From: Andy Green <[email protected]>
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
Signed-off-by: Andy Green <[email protected]>
---
net/mac80211/ieee80211.c | 209 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 199 insertions(+), 10 deletions(-)
Index: wireless-dev/net/mac80211/ieee80211.c
===================================================================
--- wireless-dev.orig/net/mac80211/ieee80211.c
+++ wireless-dev/net/mac80211/ieee80211.c
@@ -1118,7 +1118,111 @@ 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_convert_radiotap_to_control_and_remove(
+ 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 *hw_mode=tx->local->hw.conf.mode;
+
+ /* this can fail some sanity checks, drop packet if it does so */
+
+ if (ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len) < 0)
+ return TXRX_DROP;
+
+ /* 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 (returns -ve on end or
+ * on error)
+ */
+
+ while (ieee80211_radiotap_iterator_next(&iterator) >= 0) {
+ int i, target_rate;
+
+ /* see if this argument is something we can use */
+
+ switch (iterator.this_arg_index) {
+
+ 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 < hw_mode->num_rates; i++) {
+ struct ieee80211_rate *r = &hw_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 = hw_mode->num_rates;
+
+ }
+ break;
+
+ case IEEE80211_RADIOTAP_ANTENNA:
+ /* radiotap uses 0 for 1st ant,
+ * mac80211 is 1 for 1st ant
+ * absence of IEEE80211_RADIOTAP_ANTENNA
+ * gives default/diversity
+ */
+ control->antenna_sel_tx = (*iterator.this_arg) + 1;
+ break;
+
+ case IEEE80211_RADIOTAP_DBM_TX_POWER:
+ control->power_level = *iterator.this_arg;
+ break;
+
+ default:
+ break;
+ }
+
+ }
+
+ /* remove the radiotap header
+ * rthdr->it_len was sanity-checked against skb->len by iterator init
+ */
+ skb_pull(skb, le16_to_cpu(rthdr->it_len));
+
+ 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 +1230,9 @@ __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 +1242,32 @@ __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_convert_radiotap_to_control_and_remove(
+ 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 +1284,6 @@ __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 +1291,7 @@ __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 +1404,7 @@ 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 +1414,26 @@ 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 +1672,54 @@ 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;
+
+ /*
+ * 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(struct ieee80211_tx_packet_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
+ */
+
+ skb_set_mac_header(skb, prthdr->it_len);
+ skb_set_network_header(skb, prthdr->it_len +
+ sizeof(struct ieee80211_hdr));
+ skb_set_transport_header(skb, prthdr->it_len +
+ sizeof(struct ieee80211_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;
--
> + /* for every radiotap entry that is present (returns -ve on end or
> + * on error)
> + */
> +
> + while (ieee80211_radiotap_iterator_next(&iterator) >= 0) {
"returns -ve"? Also, this does >= 0 while the docs stated that -1 is
returned. Maybe the docs should be updated and the code should be
changed to actually return 0 or a negative error code for
iterator_next()? I don't see any value in the return code when it's
non-negative, but when it's negative there could be some value in
determining -EINVAL (invalid header) vs. -ENOENT (when it's the last
one) for example.
> + /*
> + * 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
> + */
Interesting thing I just thought about here. For hardware-based sequence
numbers we'll be updating the sequence number before sending it, and for
software-based sequence numbers we wouldn't be.
However, for a userspace MLME we really need to update the sequence
number, so we'll either want to have a radiotap flag determining whether
the sequence number should be updated or not when transmitting a frame
or we just update them all the time, even for software-sequence numbers.
bcm43xx for example allows to turn off hardware sequence numbers on a
per-frame basis, so it'd be able to do both, but I'm not sure we can
rely on such functionality hence we'll want to just update sequence
numbers all the time...
johannes