packet.h File Reference

Function prototypes for packet.c, EAPOL/EAP data structures. More...

#include <stdlib.h>
#include <linux/types.h>
#include "parser.h"

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Go to the source code of this file.

Data Structures
struct	packet_auxdata_t
	A redefinition of struct tpacket_auxdata from <linux/if_packet.h>. More...
struct	eapol_eap
	EAPOL-EAP (EAP Packet) format. More...
struct	eapol_key
	EAPOL-Key (Key Descriptor) format. More...
struct	eapol_mpdu
	EAPOL MAC Protocol Data Unit (MPDU) format. More...
struct	peapod_packet
	Represents an EAPOL packet with some metadata already extracted. More...
struct	decode_t
	Matches a single-byte value with a description. More...

Macros
EAPOL Packet Types
See also IEEE Std 802.1X-2010 §11.3.2
#define	EAPOL_EAP   0
#define	EAPOL_START   1
#define	EAPOL_LOGOFF   2
#define	EAPOL_KEY   3
#define	EAPOL_ENCAPSULATED_ASF_ALERT   4
#define	EAPOL_MKA   5
#define	EAPOL_ANNOUNCEMENT_GENERIC   6
#define	EAPOL_ANNOUNCEMENT_SPECIFIC   7
#define	EAPOL_ANNOUNCEMENT_REQ   8
EAP Code
Note RFC 2284 has been superseded by RFC 3748 and its successors, but the numeric Code values can only be found in the former. See also RFC 2284 §2.2
#define	EAP_CODE_REQUEST   1
#define	EAP_CODE_RESPONSE   2
#define	EAP_CODE_SUCCESS   3
#define	EAP_CODE_FAILURE   4
EAP-Request/Response Type
These apply if the EAP packet has Code of either Request or Response. See also RFC 3748 §5 for the initial Types (1-6, 254-255)
#define	EAP_TYPE_IDENTITY   1
#define	EAP_TYPE_NOTIFICATION   2
#define	EAP_TYPE_NAK   3
#define	EAP_TYPE_MD5_CHALLENGE   4
#define	EAP_TYPE_OTP   5
#define	EAP_TYPE_GTC   6
#define	EAP_TYPE_TLS   13
#define	EAP_TYPE_SIM   18
#define	EAP_TYPE_TTLS   21
#define	EAP_TYPE_AKA_OLD   23
#define	EAP_TYPE_PEAP   25
#define	EAP_TYPE_MS_CHAP_V2   26
#define	EAP_TYPE_MS_CHAP_V2_OLD   29
#define	EAP_TYPE_FAST   43
#define	EAP_TYPE_IKEV2   49
#define	EAP_TYPE_EXPANDED_TYPES   254
#define	EAP_TYPE_EXPERIMENTAL_USE   255
EAPOL-Key Descriptor Type
See also IEEE Std 802.1X-2010 §11.9
#define	EAPOL_KEY_TYPE_RC4   1
#define	EAPOL_KEY_TYPE_IEEE_80211   2

Functions
void	packet_init (struct iface_t *ifaces)
	Allocate the main buffer for the EAPOL packet. More...
uint8_t *	packet_buf (struct peapod_packet packet, uint8_t orig)
	Return a pointer to a raw EAPOL packet. More...
char *	packet_decode (uint8_t val, const struct decode_t *decode)
	Decode a byte in an EAPOL packet to a C string. More...
uint32_t	packet_tcitonl (struct tci_t tci)
	Convert a struct tci_t to a 4-byte 802.1Q tag. More...
int	packet_send (struct peapod_packet packet, struct iface_t *iface)
	Send an EAPOL packet on a network interface. More...
struct peapod_packet	packet_recvmsg (struct iface_t *iface)
	Receive an EAPOL packet on a network interface. More...

Variables
static const struct decode_t	eapol_types []
	EAPOL Packet Type descriptions. More...
static const struct decode_t	eap_codes []
	EAP Code descriptions. More...
static const struct decode_t	eap_types []
	EAP-Request/Response Type descriptions. More...
static const struct decode_t	eapol_key_types []
	Descriptions for EAPOL-Key Descriptor Type. More...

Detailed Description

Function prototypes for packet.c, EAPOL/EAP data structures.

Macro Definition Documentation

#define EAPOL_EAP   0

#define EAPOL_START   1

#define EAPOL_LOGOFF   2

#define EAPOL_KEY   3

#define EAPOL_ENCAPSULATED_ASF_ALERT   4

#define EAPOL_MKA   5

#define EAPOL_ANNOUNCEMENT_GENERIC   6

#define EAPOL_ANNOUNCEMENT_SPECIFIC   7

#define EAPOL_ANNOUNCEMENT_REQ   8

#define EAP_CODE_REQUEST   1

#define EAP_CODE_RESPONSE   2

#define EAP_CODE_SUCCESS   3

#define EAP_CODE_FAILURE   4

#define EAP_TYPE_IDENTITY   1

#define EAP_TYPE_NOTIFICATION   2

#define EAP_TYPE_NAK   3

#define EAP_TYPE_MD5_CHALLENGE   4

#define EAP_TYPE_OTP   5

#define EAP_TYPE_GTC   6

#define EAP_TYPE_TLS   13

See also

RFC 2716 §4.1

#define EAP_TYPE_SIM   18

See also

RFC 4186 §8.1

#define EAP_TYPE_TTLS   21

See also

RFC 5281 §9.1

#define EAP_TYPE_AKA_OLD   23

See also

RFC 4187 §8.1

#define EAP_TYPE_PEAP   25

See also

draft-josefsson-pppext-eap-tls-eap-06.txt §3.1

#define EAP_TYPE_MS_CHAP_V2   26

See also

draft-kamath-pppext-eap-mschapv2-02.txt §2

#define EAP_TYPE_MS_CHAP_V2_OLD   29

See also

draft-dpotter-pppext-eap-mschap-01.txt §4.1

#define EAP_TYPE_FAST   43

See also

RFC 4851 §4.1

#define EAP_TYPE_IKEV2   49

See also

RFC 5106 §8

#define EAP_TYPE_EXPANDED_TYPES   254

#define EAP_TYPE_EXPERIMENTAL_USE   255

#define EAPOL_KEY_TYPE_RC4   1

Note

Deprecated

#define EAPOL_KEY_TYPE_IEEE_80211   2

See also

IEEE Std 802.11

Function Documentation

void packet_init

(

struct iface_t *

ifaces

)

Allocate the main buffer for the EAPOL packet.

The size of the buffer is determined according to the highest MTU of the network interfaces used by the program.

Parameters

ifaces

Pointer to a list of struct iface_t structures representing network interfaces

Note

valgrind claims the memory allocated here is "possibly lost". Ignore it; we're "doing unusual things with pointers that could cause them to point into the middle of an allocated block". Quite deliberately so.

See also

http://valgrind.org/docs/manual/faq.html#faq.deflost

uint8_t* packet_buf	(	struct peapod_packet	packet,
		uint8_t	orig
	)

Return a pointer to a raw EAPOL packet.

Rewrites the first 16 bytes of the main packet buffer. The result shall point to the beginning of a raw EAPOL packet that is either:

1. the original packet, including the VLAN tag, as it appeared when it was captured on the ingress interface, or
2. the processed packet, possibly with original VLAN tag removed or tag fields changed according to interface egress options, that should be sent out on a given egress interface.

The result may then be used by the caller to (hex)dump, Base64-encode, and/or send the packet.

Parameters

packet	A struct peapod_packet representing an EAPOL packet
orig	Flag: Reconstruct original packet as seen on ingress interface?

Returns

Pointer to the beginning of a complete EAPOL packet

char* packet_decode	(	uint8_t	val,
		const struct decode_t *	decode
	)

Decode a byte in an EAPOL packet to a C string.

The byte may be one of the following:

1. the Type field of an EAPOL packet,
2. the Code field of an EAP packet encapsulated in an EAPOL-EAP packet, or
3. the Type field of an EAP-Request or EAP-Response encapsulated in an EAP packet.

Parameters

val	Value of the relevant byte to decode
decode	Pointer to a struct decode_t matching field values with descriptions

Returns

A description, or "Unknown" if the value does not have a corresponding description in decode.

uint32_t packet_tcitonl

(

struct tci_t

tci

)

Convert a struct tci_t to a 4-byte 802.1Q tag.

Parameters

tci	A struct tci_t representing an 802.1Q TCI

Returns

An unsigned 32-bit integer in network order

int packet_send	(	struct peapod_packet	packet,
		struct iface_t *	iface
	)

Send an EAPOL packet on a network interface.

May execute an egress script.

Parameters

packet	A struct peapod_packet representing an EAPOL packet
iface	Pointer to a struct iface_t representing an interface

Returns

The number of bytes successfully sent

struct peapod_packet packet_recvmsg

(

struct iface_t *

iface

)

Receive an EAPOL packet on a network interface.

Returns

A struct peapod_packet representing an EAPOL packet with its len field set to one of the following:

1. the number of bytes successfully received (if at least 60),
2. -1 if an error occurred while receiving,
3. -2 if fewer than 60 bytes were received (i.e. the EAPOL packet was smaller than the minimum Ethernet frame size of 64 bytes, as the 4-byte FCS is not included), or
4. -3 if the packet was too big to fit in the main EAPOL packet buffer (i.e. the MTU was ignored).

Note

If at least 60 bytes were successfully received, the result will have Ethernet, EAPOL, and EAP metadata in its other fields.

Variable Documentation

const struct decode_t eapol_types[]

static

Initial value:

= {
        { EAPOL_EAP,                    "EAPOL-EAP" },
        { EAPOL_START,                  "EAPOL-Start" },
        { EAPOL_LOGOFF,                 "EAPOL-Logoff" },
        { EAPOL_KEY,                    "EAPOL-Key" },
        { EAPOL_ENCAPSULATED_ASF_ALERT, "EAPOL-Encapsulated-ASF-Alert" },
        { EAPOL_MKA,                    "EAPOL-MKA" },
        { EAPOL_ANNOUNCEMENT_GENERIC,   "EAPOL-Announcement (Generic)" },
        { EAPOL_ANNOUNCEMENT_SPECIFIC,  "EAPOL-Announcement (Specific)" },
        { EAPOL_ANNOUNCEMENT_REQ,       "EAPOL-Announcement-Req" },
        { 0, NULL }
}

EAPOL Packet Type descriptions.

See also

IEEE Std 802.1X-2010 §11.3.2

const struct decode_t eap_codes[]

static

Initial value:

= {
        { EAP_CODE_REQUEST,             "Request" },
        { EAP_CODE_RESPONSE,            "Response" },
        { EAP_CODE_SUCCESS,             "Success" },
        { EAP_CODE_FAILURE,             "Failure" },
        { 0, NULL }
}

EAP Code descriptions.

See also

RFC 2284 §2.2

const struct decode_t eap_types[]

static

Initial value:

= {
        { EAP_TYPE_IDENTITY,            "Identity" },
        { EAP_TYPE_NOTIFICATION,        "Notification" },
        { EAP_TYPE_NAK,                 "Nak (Response only)" },
        { EAP_TYPE_MD5_CHALLENGE,       "MD5-Challenge" },
        { EAP_TYPE_OTP,                 "One Time Password (OTP)" },
        { EAP_TYPE_GTC,                 "Generic Token Card (GTC)" },
        { EAP_TYPE_TLS,                 "EAP TLS" },
        { EAP_TYPE_SIM,                 "EAP-SIM" },
        { EAP_TYPE_TTLS,                "EAP-TTLS" },
        { EAP_TYPE_AKA_OLD,             "EAP-AKA" },
        { EAP_TYPE_PEAP,                "PEAP" },
        { EAP_TYPE_MS_CHAP_V2,          "EAP MS-CHAP-V2" },
        { EAP_TYPE_MS_CHAP_V2_OLD,      "EAP MS-CHAP V2" },
        { EAP_TYPE_FAST,                "EAP-FAST" },
        { EAP_TYPE_IKEV2,               "EAP-IKEv2"},
        { EAP_TYPE_EXPANDED_TYPES,      "Expanded Types" },
        { EAP_TYPE_EXPERIMENTAL_USE,    "Experimental use" },
        { 0, NULL }
}

EAP-Request/Response Type descriptions.

The text of the descriptions is as stated in the relevant RFCs.

const struct decode_t eapol_key_types[]

static

Initial value:

= {
        { EAPOL_KEY_TYPE_RC4,           "RC4" },
        { EAPOL_KEY_TYPE_IEEE_80211,    "IEEE 802.11" },
        { 0, NULL }
}

Descriptions for EAPOL-Key Descriptor Type.

See also

IEEE Std 802.1X-2010 §11.9