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