Add support for sending AMSDU packet with the
user defined config through debugfs. This helps in
testing the Rx-AMSDU path without needing a special
driver/stack.
Note: Its purely for debug purposes.
Signed-off-by: T Krushna Chaitanya <[email protected]>
---
Tests and Observations
==============
1) Verified the Rx-AMSDU logic with mac80211 based chip
it works fine all msdu's are delivered.
2) Wireshark parses this frame fine.
3)sample cmd: echo "0,7,5,100,00:10:18:a9:50:6c"
> /sys/kernel/debug/ieee80211/phy0/netdev:wlan0/send_amsdu
Issues: Comments are welcome
===
1) Netgear/Broadcom AP's are dropping some AMSDU's in
the AMSDU deaggregation when seen on wired side.
2) with 8K seeing a DMA timeout and warning in ath9k driver.
(will send a separate mail)
3) dev_alloc_skb allocates as below(local PAGE_SIZE=4096)
AMSDU Size: SKB tailroom
2304+26 2368
3839+26 7936
7935+26 16128
---
include/linux/ieee80211.h | 22 ++++
include/net/mac80211.h | 8 +-
net/mac80211/debugfs_netdev.c | 257
+++++++++++++++++++++++++++++++++++++++++
net/mac80211/ieee80211_i.h | 1 -
net/mac80211/mlme.c | 2 +-
net/mac80211/tx.c | 4 +-
net/mac80211/wme.c | 5 +
7 files changed, 293 insertions(+), 6 deletions(-)
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index ccf9ee1..b91902b 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -172,6 +172,28 @@
#define IEEE80211_HT_CTL_LEN 4
+/*AMSDU Params*/
+#define LLC_SNAP_LEN 8
+#define AMSDU_SIZE_2K 2304
+#define AMSDU_SIZE_4K 3839
+#define AMSDU_SIZE_8K 7935
+#define AMSDU_SHDR_LEN 14
+#define AMSDU_RESERVE 0
+
+struct ieee80211_amsdu_sub_header {
+ u8 daddr[6];
+ u8 saddr[6];
+ __le16 len;
+} __packed;
+
+struct ieee80211_amsdu_llc_hdr {
+ u8 llc_dsap;
+ u8 llc_ssap;
+ u8 llc_ctrl;
+ u8 snap_oui[3];
+ u16 snap_type;
+} __packed;
+
struct ieee80211_hdr {
__le16 frame_control;
__le16 duration_id;
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 23daed3..3bf5aef 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -470,6 +470,7 @@ enum mac80211_tx_control_flags {
IEEE80211_TX_STATUS_EOSP = BIT(28),
IEEE80211_TX_CTL_USE_MINRATE = BIT(29),
IEEE80211_TX_CTL_DONTFRAG = BIT(30),
+ IEEE80211_TX_CTL_AMSDU = BIT(31),
};
#define IEEE80211_TX_CTL_STBC_SHIFT 23
@@ -485,7 +486,8 @@ enum mac80211_tx_control_flags {
IEEE80211_TX_STAT_AMPDU | IEEE80211_TX_STAT_AMPDU_NO_BACK | \
IEEE80211_TX_CTL_RATE_CTRL_PROBE | IEEE80211_TX_CTL_NO_PS_BUFFER |
\
IEEE80211_TX_CTL_MORE_FRAMES | IEEE80211_TX_CTL_LDPC | \
- IEEE80211_TX_CTL_STBC | IEEE80211_TX_STATUS_EOSP)
+ IEEE80211_TX_CTL_STBC | IEEE80211_TX_STATUS_EOSP| \
+ IEEE80211_TX_CTL_AMSDU)
/**
* enum mac80211_rate_control_flags - per-rate flags set by the
@@ -1402,6 +1404,10 @@ enum ieee80211_hw_flags {
IEEE80211_HW_SCAN_WHILE_IDLE = 1<<24,
IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF = 1<<25,
IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL = 1<<26,
+ /* Some Drivers may not support 4K frame transmission
+ * in that case we need 2 bits, else 1 bit is enough*/
+ IEEE80211_HW_TX_4K_AMSDU = 1<<27,
+ IEEE80211_HW_TX_8K_AMSDU = 1<<28
};
/**
diff --git a/net/mac80211/debugfs_netdev.c
b/net/mac80211/debugfs_netdev.c
index cbde5cc..3041717 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -11,6 +11,7 @@
#include <linux/device.h>
#include <linux/if.h>
#include <linux/if_ether.h>
+#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
@@ -336,6 +337,261 @@ static ssize_t ieee80211_if_parse_tkip_mic_test(
__IEEE80211_IF_FILE_W(tkip_mic_test);
+static ssize_t ieee80211_if_fmt_send_amsdu(
+ const struct ieee80211_sub_if_data *sdata,
+ char *buf,
+ int buflen)
+{
+ return -EOPNOTSUPP;
+}
+static ssize_t ieee80211_if_parse_send_amsdu(
+ struct ieee80211_sub_if_data *sdata,
+ const char *buf,
+ int buflen)
+{
+ struct ieee80211_local *local = sdata->local;
+ struct sta_info *sta = NULL;
+ struct sk_buff *skb = NULL;
+ struct sk_buff *skb_amsdu = NULL;
+ struct ieee80211_hdr *hdr = NULL;
+ struct ieee80211_amsdu_sub_header *amsdu_shdr = NULL;
+ struct ieee80211_amsdu_llc_hdr amsdu_llc = { /* From mwifiex*/
+ 0xaa, /* LLC DSAP */
+ 0xaa, /* LLC SSAP */
+ 0x03, /* LLC CTRL */
+ {0x00, 0x00, 0x00}, /* SNAP OUI */
+ 0x9999 /* SNAP type */
+ };
+ __le16 fc, pad;
+
+ /*==== User Inputs===*/
+ u8 addr[ETH_ALEN] = {0x0};
+ u8 daddr[ETH_ALEN], saddr[ETH_ALEN], bssid[ETH_ALEN];
+ u32 tid;
+ u32 total_msdu, num_msdu;
+ u32 msdu_size, payload_size;
+ u32 amsdu_size = 0;
+
+ char *buffer;
+ /* Defaults: amsdu_size,tid,no of msdu's, size of msdu, DAddr*/
+ char *buffer_array[5] = {"0", "0", "3", "300", "ff:ff:ff:ff:ff:ff"};
+ int j = 0;
+
+ /* Sanity checks for the buffer Rx*/
+ if (buflen == 0 || !buf)
+ return -EINVAL;
+
+ /*We have already copied data from user space*/
+ buffer = kstrdup(buf, GFP_KERNEL);
+ /* Its reentrant safe.*/
+ while ((buffer_array[j] = strsep(&buffer, ",")) != NULL) {
+ /*Skip the MAC address part, we will handle it below*/
+ j++;
+ }
+ /* Conver to respective data types*/
+ kstrtouint(buffer_array[0], 10, &amsdu_size);
+ kstrtouint(buffer_array[1], 10, &tid);
+ kstrtouint(buffer_array[2], 10, &total_msdu);
+ kstrtouint(buffer_array[3], 10, &msdu_size);
+
+ if (buffer_array[4])
+ sscanf(buffer_array[4], "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
+ &addr[0], &addr[1], &addr[2], &addr[3], &addr[4], &addr[5]);
+
+ /* Validate all input params*/
+
+ /* Check for AMSDU_size*/
+
+ /* User Inputs*/
+ if (amsdu_size == 0)
+ amsdu_size = AMSDU_SIZE_2K;
+ else if (amsdu_size == 1)
+ amsdu_size = AMSDU_SIZE_4K;
+ else if (amsdu_size == 2)
+ amsdu_size = AMSDU_SIZE_8K;
+ else if (amsdu_size != 0 || amsdu_size != 1 || amsdu_size != 2)
+ amsdu_size = AMSDU_SIZE_2K;
+
+ /* MSDU Size Checks: Min-100, Max: 2304*/
+ if (msdu_size < 0)
+ msdu_size = 100;
+ if (msdu_size > 2304)
+ msdu_size = 2304;
+
+ /* TID CHecks: Default is 0-BE*/
+ if (tid < 0 || tid > 7)
+ tid = 0;/* Default is BE*/
+
+ /* Total MSDU's Checks: Default 3*/
+ if (total_msdu < 0 || total_msdu > 10)
+ total_msdu = 3;
+ /* Driver Inputs: Tx Side*/
+ if ((local->hw.flags & IEEE80211_HW_TX_4K_AMSDU) &&
+ !(local->hw.flags & IEEE80211_HW_TX_8K_AMSDU)) {
+ if (amsdu_size == AMSDU_SIZE_8K)
+ amsdu_size = AMSDU_SIZE_4K;
+ } else if ((local->hw.flags & IEEE80211_HW_TX_8K_AMSDU) &&
+ !(local->hw.flags & IEEE80211_HW_TX_4K_AMSDU)) {
+ /* Take the User Input*/
+ } else if (!(local->hw.flags & IEEE80211_HW_TX_4K_AMSDU) &&
+ !(local->hw.flags & IEEE80211_HW_TX_8K_AMSDU)) {
+ /* Most drivrs are suporting only 2k buffer allocation*/
+ amsdu_size = AMSDU_SIZE_2K;
+ } else if ((local->hw.flags & IEEE80211_HW_TX_4K_AMSDU) &&
+ (local->hw.flags & IEEE80211_HW_TX_8K_AMSDU)) {
+ /* Invalid Case, but just handle it.
+ * Take the User Input
+ */
+ }
+
+ if (!ieee80211_sdata_running(sdata))
+ return -ENOTCONN;
+
+ /* Reciver Inputs: Rx Side
+ * Check the HT Capabilities: Depending on Mode: AP/STA
+ * If user configured 8K but RX doesn't support: Use 4K
+ */
+ switch (sdata->vif.type) {
+ case NL80211_IFTYPE_AP:
+ rcu_read_lock();
+ sta = sta_info_get(sdata, addr);
+ if (!sta) {
+ /* Passed Address is not one of the STAs': Reject*/
+ rcu_read_unlock();
+ return -ENOENT;
+ }
+ if (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_MAX_AMSDU) &&
+ amsdu_size == AMSDU_SIZE_8K)
+ amsdu_size = AMSDU_SIZE_4K;
+ rcu_read_unlock();
+ break;
+ case NL80211_IFTYPE_STATION:
+ rcu_read_lock();
+ mutex_lock(&sdata->u.mgd.mtx);
+ if (!sdata->u.mgd.associated) {
+ mutex_unlock(&sdata->u.mgd.mtx);
+ return -ENOTCONN;
+ }
+ sta = sta_info_get(sdata, sdata->u.mgd.associated->bssid);
+ /*Used later while filling the header*/
+ memcpy(bssid, sdata->u.mgd.associated->bssid, ETH_ALEN);
+ mutex_unlock(&sdata->u.mgd.mtx);
+ if (!sta) {
+ /* Unable to retrive ht.cap info, so fall back to 4K*/
+ amsdu_size = AMSDU_SIZE_4K;
+ } else if (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_MAX_AMSDU)
+ && amsdu_size == AMSDU_SIZE_8K) {
+ amsdu_size = AMSDU_SIZE_4K;
+ }
+ rcu_read_unlock();
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ skb = dev_alloc_skb(local->hw.extra_tx_headroom + amsdu_size + 26);
+ if (!skb)
+ return -ENOMEM;
+
+ skb_reserve(skb, local->hw.extra_tx_headroom);
+ /* Reserve Room for Qos Hdr now, it will be filled later*/
+ hdr = (struct ieee80211_hdr *) skb_put(skb, 26);
+ memset(hdr, 0, 26);
+
+ fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_QOS_DATA);
+
+ switch (sdata->vif.type) {
+ case NL80211_IFTYPE_AP:
+ fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
+ /* DA BSSID SA */
+ memcpy(hdr->addr1, addr, ETH_ALEN);
+ memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
+ memcpy(hdr->addr3, sdata->vif.addr, ETH_ALEN);/*A-MSDU Case*/
+
+ /* Store the Addresses for Subframe AMSDU*/
+ memcpy(daddr, addr, ETH_ALEN);
+ memcpy(saddr, sdata->vif.addr, ETH_ALEN);
+ break;
+ case NL80211_IFTYPE_STATION:
+ fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
+ /* BSSID SA DA */
+ memcpy(hdr->addr1, bssid, ETH_ALEN);
+ memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
+ memcpy(hdr->addr3, bssid, ETH_ALEN); /* A-MSDU Case*/
+
+ /* Store the Addresses for Subframe AMSDU*/
+ memcpy(daddr, addr, ETH_ALEN);
+ memcpy(saddr, sdata->vif.addr, ETH_ALEN);
+ break;
+ default:
+ dev_kfree_skb(skb);
+ return -EOPNOTSUPP;
+ }
+ hdr->frame_control = fc;
+
+ /* Read from the debugfs file and form the AMSDU
+ * Reference: mwifiex driver
+ */
+ payload_size = msdu_size;
+ /*subheader+Reserve+LLC*/
+ msdu_size += AMSDU_SHDR_LEN + AMSDU_RESERVE + LLC_SNAP_LEN;
+ for (num_msdu = 0; num_msdu < total_msdu; num_msdu++) {
+
+ /* Check if there is enough room for
+ * new MSDU
+ */
+ if (skb_tailroom(skb) < (msdu_size))
+ break;
+
+ /* Loop thru and create a AMSDU*/
+ skb_amsdu = dev_alloc_skb(msdu_size);
+ if (!skb_amsdu) {
+ dev_kfree_skb(skb);
+ return -ENOMEM;
+ }
+ /* 4 Byte Alignment..Not required..hence 0*/
+ skb_reserve(skb_amsdu, AMSDU_RESERVE);
+ amsdu_shdr = (struct ieee80211_amsdu_sub_header *)
+ skb_put(skb_amsdu, AMSDU_SHDR_LEN);
+
+ memcpy(amsdu_shdr->daddr, daddr, ETH_ALEN);
+ memcpy(amsdu_shdr->saddr, saddr, ETH_ALEN);
+ /* Doesn't include Subheaders, only MSDU Length*/
+ amsdu_shdr->len = htons(msdu_size-AMSDU_RESERVE-AMSDU_SHDR_LEN);
+
+ /* Add some LLC Header*/
+ memcpy((struct ieee80211_amsdu_llc_hdr *)skb_put(skb_amsdu,
+ LLC_SNAP_LEN) , &amsdu_llc, LLC_SNAP_LEN);
+
+ /* Add Some Payload, as Requested
+ * Add different payload to identify each MSDU in an AMSDU OTA
+ */
+ memset(skb_put(skb_amsdu, payload_size), num_msdu+1,
+ payload_size);
+ if (num_msdu != total_msdu-1) { /* Excpet for the last*/
+ /* pad new MSDU to start at 4 byte boundary*/
+ pad = (4 - ((unsigned long)skb_amsdu->tail & 0x3)) % 4;
+ if (skb_tailroom(skb_amsdu) < pad) {
+ pad = 0;
+ break;
+ }
+ memset(skb_put(skb_amsdu, pad), 0, pad);
+ }
+
+ /* Append to the Main SKB*/
+ memcpy(skb_put(skb, skb_amsdu->len), skb_amsdu->data,
+ skb_amsdu->len);
+ if (!skb_amsdu)
+ dev_kfree_skb(skb_amsdu);
+ }
+ /* The Qos Header changes based on this CTL FLAG*/
+ IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_AMSDU;
+ ieee80211_tx_skb_tid(sdata, skb, tid);
+
+ return buflen;
+}
+__IEEE80211_IF_FILE_W(send_amsdu);
+
static ssize_t ieee80211_if_fmt_uapsd_queues(
const struct ieee80211_sub_if_data *sdata, char *buf, int buflen)
{
@@ -541,6 +797,7 @@ static void add_sta_files(struct
ieee80211_sub_if_data *sdata)
DEBUGFS_ADD(ave_beacon);
DEBUGFS_ADD_MODE(smps, 0600);
DEBUGFS_ADD_MODE(tkip_mic_test, 0200);
+ DEBUGFS_ADD_MODE(send_amsdu, 0200);
DEBUGFS_ADD_MODE(uapsd_queues, 0600);
DEBUGFS_ADD_MODE(uapsd_max_sp_len, 0600);
}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 0fa44a9..be07b6a 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -402,7 +402,6 @@ struct ieee80211_mgd_assoc_data {
bool have_beacon;
bool sent_assoc;
bool synced;
-
u8 ap_ht_param;
struct ieee80211_vht_cap ap_vht_cap;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e930175..9540215 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2183,7 +2183,6 @@ static void ieee80211_destroy_assoc_data(struct
ieee80211_sub_if_data *sdata,
sdata->u.mgd.flags = 0;
ieee80211_vif_release_channel(sdata);
}
-
kfree(assoc_data);
sdata->u.mgd.assoc_data = NULL;
}
@@ -3905,6 +3904,7 @@ int ieee80211_mgd_assoc(struct
ieee80211_sub_if_data *sdata,
assoc_data->supp_rates_len = bss->supp_rates_len;
rcu_read_lock();
+
ht_ie = ieee80211_bss_get_ie(req->bss, WLAN_EID_HT_OPERATION);
if (ht_ie && ht_ie[1] >= sizeof(struct ieee80211_ht_operation))
assoc_data->ap_ht_param =
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index e9eadc4..0c42835 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1144,7 +1144,6 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data
*sdata,
info->flags &= ~IEEE80211_TX_INTFL_NEED_TXPROCESSING;
hdr = (struct ieee80211_hdr *) skb->data;
-
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
tx->sta = rcu_dereference(sdata->u.vlan.sta);
if (!tx->sta && sdata->dev->ieee80211_ptr->use_4addr)
@@ -1327,7 +1326,7 @@ static int invoke_tx_handlers(struct
ieee80211_tx_data *tx)
#define CALL_TXH(txh) \
do { \
res = txh(tx); \
- if (res != TX_CONTINUE) \
+ if (res != TX_CONTINUE) \
goto txh_done; \
} while (0)
@@ -1367,7 +1366,6 @@ static int invoke_tx_handlers(struct
ieee80211_tx_data *tx)
I802_DEBUG_INC(tx->local->tx_handlers_queued);
return -1;
}
-
return 0;
}
diff --git a/net/mac80211/wme.c b/net/mac80211/wme.c
index 906f00c..f444b5d 100644
--- a/net/mac80211/wme.c
+++ b/net/mac80211/wme.c
@@ -188,6 +188,11 @@ void ieee80211_set_qos_hdr(struct
ieee80211_sub_if_data *sdata,
ack_policy |= IEEE80211_QOS_CTL_ACK_POLICY_NOACK;
info->flags |= IEEE80211_TX_CTL_NO_ACK;
}
+ /* Check for AMSDU Injection Tx*/
+ if (info->flags & IEEE80211_TX_CTL_AMSDU) {
+ ack_policy |= IEEE80211_QOS_CTL_A_MSDU_PRESENT;
+ info->flags |= IEEE80211_TX_CTL_DONTFRAG;
+ }
/* qos header is 2 bytes */
*p++ = ack_policy | tid;
On Thu, Feb 7, 2013 at 1:50 PM, Johannes Berg <[email protected]> wrote:
> On Thu, 2013-02-07 at 00:01 -0800, [email protected] wrote:
>
> Hmm. I'm not exactly happy with using (one of) the last control flag for
> a pure debug facility.
>
Hmm...initially i tried to add qos header in the debugfs itself but to avoid
code redundancy went with the TX_CTL. But in either case we need some kind
of flag to skip adding the qos header by mac80211 (or) to set the AMSDU
bit in the qos control header.
> All those spurious whitespace changes just make the patch appear
> longer ... :)
>
Right, will take care of those along with some line wrapping issues while
submitting the patch.
On 2013-02-07 10:30 AM, Krishna Chaitanya wrote:
> On Thu, Feb 7, 2013 at 2:53 PM, Johannes Berg <[email protected]> wrote:
>> On Thu, 2013-02-07 at 14:49 +0530, Krishna Chaitanya wrote:
>>> On Thu, Feb 7, 2013 at 1:50 PM, Johannes Berg <[email protected]> wrote:
>>> > On Thu, 2013-02-07 at 00:01 -0800, [email protected] wrote:
>>> >
>>>
>>> > Hmm. I'm not exactly happy with using (one of) the last control flag for
>>> > a pure debug facility.
>>> >
>>> Hmm...initially i tried to add qos header in the debugfs itself but to avoid
>>> code redundancy went with the TX_CTL. But in either case we need some kind
>>> of flag to skip adding the qos header by mac80211 (or) to set the AMSDU
>>> bit in the qos control header.
>>
>> I guess the question is whether we really need this code in the tree at
>> all? It seems like a (relatively) obscure debug feature for which I'm
>> not sure we should touch the TX fastpath?
>
> AMSDU in itself is rarely used feature in 802.11. So your concern i s
> understandable.
>
> But the problem is every time we have to test the Rx-AMSDU
> which is mandatory for WFA 802.11n cert, we need to procure a adapter
> which supports it, which is difficult. Thats the scenario we have faced
> which lead us to work on this.With this feature in place we can use
> any opensource adapter and driver for that purpose.
>
> Again, Its a trade off between stability and usability :-)
How about injecting A-MSDU packets via cooked monitor mode or nl80211
frame tx and thus shifting the debug-only code into userspace?
- Felix
On Mon, 2013-02-11 at 13:24 +0530, Krishna Chaitanya wrote:
> On Thu, Feb 7, 2013 at 8:57 PM, Johannes Berg <[email protected]> wrote:
> > On Thu, 2013-02-07 at 16:18 +0100, Felix Fietkau wrote:
> >
> >> > But whats the use of sending an AMSDU if we are not connected?
> >> > First check in the code is to check for a connection.
> >> I mentioned cooked monitor because putting the hw in monitor mode may
> >> not always be desirable, and cooked monitor bypasses that.
> >
> > You can pass "flags none" on the iw command line and it shouldn't change
> > much then, but yeah, still might do a few other things. Anyway cooked
> > should work fine.
>
> Even in the cooked monitor case, the setting of qos_header is done
> in the ieee80211_xmit(), so we still need to have some flag to know
> if its an AMSDU/Not based, even if we set the bit in the user space
> this will overwrite that.
You should be able to patch this very easily to preserve the A-MSDU bit,
which won't matter in the normal case where it's always cleared.
johannes
On Thu, 2013-02-07 at 15:03 +0100, Felix Fietkau wrote:
> > But the problem is every time we have to test the Rx-AMSDU
> > which is mandatory for WFA 802.11n cert, we need to procure a adapter
> > which supports it, which is difficult. Thats the scenario we have faced
> > which lead us to work on this.With this feature in place we can use
> > any opensource adapter and driver for that purpose.
> >
> > Again, Its a trade off between stability and usability :-)
> How about injecting A-MSDU packets via cooked monitor mode or nl80211
> frame tx and thus shifting the debug-only code into userspace?
nl80211 won't work -- no support for data frames (and I'd rather not add
it), but monitor mode (why cooked?) seems fine.
johannes
On Mon, Feb 11, 2013 at 2:16 PM, Johannes Berg
<[email protected]> wrote:
> On Mon, 2013-02-11 at 13:24 +0530, Krishna Chaitanya wrote:
>> On Thu, Feb 7, 2013 at 8:57 PM, Johannes Berg <[email protected]> wrote:
>> > On Thu, 2013-02-07 at 16:18 +0100, Felix Fietkau wrote:
> You should be able to patch this very easily to preserve the A-MSDU bit,
> which won't matter in the normal case where it's always cleared.
Will give it a try locally and share the patch. Thanks.
On Thu, 2013-02-07 at 14:49 +0530, Krishna Chaitanya wrote:
> On Thu, Feb 7, 2013 at 1:50 PM, Johannes Berg <[email protected]> wrote:
> > On Thu, 2013-02-07 at 00:01 -0800, [email protected] wrote:
> >
>
> > Hmm. I'm not exactly happy with using (one of) the last control flag for
> > a pure debug facility.
> >
> Hmm...initially i tried to add qos header in the debugfs itself but to avoid
> code redundancy went with the TX_CTL. But in either case we need some kind
> of flag to skip adding the qos header by mac80211 (or) to set the AMSDU
> bit in the qos control header.
I guess the question is whether we really need this code in the tree at
all? It seems like a (relatively) obscure debug feature for which I'm
not sure we should touch the TX fastpath?
johannes
On Thu, 2013-02-07 at 16:18 +0100, Felix Fietkau wrote:
> > But whats the use of sending an AMSDU if we are not connected?
> > First check in the code is to check for a connection.
> I mentioned cooked monitor because putting the hw in monitor mode may
> not always be desirable, and cooked monitor bypasses that.
You can pass "flags none" on the iw command line and it shouldn't change
much then, but yeah, still might do a few other things. Anyway cooked
should work fine.
johannes
On Thu, 2013-02-07 at 00:01 -0800, [email protected] wrote:
> @@ -470,6 +470,7 @@ enum mac80211_tx_control_flags {
> IEEE80211_TX_STATUS_EOSP = BIT(28),
> IEEE80211_TX_CTL_USE_MINRATE = BIT(29),
> IEEE80211_TX_CTL_DONTFRAG = BIT(30),
> + IEEE80211_TX_CTL_AMSDU = BIT(31),
Hmm. I'm not exactly happy with using (one of) the last control flag for
a pure debug facility.
> +++ b/net/mac80211/ieee80211_i.h
> @@ -402,7 +402,6 @@ struct ieee80211_mgd_assoc_data {
> bool have_beacon;
> bool sent_assoc;
> bool synced;
> -
All those spurious whitespace changes just make the patch appear
longer ... :)
johannes
On Thu, Feb 7, 2013 at 6:17 AM, Johannes Berg <[email protected]> wrote:
> On Thu, 2013-02-07 at 15:03 +0100, Felix Fietkau wrote:
>
>> > But the problem is every time we have to test the Rx-AMSDU
>> > which is mandatory for WFA 802.11n cert, we need to procure a adapter
>> > which supports it, which is difficult. Thats the scenario we have faced
>> > which lead us to work on this.With this feature in place we can use
>> > any opensource adapter and driver for that purpose.
>> >
>> > Again, Its a trade off between stability and usability :-)
>> How about injecting A-MSDU packets via cooked monitor mode or nl80211
>> frame tx and thus shifting the debug-only code into userspace?
>
> nl80211 won't work -- no support for data frames (and I'd rather not add
> it), but monitor mode (why cooked?) seems fine.
But whats the use of sending an AMSDU if we are not connected?
First check in the code is to check for a connection.
On Thu, Feb 7, 2013 at 8:57 PM, Johannes Berg <[email protected]> wrote:
> On Thu, 2013-02-07 at 16:18 +0100, Felix Fietkau wrote:
>
>> > But whats the use of sending an AMSDU if we are not connected?
>> > First check in the code is to check for a connection.
>> I mentioned cooked monitor because putting the hw in monitor mode may
>> not always be desirable, and cooked monitor bypasses that.
>
> You can pass "flags none" on the iw command line and it shouldn't change
> much then, but yeah, still might do a few other things. Anyway cooked
> should work fine.
Even in the cooked monitor case, the setting of qos_header is done
in the ieee80211_xmit(), so we still need to have some flag to know
if its an AMSDU/Not based, even if we set the bit in the user space
this will overwrite that.
On Thu, Feb 7, 2013 at 2:53 PM, Johannes Berg <[email protected]> wrote:
> On Thu, 2013-02-07 at 14:49 +0530, Krishna Chaitanya wrote:
>> On Thu, Feb 7, 2013 at 1:50 PM, Johannes Berg <[email protected]> wrote:
>> > On Thu, 2013-02-07 at 00:01 -0800, [email protected] wrote:
>> >
>>
>> > Hmm. I'm not exactly happy with using (one of) the last control flag for
>> > a pure debug facility.
>> >
>> Hmm...initially i tried to add qos header in the debugfs itself but to avoid
>> code redundancy went with the TX_CTL. But in either case we need some kind
>> of flag to skip adding the qos header by mac80211 (or) to set the AMSDU
>> bit in the qos control header.
>
> I guess the question is whether we really need this code in the tree at
> all? It seems like a (relatively) obscure debug feature for which I'm
> not sure we should touch the TX fastpath?
AMSDU in itself is rarely used feature in 802.11. So your concern i s
understandable.
But the problem is every time we have to test the Rx-AMSDU
which is mandatory for WFA 802.11n cert, we need to procure a adapter
which supports it, which is difficult. Thats the scenario we have faced
which lead us to work on this.With this feature in place we can use
any opensource adapter and driver for that purpose.
Again, Its a trade off between stability and usability :-)
On 2013-02-07 3:57 PM, Krishna Chaitanya wrote:
> On Thu, Feb 7, 2013 at 6:17 AM, Johannes Berg <[email protected]> wrote:
>> On Thu, 2013-02-07 at 15:03 +0100, Felix Fietkau wrote:
>>
>>> > But the problem is every time we have to test the Rx-AMSDU
>>> > which is mandatory for WFA 802.11n cert, we need to procure a adapter
>>> > which supports it, which is difficult. Thats the scenario we have faced
>>> > which lead us to work on this.With this feature in place we can use
>>> > any opensource adapter and driver for that purpose.
>>> >
>>> > Again, Its a trade off between stability and usability :-)
>>> How about injecting A-MSDU packets via cooked monitor mode or nl80211
>>> frame tx and thus shifting the debug-only code into userspace?
>>
>> nl80211 won't work -- no support for data frames (and I'd rather not add
>> it), but monitor mode (why cooked?) seems fine.
>
> But whats the use of sending an AMSDU if we are not connected?
> First check in the code is to check for a connection.
I mentioned cooked monitor because putting the hw in monitor mode may
not always be desirable, and cooked monitor bypasses that.
You can send the AMSDU while you're connected. mac80211 treats injected
frames that match the address of a local interface similar to regular tx
on that interface, except for bypassing the normal 802.11 header
encapsulation, so it should work for your tests.
- Felix