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>

1 files changed, 49 insertions, 59 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ad2ee4a90ec4..84ebc3f89123 100644
--- 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: