android_kernel_samsung_msm8976/lib/qmi_encdec.c

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/* Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 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.
*
*/
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/string.h>
#include <linux/qmi_encdec.h>
#include "qmi_encdec_priv.h"
#define TLV_LEN_SIZE sizeof(uint16_t)
#define TLV_TYPE_SIZE sizeof(uint8_t)
#define OPTIONAL_TLV_TYPE_START 0x10
#ifdef CONFIG_QMI_ENCDEC_DEBUG
#define qmi_encdec_dump(prefix_str, buf, buf_len) do { \
const u8 *ptr = buf; \
int i, linelen, remaining = buf_len; \
int rowsize = 16, groupsize = 1; \
unsigned char linebuf[256]; \
for (i = 0; i < buf_len; i += rowsize) { \
linelen = min(remaining, rowsize); \
remaining -= linelen; \
hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, \
linebuf, sizeof(linebuf), false); \
pr_debug("%s: %s\n", prefix_str, linebuf); \
} \
} while (0)
#define QMI_ENCODE_LOG_MSG(buf, buf_len) do { \
qmi_encdec_dump("QMI_ENCODE_MSG", buf, buf_len); \
} while (0)
#define QMI_DECODE_LOG_MSG(buf, buf_len) do { \
qmi_encdec_dump("QMI_DECODE_MSG", buf, buf_len); \
} while (0)
#define QMI_ENCODE_LOG_ELEM(level, elem_len, elem_size, buf) do { \
pr_debug("QMI_ENCODE_ELEM lvl: %d, len: %d, size: %d\n", \
level, elem_len, elem_size); \
qmi_encdec_dump("QMI_ENCODE_ELEM", buf, (elem_len * elem_size)); \
} while (0)
#define QMI_DECODE_LOG_ELEM(level, elem_len, elem_size, buf) do { \
pr_debug("QMI_DECODE_ELEM lvl: %d, len: %d, size: %d\n", \
level, elem_len, elem_size); \
qmi_encdec_dump("QMI_DECODE_ELEM", buf, (elem_len * elem_size)); \
} while (0)
#define QMI_ENCODE_LOG_TLV(tlv_type, tlv_len) do { \
pr_debug("QMI_ENCODE_TLV type: %d, len: %d\n", tlv_type, tlv_len); \
} while (0)
#define QMI_DECODE_LOG_TLV(tlv_type, tlv_len) do { \
pr_debug("QMI_DECODE_TLV type: %d, len: %d\n", tlv_type, tlv_len); \
} while (0)
#else
#define QMI_ENCODE_LOG_MSG(buf, buf_len) { }
#define QMI_DECODE_LOG_MSG(buf, buf_len) { }
#define QMI_ENCODE_LOG_ELEM(level, elem_len, elem_size, buf) { }
#define QMI_DECODE_LOG_ELEM(level, elem_len, elem_size, buf) { }
#define QMI_ENCODE_LOG_TLV(tlv_type, tlv_len) { }
#define QMI_DECODE_LOG_TLV(tlv_type, tlv_len) { }
#endif
static int _qmi_kernel_encode(struct elem_info *ei_array,
void *out_buf, void *in_c_struct,
uint32_t out_buf_len, int enc_level);
static int _qmi_kernel_decode(struct elem_info *ei_array,
void *out_c_struct,
void *in_buf, uint32_t in_buf_len,
int dec_level);
static struct elem_info *skip_to_next_elem(struct elem_info *ei_array,
int level);
/**
* qmi_calc_max_msg_len() - Calculate the maximum length of a QMI message
* @ei_array: Struct info array describing the structure.
* @level: Level to identify the depth of the nested structures.
*
* @return: expected maximum length of the QMI message or 0 on failure.
*/
static int qmi_calc_max_msg_len(struct elem_info *ei_array,
int level)
{
int max_msg_len = 0;
struct elem_info *temp_ei;
if (!ei_array)
return max_msg_len;
for (temp_ei = ei_array; temp_ei->data_type != QMI_EOTI; temp_ei++) {
/* Flag to identify the optional element is not encoded */
if (temp_ei->data_type == QMI_OPT_FLAG)
continue;
if (temp_ei->data_type == QMI_DATA_LEN) {
max_msg_len += (temp_ei->elem_size == sizeof(uint8_t) ?
sizeof(uint8_t) : sizeof(uint16_t));
continue;
} else if (temp_ei->data_type == QMI_STRUCT) {
max_msg_len += (temp_ei->elem_len *
qmi_calc_max_msg_len(temp_ei->ei_array,
(level + 1)));
} else if (temp_ei->data_type == QMI_STRING) {
if (level > 1)
max_msg_len += temp_ei->elem_len <= U8_MAX ?
sizeof(uint8_t) : sizeof(uint16_t);
max_msg_len += temp_ei->elem_len * temp_ei->elem_size;
} else {
max_msg_len += (temp_ei->elem_len * temp_ei->elem_size);
}
/*
* Type & Length info. not prepended for elements in the
* nested structure.
*/
if (level == 1)
max_msg_len += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
}
return max_msg_len;
}
/**
* qmi_calc_min_msg_len() - Calculate the minimum length of a QMI message
* @ei_array: Struct info array describing the structure.
* @level: Level to identify the depth of the nested structures.
*
* @return: expected minimum length of the QMI message or 0 on failure.
*/
static int qmi_calc_min_msg_len(struct elem_info *ei_array,
int level)
{
int min_msg_len = 0;
struct elem_info *temp_ei = ei_array;
if (!ei_array)
return min_msg_len;
while (temp_ei->data_type != QMI_EOTI) {
/* Optional elements do not count in minimum length */
if (temp_ei->data_type == QMI_OPT_FLAG) {
temp_ei = skip_to_next_elem(temp_ei, level);
continue;
}
if (temp_ei->data_type == QMI_DATA_LEN) {
min_msg_len += (temp_ei->elem_size == sizeof(uint8_t) ?
sizeof(uint8_t) : sizeof(uint16_t));
temp_ei++;
continue;
} else if (temp_ei->data_type == QMI_STRUCT) {
min_msg_len += qmi_calc_min_msg_len(temp_ei->ei_array,
(level + 1));
temp_ei++;
} else if (temp_ei->data_type == QMI_STRING) {
if (level > 1)
min_msg_len += temp_ei->elem_len <= U8_MAX ?
sizeof(uint8_t) : sizeof(uint16_t);
min_msg_len += temp_ei->elem_len * temp_ei->elem_size;
temp_ei++;
} else {
min_msg_len += (temp_ei->elem_len * temp_ei->elem_size);
temp_ei++;
}
/*
* Type & Length info. not prepended for elements in the
* nested structure.
*/
if (level == 1)
min_msg_len += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
}
return min_msg_len;
}
/**
* qmi_verify_max_msg_len() - Verify the maximum length of a QMI message
* @desc: Pointer to structure descriptor.
*
* @return: true if the maximum message length embedded in structure
* descriptor matches the calculated value, else false.
*/
bool qmi_verify_max_msg_len(struct msg_desc *desc)
{
int calc_max_msg_len;
if (!desc)
return false;
calc_max_msg_len = qmi_calc_max_msg_len(desc->ei_array, 1);
if (calc_max_msg_len != desc->max_msg_len) {
pr_err("%s: Calc. len %d != Passed len %d\n",
__func__, calc_max_msg_len, desc->max_msg_len);
return false;
}
return true;
}
/**
* qmi_kernel_encode() - Encode to QMI message wire format
* @desc: Pointer to structure descriptor.
* @out_buf: Buffer to hold the encoded QMI message.
* @out_buf_len: Length of the out buffer.
* @in_c_struct: C Structure to be encoded.
*
* @return: size of encoded message on success, < 0 for error.
*/
int qmi_kernel_encode(struct msg_desc *desc,
void *out_buf, uint32_t out_buf_len,
void *in_c_struct)
{
int enc_level = 1;
int ret, calc_max_msg_len, calc_min_msg_len;
if (!desc)
return -EINVAL;
/* Check the possibility of a zero length QMI message */
if (!in_c_struct) {
calc_min_msg_len = qmi_calc_min_msg_len(desc->ei_array, 1);
if (calc_min_msg_len) {
pr_err("%s: Calc. len %d != 0, but NULL in_c_struct\n",
__func__, calc_min_msg_len);
return -EINVAL;
} else {
return 0;
}
}
/*
* Not a zero-length message. Ensure the output buffer and
* element information array are not NULL.
*/
if (!out_buf || !desc->ei_array)
return -EINVAL;
if (desc->max_msg_len < out_buf_len)
return -ETOOSMALL;
ret = _qmi_kernel_encode(desc->ei_array, out_buf,
in_c_struct, out_buf_len, enc_level);
if (ret == -ETOOSMALL) {
calc_max_msg_len = qmi_calc_max_msg_len(desc->ei_array, 1);
pr_err("%s: Calc. len %d != Out buf len %d\n",
__func__, calc_max_msg_len, out_buf_len);
}
return ret;
}
EXPORT_SYMBOL(qmi_kernel_encode);
/**
* qmi_encode_basic_elem() - Encodes elements of basic/primary data type
* @buf_dst: Buffer to store the encoded information.
* @buf_src: Buffer containing the elements to be encoded.
* @elem_len: Number of elements, in the buf_src, to be encoded.
* @elem_size: Size of a single instance of the element to be encoded.
*
* @return: number of bytes of encoded information.
*
* This function encodes the "elem_len" number of data elements, each of
* size "elem_size" bytes from the source buffer "buf_src" and stores the
* encoded information in the destination buffer "buf_dst". The elements are
* of primary data type which include uint8_t - uint64_t or similar. This
* function returns the number of bytes of encoded information.
*/
static int qmi_encode_basic_elem(void *buf_dst, void *buf_src,
uint32_t elem_len, uint32_t elem_size)
{
uint32_t i, rc = 0;
for (i = 0; i < elem_len; i++) {
QMI_ENCDEC_ENCODE_N_BYTES(buf_dst, buf_src, elem_size);
rc += elem_size;
}
return rc;
}
/**
* qmi_encode_struct_elem() - Encodes elements of struct data type
* @ei_array: Struct info array descibing the struct element.
* @buf_dst: Buffer to store the encoded information.
* @buf_src: Buffer containing the elements to be encoded.
* @elem_len: Number of elements, in the buf_src, to be encoded.
* @out_buf_len: Available space in the encode buffer.
* @enc_level: Depth of the nested structure from the main structure.
*
* @return: Mumber of bytes of encoded information, on success.
* < 0 on error.
*
* This function encodes the "elem_len" number of struct elements, each of
* size "ei_array->elem_size" bytes from the source buffer "buf_src" and
* stores the encoded information in the destination buffer "buf_dst". The
* elements are of struct data type which includes any C structure. This
* function returns the number of bytes of encoded information.
*/
static int qmi_encode_struct_elem(struct elem_info *ei_array,
void *buf_dst, void *buf_src,
uint32_t elem_len, uint32_t out_buf_len,
int enc_level)
{
int i, rc, encoded_bytes = 0;
struct elem_info *temp_ei = ei_array;
for (i = 0; i < elem_len; i++) {
rc = _qmi_kernel_encode(temp_ei->ei_array, buf_dst, buf_src,
(out_buf_len - encoded_bytes),
enc_level);
if (rc < 0) {
pr_err("%s: STRUCT Encode failure\n", __func__);
return rc;
}
buf_dst = buf_dst + rc;
buf_src = buf_src + temp_ei->elem_size;
encoded_bytes += rc;
}
return encoded_bytes;
}
/**
* qmi_encode_string_elem() - Encodes elements of string data type
* @ei_array: Struct info array descibing the string element.
* @buf_dst: Buffer to store the encoded information.
* @buf_src: Buffer containing the elements to be encoded.
* @out_buf_len: Available space in the encode buffer.
* @enc_level: Depth of the string element from the main structure.
*
* @return: Mumber of bytes of encoded information, on success.
* < 0 on error.
*
* This function encodes a string element of maximum length "ei_array->elem_len"
* bytes from the source buffer "buf_src" and stores the encoded information in
* the destination buffer "buf_dst". This function returns the number of bytes
* of encoded information.
*/
static int qmi_encode_string_elem(struct elem_info *ei_array,
void *buf_dst, void *buf_src,
uint32_t out_buf_len, int enc_level)
{
int rc;
int encoded_bytes = 0;
struct elem_info *temp_ei = ei_array;
uint32_t string_len = 0;
uint32_t string_len_sz = 0;
string_len = strlen(buf_src);
string_len_sz = temp_ei->elem_len <= U8_MAX ?
sizeof(uint8_t) : sizeof(uint16_t);
if (string_len > temp_ei->elem_len) {
pr_err("%s: String to be encoded is longer - %d > %d\n",
__func__, string_len, temp_ei->elem_len);
return -EINVAL;
}
if (enc_level == 1) {
if (string_len + TLV_LEN_SIZE + TLV_TYPE_SIZE >
out_buf_len) {
pr_err("%s: Output len %d > Out Buf len %d\n",
__func__, string_len, out_buf_len);
return -ETOOSMALL;
}
} else {
if (string_len + string_len_sz > out_buf_len) {
pr_err("%s: Output len %d > Out Buf len %d\n",
__func__, string_len, out_buf_len);
return -ETOOSMALL;
}
rc = qmi_encode_basic_elem(buf_dst, &string_len,
1, string_len_sz);
encoded_bytes += rc;
}
rc = qmi_encode_basic_elem(buf_dst + encoded_bytes, buf_src,
string_len, temp_ei->elem_size);
encoded_bytes += rc;
QMI_ENCODE_LOG_ELEM(enc_level, string_len, temp_ei->elem_size, buf_src);
return encoded_bytes;
}
/**
* skip_to_next_elem() - Skip to next element in the structure to be encoded
* @ei_array: Struct info describing the element to be skipped.
* @level: Depth level of encoding/decoding to identify nested structures.
*
* @return: Struct info of the next element that can be encoded.
*
* This function is used while encoding optional elements. If the flag
* corresponding to an optional element is not set, then encoding the
* optional element can be skipped. This function can be used to perform
* that operation.
*/
static struct elem_info *skip_to_next_elem(struct elem_info *ei_array,
int level)
{
struct elem_info *temp_ei = ei_array;
uint8_t tlv_type;
if (level > 1) {
temp_ei = temp_ei + 1;
} else {
do {
tlv_type = temp_ei->tlv_type;
temp_ei = temp_ei + 1;
} while (tlv_type == temp_ei->tlv_type);
}
return temp_ei;
}
/**
* _qmi_kernel_encode() - Core Encode Function
* @ei_array: Struct info array describing the structure to be encoded.
* @out_buf: Buffer to hold the encoded QMI message.
* @in_c_struct: Pointer to the C structure to be encoded.
* @out_buf_len: Available space in the encode buffer.
* @enc_level: Encode level to indicate the depth of the nested structure,
* within the main structure, being encoded.
*
* @return: Number of bytes of encoded information, on success.
* < 0 on error.
*/
static int _qmi_kernel_encode(struct elem_info *ei_array,
void *out_buf, void *in_c_struct,
uint32_t out_buf_len, int enc_level)
{
struct elem_info *temp_ei = ei_array;
uint8_t opt_flag_value = 0;
uint32_t data_len_value = 0, data_len_sz;
uint8_t *buf_dst = (uint8_t *)out_buf;
uint8_t *tlv_pointer;
uint32_t tlv_len;
uint8_t tlv_type;
uint32_t encoded_bytes = 0;
void *buf_src;
int encode_tlv = 0;
int rc;
tlv_pointer = buf_dst;
tlv_len = 0;
if (enc_level == 1)
buf_dst = buf_dst + (TLV_LEN_SIZE + TLV_TYPE_SIZE);
while (temp_ei->data_type != QMI_EOTI) {
buf_src = in_c_struct + temp_ei->offset;
tlv_type = temp_ei->tlv_type;
if (temp_ei->is_array == NO_ARRAY) {
data_len_value = 1;
} else if (temp_ei->is_array == STATIC_ARRAY) {
data_len_value = temp_ei->elem_len;
} else if (data_len_value <= 0 ||
temp_ei->elem_len < data_len_value) {
pr_err("%s: Invalid data length\n", __func__);
return -EINVAL;
}
switch (temp_ei->data_type) {
case QMI_OPT_FLAG:
rc = qmi_encode_basic_elem(&opt_flag_value, buf_src,
1, sizeof(uint8_t));
if (opt_flag_value)
temp_ei = temp_ei + 1;
else
temp_ei = skip_to_next_elem(temp_ei, enc_level);
break;
case QMI_DATA_LEN:
memcpy(&data_len_value, buf_src, temp_ei->elem_size);
data_len_sz = temp_ei->elem_size == sizeof(uint8_t) ?
sizeof(uint8_t) : sizeof(uint16_t);
/* Check to avoid out of range buffer access */
if ((data_len_sz + encoded_bytes + TLV_LEN_SIZE +
TLV_TYPE_SIZE) > out_buf_len) {
pr_err("%s: Too Small Buffer @DATA_LEN\n",
__func__);
return -ETOOSMALL;
}
rc = qmi_encode_basic_elem(buf_dst, &data_len_value,
1, data_len_sz);
UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
encoded_bytes, tlv_len, encode_tlv, rc);
if (!data_len_value)
temp_ei = skip_to_next_elem(temp_ei, enc_level);
else
encode_tlv = 0;
break;
case QMI_UNSIGNED_1_BYTE:
case QMI_UNSIGNED_2_BYTE:
case QMI_UNSIGNED_4_BYTE:
case QMI_UNSIGNED_8_BYTE:
case QMI_SIGNED_2_BYTE_ENUM:
case QMI_SIGNED_4_BYTE_ENUM:
/* Check to avoid out of range buffer access */
if (((data_len_value * temp_ei->elem_size) +
encoded_bytes + TLV_LEN_SIZE + TLV_TYPE_SIZE) >
out_buf_len) {
pr_err("%s: Too Small Buffer @data_type:%d\n",
__func__, temp_ei->data_type);
return -ETOOSMALL;
}
rc = qmi_encode_basic_elem(buf_dst, buf_src,
data_len_value, temp_ei->elem_size);
QMI_ENCODE_LOG_ELEM(enc_level, data_len_value,
temp_ei->elem_size, buf_src);
UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
encoded_bytes, tlv_len, encode_tlv, rc);
break;
case QMI_STRUCT:
rc = qmi_encode_struct_elem(temp_ei, buf_dst, buf_src,
data_len_value, (out_buf_len - encoded_bytes),
(enc_level + 1));
if (rc < 0)
return rc;
UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
encoded_bytes, tlv_len, encode_tlv, rc);
break;
case QMI_STRING:
rc = qmi_encode_string_elem(temp_ei, buf_dst, buf_src,
out_buf_len - encoded_bytes, enc_level);
if (rc < 0)
return rc;
UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
encoded_bytes, tlv_len, encode_tlv, rc);
break;
default:
pr_err("%s: Unrecognized data type\n", __func__);
return -EINVAL;
}
if (encode_tlv && enc_level == 1) {
QMI_ENCDEC_ENCODE_TLV(tlv_type, tlv_len, tlv_pointer);
QMI_ENCODE_LOG_TLV(tlv_type, tlv_len);
encoded_bytes += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
tlv_pointer = buf_dst;
tlv_len = 0;
buf_dst = buf_dst + TLV_LEN_SIZE + TLV_TYPE_SIZE;
encode_tlv = 0;
}
}
QMI_ENCODE_LOG_MSG(out_buf, encoded_bytes);
return encoded_bytes;
}
/**
* qmi_kernel_decode() - Decode to C Structure format
* @desc: Pointer to structure descriptor.
* @out_c_struct: Buffer to hold the decoded C structure.
* @in_buf: Buffer containg the QMI message to be decoded.
* @in_buf_len: Length of the incoming QMI message.
*
* @return: 0 on success, < 0 on error.
*/
int qmi_kernel_decode(struct msg_desc *desc, void *out_c_struct,
void *in_buf, uint32_t in_buf_len)
{
int dec_level = 1;
int rc = 0;
if (!desc || !desc->ei_array)
return -EINVAL;
if (!out_c_struct || !in_buf || !in_buf_len)
return -EINVAL;
if (desc->max_msg_len < in_buf_len)
return -EINVAL;
rc = _qmi_kernel_decode(desc->ei_array, out_c_struct,
in_buf, in_buf_len, dec_level);
if (rc < 0)
return rc;
else
return 0;
}
EXPORT_SYMBOL(qmi_kernel_decode);
/**
* qmi_decode_basic_elem() - Decodes elements of basic/primary data type
* @buf_dst: Buffer to store the decoded element.
* @buf_src: Buffer containing the elements in QMI wire format.
* @elem_len: Number of elements to be decoded.
* @elem_size: Size of a single instance of the element to be decoded.
*
* @return: Total size of the decoded data elements, in bytes.
*
* This function decodes the "elem_len" number of elements in QMI wire format,
* each of size "elem_size" bytes from the source buffer "buf_src" and stores
* the decoded elements in the destination buffer "buf_dst". The elements are
* of primary data type which include uint8_t - uint64_t or similar. This
* function returns the number of bytes of decoded information.
*/
static int qmi_decode_basic_elem(void *buf_dst, void *buf_src,
uint32_t elem_len, uint32_t elem_size)
{
uint32_t i, rc = 0;
for (i = 0; i < elem_len; i++) {
QMI_ENCDEC_DECODE_N_BYTES(buf_dst, buf_src, elem_size);
rc += elem_size;
}
return rc;
}
/**
* qmi_decode_struct_elem() - Decodes elements of struct data type
* @ei_array: Struct info array descibing the struct element.
* @buf_dst: Buffer to store the decoded element.
* @buf_src: Buffer containing the elements in QMI wire format.
* @elem_len: Number of elements to be decoded.
* @tlv_len: Total size of the encoded inforation corresponding to
* this struct element.
* @dec_level: Depth of the nested structure from the main structure.
*
* @return: Total size of the decoded data elements, on success.
* < 0 on error.
*
* This function decodes the "elem_len" number of elements in QMI wire format,
* each of size "(tlv_len/elem_len)" bytes from the source buffer "buf_src"
* and stores the decoded elements in the destination buffer "buf_dst". The
* elements are of struct data type which includes any C structure. This
* function returns the number of bytes of decoded information.
*/
static int qmi_decode_struct_elem(struct elem_info *ei_array, void *buf_dst,
void *buf_src, uint32_t elem_len,
uint32_t tlv_len, int dec_level)
{
int i, rc, decoded_bytes = 0;
struct elem_info *temp_ei = ei_array;
for (i = 0; i < elem_len && decoded_bytes < tlv_len; i++) {
rc = _qmi_kernel_decode(temp_ei->ei_array, buf_dst, buf_src,
(tlv_len - decoded_bytes), dec_level);
if (rc < 0)
return rc;
buf_src = buf_src + rc;
buf_dst = buf_dst + temp_ei->elem_size;
decoded_bytes += rc;
}
if ((dec_level <= 2 && decoded_bytes != tlv_len) ||
(dec_level > 2 && (i < elem_len || decoded_bytes > tlv_len))) {
pr_err("%s: Fault in decoding: dl(%d), db(%d), tl(%d), i(%d), el(%d)\n",
__func__, dec_level, decoded_bytes, tlv_len,
i, elem_len);
return -EFAULT;
}
return decoded_bytes;
}
/**
* qmi_decode_string_elem() - Decodes elements of string data type
* @ei_array: Struct info array descibing the string element.
* @buf_dst: Buffer to store the decoded element.
* @buf_src: Buffer containing the elements in QMI wire format.
* @tlv_len: Total size of the encoded inforation corresponding to
* this string element.
* @dec_level: Depth of the string element from the main structure.
*
* @return: Total size of the decoded data elements, on success.
* < 0 on error.
*
* This function decodes the string element of maximum length
* "ei_array->elem_len" from the source buffer "buf_src" and puts it into
* the destination buffer "buf_dst". This function returns number of bytes
* decoded from the input buffer.
*/
static int qmi_decode_string_elem(struct elem_info *ei_array, void *buf_dst,
void *buf_src, uint32_t tlv_len,
int dec_level)
{
int rc;
int decoded_bytes = 0;
uint32_t string_len = 0;
uint32_t string_len_sz = 0;
struct elem_info *temp_ei = ei_array;
if (dec_level == 1) {
string_len = tlv_len;
} else {
string_len_sz = temp_ei->elem_len <= U8_MAX ?
sizeof(uint8_t) : sizeof(uint16_t);
rc = qmi_decode_basic_elem(&string_len, buf_src,
1, string_len_sz);
decoded_bytes += rc;
}
if (string_len > temp_ei->elem_len) {
pr_err("%s: String len %d > Max Len %d\n",
__func__, string_len, temp_ei->elem_len);
return -ETOOSMALL;
} else if (string_len > tlv_len) {
pr_err("%s: String len %d > Input Buffer Len %d\n",
__func__, string_len, tlv_len);
return -EFAULT;
}
rc = qmi_decode_basic_elem(buf_dst, buf_src + decoded_bytes,
string_len, temp_ei->elem_size);
*((char *)buf_dst + string_len) = '\0';
decoded_bytes += rc;
QMI_DECODE_LOG_ELEM(dec_level, string_len, temp_ei->elem_size, buf_dst);
return decoded_bytes;
}
/**
* find_ei() - Find element info corresponding to TLV Type
* @ei_array: Struct info array of the message being decoded.
* @type: TLV Type of the element being searched.
*
* @return: Pointer to struct info, if found
*
* Every element that got encoded in the QMI message will have a type
* information associated with it. While decoding the QMI message,
* this function is used to find the struct info regarding the element
* that corresponds to the type being decoded.
*/
static struct elem_info *find_ei(struct elem_info *ei_array,
uint32_t type)
{
struct elem_info *temp_ei = ei_array;
while (temp_ei->data_type != QMI_EOTI) {
if (temp_ei->tlv_type == (uint8_t)type)
return temp_ei;
temp_ei = temp_ei + 1;
}
return NULL;
}
/**
* _qmi_kernel_decode() - Core Decode Function
* @ei_array: Struct info array describing the structure to be decoded.
* @out_c_struct: Buffer to hold the decoded C struct
* @in_buf: Buffer containing the QMI message to be decoded
* @in_buf_len: Length of the QMI message to be decoded
* @dec_level: Decode level to indicate the depth of the nested structure,
* within the main structure, being decoded
*
* @return: Number of bytes of decoded information, on success
* < 0 on error.
*/
static int _qmi_kernel_decode(struct elem_info *ei_array,
void *out_c_struct,
void *in_buf, uint32_t in_buf_len,
int dec_level)
{
struct elem_info *temp_ei = ei_array;
uint8_t opt_flag_value = 1;
uint32_t data_len_value = 0, data_len_sz = 0;
uint8_t *buf_dst = out_c_struct;
uint8_t *tlv_pointer;
uint32_t tlv_len = 0;
uint32_t tlv_type;
uint32_t decoded_bytes = 0;
void *buf_src = in_buf;
int rc;
QMI_DECODE_LOG_MSG(in_buf, in_buf_len);
while (decoded_bytes < in_buf_len) {
if (dec_level >= 2 && temp_ei->data_type == QMI_EOTI)
return decoded_bytes;
if (dec_level == 1) {
tlv_pointer = buf_src;
QMI_ENCDEC_DECODE_TLV(&tlv_type,
&tlv_len, tlv_pointer);
QMI_DECODE_LOG_TLV(tlv_type, tlv_len);
buf_src += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
decoded_bytes += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
temp_ei = find_ei(ei_array, tlv_type);
if (!temp_ei && (tlv_type < OPTIONAL_TLV_TYPE_START)) {
pr_err("%s: Inval element info\n", __func__);
return -EINVAL;
} else if (!temp_ei) {
UPDATE_DECODE_VARIABLES(buf_src,
decoded_bytes, tlv_len);
continue;
}
} else {
/*
* No length information for elements in nested
* structures. So use remaining decodable buffer space.
*/
tlv_len = in_buf_len - decoded_bytes;
}
buf_dst = out_c_struct + temp_ei->offset;
if (temp_ei->data_type == QMI_OPT_FLAG) {
memcpy(buf_dst, &opt_flag_value, sizeof(uint8_t));
temp_ei = temp_ei + 1;
buf_dst = out_c_struct + temp_ei->offset;
}
if (temp_ei->data_type == QMI_DATA_LEN) {
data_len_sz = temp_ei->elem_size == sizeof(uint8_t) ?
sizeof(uint8_t) : sizeof(uint16_t);
rc = qmi_decode_basic_elem(&data_len_value, buf_src,
1, data_len_sz);
memcpy(buf_dst, &data_len_value, sizeof(uint32_t));
temp_ei = temp_ei + 1;
buf_dst = out_c_struct + temp_ei->offset;
tlv_len -= data_len_sz;
UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
}
if (temp_ei->is_array == NO_ARRAY) {
data_len_value = 1;
} else if (temp_ei->is_array == STATIC_ARRAY) {
data_len_value = temp_ei->elem_len;
} else if (data_len_value > temp_ei->elem_len) {
pr_err("%s: Data len %d > max spec %d\n",
__func__, data_len_value, temp_ei->elem_len);
return -ETOOSMALL;
}
switch (temp_ei->data_type) {
case QMI_UNSIGNED_1_BYTE:
case QMI_UNSIGNED_2_BYTE:
case QMI_UNSIGNED_4_BYTE:
case QMI_UNSIGNED_8_BYTE:
case QMI_SIGNED_2_BYTE_ENUM:
case QMI_SIGNED_4_BYTE_ENUM:
rc = qmi_decode_basic_elem(buf_dst, buf_src,
data_len_value, temp_ei->elem_size);
QMI_DECODE_LOG_ELEM(dec_level, data_len_value,
temp_ei->elem_size, buf_dst);
UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
break;
case QMI_STRUCT:
rc = qmi_decode_struct_elem(temp_ei, buf_dst, buf_src,
data_len_value, tlv_len, (dec_level + 1));
if (rc < 0)
return rc;
UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
break;
case QMI_STRING:
rc = qmi_decode_string_elem(temp_ei, buf_dst, buf_src,
tlv_len, dec_level);
if (rc < 0)
return rc;
UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
break;
default:
pr_err("%s: Unrecognized data type\n", __func__);
return -EINVAL;
}
temp_ei = temp_ei + 1;
}
return decoded_bytes;
}
MODULE_DESCRIPTION("QMI kernel enc/dec");
MODULE_LICENSE("GPL v2");