mac80211: optimise monitor xmit

Since the only way the interface can be a monitor
interface in ieee80211_xmit() is because the frame
came from ieee80211_monitor_start_xmit() we can
move all the code there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ad2ee4a..84ebc3f 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1539,55 +1539,11 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
-       struct ieee80211_sub_if_data *tmp_sdata;
        int headroom;
        bool may_encrypt;
 
        rcu_read_lock();
 
-       if (unlikely(sdata->vif.type == NL80211_IFTYPE_MONITOR)) {
-               int hdrlen;
-               u16 len_rthdr;
-
-               info->flags |= IEEE80211_TX_CTL_INJECTED |
-                              IEEE80211_TX_INTFL_HAS_RADIOTAP;
-
-               len_rthdr = ieee80211_get_radiotap_len(skb->data);
-               hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
-               hdrlen = ieee80211_hdrlen(hdr->frame_control);
-
-               /* check the header is complete in the frame */
-               if (likely(skb->len >= len_rthdr + hdrlen)) {
-                       /*
-                        * We process outgoing injected frames that have a
-                        * local address we handle as though they are our
-                        * own frames.
-                        * This code here isn't entirely correct, the local
-                        * MAC address is not necessarily enough to find
-                        * the interface to use; for that proper VLAN/WDS
-                        * support we will need a different mechanism.
-                        */
-
-                       list_for_each_entry_rcu(tmp_sdata, &local->interfaces,
-                                               list) {
-                               if (!ieee80211_sdata_running(tmp_sdata))
-                                       continue;
-                               if (tmp_sdata->vif.type ==
-                                   NL80211_IFTYPE_MONITOR ||
-                                   tmp_sdata->vif.type ==
-                                   NL80211_IFTYPE_AP_VLAN ||
-                                       tmp_sdata->vif.type ==
-                                   NL80211_IFTYPE_WDS)
-                                       continue;
-                               if (compare_ether_addr(tmp_sdata->vif.addr,
-                                                      hdr->addr2) == 0) {
-                                       sdata = tmp_sdata;
-                                       break;
-                               }
-                       }
-               }
-       }
-
        may_encrypt = !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT);
 
        headroom = local->tx_headroom;
@@ -1628,8 +1584,9 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
                (struct ieee80211_radiotap_header *)skb->data;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct ieee80211_hdr *hdr;
+       struct ieee80211_sub_if_data *tmp_sdata, *sdata;
        u16 len_rthdr;
-       u8 *payload;
+       int hdrlen;
 
        /*
         * Frame injection is not allowed if beaconing is not allowed
@@ -1680,30 +1637,63 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
        skb_set_network_header(skb, len_rthdr);
        skb_set_transport_header(skb, len_rthdr);
 
+       if (skb->len < len_rthdr + 2)
+               goto fail;
+
+       hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
+       hdrlen = ieee80211_hdrlen(hdr->frame_control);
+
+       if (skb->len < len_rthdr + hdrlen)
+               goto fail;
+
        /*
         * Initialize skb->protocol if the injected frame is a data frame
         * carrying a rfc1042 header
         */
-       if (skb->len > len_rthdr + 2) {
-               hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
-               if (ieee80211_is_data(hdr->frame_control) &&
-                   skb->len >= len_rthdr +
-                               ieee80211_hdrlen(hdr->frame_control) +
-                               sizeof(rfc1042_header) + 2) {
-                       payload = (u8 *)hdr +
-                                 ieee80211_hdrlen(hdr->frame_control);
-                       if (compare_ether_addr(payload, rfc1042_header) == 0)
-                               skb->protocol = cpu_to_be16((payload[6] << 8) |
-                                                           payload[7]);
-               }
+       if (ieee80211_is_data(hdr->frame_control) &&
+           skb->len >= len_rthdr + hdrlen + sizeof(rfc1042_header) + 2) {
+               u8 *payload = (u8 *)hdr + hdrlen;
+
+               if (compare_ether_addr(payload, rfc1042_header) == 0)
+                       skb->protocol = cpu_to_be16((payload[6] << 8) |
+                                                   payload[7]);
        }
 
        memset(info, 0, sizeof(*info));
 
-       info->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
+       info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
+                     IEEE80211_TX_CTL_INJECTED |
+                     IEEE80211_TX_INTFL_HAS_RADIOTAP;
+
+       rcu_read_lock();
+
+       /*
+        * We process outgoing injected frames that have a local address
+        * we handle as though they are non-injected frames.
+        * This code here isn't entirely correct, the local MAC address
+        * isn't always enough to find the interface to use; for proper
+        * VLAN/WDS support we will need a different mechanism (which
+        * likely isn't going to be monitor interfaces).
+        */
+       sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+       list_for_each_entry_rcu(tmp_sdata, &local->interfaces, list) {
+               if (!ieee80211_sdata_running(tmp_sdata))
+                       continue;
+               if (tmp_sdata->vif.type == NL80211_IFTYPE_MONITOR ||
+                   tmp_sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
+                   tmp_sdata->vif.type == NL80211_IFTYPE_WDS)
+                       continue;
+               if (compare_ether_addr(tmp_sdata->vif.addr, hdr->addr2) == 0) {
+                       sdata = tmp_sdata;
+                       break;
+               }
+       }
 
        /* pass the radiotap header up to xmit */
-       ieee80211_xmit(IEEE80211_DEV_TO_SUB_IF(dev), skb);
+       ieee80211_xmit(sdata, skb);
+       rcu_read_unlock();
+
        return NETDEV_TX_OK;
 
 fail: