net/batman-adv/fragmentation.c

31  * batadv_frag_clear_chain() - delete entries in the fragment buffer chain
32  * @head: head of chain with entries.
33  * @dropped: whether the chain is cleared because all fragments are dropped
62 	struct batadv_frag_table_entry *chain;
66 		chain = &orig_node->fragments[i];
67 		spin_lock_bh(&chain->lock);
69 		if (!check_cb || check_cb(chain)) {
70 			batadv_frag_clear_chain(&chain->fragment_list, true);
71 			chain->size = 0;
74 		spin_unlock_bh(&chain->lock);
94  * batadv_frag_init_chain() - check and prepare fragment chain for new fragment
95  * @chain: chain in fragments table to init
98  * Make chain ready for a fragment with sequence number "seqno". Delete existing
101  * Caller must hold chain->lock.
103  * Return: true if chain is empty and the caller can just insert the new
106 static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
109 	lockdep_assert_held(&chain->lock);
111 	if (chain->seqno == seqno)
114 	if (!hlist_empty(&chain->fragment_list))
115 		batadv_frag_clear_chain(&chain->fragment_list, true);
117 	chain->size = 0;
118 	chain->seqno = seqno;
124  * batadv_frag_insert_packet() - insert a fragment into a fragment chain
129  * Insert a new fragment into the reverse ordered chain in the right table
132  * Return: true if skb is buffered, false on error. If the chain has all the
133  * fragments needed to merge the packet, the chain is moved to the passed head
134  * to avoid locking the chain in the table.
140 	struct batadv_frag_table_entry *chain;
166 	/* Select entry in the "chain table" and delete any prior fragments
170 	chain = &orig_node->fragments[bucket];
171 	spin_lock_bh(&chain->lock);
172 	if (batadv_frag_init_chain(chain, seqno)) {
173 		hlist_add_head(&frag_entry_new->list, &chain->fragment_list);
174 		chain->size = skb->len - hdr_size;
175 		chain->timestamp = jiffies;
176 		chain->total_size = ntohs(frag_packet->total_size);
182 	hlist_for_each_entry(frag_entry_curr, &chain->fragment_list, list) {
191 			chain->size += skb->len - hdr_size;
192 			chain->timestamp = jiffies;
204 		chain->size += skb->len - hdr_size;
205 		chain->timestamp = jiffies;
210 	if (chain->size > batadv_frag_size_limit() ||
211 	    chain->total_size != ntohs(frag_packet->total_size) ||
212 	    chain->total_size > batadv_frag_size_limit()) {
213 		/* Clear chain if total size of either the list or the packet
217 		batadv_frag_clear_chain(&chain->fragment_list, true);
218 		chain->size = 0;
219 	} else if (ntohs(frag_packet->total_size) == chain->size) {
220 		/* All fragments received. Hand over chain to caller. */
221 		hlist_move_list(&chain->fragment_list, chain_out);
222 		chain->size = 0;
226 	spin_unlock_bh(&chain->lock);
238  * batadv_frag_merge_packets() - merge a chain of fragments
239  * @chain: head of chain with fragments
241  * Expand the first skb in the chain and copy the content of the remaining
242  * skb's into the expanded one. After doing so, clear the chain.
247 batadv_frag_merge_packets(struct hlist_head *chain)
258 	entry = hlist_entry(chain->first, struct batadv_frag_list_entry, list);
285 	hlist_for_each_entry(entry, chain, list) {
291 	/* Locking is not needed, because 'chain' is not part of any orig. */
292 	batadv_frag_clear_chain(chain, dropped);