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ieee802154: Add support for user scanning requests
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The ieee802154 layer should be able to scan a set of channels in order
to look for beacons advertizing PANs. Supporting this involves adding
two user commands: triggering scans and aborting scans. The user should
also be notified when a new beacon is received and also upon scan
termination.

A scan request structure is created to list the requirements and to be
accessed asynchronously when changing channels or receiving beacons.

Mac layers may now implement the ->trigger_scan() and ->abort_scan()
hooks.

Co-developed-by: David Girault <david.girault@qorvo.com>
Signed-off-by: David Girault <david.girault@qorvo.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20230103165644.432209-2-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
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Miquel Raynal authored and Stefan Schmidt committed Jan 3, 2023
1 parent d8b879c commit ed3557c
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Showing 7 changed files with 377 additions and 0 deletions.
3 changes: 3 additions & 0 deletions include/linux/ieee802154.h
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,9 @@
#define IEEE802154_SHORT_ADDR_LEN 2
#define IEEE802154_PAN_ID_LEN 2

/* Duration in superframe order */
#define IEEE802154_MAX_SCAN_DURATION 14
#define IEEE802154_ACTIVE_SCAN_DURATION 15
#define IEEE802154_LIFS_PERIOD 40
#define IEEE802154_SIFS_PERIOD 12
#define IEEE802154_MAX_SIFS_FRAME_SIZE 18
Expand Down
25 changes: 25 additions & 0 deletions include/net/cfg802154.h
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@

struct wpan_phy;
struct wpan_phy_cca;
struct cfg802154_scan_request;

#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
struct ieee802154_llsec_device_key;
Expand Down Expand Up @@ -67,6 +68,10 @@ struct cfg802154_ops {
struct wpan_dev *wpan_dev, bool mode);
int (*set_ackreq_default)(struct wpan_phy *wpan_phy,
struct wpan_dev *wpan_dev, bool ackreq);
int (*trigger_scan)(struct wpan_phy *wpan_phy,
struct cfg802154_scan_request *request);
int (*abort_scan)(struct wpan_phy *wpan_phy,
struct wpan_dev *wpan_dev);
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
void (*get_llsec_table)(struct wpan_phy *wpan_phy,
struct wpan_dev *wpan_dev,
Expand Down Expand Up @@ -278,6 +283,26 @@ struct ieee802154_coord_desc {
bool gts_permit;
};

/**
* struct cfg802154_scan_request - Scan request
*
* @type: type of scan to be performed
* @page: page on which to perform the scan
* @channels: channels in te %page to be scanned
* @duration: time spent on each channel, calculated with:
* aBaseSuperframeDuration * (2 ^ duration + 1)
* @wpan_dev: the wpan device on which to perform the scan
* @wpan_phy: the wpan phy on which to perform the scan
*/
struct cfg802154_scan_request {
enum nl802154_scan_types type;
u8 page;
u32 channels;
u8 duration;
struct wpan_dev *wpan_dev;
struct wpan_phy *wpan_phy;
};

struct ieee802154_llsec_key_id {
u8 mode;
u8 id;
Expand Down
58 changes: 58 additions & 0 deletions include/net/nl802154.h
Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,9 @@ enum nl802154_commands {
NL802154_CMD_DEL_SEC_LEVEL,

NL802154_CMD_SCAN_EVENT,
NL802154_CMD_TRIGGER_SCAN,
NL802154_CMD_ABORT_SCAN,
NL802154_CMD_SCAN_DONE,

/* add new commands above here */

Expand Down Expand Up @@ -134,6 +137,13 @@ enum nl802154_attrs {
NL802154_ATTR_NETNS_FD,

NL802154_ATTR_COORDINATOR,
NL802154_ATTR_SCAN_TYPE,
NL802154_ATTR_SCAN_FLAGS,
NL802154_ATTR_SCAN_CHANNELS,
NL802154_ATTR_SCAN_PREAMBLE_CODES,
NL802154_ATTR_SCAN_MEAN_PRF,
NL802154_ATTR_SCAN_DURATION,
NL802154_ATTR_SCAN_DONE_REASON,

/* add attributes here, update the policy in nl802154.c */

Expand Down Expand Up @@ -259,6 +269,54 @@ enum nl802154_coord {
NL802154_COORD_MAX,
};

/**
* enum nl802154_scan_types - Scan types
*
* @__NL802154_SCAN_INVALID: scan type number 0 is reserved
* @NL802154_SCAN_ED: An ED scan allows a device to obtain a measure of the peak
* energy in each requested channel
* @NL802154_SCAN_ACTIVE: Locate any coordinator transmitting Beacon frames using
* a Beacon Request command
* @NL802154_SCAN_PASSIVE: Locate any coordinator transmitting Beacon frames
* @NL802154_SCAN_ORPHAN: Relocate coordinator following a loss of synchronisation
* @NL802154_SCAN_ENHANCED_ACTIVE: Same as Active using Enhanced Beacon Request
* command instead of Beacon Request command
* @NL802154_SCAN_RIT_PASSIVE: Passive scan for RIT Data Request command frames
* instead of Beacon frames
* @NL802154_SCAN_ATTR_MAX: Maximum SCAN attribute number
*/
enum nl802154_scan_types {
__NL802154_SCAN_INVALID,
NL802154_SCAN_ED,
NL802154_SCAN_ACTIVE,
NL802154_SCAN_PASSIVE,
NL802154_SCAN_ORPHAN,
NL802154_SCAN_ENHANCED_ACTIVE,
NL802154_SCAN_RIT_PASSIVE,

/* keep last */
NL802154_SCAN_ATTR_MAX,
};

/**
* enum nl802154_scan_done_reasons - End of scan reasons
*
* @__NL802154_SCAN_DONE_REASON_INVALID: scan done reason number 0 is reserved.
* @NL802154_SCAN_DONE_REASON_FINISHED: The scan just finished naturally after
* going through all the requested and possible (complex) channels.
* @NL802154_SCAN_DONE_REASON_ABORTED: The scan was aborted upon user request.
* a Beacon Request command
* @NL802154_SCAN_DONE_REASON_MAX: Maximum scan done reason attribute number.
*/
enum nl802154_scan_done_reasons {
__NL802154_SCAN_DONE_REASON_INVALID,
NL802154_SCAN_DONE_REASON_FINISHED,
NL802154_SCAN_DONE_REASON_ABORTED,

/* keep last */
NL802154_SCAN_DONE_REASON_MAX,
};

/**
* enum nl802154_cca_modes - cca modes
*
Expand Down
220 changes: 220 additions & 0 deletions net/ieee802154/nl802154.c
Original file line number Diff line number Diff line change
Expand Up @@ -221,6 +221,13 @@ static const struct nla_policy nl802154_policy[NL802154_ATTR_MAX+1] = {

[NL802154_ATTR_COORDINATOR] = { .type = NLA_NESTED },

[NL802154_ATTR_SCAN_TYPE] = { .type = NLA_U8 },
[NL802154_ATTR_SCAN_CHANNELS] = { .type = NLA_U32 },
[NL802154_ATTR_SCAN_PREAMBLE_CODES] = { .type = NLA_U64 },
[NL802154_ATTR_SCAN_MEAN_PRF] = { .type = NLA_U8 },
[NL802154_ATTR_SCAN_DURATION] = { .type = NLA_U8 },
[NL802154_ATTR_SCAN_DONE_REASON] = { .type = NLA_U8 },

#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },
[NL802154_ATTR_SEC_OUT_LEVEL] = { .type = NLA_U32, },
Expand Down Expand Up @@ -1384,6 +1391,203 @@ int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
}
EXPORT_SYMBOL_GPL(nl802154_scan_event);

static int nl802154_trigger_scan(struct sk_buff *skb, struct genl_info *info)
{
struct cfg802154_registered_device *rdev = info->user_ptr[0];
struct net_device *dev = info->user_ptr[1];
struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
struct wpan_phy *wpan_phy = &rdev->wpan_phy;
struct cfg802154_scan_request *request;
u8 type;
int err;

/* Monitors are not allowed to perform scans */
if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
return -EPERM;

request = kzalloc(sizeof(*request), GFP_KERNEL);
if (!request)
return -ENOMEM;

request->wpan_dev = wpan_dev;
request->wpan_phy = wpan_phy;

type = nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE]);
switch (type) {
case NL802154_SCAN_PASSIVE:
request->type = type;
break;
default:
pr_err("Unsupported scan type: %d\n", type);
err = -EINVAL;
goto free_request;
}

if (info->attrs[NL802154_ATTR_PAGE]) {
request->page = nla_get_u8(info->attrs[NL802154_ATTR_PAGE]);
if (request->page > IEEE802154_MAX_PAGE) {
pr_err("Invalid page %d > %d\n",
request->page, IEEE802154_MAX_PAGE);
err = -EINVAL;
goto free_request;
}
} else {
/* Use current page by default */
request->page = wpan_phy->current_page;
}

if (info->attrs[NL802154_ATTR_SCAN_CHANNELS]) {
request->channels = nla_get_u32(info->attrs[NL802154_ATTR_SCAN_CHANNELS]);
if (request->channels >= BIT(IEEE802154_MAX_CHANNEL + 1)) {
pr_err("Invalid channels bitfield %x ≥ %lx\n",
request->channels,
BIT(IEEE802154_MAX_CHANNEL + 1));
err = -EINVAL;
goto free_request;
}
} else {
/* Scan all supported channels by default */
request->channels = wpan_phy->supported.channels[request->page];
}

if (info->attrs[NL802154_ATTR_SCAN_PREAMBLE_CODES] ||
info->attrs[NL802154_ATTR_SCAN_MEAN_PRF]) {
pr_err("Preamble codes and mean PRF not supported yet\n");
err = -EINVAL;
goto free_request;
}

if (info->attrs[NL802154_ATTR_SCAN_DURATION]) {
request->duration = nla_get_u8(info->attrs[NL802154_ATTR_SCAN_DURATION]);
if (request->duration > IEEE802154_MAX_SCAN_DURATION) {
pr_err("Duration is out of range\n");
err = -EINVAL;
goto free_request;
}
} else {
/* Use maximum duration order by default */
request->duration = IEEE802154_MAX_SCAN_DURATION;
}

if (wpan_dev->netdev)
dev_hold(wpan_dev->netdev);

err = rdev_trigger_scan(rdev, request);
if (err) {
pr_err("Failure starting scanning (%d)\n", err);
goto free_device;
}

return 0;

free_device:
if (wpan_dev->netdev)
dev_put(wpan_dev->netdev);
free_request:
kfree(request);

return err;
}

static int nl802154_prep_scan_msg(struct sk_buff *msg,
struct cfg802154_registered_device *rdev,
struct wpan_dev *wpan_dev, u32 portid,
u32 seq, int flags, u8 cmd, u8 arg)
{
void *hdr;

hdr = nl802154hdr_put(msg, portid, seq, flags, cmd);
if (!hdr)
return -ENOBUFS;

if (nla_put_u32(msg, NL802154_ATTR_WPAN_PHY, rdev->wpan_phy_idx))
goto nla_put_failure;

if (wpan_dev->netdev &&
nla_put_u32(msg, NL802154_ATTR_IFINDEX, wpan_dev->netdev->ifindex))
goto nla_put_failure;

if (nla_put_u64_64bit(msg, NL802154_ATTR_WPAN_DEV,
wpan_dev_id(wpan_dev), NL802154_ATTR_PAD))
goto nla_put_failure;

if (cmd == NL802154_CMD_SCAN_DONE &&
nla_put_u8(msg, NL802154_ATTR_SCAN_DONE_REASON, arg))
goto nla_put_failure;

genlmsg_end(msg, hdr);

return 0;

nla_put_failure:
genlmsg_cancel(msg, hdr);

return -EMSGSIZE;
}

static int nl802154_send_scan_msg(struct cfg802154_registered_device *rdev,
struct wpan_dev *wpan_dev, u8 cmd, u8 arg)
{
struct sk_buff *msg;
int ret;

msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;

ret = nl802154_prep_scan_msg(msg, rdev, wpan_dev, 0, 0, 0, cmd, arg);
if (ret < 0) {
nlmsg_free(msg);
return ret;
}

return genlmsg_multicast_netns(&nl802154_fam,
wpan_phy_net(&rdev->wpan_phy), msg, 0,
NL802154_MCGRP_SCAN, GFP_KERNEL);
}

int nl802154_scan_started(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev)
{
struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(wpan_phy);
int err;

/* Ignore errors when there are no listeners */
err = nl802154_send_scan_msg(rdev, wpan_dev, NL802154_CMD_TRIGGER_SCAN, 0);
if (err == -ESRCH)
err = 0;

return err;
}
EXPORT_SYMBOL_GPL(nl802154_scan_started);

int nl802154_scan_done(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
enum nl802154_scan_done_reasons reason)
{
struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(wpan_phy);
int err;

/* Ignore errors when there are no listeners */
err = nl802154_send_scan_msg(rdev, wpan_dev, NL802154_CMD_SCAN_DONE, reason);
if (err == -ESRCH)
err = 0;

if (wpan_dev->netdev)
dev_put(wpan_dev->netdev);

return err;
}
EXPORT_SYMBOL_GPL(nl802154_scan_done);

static int nl802154_abort_scan(struct sk_buff *skb, struct genl_info *info)
{
struct cfg802154_registered_device *rdev = info->user_ptr[0];
struct net_device *dev = info->user_ptr[1];
struct wpan_dev *wpan_dev = dev->ieee802154_ptr;

/* Resources are released in the notification helper above */
return rdev_abort_scan(rdev, wpan_dev);
}

#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
static const struct nla_policy nl802154_dev_addr_policy[NL802154_DEV_ADDR_ATTR_MAX + 1] = {
[NL802154_DEV_ADDR_ATTR_PAN_ID] = { .type = NLA_U16 },
Expand Down Expand Up @@ -2474,6 +2678,22 @@ static const struct genl_ops nl802154_ops[] = {
.internal_flags = NL802154_FLAG_NEED_NETDEV |
NL802154_FLAG_NEED_RTNL,
},
{
.cmd = NL802154_CMD_TRIGGER_SCAN,
.doit = nl802154_trigger_scan,
.flags = GENL_ADMIN_PERM,
.internal_flags = NL802154_FLAG_NEED_NETDEV |
NL802154_FLAG_CHECK_NETDEV_UP |
NL802154_FLAG_NEED_RTNL,
},
{
.cmd = NL802154_CMD_ABORT_SCAN,
.doit = nl802154_abort_scan,
.flags = GENL_ADMIN_PERM,
.internal_flags = NL802154_FLAG_NEED_NETDEV |
NL802154_FLAG_CHECK_NETDEV_UP |
NL802154_FLAG_NEED_RTNL,
},
#ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
{
.cmd = NL802154_CMD_SET_SEC_PARAMS,
Expand Down
3 changes: 3 additions & 0 deletions net/ieee802154/nl802154.h
Original file line number Diff line number Diff line change
Expand Up @@ -6,5 +6,8 @@ int nl802154_init(void);
void nl802154_exit(void);
int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
struct ieee802154_coord_desc *desc);
int nl802154_scan_started(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev);
int nl802154_scan_done(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
enum nl802154_scan_done_reasons reason);

#endif /* __IEEE802154_NL802154_H */
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