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 } 173