mac80211: parse radiotap header earlier
We can now move the radiotap header parsing into ieee80211_monitor_start_xmit(). This moves it out of the hotpath, and also helps the code since now the radiotap header will no longer be present in ieee80211_xmit() etc. which is easier to understand. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
John W. Linville
parent
a26eb27ab4
commit
73b9f03a81
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@ -349,8 +349,6 @@ struct ieee80211_bss_conf {
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* @IEEE80211_TX_INTFL_RETRANSMISSION: This frame is being retransmitted
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* after TX status because the destination was asleep, it must not
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* be modified again (no seqno assignment, crypto, etc.)
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* @IEEE80211_TX_INTFL_HAS_RADIOTAP: This frame was injected and still
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* has a radiotap header at skb->data.
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* @IEEE80211_TX_INTFL_NL80211_FRAME_TX: Frame was requested through nl80211
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* MLME command (internal to mac80211 to figure out whether to send TX
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* status to user space)
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@ -402,7 +400,7 @@ enum mac80211_tx_control_flags {
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IEEE80211_TX_CTL_POLL_RESPONSE = BIT(17),
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IEEE80211_TX_CTL_MORE_FRAMES = BIT(18),
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IEEE80211_TX_INTFL_RETRANSMISSION = BIT(19),
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IEEE80211_TX_INTFL_HAS_RADIOTAP = BIT(20),
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/* hole at 20, use later */
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IEEE80211_TX_INTFL_NL80211_FRAME_TX = BIT(21),
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IEEE80211_TX_CTL_LDPC = BIT(22),
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IEEE80211_TX_CTL_STBC = BIT(23) | BIT(24),
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@ -1035,103 +1035,6 @@ ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx)
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/* actual transmit path */
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/*
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* deal with packet injection down monitor interface
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* with Radiotap Header -- only called for monitor mode interface
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*/
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static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
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struct sk_buff *skb)
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{
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/*
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* this is the moment to interpret and discard the radiotap header that
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* must be at the start of the packet injected in Monitor mode
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*
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* Need to take some care with endian-ness since radiotap
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* args are little-endian
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*/
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struct ieee80211_radiotap_iterator iterator;
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struct ieee80211_radiotap_header *rthdr =
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(struct ieee80211_radiotap_header *) skb->data;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
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NULL);
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u16 txflags;
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info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
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IEEE80211_TX_CTL_DONTFRAG;
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/*
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* for every radiotap entry that is present
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* (ieee80211_radiotap_iterator_next returns -ENOENT when no more
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* entries present, or -EINVAL on error)
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*/
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while (!ret) {
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ret = ieee80211_radiotap_iterator_next(&iterator);
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if (ret)
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continue;
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/* see if this argument is something we can use */
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switch (iterator.this_arg_index) {
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/*
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* You must take care when dereferencing iterator.this_arg
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* for multibyte types... the pointer is not aligned. Use
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* get_unaligned((type *)iterator.this_arg) to dereference
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* iterator.this_arg for type "type" safely on all arches.
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*/
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case IEEE80211_RADIOTAP_FLAGS:
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
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/*
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* this indicates that the skb we have been
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* handed has the 32-bit FCS CRC at the end...
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* we should react to that by snipping it off
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* because it will be recomputed and added
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* on transmission
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*/
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if (skb->len < (iterator._max_length + FCS_LEN))
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return false;
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skb_trim(skb, skb->len - FCS_LEN);
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}
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
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info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT;
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
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info->flags &= ~IEEE80211_TX_CTL_DONTFRAG;
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break;
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case IEEE80211_RADIOTAP_TX_FLAGS:
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txflags = le16_to_cpu(get_unaligned((__le16*)
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iterator.this_arg));
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if (txflags & IEEE80211_RADIOTAP_F_TX_NOACK)
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info->flags |= IEEE80211_TX_CTL_NO_ACK;
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break;
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/*
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* Please update the file
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* Documentation/networking/mac80211-injection.txt
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* when parsing new fields here.
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*/
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default:
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break;
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}
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}
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if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
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return false;
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/*
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* remove the radiotap header
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* iterator->_max_length was sanity-checked against
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* skb->len by iterator init
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*/
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skb_pull(skb, iterator._max_length);
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return true;
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}
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static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx,
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struct sk_buff *skb,
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struct ieee80211_tx_info *info,
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@ -1205,19 +1108,6 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
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tx->sdata = sdata;
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tx->channel = local->hw.conf.channel;
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/* process and remove the injection radiotap header */
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if (unlikely(info->flags & IEEE80211_TX_INTFL_HAS_RADIOTAP)) {
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if (!__ieee80211_parse_tx_radiotap(tx, skb))
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return TX_DROP;
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/*
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* __ieee80211_parse_tx_radiotap has now removed
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* the radiotap header that was present and pre-filled
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* 'tx' with tx control information.
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*/
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info->flags &= ~IEEE80211_TX_INTFL_HAS_RADIOTAP;
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}
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/*
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* If this flag is set to true anywhere, and we get here,
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* we are doing the needed processing, so remove the flag
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@ -1559,6 +1449,89 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
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rcu_read_unlock();
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}
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static bool ieee80211_parse_tx_radiotap(struct sk_buff *skb)
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{
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struct ieee80211_radiotap_iterator iterator;
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struct ieee80211_radiotap_header *rthdr =
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(struct ieee80211_radiotap_header *) skb->data;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
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NULL);
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u16 txflags;
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info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
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IEEE80211_TX_CTL_DONTFRAG;
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/*
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* for every radiotap entry that is present
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* (ieee80211_radiotap_iterator_next returns -ENOENT when no more
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* entries present, or -EINVAL on error)
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*/
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while (!ret) {
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ret = ieee80211_radiotap_iterator_next(&iterator);
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if (ret)
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continue;
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/* see if this argument is something we can use */
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switch (iterator.this_arg_index) {
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/*
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* You must take care when dereferencing iterator.this_arg
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* for multibyte types... the pointer is not aligned. Use
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* get_unaligned((type *)iterator.this_arg) to dereference
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* iterator.this_arg for type "type" safely on all arches.
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*/
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case IEEE80211_RADIOTAP_FLAGS:
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
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/*
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* this indicates that the skb we have been
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* handed has the 32-bit FCS CRC at the end...
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* we should react to that by snipping it off
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* because it will be recomputed and added
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* on transmission
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*/
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if (skb->len < (iterator._max_length + FCS_LEN))
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return false;
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skb_trim(skb, skb->len - FCS_LEN);
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}
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
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info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT;
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if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
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info->flags &= ~IEEE80211_TX_CTL_DONTFRAG;
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break;
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case IEEE80211_RADIOTAP_TX_FLAGS:
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txflags = get_unaligned_le16(iterator.this_arg);
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if (txflags & IEEE80211_RADIOTAP_F_TX_NOACK)
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info->flags |= IEEE80211_TX_CTL_NO_ACK;
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break;
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/*
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* Please update the file
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* Documentation/networking/mac80211-injection.txt
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* when parsing new fields here.
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*/
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default:
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break;
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}
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}
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if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
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return false;
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/*
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* remove the radiotap header
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* iterator->_max_length was sanity-checked against
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* skb->len by iterator init
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*/
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skb_pull(skb, iterator._max_length);
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return true;
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}
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netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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@ -1646,8 +1619,11 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
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memset(info, 0, sizeof(*info));
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info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
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IEEE80211_TX_CTL_INJECTED |
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IEEE80211_TX_INTFL_HAS_RADIOTAP;
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IEEE80211_TX_CTL_INJECTED;
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/* process and remove the injection radiotap header */
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if (!ieee80211_parse_tx_radiotap(skb))
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goto fail;
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rcu_read_lock();
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@ -1674,7 +1650,6 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
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}
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}
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/* pass the radiotap header up to xmit */
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ieee80211_xmit(sdata, skb);
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rcu_read_unlock();
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