diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 2142074d9fb0..0094f3c0af64 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -533,6 +533,59 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local, } } +static struct sk_buff * +ieee80211_make_monitor_skb(struct ieee80211_local *local, + struct sk_buff **origskb, + struct ieee80211_rate *rate, + int rtap_vendor_space, bool use_origskb) +{ + struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(*origskb); + int rt_hdrlen, needed_headroom; + struct sk_buff *skb; + + /* room for the radiotap header based on driver features */ + rt_hdrlen = ieee80211_rx_radiotap_hdrlen(local, status, *origskb); + needed_headroom = rt_hdrlen - rtap_vendor_space; + + if (use_origskb) { + /* only need to expand headroom if necessary */ + skb = *origskb; + *origskb = NULL; + + /* + * This shouldn't trigger often because most devices have an + * RX header they pull before we get here, and that should + * be big enough for our radiotap information. We should + * probably export the length to drivers so that we can have + * them allocate enough headroom to start with. + */ + if (skb_headroom(skb) < needed_headroom && + pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) { + dev_kfree_skb(skb); + return NULL; + } + } else { + /* + * Need to make a copy and possibly remove radiotap header + * and FCS from the original. + */ + skb = skb_copy_expand(*origskb, needed_headroom, 0, GFP_ATOMIC); + + if (!skb) + return NULL; + } + + /* prepend radiotap information */ + ieee80211_add_rx_radiotap_header(local, skb, rate, rt_hdrlen, true); + + skb_reset_mac_header(skb); + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->pkt_type = PACKET_OTHERHOST; + skb->protocol = htons(ETH_P_802_2); + + return skb; +} + /* * This function copies a received frame to all monitor interfaces and * returns a cleaned-up SKB that no longer includes the FCS nor the @@ -544,13 +597,12 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, { struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb); struct ieee80211_sub_if_data *sdata; - int rt_hdrlen, needed_headroom; - struct sk_buff *skb, *skb2; - struct net_device *prev_dev = NULL; + struct sk_buff *monskb = NULL; int present_fcs_len = 0; unsigned int rtap_vendor_space = 0; struct ieee80211_sub_if_data *monitor_sdata = rcu_dereference(local->monitor_sdata); + bool only_monitor = false; if (unlikely(status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA)) { struct ieee80211_vendor_radiotap *rtap = (void *)origskb->data; @@ -583,9 +635,11 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, return NULL; } + only_monitor = should_drop_frame(origskb, present_fcs_len, + rtap_vendor_space); + if (!local->monitors || (status->flag & RX_FLAG_SKIP_MONITOR)) { - if (should_drop_frame(origskb, present_fcs_len, - rtap_vendor_space)) { + if (only_monitor) { dev_kfree_skb(origskb); return NULL; } @@ -597,67 +651,46 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb, ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_vendor_space); - /* room for the radiotap header based on driver features */ - rt_hdrlen = ieee80211_rx_radiotap_hdrlen(local, status, origskb); - needed_headroom = rt_hdrlen - rtap_vendor_space; - - if (should_drop_frame(origskb, present_fcs_len, rtap_vendor_space)) { - /* only need to expand headroom if necessary */ - skb = origskb; - origskb = NULL; - - /* - * This shouldn't trigger often because most devices have an - * RX header they pull before we get here, and that should - * be big enough for our radiotap information. We should - * probably export the length to drivers so that we can have - * them allocate enough headroom to start with. - */ - if (skb_headroom(skb) < needed_headroom && - pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) { - dev_kfree_skb(skb); - return NULL; - } - } else { - /* - * Need to make a copy and possibly remove radiotap header - * and FCS from the original. - */ - skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC); - remove_monitor_info(origskb, present_fcs_len, - rtap_vendor_space); - - if (!skb) - return origskb; - } - - /* prepend radiotap information */ - ieee80211_add_rx_radiotap_header(local, skb, rate, rt_hdrlen, true); - - skb_reset_mac_header(skb); - skb->ip_summed = CHECKSUM_UNNECESSARY; - skb->pkt_type = PACKET_OTHERHOST; - skb->protocol = htons(ETH_P_802_2); - list_for_each_entry_rcu(sdata, &local->mon_list, u.mntr.list) { - if (prev_dev) { - skb2 = skb_clone(skb, GFP_ATOMIC); - if (skb2) { - skb2->dev = prev_dev; - netif_receive_skb(skb2); + bool last_monitor = list_is_last(&sdata->u.mntr.list, + &local->mon_list); + + if (!monskb) + monskb = ieee80211_make_monitor_skb(local, &origskb, + rate, + rtap_vendor_space, + only_monitor && + last_monitor); + + if (monskb) { + struct sk_buff *skb; + + if (last_monitor) { + skb = monskb; + monskb = NULL; + } else { + skb = skb_clone(monskb, GFP_ATOMIC); + } + + if (skb) { + skb->dev = sdata->dev; + ieee80211_rx_stats(skb->dev, skb->len); + netif_receive_skb(skb); } } - prev_dev = sdata->dev; - ieee80211_rx_stats(sdata->dev, skb->len); + if (last_monitor) + break; } - if (prev_dev) { - skb->dev = prev_dev; - netif_receive_skb(skb); - } else - dev_kfree_skb(skb); + /* this happens if last_monitor was erroneously false */ + dev_kfree_skb(monskb); + /* ditto */ + if (!origskb) + return NULL; + + remove_monitor_info(origskb, present_fcs_len, rtap_vendor_space); return origskb; }