Management

Collaboration diagram for Management:

Modules
	Controller

Data Structures
struct	genl_cmd
	Generic Netlink Command. More...
struct	genl_ops
	Generic Netlink Operations. More...

Functions
char *	genl_op2name (int family, int op, char *buf, size_t len)

Register/Unregister
int	genl_register (struct nl_cache_ops *ops)
	Register generic netlink operations. More...
void	genl_unregister (struct nl_cache_ops *ops)
	Unregister generic netlink operations. More...

Resolving ID/Name
int	genl_ops_resolve (struct nl_sock *sk, struct genl_ops *ops)
int	genl_mngt_resolve (struct nl_sock *sk)

Detailed Description

1) Registering a generic netlink module

#include <netlink/genl/mngt.h>

// First step is to define all the commands being used in
// particular generic netlink family. The ID and name are
// mandatory to be filled out. A callback function and
// most the attribute policy that comes with it must be
// defined for commands expected to be issued towards
// userspace.
static struct genl_cmd foo_cmds[] = {
    {
        .c_id       = FOO_CMD_NEW,
        .c_name     = "NEWFOO" ,
        .c_maxattr  = FOO_ATTR_MAX,
        .c_attr_policy  = foo_policy,
        .c_msg_parser   = foo_msg_parser,
    },
    {
        .c_id       = FOO_CMD_DEL,
        .c_name     = "DELFOO" ,
    },
};

// The list of commands must then be integrated into a
// struct genl_ops serving as handle for this particular
// family.
static struct genl_ops my_genl_ops = {
    .o_cmds         = foo_cmds,
    .o_ncmds        = ARRAY_SIZE(foo_cmds),
};

// Using the above struct genl_ops an arbitary number of
// cache handles can be associated to it.
//
// The macro GENL_HDRSIZE() must be used to specify the
// length of the header to automatically take headers on
// generic layers into account.
//
// The macro GENL_FAMILY() is used to represent the generic
// netlink family id.
static struct nl_cache_ops genl_foo_ops = {
    .co_name        = "genl/foo",
    .co_hdrsize     = GENL_HDRSIZE(sizeof(struct my_hdr)),
    .co_msgtypes        = GENL_FAMILY(GENL_ID_GENERATE, "foo"),
    .co_genl        = &my_genl_ops,
    .co_protocol        = NETLINK_GENERIC,
    .co_request_update      = foo_request_update,
    .co_obj_ops     = &genl_foo_ops,
};

// Finally each cache handle for a generic netlink family
// must be registered using genl_register().
static void __init foo_init(void)
{
    genl_register(&genl_foo_ops);
}

// ... respectively unregsted again.
static void __exit foo_exit(void)
{
    genl_unregister(&genl_foo_ops);
}

Function Documentation

int genl_mngt_resolve

(

struct nl_sock *

sk

)

References genl_ctrl_alloc_cache(), nl_cache_free(), nl_list_for_each_entry, and genl_ops::o_list.

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char* genl_op2name	(	int	family,
		int	op,
		char *	buf,
		size_t	len
	)

References buf, genl_cmd::c_id, genl_cmd::c_name, nl_list_for_each_entry, NULL, genl_ops::o_cmds, genl_ops::o_family, genl_ops::o_list, and genl_ops::o_ncmds.

int genl_ops_resolve	(	struct nl_sock *	sk,
		struct genl_ops *	ops
	)

References genl_ctrl_alloc_cache(), and nl_cache_free().

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int genl_register

(

struct nl_cache_ops *

ops

)

Register generic netlink operations.

• ops cache operations

References nl_cache_ops::co_genl, nl_cache_ops::co_hdrsize, nl_cache_ops::co_msg_parser, nl_cache_ops::co_msgtypes, nl_cache_ops::co_protocol, GENL_HDRSIZE, nl_msgtype::mt_id, nl_msgtype::mt_name, NETLINK_GENERIC, nl_cache_mngt_register(), NLE_INVAL, NLE_PROTO_MISMATCH, NULL, genl_ops::o_cache_ops, genl_ops::o_family, genl_ops::o_list, and genl_ops::o_name.

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void genl_unregister

(

struct nl_cache_ops *

ops

)

Unregister generic netlink operations.

• ops cache operations

References nl_cache_ops::co_genl, nl_cache_mngt_unregister(), and genl_ops::o_list.

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