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[Generic Netlink]

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)

 // ... respectively unregsted again.
 static void __exit foo_exit(void)




struct  genl_cmd
struct  genl_ops

Resolving ID/Name

static int __genl_ops_resolve (struct nl_cache *ctrl, struct genl_ops *ops)
int genl_mngt_resolve (struct nl_sock *sk)
int genl_ops_resolve (struct nl_sock *sk, struct genl_ops *ops)


int genl_register (struct nl_cache_ops *ops)
void genl_unregister (struct nl_cache_ops *ops)


static int genl_msg_parser (struct nl_cache_ops *ops, struct sockaddr_nl *who, struct nlmsghdr *nlh, struct nl_parser_param *pp)
char * genl_op2name (int family, int op, char *buf, size_t len)
static NL_LIST_HEAD (genl_ops_list)

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