libnl  1.1
Modules | Data Structures | Functions
Management
Generic Netlink

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.
void genl_unregister (struct nl_cache_ops *ops)
 Unregister generic netlink operations.

Resolving ID/Name

int genl_ops_resolve (struct nl_handle *handle, struct genl_ops *ops)
int genl_mngt_resolve (struct nl_handle *handle)

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_register ( struct nl_cache_ops ops)
Parameters:
opscache operations

Definition at line 172 of file mngt.c.

References nl_cache_ops::co_msg_parser, nl_msgtype::mt_id, nl_msgtype::mt_name, and nl_cache_mngt_register().

{
int err;
if (ops->co_protocol != NETLINK_GENERIC) {
err = nl_error(EINVAL, "cache operations not for protocol " \
"NETLINK_GENERIC (protocol=%s)",
ops->co_protocol);
goto errout;
}
if (ops->co_hdrsize < GENL_HDRSIZE(0)) {
err = nl_error(EINVAL, "co_hdrsize too short, probably " \
"not including genlmsghdr, minsize=%d",
GENL_HDRSIZE(0));
goto errout;
}
if (ops->co_genl == NULL) {
err = nl_error(EINVAL, "co_genl is NULL, must provide " \
"valid genl operations");
goto errout;
}
ops->co_genl->o_cache_ops = ops;
ops->co_genl->o_name = ops->co_msgtypes[0].mt_name;
ops->co_genl->o_family = ops->co_msgtypes[0].mt_id;
ops->co_msg_parser = genl_msg_parser;
/* FIXME: check for dup */
nl_list_add_tail(&ops->co_genl->o_list, &genl_ops_list);
errout:
return err;
}
void genl_unregister ( struct nl_cache_ops ops)
Parameters:
opscache operations

Definition at line 214 of file mngt.c.

References nl_cache_mngt_unregister().

{
nl_list_del(&ops->co_genl->o_list);
}