Add a function that will verify a received OCI element.
Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@xxxxxxxxxxxxxx>
---
src/common/ocv.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++
src/common/ocv.h | 3 ++
2 files changed, 77 insertions(+)
diff --git a/src/common/ocv.c b/src/common/ocv.c
index be8ef68ac..9dac121e4 100644
--- a/src/common/ocv.c
+++ b/src/common/ocv.c
@@ -92,3 +92,77 @@ 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 uint8_t *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) {
+ snprintf(ocv_errorstr, sizeof(ocv_errorstr),
+ "OCV failed: did not recieve mandatory OCI");
+ return -1;
+ } else if (oci_ie_len != 3) {
+ snprintf(ocv_errorstr, sizeof(ocv_errorstr),
+ "OCV failed: received OCI of unexpected length (%d)",
+ (int)oci_ie_len);
+ return -1;
+ }
+
+ 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) {
+ 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 (ci->frequency != oci.freq) {
+ 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;
+ }
+
+ /** Whe shouldn't transmit with a higher bandwidth than the STA supports */
+ if (tx_chanwidth > oci.chanwidth) {
+ 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 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) {
+ 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) {
+ 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;
+}
diff --git a/src/common/ocv.h b/src/common/ocv.h
index b88835345..56c1898db 100644
--- a/src/common/ocv.h
+++ b/src/common/ocv.h
@@ -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 uint8_t *oci_ie, size_t oci_ie_len,
+ struct wpa_channel_info *ci, int tx_chanwidth,
+ int tx_seg1_idx);
#endif /* OCV_H */
--
2.18.0
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