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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/*
* NETLINK Netlink attributes
*
* Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
*/
#ifndef __LIBBPF_NLATTR_H
#define __LIBBPF_NLATTR_H
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
/* avoid multiple definition of netlink features */
#define __LINUX_NETLINK_H
/**
* Standard attribute types to specify validation policy
*/
enum {
LIBBPF_NLA_UNSPEC, /**< Unspecified type, binary data chunk */
LIBBPF_NLA_U8, /**< 8 bit integer */
LIBBPF_NLA_U16, /**< 16 bit integer */
LIBBPF_NLA_U32, /**< 32 bit integer */
LIBBPF_NLA_U64, /**< 64 bit integer */
LIBBPF_NLA_STRING, /**< NUL terminated character string */
LIBBPF_NLA_FLAG, /**< Flag */
LIBBPF_NLA_MSECS, /**< Micro seconds (64bit) */
LIBBPF_NLA_NESTED, /**< Nested attributes */
__LIBBPF_NLA_TYPE_MAX,
};
#define LIBBPF_NLA_TYPE_MAX (__LIBBPF_NLA_TYPE_MAX - 1)
/**
* @ingroup attr
* Attribute validation policy.
*
* See section @core_doc{core_attr_parse,Attribute Parsing} for more details.
*/
struct libbpf_nla_policy {
/** Type of attribute or LIBBPF_NLA_UNSPEC */
uint16_t type;
/** Minimal length of payload required */
uint16_t minlen;
/** Maximal length of payload allowed */
uint16_t maxlen;
};
struct libbpf_nla_req {
struct nlmsghdr nh;
union {
struct ifinfomsg ifinfo;
struct tcmsg tc;
};
char buf[128];
};
/**
* @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 libbpf_nla_for_each_attr(pos, head, len, rem) \
for (pos = head, rem = len; \
nla_ok(pos, rem); \
pos = nla_next(pos, &(rem)))
/**
* libbpf_nla_data - head of payload
* @nla: netlink attribute
*/
static inline void *libbpf_nla_data(const struct nlattr *nla)
{
return (void *)nla + NLA_HDRLEN;
}
static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)
{
return *(uint8_t *)libbpf_nla_data(nla);
}
static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)
{
return *(uint32_t *)libbpf_nla_data(nla);
}
static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla)
{
return (const char *)libbpf_nla_data(nla);
}
/**
* libbpf_nla_len - length of payload
* @nla: netlink attribute
*/
static inline int libbpf_nla_len(const struct nlattr *nla)
{
return nla->nla_len - NLA_HDRLEN;
}
int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
int len, struct libbpf_nla_policy *policy);
int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,
struct nlattr *nla,
struct libbpf_nla_policy *policy);
int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh);
static inline struct nlattr *nla_data(struct nlattr *nla)
{
return (struct nlattr *)((void *)nla + NLA_HDRLEN);
}
static inline struct nlattr *req_tail(struct libbpf_nla_req *req)
{
return (struct nlattr *)((void *)req + NLMSG_ALIGN(req->nh.nlmsg_len));
}
static inline int nlattr_add(struct libbpf_nla_req *req, int type,
const void *data, int len)
{
struct nlattr *nla;
if (NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(NLA_HDRLEN + len) > sizeof(*req))
return -EMSGSIZE;
if (!!data != !!len)
return -EINVAL;
nla = req_tail(req);
nla->nla_type = type;
nla->nla_len = NLA_HDRLEN + len;
if (data)
memcpy(nla_data(nla), data, len);
req->nh.nlmsg_len = NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(nla->nla_len);
return 0;
}
static inline struct nlattr *nlattr_begin_nested(struct libbpf_nla_req *req, int type)
{
struct nlattr *tail;
tail = req_tail(req);
if (nlattr_add(req, type | NLA_F_NESTED, NULL, 0))
return NULL;
return tail;
}
static inline void nlattr_end_nested(struct libbpf_nla_req *req,
struct nlattr *tail)
{
tail->nla_len = (void *)req_tail(req) - (void *)tail;
}
#endif /* __LIBBPF_NLATTR_H */
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