253 lines
7.8 KiB
C
253 lines
7.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2021 Ng Peng Nam Sean
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* Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _NETLINK_NETLINK_MESSAGE_WRITER_H_
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#define _NETLINK_NETLINK_MESSAGE_WRITER_H_
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#ifdef _KERNEL
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/*
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* It is not meant to be included directly
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*/
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struct mbuf;
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struct nl_writer;
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typedef bool nl_writer_cb(struct nl_writer *nw, void *buf, int buflen, int cnt);
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struct nl_writer {
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int alloc_len; /* allocated buffer length */
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int offset; /* offset from the start of the buffer */
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struct nlmsghdr *hdr; /* Pointer to the currently-filled msg */
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char *data; /* pointer to the contiguous storage */
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void *_storage; /* Underlying storage pointer */
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nl_writer_cb *cb; /* Callback to flush data */
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union {
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void *arg_ptr; /* Callback argument as pointer */
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uint64_t arg_uint; /* Callback argument as int */
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};
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int num_messages; /* Number of messages in the buffer */
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int malloc_flag; /* M_WAITOK or M_NOWAIT */
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uint8_t writer_type; /* NS_WRITER_TYPE_* */
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uint8_t writer_target; /* NS_WRITER_TARGET_* */
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bool ignore_limit; /* If true, ignores RCVBUF limit */
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bool enomem; /* True if ENOMEM occured */
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};
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#define NS_WRITER_TARGET_SOCKET 0
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#define NS_WRITER_TARGET_GROUP 1
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#define NS_WRITER_TARGET_CHAIN 2
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#define NS_WRITER_TYPE_MBUF 0
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#define NS_WRITER_TYPE_BUF 1
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#define NS_WRITER_TYPE_LBUF 2
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#define NS_WRITER_TYPE_MBUFC 3
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#define NLMSG_SMALL 128
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#define NLMSG_LARGE 2048
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/* Message and attribute writing */
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struct nlpcb;
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bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp);
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bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
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bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm);
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bool nlmsg_flush(struct nl_writer *nw);
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void nlmsg_ignore_limit(struct nl_writer *nw);
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bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size);
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bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
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uint16_t flags, uint32_t len);
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bool nlmsg_end(struct nl_writer *nw);
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void nlmsg_abort(struct nl_writer *nw);
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bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr);
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static inline bool
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nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len)
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{
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return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type,
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hdr->nlmsg_flags, payload_len));
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}
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#define nlmsg_data(_hdr) ((void *)((_hdr) + 1))
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/*
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* KPI similar to mtodo():
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* current (uncompleted) header is guaranteed to be contiguous,
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* but can be reallocated, thus pointers may need to be readjusted.
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*/
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static inline int
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nlattr_save_offset(const struct nl_writer *nw)
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{
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return (nw->offset - ((char *)nw->hdr - nw->data));
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}
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static inline void *
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_nlattr_restore_offset(const struct nl_writer *nw, int off)
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{
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return ((void *)((char *)nw->hdr + off));
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}
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#define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off))
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static inline void
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nlattr_set_len(const struct nl_writer *nw, int off)
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{
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struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr);
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nla->nla_len = nlattr_save_offset(nw) - off;
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}
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static inline void *
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nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz)
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{
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if (__predict_false(nw->offset + NETLINK_ALIGN(sz) > nw->alloc_len)) {
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if (!nlmsg_refill_buffer(nw, NETLINK_ALIGN(sz)))
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return (NULL);
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}
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void *data_ptr = &nw->data[nw->offset];
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nw->offset += NLMSG_ALIGN(sz);
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return (data_ptr);
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}
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#define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, NLA_ALIGN(sizeof(_t))))
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#define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz))
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static inline int
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nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type)
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{
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int off = nlattr_save_offset(nw);
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struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr);
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if (__predict_false(nla == NULL))
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return (0);
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nla->nla_type = nla_type;
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return (off);
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}
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static inline void *
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_nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz)
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{
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sz += sizeof(struct nlattr);
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struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr);
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if (__predict_false(nla == NULL))
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return (NULL);
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nla->nla_type = nla_type;
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nla->nla_len = sz;
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return ((void *)(nla + 1));
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}
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#define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t))))
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static inline bool
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nlattr_add(struct nl_writer *nw, int attr_type, int attr_len, const void *data)
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{
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int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr));
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if (__predict_false(nw->offset + required_len > nw->alloc_len)) {
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if (!nlmsg_refill_buffer(nw, required_len))
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return (false);
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}
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struct nlattr *nla = (struct nlattr *)(&nw->data[nw->offset]);
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nla->nla_len = attr_len + sizeof(struct nlattr);
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nla->nla_type = attr_type;
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if (attr_len > 0) {
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if ((attr_len % 4) != 0) {
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/* clear padding bytes */
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bzero((char *)nla + required_len - 4, 4);
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}
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memcpy((nla + 1), data, attr_len);
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}
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nw->offset += required_len;
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return (true);
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}
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static inline bool
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nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value));
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}
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static inline bool
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nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value));
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}
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static inline bool
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nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value));
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}
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static inline bool
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nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value));
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}
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static inline bool
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nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(int8_t), &value));
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}
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static inline bool
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nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(int16_t), &value));
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}
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static inline bool
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nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(int32_t), &value));
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}
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static inline bool
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nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value)
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{
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return (nlattr_add(nw, attrtype, sizeof(int64_t), &value));
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}
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static inline bool
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nlattr_add_flag(struct nl_writer *nw, int attrtype)
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{
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return (nlattr_add(nw, attrtype, 0, NULL));
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}
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static inline bool
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nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str)
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{
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return (nlattr_add(nw, attrtype, strlen(str) + 1, str));
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}
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#endif
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#endif
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