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mac80211: factor out 802.11 header building code
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Factor out the 802.11 header building code from the xmit function
to be able to use it separately in a later commit.

While at it, fix up some documentation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Johannes Berg committed Nov 19, 2014
1 parent 73c4e19 commit 4c9451e
Showing 1 changed file with 92 additions and 52 deletions.
144 changes: 92 additions & 52 deletions net/mac80211/tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1784,24 +1784,26 @@ static void ieee80211_tx_latency_start_msrmnt(struct ieee80211_local *local,
}

/**
* __ieee80211_subif_start_xmit - netif start_xmit function for Ethernet-type
* subinterfaces (wlan#, WDS, and VLAN interfaces)
* @skb: packet to be sent
* @dev: incoming interface
* ieee80211_build_hdr - build 802.11 header in the given frame
* @sdata: virtual interface to build the header for
* @skb: the skb to build the header in
* @info_flags: skb flags to set
*
* On failure skb will be freed.
* This function takes the skb with 802.3 header and reformats the header to
* the appropriate IEEE 802.11 header based on which interface the packet is
* being transmitted on.
*
* Note that this function also takes care of the TX status request and
* potential unsharing of the SKB - this needs to be interleaved with the
* header building.
*
* The function requires the read-side RCU lock held
*
* This function takes in an Ethernet header and encapsulates it with suitable
* IEEE 802.11 header based on which interface the packet is coming in. The
* encapsulated packet will then be passed to master interface, wlan#.11, for
* transmission (through low-level driver).
* Returns: the (possibly reallocated) skb or an ERR_PTR() code
*/
void __ieee80211_subif_start_xmit(struct sk_buff *skb,
struct net_device *dev,
u32 info_flags)
static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb, u32 info_flags)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;
struct ieee80211_tx_info *info;
int head_need;
Expand All @@ -1821,20 +1823,13 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
struct ieee80211_chanctx_conf *chanctx_conf;
struct ieee80211_sub_if_data *ap_sdata;
enum ieee80211_band band;

if (unlikely(skb->len < ETH_HLEN))
goto fail;
int ret;

/* convert Ethernet header to proper 802.11 header (based on
* operation mode) */
ethertype = (skb->data[12] << 8) | skb->data[13];
fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);

rcu_read_lock();

/* Measure frame arrival for Tx latency statistics calculation */
ieee80211_tx_latency_start_msrmnt(local, skb);

switch (sdata->vif.type) {
case NL80211_IFTYPE_AP_VLAN:
sta = rcu_dereference(sdata->u.vlan.sta);
Expand All @@ -1852,17 +1847,21 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
ap_sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
u.ap);
chanctx_conf = rcu_dereference(ap_sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
band = chanctx_conf->def.chan->band;
if (sta)
break;
/* fall through */
case NL80211_IFTYPE_AP:
if (sdata->vif.type == NL80211_IFTYPE_AP)
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
/* DA BSSID SA */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
Expand Down Expand Up @@ -1949,8 +1948,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,

}
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
band = chanctx_conf->def.chan->band;
break;
#endif
Expand Down Expand Up @@ -1980,8 +1981,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
* of a link teardown after a TDLS sta is removed due to being
* unreachable.
*/
if (tdls_peer && !tdls_auth && !tdls_setup_frame)
goto fail_rcu;
if (tdls_peer && !tdls_auth && !tdls_setup_frame) {
ret = -EINVAL;
goto free;
}

/* send direct packets to authorized TDLS peers */
if (tdls_peer && tdls_auth) {
Expand Down Expand Up @@ -2009,8 +2012,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
hdrlen = 24;
}
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
band = chanctx_conf->def.chan->band;
break;
case NL80211_IFTYPE_OCB:
Expand All @@ -2020,8 +2025,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
eth_broadcast_addr(hdr.addr3);
hdrlen = 24;
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
band = chanctx_conf->def.chan->band;
break;
case NL80211_IFTYPE_ADHOC:
Expand All @@ -2031,12 +2038,15 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
memcpy(hdr.addr3, sdata->u.ibss.bssid, ETH_ALEN);
hdrlen = 24;
chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
if (!chanctx_conf)
goto fail_rcu;
if (!chanctx_conf) {
ret = -ENOTCONN;
goto free;
}
band = chanctx_conf->def.chan->band;
break;
default:
goto fail_rcu;
ret = -EINVAL;
goto free;
}

/*
Expand Down Expand Up @@ -2074,12 +2084,13 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
!ether_addr_equal(sdata->vif.addr, skb->data + ETH_ALEN)))) {
#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
net_info_ratelimited("%s: dropped frame to %pM (unauthorized port)\n",
dev->name, hdr.addr1);
sdata->name, hdr.addr1);
#endif

I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);

goto fail_rcu;
ret = -EPERM;
goto free;
}

if (unlikely(!multicast && skb->sk &&
Expand Down Expand Up @@ -2116,8 +2127,10 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
skb = skb_clone(skb, GFP_ATOMIC);
kfree_skb(tmp_skb);

if (!skb)
goto fail_rcu;
if (!skb) {
ret = -ENOMEM;
goto free;
}
}

hdr.frame_control = fc;
Expand Down Expand Up @@ -2166,7 +2179,7 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
if (ieee80211_skb_resize(sdata, skb, head_need, true)) {
ieee80211_free_txskb(&local->hw, skb);
skb = NULL;
goto fail_rcu;
return ERR_PTR(-ENOMEM);
}
}

Expand Down Expand Up @@ -2200,9 +2213,6 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
nh_pos += hdrlen;
h_pos += hdrlen;

dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;

/* Update skb pointers to various headers since this modified frame
* is going to go through Linux networking code that may potentially
* need things like pointer to IP header. */
Expand All @@ -2213,23 +2223,53 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
info = IEEE80211_SKB_CB(skb);
memset(info, 0, sizeof(*info));

dev->trans_start = jiffies;

info->flags = info_flags;
info->ack_frame_id = info_id;
info->band = band;

ieee80211_xmit(sdata, skb);
rcu_read_unlock();
return skb;
free:
kfree_skb(skb);
return ERR_PTR(ret);
}

void __ieee80211_subif_start_xmit(struct sk_buff *skb,
struct net_device *dev,
u32 info_flags)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct ieee80211_local *local = sdata->local;

if (unlikely(skb->len < ETH_HLEN)) {
kfree_skb(skb);
return;
}

rcu_read_lock();

/* Measure frame arrival for Tx latency statistics calculation */
ieee80211_tx_latency_start_msrmnt(local, skb);

skb = ieee80211_build_hdr(sdata, skb, info_flags);
if (IS_ERR(skb))
goto out;

return;
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
dev->trans_start = jiffies;

fail_rcu:
ieee80211_xmit(sdata, skb);
out:
rcu_read_unlock();
fail:
dev_kfree_skb(skb);
}

/**
* ieee80211_subif_start_xmit - netif start_xmit function for 802.3 vifs
* @skb: packet to be sent
* @dev: incoming interface
*
* On failure skb will be freed.
*/
netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
Expand Down

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