+static int ieee80211_fragment(struct ieee80211_local *local,
+ struct sk_buff *skb, int hdrlen,
+ int frag_threshold)
+{
+ struct sk_buff *tail = skb, *tmp;
+ int per_fragm = frag_threshold - hdrlen - FCS_LEN;
+ int pos = hdrlen + per_fragm;
+ int rem = skb->len - hdrlen - per_fragm;
+
+ if (WARN_ON(rem < 0))
+ return -EINVAL;
+
+ while (rem) {
+ int fraglen = per_fragm;
+
+ if (fraglen > rem)
+ fraglen = rem;
+ rem -= fraglen;
+ tmp = dev_alloc_skb(local->tx_headroom +
+ frag_threshold +
+ IEEE80211_ENCRYPT_HEADROOM +
+ IEEE80211_ENCRYPT_TAILROOM);
+ if (!tmp)
+ return -ENOMEM;
+ tail->next = tmp;
+ tail = tmp;
+ skb_reserve(tmp, local->tx_headroom +
+ IEEE80211_ENCRYPT_HEADROOM);
+ /* copy control information */
+ memcpy(tmp->cb, skb->cb, sizeof(tmp->cb));
+ skb_copy_queue_mapping(tmp, skb);
+ tmp->priority = skb->priority;
+ tmp->do_not_encrypt = skb->do_not_encrypt;
+ tmp->dev = skb->dev;
+ tmp->iif = skb->iif;
+
+ /* copy header and data */
+ memcpy(skb_put(tmp, hdrlen), skb->data, hdrlen);
+ memcpy(skb_put(tmp, fraglen), skb->data + pos, fraglen);
+
+ pos += fraglen;
+ }
+
+ skb->len = hdrlen + per_fragm;
+ return 0;
+}
+