On Fri, Nov 01, 2013 at 10:38:48PM -0700, Rajesh Chauhan wrote:
> Add support for WLAN driver to report frequency range(s) to be avoided
> because of interference. If SoftAP/P2P-GO is operating on interfering
> frequency then user space should stop and restart them avoiding
> interfering frequency range(s). User space may decide to continue
> operation on interfering frequency, but in such case, there might be
> impact on performance.
Keep the subject to:
cfg80211: add support for frequency interference events
Also explain on the commit log how this only adds cellular type
for now, but later interference event sources can be added.
The rest of the feedback is cosmetic.
> Signed-off-by: Rajesh Chauhan <rajeshc@xxxxxxxxxxxxxxxx>
> ---
> include/net/cfg80211.h | 35 +++++++++++++++++++++
> include/uapi/linux/nl80211.h | 42 +++++++++++++++++++++++++
> net/wireless/nl80211.c | 73 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 150 insertions(+)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 419202c..ffeaf79 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -1933,6 +1933,28 @@ struct cfg80211_update_ft_ies_params {
> };
>
> /**
> + * struct cfg80211_avoid_frequency_range - frequency range(s) to avoid
> + *
> + * This structure provides frequency range(s) that should be avoided
> + * because of interference.
> + *
> + * @interference_source: enum nl80211_freq_interference_source_type
> + * is used to specify source of interference.
> + * @start_freq: start of frequency (KHz)
> + * @end_freq: end of frequency (KHz)
> + */
> +struct cfg80211_avoid_frequency_range {
> + enum nl80211_freq_interference_source_type interference_source;
> + unsigned int start_freq;
> + unsigned int end_freq;
> +};
> +
> +struct cfg80211_avoid_frequency_list {
> + unsigned int n_freq_ranges;
> + struct cfg80211_avoid_frequency_range *freq_range[0];
> +};
> +
> +/**
> * struct cfg80211_ops - backend description for wireless configuration
> *
> * This struct is registered by fullmac card drivers and/or wireless stacks
> @@ -4349,6 +4371,19 @@ void cfg80211_ft_event(struct net_device *netdev,
> struct cfg80211_ft_event_params *ft_event);
>
> /**
> + * cfg80211_avoid_frequency_event - notify userspace about frequency range(s)
> + * to avoid because of interference.
Johannes had noted before kerneldoc doesn't like multiline titles,
keep the title one line, and add the rest on another line, and then
later the attributes. Refer to the documentation for nl80211_rate_info
as a good example. Please replace WLAN driver for "wireless drivers"
to be consistent with other documentation.
> + * @netdev: network device
> + * @freq_list: frequency range(s) information
> + * @gfp: allocation flags
> + *
> + * WLAN driver calls this function to notify userspace about frequency
> + * range(s) that should be avoided because of interference.
> + */
> +void cfg80211_avoid_frequency_event(struct net_device *netdev,
> + struct cfg80211_avoid_frequency_list *freq_list, gfp_t gfp);
> +
> +/**
> * cfg80211_get_p2p_attr - find and copy a P2P attribute from IE buffer
> * @ies: the input IE buffer
> * @len: the input length
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index fde2c02..cf24eeb 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -686,6 +686,13 @@
> * other station that transmission must be blocked until the channel
> * switch is complete.
> *
> + * @NL80211_CMD_AVOID_FREQUENCIES_EVENT: Send range(s) of interfering
> + * frequencies that should be avoided, from the WLAN driver to the user
Same here.
> + * space. If SoftAP/P2P-GO is operating on interfering frequency then
> + * user space should stop and resart them avoiding interfering frequency
> + * range(s). User space may decide to continue operation on interfering
> + * frequency, but in such case, there might be impact on performance.
> + *
> * @NL80211_CMD_MAX: highest used command number
> * @__NL80211_CMD_AFTER_LAST: internal use
> */
> @@ -853,6 +860,8 @@ enum nl80211_commands {
>
> NL80211_CMD_CHANNEL_SWITCH,
>
> + NL80211_CMD_AVOID_FREQUENCIES_EVENT,
> +
> /* add new commands above here */
>
> /* used to define NL80211_CMD_MAX below */
> @@ -1496,6 +1505,8 @@ enum nl80211_commands {
> * @NL80211_ATTR_RXMGMT_FLAGS: flags for nl80211_send_mgmt(), u32.
> * As specified in the &enum nl80211_rxmgmt_flags.
> *
> + * @NL80211_ATTR_AVOID_FREQUENCIES: Avoid frequencies container information
> + *
> * @NL80211_ATTR_MAX: highest attribute number currently defined
> * @__NL80211_ATTR_AFTER_LAST: internal use
> */
> @@ -1806,6 +1817,8 @@ enum nl80211_attrs {
>
> NL80211_ATTR_RXMGMT_FLAGS,
>
> + NL80211_ATTR_AVOID_FREQUENCIES,
> +
> /* add attributes here, update the policy in nl80211.c */
>
> __NL80211_ATTR_AFTER_LAST,
> @@ -2255,6 +2268,35 @@ enum nl80211_frequency_attr {
> #define NL80211_FREQUENCY_ATTR_MAX_TX_POWER NL80211_FREQUENCY_ATTR_MAX_TX_POWER
>
> /**
> + * enum nl80211_freq_interference_source_type - interference source type
> + * @NL80211_FREQUENCY_INTERFERENCE_SOURCE_CELLULAR: interference source
> + * is cellular
> + */
> +enum nl80211_freq_interference_source_type {
> + NL80211_FREQUENCY_INTERFERENCE_SOURCE_CELLULAR
Add a comma to the end, that way a patch that adds a new
source type would not have to remove your line, only add
a new line.
> +};
> +
> +/**
> + * enum nl80211_avoid_frequency_attr - avoid frequency attributes
> + * @__NL80211_FREQUENCY_ATTR_INVALID: attribute number 0 is reserved
> + * @NL80211_AVOID_FREQUENCY_ATTR_INTERFERENCE_SOURCE_TYPE: interference source
Line over 80.
> + * @NL80211_AVOID_FREQUENCY_ATTR_START_FREQ: Start of frequency (KHz) range
> + * @NL80211_AVOID_FREQUENCY_ATTR_END_FREQ: End of frequency (KHz) range
> + * @__NL80211_FREQUENCY_ATTR_AFTER_LAST: internal use
> + */
> +enum nl80211_avoid_frequency_attr {
> + __NL80211_AVOID_FREQUENCY_ATTR_INVALID,
> + NL80211_AVOID_FREQUENCY_ATTR_INTERFERENCE_SOURCE_TYPE,
> + NL80211_AVOID_FREQUENCY_ATTR_START_FREQ,
> + NL80211_AVOID_FREQUENCY_ATTR_END_FREQ,
> +
> + /* keep last */
> + __NL80211_AVOID_FREQUENCY_ATTR_AFTER_LAST,
> + NL80211_AVOID_FREQUENCY_ATTR_MAX =
> + __NL80211_AVOID_FREQUENCY_ATTR_AFTER_LAST - 1
> +};
> +
> +/**
> * enum nl80211_bitrate_attr - bitrate attributes
> * @__NL80211_BITRATE_ATTR_INVALID: attribute number 0 is reserved
> * @NL80211_BITRATE_ATTR_RATE: Bitrate in units of 100 kbps
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index cbbef88..469116f 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -354,6 +354,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
> [NL80211_ATTR_CSA_IES] = { .type = NLA_NESTED },
> [NL80211_ATTR_CSA_C_OFF_BEACON] = { .type = NLA_U16 },
> [NL80211_ATTR_CSA_C_OFF_PRESP] = { .type = NLA_U16 },
> + [NL80211_ATTR_AVOID_FREQUENCIES] = { .type = NLA_NESTED },
> };
>
> /* policy for the key attributes */
> @@ -11234,6 +11235,78 @@ void cfg80211_ft_event(struct net_device *netdev,
> }
> EXPORT_SYMBOL(cfg80211_ft_event);
>
> +void cfg80211_avoid_frequency_event(struct net_device *netdev,
> + struct cfg80211_avoid_frequency_list *freq_list, gfp_t gfp)
> +{
> + struct wiphy *wiphy;
> + struct cfg80211_registered_device *rdev;
> + struct sk_buff *msg;
> + void *hdr;
> + struct nlattr *nl_ranges, *nl_range;
> + int err = -EINVAL;
> + unsigned int i;
> +
> + if (!netdev || !netdev->ieee80211_ptr ||
> + !netdev->ieee80211_ptr->wiphy || !freq_list)
> + return;
> +
> + wiphy = netdev->ieee80211_ptr->wiphy;
> + rdev = wiphy_to_dev(wiphy);
> +
> + if (!rdev)
> + return;
> +
> + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
> + if (!msg)
> + return;
> +
> + hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_AVOID_FREQUENCIES_EVENT);
> + if (!hdr) {
> + nlmsg_free(msg);
> + return;
> + }
> +
> + if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
> + nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex))
> + goto nla_put_failure;
> +
> + nl_ranges = nla_nest_start(msg, NL80211_ATTR_AVOID_FREQUENCIES);
> + if (!nl_ranges)
> + goto nla_put_failure;
> +
> + for (i = 0; i < freq_list->n_freq_ranges; i++) {
> + nl_range = nla_nest_start(msg, i);
> + if (!nl_range)
> + goto nla_put_failure;
> +
> + if (nla_put_u32(msg,
> + NL80211_AVOID_FREQUENCY_ATTR_INTERFERENCE_SOURCE_TYPE,
> + freq_list->freq_range[i]->interference_source) ||
> + nla_put_u32(msg,
> + NL80211_AVOID_FREQUENCY_ATTR_START_FREQ,
> + freq_list->freq_range[i]->start_freq) ||
> + nla_put_u32(msg,
> + NL80211_AVOID_FREQUENCY_ATTR_END_FREQ,
> + freq_list->freq_range[i]->end_freq))
> + goto nla_put_failure;
> + nla_nest_end(msg, nl_range);
> + }
> + nla_nest_end(msg, nl_ranges);
> +
> + err = genlmsg_end(msg, hdr);
> + if (err < 0)
> + goto nla_put_failure;
> +
> + genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
> + nl80211_mlme_mcgrp.id, gfp);
Just note: beacon hints use nl80211_regulatory_mcgrp.id, and
this uses nl80211_mlme_mcgrp.id, this is fine but just wanted
to show how now we have two different types of frequency
advisories and we're using two separate multicast groups.
If we want to scale this sort of information I stand that we should
be seriously considering in the long term a frequency broker but this
is fine for now, just supporting my original argument and hope folks
are aware and can see what I mean by now.
> + return;
> +
> +nla_put_failure:
> + genlmsg_cancel(msg, hdr);
> + nlmsg_free(msg);
> +}
> +EXPORT_SYMBOL(cfg80211_avoid_frequency_event);
How this is implmented is not shown here, I would prefer
then that you explain how drivers should use
cfg80211_avoid_frequency_event() as an example. I am particularly
interested in seeing how the driver sets the start and end frequency
range, for example I suppose that for firmare that supports
20 MHz channel advisories we'd do something like:
start_freq = MHZ_TO_KHZ(channel->start_freq) - MHZ_TO_KHZ(10);
start_freq = MHZ_TO_KHZ(channel->end_freq) + MHZ_TO_KHZ(10);
I suppose firmware can evolve to later be able to pick up
VHT80 advidsories and this would change depending on the fw
avdisory type, for example.
Luis
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