OpenWrt – Rev 1
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/*
* netlink/attr.h Netlink Attributes
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation version 2.1
* of the License.
*
* Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
*/
#ifndef NETLINK_ATTR_H_
#define NETLINK_ATTR_H_
#include <netlink/netlink.h>
#include <netlink/object.h>
#include <netlink/addr.h>
#include <netlink/data.h>
#include <netlink/msg.h>
#ifdef __cplusplus
extern "C" {
#endif
struct nl_msg;
/**
* @name Basic Attribute Data Types
* @{
*/
/**
* @ingroup attr
* Basic attribute data types
*
* See \ref attr_datatypes for more details.
*/
enum {
NLA_UNSPEC, /**< Unspecified type, binary data chunk */
NLA_U8, /**< 8 bit integer */
NLA_U16, /**< 16 bit integer */
NLA_U32, /**< 32 bit integer */
NLA_U64, /**< 64 bit integer */
NLA_STRING, /**< NUL terminated character string */
NLA_FLAG, /**< Flag */
NLA_MSECS, /**< Micro seconds (64bit) */
NLA_NESTED, /**< Nested attributes */
__NLA_TYPE_MAX,
};
#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)
/** @} */
/**
* @ingroup attr
* Attribute validation policy.
*
* See \ref attr_datatypes for more details.
*/
struct nla_policy {
/** Type of attribute or NLA_UNSPEC */
uint16_t type;
/** Minimal length of payload required */
uint16_t minlen;
/** Maximal length of payload allowed */
uint16_t maxlen;
};
/* Attribute parsing */
extern int nla_ok(const struct nlattr *, int);
extern struct nlattr * nla_next(const struct nlattr *, int *);
extern int nla_parse(struct nlattr **, int, struct nlattr *,
int, struct nla_policy *);
extern int nla_validate(struct nlattr *, int, int,
struct nla_policy *);
extern struct nlattr * nla_find(struct nlattr *, int, int);
/* Unspecific attribute */
extern struct nlattr * nla_reserve(struct nl_msg *, int, int);
extern int nla_put(struct nl_msg *, int, int, const void *);
/**
* nlmsg_find_attr - find a specific attribute in a netlink message
* @arg nlh netlink message header
* @arg hdrlen length of familiy specific header
* @arg attrtype type of attribute to look for
*
* Returns the first attribute which matches the specified type.
*/
static inline struct nlattr *nlmsg_find_attr(struct nlmsghdr *nlh, int hdrlen, int attrtype)
{
return nla_find(nlmsg_attrdata(nlh, hdrlen),
nlmsg_attrlen(nlh, hdrlen), attrtype);
}
/**
* Return size of attribute whithout padding.
* @arg payload Payload length of attribute.
*
* @code
* <-------- nla_attr_size(payload) --------->
* +------------------+- - -+- - - - - - - - - +- - -+
* | Attribute Header | Pad | Payload | Pad |
* +------------------+- - -+- - - - - - - - - +- - -+
* @endcode
*
* @return Size of attribute in bytes without padding.
*/
static inline int nla_attr_size(int payload)
{
return NLA_HDRLEN + payload;
}
/**
* Return size of attribute including padding.
* @arg payload Payload length of attribute.
*
* @code
* <----------- nla_total_size(payload) ----------->
* +------------------+- - -+- - - - - - - - - +- - -+
* | Attribute Header | Pad | Payload | Pad |
* +------------------+- - -+- - - - - - - - - +- - -+
* @endcode
*
* @return Size of attribute in bytes.
*/
static inline int nla_total_size(int payload)
{
return NLA_ALIGN(nla_attr_size(payload));
}
/**
* Return length of padding at the tail of the attribute.
* @arg payload Payload length of attribute.
*
* @code
* +------------------+- - -+- - - - - - - - - +- - -+
* | Attribute Header | Pad | Payload | Pad |
* +------------------+- - -+- - - - - - - - - +- - -+
* <--->
* @endcode
*
* @return Length of padding in bytes.
*/
static inline int nla_padlen(int payload)
{
return nla_total_size(payload) - nla_attr_size(payload);
}
/**
* Return type of the attribute.
* @arg nla Attribute.
*
* @return Type of attribute.
*/
static inline int nla_type(const struct nlattr *nla)
{
return nla->nla_type & NLA_TYPE_MASK;
}
/**
* Return pointer to the payload section.
* @arg nla Attribute.
*
* @return Pointer to start of payload section.
*/
static inline void *nla_data(const struct nlattr *nla)
{
return (char *) nla + NLA_HDRLEN;
}
/**
* Return length of the payload .
* @arg nla Attribute
*
* @return Length of payload in bytes.
*/
static inline int nla_len(const struct nlattr *nla)
{
return nla->nla_len - NLA_HDRLEN;
}
/**
* Copy attribute payload to another memory area.
* @arg dest Pointer to destination memory area.
* @arg src Attribute
* @arg count Number of bytes to copy at most.
*
* Note: The number of bytes copied is limited by the length of
* the attribute payload.
*
* @return The number of bytes copied to dest.
*/
static inline int nla_memcpy(void *dest, struct nlattr *src, int count)
{
int minlen;
if (!src)
return 0;
minlen = min_t(int, count, nla_len(src));
memcpy(dest, nla_data(src), minlen);
return minlen;
}
/**
* Add abstract data as unspecific attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg data Abstract data object.
*
* Equivalent to nla_put() except that the length of the payload is
* derived from the abstract data object.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_data(struct nl_msg *msg, int attrtype, struct nl_data *data)
{
return nla_put(msg, attrtype, nl_data_get_size(data),
nl_data_get(data));
}
/**
* Add abstract address as unspecific attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg addr Abstract address object.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_addr(struct nl_msg *msg, int attrtype, struct nl_addr *addr)
{
return nla_put(msg, attrtype, nl_addr_get_len(addr),
nl_addr_get_binary_addr(addr));
}
/** @} */
/**
* @name Integer Attributes
*/
/**
* Add 8 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value to store as payload.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_u8(struct nl_msg *msg, int attrtype, uint8_t value)
{
return nla_put(msg, attrtype, sizeof(uint8_t), &value);
}
/**
* Return value of 8 bit integer attribute.
* @arg nla 8 bit integer attribute
*
* @return Payload as 8 bit integer.
*/
static inline uint8_t nla_get_u8(struct nlattr *nla)
{
return *(uint8_t *) nla_data(nla);
}
/**
* Add 16 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value to store as payload.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_u16(struct nl_msg *msg, int attrtype, uint16_t value)
{
return nla_put(msg, attrtype, sizeof(uint16_t), &value);
}
/**
* Return payload of 16 bit integer attribute.
* @arg nla 16 bit integer attribute
*
* @return Payload as 16 bit integer.
*/
static inline uint16_t nla_get_u16(struct nlattr *nla)
{
return *(uint16_t *) nla_data(nla);
}
/**
* Add 32 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value to store as payload.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value)
{
return nla_put(msg, attrtype, sizeof(uint32_t), &value);
}
/**
* Return payload of 32 bit integer attribute.
* @arg nla 32 bit integer attribute.
*
* @return Payload as 32 bit integer.
*/
static inline uint32_t nla_get_u32(struct nlattr *nla)
{
return *(uint32_t *) nla_data(nla);
}
/**
* Add 64 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value to store as payload.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_u64(struct nl_msg *msg, int attrtype, uint64_t value)
{
return nla_put(msg, attrtype, sizeof(uint64_t), &value);
}
/**
* Return payload of u64 attribute
* @arg nla u64 netlink attribute
*
* @return Payload as 64 bit integer.
*/
static inline uint64_t nla_get_u64(struct nlattr *nla)
{
uint64_t tmp;
nla_memcpy(&tmp, nla, sizeof(tmp));
return tmp;
}
/**
* Add string attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg str NUL terminated string.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_string(struct nl_msg *msg, int attrtype, const char *str)
{
return nla_put(msg, attrtype, strlen(str) + 1, str);
}
/**
* Return payload of string attribute.
* @arg nla String attribute.
*
* @return Pointer to attribute payload.
*/
static inline char *nla_get_string(struct nlattr *nla)
{
return (char *) nla_data(nla);
}
static inline char *nla_strdup(struct nlattr *nla)
{
return strdup(nla_get_string(nla));
}
/** @} */
/**
* @name Flag Attribute
*/
/**
* Add flag netlink attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_flag(struct nl_msg *msg, int attrtype)
{
return nla_put(msg, attrtype, 0, NULL);
}
/**
* Return true if flag attribute is set.
* @arg nla Flag netlink attribute.
*
* @return True if flag is set, otherwise false.
*/
static inline int nla_get_flag(struct nlattr *nla)
{
return !!nla;
}
/** @} */
/**
* @name Microseconds Attribute
*/
/**
* Add a msecs netlink attribute to a netlink message
* @arg n netlink message
* @arg attrtype attribute type
* @arg msecs number of msecs
*/
static inline int nla_put_msecs(struct nl_msg *n, int attrtype, unsigned long msecs)
{
return nla_put_u64(n, attrtype, msecs);
}
/**
* Return payload of msecs attribute
* @arg nla msecs netlink attribute
*
* @return the number of milliseconds.
*/
static inline unsigned long nla_get_msecs(struct nlattr *nla)
{
return nla_get_u64(nla);
}
/**
* Add nested attributes to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg nested Message containing attributes to be nested.
*
* Takes the attributes found in the \a nested message and appends them
* to the message \a msg nested in a container of the type \a attrtype.
* The \a nested message may not have a family specific header.
*
* @see nla_put
* @return 0 on success or a negative error code.
*/
static inline int nla_put_nested(struct nl_msg *msg, int attrtype, struct nl_msg *nested)
{
return nla_put(msg, attrtype, nlmsg_len(nested->nm_nlh),
nlmsg_data(nested->nm_nlh));
}
/**
* Start a new level of nested attributes.
* @arg msg Netlink message.
* @arg attrtype Attribute type of container.
*
* @return Pointer to container attribute.
*/
static inline struct nlattr *nla_nest_start(struct nl_msg *msg, int attrtype)
{
struct nlattr *start = (struct nlattr *) nlmsg_tail(msg->nm_nlh);
if (nla_put(msg, attrtype, 0, NULL) < 0)
return NULL;
return start;
}
/**
* Finalize nesting of attributes.
* @arg msg Netlink message.
* @arg start Container attribute as returned from nla_nest_start().
*
* Corrects the container attribute header to include the appeneded attributes.
*
* @return 0
*/
static inline int nla_nest_end(struct nl_msg *msg, struct nlattr *start)
{
start->nla_len = (unsigned char *) nlmsg_tail(msg->nm_nlh) -
(unsigned char *) start;
return 0;
}
/**
* Create attribute index based on nested attribute
* @arg tb Index array to be filled (maxtype+1 elements).
* @arg maxtype Maximum attribute type expected and accepted.
* @arg nla Nested Attribute.
* @arg policy Attribute validation policy.
*
* Feeds the stream of attributes nested into the specified attribute
* to nla_parse().
*
* @see nla_parse
* @return 0 on success or a negative error code.
*/
static inline int nla_parse_nested(struct nlattr *tb[], int maxtype, struct nlattr *nla,
struct nla_policy *policy)
{
return nla_parse(tb, maxtype, (struct nlattr *)nla_data(nla), nla_len(nla), policy);
}
/**
* Compare attribute payload with memory area.
* @arg nla Attribute.
* @arg data Memory area to compare to.
* @arg size Number of bytes to compare.
*
* @see memcmp(3)
* @return An integer less than, equal to, or greater than zero.
*/
static inline int nla_memcmp(const struct nlattr *nla, const void *data, size_t size)
{
int d = nla_len(nla) - size;
if (d == 0)
d = memcmp(nla_data(nla), data, size);
return d;
}
/**
* Compare string attribute payload with string
* @arg nla Attribute of type NLA_STRING.
* @arg str NUL terminated string.
*
* @see strcmp(3)
* @return An integer less than, equal to, or greater than zero.
*/
static inline int nla_strcmp(const struct nlattr *nla, const char *str)
{
int len = strlen(str) + 1;
int d = nla_len(nla) - len;
if (d == 0)
d = memcmp(nla_data(nla), str, len);
return d;
}
/**
* Copy string attribute payload to a buffer.
* @arg dst Pointer to destination buffer.
* @arg nla Attribute of type NLA_STRING.
* @arg dstsize Size of destination buffer in bytes.
*
* Copies at most dstsize - 1 bytes to the destination buffer.
* The result is always a valid NUL terminated string. Unlike
* strlcpy the destination buffer is always padded out.
*
* @return The length of string attribute without the terminating NUL.
*/
static inline size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
{
size_t srclen = (size_t)nla_len(nla);
char *src = (char*)nla_data(nla);
if (srclen > 0 && src[srclen - 1] == '\0')
srclen--;
if (dstsize > 0) {
size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
memset(dst, 0, dstsize);
memcpy(dst, src, len);
}
return srclen;
}
/**
* @name Attribute Construction (Exception Based)
* @{
*/
/**
* @ingroup attr
* Add unspecific attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg attrlen Length of attribute payload.
* @arg data Head of attribute payload.
*/
#define NLA_PUT(msg, attrtype, attrlen, data) \
do { \
if (nla_put(msg, attrtype, attrlen, data) < 0) \
goto nla_put_failure; \
} while(0)
/**
* @ingroup attr
* Add atomic type attribute to netlink message.
* @arg msg Netlink message.
* @arg type Atomic type.
* @arg attrtype Attribute type.
* @arg value Head of attribute payload.
*/
#define NLA_PUT_TYPE(msg, type, attrtype, value) \
do { \
type __tmp = value; \
NLA_PUT(msg, attrtype, sizeof(type), &__tmp); \
} while(0)
/**
* Add 8 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value.
*/
#define NLA_PUT_U8(msg, attrtype, value) \
NLA_PUT_TYPE(msg, uint8_t, attrtype, value)
/**
* Add 16 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value.
*/
#define NLA_PUT_U16(msg, attrtype, value) \
NLA_PUT_TYPE(msg, uint16_t, attrtype, value)
/**
* Add 32 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value.
*/
#define NLA_PUT_U32(msg, attrtype, value) \
NLA_PUT_TYPE(msg, uint32_t, attrtype, value)
/**
* Add 64 bit integer attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value Numeric value.
*/
#define NLA_PUT_U64(msg, attrtype, value) \
NLA_PUT_TYPE(msg, uint64_t, attrtype, value)
/**
* Add string attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg value NUL terminated character string.
*/
#define NLA_PUT_STRING(msg, attrtype, value) \
NLA_PUT(msg, attrtype, strlen(value) + 1, value)
/**
* Add flag attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
*/
#define NLA_PUT_FLAG(msg, attrtype) \
NLA_PUT(msg, attrtype, 0, NULL)
/**
* Add msecs attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg msecs Numeric value in micro seconds.
*/
#define NLA_PUT_MSECS(msg, attrtype, msecs) \
NLA_PUT_U64(msg, attrtype, msecs)
/**
* Add address attribute to netlink message.
* @arg msg Netlink message.
* @arg attrtype Attribute type.
* @arg addr Abstract address object.
*/
#define NLA_PUT_ADDR(msg, attrtype, addr) \
NLA_PUT(msg, attrtype, nl_addr_get_len(addr), \
nl_addr_get_binary_addr(addr))
/** @} */
/**
* @name Iterators
* @{
*/
/**
* @ingroup attr
* Iterate over a stream of attributes
* @arg pos loop counter, set to current attribute
* @arg head head of attribute stream
* @arg len length of attribute stream
* @arg rem initialized to len, holds bytes currently remaining in stream
*/
#define nla_for_each_attr(pos, head, len, rem) \
for (pos = head, rem = len; \
nla_ok(pos, rem); \
pos = nla_next(pos, &(rem)))
/**
* @ingroup attr
* Iterate over a stream of nested attributes
* @arg pos loop counter, set to current attribute
* @arg nla attribute containing the nested attributes
* @arg rem initialized to len, holds bytes currently remaining in stream
*/
#define nla_for_each_nested(pos, nla, rem) \
for (pos = (struct nlattr *)nla_data(nla), rem = nla_len(nla); \
nla_ok(pos, rem); \
pos = nla_next(pos, &(rem)))
/** @} */
#ifdef __cplusplus
}
#endif
#endif