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1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */2 3/*4 * NETLINK Netlink attributes5 *6 * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>7 */8 9#ifndef __LIBBPF_NLATTR_H10#define __LIBBPF_NLATTR_H11 12#include <stdint.h>13#include <string.h>14#include <errno.h>15#include <linux/netlink.h>16#include <linux/rtnetlink.h>17#include <linux/genetlink.h>18 19/* avoid multiple definition of netlink features */20#define __LINUX_NETLINK_H21 22/**23 * Standard attribute types to specify validation policy24 */25enum {26 LIBBPF_NLA_UNSPEC, /**< Unspecified type, binary data chunk */27 LIBBPF_NLA_U8, /**< 8 bit integer */28 LIBBPF_NLA_U16, /**< 16 bit integer */29 LIBBPF_NLA_U32, /**< 32 bit integer */30 LIBBPF_NLA_U64, /**< 64 bit integer */31 LIBBPF_NLA_STRING, /**< NUL terminated character string */32 LIBBPF_NLA_FLAG, /**< Flag */33 LIBBPF_NLA_MSECS, /**< Micro seconds (64bit) */34 LIBBPF_NLA_NESTED, /**< Nested attributes */35 __LIBBPF_NLA_TYPE_MAX,36};37 38#define LIBBPF_NLA_TYPE_MAX (__LIBBPF_NLA_TYPE_MAX - 1)39 40/**41 * @ingroup attr42 * Attribute validation policy.43 *44 * See section @core_doc{core_attr_parse,Attribute Parsing} for more details.45 */46struct libbpf_nla_policy {47 /** Type of attribute or LIBBPF_NLA_UNSPEC */48 uint16_t type;49 50 /** Minimal length of payload required */51 uint16_t minlen;52 53 /** Maximal length of payload allowed */54 uint16_t maxlen;55};56 57struct libbpf_nla_req {58 struct nlmsghdr nh;59 union {60 struct ifinfomsg ifinfo;61 struct tcmsg tc;62 struct genlmsghdr gnl;63 };64 char buf[128];65};66 67/**68 * @ingroup attr69 * Iterate over a stream of attributes70 * @arg pos loop counter, set to current attribute71 * @arg head head of attribute stream72 * @arg len length of attribute stream73 * @arg rem initialized to len, holds bytes currently remaining in stream74 */75#define libbpf_nla_for_each_attr(pos, head, len, rem) \76 for (pos = head, rem = len; \77 nla_ok(pos, rem); \78 pos = nla_next(pos, &(rem)))79 80/**81 * libbpf_nla_data - head of payload82 * @nla: netlink attribute83 */84static inline void *libbpf_nla_data(const struct nlattr *nla)85{86 return (void *)nla + NLA_HDRLEN;87}88 89static inline uint8_t libbpf_nla_getattr_u8(const struct nlattr *nla)90{91 return *(uint8_t *)libbpf_nla_data(nla);92}93 94static inline uint16_t libbpf_nla_getattr_u16(const struct nlattr *nla)95{96 return *(uint16_t *)libbpf_nla_data(nla);97}98 99static inline uint32_t libbpf_nla_getattr_u32(const struct nlattr *nla)100{101 return *(uint32_t *)libbpf_nla_data(nla);102}103 104static inline uint64_t libbpf_nla_getattr_u64(const struct nlattr *nla)105{106 return *(uint64_t *)libbpf_nla_data(nla);107}108 109static inline const char *libbpf_nla_getattr_str(const struct nlattr *nla)110{111 return (const char *)libbpf_nla_data(nla);112}113 114/**115 * libbpf_nla_len - length of payload116 * @nla: netlink attribute117 */118static inline int libbpf_nla_len(const struct nlattr *nla)119{120 return nla->nla_len - NLA_HDRLEN;121}122 123int libbpf_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,124 int len, struct libbpf_nla_policy *policy);125int libbpf_nla_parse_nested(struct nlattr *tb[], int maxtype,126 struct nlattr *nla,127 struct libbpf_nla_policy *policy);128 129int libbpf_nla_dump_errormsg(struct nlmsghdr *nlh);130 131static inline struct nlattr *nla_data(struct nlattr *nla)132{133 return (struct nlattr *)((void *)nla + NLA_HDRLEN);134}135 136static inline struct nlattr *req_tail(struct libbpf_nla_req *req)137{138 return (struct nlattr *)((void *)req + NLMSG_ALIGN(req->nh.nlmsg_len));139}140 141static inline int nlattr_add(struct libbpf_nla_req *req, int type,142 const void *data, int len)143{144 struct nlattr *nla;145 146 if (NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(NLA_HDRLEN + len) > sizeof(*req))147 return -EMSGSIZE;148 if (!!data != !!len)149 return -EINVAL;150 151 nla = req_tail(req);152 nla->nla_type = type;153 nla->nla_len = NLA_HDRLEN + len;154 if (data)155 memcpy(nla_data(nla), data, len);156 req->nh.nlmsg_len = NLMSG_ALIGN(req->nh.nlmsg_len) + NLA_ALIGN(nla->nla_len);157 return 0;158}159 160static inline struct nlattr *nlattr_begin_nested(struct libbpf_nla_req *req, int type)161{162 struct nlattr *tail;163 164 tail = req_tail(req);165 if (nlattr_add(req, type | NLA_F_NESTED, NULL, 0))166 return NULL;167 return tail;168}169 170static inline void nlattr_end_nested(struct libbpf_nla_req *req,171 struct nlattr *tail)172{173 tail->nla_len = (void *)req_tail(req) - (void *)tail;174}175 176#endif /* __LIBBPF_NLATTR_H */177