linux/net/batman-adv/packet.h
Sven Eckelmann ae361ce19f batman-adv: Calculate correct size for merged packets
The routing algorithm must be able to decide if a fragment can be merged with
the missing part and still be passed to a forwarding interface. The fragments
can only differ by one byte in case that the original payload had an uneven
length. In that situation the sender has to inform all possible receivers that
the tail is one byte longer using the flag UNI_FRAG_LARGETAIL.

The combination of UNI_FRAG_LARGETAIL and UNI_FRAG_HEAD flag makes it possible
to calculate the correct length for even and uneven sized payloads.

The original formula missed to add the unicast header at all and forgot to
remove the fragment header of the second fragment. This made the results highly
unreliable and only useful for machines with large differences between the
configured MTUs.

Reported-by: Russell Senior <russell@personaltelco.net>
Reported-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
2011-01-31 14:57:08 +01:00

137 lines
3.7 KiB
C

/*
* Copyright (C) 2007-2010 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*
*/
#ifndef _NET_BATMAN_ADV_PACKET_H_
#define _NET_BATMAN_ADV_PACKET_H_
#define ETH_P_BATMAN 0x4305 /* unofficial/not registered Ethertype */
#define BAT_PACKET 0x01
#define BAT_ICMP 0x02
#define BAT_UNICAST 0x03
#define BAT_BCAST 0x04
#define BAT_VIS 0x05
#define BAT_UNICAST_FRAG 0x06
/* this file is included by batctl which needs these defines */
#define COMPAT_VERSION 12
#define DIRECTLINK 0x40
#define VIS_SERVER 0x20
#define PRIMARIES_FIRST_HOP 0x10
/* ICMP message types */
#define ECHO_REPLY 0
#define DESTINATION_UNREACHABLE 3
#define ECHO_REQUEST 8
#define TTL_EXCEEDED 11
#define PARAMETER_PROBLEM 12
/* vis defines */
#define VIS_TYPE_SERVER_SYNC 0
#define VIS_TYPE_CLIENT_UPDATE 1
/* fragmentation defines */
#define UNI_FRAG_HEAD 0x01
#define UNI_FRAG_LARGETAIL 0x02
struct batman_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t flags; /* 0x40: DIRECTLINK flag, 0x20 VIS_SERVER flag... */
uint8_t tq;
uint32_t seqno;
uint8_t orig[6];
uint8_t prev_sender[6];
uint8_t ttl;
uint8_t num_hna;
uint8_t gw_flags; /* flags related to gateway class */
uint8_t align;
} __packed;
#define BAT_PACKET_LEN sizeof(struct batman_packet)
struct icmp_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t msg_type; /* see ICMP message types above */
uint8_t ttl;
uint8_t dst[6];
uint8_t orig[6];
uint16_t seqno;
uint8_t uid;
} __packed;
#define BAT_RR_LEN 16
/* icmp_packet_rr must start with all fields from imcp_packet
* as this is assumed by code that handles ICMP packets */
struct icmp_packet_rr {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t msg_type; /* see ICMP message types above */
uint8_t ttl;
uint8_t dst[6];
uint8_t orig[6];
uint16_t seqno;
uint8_t uid;
uint8_t rr_cur;
uint8_t rr[BAT_RR_LEN][ETH_ALEN];
} __packed;
struct unicast_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t dest[6];
uint8_t ttl;
} __packed;
struct unicast_frag_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t dest[6];
uint8_t ttl;
uint8_t flags;
uint8_t orig[6];
uint16_t seqno;
} __packed;
struct bcast_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t orig[6];
uint8_t ttl;
uint32_t seqno;
} __packed;
struct vis_packet {
uint8_t packet_type;
uint8_t version; /* batman version field */
uint8_t vis_type; /* which type of vis-participant sent this? */
uint8_t entries; /* number of entries behind this struct */
uint32_t seqno; /* sequence number */
uint8_t ttl; /* TTL */
uint8_t vis_orig[6]; /* originator that informs about its
* neighbors */
uint8_t target_orig[6]; /* who should receive this packet */
uint8_t sender_orig[6]; /* who sent or rebroadcasted this packet */
} __packed;
#endif /* _NET_BATMAN_ADV_PACKET_H_ */