diff options
Diffstat (limited to 'src/common/ocv.c')
| -rw-r--r-- | src/common/ocv.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/src/common/ocv.c b/src/common/ocv.c new file mode 100644 index 0000000000000..06badfbfb4549 --- /dev/null +++ b/src/common/ocv.c @@ -0,0 +1,172 @@ +/* + * Operating Channel Validation (OCV) + * Copyright (c) 2018, Mathy Vanhoef + * + * This software may be distributed under the terms of the BSD license. + * See README for more details. + */ + +#include "utils/includes.h" +#include "utils/common.h" +#include "drivers/driver.h" +#include "common/ieee802_11_common.h" +#include "ocv.h" + +/** + * Caller of OCV functionality may use various debug output functions, so store + * the error here and let the caller use an appropriate debug output function. + */ +char ocv_errorstr[256]; + + +int ocv_derive_all_parameters(struct oci_info *oci) +{ + const struct oper_class_map *op_class_map; + + oci->freq = ieee80211_chan_to_freq(NULL, oci->op_class, oci->channel); + if (oci->freq < 0) { + wpa_printf(MSG_INFO, + "Error interpreting OCI: unrecognized opclass/channel pair (%d/%d)", + oci->op_class, oci->channel); + return -1; + } + + op_class_map = get_oper_class(NULL, oci->op_class); + if (!op_class_map) { + wpa_printf(MSG_INFO, + "Error interpreting OCI: Unrecognized opclass (%d)", + oci->op_class); + return -1; + } + + oci->chanwidth = oper_class_bw_to_int(op_class_map); + oci->sec_channel = 0; + if (op_class_map->bw == BW40PLUS) + oci->sec_channel = 1; + else if (op_class_map->bw == BW40MINUS) + oci->sec_channel = -1; + + return 0; +} + + +int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos) +{ + u8 op_class, channel; + u8 *pos = *argpos; + + if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth, + ci->sec_channel, + &op_class, &channel) < 0) { + wpa_printf(MSG_WARNING, + "Cannot determine operating class and channel for OCI element"); + return -1; + } + + *pos++ = op_class; + *pos++ = channel; + *pos++ = ci->seg1_idx; + + *argpos = pos; + return 0; +} + + +int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos) +{ + u8 *pos = *argpos; + + *pos++ = WLAN_EID_VENDOR_SPECIFIC; + *pos++ = RSN_SELECTOR_LEN + 3; + RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI); + pos += RSN_SELECTOR_LEN; + + *argpos = pos; + return ocv_insert_oci(ci, argpos); +} + + +int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos) +{ + *pos++ = WLAN_EID_EXTENSION; + *pos++ = 1 + OCV_OCI_LEN; + *pos++ = WLAN_EID_EXT_OCV_OCI; + return ocv_insert_oci(ci, &pos); +} + + +int ocv_verify_tx_params(const u8 *oci_ie, size_t oci_ie_len, + struct wpa_channel_info *ci, int tx_chanwidth, + int tx_seg1_idx) +{ + struct oci_info oci; + + if (!oci_ie) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: did not receive mandatory OCI"); + return -1; + } + + if (oci_ie_len != 3) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: received OCI of unexpected length (%d)", + (int) oci_ie_len); + return -1; + } + + os_memset(&oci, 0, sizeof(oci)); + oci.op_class = oci_ie[0]; + oci.channel = oci_ie[1]; + oci.seg1_idx = oci_ie[2]; + if (ocv_derive_all_parameters(&oci) != 0) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: unable to interpret received OCI"); + return -1; + } + + /* Primary frequency used to send frames to STA must match the STA's */ + if ((int) ci->frequency != oci.freq) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: primary channel mismatch in received OCI (we use %d but receiver is using %d)", + ci->frequency, oci.freq); + return -1; + } + + /* We shouldn't transmit with a higher bandwidth than the STA supports + */ + if (tx_chanwidth > oci.chanwidth) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: channel bandwidth mismatch in received OCI (we use %d but receiver only supports %d)", + tx_chanwidth, oci.chanwidth); + return -1; + } + + /* + * Secondary channel only needs be checked for 40 MHz in the 2.4 GHz + * band. In the 5 GHz band it's verified through the primary frequency. + * Note that the field ci->sec_channel is only filled in when we use + * 40 MHz. + */ + if (tx_chanwidth == 40 && ci->frequency < 2500 && + ci->sec_channel != oci.sec_channel) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: secondary channel mismatch in received OCI (we use %d but receiver is using %d)", + ci->sec_channel, oci.sec_channel); + return -1; + } + + /* + * When using a 160 or 80+80 MHz channel to transmit, verify that we use + * the same segments as the receiver by comparing frequency segment 1. + */ + if ((ci->chanwidth == CHAN_WIDTH_160 || + ci->chanwidth == CHAN_WIDTH_80P80) && + tx_seg1_idx != oci.seg1_idx) { + os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), + "OCV failed: frequency segment 1 mismatch in received OCI (we use %d but receiver is using %d)", + tx_seg1_idx, oci.seg1_idx); + return -1; + } + + return 0; +} |