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OCV: Add function to verify a received OCI element 

ocv_verify_tx_params() verifies that the receive OCI element includes
field values that are compatible with the local channel configuration.

Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
This commit is contained in:
Mathy Vanhoef 2018-08-06 15:46:29 -04:00 committed by Jouni Malinen
parent f53aeff415
commit 697652085f
2 changed files with 80 additions and 0 deletions
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77
src/common/ocv.c
View File

@ -93,3 +93,80 @@ int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *pos)
*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;
}

3
src/common/ocv.h
View File

@ -33,5 +33,8 @@ int ocv_derive_all_parameters(struct oci_info *oci);
int ocv_insert_oci(struct wpa_channel_info *ci, u8 **argpos);
int ocv_insert_oci_kde(struct wpa_channel_info *ci, u8 **argpos);
int ocv_insert_extended_oci(struct wpa_channel_info *ci, u8 *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);
#endif /* OCV_H */