You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
394 lines
9.9 KiB
394 lines
9.9 KiB
/* SPDX-License-Identifier: LGPL-2.1-only */
|
|
/*
|
|
* lib/genl/genl.c Generic Netlink
|
|
*
|
|
* 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) 2003-2012 Thomas Graf <tgraf@suug.ch>
|
|
*/
|
|
|
|
/**
|
|
* @defgroup genl Generic Netlink Library (libnl-genl)
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
#include <netlink-private/genl.h>
|
|
#include <netlink/netlink.h>
|
|
#include <netlink/genl/genl.h>
|
|
#include <netlink/utils.h>
|
|
|
|
/**
|
|
* @name Generic Netlink Socket
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Connect a Generic Netlink socket
|
|
* @arg sk Unconnected Netlink socket
|
|
*
|
|
* This function expects a struct nl_socket object previously allocated via
|
|
* nl_socket_alloc(). It calls nl_connect() to create the local socket file
|
|
* descriptor and binds the socket to the \c NETLINK_GENERIC Netlink protocol.
|
|
*
|
|
* Using this function is equivalent to:
|
|
* @code
|
|
* nl_connect(sk, NETLINK_GENERIC);
|
|
* @endcode
|
|
*
|
|
* @see nl_connect()
|
|
*
|
|
* @return 0 on success or a negative error code.
|
|
*/
|
|
int genl_connect(struct nl_sock *sk)
|
|
{
|
|
return nl_connect(sk, NETLINK_GENERIC);
|
|
}
|
|
|
|
/** @} */
|
|
|
|
/**
|
|
* @name Sending Data
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Send a Generic Netlink message consisting only of a header
|
|
* @arg sk Generic Netlink socket
|
|
* @arg family Numeric family identifier
|
|
* @arg cmd Numeric command identifier
|
|
* @arg version Interface version
|
|
* @arg flags Additional Netlink message flags (optional)
|
|
*
|
|
* This function is a shortcut for sending a Generic Netlink message without
|
|
* any message payload. The message will only consist of the Netlink and
|
|
* Generic Netlink headers. The header is constructed based on the specified
|
|
* parameters and passed on to nl_send_simple() to send it on the specified
|
|
* socket.
|
|
*
|
|
* @par Example:
|
|
* @code
|
|
* #include <netlink/genl/genl.h>
|
|
* #include <linux/genetlink.h>
|
|
*
|
|
* err = genl_send_simple(sk, GENL_ID_CTRL, CTRL_CMD_GETFAMILY, CTRL_VERSION,
|
|
* NLM_F_DUMP);
|
|
* @endcode
|
|
*
|
|
* @see nl_send_simple()
|
|
*
|
|
* @return 0 on success or a negative error code. Due to a bug, this function
|
|
* returns the number of bytes sent. Treat any non-negative number as success.
|
|
*/
|
|
int genl_send_simple(struct nl_sock *sk, int family, int cmd,
|
|
int version, int flags)
|
|
{
|
|
struct genlmsghdr hdr = {
|
|
.cmd = cmd,
|
|
.version = version,
|
|
};
|
|
|
|
return nl_send_simple(sk, family, flags, &hdr, sizeof(hdr));
|
|
}
|
|
|
|
/** @} */
|
|
|
|
/**
|
|
* @name Message Parsing
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Validate Generic Netlink message headers
|
|
* @arg nlh Pointer to Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
*
|
|
* Verifies the integrity of the Netlink and Generic Netlink headers by
|
|
* enforcing the following requirements:
|
|
* - Valid Netlink message header (nlmsg_valid_hdr())
|
|
* - Presence of a complete Generic Netlink header
|
|
* - At least \c hdrlen bytes of payload included after the generic
|
|
* netlink header.
|
|
*
|
|
* @return A positive integer (true) if the headers are valid or
|
|
* 0 (false) if not.
|
|
*/
|
|
int genlmsg_valid_hdr(struct nlmsghdr *nlh, int hdrlen)
|
|
{
|
|
struct genlmsghdr *ghdr;
|
|
|
|
if (!nlmsg_valid_hdr(nlh, GENL_HDRLEN))
|
|
return 0;
|
|
|
|
ghdr = nlmsg_data(nlh);
|
|
if (genlmsg_len(ghdr) < NLMSG_ALIGN(hdrlen))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* Validate Generic Netlink message including attributes
|
|
* @arg nlh Pointer to Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
* @arg maxtype Maximum attribtue id expected
|
|
* @arg policy Attribute validation policy
|
|
*
|
|
* Verifies the validity of the Netlink and Generic Netlink headers using
|
|
* genlmsg_valid_hdr() and calls nla_validate() on the message payload to
|
|
* verify the integrity of eventual attributes.
|
|
*
|
|
* @note You may call genlmsg_parse() directly to perform validation and
|
|
* parsing in a single step.
|
|
*
|
|
* @see genlmsg_valid_hdr()
|
|
* @see nla_validate()
|
|
* @see genlmsg_parse()
|
|
*
|
|
* @return 0 on success or a negative error code.
|
|
*/
|
|
int genlmsg_validate(struct nlmsghdr *nlh, int hdrlen, int maxtype,
|
|
const struct nla_policy *policy)
|
|
{
|
|
struct genlmsghdr *ghdr;
|
|
|
|
if (!genlmsg_valid_hdr(nlh, hdrlen))
|
|
return -NLE_MSG_TOOSHORT;
|
|
|
|
ghdr = nlmsg_data(nlh);
|
|
return nla_validate(genlmsg_attrdata(ghdr, hdrlen),
|
|
genlmsg_attrlen(ghdr, hdrlen), maxtype, policy);
|
|
}
|
|
|
|
/**
|
|
* Parse Generic Netlink message including attributes
|
|
* @arg nlh Pointer to Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
* @arg tb Array to store parsed attributes
|
|
* @arg maxtype Maximum attribute id expected
|
|
* @arg policy Attribute validation policy
|
|
*
|
|
* Verifies the validity of the Netlink and Generic Netlink headers using
|
|
* genlmsg_valid_hdr() and calls nla_parse() on the message payload to
|
|
* parse eventual attributes.
|
|
*
|
|
* @par Example:
|
|
* @code
|
|
* struct nlattr *attrs[MY_TYPE_MAX+1];
|
|
*
|
|
* if ((err = genlmsg_parse(nlmsg_hdr(msg), sizeof(struct my_hdr), attrs,
|
|
* MY_TYPE_MAX, attr_policy)) < 0)
|
|
* // ERROR
|
|
* @endcode
|
|
*
|
|
* @see genlmsg_valid_hdr()
|
|
* @see genlmsg_validate()
|
|
* @see nla_parse()
|
|
*
|
|
* @return 0 on success or a negative error code.
|
|
*/
|
|
int genlmsg_parse(struct nlmsghdr *nlh, int hdrlen, struct nlattr *tb[],
|
|
int maxtype, const struct nla_policy *policy)
|
|
{
|
|
struct genlmsghdr *ghdr;
|
|
|
|
if (!genlmsg_valid_hdr(nlh, hdrlen))
|
|
return -NLE_MSG_TOOSHORT;
|
|
|
|
ghdr = nlmsg_data(nlh);
|
|
return nla_parse(tb, maxtype, genlmsg_attrdata(ghdr, hdrlen),
|
|
genlmsg_attrlen(ghdr, hdrlen), policy);
|
|
}
|
|
|
|
/**
|
|
* Return pointer to Generic Netlink header
|
|
* @arg nlh Netlink message header
|
|
*
|
|
* @return Pointer to Generic Netlink message header
|
|
*/
|
|
struct genlmsghdr *genlmsg_hdr(struct nlmsghdr *nlh)
|
|
{
|
|
return nlmsg_data(nlh);
|
|
}
|
|
|
|
/**
|
|
* Return length of message payload including user header
|
|
* @arg gnlh Generic Netlink message header
|
|
*
|
|
* @see genlmsg_data()
|
|
*
|
|
* @return Length of user payload including an eventual user header in
|
|
* number of bytes.
|
|
*/
|
|
int genlmsg_len(const struct genlmsghdr *gnlh)
|
|
{
|
|
const struct nlmsghdr *nlh;
|
|
|
|
nlh = (const struct nlmsghdr *)((const unsigned char *) gnlh - NLMSG_HDRLEN);
|
|
return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
|
|
}
|
|
|
|
|
|
/**
|
|
* Return pointer to user header
|
|
* @arg gnlh Generic Netlink message header
|
|
*
|
|
* Calculates the pointer to the user header based on the pointer to
|
|
* the Generic Netlink message header.
|
|
*
|
|
* @return Pointer to the user header
|
|
*/
|
|
void *genlmsg_user_hdr(const struct genlmsghdr *gnlh)
|
|
{
|
|
return genlmsg_data(gnlh);
|
|
}
|
|
|
|
/**
|
|
* Return pointer to user data
|
|
* @arg gnlh Generic netlink message header
|
|
* @arg hdrlen Length of user header
|
|
*
|
|
* Calculates the pointer to the user data based on the pointer to
|
|
* the Generic Netlink message header.
|
|
*
|
|
* @see genlmsg_user_datalen()
|
|
*
|
|
* @return Pointer to the user data
|
|
*/
|
|
void *genlmsg_user_data(const struct genlmsghdr *gnlh, const int hdrlen)
|
|
{
|
|
return (char *) genlmsg_user_hdr(gnlh) + NLMSG_ALIGN(hdrlen);
|
|
}
|
|
|
|
/**
|
|
* Return length of user data
|
|
* @arg gnlh Generic Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
*
|
|
* @see genlmsg_user_data()
|
|
*
|
|
* @return Length of user data in bytes
|
|
*/
|
|
int genlmsg_user_datalen(const struct genlmsghdr *gnlh, const int hdrlen)
|
|
{
|
|
return genlmsg_len(gnlh) - NLMSG_ALIGN(hdrlen);
|
|
}
|
|
|
|
/**
|
|
* Return pointer to message attributes
|
|
* @arg gnlh Generic Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
*
|
|
* @see genlmsg_attrlen()
|
|
*
|
|
* @return Pointer to the start of the message's attributes section.
|
|
*/
|
|
struct nlattr *genlmsg_attrdata(const struct genlmsghdr *gnlh, int hdrlen)
|
|
{
|
|
return genlmsg_user_data(gnlh, hdrlen);
|
|
}
|
|
|
|
/**
|
|
* Return length of message attributes
|
|
* @arg gnlh Generic Netlink message header
|
|
* @arg hdrlen Length of user header
|
|
*
|
|
* @see genlmsg_attrdata()
|
|
*
|
|
* @return Length of the message section containing attributes in number
|
|
* of bytes.
|
|
*/
|
|
int genlmsg_attrlen(const struct genlmsghdr *gnlh, int hdrlen)
|
|
{
|
|
return genlmsg_len(gnlh) - NLMSG_ALIGN(hdrlen);
|
|
}
|
|
|
|
/** @} */
|
|
|
|
/**
|
|
* @name Message Construction
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Add Generic Netlink headers to Netlink message
|
|
* @arg msg Netlink message object
|
|
* @arg port Netlink port or NL_AUTO_PORT
|
|
* @arg seq Sequence number of message or NL_AUTO_SEQ
|
|
* @arg family Numeric family identifier
|
|
* @arg hdrlen Length of user header
|
|
* @arg flags Additional Netlink message flags (optional)
|
|
* @arg cmd Numeric command identifier
|
|
* @arg version Interface version
|
|
*
|
|
* Calls nlmsg_put() on the specified message object to reserve space for
|
|
* the Netlink header, the Generic Netlink header, and a user header of
|
|
* specified length. Fills out the header fields with the specified
|
|
* parameters.
|
|
*
|
|
* @par Example:
|
|
* @code
|
|
* struct nl_msg *msg;
|
|
* struct my_hdr *user_hdr;
|
|
*
|
|
* if (!(msg = nlmsg_alloc()))
|
|
* // ERROR
|
|
*
|
|
* user_hdr = genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, family_id,
|
|
* sizeof(struct my_hdr), 0, MY_CMD_FOO, 0);
|
|
* if (!user_hdr)
|
|
* // ERROR
|
|
* @endcode
|
|
*
|
|
* @see nlmsg_put()
|
|
*
|
|
* Returns Pointer to user header or NULL if an error occurred.
|
|
*/
|
|
void *genlmsg_put(struct nl_msg *msg, uint32_t port, uint32_t seq, int family,
|
|
int hdrlen, int flags, uint8_t cmd, uint8_t version)
|
|
{
|
|
struct nlmsghdr *nlh;
|
|
struct genlmsghdr hdr = {
|
|
.cmd = cmd,
|
|
.version = version,
|
|
};
|
|
|
|
nlh = nlmsg_put(msg, port, seq, family, GENL_HDRLEN + hdrlen, flags);
|
|
if (nlh == NULL)
|
|
return NULL;
|
|
|
|
memcpy(nlmsg_data(nlh), &hdr, sizeof(hdr));
|
|
NL_DBG(2, "msg %p: Added generic netlink header cmd=%d version=%d\n",
|
|
msg, cmd, version);
|
|
|
|
return (char *) nlmsg_data(nlh) + GENL_HDRLEN;
|
|
}
|
|
|
|
/** @} */
|
|
|
|
/**
|
|
* @name Deprecated
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Return pointer to message payload
|
|
* @arg gnlh Generic Netlink message header
|
|
*
|
|
* @deprecated This function has been deprecated due to inability to specify
|
|
* the length of the user header. Use genlmsg_user_hdr()
|
|
* respectively genlmsg_user_data().
|
|
*
|
|
* @return Pointer to payload section
|
|
*/
|
|
void *genlmsg_data(const struct genlmsghdr *gnlh)
|
|
{
|
|
return ((unsigned char *) gnlh + GENL_HDRLEN);
|
|
}
|
|
|
|
/** @} */
|
|
/** @} */
|