Re: [PATCH 4/5] rrm: add radio resource management module

This module takes care of radio measurements which an AP can request. There are many types of requests, and for now only beacon requests are supported. IWD will filter certain types of beacon requests that are NOT supported: - AP channel reports. Only single channel requests will be supported - Autonomous measurements. Only direct requests will be supported. IWD will not accept requets to trigger reports under certain conditions (SNR/RSSI thresholds, etc.) - Timed measurements. Only immediate measurements will be performed. The accuracy for timed measurements cannot be reliably guaranteed due to kernel scheduling/queues. - Full reporting detail. The AP can request the STA return the full set of IEs in a beacon. IWD does not currently save all IEs, plus there is quite a bit of complexity involved as certain IEs get truncated, and there are other length limitations. There are other limitations not specific to beacon requests: - IWD will support single measurement requests per report. Multiple measurement request IEs can be included, but the reports will be sent out separately. - IWD will limit the number of requests it responds to in a given amount of time. As it stands now this is hard coded to 2 requests per second maximum. This will prevent DoS attacks. - IWD will not accept any measurement requests from APs it is not connected to, and will not accept any requests until connected. --- Makefile.am | 1 + src/rrm.c | 764 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 765 insertions(+) create mode 100644 src/rrm.c

+/* + * Basically the same as 802.11-2016 9.4.2.21.7 + * + * Note: Not packed as this is only for saving values for response + */ +struct rrm_beacon_req_info { + uint8_t oper_class; + uint8_t channel; /* The single channel provided in request */ + uint8_t bssid[6]; + char *ssid;

+}; + +struct rrm_request_info { + uint32_t ifindex; + uint8_t from[6]; + uint8_t dialog_token; /* dialog token in Radio Measurement Request */ + uint8_t mtoken; /* token in measurement request element */ + uint8_t mode; + uint8_t type; + + /* TODO: once more measurements are supported this can be a union */ + struct rrm_beacon_req_info *beacon; +};

+ +static uint64_t last_request_us; +static const uint8_t wildcard_bss[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

+ +static void rrm_build_measurement_report(struct rrm_request_info *info, + const void *report, size_t report_len, + uint8_t *to) +{ + *to++ = IE_TYPE_MEASUREMENT_REPORT; + *to++ = 3 + report_len; + *to++ = info->mtoken; + *to++ = 0; + *to++ = info->type; + + if (report) + memcpy(to, report, report_len); +} + +static void rrm_register_frame_cb(struct l_genl_msg *msg, void *user_data) +{ + if (l_genl_msg_get_error(msg) < 0) + l_error("Could not register frame watch type %04x: %i", + L_PTR_TO_UINT(user_data), l_genl_msg_get_error(msg)); +} + +static void rrm_register_frame(uint32_t ifindex) +{ + struct l_genl_msg *msg; + uint16_t frame_type = 0x00d0; + uint8_t prefix[] = { 0x05, 0x00 }; /* Radio Measurment Request */ + + msg = l_genl_msg_new_sized(NL80211_CMD_REGISTER_FRAME, 34); + + l_genl_msg_append_attr(msg, NL80211_ATTR_IFINDEX, 4, &ifindex); + l_genl_msg_append_attr(msg, NL80211_ATTR_FRAME_TYPE, 2, &frame_type); + l_genl_msg_append_attr(msg, NL80211_ATTR_FRAME_MATCH, + sizeof(prefix), prefix); + + l_genl_family_send(nl80211, msg, rrm_register_frame_cb, + L_UINT_TO_PTR(frame_type), NULL); +} + +static void rrm_netdev_watch(struct netdev *netdev, + enum netdev_watch_event event, void *user_data) +{ + switch (event) { + case NETDEV_WATCH_EVENT_NEW: + rrm_register_frame(netdev_get_ifindex(netdev));

+ return; + default: + break; + } +} +

+static bool rrm_handle_beacon_scan(struct rrm_request_info *info, + bool passive) +{ + struct netdev *netdev = netdev_find(info->ifindex); + struct scan_freq_set *freqs = scan_freq_set_new(); + struct scan_parameters params = { .freqs = freqs, .flush = true }; + enum scan_band band = scan_oper_class_to_band(NULL, + info->beacon->oper_class); + uint32_t freq; + uint32_t scan_id; + + freq = scan_channel_to_freq(info->beacon->channel, band); + scan_freq_set_add(freqs, freq); + + if (passive) + scan_id = scan_passive(netdev_get_wdev_id(netdev), freqs, + rrm_scan_triggered, + rrm_scan_results, info, + rrm_info_destroy); + else + scan_id = scan_active_full(netdev_get_wdev_id(netdev), &params, + rrm_scan_triggered, + rrm_scan_results, info, + rrm_info_destroy); + + scan_freq_set_free(freqs);

+ + return scan_id != 0; +} +