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 struct nlattr *cookie; /* NLA to return to the userspace */ 75 bool strict; /* Strict parsing required */ 76 }; 77 78 static inline void * 79 npt_alloc(struct nl_pstate *npt, int len) 80 { 81 return (lb_alloc(&npt->lb, len)); 82 } 83 #define npt_alloc_sockaddr(_npt, _len) ((struct sockaddr *)(npt_alloc(_npt, _len))) 84 85 typedef int parse_field_f(void *hdr, struct nl_pstate *npt, 86 void *target); 87 struct nlfield_parser { 88 uint16_t off_in; 89 uint16_t off_out; 90 parse_field_f *cb; 91 }; 92 static const struct nlfield_parser nlf_p_empty[] = {}; 93 94 int nlf_get_ifp(void *src, struct nl_pstate *npt, void *target); 95 int nlf_get_ifpz(void *src, struct nl_pstate *npt, void *target); 96 int nlf_get_u8(void *src, struct nl_pstate *npt, void *target); 97 int nlf_get_u16(void *src, struct nl_pstate *npt, void *target); 98 int nlf_get_u32(void *src, struct nl_pstate *npt, void *target); 99 int nlf_get_u8_u32(void *src, struct nl_pstate *npt, void *target); 100 101 102 struct nlattr_parser; 103 typedef int parse_attr_f(struct nlattr *attr, struct nl_pstate *npt, 104 const void *arg, void *target); 105 struct nlattr_parser { 106 uint16_t type; /* Attribute type */ 107 uint16_t off; /* field offset in the target structure */ 108 parse_attr_f *cb; /* parser function to call */ 109 const void *arg; 110 }; 111 112 typedef bool strict_parser_f(void *hdr, struct nl_pstate *npt); 113 114 struct nlhdr_parser { 115 int nl_hdr_off; /* aligned netlink header size */ 116 int out_hdr_off; /* target header size */ 117 int fp_size; 118 int np_size; 119 const struct nlfield_parser *fp; /* array of header field parsers */ 120 const struct nlattr_parser *np; /* array of attribute parsers */ 121 strict_parser_f *sp; /* Parser function */ 122 }; 123 124 #define NL_DECLARE_PARSER(_name, _t, _fp, _np) \ 125 static const struct nlhdr_parser _name = { \ 126 .nl_hdr_off = sizeof(_t), \ 127 .fp = &((_fp)[0]), \ 128 .np = &((_np)[0]), \ 129 .fp_size = NL_ARRAY_LEN(_fp), \ 130 .np_size = NL_ARRAY_LEN(_np), \ 131 } 132 133 #define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np)\ 134 static const struct nlhdr_parser _name = { \ 135 .nl_hdr_off = sizeof(_t), \ 136 .fp = &((_fp)[0]), \ 137 .np = &((_np)[0]), \ 138 .fp_size = NL_ARRAY_LEN(_fp), \ 139 .np_size = NL_ARRAY_LEN(_np), \ 140 .sp = _sp, \ 141 } 142 143 #define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \ 144 static const struct nlhdr_parser _name = { \ 145 .nl_hdr_off = sizeof(_t), \ 146 .out_hdr_off = sizeof(_o), \ 147 .fp = &((_fp)[0]), \ 148 .np = &((_np)[0]), \ 149 .fp_size = NL_ARRAY_LEN(_fp), \ 150 .np_size = NL_ARRAY_LEN(_np), \ 151 } 152 153 #define NL_DECLARE_ATTR_PARSER(_name, _np) \ 154 static const struct nlhdr_parser _name = { \ 155 .np = &((_np)[0]), \ 156 .np_size = NL_ARRAY_LEN(_np), \ 157 } 158 159 #define NL_ATTR_BMASK_SIZE 128 160 BITSET_DEFINE(nlattr_bmask, NL_ATTR_BMASK_SIZE); 161 162 void nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm); 163 bool nl_has_attr(const struct nlattr_bmask *bm, unsigned int nla_type); 164 165 int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps, 166 int pslen, struct nl_pstate *npt, void *target); 167 168 int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, 169 const void *arg, void *target); 170 int nlattr_get_ip(struct nlattr *nla, struct nl_pstate *npt, 171 const void *arg, void *target); 172 int nlattr_get_uint16(struct nlattr *nla, struct nl_pstate *npt, 173 const void *arg, void *target); 174 int nlattr_get_uint32(struct nlattr *nla, struct nl_pstate *npt, 175 const void *arg, void *target); 176 int nlattr_get_uint64(struct nlattr *nla, struct nl_pstate *npt, 177 const void *arg, void *target); 178 int nlattr_get_ifp(struct nlattr *nla, struct nl_pstate *npt, 179 const void *arg, void *target); 180 int nlattr_get_ifpz(struct nlattr *nla, struct nl_pstate *npt, 181 const void *arg, void *target); 182 int nlattr_get_ipvia(struct nlattr *nla, struct nl_pstate *npt, 183 const void *arg, void *target); 184 int nlattr_get_string(struct nlattr *nla, struct nl_pstate *npt, 185 const void *arg, void *target); 186 int nlattr_get_stringn(struct nlattr *nla, struct nl_pstate *npt, 187 const void *arg, void *target); 188 int nlattr_get_nla(struct nlattr *nla, struct nl_pstate *npt, 189 const void *arg, void *target); 190 int nlattr_get_nested(struct nlattr *nla, struct nl_pstate *npt, 191 const void *arg, void *target); 192 193 bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...); 194 195 #define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \ 196 nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \ 197 NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \ 198 } 199 200 bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off); 201 202 void nlmsg_report_cookie(struct nl_pstate *npt, struct nlattr *nla); 203 void nlmsg_report_cookie_u32(struct nl_pstate *npt, uint32_t val); 204 205 /* 206 * Have it inline so compiler can optimize field accesses into 207 * the list of direct function calls without iteration. 208 */ 209 static inline int 210 nl_parse_header(void *hdr, int len, const struct nlhdr_parser *parser, 211 struct nl_pstate *npt, void *target) 212 { 213 int error; 214 215 if (__predict_false(len < parser->nl_hdr_off)) { 216 if (npt->strict) { 217 nlmsg_report_err_msg(npt, "header too short: expected %d, got %d", 218 parser->nl_hdr_off, len); 219 return (EINVAL); 220 } 221 222 /* Compat with older applications: pretend there's a full header */ 223 void *tmp_hdr = npt_alloc(npt, parser->nl_hdr_off); 224 if (tmp_hdr == NULL) 225 return (EINVAL); 226 memcpy(tmp_hdr, hdr, len); 227 hdr = tmp_hdr; 228 len = parser->nl_hdr_off; 229 } 230 231 if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt)) 232 return (EINVAL); 233 234 /* Extract fields first */ 235 for (int i = 0; i < parser->fp_size; i++) { 236 const struct nlfield_parser *fp = &parser->fp[i]; 237 void *src = (char *)hdr + fp->off_in; 238 void *dst = (char *)target + fp->off_out; 239 240 error = fp->cb(src, npt, dst); 241 if (error != 0) 242 return (error); 243 } 244 245 struct nlattr *nla_head = (struct nlattr *)((char *)hdr + parser->nl_hdr_off); 246 error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np, 247 parser->np_size, npt, target); 248 249 return (error); 250 } 251 252 static inline int 253 nl_parse_nested(struct nlattr *nla, const struct nlhdr_parser *parser, 254 struct nl_pstate *npt, void *target) 255 { 256 struct nlattr *nla_head = (struct nlattr *)NLA_DATA(nla); 257 258 return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np, 259 parser->np_size, npt, target)); 260 } 261 262 /* 263 * Checks that attributes are sorted by attribute type. 264 */ 265 static inline void 266 nl_verify_parsers(const struct nlhdr_parser **parser, int count) 267 { 268 #ifdef INVARIANTS 269 for (int i = 0; i < count; i++) { 270 const struct nlhdr_parser *p = parser[i]; 271 int attr_type = 0; 272 for (int j = 0; j < p->np_size; j++) { 273 MPASS(p->np[j].type > attr_type); 274 attr_type = p->np[j].type; 275 } 276 } 277 #endif 278 } 279 void nl_verify_parsers(const struct nlhdr_parser **parser, int count); 280 #define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), NL_ARRAY_LEN(_p)) 281 282 static inline int 283 nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, 284 struct nl_pstate *npt, void *target) 285 { 286 return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target)); 287 } 288 289 static inline void 290 nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser, 291 struct nlattr_bmask *bm) 292 { 293 struct nlattr *nla_head; 294 295 nla_head = (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off); 296 int len = hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off; 297 298 nl_get_attrs_bmask_raw(nla_head, len, bm); 299 } 300 301 #endif 302 #endif 303