"-" was never used in the names of the flags. "_" was used in all places
of the library. So, I just changed the undescore to the minus.
Automatic indentation can insert spaces on either side of the minus,
so the library will be compiled, but will not be usable (in this part of the code),
as the parser will split words by white space, and the flag "admin - perm"
will never work.
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.
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