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netlink: ensure genetlink control family always registers under the same ID.

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MFC after:	2 weeks
This commit is contained in:
Alexander V. Chernikov 2023-03-27 10:48:24 +00:00 committed by Oscar Zhao
parent 48a1ce8157
commit b1f88e8e66
1 changed files with 36 additions and 16 deletions
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52
sys/netlink/netlink_generic.c
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@ -47,6 +47,8 @@ __FBSDID("$FreeBSD$");
#include <netlink/netlink_debug.h>
_DECLARE_DEBUG(LOG_DEBUG);
#define CTRL_FAMILY_NAME "nlctrl"
#define MAX_FAMILIES 20
#define MAX_GROUPS 64
@ -96,6 +98,28 @@ find_family(const char *family_name)
return (NULL);
}
static struct genl_family *
find_empty_family_id(const char *family_name)
{
struct genl_family *gf = NULL;
if (!strcmp(family_name, CTRL_FAMILY_NAME)) {
gf = &families[0];
gf->family_id = GENL_MIN_ID;
} else {
/* Index 0 is reserved for the control family */
for (int i = 1; i < MAX_FAMILIES; i++) {
struct genl_family *gf = &families[i];
if (gf->family_name == NULL) {
gf->family_id = GENL_MIN_ID + i;
break;
}
}
}
return (gf);
}
uint32_t
genl_register_family(const char *family_name, size_t hdrsize, int family_version,
int max_attr_idx)
@ -107,21 +131,18 @@ genl_register_family(const char *family_name, size_t hdrsize, int family_version
return (0);
GENL_LOCK();
for (int i = 0; i < MAX_FAMILIES; i++) {
struct genl_family *gf = &families[i];
if (gf->family_name == NULL) {
gf->family_name = family_name;
gf->family_version = family_version;
gf->family_hdrsize = hdrsize;
gf->family_attr_max = max_attr_idx;
gf->family_id = i + GENL_MIN_ID;
NL_LOG(LOG_DEBUG2, "Registered family %s id %d",
gf->family_name, gf->family_id);
family_id = gf->family_id;
nlctrl_notify(gf, CTRL_CMD_NEWFAMILY);
break;
}
}
struct genl_family *gf = find_empty_family_id(family_name);
MPASS(gf != NULL);
gf->family_name = family_name;
gf->family_version = family_version;
gf->family_hdrsize = hdrsize;
gf->family_attr_max = max_attr_idx;
NL_LOG(LOG_DEBUG2, "Registered family %s id %d", gf->family_name, gf->family_id);
family_id = gf->family_id;
nlctrl_notify(gf, CTRL_CMD_NEWFAMILY);
GENL_UNLOCK();
return (family_id);
@ -377,7 +398,6 @@ dump_family(struct nlmsghdr *hdr, struct genlmsghdr *ghdr,
/* Declare ourself as a user */
#define CTRL_FAMILY_NAME "nlctrl"
static uint32_t ctrl_family_id;
static uint32_t ctrl_group_id;