Try #Lucky13
- Integrated a patch from Michael Wu with (Thanks again Michael)
- whitespace errors
- an endian error
- a strict endian typing problem
- Johannes Berg's suggested use of get_unaligned() to protect unaligned
defreferences of all multibyte radiotap stuff
Try #12 Comments from Michael Wu
- Revert enum retcode stuff
- Handle flags, checking if FCS marked as present and snipping it
- kill a blank line
Try #11
- Change parser loop code around to deal with enum retcodes
Try #10 Comments from Michael Wu
- __ieee80211_convert_radiotap_to_control_and_remove ->
__ieee80211_parse_tx_radiotap
- death to vertical justification
- -ve to negative
- struct ieee80211_hw_mode should be called "mode" by convention
Try #9
- Normalize multiline comment style
Try #6
- Accounted for various comments from Johannes Berg
- Radiotap parsing is moved to cfg80211 as requested in a separate patch
Try #5
- De-indent last few indented comments
Try #4
- All from Michael Wu's feedback: further style heresies removed
- took account of radiotap arg alignment requirement. n-byte arg must be
placed on n-byte boundary using padding where necessary
Try #3
- moved to Michael Wu's method of tracking if we came in on a
monitor interface by using ifindex
- removed older proposed monitor interface tracking method and flags
- style fixes
- removed duped #include that is present in Michael Wu's patch already
Try #2
- took Michael Wu's advice about better tools and basing on wireless-dev
- took Luis Rodriguez's advice about coding style makeover
- took Pavel Roskin's advice about little-endian radiotap
CC: John Linville <[email protected]>
CC: Johannes Berg <[email protected]>
CC: Jiri Benc <[email protected]>
Signed-off-by: Andy Green <[email protected]>
---
net/mac80211/ieee80211.c | 234 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 224 insertions(+), 10 deletions(-)
Index: wireless-dev/net/mac80211/ieee80211.c
===================================================================
--- wireless-dev.orig/net/mac80211/ieee80211.c
+++ wireless-dev/net/mac80211/ieee80211.c
@@ -24,6 +24,7 @@
#include <linux/compiler.h>
#include <linux/bitmap.h>
#include <net/cfg80211.h>
+#include <asm/unaligned.h>
#include "ieee80211_common.h"
#include "ieee80211_i.h"
@@ -1118,7 +1119,138 @@ ieee80211_tx_h_ps_buf(struct ieee80211_t
}
-static void inline
+/*
+ * deal with packet injection down monitor interface
+ * 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)
+{
+ /*
+ * 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_hw_mode *mode = tx->local->hw.conf.mode;
+ int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
+
+ /*
+ * 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->key_idx = -1; /* no encryption key */
+ 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 */
+
+ /*
+ * for every radiotap entry that is present
+ * (ieee80211_radiotap_iterator_next returns -ENOENT when no more
+ * entries present, or -EINVAL on error)
+ */
+
+ while (!ret) {
+ int i, target_rate;
+
+ 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_RATE:
+ /*
+ * radiotap rate u8 is in 500kbps units eg, 0x02=1Mbps
+ * ieee80211 rate int is in 100kbps units eg, 0x0a=1Mbps
+ */
+ target_rate = (*iterator.this_arg) * 5;
+ 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;
+ }
+ break;
+
+ case IEEE80211_RADIOTAP_ANTENNA:
+ /*
+ * radiotap uses 0 for 1st ant, mac80211 is 1 for
+ * 1st ant
+ */
+ control->antenna_sel_tx = (*iterator.this_arg) + 1;
+ break;
+
+ case IEEE80211_RADIOTAP_DBM_TX_POWER:
+ control->power_level = *iterator.this_arg;
+ break;
+
+ 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 TXRX_DROP;
+
+ skb_trim(skb, skb->len - FCS_LEN);
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
+ return TXRX_DROP;
+
+ /*
+ * remove the radiotap header
+ * iterator->max_length was sanity-checked against
+ * skb->len by iterator init
+ */
+ skb_pull(skb, iterator.max_length);
+
+ return TXRX_CONTINUE;
+}
+
+
+static ieee80211_txrx_result inline
__ieee80211_tx_prepare(struct ieee80211_txrx_data *tx,
struct sk_buff *skb,
struct net_device *dev,
@@ -1126,6 +1258,9 @@ __ieee80211_tx_prepare(struct ieee80211_
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct ieee80211_sub_if_data *sdata;
+ ieee80211_txrx_result res = TXRX_CONTINUE;
+
int hdrlen;
memset(tx, 0, sizeof(*tx));
@@ -1135,7 +1270,32 @@ __ieee80211_tx_prepare(struct ieee80211_
tx->sdata = IEEE80211_DEV_TO_SUB_IF(dev);
tx->sta = sta_info_get(local, hdr->addr1);
tx->fc = le16_to_cpu(hdr->frame_control);
+
+ /*
+ * set defaults for things that can be set by
+ * injected radiotap headers
+ */
control->power_level = local->hw.conf.power_level;
+ control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
+ if (local->sta_antenna_sel != STA_ANTENNA_SEL_AUTO && tx->sta)
+ control->antenna_sel_tx = tx->sta->antenna_sel_tx;
+
+ /* 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) {
+ 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
+ */
+ hdr = (struct ieee80211_hdr *) skb->data;
+ res = TXRX_QUEUED; /* indication it was monitor packet */
+ }
+
tx->u.tx.control = control;
tx->u.tx.unicast = !is_multicast_ether_addr(hdr->addr1);
if (is_multicast_ether_addr(hdr->addr1))
@@ -1152,9 +1312,6 @@ __ieee80211_tx_prepare(struct ieee80211_
control->flags |= IEEE80211_TXCTL_CLEAR_DST_MASK;
tx->sta->clear_dst_mask = 0;
}
- control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
- if (local->sta_antenna_sel != STA_ANTENNA_SEL_AUTO && tx->sta)
- control->antenna_sel_tx = tx->sta->antenna_sel_tx;
hdrlen = ieee80211_get_hdrlen(tx->fc);
if (skb->len > hdrlen + sizeof(rfc1042_header) + 2) {
u8 *pos = &skb->data[hdrlen + sizeof(rfc1042_header)];
@@ -1162,6 +1319,7 @@ __ieee80211_tx_prepare(struct ieee80211_
}
control->flags |= IEEE80211_TXCTL_FIRST_FRAGMENT;
+ return res;
}
static int inline is_ieee80211_device(struct net_device *dev,
@@ -1274,7 +1432,7 @@ static int ieee80211_tx(struct net_devic
struct sta_info *sta;
ieee80211_tx_handler *handler;
struct ieee80211_txrx_data tx;
- ieee80211_txrx_result res = TXRX_DROP;
+ ieee80211_txrx_result res = TXRX_DROP, res_prepare;
int ret, i;
WARN_ON(__ieee80211_queue_pending(local, control->queue));
@@ -1284,15 +1442,26 @@ static int ieee80211_tx(struct net_devic
return 0;
}
- __ieee80211_tx_prepare(&tx, skb, dev, control);
+ res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
+
+ if (res_prepare == TXRX_DROP) {
+ dev_kfree_skb(skb);
+ return 0;
+ }
+
sta = tx.sta;
tx.u.tx.mgmt_interface = mgmt;
tx.u.tx.mode = local->hw.conf.mode;
- for (handler = local->tx_handlers; *handler != NULL; handler++) {
- res = (*handler)(&tx);
- if (res != TXRX_CONTINUE)
- break;
+ 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;
+ }
}
skb = tx.skb; /* handlers are allowed to change skb */
@@ -1531,6 +1700,51 @@ static int ieee80211_subif_start_xmit(st
goto fail;
}
+ if (unlikely(sdata->type == IEEE80211_IF_TYPE_MNTR)) {
+ struct ieee80211_radiotap_header *prthdr =
+ (struct ieee80211_radiotap_header *)skb->data;
+ u16 len;
+
+ /*
+ * there must be a radiotap header at the
+ * start in this case
+ */
+ if (unlikely(prthdr->it_version)) {
+ /* only version 0 is supported */
+ ret = 0;
+ goto fail;
+ }
+
+ skb->dev = local->mdev;
+
+ pkt_data = (struct ieee80211_tx_packet_data *)skb->cb;
+ memset(pkt_data, 0, sizeof(*pkt_data));
+ pkt_data->ifindex = sdata->dev->ifindex;
+ pkt_data->mgmt_iface = 0;
+ pkt_data->do_not_encrypt = 1;
+
+ /* above needed because we set skb device to master */
+
+ /*
+ * fix up the pointers accounting for the radiotap
+ * header still being in there. We are being given
+ * a precooked IEEE80211 header so no need for
+ * normal processing
+ */
+ len = le16_to_cpu(get_unaligned(&prthdr->it_len));
+ skb_set_mac_header(skb, len);
+ skb_set_network_header(skb, len + sizeof(hdr));
+ skb_set_transport_header(skb, len + sizeof(hdr));
+
+ /*
+ * pass the radiotap header up to
+ * the next stage intact
+ */
+ dev_queue_xmit(skb);
+
+ return 0;
+ }
+
nh_pos = skb_network_header(skb) - skb->data;
h_pos = skb_transport_header(skb) - skb->data;
--
Nothing about this patch, I'm fine with it, but a comment for future use
cases of this where we'll need some changes.
> @@ -1284,15 +1442,26 @@ static int ieee80211_tx(struct net_devic
> return 0;
> }
>
> - __ieee80211_tx_prepare(&tx, skb, dev, control);
> + res_prepare = __ieee80211_tx_prepare(&tx, skb, dev, control);
> +
> + if (res_prepare == TXRX_DROP) {
> + dev_kfree_skb(skb);
> + return 0;
> + }
> +
> sta = tx.sta;
> tx.u.tx.mgmt_interface = mgmt;
> tx.u.tx.mode = local->hw.conf.mode;
>
> - for (handler = local->tx_handlers; *handler != NULL; handler++) {
> - res = (*handler)(&tx);
> - if (res != TXRX_CONTINUE)
> - break;
> + 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;
> + }
I think I mentioned it before; we'll have to split up TX handlers here
to get proper sequence numbering for devices that do it in software,
otherwise we won't be able to send packets with the right sequence
number on such devices.
johannes