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309 lines
7.2 KiB
C
309 lines
7.2 KiB
C
/*
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* netlink/msg.c Netlink Messages Interface
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation version 2.1
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* of the License.
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*
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* Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
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*/
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#ifndef NETLINK_MSG_H_
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#define NETLINK_MSG_H_
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#include <netlink/netlink.h>
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#include <netlink/object.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct nla_policy;
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#define NL_DONTPAD 0
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/**
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* @ingroup msg
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* @brief
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* Will cause the netlink pid to be set to the pid assigned to
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* the netlink handle (socket) just before sending the message off.
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* @note Requires the use of nl_send_auto_complete()!
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*/
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#define NL_AUTO_PID 0
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/**
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* @ingroup msg
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* @brief
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* May be used to refer to a sequence number which should be
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* automatically set just before sending the message off.
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* @note Requires the use of nl_send_auto_complete()!
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*/
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#define NL_AUTO_SEQ 0
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#define NL_MSG_CRED_PRESENT 1
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struct nl_msg
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{
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int nm_protocol;
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int nm_flags;
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struct sockaddr_nl nm_src;
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struct sockaddr_nl nm_dst;
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struct ucred nm_creds;
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struct nlmsghdr * nm_nlh;
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size_t nm_size;
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int nm_refcnt;
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};
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struct nl_msg;
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struct nl_tree;
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struct ucred;
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/* message parsing */
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extern int nlmsg_ok(const struct nlmsghdr *, int);
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extern struct nlmsghdr * nlmsg_next(struct nlmsghdr *, int *);
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extern int nlmsg_parse(struct nlmsghdr *, int, struct nlattr **,
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int, struct nla_policy *);
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extern int nlmsg_validate(struct nlmsghdr *, int, int,
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struct nla_policy *);
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extern struct nl_msg * nlmsg_alloc(void);
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extern struct nl_msg * nlmsg_alloc_size(size_t);
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extern struct nl_msg * nlmsg_alloc_simple(int, int);
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extern void nlmsg_set_default_size(size_t);
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extern struct nl_msg * nlmsg_inherit(struct nlmsghdr *);
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extern struct nl_msg * nlmsg_convert(struct nlmsghdr *);
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extern void * nlmsg_reserve(struct nl_msg *, size_t, int);
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extern int nlmsg_append(struct nl_msg *, void *, size_t, int);
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extern struct nlmsghdr * nlmsg_put(struct nl_msg *, uint32_t, uint32_t,
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int, int, int);
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extern void nlmsg_free(struct nl_msg *);
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extern int nl_msg_parse(struct nl_msg *,
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void (*cb)(struct nl_object *, void *),
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void *);
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extern void nl_msg_dump(struct nl_msg *, FILE *);
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/**
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* length of netlink message not including padding
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* @arg payload length of message payload
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*/
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static inline int nlmsg_msg_size(int payload)
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{
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return NLMSG_HDRLEN + payload;
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}
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/**
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* length of netlink message including padding
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* @arg payload length of message payload
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*/
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static inline int nlmsg_total_size(int payload)
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{
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return NLMSG_ALIGN(nlmsg_msg_size(payload));
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}
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/**
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* length of padding at the message's tail
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* @arg payload length of message payload
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*/
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static inline int nlmsg_padlen(int payload)
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{
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return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
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}
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/**
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* head of message payload
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* @arg nlh netlink messsage header
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*/
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static inline void *nlmsg_data(const struct nlmsghdr *nlh)
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{
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return (unsigned char *) nlh + NLMSG_HDRLEN;
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}
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static inline void *nlmsg_tail(const struct nlmsghdr *nlh)
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{
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return (unsigned char *) nlh + NLMSG_ALIGN(nlh->nlmsg_len);
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}
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/**
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* length of message payload
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* @arg nlh netlink message header
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*/
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static inline int nlmsg_len(const struct nlmsghdr *nlh)
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{
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return nlh->nlmsg_len - NLMSG_HDRLEN;
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}
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/**
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* head of attributes data
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* @arg nlh netlink message header
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* @arg hdrlen length of family specific header
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*/
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static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh, int hdrlen)
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{
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unsigned char *data = (unsigned char*)nlmsg_data(nlh);
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return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
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}
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/**
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* length of attributes data
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* @arg nlh netlink message header
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* @arg hdrlen length of family specific header
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*/
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static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
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{
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return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
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}
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static inline int nlmsg_valid_hdr(const struct nlmsghdr *nlh, int hdrlen)
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{
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if (nlh->nlmsg_len < (uint)nlmsg_msg_size(hdrlen))
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return 0;
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return 1;
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}
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static inline void nlmsg_set_proto(struct nl_msg *msg, int protocol)
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{
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msg->nm_protocol = protocol;
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}
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static inline int nlmsg_get_proto(struct nl_msg *msg)
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{
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return msg->nm_protocol;
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}
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static inline size_t nlmsg_get_max_size(struct nl_msg *msg)
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{
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return msg->nm_size;
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}
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static inline void nlmsg_set_src(struct nl_msg *msg, struct sockaddr_nl *addr)
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{
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memcpy(&msg->nm_src, addr, sizeof(*addr));
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}
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static inline struct sockaddr_nl *nlmsg_get_src(struct nl_msg *msg)
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{
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return &msg->nm_src;
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}
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static inline void nlmsg_set_dst(struct nl_msg *msg, struct sockaddr_nl *addr)
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{
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memcpy(&msg->nm_dst, addr, sizeof(*addr));
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}
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static inline struct sockaddr_nl *nlmsg_get_dst(struct nl_msg *msg)
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{
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return &msg->nm_dst;
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}
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static inline void nlmsg_set_creds(struct nl_msg *msg, struct ucred *creds)
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{
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memcpy(&msg->nm_creds, creds, sizeof(*creds));
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msg->nm_flags |= NL_MSG_CRED_PRESENT;
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}
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static inline struct ucred *nlmsg_get_creds(struct nl_msg *msg)
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{
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if (msg->nm_flags & NL_MSG_CRED_PRESENT)
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return &msg->nm_creds;
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return NULL;
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}
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/**
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* Return actual netlink message
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* @arg n netlink message
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*
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* Returns the actual netlink message casted to the type of the netlink
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* message header.
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*
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* @return A pointer to the netlink message.
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*/
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static inline struct nlmsghdr *nlmsg_hdr(struct nl_msg *n)
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{
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return n->nm_nlh;
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}
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/**
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* Acquire a reference on a netlink message
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* @arg msg message to acquire reference from
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*/
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static inline void nlmsg_get(struct nl_msg *msg)
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{
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msg->nm_refcnt++;
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}
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/**
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* Expand maximum payload size of a netlink message
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* @arg n Netlink message.
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* @arg newlen New maximum payload size.
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*
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* Reallocates the payload section of a netlink message and increases
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* the maximum payload size of the message.
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*
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* @note Any pointers pointing to old payload block will be stale and
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* need to be refetched. Therfore, do not expand while constructing
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* nested attributes or while reserved data blocks are held.
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*
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* @return 0 on success or a negative error code.
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*/
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static inline int nlmsg_expand(struct nl_msg *n, size_t newlen)
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{
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void *tmp;
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if (newlen <= n->nm_size)
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return -NLE_INVAL;
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tmp = realloc(n->nm_nlh, newlen);
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if (tmp == NULL)
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return -NLE_NOMEM;
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n->nm_nlh = (struct nlmsghdr*)tmp;
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n->nm_size = newlen;
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return 0;
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}
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/**
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* @name Iterators
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* @{
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*/
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/**
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* @ingroup msg
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* Iterate over a stream of attributes in a message
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* @arg pos loop counter, set to current attribute
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* @arg nlh netlink message header
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* @arg hdrlen length of family header
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* @arg rem initialized to len, holds bytes currently remaining in stream
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*/
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#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
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nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
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nlmsg_attrlen(nlh, hdrlen), rem)
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/**
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* Iterate over a stream of messages
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* @arg pos loop counter, set to current message
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* @arg head head of message stream
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* @arg len length of message stream
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* @arg rem initialized to len, holds bytes currently remaining in stream
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*/
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#define nlmsg_for_each_msg(pos, head, len, rem) \
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for (pos = head, rem = len; \
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nlmsg_ok(pos, rem); \
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pos = nlmsg_next(pos, &(rem)))
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/** @} */
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#ifdef __cplusplus
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}
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#endif
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#endif
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