->error = 0;
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wiphy_radio_work_done(wiphy_find_by_wdev(info->wdev_id),
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info->work.id);
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break;
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default:
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return;
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}
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}
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static int offchannel_init(void)
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{
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struct l_genl *genl = iwd_get_genl();
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nl80211 = l_genl_family_new(genl, NL80211_GENL_NAME);
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if (!nl80211) {
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l_error("Failed to obtain nl80211");
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return -EIO;
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}
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if (!l_genl_family_register(nl80211, "mlme", offchannel_mlme_notify,
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NULL, NULL)) {
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l_error("Failed to register for MLME");
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l_genl_family_free(nl80211);
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nl80211 = NULL;
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return -EIO;
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}
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offchannel_list = l_queue_new();
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return 0;
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}
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static void offchannel_exit(void)
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{
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l_debug("");
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l_genl_family_free(nl80211);
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nl80211 = NULL;
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l_queue_destroy(offchannel_list, l_free);
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}
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IWD_MODULE(offchannel, offchannel_init, offchannel_exit);
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@ -0,0 +1,29 @@
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/*
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*
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* Wireless daemon for Linux
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*
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* Copyright (C) 2021 Intel Corporation. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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typedef void (*offchannel_started_cb_t)(void *user_data);
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typedef void (*offchannel_destroy_cb_t)(int error, void *user_data);
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uint32_t offchannel_start(uint64_t wdev_id, uint32_t freq, uint32_t duration,
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offchannel_started_cb_t started, void *user_data,
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offchannel_destroy_cb_t destroy);
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void offchannel_cancel(uint64_t wdev_id, uint32_t id);
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