contrib/wpa/src/common/ocv.c

   1 /*
   2  * Operating Channel Validation (OCV)
   3  * Copyright (c) 2018, Mathy Vanhoef
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "utils/includes.h"
  10 #include "utils/common.h"
  11 #include "drivers/driver.h"
  12 #include "common/ieee802_11_common.h"
  13 #include "ocv.h"
  14
  15 /**
  16  * Caller of OCV functionality may use various debug output functions, so store
  17  * the error here and let the caller use an appropriate debug output function.
  18  */
  19 char ocv_errorstr[256];
  20
  21
  22 int ocv_derive_all_parameters(struct oci_info *oci)
  23 {
  24         const struct oper_class_map *op_class_map;
  25
  26         oci->freq = ieee80211_chan_to_freq(NULL, oci->op_class, oci->channel);
  27         if (oci->freq < 0) {
  28                 wpa_printf(MSG_INFO,
  29                            "Error interpreting OCI: unrecognized opclass/channel pair (%d/%d)",
  30                            oci->op_class, oci->channel);
  31                 return -1;
  32         }
  33
  34         op_class_map = get_oper_class(NULL, oci->op_class);
  35         if (!op_class_map) {
  36                 wpa_printf(MSG_INFO,
  37                            "Error interpreting OCI: Unrecognized opclass (%d)",
  38                            oci->op_class);
  39                 return -1;
  40         }
  41
  42         oci->chanwidth = oper_class_bw_to_int(op_class_map);
  43         oci->sec_channel = 0;
  44         if (op_class_map->bw == BW40PLUS)
  45                 oci->sec_channel = 1;
  46         else if (op_class_map->bw == BW40MINUS)
  47                 oci->sec_channel = -1;
  48
  49         return 0;
  50 }
  51
  52
  53 int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos)
  54 {
  55         u8 op_class, channel;
  56         u8 *pos = *argpos;
  57
  58         if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth,
  59                                           ci->sec_channel,
  60                                           &op_class, &channel) < 0) {
  61                 wpa_printf(MSG_WARNING,
  62                            "Cannot determine operating class and channel for OCI element");
  63                 return -1;
  64         }
  65
  66         *pos++ = op_class;
  67         *pos++ = channel;
  68         *pos++ = ci->seg1_idx;
  69
  70         *argpos = pos;
  71         return 0;
  72 }
  73
  74
  75 int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos)
  76 {
  77         u8 *pos = *argpos;
  78
  79         *pos++ = WLAN_EID_VENDOR_SPECIFIC;
  80         *pos++ = RSN_SELECTOR_LEN + 3;
  81         RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI);
  82         pos += RSN_SELECTOR_LEN;
  83
  84         *argpos = pos;
  85         return ocv_insert_oci(ci, argpos);
  86 }
  87
  88
  89 int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos)
  90 {
  91         *pos++ = WLAN_EID_EXTENSION;
  92         *pos++ = 1 + OCV_OCI_LEN;
  93         *pos++ = WLAN_EID_EXT_OCV_OCI;
  94         return ocv_insert_oci(ci, &pos);
  95 }
  96
  97
  98 int ocv_verify_tx_params(const u8 *oci_ie, size_t oci_ie_len,
  99                          struct wpa_channel_info *ci, int tx_chanwidth,
 100                          int tx_seg1_idx)
 101 {
 102         struct oci_info oci;
 103
 104         if (!oci_ie) {
 105                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 106                             "OCV failed: did not receive mandatory OCI");
 107                 return -1;
 108         }
 109
 110         if (oci_ie_len != 3) {
 111                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 112                             "OCV failed: received OCI of unexpected length (%d)",
 113                             (int) oci_ie_len);
 114                 return -1;
 115         }
 116
 117         os_memset(&oci, 0, sizeof(oci));
 118         oci.op_class = oci_ie[0];
 119         oci.channel = oci_ie[1];
 120         oci.seg1_idx = oci_ie[2];
 121         if (ocv_derive_all_parameters(&oci) != 0) {
 122                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 123                             "OCV failed: unable to interpret received OCI");
 124                 return -1;
 125         }
 126
 127         /* Primary frequency used to send frames to STA must match the STA's */
 128         if ((int) ci->frequency != oci.freq) {
 129                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 130                             "OCV failed: primary channel mismatch in received OCI (we use %d but receiver is using %d)",
 131                             ci->frequency, oci.freq);
 132                 return -1;
 133         }
 134
 135         /* We shouldn't transmit with a higher bandwidth than the STA supports
 136          */
 137         if (tx_chanwidth > oci.chanwidth) {
 138                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 139                             "OCV failed: channel bandwidth mismatch in received OCI (we use %d but receiver only supports %d)",
 140                             tx_chanwidth, oci.chanwidth);
 141                 return -1;
 142         }
 143
 144         /*
 145          * Secondary channel only needs be checked for 40 MHz in the 2.4 GHz
 146          * band. In the 5 GHz band it's verified through the primary frequency.
 147          * Note that the field ci->sec_channel is only filled in when we use
 148          * 40 MHz.
 149          */
 150         if (tx_chanwidth == 40 && ci->frequency < 2500 &&
 151             ci->sec_channel != oci.sec_channel) {
 152                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 153                             "OCV failed: secondary channel mismatch in received OCI (we use %d but receiver is using %d)",
 154                             ci->sec_channel, oci.sec_channel);
 155                 return -1;
 156         }
 157
 158         /*
 159          * When using a 160 or 80+80 MHz channel to transmit, verify that we use
 160          * the same segments as the receiver by comparing frequency segment 1.
 161          */
 162         if ((ci->chanwidth == CHAN_WIDTH_160 ||
 163              ci->chanwidth == CHAN_WIDTH_80P80) &&
 164             tx_seg1_idx != oci.seg1_idx) {
 165                 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr),
 166                             "OCV failed: frequency segment 1 mismatch in received OCI (we use %d but receiver is using %d)",
 167                             tx_seg1_idx, oci.seg1_idx);
 168                 return -1;
 169         }
 170
 171         return 0;
 172 }