![Simon Wunderlich](/assets/img/avatar_default.png)
This patch limits the queue lengths of batman and broadcast packets. BATMAN packets are held back for aggregation and jittered to avoid interferences. Broadcast packets are stored to be sent out multiple times to increase the probability to be received by other nodes in lossy environments. Especially in extreme cases like broadcast storms, the queues have been seen to run full, eating up all the memory and triggering the infamous OOM killer. With the queue length limits introduced in this patch, this problem is avoided. Each queue is limited to 256 entries for now, resulting in 1 MB of maximum space available in total for typical setups (assuming one packet including overhead does not require more than 2000 byte). This should also be reasonable for smaller routers, otherwise the defines can be tweaked later. This third version of the patch does not increase the local broadcast sequence number when the queue is already full. Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de> Signed-off-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
269 lines
8.1 KiB
C
269 lines
8.1 KiB
C
/*
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* Copyright (C) 2007-2010 B.A.T.M.A.N. contributors:
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*
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* Marek Lindner, Simon Wunderlich
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*
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*/
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#include "main.h"
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#include "aggregation.h"
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#include "send.h"
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#include "routing.h"
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/* calculate the size of the hna information for a given packet */
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static int hna_len(struct batman_packet *batman_packet)
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{
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return batman_packet->num_hna * ETH_ALEN;
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}
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/* return true if new_packet can be aggregated with forw_packet */
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static bool can_aggregate_with(struct batman_packet *new_batman_packet,
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int packet_len,
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unsigned long send_time,
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bool directlink,
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struct batman_if *if_incoming,
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struct forw_packet *forw_packet)
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{
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struct batman_packet *batman_packet =
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(struct batman_packet *)forw_packet->packet_buff;
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int aggregated_bytes = forw_packet->packet_len + packet_len;
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/**
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* we can aggregate the current packet to this aggregated packet
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* if:
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*
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* - the send time is within our MAX_AGGREGATION_MS time
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* - the resulting packet wont be bigger than
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* MAX_AGGREGATION_BYTES
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*/
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if (time_before(send_time, forw_packet->send_time) &&
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time_after_eq(send_time + msecs_to_jiffies(MAX_AGGREGATION_MS),
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forw_packet->send_time) &&
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(aggregated_bytes <= MAX_AGGREGATION_BYTES)) {
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/**
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* check aggregation compatibility
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* -> direct link packets are broadcasted on
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* their interface only
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* -> aggregate packet if the current packet is
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* a "global" packet as well as the base
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* packet
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*/
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/* packets without direct link flag and high TTL
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* are flooded through the net */
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if ((!directlink) &&
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(!(batman_packet->flags & DIRECTLINK)) &&
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(batman_packet->ttl != 1) &&
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/* own packets originating non-primary
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* interfaces leave only that interface */
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((!forw_packet->own) ||
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(forw_packet->if_incoming->if_num == 0)))
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return true;
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/* if the incoming packet is sent via this one
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* interface only - we still can aggregate */
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if ((directlink) &&
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(new_batman_packet->ttl == 1) &&
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(forw_packet->if_incoming == if_incoming) &&
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/* packets from direct neighbors or
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* own secondary interface packets
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* (= secondary interface packets in general) */
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(batman_packet->flags & DIRECTLINK ||
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(forw_packet->own &&
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forw_packet->if_incoming->if_num != 0)))
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return true;
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}
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return false;
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}
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#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
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/* create a new aggregated packet and add this packet to it */
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static void new_aggregated_packet(unsigned char *packet_buff,
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int packet_len,
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unsigned long send_time,
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bool direct_link,
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struct batman_if *if_incoming,
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int own_packet)
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{
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struct forw_packet *forw_packet_aggr;
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unsigned long flags;
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/* own packet should always be scheduled */
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if (!own_packet) {
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if (!atomic_dec_not_zero(&batman_queue_left)) {
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bat_dbg(DBG_BATMAN, "batman packet queue full\n");
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return;
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}
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}
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forw_packet_aggr = kmalloc(sizeof(struct forw_packet), GFP_ATOMIC);
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if (!forw_packet_aggr) {
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if (!own_packet)
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atomic_inc(&batman_queue_left);
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return;
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}
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forw_packet_aggr->packet_buff = kmalloc(MAX_AGGREGATION_BYTES,
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GFP_ATOMIC);
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if (!forw_packet_aggr->packet_buff) {
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if (!own_packet)
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atomic_inc(&batman_queue_left);
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kfree(forw_packet_aggr);
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return;
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}
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INIT_HLIST_NODE(&forw_packet_aggr->list);
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forw_packet_aggr->packet_len = packet_len;
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memcpy(forw_packet_aggr->packet_buff,
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packet_buff,
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forw_packet_aggr->packet_len);
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forw_packet_aggr->skb = NULL;
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forw_packet_aggr->own = own_packet;
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forw_packet_aggr->if_incoming = if_incoming;
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forw_packet_aggr->num_packets = 0;
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forw_packet_aggr->direct_link_flags = 0;
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forw_packet_aggr->send_time = send_time;
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/* save packet direct link flag status */
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if (direct_link)
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forw_packet_aggr->direct_link_flags |= 1;
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/* add new packet to packet list */
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spin_lock_irqsave(&forw_bat_list_lock, flags);
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hlist_add_head(&forw_packet_aggr->list, &forw_bat_list);
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spin_unlock_irqrestore(&forw_bat_list_lock, flags);
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/* start timer for this packet */
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INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
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send_outstanding_bat_packet);
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queue_delayed_work(bat_event_workqueue,
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&forw_packet_aggr->delayed_work,
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send_time - jiffies);
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}
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/* aggregate a new packet into the existing aggregation */
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static void aggregate(struct forw_packet *forw_packet_aggr,
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unsigned char *packet_buff,
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int packet_len,
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bool direct_link)
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{
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memcpy((forw_packet_aggr->packet_buff + forw_packet_aggr->packet_len),
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packet_buff, packet_len);
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forw_packet_aggr->packet_len += packet_len;
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forw_packet_aggr->num_packets++;
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/* save packet direct link flag status */
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if (direct_link)
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forw_packet_aggr->direct_link_flags |=
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(1 << forw_packet_aggr->num_packets);
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}
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void add_bat_packet_to_list(struct bat_priv *bat_priv,
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unsigned char *packet_buff, int packet_len,
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struct batman_if *if_incoming, char own_packet,
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unsigned long send_time)
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{
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/**
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* _aggr -> pointer to the packet we want to aggregate with
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* _pos -> pointer to the position in the queue
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*/
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struct forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
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struct hlist_node *tmp_node;
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struct batman_packet *batman_packet =
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(struct batman_packet *)packet_buff;
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bool direct_link = batman_packet->flags & DIRECTLINK ? 1 : 0;
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unsigned long flags;
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/* find position for the packet in the forward queue */
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spin_lock_irqsave(&forw_bat_list_lock, flags);
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/* own packets are not to be aggregated */
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if ((atomic_read(&bat_priv->aggregation_enabled)) && (!own_packet)) {
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hlist_for_each_entry(forw_packet_pos, tmp_node, &forw_bat_list,
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list) {
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if (can_aggregate_with(batman_packet,
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packet_len,
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send_time,
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direct_link,
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if_incoming,
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forw_packet_pos)) {
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forw_packet_aggr = forw_packet_pos;
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break;
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}
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}
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}
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/* nothing to aggregate with - either aggregation disabled or no
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* suitable aggregation packet found */
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if (forw_packet_aggr == NULL) {
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/* the following section can run without the lock */
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spin_unlock_irqrestore(&forw_bat_list_lock, flags);
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/**
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* if we could not aggregate this packet with one of the others
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* we hold it back for a while, so that it might be aggregated
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* later on
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*/
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if ((!own_packet) &&
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(atomic_read(&bat_priv->aggregation_enabled)))
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send_time += msecs_to_jiffies(MAX_AGGREGATION_MS);
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new_aggregated_packet(packet_buff, packet_len,
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send_time, direct_link,
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if_incoming, own_packet);
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} else {
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aggregate(forw_packet_aggr,
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packet_buff, packet_len,
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direct_link);
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spin_unlock_irqrestore(&forw_bat_list_lock, flags);
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}
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}
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/* unpack the aggregated packets and process them one by one */
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void receive_aggr_bat_packet(struct ethhdr *ethhdr, unsigned char *packet_buff,
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int packet_len, struct batman_if *if_incoming)
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{
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struct batman_packet *batman_packet;
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int buff_pos = 0;
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unsigned char *hna_buff;
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batman_packet = (struct batman_packet *)packet_buff;
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while (aggregated_packet(buff_pos, packet_len,
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batman_packet->num_hna)) {
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/* network to host order for our 16bit seqno, and the
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orig_interval. */
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batman_packet->seqno = ntohs(batman_packet->seqno);
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hna_buff = packet_buff + buff_pos + BAT_PACKET_LEN;
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receive_bat_packet(ethhdr, batman_packet,
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hna_buff, hna_len(batman_packet),
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if_incoming);
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buff_pos += BAT_PACKET_LEN + hna_len(batman_packet);
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batman_packet = (struct batman_packet *)
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(packet_buff + buff_pos);
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}
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}
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