Generic netlink has the ability to autoload modules in response to a request for
a family. Currently libnl uses a GETFAMILY call with the NLM_F_DUMP flag to
list all the available families, but doing so neglects the possibility of an
autoloaded module. This patch modifies the genl code to probe the kernel for a
specific family rather than dumping a list of all the currenlty available ones,
making autoload work properly.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Thomas Graf <tgraf@redhat.com>
Now the return value in case group id is not find is 0. Change it to
return -NLE_OBJ_NOTFOUND which makes more sense. This should not break
anything because genl_ctrl_grp_by_name is static and called only from
genl_ctrl_resolve_grp. genl_ctrl_resolve_grp already might return
-NLE_OBJ_NOTFOUND.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
I have a patch against commit d378220c96
extending libnl with a facility to receive generic netlink messages sent
to multicast groups.
Essentially it add one new function genl_ctrl_resolve_grp which
prototype looks like this
int genl_ctrl_resolve_grp(struct nl_sock *sk, const char *family_name,
const char *grp_name)
It resolves the family name and the group name to group id. Then
the returned id can be used in nl_socket_add_membership to subscribe
to multicast messages.
Besides that it adds two more functions
uint32_t nl_socket_get_peer_groups(struct nl_sock *sk)
void nl_socket_set_peer_groups(struct nl_sock *sk, uint32_t groups)
allowing to modify the socket peer groups field. So it's possible to
multicast messages from the user space using the legacy interface.
Looks like there is no way (or I was not able to find one?) to modify
the netlink socket destination group from the user space, when the
group id is greater then 32.
The idea of a common handle is long revised and only misleading,
nl_handle really represents a socket with some additional
action handlers assigned to it.
Alias for nl_handle is kept for backwards compatibility.
In order for the interface to become more thread safe, the error
handling was revised to no longer depend on a static errno and
error string buffer.
This patch converts all error paths to return a libnl specific
error code which can be translated to a error message using
nl_geterror(int error). The functions nl_error() and
nl_get_errno() are therefore obsolete.
This change required various sets of function prototypes to be
changed in order to return an error code, the most prominent
are:
struct nl_cache *foo_alloc_cache(...);
changed to:
int foo_alloc_cache(..., struct nl_cache **);
struct nl_msg *foo_build_request(...);
changed to:
int foo_build_request(..., struct nl_msg **);
struct foo *foo_parse(...);
changed to:
int foo_parse(..., struct foo **);
This pretty much only leaves trivial allocation functions to
still return a pointer object which can still return NULL to
signal out of memory.
This change is a serious API and ABI breaker, sorry!
Thomas Graf