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8ea026b160
linux-next/net/batman-adv/main.h
Matthias Schiffer 8ea026b160 batman-adv: decrease maximum fragment size 
With this patch the maximum fragment size is reduced from 1400 to 1280
bytes.

Fragmentation v2 correctly uses the smaller of 1400 and the interface
MTU, thus generally supporting interfaces with an MTU < 1400 bytes, too.

However, currently "Fragmentation v2" does not support re-fragmentation.
Which means that once a packet is split into two packets of 1400 + x
bytes for instance and the next hop provides an interface with an even
smaller MTU of 1280 bytes, then the larger fragment is lost.

A maximum fragment size of 1280 bytes is a safer option as this is the
minimum MTU required by IPv6, making interfaces with an MTU < 1280
rather exotic.

Regarding performance, this should have no negative impact on unicast
traffic: Having some more bytes in the smaller and some less in the
larger does not change the sum of both fragments.

Concerning TT, choosing 1280 bytes fragments might result in more TT
messages than necessary when a large network is bridged into batman-adv.
However, the TT overhead in general is marginal due to its reactive
nature, therefore such a performance impact on TT should not be
noticeable for a user.

Cc: Matthias Schiffer <mschiffer@universe-factory.net>
[linus.luessing@c0d3.blue: Added commit message]
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2017-05-23 12:09:13 +02:00

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/* Copyright (C) 2007-2017 B.A.T.M.A.N. contributors:
*
* Marek Lindner, Simon Wunderlich
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _NET_BATMAN_ADV_MAIN_H_
#define _NET_BATMAN_ADV_MAIN_H_
#define BATADV_DRIVER_AUTHOR "Marek Lindner <mareklindner@neomailbox.ch>, " \
"Simon Wunderlich <sw@simonwunderlich.de>"
#define BATADV_DRIVER_DESC "B.A.T.M.A.N. advanced"
#define BATADV_DRIVER_DEVICE "batman-adv"
#ifndef BATADV_SOURCE_VERSION
#define BATADV_SOURCE_VERSION "2017.2"
#endif
/* B.A.T.M.A.N. parameters */
#define BATADV_TQ_MAX_VALUE 255
#define BATADV_THROUGHPUT_MAX_VALUE 0xFFFFFFFF
#define BATADV_JITTER 20
/* Time To Live of broadcast messages */
#define BATADV_TTL 50
/* maximum sequence number age of broadcast messages */
#define BATADV_BCAST_MAX_AGE 64
/* purge originators after time in seconds if no valid packet comes in
* -> TODO: check influence on BATADV_TQ_LOCAL_WINDOW_SIZE
*/
#define BATADV_PURGE_TIMEOUT 200000 /* 200 seconds */
#define BATADV_TT_LOCAL_TIMEOUT 600000 /* in milliseconds */
#define BATADV_TT_CLIENT_ROAM_TIMEOUT 600000 /* in milliseconds */
#define BATADV_TT_CLIENT_TEMP_TIMEOUT 600000 /* in milliseconds */
#define BATADV_TT_WORK_PERIOD 5000 /* 5 seconds */
#define BATADV_ORIG_WORK_PERIOD 1000 /* 1 second */
#define BATADV_MCAST_WORK_PERIOD 500 /* 0.5 seconds */
#define BATADV_DAT_ENTRY_TIMEOUT (5 * 60000) /* 5 mins in milliseconds */
/* sliding packet range of received originator messages in sequence numbers
* (should be a multiple of our word size)
*/
#define BATADV_TQ_LOCAL_WINDOW_SIZE 64
/* milliseconds we have to keep pending tt_req */
#define BATADV_TT_REQUEST_TIMEOUT 3000
#define BATADV_TQ_GLOBAL_WINDOW_SIZE 5
#define BATADV_TQ_LOCAL_BIDRECT_SEND_MINIMUM 1
#define BATADV_TQ_LOCAL_BIDRECT_RECV_MINIMUM 1
#define BATADV_TQ_TOTAL_BIDRECT_LIMIT 1
/* B.A.T.M.A.N. V */
#define BATADV_THROUGHPUT_DEFAULT_VALUE 10 /* 1 Mbps */
#define BATADV_ELP_PROBES_PER_NODE 2
#define BATADV_ELP_MIN_PROBE_SIZE 200 /* bytes */
#define BATADV_ELP_PROBE_MAX_TX_DIFF 100 /* milliseconds */
#define BATADV_ELP_MAX_AGE 64
#define BATADV_OGM_MAX_ORIGDIFF 5
#define BATADV_OGM_MAX_AGE 64
/* number of OGMs sent with the last tt diff */
#define BATADV_TT_OGM_APPEND_MAX 3
/* Time in which a client can roam at most ROAMING_MAX_COUNT times in
* milliseconds
*/
#define BATADV_ROAMING_MAX_TIME 20000
#define BATADV_ROAMING_MAX_COUNT 5
#define BATADV_NO_FLAGS 0
#define BATADV_NULL_IFINDEX 0 /* dummy ifindex used to avoid iface checks */
#define BATADV_NO_MARK 0
/* default interface for multi interface operation. The default interface is
* used for communication which originated locally (i.e. is not forwarded)
* or where special forwarding is not desired/necessary.
*/
#define BATADV_IF_DEFAULT ((struct batadv_hard_iface *)NULL)
#define BATADV_NUM_WORDS BITS_TO_LONGS(BATADV_TQ_LOCAL_WINDOW_SIZE)
#define BATADV_LOG_BUF_LEN 8192 /* has to be a power of 2 */
/* number of packets to send for broadcasts on different interface types */
#define BATADV_NUM_BCASTS_DEFAULT 1
#define BATADV_NUM_BCASTS_WIRELESS 3
#define BATADV_NUM_BCASTS_MAX 3
/* length of the single packet used by the TP meter */
#define BATADV_TP_PACKET_LEN ETH_DATA_LEN
/* msecs after which an ARP_REQUEST is sent in broadcast as fallback */
#define ARP_REQ_DELAY 250
/* numbers of originator to contact for any PUT/GET DHT operation */
#define BATADV_DAT_CANDIDATES_NUM 3
/* BATADV_TQ_SIMILARITY_THRESHOLD - TQ points that a secondary metric can differ
* at most from the primary one in order to be still considered acceptable
*/
#define BATADV_TQ_SIMILARITY_THRESHOLD 50
/* should not be bigger than 512 bytes or change the size of
* forw_packet->direct_link_flags
*/
#define BATADV_MAX_AGGREGATION_BYTES 512
#define BATADV_MAX_AGGREGATION_MS 100
#define BATADV_BLA_PERIOD_LENGTH 10000 /* 10 seconds */
#define BATADV_BLA_BACKBONE_TIMEOUT (BATADV_BLA_PERIOD_LENGTH * 6)
#define BATADV_BLA_CLAIM_TIMEOUT (BATADV_BLA_PERIOD_LENGTH * 10)
#define BATADV_BLA_WAIT_PERIODS 3
#define BATADV_BLA_LOOPDETECT_PERIODS 6
#define BATADV_BLA_LOOPDETECT_TIMEOUT 3000 /* 3 seconds */
#define BATADV_DUPLIST_SIZE 16
#define BATADV_DUPLIST_TIMEOUT 500 /* 500 ms */
/* don't reset again within 30 seconds */
#define BATADV_RESET_PROTECTION_MS 30000
#define BATADV_EXPECTED_SEQNO_RANGE 65536
#define BATADV_NC_NODE_TIMEOUT 10000 /* Milliseconds */
/**
* BATADV_TP_MAX_NUM - maximum number of simultaneously active tp sessions
*/
#define BATADV_TP_MAX_NUM 5
enum batadv_mesh_state {
BATADV_MESH_INACTIVE,
BATADV_MESH_ACTIVE,
BATADV_MESH_DEACTIVATING,
};
#define BATADV_BCAST_QUEUE_LEN 256
#define BATADV_BATMAN_QUEUE_LEN 256
enum batadv_uev_action {
BATADV_UEV_ADD = 0,
BATADV_UEV_DEL,
BATADV_UEV_CHANGE,
BATADV_UEV_LOOPDETECT,
};
enum batadv_uev_type {
BATADV_UEV_GW = 0,
BATADV_UEV_BLA,
};
#define BATADV_GW_THRESHOLD 50
/* Number of fragment chains for each orig_node */
#define BATADV_FRAG_BUFFER_COUNT 8
/* Maximum number of fragments for one packet */
#define BATADV_FRAG_MAX_FRAGMENTS 16
/* Maxumim size of each fragment */
#define BATADV_FRAG_MAX_FRAG_SIZE 1280
/* Time to keep fragments while waiting for rest of the fragments */
#define BATADV_FRAG_TIMEOUT 10000
#define BATADV_DAT_CANDIDATE_NOT_FOUND 0
#define BATADV_DAT_CANDIDATE_ORIG 1
/* Debug Messages */
#ifdef pr_fmt
#undef pr_fmt
#endif
/* Append 'batman-adv: ' before kernel messages */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
/* Kernel headers */
#include <linux/bitops.h> /* for packet.h */
#include <linux/compiler.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h> /* for packet.h */
#include <linux/if_vlan.h>
#include <linux/jiffies.h>
#include <linux/percpu.h>
#include <linux/types.h>
#include "packet.h"
#include "types.h"
struct net_device;
struct packet_type;
struct seq_file;
struct sk_buff;
/**
* batadv_print_vid - return printable version of vid information
* @vid: the VLAN identifier
*
* Return: -1 when no VLAN is used, VLAN id otherwise
*/
static inline int batadv_print_vid(unsigned short vid)
{
if (vid & BATADV_VLAN_HAS_TAG)
return (int)(vid & VLAN_VID_MASK);
else
return -1;
}
extern struct list_head batadv_hardif_list;
extern unsigned char batadv_broadcast_addr[];
extern struct workqueue_struct *batadv_event_workqueue;
int batadv_mesh_init(struct net_device *soft_iface);
void batadv_mesh_free(struct net_device *soft_iface);
bool batadv_is_my_mac(struct batadv_priv *bat_priv, const u8 *addr);
struct batadv_hard_iface *
batadv_seq_print_text_primary_if_get(struct seq_file *seq);
int batadv_max_header_len(void);
void batadv_skb_set_priority(struct sk_buff *skb, int offset);
int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *ptype,
struct net_device *orig_dev);
int
batadv_recv_handler_register(u8 packet_type,
int (*recv_handler)(struct sk_buff *,
struct batadv_hard_iface *));
void batadv_recv_handler_unregister(u8 packet_type);
__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr);
/**
* batadv_compare_eth - Compare two not u16 aligned Ethernet addresses
* @data1: Pointer to a six-byte array containing the Ethernet address
* @data2: Pointer other six-byte array containing the Ethernet address
*
* note: can't use ether_addr_equal() as it requires aligned memory
*
* Return: true if they are the same ethernet addr
*/
static inline bool batadv_compare_eth(const void *data1, const void *data2)
{
return ether_addr_equal_unaligned(data1, data2);
}
/**
* batadv_has_timed_out - compares current time (jiffies) and timestamp +
* timeout
* @timestamp: base value to compare with (in jiffies)
* @timeout: added to base value before comparing (in milliseconds)
*
* Return: true if current time is after timestamp + timeout
*/
static inline bool batadv_has_timed_out(unsigned long timestamp,
unsigned int timeout)
{
return time_is_before_jiffies(timestamp + msecs_to_jiffies(timeout));
}
#define batadv_atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
/* Returns the smallest signed integer in two's complement with the sizeof x */
#define batadv_smallest_signed_int(x) (1u << (7u + 8u * (sizeof(x) - 1u)))
/* Checks if a sequence number x is a predecessor/successor of y.
* they handle overflows/underflows and can correctly check for a
* predecessor/successor unless the variable sequence number has grown by
* more then 2**(bitwidth(x)-1)-1.
* This means that for a u8 with the maximum value 255, it would think:
* - when adding nothing - it is neither a predecessor nor a successor
* - before adding more than 127 to the starting value - it is a predecessor,
* - when adding 128 - it is neither a predecessor nor a successor,
* - after adding more than 127 to the starting value - it is a successor
*/
#define batadv_seq_before(x, y) ({typeof(x)_d1 = (x); \
typeof(y)_d2 = (y); \
typeof(x)_dummy = (_d1 - _d2); \
(void)(&_d1 == &_d2); \
_dummy > batadv_smallest_signed_int(_dummy); })
#define batadv_seq_after(x, y) batadv_seq_before(y, x)
/* Stop preemption on local cpu while incrementing the counter */
static inline void batadv_add_counter(struct batadv_priv *bat_priv, size_t idx,
size_t count)
{
this_cpu_add(bat_priv->bat_counters[idx], count);
}
#define batadv_inc_counter(b, i) batadv_add_counter(b, i, 1)
/* Define a macro to reach the control buffer of the skb. The members of the
* control buffer are defined in struct batadv_skb_cb in types.h.
* The macro is inspired by the similar macro TCP_SKB_CB() in tcp.h.
*/
#define BATADV_SKB_CB(__skb) ((struct batadv_skb_cb *)&((__skb)->cb[0]))
unsigned short batadv_get_vid(struct sk_buff *skb, size_t header_len);
bool batadv_vlan_ap_isola_get(struct batadv_priv *bat_priv, unsigned short vid);
#endif /* _NET_BATMAN_ADV_MAIN_H_ */
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