Re: Broken fragmentation
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2008-06-19 09:57:01
On Thu, 2008-06-19 at 12:20 +0300, Tomas Winkler wrote:
Johannes Your patch bellow has broken the fragmentation. Can you please have a look at this.
/* Setup duration field for the first fragment of the frame. Duration * for remaining fragments will be updated when they are being sent * to low-level driver in ieee80211_tx(). */ dur = ieee80211_duration(tx, is_multicast_ether_addr(hdr->addr1), (tx->flags & IEEE80211_TX_FRAGMENTED) ? tx->extra_frag[0]->len : 0); -- NULL pointer
Oops, you're right, I missed the part where it accesses the fragments, the bulk of the function does txinfo updates which I didn't want to apply to all fragments. There is another bug too, this must come after encryption since encryption can add to the length of the frame. What do you think about the patch below? Untested so far because I have to go and wanted to get it out to you. johannes --- net/mac80211/tx.c | 66 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 35 insertions(+), 31 deletions(-)
--- everything.orig/net/mac80211/tx.c 2008-06-19 11:25:12.000000000 +0200
+++ everything/net/mac80211/tx.c 2008-06-19 11:53:08.000000000 +0200@@ -87,8 +87,8 @@ static inline void ieee80211_dump_frame( } #endif /* CONFIG_MAC80211_LOWTX_FRAME_DUMP */ -static u16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr, - int next_frag_len) +static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, int group_addr, + int next_frag_len) { int rate, mrate, erp, dur, i; struct ieee80211_rate *txrate;
@@ -140,7 +140,7 @@ static u16 ieee80211_duration(struct iee /* data/mgmt */ if (0 /* FIX: data/mgmt during CFP */) - return 32768; + return cpu_to_le16(32768); if (group_addr) /* Group address as the destination - no ACK */ return 0;
@@ -210,7 +210,7 @@ static u16 ieee80211_duration(struct iee tx->sdata->bss_conf.use_short_preamble); } - return dur; + return cpu_to_le16(dur); } static int inline is_ieee80211_device(struct net_device *dev,
@@ -544,7 +544,6 @@ ieee80211_tx_h_misc(struct ieee80211_tx_ { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data; u16 fc = le16_to_cpu(hdr->frame_control); - u16 dur; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb); struct ieee80211_supported_band *sband;
@@ -602,14 +601,6 @@ ieee80211_tx_h_misc(struct ieee80211_tx_ info->flags |= IEEE80211_TX_CTL_SHORT_PREAMBLE; } - /* Setup duration field for the first fragment of the frame. Duration - * for remaining fragments will be updated when they are being sent - * to low-level driver in ieee80211_tx(). */ - dur = ieee80211_duration(tx, is_multicast_ether_addr(hdr->addr1), - (tx->flags & IEEE80211_TX_FRAGMENTED) ? - tx->extra_frag[0]->len : 0); - hdr->duration_id = cpu_to_le16(dur); - if ((info->flags & IEEE80211_TX_CTL_USE_RTS_CTS) || (info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)) { struct ieee80211_rate *rate;
@@ -755,6 +746,36 @@ ieee80211_tx_h_encrypt(struct ieee80211_ } static ieee80211_tx_result +ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx) +{ + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data; + int next_len, i; + int group_addr = is_multicast_ether_addr(hdr->addr1); + + if (!(tx->flags & IEEE80211_TX_FRAGMENTED)) { + hdr->duration_id = ieee80211_duration(tx, group_addr, 0); + return TX_CONTINUE; + } + + hdr->duration_id = ieee80211_duration(tx, group_addr, + tx->extra_frag[0]->len); + + for (i = 0; i < tx->num_extra_frag; i++) { + if (i + 1 < tx->num_extra_frag) { + next_len = tx->extra_frag[i + 1]->len; + } else { + next_len = 0; + tx->rate_idx = tx->last_frag_rate_idx; + } + + hdr = (struct ieee80211_hdr *)tx->extra_frag[i]->data; + hdr->duration_id = ieee80211_duration(tx, 0, next_len); + } + + return TX_CONTINUE; +} + +static ieee80211_tx_result ieee80211_tx_h_stats(struct ieee80211_tx_data *tx) { int i;
@@ -788,6 +809,7 @@ static ieee80211_tx_handler ieee80211_tx ieee80211_tx_h_fragment, /* handlers after fragment must be aware of tx info fragmentation! */ ieee80211_tx_h_encrypt, + ieee80211_tx_h_calculate_duration, ieee80211_tx_h_stats, NULL };
@@ -1139,24 +1161,6 @@ static int ieee80211_tx(struct net_devic return 0; } - if (tx.extra_frag) { - for (i = 0; i < tx.num_extra_frag; i++) { - int next_len, dur; - struct ieee80211_hdr *hdr = - (struct ieee80211_hdr *) - tx.extra_frag[i]->data; - - if (i + 1 < tx.num_extra_frag) { - next_len = tx.extra_frag[i + 1]->len; - } else { - next_len = 0; - tx.rate_idx = tx.last_frag_rate_idx; - } - dur = ieee80211_duration(&tx, 0, next_len); - hdr->duration_id = cpu_to_le16(dur); - } - } - retry: ret = __ieee80211_tx(local, skb, &tx); if (ret) {