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sys/netlink/netlink_message_parser.h
- This file was added.
/*- | |||||
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD | |||||
* | |||||
* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> | |||||
* | |||||
* Redistribution and use in source and binary forms, with or without | |||||
* modification, are permitted provided that the following conditions | |||||
* are met: | |||||
* 1. Redistributions of source code must retain the above copyright | |||||
* notice, this list of conditions and the following disclaimer. | |||||
* 2. Redistributions in binary form must reproduce the above copyright | |||||
* notice, this list of conditions and the following disclaimer in the | |||||
* documentation and/or other materials provided with the distribution. | |||||
* | |||||
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |||||
* SUCH DAMAGE. | |||||
*/ | |||||
#ifndef _NETLINK_NETLINK_MESSAGE_PARSER_H_ | |||||
#define _NETLINK_NETLINK_MESSAGE_PARSER_H_ | |||||
/* | |||||
* It is not meant to be included directly | |||||
*/ | |||||
/* Parsing state */ | |||||
struct linear_buffer { | |||||
char *base; /* Base allocated memory pointer */ | |||||
uint32_t offset; /* Currently used offset */ | |||||
uint32_t size; /* Total buffer size */ | |||||
}; | |||||
static inline void * | |||||
lb_alloc(struct linear_buffer *lb, int len) | |||||
{ | |||||
len = roundup2(len, sizeof(uint64_t)); | |||||
if (lb->offset + len > lb->size) | |||||
return (NULL); | |||||
void *data = (void *)(lb->base + lb->offset); | |||||
lb->offset += len; | |||||
return (data); | |||||
} | |||||
static inline void | |||||
lb_clear(struct linear_buffer *lb) | |||||
{ | |||||
memset(lb->base, 0, lb->size); | |||||
lb->offset = 0; | |||||
} | |||||
#define NL_MAX_ERROR_BUF 128 | |||||
#define SCRATCH_BUFFER_SIZE (1024 + NL_MAX_ERROR_BUF) | |||||
struct nl_pstate { | |||||
struct linear_buffer lb; /* Per-message scratch buffer */ | |||||
struct nlpcb *nlp; /* Originator socket */ | |||||
struct nl_writer *nw; /* Message writer to use */ | |||||
struct nlmsghdr *hdr; /* Current parsed message header */ | |||||
uint32_t err_off; /* error offset from hdr start */ | |||||
int error; /* last operation error */ | |||||
char *err_msg; /* Description of last error */ | |||||
bool strict; /* Strict parsing required */ | |||||
}; | |||||
static inline void * | |||||
npt_alloc(struct nl_pstate *npt, int len) | |||||
{ | |||||
return (lb_alloc(&npt->lb, len)); | |||||
} | |||||
#define npt_alloc_sockaddr(_npt, _len) ((struct sockaddr *)(npt_alloc(_npt, _len))) | |||||
typedef int parse_field_f(void *hdr, struct nl_pstate *npt, | |||||
void *target); | |||||
struct nlfield_parser { | |||||
uint16_t off_in; | |||||
uint16_t off_out; | |||||
parse_field_f *cb; | |||||
}; | |||||
static const struct nlfield_parser nlf_p_empty[] = {}; | |||||
int nlf_get_ifp(void *src, struct nl_pstate *npt, void *target); | |||||
int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target); | |||||
int nlf_get_u8(void *src, struct nl_pstate *npt, void *target); | |||||
int nlf_get_u16(void *src, struct nl_pstate *npt, void *target); | |||||
int nlf_get_u32(void *src, struct nl_pstate *npt, void *target); | |||||
int nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target); | |||||
struct nlattr_parser; | |||||
typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
struct nlattr_parser { | |||||
uint16_t type; /* Attribute type */ | |||||
uint16_t off; /* field offset in the target structure */ | |||||
parse_attr_f *cb; /* parser function to call */ | |||||
const void *arg; | |||||
}; | |||||
typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt); | |||||
struct nlhdr_parser { | |||||
int nl_hdr_off; /* aligned netlink header size */ | |||||
int out_hdr_off; /* target header size */ | |||||
int fp_size; | |||||
int np_size; | |||||
const struct nlfield_parser *fp; /* array of header field parsers */ | |||||
const struct nlattr_parser *np; /* array of attribute parsers */ | |||||
strict_parser_f *sp; /* Parser function */ | |||||
}; | |||||
#define NL_DECLARE_PARSER(_name, _t, _fp, _np) \ | |||||
static const struct nlhdr_parser _name = { \ | |||||
.nl_hdr_off = sizeof(_t), \ | |||||
.fp = &((_fp)[0]), \ | |||||
.np = &((_np)[0]), \ | |||||
.fp_size = NL_ARRAY_LEN(_fp), \ | |||||
.np_size = NL_ARRAY_LEN(_np), \ | |||||
} | |||||
#define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np)\ | |||||
static const struct nlhdr_parser _name = { \ | |||||
.nl_hdr_off = sizeof(_t), \ | |||||
.fp = &((_fp)[0]), \ | |||||
.np = &((_np)[0]), \ | |||||
.fp_size = NL_ARRAY_LEN(_fp), \ | |||||
.np_size = NL_ARRAY_LEN(_np), \ | |||||
.sp = _sp, \ | |||||
} | |||||
#define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \ | |||||
static const struct nlhdr_parser _name = { \ | |||||
.nl_hdr_off = sizeof(_t), \ | |||||
.out_hdr_off = sizeof(_o), \ | |||||
.fp = &((_fp)[0]), \ | |||||
.np = &((_np)[0]), \ | |||||
.fp_size = NL_ARRAY_LEN(_fp), \ | |||||
.np_size = NL_ARRAY_LEN(_np), \ | |||||
} | |||||
#define NL_DECLARE_ATTR_PARSER(_name, _np) \ | |||||
static const struct nlhdr_parser _name = { \ | |||||
.np = &((_np)[0]), \ | |||||
.np_size = NL_ARRAY_LEN(_np), \ | |||||
} | |||||
struct nlarr_hdr { | |||||
int num_items; | |||||
int max_items; | |||||
}; | |||||
int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, | |||||
int pslen, struct nl_pstate *npt, void *target); | |||||
int nl_parse_attrs(struct nlmsghdr *hdr, int hdrlen, struct nlattr_parser *ps, | |||||
int pslen, struct nl_pstate *npt, void *target); | |||||
int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, | |||||
const void *arg, void *target); | |||||
bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...); | |||||
#define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \ | |||||
nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \ | |||||
NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \ | |||||
} | |||||
bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off); | |||||
/* | |||||
* Have it inline so compiler can optimize field accesses into | |||||
* the list of direct function calls without iteration. | |||||
*/ | |||||
static inline int | |||||
nl_parse_header(void *hdr, int len, const struct nlhdr_parser *parser, | |||||
struct nl_pstate *npt, void *target) | |||||
{ | |||||
int error; | |||||
if (__predict_false(len < parser->nl_hdr_off)) { | |||||
nlmsg_report_err_msg(npt, "header too short: expected %d, got %d", | |||||
parser->nl_hdr_off, len); | |||||
return (EINVAL); | |||||
} | |||||
if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt)) | |||||
return (EINVAL); | |||||
/* Extract fields first */ | |||||
for (int i = 0; i < parser->fp_size; i++) { | |||||
const struct nlfield_parser *fp = &parser->fp[i]; | |||||
void *src = (char *)hdr + fp->off_in; | |||||
void *dst = (char *)target + fp->off_out; | |||||
error = fp->cb(src, npt, dst); | |||||
if (error != 0) | |||||
return (error); | |||||
} | |||||
struct nlattr *nla_head = (struct nlattr *)((char *)hdr + parser->nl_hdr_off); | |||||
error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np, | |||||
parser->np_size, npt, target); | |||||
return (error); | |||||
} | |||||
static inline int | |||||
nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser, | |||||
struct nl_pstate *npt, void *target) | |||||
{ | |||||
struct nlattr *nla_head = (struct nlattr *)NLA_DATA(nla); | |||||
return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np, | |||||
parser->np_size, npt, target)); | |||||
} | |||||
/* | |||||
* Checks that attributes are sorted by attribute type. | |||||
*/ | |||||
static inline void | |||||
nl_verify_parsers(const struct nlhdr_parser **parser, int count) | |||||
{ | |||||
for (int i = 0; i < count; i++) { | |||||
const struct nlhdr_parser *p = parser[i]; | |||||
int attr_type = 0; | |||||
for (int j = 0; j < p->np_size; j++) { | |||||
MPASS(p->np[j].type > attr_type); | |||||
attr_type = p->np[j].type; | |||||
} | |||||
} | |||||
} | |||||
void nl_verify_parsers(const struct nlhdr_parser **parser, int count); | |||||
#define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), NL_ARRAY_LEN(_p)) | |||||
static inline int | |||||
nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, | |||||
struct nl_pstate *npt, void *target) | |||||
{ | |||||
return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target)); | |||||
} | |||||
#endif |