drivers/net/wireless/ath/ath9k/common.c

Source file repositories/reference/linux-study-clean/drivers/net/wireless/ath/ath9k/common.c

File Facts

System
Linux kernel
Corpus path
drivers/net/wireless/ath/ath9k/common.c
Extension
.c
Size
11053 bytes
Lines
406
Domain
Driver Families
Bucket
drivers/net
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (rx_stats->rs_status & ATH9K_RXERR_CRC) {
			rxs->flag |= RX_FLAG_FAILED_FCS_CRC;
			mic_error = false;
		}

		if ((rx_stats->rs_status & ATH9K_RXERR_DECRYPT) ||
		    (!is_mc && (rx_stats->rs_status & ATH9K_RXERR_KEYMISS))) {
			*decrypt_error = true;
			mic_error = false;
		}


		/*
		 * Reject error frames with the exception of
		 * decryption and MIC failures. For monitor mode,
		 * we also ignore the CRC error.
		 */
		status_mask = ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
			      ATH9K_RXERR_KEYMISS;

		if (ah->is_monitoring && (rxfilter & FIF_FCSFAIL))
			status_mask |= ATH9K_RXERR_CRC;

		if (rx_stats->rs_status & ~status_mask)
			return false;
	}

	/*
	 * For unicast frames the MIC error bit can have false positives,
	 * so all MIC error reports need to be validated in software.
	 * False negatives are not common, so skip software verification
	 * if the hardware considers the MIC valid.
	 */
	if (strip_mic)
		rxs->flag |= RX_FLAG_MMIC_STRIPPED;
	else if (is_mc && mic_error)
		rxs->flag |= RX_FLAG_MMIC_ERROR;

	return true;
}
EXPORT_SYMBOL(ath9k_cmn_rx_accept);

void ath9k_cmn_rx_skb_postprocess(struct ath_common *common,
				  struct sk_buff *skb,
				  struct ath_rx_status *rx_stats,
				  struct ieee80211_rx_status *rxs,
				  bool decrypt_error)
{
	struct ath_hw *ah = common->ah;
	struct ieee80211_hdr *hdr;
	int hdrlen, padpos, padsize;
	u8 keyix;
	__le16 fc;

	/* see if any padding is done by the hw and remove it */
	hdr = (struct ieee80211_hdr *) skb->data;
	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
	fc = hdr->frame_control;
	padpos = ieee80211_hdrlen(fc);

	/* The MAC header is padded to have 32-bit boundary if the
	 * packet payload is non-zero. The general calculation for
	 * padsize would take into account odd header lengths:
	 * padsize = (4 - padpos % 4) % 4; However, since only
	 * even-length headers are used, padding can only be 0 or 2
	 * bytes and we can optimize this a bit. In addition, we must
	 * not try to remove padding from short control frames that do
	 * not have payload. */
	padsize = padpos & 3;
	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
		memmove(skb->data + padsize, skb->data, padpos);
		skb_pull(skb, padsize);
	}

	keyix = rx_stats->rs_keyix;

	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error &&
	    ieee80211_has_protected(fc)) {
		rxs->flag |= RX_FLAG_DECRYPTED;
	} else if (ieee80211_has_protected(fc)
		   && !decrypt_error && skb->len >= hdrlen + 4) {
		keyix = skb->data[hdrlen + 3] >> 6;

		if (test_bit(keyix, common->keymap))
			rxs->flag |= RX_FLAG_DECRYPTED;
	}
	if (ah->sw_mgmt_crypto_rx &&
	    (rxs->flag & RX_FLAG_DECRYPTED) &&
	    ieee80211_is_mgmt(fc))
		/* Use software decrypt for management frames. */

Annotation

Implementation Notes