1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #ifndef _NETLINK_NETLINK_MESSAGE_PARSER_H_ 29 #define _NETLINK_NETLINK_MESSAGE_PARSER_H_ 30 31 #ifdef _KERNEL 32 33 #include <sys/bitset.h> 34 35 /* 36 * It is not meant to be included directly 37 */ 38 39 /* Parsing state */ 40 struct linear_buffer { 41 char *base; /* Base allocated memory pointer */ 42 uint32_t offset; /* Currently used offset */ 43 uint32_t size; /* Total buffer size */ 44 }; 45 46 static inline void * 47 lb_alloc(struct linear_buffer *lb, int len) 48 { 49 len = roundup2(len, sizeof(uint64_t)); 50 if (lb->offset + len > lb->size) 51 return (NULL); 52 void *data = (void *)(lb->base + lb->offset); 53 lb->offset += len; 54 return (data); 55 } 56 57 static inline void 58 lb_clear(struct linear_buffer *lb) 59 { 60 memset(lb->base, 0, lb->size); 61 lb->offset = 0; 62 } 63 64 #define NL_MAX_ERROR_BUF 128 65 #define SCRATCH_BUFFER_SIZE (1024 + NL_MAX_ERROR_BUF) 66 struct nl_pstate { 67 struct linear_buffer lb; /* Per-message scratch buffer */ 68 struct nlpcb *nlp; /* Originator socket */ 69 struct nl_writer *nw; /* Message writer to use */ 70 struct nlmsghdr *hdr; /* Current parsed message header */ 71 uint32_t err_off; /* error offset from hdr start */ 72 int error; /* last operation error */ 73 char *err_msg; /* Description of last error */ 74 bool strict; /* Strict parsing required */ 75 }; 76 77 static inline void * 78 npt_alloc(struct nl_pstate *npt, int len) 79 { 80 return (lb_alloc(&npt->lb, len)); 81 } 82 #define npt_alloc_sockaddr(_npt, _len) ((struct sockaddr *)(npt_alloc(_npt, _len))) 83 84 typedef int parse_field_f(void *hdr, struct nl_pstate *npt, 85 void *target); 86 struct nlfield_parser { 87 uint16_t off_in; 88 uint16_t off_out; 89 parse_field_f *cb; 90 }; 91 static const struct nlfield_parser nlf_p_empty[] = {}; 92 93 int nlf_get_ifp(void *src, struct nl_pstate *npt, void *target); 94 int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target); 95 int nlf_get_u8(void *src, struct nl_pstate *npt, void *target); 96 int nlf_get_u16(void *src, struct nl_pstate *npt, void *target); 97 int nlf_get_u32(void *src, struct nl_pstate *npt, void *target); 98 int nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target); 99 100 101 struct nlattr_parser; 102 typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt, 103 const void *arg, void *target); 104 struct nlattr_parser { 105 uint16_t type; /* Attribute type */ 106 uint16_t off; /* field offset in the target structure */ 107 parse_attr_f *cb; /* parser function to call */ 108 const void *arg; 109 }; 110 111 typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt); 112 113 struct nlhdr_parser { 114 int nl_hdr_off; /* aligned netlink header size */ 115 int out_hdr_off; /* target header size */ 116 int fp_size; 117 int np_size; 118 const struct nlfield_parser *fp; /* array of header field parsers */ 119 const struct nlattr_parser *np; /* array of attribute parsers */ 120 strict_parser_f *sp; /* Parser function */ 121 }; 122 123 #define NL_DECLARE_PARSER(_name, _t, _fp, _np) \ 124 static const struct nlhdr_parser _name = { \ 125 .nl_hdr_off = sizeof(_t), \ 126 .fp = &((_fp)[0]), \ 127 .np = &((_np)[0]), \ 128 .fp_size = NL_ARRAY_LEN(_fp), \ 129 .np_size = NL_ARRAY_LEN(_np), \ 130 } 131 132 #define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np)\ 133 static const struct nlhdr_parser _name = { \ 134 .nl_hdr_off = sizeof(_t), \ 135 .fp = &((_fp)[0]), \ 136 .np = &((_np)[0]), \ 137 .fp_size = NL_ARRAY_LEN(_fp), \ 138 .np_size = NL_ARRAY_LEN(_np), \ 139 .sp = _sp, \ 140 } 141 142 #define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \ 143 static const struct nlhdr_parser _name = { \ 144 .nl_hdr_off = sizeof(_t), \ 145 .out_hdr_off = sizeof(_o), \ 146 .fp = &((_fp)[0]), \ 147 .np = &((_np)[0]), \ 148 .fp_size = NL_ARRAY_LEN(_fp), \ 149 .np_size = NL_ARRAY_LEN(_np), \ 150 } 151 152 #define NL_DECLARE_ATTR_PARSER(_name, _np) \ 153 static const struct nlhdr_parser _name = { \ 154 .np = &((_np)[0]), \ 155 .np_size = NL_ARRAY_LEN(_np), \ 156 } 157 158 #define NL_ATTR_BMASK_SIZE 128 159 BITSET_DEFINE(nlattr_bmask, NL_ATTR_BMASK_SIZE); 160 161 void nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm); 162 bool nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type); 163 164 int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, 165 int pslen, struct nl_pstate *npt, void *target); 166 167 int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, 168 const void *arg, void *target); 169 int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, 170 const void *arg, void *target); 171 int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, 172 const void *arg, void *target); 173 int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, 174 const void *arg, void *target); 175 int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, 176 const void *arg, void *target); 177 int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, 178 const void *arg, void *target); 179 int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, 180 const void *arg, void *target); 181 int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, 182 const void *arg, void *target); 183 int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, 184 const void *arg, void *target); 185 int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, 186 const void *arg, void *target); 187 int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, 188 const void *arg, void *target); 189 int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, 190 const void *arg, void *target); 191 192 bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...); 193 194 #define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \ 195 nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \ 196 NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \ 197 } 198 199 bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off); 200 201 /* 202 * Have it inline so compiler can optimize field accesses into 203 * the list of direct function calls without iteration. 204 */ 205 static inline int 206 nl_parse_header(void *hdr, int len, const struct nlhdr_parser *parser, 207 struct nl_pstate *npt, void *target) 208 { 209 int error; 210 211 if (__predict_false(len < parser->nl_hdr_off)) { 212 if (npt->strict) { 213 nlmsg_report_err_msg(npt, "header too short: expected %d, got %d", 214 parser->nl_hdr_off, len); 215 return (EINVAL); 216 } 217 218 /* Compat with older applications: pretend there's a full header */ 219 void *tmp_hdr = npt_alloc(npt, parser->nl_hdr_off); 220 if (tmp_hdr == NULL) 221 return (EINVAL); 222 memcpy(tmp_hdr, hdr, len); 223 hdr = tmp_hdr; 224 len = parser->nl_hdr_off; 225 } 226 227 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt)) 228 return (EINVAL); 229 230 /* Extract fields first */ 231 for (int i = 0; i < parser->fp_size; i++) { 232 const struct nlfield_parser *fp = &parser->fp[i]; 233 void *src = (char *)hdr + fp->off_in; 234 void *dst = (char *)target + fp->off_out; 235 236 error = fp->cb(src, npt, dst); 237 if (error != 0) 238 return (error); 239 } 240 241 struct nlattr *nla_head = (struct nlattr *)((char *)hdr + parser->nl_hdr_off); 242 error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np, 243 parser->np_size, npt, target); 244 245 return (error); 246 } 247 248 static inline int 249 nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser, 250 struct nl_pstate *npt, void *target) 251 { 252 struct nlattr *nla_head = (struct nlattr *)NLA_DATA(nla); 253 254 return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np, 255 parser->np_size, npt, target)); 256 } 257 258 /* 259 * Checks that attributes are sorted by attribute type. 260 */ 261 static inline void 262 nl_verify_parsers(const struct nlhdr_parser **parser, int count) 263 { 264 #ifdef INVARIANTS 265 for (int i = 0; i < count; i++) { 266 const struct nlhdr_parser *p = parser[i]; 267 int attr_type = 0; 268 for (int j = 0; j < p->np_size; j++) { 269 MPASS(p->np[j].type > attr_type); 270 attr_type = p->np[j].type; 271 } 272 } 273 #endif 274 } 275 void nl_verify_parsers(const struct nlhdr_parser **parser, int count); 276 #define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), NL_ARRAY_LEN(_p)) 277 278 static inline int 279 nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, 280 struct nl_pstate *npt, void *target) 281 { 282 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target)); 283 } 284 285 static inline void 286 nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, 287 struct nlattr_bmask *bm) 288 { 289 struct nlattr *nla_head; 290 291 nla_head = (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off); 292 int len = hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off; 293 294 nl_get_attrs_bmask_raw(nla_head, len, bm); 295 } 296 297 #endif 298 #endif 299