From 73b9f03a813d66484105c4ed648a1aa66fa267aa Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 7 Oct 2011 14:01:26 +0200 Subject: [PATCH] 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 Signed-off-by: John W. Linville --- include/net/mac80211.h | 4 +- net/mac80211/tx.c | 201 ++++++++++++++++++----------------------- 2 files changed, 89 insertions(+), 116 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 05f102197cfe..021317367d55 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -349,8 +349,6 @@ struct ieee80211_bss_conf { * @IEEE80211_TX_INTFL_RETRANSMISSION: This frame is being retransmitted * after TX status because the destination was asleep, it must not * be modified again (no seqno assignment, crypto, etc.) - * @IEEE80211_TX_INTFL_HAS_RADIOTAP: This frame was injected and still - * has a radiotap header at skb->data. * @IEEE80211_TX_INTFL_NL80211_FRAME_TX: Frame was requested through nl80211 * MLME command (internal to mac80211 to figure out whether to send TX * status to user space) @@ -402,7 +400,7 @@ enum mac80211_tx_control_flags { IEEE80211_TX_CTL_POLL_RESPONSE = BIT(17), IEEE80211_TX_CTL_MORE_FRAMES = BIT(18), IEEE80211_TX_INTFL_RETRANSMISSION = BIT(19), - IEEE80211_TX_INTFL_HAS_RADIOTAP = BIT(20), + /* hole at 20, use later */ IEEE80211_TX_INTFL_NL80211_FRAME_TX = BIT(21), IEEE80211_TX_CTL_LDPC = BIT(22), IEEE80211_TX_CTL_STBC = BIT(23) | BIT(24), diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 7f7d45cf77d1..3d2b6b2749f6 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1035,103 +1035,6 @@ ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx) /* actual transmit path */ -/* - * deal with packet injection down monitor interface - * with Radiotap Header -- only called for monitor mode interface - */ -static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx, - struct sk_buff *skb) -{ - /* - * this is the moment to interpret and discard the radiotap header that - * must be at the start of the packet injected in Monitor mode - * - * Need to take some care with endian-ness since radiotap - * args are little-endian - */ - - struct ieee80211_radiotap_iterator iterator; - struct ieee80211_radiotap_header *rthdr = - (struct ieee80211_radiotap_header *) skb->data; - struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); - int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len, - NULL); - u16 txflags; - - info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT | - IEEE80211_TX_CTL_DONTFRAG; - - /* - * for every radiotap entry that is present - * (ieee80211_radiotap_iterator_next returns -ENOENT when no more - * entries present, or -EINVAL on error) - */ - - while (!ret) { - ret = ieee80211_radiotap_iterator_next(&iterator); - - if (ret) - continue; - - /* see if this argument is something we can use */ - switch (iterator.this_arg_index) { - /* - * You must take care when dereferencing iterator.this_arg - * for multibyte types... the pointer is not aligned. Use - * get_unaligned((type *)iterator.this_arg) to dereference - * iterator.this_arg for type "type" safely on all arches. - */ - case IEEE80211_RADIOTAP_FLAGS: - if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) { - /* - * this indicates that the skb we have been - * handed has the 32-bit FCS CRC at the end... - * we should react to that by snipping it off - * because it will be recomputed and added - * on transmission - */ - if (skb->len < (iterator._max_length + FCS_LEN)) - return false; - - skb_trim(skb, skb->len - FCS_LEN); - } - if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP) - info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT; - if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG) - info->flags &= ~IEEE80211_TX_CTL_DONTFRAG; - break; - - case IEEE80211_RADIOTAP_TX_FLAGS: - txflags = le16_to_cpu(get_unaligned((__le16*) - iterator.this_arg)); - if (txflags & IEEE80211_RADIOTAP_F_TX_NOACK) - info->flags |= IEEE80211_TX_CTL_NO_ACK; - break; - - /* - * Please update the file - * Documentation/networking/mac80211-injection.txt - * when parsing new fields here. - */ - - default: - break; - } - } - - if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */ - return false; - - /* - * remove the radiotap header - * iterator->_max_length was sanity-checked against - * skb->len by iterator init - */ - skb_pull(skb, iterator._max_length); - - return true; -} - static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx, struct sk_buff *skb, struct ieee80211_tx_info *info, @@ -1205,19 +1108,6 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata, tx->sdata = sdata; tx->channel = local->hw.conf.channel; - /* process and remove the injection radiotap header */ - if (unlikely(info->flags & IEEE80211_TX_INTFL_HAS_RADIOTAP)) { - if (!__ieee80211_parse_tx_radiotap(tx, skb)) - return TX_DROP; - - /* - * __ieee80211_parse_tx_radiotap has now removed - * the radiotap header that was present and pre-filled - * 'tx' with tx control information. - */ - info->flags &= ~IEEE80211_TX_INTFL_HAS_RADIOTAP; - } - /* * If this flag is set to true anywhere, and we get here, * we are doing the needed processing, so remove the flag @@ -1559,6 +1449,89 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) rcu_read_unlock(); } +static bool ieee80211_parse_tx_radiotap(struct sk_buff *skb) +{ + struct ieee80211_radiotap_iterator iterator; + struct ieee80211_radiotap_header *rthdr = + (struct ieee80211_radiotap_header *) skb->data; + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len, + NULL); + u16 txflags; + + info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT | + IEEE80211_TX_CTL_DONTFRAG; + + /* + * for every radiotap entry that is present + * (ieee80211_radiotap_iterator_next returns -ENOENT when no more + * entries present, or -EINVAL on error) + */ + + while (!ret) { + ret = ieee80211_radiotap_iterator_next(&iterator); + + if (ret) + continue; + + /* see if this argument is something we can use */ + switch (iterator.this_arg_index) { + /* + * You must take care when dereferencing iterator.this_arg + * for multibyte types... the pointer is not aligned. Use + * get_unaligned((type *)iterator.this_arg) to dereference + * iterator.this_arg for type "type" safely on all arches. + */ + case IEEE80211_RADIOTAP_FLAGS: + if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) { + /* + * this indicates that the skb we have been + * handed has the 32-bit FCS CRC at the end... + * we should react to that by snipping it off + * because it will be recomputed and added + * on transmission + */ + if (skb->len < (iterator._max_length + FCS_LEN)) + return false; + + skb_trim(skb, skb->len - FCS_LEN); + } + if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP) + info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT; + if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG) + info->flags &= ~IEEE80211_TX_CTL_DONTFRAG; + break; + + case IEEE80211_RADIOTAP_TX_FLAGS: + txflags = get_unaligned_le16(iterator.this_arg); + if (txflags & IEEE80211_RADIOTAP_F_TX_NOACK) + info->flags |= IEEE80211_TX_CTL_NO_ACK; + break; + + /* + * Please update the file + * Documentation/networking/mac80211-injection.txt + * when parsing new fields here. + */ + + default: + break; + } + } + + if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */ + return false; + + /* + * remove the radiotap header + * iterator->_max_length was sanity-checked against + * skb->len by iterator init + */ + skb_pull(skb, iterator._max_length); + + return true; +} + netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb, struct net_device *dev) { @@ -1646,8 +1619,11 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb, memset(info, 0, sizeof(*info)); info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS | - IEEE80211_TX_CTL_INJECTED | - IEEE80211_TX_INTFL_HAS_RADIOTAP; + IEEE80211_TX_CTL_INJECTED; + + /* process and remove the injection radiotap header */ + if (!ieee80211_parse_tx_radiotap(skb)) + goto fail; rcu_read_lock(); @@ -1674,7 +1650,6 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb, } } - /* pass the radiotap header up to xmit */ ieee80211_xmit(sdata, skb); rcu_read_unlock(); -- 2.20.1