Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /* Copyright (C) 2013-2020  B.A.T.M.A.N. contributors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * Martin Hundebøll <martin@hundeboll.net>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include "fragmentation.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include "main.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/atomic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/byteorder/generic.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/etherdevice.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/gfp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/if_ether.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/jiffies.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/lockdep.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/netdevice.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/skbuff.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <uapi/linux/batadv_packet.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include "hard-interface.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include "originator.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include "routing.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include "send.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #include "soft-interface.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  * batadv_frag_clear_chain() - delete entries in the fragment buffer chain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  * @head: head of chain with entries.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  * @dropped: whether the chain is cleared because all fragments are dropped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  * Free fragments in the passed hlist. Should be called with appropriate lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) static void batadv_frag_clear_chain(struct hlist_head *head, bool dropped)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	struct batadv_frag_list_entry *entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	struct hlist_node *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	hlist_for_each_entry_safe(entry, node, head, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		hlist_del(&entry->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		if (dropped)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 			kfree_skb(entry->skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 			consume_skb(entry->skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		kfree(entry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57)  * batadv_frag_purge_orig() - free fragments associated to an orig
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58)  * @orig_node: originator to free fragments from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59)  * @check_cb: optional function to tell if an entry should be purged
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) void batadv_frag_purge_orig(struct batadv_orig_node *orig_node,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 			    bool (*check_cb)(struct batadv_frag_table_entry *))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	struct batadv_frag_table_entry *chain;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	u8 i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	for (i = 0; i < BATADV_FRAG_BUFFER_COUNT; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		chain = &orig_node->fragments[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		spin_lock_bh(&chain->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 		if (!check_cb || check_cb(chain)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 			batadv_frag_clear_chain(&chain->fragment_list, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 			chain->size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		spin_unlock_bh(&chain->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81)  * batadv_frag_size_limit() - maximum possible size of packet to be fragmented
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83)  * Return: the maximum size of payload that can be fragmented.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) static int batadv_frag_size_limit(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	int limit = BATADV_FRAG_MAX_FRAG_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	limit -= sizeof(struct batadv_frag_packet);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	limit *= BATADV_FRAG_MAX_FRAGMENTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	return limit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96)  * batadv_frag_init_chain() - check and prepare fragment chain for new fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97)  * @chain: chain in fragments table to init
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98)  * @seqno: sequence number of the received fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)  * Make chain ready for a fragment with sequence number "seqno". Delete existing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)  * entries if they have an "old" sequence number.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  * Caller must hold chain->lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)  * Return: true if chain is empty and the caller can just insert the new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)  * fragment without searching for the right position.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 				   u16 seqno)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	lockdep_assert_held(&chain->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	if (chain->seqno == seqno)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	if (!hlist_empty(&chain->fragment_list))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		batadv_frag_clear_chain(&chain->fragment_list, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	chain->size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	chain->seqno = seqno;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126)  * batadv_frag_insert_packet() - insert a fragment into a fragment chain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)  * @orig_node: originator that the fragment was received from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)  * @skb: skb to insert
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  * @chain_out: list head to attach complete chains of fragments to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  * Insert a new fragment into the reverse ordered chain in the right table
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  * entry. The hash table entry is cleared if "old" fragments exist in it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)  * Return: true if skb is buffered, false on error. If the chain has all the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)  * fragments needed to merge the packet, the chain is moved to the passed head
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)  * to avoid locking the chain in the table.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 				      struct sk_buff *skb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 				      struct hlist_head *chain_out)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	struct batadv_frag_table_entry *chain;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	struct batadv_frag_list_entry *frag_entry_new = NULL, *frag_entry_curr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	struct batadv_frag_list_entry *frag_entry_last = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	struct batadv_frag_packet *frag_packet;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	u8 bucket;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	u16 seqno, hdr_size = sizeof(struct batadv_frag_packet);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	bool ret = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	/* Linearize packet to avoid linearizing 16 packets in a row when doing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	 * the later merge. Non-linear merge should be added to remove this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	 * linearization.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	if (skb_linearize(skb) < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		goto err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	frag_packet = (struct batadv_frag_packet *)skb->data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	seqno = ntohs(frag_packet->seqno);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	bucket = seqno % BATADV_FRAG_BUFFER_COUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	frag_entry_new = kmalloc(sizeof(*frag_entry_new), GFP_ATOMIC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	if (!frag_entry_new)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		goto err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	frag_entry_new->skb = skb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	frag_entry_new->no = frag_packet->no;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	/* Select entry in the "chain table" and delete any prior fragments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	 * with another sequence number. batadv_frag_init_chain() returns true,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	 * if the list is empty at return.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	chain = &orig_node->fragments[bucket];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	spin_lock_bh(&chain->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	if (batadv_frag_init_chain(chain, seqno)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 		hlist_add_head(&frag_entry_new->list, &chain->fragment_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 		chain->size = skb->len - hdr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		chain->timestamp = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		chain->total_size = ntohs(frag_packet->total_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	/* Find the position for the new fragment. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	hlist_for_each_entry(frag_entry_curr, &chain->fragment_list, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		/* Drop packet if fragment already exists. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 		if (frag_entry_curr->no == frag_entry_new->no)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		/* Order fragments from highest to lowest. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		if (frag_entry_curr->no < frag_entry_new->no) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			hlist_add_before(&frag_entry_new->list,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 					 &frag_entry_curr->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 			chain->size += skb->len - hdr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 			chain->timestamp = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 			ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		/* store current entry because it could be the last in list */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		frag_entry_last = frag_entry_curr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	/* Reached the end of the list, so insert after 'frag_entry_last'. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	if (likely(frag_entry_last)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		hlist_add_behind(&frag_entry_new->list, &frag_entry_last->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		chain->size += skb->len - hdr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		chain->timestamp = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 		ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	if (chain->size > batadv_frag_size_limit() ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	    chain->total_size != ntohs(frag_packet->total_size) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	    chain->total_size > batadv_frag_size_limit()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		/* Clear chain if total size of either the list or the packet
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		 * exceeds the maximum size of one merged packet. Don't allow
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 		 * packets to have different total_size.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 		batadv_frag_clear_chain(&chain->fragment_list, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 		chain->size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	} else if (ntohs(frag_packet->total_size) == chain->size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 		/* All fragments received. Hand over chain to caller. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 		hlist_move_list(&chain->fragment_list, chain_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		chain->size = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) err_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	spin_unlock_bh(&chain->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	if (!ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 		kfree(frag_entry_new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 		kfree_skb(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)  * batadv_frag_merge_packets() - merge a chain of fragments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)  * @chain: head of chain with fragments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243)  * Expand the first skb in the chain and copy the content of the remaining
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244)  * skb's into the expanded one. After doing so, clear the chain.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)  * Return: the merged skb or NULL on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) static struct sk_buff *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) batadv_frag_merge_packets(struct hlist_head *chain)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	struct batadv_frag_packet *packet;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	struct batadv_frag_list_entry *entry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	struct sk_buff *skb_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	int size, hdr_size = sizeof(struct batadv_frag_packet);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	bool dropped = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	/* Remove first entry, as this is the destination for the rest of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	 * fragments.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	entry = hlist_entry(chain->first, struct batadv_frag_list_entry, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	hlist_del(&entry->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	skb_out = entry->skb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	kfree(entry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	packet = (struct batadv_frag_packet *)skb_out->data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	size = ntohs(packet->total_size) + hdr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	/* Make room for the rest of the fragments. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	if (pskb_expand_head(skb_out, 0, size - skb_out->len, GFP_ATOMIC) < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		kfree_skb(skb_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		skb_out = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		dropped = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 		goto free;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	/* Move the existing MAC header to just before the payload. (Override
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	 * the fragment header.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	skb_pull(skb_out, hdr_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 	skb_out->ip_summed = CHECKSUM_NONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	memmove(skb_out->data - ETH_HLEN, skb_mac_header(skb_out), ETH_HLEN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	skb_set_mac_header(skb_out, -ETH_HLEN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	skb_reset_network_header(skb_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	skb_reset_transport_header(skb_out);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	/* Copy the payload of the each fragment into the last skb */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	hlist_for_each_entry(entry, chain, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 		size = entry->skb->len - hdr_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		skb_put_data(skb_out, entry->skb->data + hdr_size, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) free:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 	/* Locking is not needed, because 'chain' is not part of any orig. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	batadv_frag_clear_chain(chain, dropped);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	return skb_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299)  * batadv_frag_skb_buffer() - buffer fragment for later merge
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300)  * @skb: skb to buffer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301)  * @orig_node_src: originator that the skb is received from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303)  * Add fragment to buffer and merge fragments if possible.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305)  * There are three possible outcomes: 1) Packet is merged: Return true and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306)  * set *skb to merged packet; 2) Packet is buffered: Return true and set *skb
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307)  * to NULL; 3) Error: Return false and free skb.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309)  * Return: true when the packet is merged or buffered, false when skb is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310)  * used.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) bool batadv_frag_skb_buffer(struct sk_buff **skb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 			    struct batadv_orig_node *orig_node_src)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	struct sk_buff *skb_out = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	struct hlist_head head = HLIST_HEAD_INIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	bool ret = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	/* Add packet to buffer and table entry if merge is possible. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	if (!batadv_frag_insert_packet(orig_node_src, *skb, &head))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	/* Leave if more fragments are needed to merge. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 	if (hlist_empty(&head))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	skb_out = batadv_frag_merge_packets(&head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	if (!skb_out)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	*skb = skb_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)  * batadv_frag_skb_fwd() - forward fragments that would exceed MTU when merged
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340)  * @skb: skb to forward
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341)  * @recv_if: interface that the skb is received on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342)  * @orig_node_src: originator that the skb is received from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344)  * Look up the next-hop of the fragments payload and check if the merged packet
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345)  * will exceed the MTU towards the next-hop. If so, the fragment is forwarded
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346)  * without merging it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348)  * Return: true if the fragment is consumed/forwarded, false otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) bool batadv_frag_skb_fwd(struct sk_buff *skb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 			 struct batadv_hard_iface *recv_if,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 			 struct batadv_orig_node *orig_node_src)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 	struct batadv_orig_node *orig_node_dst;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	struct batadv_neigh_node *neigh_node = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 	struct batadv_frag_packet *packet;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	u16 total_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	bool ret = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 	packet = (struct batadv_frag_packet *)skb->data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 	orig_node_dst = batadv_orig_hash_find(bat_priv, packet->dest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 	if (!orig_node_dst)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 	neigh_node = batadv_find_router(bat_priv, orig_node_dst, recv_if);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 	if (!neigh_node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 	/* Forward the fragment, if the merged packet would be too big to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 	 * be assembled.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 	total_size = ntohs(packet->total_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 	if (total_size > neigh_node->if_incoming->net_dev->mtu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 		batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_FWD);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 		batadv_add_counter(bat_priv, BATADV_CNT_FRAG_FWD_BYTES,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 				   skb->len + ETH_HLEN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 		packet->ttl--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) 		batadv_send_unicast_skb(skb, neigh_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) 		ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 	if (orig_node_dst)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 		batadv_orig_node_put(orig_node_dst);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 	if (neigh_node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 		batadv_neigh_node_put(neigh_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393)  * batadv_frag_create() - create a fragment from skb
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394)  * @net_dev: outgoing device for fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395)  * @skb: skb to create fragment from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396)  * @frag_head: header to use in new fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397)  * @fragment_size: size of new fragment
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399)  * Split the passed skb into two fragments: A new one with size matching the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400)  * passed mtu and the old one with the rest. The new skb contains data from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401)  * tail of the old skb.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403)  * Return: the new fragment, NULL on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) static struct sk_buff *batadv_frag_create(struct net_device *net_dev,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) 					  struct sk_buff *skb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) 					  struct batadv_frag_packet *frag_head,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) 					  unsigned int fragment_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) 	unsigned int ll_reserved = LL_RESERVED_SPACE(net_dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) 	unsigned int tailroom = net_dev->needed_tailroom;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) 	struct sk_buff *skb_fragment;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) 	unsigned int header_size = sizeof(*frag_head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) 	unsigned int mtu = fragment_size + header_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) 	skb_fragment = dev_alloc_skb(ll_reserved + mtu + tailroom);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) 	if (!skb_fragment)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) 		goto err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) 	skb_fragment->priority = skb->priority;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) 	/* Eat the last mtu-bytes of the skb */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) 	skb_reserve(skb_fragment, ll_reserved + header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) 	skb_split(skb, skb_fragment, skb->len - fragment_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) 	/* Add the header */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) 	skb_push(skb_fragment, header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) 	memcpy(skb_fragment->data, frag_head, header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) 	return skb_fragment;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435)  * batadv_frag_send_packet() - create up to 16 fragments from the passed skb
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436)  * @skb: skb to create fragments from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437)  * @orig_node: final destination of the created fragments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438)  * @neigh_node: next-hop of the created fragments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440)  * Return: the netdev tx status or a negative errno code on a failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) int batadv_frag_send_packet(struct sk_buff *skb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) 			    struct batadv_orig_node *orig_node,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) 			    struct batadv_neigh_node *neigh_node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) 	struct net_device *net_dev = neigh_node->if_incoming->net_dev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) 	struct batadv_priv *bat_priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) 	struct batadv_hard_iface *primary_if = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) 	struct batadv_frag_packet frag_header;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) 	struct sk_buff *skb_fragment;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) 	unsigned int mtu = net_dev->mtu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) 	unsigned int header_size = sizeof(frag_header);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) 	unsigned int max_fragment_size, num_fragments;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) 	/* To avoid merge and refragmentation at next-hops we never send
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) 	 * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) 	mtu = min_t(unsigned int, mtu, BATADV_FRAG_MAX_FRAG_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) 	max_fragment_size = mtu - header_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) 	if (skb->len == 0 || max_fragment_size == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) 	num_fragments = (skb->len - 1) / max_fragment_size + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) 	max_fragment_size = (skb->len - 1) / num_fragments + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) 	/* Don't even try to fragment, if we need more than 16 fragments */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) 	if (num_fragments > BATADV_FRAG_MAX_FRAGMENTS) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) 		ret = -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) 		goto free_skb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) 	bat_priv = orig_node->bat_priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) 	primary_if = batadv_primary_if_get_selected(bat_priv);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476) 	if (!primary_if) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) 		ret = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) 		goto free_skb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481) 	/* Create one header to be copied to all fragments */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) 	frag_header.packet_type = BATADV_UNICAST_FRAG;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483) 	frag_header.version = BATADV_COMPAT_VERSION;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) 	frag_header.ttl = BATADV_TTL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) 	frag_header.seqno = htons(atomic_inc_return(&bat_priv->frag_seqno));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486) 	frag_header.reserved = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) 	frag_header.no = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) 	frag_header.total_size = htons(skb->len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) 	/* skb->priority values from 256->263 are magic values to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) 	 * directly indicate a specific 802.1d priority.  This is used
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) 	 * to allow 802.1d priority to be passed directly in from VLAN
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493) 	 * tags, etc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495) 	if (skb->priority >= 256 && skb->priority <= 263)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) 		frag_header.priority = skb->priority - 256;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) 		frag_header.priority = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500) 	ether_addr_copy(frag_header.orig, primary_if->net_dev->dev_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) 	ether_addr_copy(frag_header.dest, orig_node->orig);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) 	/* Eat and send fragments from the tail of skb */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) 	while (skb->len > max_fragment_size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) 		/* The initial check in this function should cover this case */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506) 		if (unlikely(frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) 			ret = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) 			goto put_primary_if;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) 		skb_fragment = batadv_frag_create(net_dev, skb, &frag_header,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) 						  max_fragment_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513) 		if (!skb_fragment) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) 			ret = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) 			goto put_primary_if;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518) 		batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) 		batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) 				   skb_fragment->len + ETH_HLEN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) 		ret = batadv_send_unicast_skb(skb_fragment, neigh_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) 		if (ret != NET_XMIT_SUCCESS) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) 			ret = NET_XMIT_DROP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) 			goto put_primary_if;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527) 		frag_header.no++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) 	/* make sure that there is at least enough head for the fragmentation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) 	 * and ethernet headers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) 	ret = skb_cow_head(skb, ETH_HLEN + header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) 		goto put_primary_if;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) 	skb_push(skb, header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538) 	memcpy(skb->data, &frag_header, header_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) 	/* Send the last fragment */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) 	batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) 	batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) 			   skb->len + ETH_HLEN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) 	ret = batadv_send_unicast_skb(skb, neigh_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) 	/* skb was consumed */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) 	skb = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) put_primary_if:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549) 	batadv_hardif_put(primary_if);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550) free_skb:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) 	kfree_skb(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554) }