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