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 */ 19char ocv_errorstr[256]; 20 21 22int 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 else if (op_class_map->bw == BW40) 49 oci->sec_channel = (((oci->channel - 1) / 4) % 2) ? -1 : 1; 50 51 return 0; 52} 53 54 55int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos) 56{ 57 u8 op_class, channel; 58 u8 *pos = *argpos; 59 60 if (ieee80211_chaninfo_to_channel(ci->frequency, ci->chanwidth, 61 ci->sec_channel, 62 &op_class, &channel) < 0) { 63 wpa_printf(MSG_WARNING, 64 "Cannot determine operating class and channel for OCI element"); 65 return -1; 66 } 67 68 *pos++ = op_class; 69 *pos++ = channel; 70 *pos++ = ci->seg1_idx; 71 72 *argpos = pos; 73 return 0; 74} 75 76 77int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos) 78{ 79 u8 *pos = *argpos; 80 81 *pos++ = WLAN_EID_VENDOR_SPECIFIC; 82 *pos++ = RSN_SELECTOR_LEN + 3; 83 RSN_SELECTOR_PUT(pos, RSN_KEY_DATA_OCI); 84 pos += RSN_SELECTOR_LEN; 85 86 *argpos = pos; 87 return ocv_insert_oci(ci, argpos); 88} 89 90 91int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos) 92{ 93 *pos++ = WLAN_EID_EXTENSION; 94 *pos++ = 1 + OCV_OCI_LEN; 95 *pos++ = WLAN_EID_EXT_OCV_OCI; 96 return ocv_insert_oci(ci, &pos); 97} 98 99 100enum oci_verify_result 101ocv_verify_tx_params(const u8 *oci_ie, size_t oci_ie_len, 102 struct wpa_channel_info *ci, int tx_chanwidth, 103 int tx_seg1_idx) 104{ 105 struct oci_info oci; 106 107 if (!oci_ie) { 108 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 109 "did not receive mandatory OCI"); 110 return OCI_NOT_FOUND; 111 } 112 113 if (oci_ie_len != 3) { 114 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 115 "received OCI of unexpected length (%d)", 116 (int) oci_ie_len); 117 return OCI_INVALID_LENGTH; 118 } 119 120 os_memset(&oci, 0, sizeof(oci)); 121 oci.op_class = oci_ie[0]; 122 oci.channel = oci_ie[1]; 123 oci.seg1_idx = oci_ie[2]; 124 if (ocv_derive_all_parameters(&oci) != 0) { 125 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 126 "unable to interpret received OCI"); 127 return OCI_PARSE_ERROR; 128 } 129 130 /* Primary frequency used to send frames to STA must match the STA's */ 131 if ((int) ci->frequency != oci.freq) { 132 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 133 "primary channel mismatch in received OCI (we use %d but receiver is using %d)", 134 ci->frequency, oci.freq); 135 return OCI_PRIMARY_FREQ_MISMATCH; 136 } 137 138 /* We shouldn't transmit with a higher bandwidth than the STA supports 139 */ 140 if (tx_chanwidth > oci.chanwidth) { 141 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 142 "channel bandwidth mismatch in received OCI (we use %d but receiver only supports %d)", 143 tx_chanwidth, oci.chanwidth); 144 return OCI_CHANNEL_WIDTH_MISMATCH; 145 } 146 147 /* 148 * Secondary channel only needs be checked for 40 MHz in the 2.4 GHz 149 * band. In the 5 GHz band it's verified through the primary frequency. 150 * Note that the field ci->sec_channel is only filled in when we use 151 * 40 MHz. 152 */ 153 if (tx_chanwidth == 40 && ci->frequency < 2500 && 154 ci->sec_channel != oci.sec_channel) { 155 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 156 "secondary channel mismatch in received OCI (we use %d but receiver is using %d)", 157 ci->sec_channel, oci.sec_channel); 158 return OCI_SECONDARY_FREQ_MISMATCH; 159 } 160 161 /* 162 * When using a 160 or 80+80 MHz channel to transmit, verify that we use 163 * the same segments as the receiver by comparing frequency segment 1. 164 */ 165 if ((ci->chanwidth == CHAN_WIDTH_160 || 166 ci->chanwidth == CHAN_WIDTH_80P80) && 167 tx_seg1_idx != oci.seg1_idx) { 168 os_snprintf(ocv_errorstr, sizeof(ocv_errorstr), 169 "frequency segment 1 mismatch in received OCI (we use %d but receiver is using %d)", 170 tx_seg1_idx, oci.seg1_idx); 171 return OCI_SEG_1_INDEX_MISMATCH; 172 } 173 174 return OCI_SUCCESS; 175} 176