2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
27 #ifndef _NETLINK_NETLINK_SNL_H_
28 #define _NETLINK_NETLINK_SNL_H_
31 * Simple Netlink Library
43 #include <sys/types.h>
44 #include <sys/socket.h>
45 #include <netlink/netlink.h>
47 #define _roundup2(x, y) (((x)+((y)-1))&(~((y)-1)))
49 #define NETLINK_ALIGN_SIZE sizeof(uint32_t)
50 #define NETLINK_ALIGN(_len) _roundup2(_len, NETLINK_ALIGN_SIZE)
52 #define NLA_ALIGN_SIZE sizeof(uint32_t)
53 #define NLA_HDRLEN ((int)sizeof(struct nlattr))
54 #define NLA_DATA_LEN(_nla) ((int)((_nla)->nla_len - NLA_HDRLEN))
55 #define NLA_DATA(_nla) NL_ITEM_DATA(_nla, NLA_HDRLEN)
56 #define NLA_DATA_CONST(_nla) NL_ITEM_DATA_CONST(_nla, NLA_HDRLEN)
58 #define NLA_TYPE(_nla) ((_nla)->nla_type & 0x3FFF)
60 #define NLA_NEXT(_attr) (struct nlattr *)(void *)((char *)_attr + NLA_ALIGN(_attr->nla_len))
62 #define _NLA_END(_start, _len) ((char *)(_start) + (_len))
63 #define NLA_FOREACH(_attr, _start, _len) \
64 for (_attr = (_start); \
65 ((char *)_attr < _NLA_END(_start, _len)) && \
66 ((char *)NLA_NEXT(_attr) <= _NLA_END(_start, _len)); \
67 _attr = NLA_NEXT(_attr))
69 #define NL_ARRAY_LEN(_a) (sizeof(_a) / sizeof((_a)[0]))
71 struct linear_buffer {
72 char *base; /* Base allocated memory pointer */
73 uint32_t offset; /* Currently used offset */
74 uint32_t size; /* Total buffer size */
75 struct linear_buffer *next; /* Buffer chaining */
78 static inline struct linear_buffer *
79 lb_init(uint32_t size)
81 struct linear_buffer *lb = calloc(1, size);
84 lb->base = (char *)(lb + 1);
85 lb->size = size - sizeof(*lb);
92 lb_free(struct linear_buffer *lb)
98 lb_allocz(struct linear_buffer *lb, int len)
100 len = roundup2(len, sizeof(uint64_t));
101 if (lb->offset + len > lb->size)
103 void *data = (void *)(lb->base + lb->offset);
109 lb_clear(struct linear_buffer *lb)
111 memset(lb->base, 0, lb->offset);
123 struct linear_buffer *lb;
125 #define SCRATCH_BUFFER_SIZE 1024
126 #define SNL_WRITER_BUFFER_SIZE 256
128 typedef void snl_parse_field_f(struct snl_state *ss, void *hdr, void *target);
129 struct snl_field_parser {
132 snl_parse_field_f *cb;
135 typedef bool snl_parse_attr_f(struct snl_state *ss, struct nlattr *attr,
136 const void *arg, void *target);
137 struct snl_attr_parser {
138 uint16_t type; /* Attribute type */
139 uint16_t off; /* field offset in the target structure */
140 snl_parse_attr_f *cb; /* parser function to call */
141 const void *arg; /* Optional argument parser */
144 struct snl_hdr_parser {
145 int hdr_off; /* aligned header size */
148 const struct snl_field_parser *fp; /* array of header field parsers */
149 const struct snl_attr_parser *np; /* array of attribute parsers */
152 #define SNL_DECLARE_PARSER(_name, _t, _fp, _np) \
153 static const struct snl_hdr_parser _name = { \
154 .hdr_off = sizeof(_t), \
157 .fp_size = NL_ARRAY_LEN(_fp), \
158 .np_size = NL_ARRAY_LEN(_np), \
161 #define SNL_DECLARE_ATTR_PARSER(_name, _np) \
162 static const struct snl_hdr_parser _name = { \
164 .np_size = NL_ARRAY_LEN(_np), \
169 snl_allocz(struct snl_state *ss, int len)
171 void *data = lb_allocz(ss->lb, len);
174 uint32_t size = ss->lb->size * 2;
176 while (size < len + sizeof(struct linear_buffer))
179 struct linear_buffer *lb = lb_init(size);
184 data = lb_allocz(ss->lb, len);
192 snl_clear_lb(struct snl_state *ss)
194 struct linear_buffer *lb = ss->lb;
199 /* Remove all linear bufs except the largest one */
201 struct linear_buffer *lb_next = lb->next;
208 snl_free(struct snl_state *ss)
214 if (ss->lb != NULL) {
222 snl_init(struct snl_state *ss, int netlink_family)
224 memset(ss, 0, sizeof(*ss));
226 ss->fd = socket(AF_NETLINK, SOCK_RAW, netlink_family);
229 ss->init_done = true;
232 socklen_t optlen = sizeof(rcvbuf);
233 if (getsockopt(ss->fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &optlen) == -1) {
238 ss->bufsize = rcvbuf;
239 ss->buf = malloc(ss->bufsize);
240 if (ss->buf == NULL) {
245 ss->lb = lb_init(SCRATCH_BUFFER_SIZE);
246 if (ss->lb == NULL) {
255 snl_send(struct snl_state *ss, void *data, int sz)
257 return (send(ss->fd, data, sz, 0) == sz);
261 snl_send_message(struct snl_state *ss, struct nlmsghdr *hdr)
263 ssize_t sz = NLMSG_ALIGN(hdr->nlmsg_len);
265 return (send(ss->fd, hdr, sz, 0) == sz);
268 static inline uint32_t
269 snl_get_seq(struct snl_state *ss)
274 static inline struct nlmsghdr *
275 snl_read_message(struct snl_state *ss)
277 if (ss->off == ss->datalen) {
278 struct sockaddr_nl nladdr;
281 .iov_len = ss->bufsize,
283 struct msghdr msg = {
285 .msg_namelen = sizeof(nladdr),
292 ssize_t datalen = recvmsg(ss->fd, &msg, 0);
294 ss->datalen = datalen;
296 } else if (errno != EINTR)
300 struct nlmsghdr *hdr = (struct nlmsghdr *)(void *)&ss->buf[ss->off];
301 ss->off += NLMSG_ALIGN(hdr->nlmsg_len);
305 static inline struct nlmsghdr *
306 snl_read_reply(struct snl_state *ss, uint32_t nlmsg_seq)
308 struct nlmsghdr *hdr;
310 while ((hdr = snl_read_message(ss)) != NULL) {
311 if (hdr->nlmsg_seq == nlmsg_seq)
319 * Checks that attributes are sorted by attribute type.
322 snl_verify_parsers(const struct snl_hdr_parser **parser, int count)
324 for (int i = 0; i < count; i++) {
325 const struct snl_hdr_parser *p = parser[i];
327 for (int j = 0; j < p->np_size; j++) {
328 assert(p->np[j].type > attr_type);
329 attr_type = p->np[j].type;
333 #define SNL_VERIFY_PARSERS(_p) snl_verify_parsers((_p), NL_ARRAY_LEN(_p))
335 static const struct snl_attr_parser *
336 find_parser(const struct snl_attr_parser *ps, int pslen, int key)
338 int left_i = 0, right_i = pslen - 1;
340 if (key < ps[0].type || key > ps[pslen - 1].type)
343 while (left_i + 1 < right_i) {
344 int mid_i = (left_i + right_i) / 2;
345 if (key < ps[mid_i].type)
347 else if (key > ps[mid_i].type)
352 if (ps[left_i].type == key)
353 return (&ps[left_i]);
354 else if (ps[right_i].type == key)
355 return (&ps[right_i]);
360 snl_parse_attrs_raw(struct snl_state *ss, struct nlattr *nla_head, int len,
361 const struct snl_attr_parser *ps, int pslen, void *target)
365 NLA_FOREACH(nla, nla_head, len) {
366 if (nla->nla_len < sizeof(struct nlattr))
368 int nla_type = nla->nla_type & NLA_TYPE_MASK;
369 const struct snl_attr_parser *s = find_parser(ps, pslen, nla_type);
371 void *ptr = (void *)((char *)target + s->off);
372 if (!s->cb(ss, nla, s->arg, ptr))
380 snl_parse_attrs(struct snl_state *ss, struct nlmsghdr *hdr, int hdrlen,
381 const struct snl_attr_parser *ps, int pslen, void *target)
383 int off = NLMSG_HDRLEN + NETLINK_ALIGN(hdrlen);
384 int len = hdr->nlmsg_len - off;
385 struct nlattr *nla_head = (struct nlattr *)(void *)((char *)hdr + off);
387 return (snl_parse_attrs_raw(ss, nla_head, len, ps, pslen, target));
391 snl_parse_fields(struct snl_state *ss, struct nlmsghdr *hdr, int hdrlen __unused,
392 const struct snl_field_parser *ps, int pslen, void *target)
394 for (int i = 0; i < pslen; i++) {
395 const struct snl_field_parser *fp = &ps[i];
396 void *src = (char *)hdr + fp->off_in;
397 void *dst = (char *)target + fp->off_out;
399 fp->cb(ss, src, dst);
404 snl_parse_header(struct snl_state *ss, void *hdr, int len,
405 const struct snl_hdr_parser *parser, void *target)
407 /* Extract fields first (if any) */
408 snl_parse_fields(ss, hdr, parser->hdr_off, parser->fp, parser->fp_size, target);
410 struct nlattr *nla_head = (struct nlattr *)(void *)((char *)hdr + parser->hdr_off);
411 bool result = snl_parse_attrs_raw(ss, nla_head, len - parser->hdr_off,
412 parser->np, parser->np_size, target);
418 snl_parse_nlmsg(struct snl_state *ss, struct nlmsghdr *hdr,
419 const struct snl_hdr_parser *parser, void *target)
421 return (snl_parse_header(ss, hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, target));
425 snl_attr_get_flag(struct snl_state *ss __unused, struct nlattr *nla, void *target)
427 if (NLA_DATA_LEN(nla) == 0) {
428 *((uint8_t *)target) = 1;
435 snl_attr_get_uint8(struct snl_state *ss __unused, struct nlattr *nla,
436 const void *arg __unused, void *target)
438 if (NLA_DATA_LEN(nla) == sizeof(uint8_t)) {
439 *((uint8_t *)target) = *((const uint8_t *)NLA_DATA_CONST(nla));
446 snl_attr_get_uint16(struct snl_state *ss __unused, struct nlattr *nla,
447 const void *arg __unused, void *target)
449 if (NLA_DATA_LEN(nla) == sizeof(uint16_t)) {
450 *((uint16_t *)target) = *((const uint16_t *)NLA_DATA_CONST(nla));
457 snl_attr_get_uint32(struct snl_state *ss __unused, struct nlattr *nla,
458 const void *arg __unused, void *target)
460 if (NLA_DATA_LEN(nla) == sizeof(uint32_t)) {
461 *((uint32_t *)target) = *((const uint32_t *)NLA_DATA_CONST(nla));
468 snl_attr_get_uint64(struct snl_state *ss __unused, struct nlattr *nla,
469 const void *arg __unused, void *target)
471 if (NLA_DATA_LEN(nla) == sizeof(uint64_t)) {
472 memcpy(target, NLA_DATA_CONST(nla), sizeof(uint64_t));
479 snl_attr_get_int8(struct snl_state *ss, struct nlattr *nla, const void *arg,
482 return (snl_attr_get_uint8(ss, nla, arg, target));
486 snl_attr_get_int16(struct snl_state *ss, struct nlattr *nla, const void *arg,
489 return (snl_attr_get_uint16(ss, nla, arg, target));
493 snl_attr_get_int32(struct snl_state *ss, struct nlattr *nla, const void *arg,
496 return (snl_attr_get_uint32(ss, nla, arg, target));
500 snl_attr_get_int64(struct snl_state *ss, struct nlattr *nla, const void *arg,
503 return (snl_attr_get_uint64(ss, nla, arg, target));
507 snl_attr_get_string(struct snl_state *ss __unused, struct nlattr *nla,
508 const void *arg __unused, void *target)
510 size_t maxlen = NLA_DATA_LEN(nla);
512 if (strnlen((char *)NLA_DATA(nla), maxlen) < maxlen) {
513 *((char **)target) = (char *)NLA_DATA(nla);
520 snl_attr_get_stringn(struct snl_state *ss, struct nlattr *nla,
521 const void *arg __unused, void *target)
523 int maxlen = NLA_DATA_LEN(nla);
525 char *buf = snl_allocz(ss, maxlen + 1);
529 memcpy(buf, NLA_DATA(nla), maxlen);
531 *((char **)target) = buf;
536 snl_attr_get_nested(struct snl_state *ss, struct nlattr *nla, const void *arg, void *target)
538 const struct snl_hdr_parser *p = (const struct snl_hdr_parser *)arg;
540 /* Assumes target points to the beginning of the structure */
541 return (snl_parse_header(ss, NLA_DATA(nla), NLA_DATA_LEN(nla), p, target));
545 snl_attr_get_nla(struct snl_state *ss __unused, struct nlattr *nla,
546 const void *arg __unused, void *target)
548 *((struct nlattr **)target) = nla;
553 snl_attr_copy_struct(struct snl_state *ss, struct nlattr *nla,
554 const void *arg __unused, void *target)
556 void *ptr = snl_allocz(ss, NLA_DATA_LEN(nla));
559 memcpy(ptr, NLA_DATA(nla), NLA_DATA_LEN(nla));
560 *((void **)target) = ptr;
567 snl_field_get_uint8(struct snl_state *ss __unused, void *src, void *target)
569 *((uint8_t *)target) = *((uint8_t *)src);
573 snl_field_get_uint16(struct snl_state *ss __unused, void *src, void *target)
575 *((uint16_t *)target) = *((uint16_t *)src);
579 snl_field_get_uint32(struct snl_state *ss __unused, void *src, void *target)
581 *((uint32_t *)target) = *((uint32_t *)src);
585 snl_field_get_ptr(struct snl_state *ss __unused, void *src, void *target)
587 *((void **)target) = src;
590 struct snl_errmsg_data {
591 struct nlmsghdr *orig_hdr;
595 struct nlattr *cookie;
598 #define _IN(_field) offsetof(struct nlmsgerr, _field)
599 #define _OUT(_field) offsetof(struct snl_errmsg_data, _field)
600 static const struct snl_attr_parser nla_p_errmsg[] = {
601 { .type = NLMSGERR_ATTR_MSG, .off = _OUT(error_str), .cb = snl_attr_get_string },
602 { .type = NLMSGERR_ATTR_OFFS, .off = _OUT(error_offs), .cb = snl_attr_get_uint32 },
603 { .type = NLMSGERR_ATTR_COOKIE, .off = _OUT(cookie), .cb = snl_attr_get_nla },
606 static const struct snl_field_parser nlf_p_errmsg[] = {
607 { .off_in = _IN(error), .off_out = _OUT(error), .cb = snl_field_get_uint32 },
608 { .off_in = _IN(msg), .off_out = _OUT(orig_hdr), .cb = snl_field_get_ptr },
612 SNL_DECLARE_PARSER(snl_errmsg_parser, struct nlmsgerr, nlf_p_errmsg, nla_p_errmsg);
614 #define _IN(_field) offsetof(struct nlmsgerr, _field)
615 #define _OUT(_field) offsetof(struct snl_errmsg_data, _field)
616 static const struct snl_attr_parser nla_p_donemsg[] = {};
618 static const struct snl_field_parser nlf_p_donemsg[] = {
619 { .off_in = _IN(error), .off_out = _OUT(error), .cb = snl_field_get_uint32 },
623 SNL_DECLARE_PARSER(snl_donemsg_parser, struct nlmsgerr, nlf_p_donemsg, nla_p_donemsg);
626 snl_parse_errmsg(struct snl_state *ss, struct nlmsghdr *hdr, struct snl_errmsg_data *e)
628 if ((hdr->nlmsg_flags & NLM_F_CAPPED) != 0)
629 return (snl_parse_nlmsg(ss, hdr, &snl_errmsg_parser, e));
631 const struct snl_hdr_parser *ps = &snl_errmsg_parser;
632 struct nlmsgerr *errmsg = (struct nlmsgerr *)(hdr + 1);
633 int hdrlen = sizeof(int) + NLMSG_ALIGN(errmsg->msg.nlmsg_len);
634 struct nlattr *attr_head = (struct nlattr *)(void *)((char *)errmsg + hdrlen);
635 int attr_len = hdr->nlmsg_len - sizeof(struct nlmsghdr) - hdrlen;
637 snl_parse_fields(ss, (struct nlmsghdr *)errmsg, hdrlen, ps->fp, ps->fp_size, e);
638 return (snl_parse_attrs_raw(ss, attr_head, attr_len, ps->np, ps->np_size, e));
642 snl_read_reply_code(struct snl_state *ss, uint32_t nlmsg_seq, struct snl_errmsg_data *e)
644 struct nlmsghdr *hdr = snl_read_reply(ss, nlmsg_seq);
648 } else if (hdr->nlmsg_type == NLMSG_ERROR) {
649 if (!snl_parse_errmsg(ss, hdr, e))
651 return (e->error == 0);
658 * Assumes e is zeroed
660 static inline struct nlmsghdr *
661 snl_read_reply_multi(struct snl_state *ss, uint32_t nlmsg_seq, struct snl_errmsg_data *e)
663 struct nlmsghdr *hdr = snl_read_reply(ss, nlmsg_seq);
667 } else if (hdr->nlmsg_type == NLMSG_ERROR) {
668 if (!snl_parse_errmsg(ss, hdr, e))
670 } if (hdr->nlmsg_type == NLMSG_DONE) {
671 snl_parse_nlmsg(ss, hdr, &snl_donemsg_parser, e);
684 struct nlmsghdr *hdr;
685 struct snl_state *ss;
690 snl_init_writer(struct snl_state *ss, struct snl_writer *nw)
692 nw->size = SNL_WRITER_BUFFER_SIZE;
693 nw->base = snl_allocz(ss, nw->size);
694 if (nw->base == NULL) {
706 snl_realloc_msg_buffer(struct snl_writer *nw, size_t sz)
708 uint32_t new_size = nw->size * 2;
710 while (new_size < nw->size + sz)
716 void *new_base = snl_allocz(nw->ss, new_size);
717 if (new_base == NULL) {
722 memcpy(new_base, nw->base, nw->offset);
723 if (nw->hdr != NULL) {
724 int hdr_off = (char *)(nw->hdr) - nw->base;
725 nw->hdr = (struct nlmsghdr *)(void *)((char *)new_base + hdr_off);
733 snl_reserve_msg_data_raw(struct snl_writer *nw, size_t sz)
735 sz = NETLINK_ALIGN(sz);
737 if (__predict_false(nw->offset + sz > nw->size)) {
738 if (!snl_realloc_msg_buffer(nw, sz))
742 void *data_ptr = &nw->base[nw->offset];
747 #define snl_reserve_msg_object(_ns, _t) ((_t *)snl_reserve_msg_data_raw(_ns, sizeof(_t)))
748 #define snl_reserve_msg_data(_ns, _sz, _t) ((_t *)snl_reserve_msg_data_raw(_ns, _sz))
751 _snl_reserve_msg_attr(struct snl_writer *nw, uint16_t nla_type, uint16_t sz)
753 sz += sizeof(struct nlattr);
755 struct nlattr *nla = snl_reserve_msg_data(nw, sz, struct nlattr);
756 if (__predict_false(nla == NULL))
758 nla->nla_type = nla_type;
761 return ((void *)(nla + 1));
763 #define snl_reserve_msg_attr(_ns, _at, _t) ((_t *)_snl_reserve_msg_attr(_ns, _at, sizeof(_t)))
766 snl_add_msg_attr(struct snl_writer *nw, int attr_type, int attr_len, const void *data)
768 int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr));
770 if (__predict_false(nw->offset + required_len > nw->size)) {
771 if (!snl_realloc_msg_buffer(nw, required_len))
775 struct nlattr *nla = (struct nlattr *)(void *)(&nw->base[nw->offset]);
777 nla->nla_len = attr_len + sizeof(struct nlattr);
778 nla->nla_type = attr_type;
780 if ((attr_len % 4) != 0) {
781 /* clear padding bytes */
782 bzero((char *)nla + required_len - 4, 4);
784 memcpy((nla + 1), data, attr_len);
786 nw->offset += required_len;
791 snl_add_msg_attr_raw(struct snl_writer *nw, const struct nlattr *nla_src)
793 int attr_len = nla_src->nla_len - sizeof(struct nlattr);
795 assert(attr_len >= 0);
797 return (snl_add_msg_attr(nw, nla_src->nla_type, attr_len, (const void *)(nla_src + 1)));
801 snl_add_msg_attr_u8(struct snl_writer *nw, int attrtype, uint8_t value)
803 return (snl_add_msg_attr(nw, attrtype, sizeof(uint8_t), &value));
807 snl_add_msg_attr_u16(struct snl_writer *nw, int attrtype, uint16_t value)
809 return (snl_add_msg_attr(nw, attrtype, sizeof(uint16_t), &value));
813 snl_add_msg_attr_u32(struct snl_writer *nw, int attrtype, uint32_t value)
815 return (snl_add_msg_attr(nw, attrtype, sizeof(uint32_t), &value));
819 snl_add_msg_attr_u64(struct snl_writer *nw, int attrtype, uint64_t value)
821 return (snl_add_msg_attr(nw, attrtype, sizeof(uint64_t), &value));
825 snl_add_msg_attr_s8(struct snl_writer *nw, int attrtype, int8_t value)
827 return (snl_add_msg_attr(nw, attrtype, sizeof(int8_t), &value));
831 snl_add_msg_attr_s16(struct snl_writer *nw, int attrtype, int16_t value)
833 return (snl_add_msg_attr(nw, attrtype, sizeof(int16_t), &value));
837 snl_add_msg_attr_s32(struct snl_writer *nw, int attrtype, int32_t value)
839 return (snl_add_msg_attr(nw, attrtype, sizeof(int32_t), &value));
843 snl_add_msg_attr_s64(struct snl_writer *nw, int attrtype, int64_t value)
845 return (snl_add_msg_attr(nw, attrtype, sizeof(int64_t), &value));
849 snl_add_msg_attr_flag(struct snl_writer *nw, int attrtype)
851 return (snl_add_msg_attr(nw, attrtype, 0, NULL));
855 snl_add_msg_attr_string(struct snl_writer *nw, int attrtype, const char *str)
857 return (snl_add_msg_attr(nw, attrtype, strlen(str) + 1, str));
862 snl_get_msg_offset(const struct snl_writer *nw)
864 return (nw->offset - ((char *)nw->hdr - nw->base));
868 _snl_restore_msg_offset(const struct snl_writer *nw, int off)
870 return ((void *)((char *)nw->hdr + off));
872 #define snl_restore_msg_offset(_ns, _off, _t) ((_t *)_snl_restore_msg_offset(_ns, _off))
875 snl_add_msg_attr_nested(struct snl_writer *nw, int attrtype)
877 int off = snl_get_msg_offset(nw);
878 struct nlattr *nla = snl_reserve_msg_data(nw, sizeof(struct nlattr), struct nlattr);
879 if (__predict_false(nla == NULL))
881 nla->nla_type = attrtype;
886 snl_end_attr_nested(const struct snl_writer *nw, int off)
889 struct nlattr *nla = snl_restore_msg_offset(nw, off, struct nlattr);
890 nla->nla_len = NETLINK_ALIGN(snl_get_msg_offset(nw) - off);
894 static inline struct nlmsghdr *
895 snl_create_msg_request(struct snl_writer *nw, int nlmsg_type)
897 assert(nw->hdr == NULL);
899 struct nlmsghdr *hdr = snl_reserve_msg_object(nw, struct nlmsghdr);
900 hdr->nlmsg_type = nlmsg_type;
901 hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
908 snl_abort_msg(struct snl_writer *nw)
910 if (nw->hdr != NULL) {
911 int offset = (char *)(&nw->base[nw->offset]) - (char *)(nw->hdr);
913 nw->offset -= offset;
918 static inline struct nlmsghdr *
919 snl_finalize_msg(struct snl_writer *nw)
923 if (nw->hdr != NULL) {
924 struct nlmsghdr *hdr = nw->hdr;
926 int offset = (char *)(&nw->base[nw->offset]) - (char *)(nw->hdr);
927 hdr->nlmsg_len = offset;
928 hdr->nlmsg_seq = snl_get_seq(nw->ss);
937 snl_send_msgs(struct snl_writer *nw)
939 int offset = nw->offset;
941 assert(nw->hdr == NULL);
944 return (snl_send(nw->ss, nw->base, offset));
947 static const struct snl_hdr_parser *snl_all_core_parsers[] = {
948 &snl_errmsg_parser, &snl_donemsg_parser,