1 // SPDX-License-Identifier: GPL-2.0
26 #include "hard-interface.h"
32  * batadv_frag_clear_chain() - delete entries in the fragment buffer chain
44 		hlist_del(&entry->list);  in batadv_frag_clear_chain()
47 			kfree_skb(entry->skb);  in batadv_frag_clear_chain()
49 			consume_skb(entry->skb);  in batadv_frag_clear_chain()
56  * batadv_frag_purge_orig() - free fragments associated to an orig
67 		chain = &orig_node->fragments[i];  in batadv_frag_purge_orig()
68 		spin_lock_bh(&chain->lock);  in batadv_frag_purge_orig()
71 			batadv_frag_clear_chain(&chain->fragment_list, true);  in batadv_frag_purge_orig()
72 			chain->size = 0;  in batadv_frag_purge_orig()
75 		spin_unlock_bh(&chain->lock);  in batadv_frag_purge_orig()
80  * batadv_frag_size_limit() - maximum possible size of packet to be fragmented
88 	limit -= sizeof(struct batadv_frag_packet);  in batadv_frag_size_limit()
95  * batadv_frag_init_chain() - check and prepare fragment chain for new fragment
102  * Caller must hold chain->lock.
110 	lockdep_assert_held(&chain->lock);  in batadv_frag_init_chain()
112 	if (chain->seqno == seqno)  in batadv_frag_init_chain()
115 	if (!hlist_empty(&chain->fragment_list))  in batadv_frag_init_chain()
116 		batadv_frag_clear_chain(&chain->fragment_list, true);  in batadv_frag_init_chain()
118 	chain->size = 0;  in batadv_frag_init_chain()
119 	chain->seqno = seqno;  in batadv_frag_init_chain()
125  * batadv_frag_insert_packet() - insert a fragment into a fragment chain
133  * Return: true if skb is buffered, false on error. If the chain has all the
150 	 * the later merge. Non-linear merge should be added to remove this  in batadv_frag_insert_packet()
156 	frag_packet = (struct batadv_frag_packet *)skb->data;  in batadv_frag_insert_packet()
157 	seqno = ntohs(frag_packet->seqno);  in batadv_frag_insert_packet()
164 	frag_entry_new->skb = skb;  in batadv_frag_insert_packet()
165 	frag_entry_new->no = frag_packet->no;  in batadv_frag_insert_packet()
171 	chain = &orig_node->fragments[bucket];  in batadv_frag_insert_packet()
172 	spin_lock_bh(&chain->lock);  in batadv_frag_insert_packet()
174 		hlist_add_head(&frag_entry_new->list, &chain->fragment_list);  in batadv_frag_insert_packet()
175 		chain->size = skb->len - hdr_size;  in batadv_frag_insert_packet()
176 		chain->timestamp = jiffies;  in batadv_frag_insert_packet()
177 		chain->total_size = ntohs(frag_packet->total_size);  in batadv_frag_insert_packet()
183 	hlist_for_each_entry(frag_entry_curr, &chain->fragment_list, list) {  in batadv_frag_insert_packet()
185 		if (frag_entry_curr->no == frag_entry_new->no)  in batadv_frag_insert_packet()
189 		if (frag_entry_curr->no < frag_entry_new->no) {  in batadv_frag_insert_packet()
190 			hlist_add_before(&frag_entry_new->list,  in batadv_frag_insert_packet()
191 					 &frag_entry_curr->list);  in batadv_frag_insert_packet()
192 			chain->size += skb->len - hdr_size;  in batadv_frag_insert_packet()
193 			chain->timestamp = jiffies;  in batadv_frag_insert_packet()
204 		hlist_add_behind(&frag_entry_new->list, &frag_entry_last->list);  in batadv_frag_insert_packet()
205 		chain->size += skb->len - hdr_size;  in batadv_frag_insert_packet()
206 		chain->timestamp = jiffies;  in batadv_frag_insert_packet()
211 	if (chain->size > batadv_frag_size_limit() ||  in batadv_frag_insert_packet()
212 	    chain->total_size != ntohs(frag_packet->total_size) ||  in batadv_frag_insert_packet()
213 	    chain->total_size > batadv_frag_size_limit()) {  in batadv_frag_insert_packet()
218 		batadv_frag_clear_chain(&chain->fragment_list, true);  in batadv_frag_insert_packet()
219 		chain->size = 0;  in batadv_frag_insert_packet()
220 	} else if (ntohs(frag_packet->total_size) == chain->size) {  in batadv_frag_insert_packet()
222 		hlist_move_list(&chain->fragment_list, chain_out);  in batadv_frag_insert_packet()
223 		chain->size = 0;  in batadv_frag_insert_packet()
227 	spin_unlock_bh(&chain->lock);  in batadv_frag_insert_packet()
239  * batadv_frag_merge_packets() - merge a chain of fragments
259 	entry = hlist_entry(chain->first, struct batadv_frag_list_entry, list);  in batadv_frag_merge_packets()
260 	hlist_del(&entry->list);  in batadv_frag_merge_packets()
261 	skb_out = entry->skb;  in batadv_frag_merge_packets()
264 	packet = (struct batadv_frag_packet *)skb_out->data;  in batadv_frag_merge_packets()
265 	size = ntohs(packet->total_size) + hdr_size;  in batadv_frag_merge_packets()
268 	if (pskb_expand_head(skb_out, 0, size - skb_out->len, GFP_ATOMIC) < 0) {  in batadv_frag_merge_packets()
279 	skb_out->ip_summed = CHECKSUM_NONE;  in batadv_frag_merge_packets()
280 	memmove(skb_out->data - ETH_HLEN, skb_mac_header(skb_out), ETH_HLEN);  in batadv_frag_merge_packets()
281 	skb_set_mac_header(skb_out, -ETH_HLEN);  in batadv_frag_merge_packets()
287 		size = entry->skb->len - hdr_size;  in batadv_frag_merge_packets()
288 		skb_put_data(skb_out, entry->skb->data + hdr_size, size);  in batadv_frag_merge_packets()
298  * batadv_frag_skb_buffer() - buffer fragment for later merge
305  * set *skb to merged packet; 2) Packet is buffered: Return true and set *skb
308  * Return: true when the packet is merged or buffered, false when skb is not
338  * batadv_frag_skb_fwd() - forward fragments that would exceed MTU when merged
343  * Look up the next-hop of the fragments payload and check if the merged packet
344  * will exceed the MTU towards the next-hop. If so, the fragment is forwarded
353 	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);  in batadv_frag_skb_fwd()
360 	packet = (struct batadv_frag_packet *)skb->data;  in batadv_frag_skb_fwd()
361 	orig_node_dst = batadv_orig_hash_find(bat_priv, packet->dest);  in batadv_frag_skb_fwd()
372 	total_size = ntohs(packet->total_size);  in batadv_frag_skb_fwd()
373 	if (total_size > neigh_node->if_incoming->net_dev->mtu) {  in batadv_frag_skb_fwd()
376 				   skb->len + ETH_HLEN);  in batadv_frag_skb_fwd()
378 		packet->ttl--;  in batadv_frag_skb_fwd()
390  * batadv_frag_create() - create a fragment from skb
408 	unsigned int tailroom = net_dev->needed_tailroom;  in batadv_frag_create()
417 	skb_fragment->priority = skb->priority;  in batadv_frag_create()
419 	/* Eat the last mtu-bytes of the skb */  in batadv_frag_create()
421 	skb_split(skb, skb_fragment, skb->len - fragment_size);  in batadv_frag_create()
425 	memcpy(skb_fragment->data, frag_head, header_size);  in batadv_frag_create()
432  * batadv_frag_send_packet() - create up to 16 fragments from the passed skb
435  * @neigh_node: next-hop of the created fragments
437  * Return: the netdev tx status or a negative errno code on a failure
443 	struct net_device *net_dev = neigh_node->if_incoming->net_dev;  in batadv_frag_send_packet()
448 	unsigned int mtu = net_dev->mtu;  in batadv_frag_send_packet()
453 	/* To avoid merge and refragmentation at next-hops we never send  in batadv_frag_send_packet()
457 	max_fragment_size = mtu - header_size;  in batadv_frag_send_packet()
459 	if (skb->len == 0 || max_fragment_size == 0)  in batadv_frag_send_packet()
460 		return -EINVAL;  in batadv_frag_send_packet()
462 	num_fragments = (skb->len - 1) / max_fragment_size + 1;  in batadv_frag_send_packet()
463 	max_fragment_size = (skb->len - 1) / num_fragments + 1;  in batadv_frag_send_packet()
467 		ret = -EAGAIN;  in batadv_frag_send_packet()
471 	bat_priv = orig_node->bat_priv;  in batadv_frag_send_packet()
474 		ret = -EINVAL;  in batadv_frag_send_packet()
481 	 * batman-adv fragments were created and submitted to the  in batadv_frag_send_packet()
482 	 * hard-interface  in batadv_frag_send_packet()
485 		ret = -ENOMEM;  in batadv_frag_send_packet()
493 	frag_header.seqno = htons(atomic_inc_return(&bat_priv->frag_seqno));  in batadv_frag_send_packet()
496 	frag_header.total_size = htons(skb->len);  in batadv_frag_send_packet()
498 	/* skb->priority values from 256->263 are magic values to  in batadv_frag_send_packet()
503 	if (skb->priority >= 256 && skb->priority <= 263)  in batadv_frag_send_packet()
504 		frag_header.priority = skb->priority - 256;  in batadv_frag_send_packet()
508 	ether_addr_copy(frag_header.orig, primary_if->net_dev->dev_addr);  in batadv_frag_send_packet()
509 	ether_addr_copy(frag_header.dest, orig_node->orig);  in batadv_frag_send_packet()
512 	while (skb->len > max_fragment_size) {  in batadv_frag_send_packet()
514 		if (unlikely(frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1)) {  in batadv_frag_send_packet()
515 			ret = -EINVAL;  in batadv_frag_send_packet()
522 			ret = -ENOMEM;  in batadv_frag_send_packet()
528 				   skb_fragment->len + ETH_HLEN);  in batadv_frag_send_packet()
546 	memcpy(skb->data, &frag_header, header_size);  in batadv_frag_send_packet()
551 			   skb->len + ETH_HLEN);  in batadv_frag_send_packet()