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nl80211: Retrieve maxattr via genl for nl80211

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Older kernel versions may not support all attributes and may refuse
commands that include them. To avoid sending too new attributes query
the highest supported attribute. This allows adding appropriate checks
where needed.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
This commit is contained in:
Benjamin Berg 2023-12-28 15:14:05 +02:00 committed by Jouni Malinen
parent f136837202
commit 7fec9e7bc1
2 changed files with 29 additions and 0 deletions
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28
src/drivers/driver_nl80211.c
View file

@ -16,6 +16,7 @@
#include <net/if.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/ctrl.h>
#include <netlink/genl/family.h>
#ifdef CONFIG_LIBNL3_ROUTE
#include <netlink/route/neighbour.h>
#endif /* CONFIG_LIBNL3_ROUTE */
@ -1938,6 +1939,8 @@ static int wpa_driver_nl80211_get_country(void *priv, char *alpha2)
static int wpa_driver_nl80211_init_nl_global(struct nl80211_global *global)
{
struct nl_cache *cache = NULL;
struct genl_family *family = NULL;
int ret;
global->nl_cb = nl_cb_alloc(NL_CB_DEFAULT);
@ -2009,6 +2012,29 @@ static int wpa_driver_nl80211_init_nl_global(struct nl80211_global *global)
/* Continue without vendor events */
}
/* Resolve maxattr for kernel support checks */
ret = genl_ctrl_alloc_cache(global->nl, &cache);
if (ret < 0) {
wpa_printf(MSG_DEBUG,
"nl80211: Could not allocate genl cache: %d (%s)",
ret, nl_geterror(ret));
goto err;
}
family = genl_ctrl_search(cache, global->nl80211_id);
if (!family) {
wpa_printf(MSG_DEBUG,
"nl80211: Could not get nl80211 family from cache: %d (%s)",
ret, nl_geterror(ret));
goto err;
}
global->nl80211_maxattr = genl_family_get_maxattr(family);
wpa_printf(MSG_DEBUG, "nl80211: Maximum supported attribute ID: %u",
global->nl80211_maxattr);
genl_family_put(family);
nl_cache_free(cache);
nl_cb_set(global->nl_cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM,
no_seq_check, NULL);
nl_cb_set(global->nl_cb, NL_CB_VALID, NL_CB_CUSTOM,
@ -2021,6 +2047,8 @@ static int wpa_driver_nl80211_init_nl_global(struct nl80211_global *global)
return 0;
err:
genl_family_put(family);
nl_cache_free(cache);
nl_destroy_handles(&global->nl_event);
nl_destroy_handles(&global->nl);
nl_cb_put(global->nl_cb);

1
src/drivers/driver_nl80211.h
View file

@ -32,6 +32,7 @@ struct nl80211_global {
struct nl_cb *nl_cb;
struct nl_sock *nl;
int nl80211_id;
unsigned int nl80211_maxattr;
int nlctrl_id;
int ioctl_sock; /* socket for ioctl() use */