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authorJohannes Berg <johannes@sipsolutions.net>2007-09-26 17:53:18 +0200
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-10 16:54:18 -0700
commit58d4185e36913d4fc94afa4b4daccb3c9aa01957 (patch)
tree77d2e8e423652f5bbf2e29e8c0b3e0aeb7858b9f
parent[MAC80211]: remove ALG_NONE (diff)
downloadlinux-dev-58d4185e36913d4fc94afa4b4daccb3c9aa01957.tar.xz
linux-dev-58d4185e36913d4fc94afa4b4daccb3c9aa01957.zip
[MAC80211]: improve radiotap injection
This improves radiotap injection by removing the shortcut over TX handlers that led to BUGS when injecting frames without setting a rate and also resulted in various other quirks. Now, TX handlers are run but some information that was present in the radiotap header is used instead of automatic settings. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: Andy Green <andy@warmcat.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--Documentation/networking/mac80211-injection.txt32
-rw-r--r--net/mac80211/ieee80211_i.h1
-rw-r--r--net/mac80211/tx.c195
3 files changed, 131 insertions, 97 deletions
diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt
index 53ef7a06f49c..84906ef3ed6e 100644
--- a/Documentation/networking/mac80211-injection.txt
+++ b/Documentation/networking/mac80211-injection.txt
@@ -13,15 +13,35 @@ The radiotap format is discussed in
./Documentation/networking/radiotap-headers.txt.
Despite 13 radiotap argument types are currently defined, most only make sense
-to appear on received packets. Currently three kinds of argument are used by
-the injection code, although it knows to skip any other arguments that are
-present (facilitating replay of captured radiotap headers directly):
+to appear on received packets. The following information is parsed from the
+radiotap headers and used to control injection:
- - IEEE80211_RADIOTAP_RATE - u8 arg in 500kbps units (0x02 --> 1Mbps)
+ * IEEE80211_RADIOTAP_RATE
- - IEEE80211_RADIOTAP_ANTENNA - u8 arg, 0x00 = ant1, 0x01 = ant2
+ rate in 500kbps units, automatic if invalid or not present
- - IEEE80211_RADIOTAP_DBM_TX_POWER - u8 arg, dBm
+
+ * IEEE80211_RADIOTAP_ANTENNA
+
+ antenna to use, automatic if not present
+
+
+ * IEEE80211_RADIOTAP_DBM_TX_POWER
+
+ transmit power in dBm, automatic if not present
+
+
+ * IEEE80211_RADIOTAP_FLAGS
+
+ IEEE80211_RADIOTAP_F_FCS: FCS will be removed and recalculated
+ IEEE80211_RADIOTAP_F_WEP: frame will be encrypted if key available
+ IEEE80211_RADIOTAP_F_FRAG: frame will be fragmented if longer than the
+ current fragmentation threshold. Note that
+ this flag is only reliable when software
+ fragmentation is enabled)
+
+The injection code can also skip all other currently defined radiotap fields
+facilitating replay of captured radiotap headers directly.
Here is an example valid radiotap header defining these three parameters
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d24b0574c436..0fe077747082 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -122,6 +122,7 @@ typedef enum {
#define IEEE80211_TXRXD_RXIN_SCAN BIT(4)
/* frame is destined to interface currently processed (incl. multicast frames) */
#define IEEE80211_TXRXD_RXRA_MATCH BIT(5)
+#define IEEE80211_TXRXD_TX_INJECTED BIT(6)
struct ieee80211_txrx_data {
struct sk_buff *skb;
struct net_device *dev;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 47416b0645db..1a531543bccb 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -222,6 +222,9 @@ ieee80211_tx_h_check_assoc(struct ieee80211_txrx_data *tx)
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
u32 sta_flags;
+ if (unlikely(tx->flags & IEEE80211_TXRXD_TX_INJECTED))
+ return TXRX_CONTINUE;
+
if (unlikely(tx->local->sta_scanning != 0) &&
((tx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_MGMT ||
(tx->fc & IEEE80211_FCTL_STYPE) != IEEE80211_STYPE_PROBE_REQ))
@@ -566,22 +569,27 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
{
struct rate_control_extra extra;
- memset(&extra, 0, sizeof(extra));
- extra.mode = tx->u.tx.mode;
- extra.ethertype = tx->ethertype;
-
- tx->u.tx.rate = rate_control_get_rate(tx->local, tx->dev, tx->skb,
- &extra);
- if (unlikely(extra.probe != NULL)) {
- tx->u.tx.control->flags |= IEEE80211_TXCTL_RATE_CTRL_PROBE;
- tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
- tx->u.tx.control->alt_retry_rate = tx->u.tx.rate->val;
- tx->u.tx.rate = extra.probe;
- } else {
+ if (likely(!tx->u.tx.rate)) {
+ memset(&extra, 0, sizeof(extra));
+ extra.mode = tx->u.tx.mode;
+ extra.ethertype = tx->ethertype;
+
+ tx->u.tx.rate = rate_control_get_rate(tx->local, tx->dev,
+ tx->skb, &extra);
+ if (unlikely(extra.probe != NULL)) {
+ tx->u.tx.control->flags |=
+ IEEE80211_TXCTL_RATE_CTRL_PROBE;
+ tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
+ tx->u.tx.control->alt_retry_rate = tx->u.tx.rate->val;
+ tx->u.tx.rate = extra.probe;
+ } else
+ tx->u.tx.control->alt_retry_rate = -1;
+
+ if (!tx->u.tx.rate)
+ return TXRX_DROP;
+ } else
tx->u.tx.control->alt_retry_rate = -1;
- }
- if (!tx->u.tx.rate)
- return TXRX_DROP;
+
if (tx->u.tx.mode->mode == MODE_IEEE80211G &&
(tx->sdata->flags & IEEE80211_SDATA_USE_PROTECTION) &&
(tx->flags & IEEE80211_TXRXD_FRAGMENTED) && extra.nonerp) {
@@ -611,19 +619,24 @@ ieee80211_tx_h_misc(struct ieee80211_txrx_data *tx)
struct ieee80211_tx_control *control = tx->u.tx.control;
struct ieee80211_hw_mode *mode = tx->u.tx.mode;
- if (!is_multicast_ether_addr(hdr->addr1)) {
- if (tx->skb->len + FCS_LEN > tx->local->rts_threshold &&
- tx->local->rts_threshold < IEEE80211_MAX_RTS_THRESHOLD) {
- control->flags |= IEEE80211_TXCTL_USE_RTS_CTS;
- control->flags |= IEEE80211_TXCTL_LONG_RETRY_LIMIT;
- control->retry_limit =
- tx->local->long_retry_limit;
+ if (!control->retry_limit) {
+ if (!is_multicast_ether_addr(hdr->addr1)) {
+ if (tx->skb->len + FCS_LEN > tx->local->rts_threshold
+ && tx->local->rts_threshold <
+ IEEE80211_MAX_RTS_THRESHOLD) {
+ control->flags |=
+ IEEE80211_TXCTL_USE_RTS_CTS;
+ control->flags |=
+ IEEE80211_TXCTL_LONG_RETRY_LIMIT;
+ control->retry_limit =
+ tx->local->long_retry_limit;
+ } else {
+ control->retry_limit =
+ tx->local->short_retry_limit;
+ }
} else {
- control->retry_limit =
- tx->local->short_retry_limit;
+ control->retry_limit = 1;
}
- } else {
- control->retry_limit = 1;
}
if (tx->flags & IEEE80211_TXRXD_FRAGMENTED) {
@@ -785,9 +798,8 @@ ieee80211_tx_handler ieee80211_tx_handlers[] =
* with Radiotap Header -- only called for monitor mode interface
*/
static ieee80211_txrx_result
-__ieee80211_parse_tx_radiotap(
- struct ieee80211_txrx_data *tx,
- struct sk_buff *skb, struct ieee80211_tx_control *control)
+__ieee80211_parse_tx_radiotap(struct ieee80211_txrx_data *tx,
+ struct sk_buff *skb)
{
/*
* this is the moment to interpret and discard the radiotap header that
@@ -802,18 +814,11 @@ __ieee80211_parse_tx_radiotap(
(struct ieee80211_radiotap_header *) skb->data;
struct ieee80211_hw_mode *mode = tx->local->hw.conf.mode;
int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
+ struct ieee80211_tx_control *control = tx->u.tx.control;
- /*
- * default control situation for all injected packets
- * FIXME: this does not suit all usage cases, expand to allow control
- */
-
- control->retry_limit = 1; /* no retry */
- control->flags &= ~(IEEE80211_TXCTL_USE_RTS_CTS |
- IEEE80211_TXCTL_USE_CTS_PROTECT);
- control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT |
- IEEE80211_TXCTL_NO_ACK;
- control->antenna_sel_tx = 0; /* default to default antenna */
+ control->flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
+ tx->flags |= IEEE80211_TXRXD_TX_INJECTED;
+ tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
/*
* for every radiotap entry that is present
@@ -846,19 +851,10 @@ __ieee80211_parse_tx_radiotap(
for (i = 0; i < mode->num_rates; i++) {
struct ieee80211_rate *r = &mode->rates[i];
- if (r->rate > target_rate)
- continue;
-
- control->rate = r;
-
- if (r->flags & IEEE80211_RATE_PREAMBLE2)
- control->tx_rate = r->val2;
- else
- control->tx_rate = r->val;
-
- /* end on exact match */
- if (r->rate == target_rate)
- i = mode->num_rates;
+ if (r->rate == target_rate) {
+ tx->u.tx.rate = r;
+ break;
+ }
}
break;
@@ -888,8 +884,19 @@ __ieee80211_parse_tx_radiotap(
skb_trim(skb, skb->len - FCS_LEN);
}
+ if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
+ control->flags &=
+ ~IEEE80211_TXCTL_DO_NOT_ENCRYPT;
+ if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
+ tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
break;
+ /*
+ * Please update the file
+ * Documentation/networking/mac80211-injection.txt
+ * when parsing new fields here.
+ */
+
default:
break;
}
@@ -908,14 +915,17 @@ __ieee80211_parse_tx_radiotap(
return TXRX_CONTINUE;
}
-static ieee80211_txrx_result inline
+/*
+ * initialises @tx
+ */
+static ieee80211_txrx_result
__ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
struct sk_buff *skb,
struct net_device *dev,
struct ieee80211_tx_control *control)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
- struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct ieee80211_hdr *hdr;
struct ieee80211_sub_if_data *sdata;
ieee80211_txrx_result res = TXRX_CONTINUE;
@@ -926,33 +936,31 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
tx->dev = dev; /* use original interface */
tx->local = local;
tx->sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-
+ tx->u.tx.control = control;
/*
- * set defaults for things that can be set by
- * injected radiotap headers
+ * Set this flag (used below to indicate "automatic fragmentation"),
+ * it will be cleared/left by radiotap as desired.
*/
- control->power_level = local->hw.conf.power_level;
- control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
+ tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
/* process and remove the injection radiotap header */
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
if (unlikely(sdata->type == IEEE80211_IF_TYPE_MNTR)) {
- if (__ieee80211_parse_tx_radiotap(tx, skb, control) ==
- TXRX_DROP) {
+ if (__ieee80211_parse_tx_radiotap(tx, skb) == TXRX_DROP)
return TXRX_DROP;
- }
+
/*
- * we removed the radiotap header after this point,
- * we filled control with what we could use
- * set to the actual ieee header now
+ * __ieee80211_parse_tx_radiotap has now removed
+ * the radiotap header that was present and pre-filled
+ * 'tx' with tx control information.
*/
- hdr = (struct ieee80211_hdr *) skb->data;
- res = TXRX_QUEUED; /* indication it was monitor packet */
}
+ hdr = (struct ieee80211_hdr *) skb->data;
+
tx->sta = sta_info_get(local, hdr->addr1);
tx->fc = le16_to_cpu(hdr->frame_control);
- tx->u.tx.control = control;
+
if (is_multicast_ether_addr(hdr->addr1)) {
tx->flags &= ~IEEE80211_TXRXD_TXUNICAST;
control->flags |= IEEE80211_TXCTL_NO_ACK;
@@ -960,19 +968,23 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
tx->flags |= IEEE80211_TXRXD_TXUNICAST;
control->flags &= ~IEEE80211_TXCTL_NO_ACK;
}
- if (local->fragmentation_threshold < IEEE80211_MAX_FRAG_THRESHOLD &&
- (tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
- skb->len + FCS_LEN > local->fragmentation_threshold &&
- !local->ops->set_frag_threshold)
- tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
- else
- tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
+
+ if (tx->flags & IEEE80211_TXRXD_FRAGMENTED) {
+ if ((tx->flags & IEEE80211_TXRXD_TXUNICAST) &&
+ skb->len + FCS_LEN > local->fragmentation_threshold &&
+ !local->ops->set_frag_threshold)
+ tx->flags |= IEEE80211_TXRXD_FRAGMENTED;
+ else
+ tx->flags &= ~IEEE80211_TXRXD_FRAGMENTED;
+ }
+
if (!tx->sta)
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
else if (tx->sta->clear_dst_mask) {
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
tx->sta->clear_dst_mask = 0;
}
+
hdrlen = ieee80211_get_hdrlen(tx->fc);
if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
@@ -984,11 +996,14 @@ __ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
}
/* Device in tx->dev has a reference added; use dev_put(tx->dev) when
- * finished with it. */
-static int inline ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
- struct sk_buff *skb,
- struct net_device *mdev,
- struct ieee80211_tx_control *control)
+ * finished with it.
+ *
+ * NB: @tx is uninitialised when passed in here
+ */
+static int ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
+ struct sk_buff *skb,
+ struct net_device *mdev,
+ struct ieee80211_tx_control *control)
{
struct ieee80211_tx_packet_data *pkt_data;
struct net_device *dev;
@@ -1001,6 +1016,7 @@ static int inline ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
}
if (unlikely(!dev))
return -ENODEV;
+ /* initialises tx with control */
__ieee80211_tx_prepare(tx, skb, dev, control);
return 0;
}
@@ -1081,6 +1097,7 @@ static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
return 0;
}
+ /* initialises tx */
res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
if (res_prepare == TXRX_DROP) {
@@ -1097,15 +1114,11 @@ static int ieee80211_tx(struct net_device *dev, struct sk_buff *skb,
sta = tx.sta;
tx.u.tx.mode = local->hw.conf.mode;
- if (res_prepare == TXRX_QUEUED) { /* if it was an injected packet */
- res = TXRX_CONTINUE;
- } else {
- for (handler = local->tx_handlers; *handler != NULL;
- handler++) {
- res = (*handler)(&tx);
- if (res != TXRX_CONTINUE)
- break;
- }
+ for (handler = local->tx_handlers; *handler != NULL;
+ handler++) {
+ res = (*handler)(&tx);
+ if (res != TXRX_CONTINUE)
+ break;
}
skb = tx.skb; /* handlers are allowed to change skb */
@@ -1857,7 +1870,7 @@ ieee80211_get_buffered_bc(struct ieee80211_hw *hw, int if_id,
cpu_to_le16(IEEE80211_FCTL_MOREDATA);
}
- if (ieee80211_tx_prepare(&tx, skb, local->mdev, control) == 0)
+ if (!ieee80211_tx_prepare(&tx, skb, local->mdev, control))
break;
dev_kfree_skb_any(skb);
}