package/kernel/mac80211/patches/320-cfg80211-add-support-for-non-linear-skbs-in-ieee8021.patch

   1 From: Felix Fietkau <nbd@openwrt.org>
   2 Date: Tue, 2 Feb 2016 14:39:10 +0100
   3 Subject: [PATCH] cfg80211: add support for non-linear skbs in
   4  ieee80211_amsdu_to_8023s
   5
   6 Signed-off-by: Felix Fietkau <nbd@openwrt.org>
   7 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
   8 ---
   9
  10 --- a/net/wireless/util.c
  11 +++ b/net/wireless/util.c
  12 @@ -644,73 +644,75 @@ int ieee80211_data_from_8023(struct sk_b
  13  }
  14  EXPORT_SYMBOL(ieee80211_data_from_8023);
  15
  16 +static struct sk_buff *
  17 +__ieee80211_amsdu_copy(struct sk_buff *skb, unsigned int hlen,
  18 +                      int offset, int len)
  19 +{
  20 +       struct sk_buff *frame;
  21 +
  22 +       if (skb->len - offset < len)
  23 +               return NULL;
  24 +
  25 +       /*
  26 +        * Allocate and reserve two bytes more for payload
  27 +        * alignment since sizeof(struct ethhdr) is 14.
  28 +        */
  29 +       frame = dev_alloc_skb(hlen + sizeof(struct ethhdr) + 2 + len);
  30 +
  31 +       skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
  32 +       skb_copy_bits(skb, offset, skb_put(frame, len), len);
  33 +
  34 +       return frame;
  35 +}
  36
  37  void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
  38                               const u8 *addr, enum nl80211_iftype iftype,
  39                               const unsigned int extra_headroom,
  40                               bool has_80211_header)
  41  {
  42 +       unsigned int hlen = ALIGN(extra_headroom, 4);
  43         struct sk_buff *frame = NULL;
  44         u16 ethertype;
  45         u8 *payload;
  46 -       const struct ethhdr *eth;
  47 -       int remaining, err;
  48 -       u8 dst[ETH_ALEN], src[ETH_ALEN];
  49 -
  50 -       if (skb_linearize(skb))
  51 -               goto out;
  52 +       int offset = 0, remaining, err;
  53 +       struct ethhdr eth;
  54 +       bool reuse_skb = true;
  55 +       bool last = false;
  56
  57         if (has_80211_header) {
  58 -               err = ieee80211_data_to_8023(skb, addr, iftype);
  59 +               err = __ieee80211_data_to_8023(skb, &eth, addr, iftype);
  60                 if (err)
  61                         goto out;
  62 -
  63 -               /* skip the wrapping header */
  64 -               eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
  65 -               if (!eth)
  66 -                       goto out;
  67 -       } else {
  68 -               eth = (struct ethhdr *) skb->data;
  69         }
  70
  71 -       while (skb != frame) {
  72 +       while (!last) {
  73 +               unsigned int subframe_len;
  74 +               int len;
  75                 u8 padding;
  76 -               __be16 len = eth->h_proto;
  77 -               unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
  78 -
  79 -               remaining = skb->len;
  80 -               memcpy(dst, eth->h_dest, ETH_ALEN);
  81 -               memcpy(src, eth->h_source, ETH_ALEN);
  82
  83 +               skb_copy_bits(skb, offset, &eth, sizeof(eth));
  84 +               len = ntohs(eth.h_proto);
  85 +               subframe_len = sizeof(struct ethhdr) + len;
  86                 padding = (4 - subframe_len) & 0x3;
  87 +
  88                 /* the last MSDU has no padding */
  89 +               remaining = skb->len - offset;
  90                 if (subframe_len > remaining)
  91                         goto purge;
  92
  93 -               skb_pull(skb, sizeof(struct ethhdr));
  94 +               offset += sizeof(struct ethhdr);
  95                 /* reuse skb for the last subframe */
  96 -               if (remaining <= subframe_len + padding)
  97 +               last = remaining <= subframe_len + padding;
  98 +               if (!skb_is_nonlinear(skb) && last) {
  99 +                       skb_pull(skb, offset);
 100                         frame = skb;
 101 -               else {
 102 -                       unsigned int hlen = ALIGN(extra_headroom, 4);
 103 -                       /*
 104 -                        * Allocate and reserve two bytes more for payload
 105 -                        * alignment since sizeof(struct ethhdr) is 14.
 106 -                        */
 107 -                       frame = dev_alloc_skb(hlen + subframe_len + 2);
 108 +                       reuse_skb = true;
 109 +               } else {
 110 +                       frame = __ieee80211_amsdu_copy(skb, hlen, offset, len);
 111                         if (!frame)
 112                                 goto purge;
 113
 114 -                       skb_reserve(frame, hlen + sizeof(struct ethhdr) + 2);
 115 -                       memcpy(skb_put(frame, ntohs(len)), skb->data,
 116 -                               ntohs(len));
 117 -
 118 -                       eth = (struct ethhdr *)skb_pull(skb, ntohs(len) +
 119 -                                                       padding);
 120 -                       if (!eth) {
 121 -                               dev_kfree_skb(frame);
 122 -                               goto purge;
 123 -                       }
 124 +                       offset += len + padding;
 125                 }
 126
 127                 skb_reset_network_header(frame);
 128 @@ -719,24 +721,20 @@ void ieee80211_amsdu_to_8023s(struct sk_
 129
 130                 payload = frame->data;
 131                 ethertype = (payload[6] << 8) | payload[7];
 132 -
 133                 if (likely((ether_addr_equal(payload, rfc1042_header) &&
 134                             ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
 135                            ether_addr_equal(payload, bridge_tunnel_header))) {
 136 -                       /* remove RFC1042 or Bridge-Tunnel
 137 -                        * encapsulation and replace EtherType */
 138 -                       skb_pull(frame, 6);
 139 -                       memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
 140 -                       memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
 141 -               } else {
 142 -                       memcpy(skb_push(frame, sizeof(__be16)), &len,
 143 -                               sizeof(__be16));
 144 -                       memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
 145 -                       memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
 146 +                       eth.h_proto = htons(ethertype);
 147 +                       skb_pull(frame, ETH_ALEN + 2);
 148                 }
 149 +
 150 +               memcpy(skb_push(frame, sizeof(eth)), &eth, sizeof(eth));
 151                 __skb_queue_tail(list, frame);
 152         }
 153
 154 +       if (!reuse_skb)
 155 +               dev_kfree_skb(skb);
 156 +
 157         return;
 158
 159   purge: