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mpdu: Rework to a zero-copy based framework

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This commit is contained in:
Denis Kenzior 2014-12-17 17:44:44 -06:00
parent b38bf4d0b7
commit b22f93203c
2 changed files with 96 additions and 126 deletions
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159
src/mpdu.c
View File

@ -26,127 +26,77 @@
#include <ell/ell.h> #include <ell/ell.h>
#include "ie.h"
#include "mpdu.h" #include "mpdu.h"
static inline unsigned char bit_field(unsigned char oct, int start, int num) static bool validate_mgmt_header(const struct mpdu *mpdu, int len, int *offset)
{ {
unsigned char mask = (1 << num) - 1; /* Duration + Address1 + Address 2 + Address 3 + SeqCntrl */
if (len < *offset + 22)
return (oct >> start) & mask;
}
static inline bool next_byte(const unsigned char *mpdu, int len,
int *offset, unsigned char *holder)
{
if (len == *offset)
return false; return false;
*holder = mpdu[*offset]; *offset += 22;
*offset = *offset + 1;
if (!mpdu->fc.order)
return true;
if (len < *offset + 4)
return false;
*offset += 4;
return true; return true;
} }
static inline bool next_2bytes(const unsigned char *mpdu, int len, static bool validate_authentication_mgmt_mpdu(const struct mpdu *mpdu,
int *offset, uint16_t *holder) int len, int *offset)
{ {
if (len < *offset + 2) if (len < *offset + 6)
return false; return false;
*holder = L_LE16_TO_CPU(*(uint16_t *)(mpdu + *offset)); switch (mpdu->auth.algorithm) {
*offset = *offset + 2; case MPDU_AUTH_ALGO_OPEN_SYSTEM:
return *offset <= len;
case MPDU_AUTH_ALGO_SHARED_KEY:
if (mpdu->auth.transaction_sequence < 2 ||
mpdu->auth.transaction_sequence > 3)
return *offset == len;
return true; if (len < *offset + 2)
}
static inline bool next_data(const unsigned char *mpdu, int len,
int *offset, unsigned char *holder, int t_len)
{
if (len < *offset + t_len)
return false;
memcpy(holder, mpdu + *offset, t_len);
*offset += t_len;
return true;
}
static bool decode_mgmt_header(const unsigned char *mpdu, int len,
int *offset, struct mpdu *out)
{
uint16_t sequence_control;
if (!next_2bytes(mpdu, len, offset, &out->mgmt_hdr.duration))
return false;
if (!next_data(mpdu, len, offset, out->mgmt_hdr.address_1, 6))
return false;
if (!next_data(mpdu, len, offset, out->mgmt_hdr.address_2, 6))
return false;
if (!next_data(mpdu, len, offset, out->mgmt_hdr.address_3, 6))
return false;
if (!next_2bytes(mpdu, len, offset, &sequence_control))
return false;
out->mgmt_hdr.fragment_number = sequence_control & 0x0f;
out->mgmt_hdr.sequence_number = sequence_control >> 4;
if (out->fc.order)
*offset += sizeof(uint32_t); /* Skipping ht_control for now */
return true;
}
static bool decode_authentication_mgmt_mpdu(const unsigned char *mpdu,
int len, int *offset, struct mpdu *out)
{
if (!next_2bytes(mpdu, len, offset, &out->auth.algorithm))
return false;
if (!next_2bytes(mpdu, len, offset, &out->auth.transaction_sequence))
return false;
if (!next_2bytes(mpdu, len, offset, &out->auth.status))
return false;
if (out->auth.algorithm == MPDU_AUTH_ALGO_SK) {
if (out->auth.transaction_sequence < 2 &&
out->auth.transaction_sequence > 3)
return true;
if (!next_byte(mpdu, len, offset,
&out->auth.challenge_text_len))
return false; return false;
if (!next_data(mpdu, len, offset, out->auth.challenge_text, *offset += 2;
out->auth.challenge_text_len))
if (mpdu->auth.shared_key_23.element_id !=
IE_TYPE_CHALLENGE_TEXT)
return false; return false;
*offset += mpdu->auth.shared_key_23.challenge_text_len;
return *offset <= len;
default:
return false;
} }
return true; return false;
} }
static bool decode_deauthentication_mgmt_mpdu(const unsigned char *mpdu, static bool validate_deauthentication_mgmt_mpdu(const struct mpdu *mpdu,
int len, int *offset, struct mpdu *out) int len, int *offset)
{ {
return next_2bytes(mpdu, len, offset, &out->deauth.reason_code); *offset += 2;
return *offset <= len;
} }
static bool decode_mgmt_mpdu(const unsigned char *mpdu, int len, static bool validate_mgmt_mpdu(const struct mpdu *mpdu, int len, int *offset)
int *offset, struct mpdu *out)
{ {
if (!decode_mgmt_header(mpdu, len, offset, out)) if (!validate_mgmt_header(mpdu, len, offset))
return false; return false;
switch (out->fc.subtype) { switch (mpdu->fc.subtype) {
case MPDU_MANAGEMENT_SUBTYPE_AUTHENTICATION: case MPDU_MANAGEMENT_SUBTYPE_AUTHENTICATION:
return decode_authentication_mgmt_mpdu(mpdu, len, offset, out); return validate_authentication_mgmt_mpdu(mpdu, len, offset);
case MPDU_MANAGEMENT_SUBTYPE_DEAUTHENTICATION: case MPDU_MANAGEMENT_SUBTYPE_DEAUTHENTICATION:
return decode_deauthentication_mgmt_mpdu(mpdu, len, offset, return validate_deauthentication_mgmt_mpdu(mpdu, len, offset);
out);
default: default:
return false; return false;
} }
@ -154,34 +104,23 @@ static bool decode_mgmt_mpdu(const unsigned char *mpdu, int len,
return true; return true;
} }
bool mpdu_decode(const unsigned char *mpdu, int len, struct mpdu *out) bool mpdu_validate(const unsigned char *frame, int len)
{ {
struct mpdu *mpdu;
int offset; int offset;
if (!mpdu || !out) if (!frame)
return false; return false;
if (len < 2) if (len < 2)
return false; return false;
out->fc.protocol_version = bit_field(mpdu[0], 0, 2);
out->fc.type = bit_field(mpdu[0], 2, 2);
out->fc.subtype = bit_field(mpdu[0], 4, 4);
out->fc.to_ds = bit_field(mpdu[1], 0, 1);
out->fc.from_ds = bit_field(mpdu[1], 1, 1);
out->fc.more_fragments = bit_field(mpdu[1], 2, 1);
out->fc.retry = bit_field(mpdu[1], 3, 1);
out->fc.power_mgmt = bit_field(mpdu[1], 4, 1);
out->fc.more_data = bit_field(mpdu[1], 5, 1);
out->fc.protected_frame = bit_field(mpdu[1], 6, 1);
out->fc.order = bit_field(mpdu[1], 7, 1);
offset = 2; offset = 2;
mpdu = (struct mpdu *) frame;
switch (out->fc.type) { switch (mpdu->fc.type) {
case MPDU_TYPE_MANAGEMENT: case MPDU_TYPE_MANAGEMENT:
return decode_mgmt_mpdu(mpdu, len, &offset, out); return validate_mgmt_mpdu(mpdu, len, &offset);
default: default:
return false; return false;
} }

63
src/mpdu.h
View File

@ -22,6 +22,8 @@
#include <stdint.h> #include <stdint.h>
#include <stdbool.h> #include <stdbool.h>
#include <asm/byteorder.h>
#include <linux/types.h>
/* 802.11, Table 8-1 "Valid type and subtype combinations" */ /* 802.11, Table 8-1 "Valid type and subtype combinations" */
enum mpdu_type { enum mpdu_type {
@ -36,12 +38,13 @@ enum mpdu_management_subtype {
/* 802.11, Section 8.4.1.1 Authentication Algorithm Number field */ /* 802.11, Section 8.4.1.1 Authentication Algorithm Number field */
enum mpdu_authentication_algorithm_number { enum mpdu_authentication_algorithm_number {
MPDU_AUTH_ALGO_OPEN = 0, MPDU_AUTH_ALGO_OPEN_SYSTEM = 0,
MPDU_AUTH_ALGO_SK, MPDU_AUTH_ALGO_SHARED_KEY,
}; };
/* 802.11, Section 8.2.4.1.1, Figure 8-2 */ /* 802.11, Section 8.2.4.1.1, Figure 8-2 */
struct mpdu_fc { struct mpdu_fc {
#if defined(__LITTLE_ENDIAN_BITFIELD)
uint8_t protocol_version:2; uint8_t protocol_version:2;
uint8_t type:2; uint8_t type:2;
uint8_t subtype:4; uint8_t subtype:4;
@ -53,34 +56,62 @@ struct mpdu_fc {
bool more_data:1; bool more_data:1;
bool protected_frame:1; bool protected_frame:1;
bool order:1; bool order:1;
#elif defined (__BIG_ENDIAN_BITFIELD)
uint8_t subtype:4;
uint8_t type:2;
uint8_t protocol_version:2;
bool order:1;
bool protected_frame:1;
bool more_data:1;
bool power_mgmt:1;
bool retry:1;
bool more_fragments:1;
bool from_ds:1;
bool to_ds:1;
#else
#error "Please fix <asm/byteorder.h>"
#endif
} __attribute__ ((packed)); } __attribute__ ((packed));
/* 802.11, Section 8.3.3.1 */ /* 802.11, Section 8.3.3.1 */
struct mpdu_mgmt_header { struct mpdu_mgmt_header {
uint16_t duration; __le16 duration;
unsigned char address_1[6]; unsigned char address_1[6];
unsigned char address_2[6]; unsigned char address_2[6];
unsigned char address_3[6]; unsigned char address_3[6];
uint16_t fragment_number:4; #if defined(__LITTLE_ENDIAN_BITFIELD)
uint16_t sequence_number:12; __le16 fragment_number:4;
uint32_t ht_control; /* ToDo? */ __le16 sequence_number:12;
#elif defined (__BIG_ENDIAN_BITFIELD)
__le16 sequence_number:12;
__le16 fragment_number:4;
#else
#error "Please fix <asm/byteorder.h>"
#endif
__le32 ht_control; /* ToDo? */
} __attribute__ ((packed)); } __attribute__ ((packed));
/* 802.11, Section 8.3.3.11 */ /* 802.11, Section 8.3.3.11 */
struct mpdu_authentication { struct mpdu_authentication {
uint16_t algorithm; __le16 algorithm;
uint16_t transaction_sequence; __le16 transaction_sequence;
uint16_t status; __le16 status;
uint8_t challenge_text_len;
unsigned char challenge_text[253]; union {
struct {
uint8_t element_id;
uint8_t challenge_text_len;
unsigned char challenge_text[253];
} __attribute__ ((packed)) shared_key_23;
};
/* ToDo: FT and SAE parts? */ /* ToDo: FT and SAE parts? */
}; } __attribute__ ((packed));
/* 802.11, Section 8.3.3.12 */ /* 802.11, Section 8.3.3.12 */
struct mpdu_deauthentication { struct mpdu_deauthentication {
uint16_t reason_code; __le16 reason_code;
/* ToDo: Vendor specific IE? MME? */ /* ToDo: Vendor specific IE? MME? */
}; } __attribute__ ((packed));
struct mpdu { struct mpdu {
struct mpdu_fc fc; struct mpdu_fc fc;
@ -89,6 +120,6 @@ struct mpdu {
struct mpdu_authentication auth; struct mpdu_authentication auth;
struct mpdu_deauthentication deauth; struct mpdu_deauthentication deauth;
}; };
}; } __attribute__ ((packed));
bool mpdu_decode(const unsigned char *mpdu, int len, struct mpdu *out); bool mpdu_validate(const unsigned char *mpdu, int len);