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nhop: hash ifnet pointer instead of if_index

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Yet another problem created by VIMAGE/if_vmove/epair design that
relocates ifnet between vnets and changes if_index.  Since if_index
changes, nhop hash values also changes, unlink_nhop() isn't able to
find entry in hash and leaks the nhop.  Since nhop references ifnet,
the latter is also leaked.  As result running network tests leaks
memory on every single test that creates vnet jail.

While here, rewrite whole hash_priv() to use static initializer,
per Alexander's suggestion.

Reviewed by:	melifaro
This commit is contained in:
Gleb Smirnoff 2021-12-04 10:05:46 -08:00
parent c2b53b107e
commit ad2a0aec29
1 changed files with 12 additions and 18 deletions
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30
sys/net/route/nhop.c
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@ -183,13 +183,13 @@ nhops_destroy_rib(struct rib_head *rh)
* With that in mind, hash nexthops by the combination of the interface
* and GW IP address.
*
* To optimize hash calculation, ignore higher bytes of ifindex, as they
* give very little entropy.
* To optimize hash calculation, ignore lower bits of ifnet pointer,
* as they give very little entropy.
* Similarly, use lower 4 bytes of IPv6 address to distinguish between the
* neighbors.
*/
struct _hash_data {
uint16_t ifindex;
uint16_t ifentropy;
uint8_t family;
uint8_t nh_type;
uint32_t gw_addr;
@ -210,21 +210,15 @@ djb_hash(const unsigned char *h, const int len)
static uint32_t
hash_priv(const struct nhop_priv *priv)
{
struct nhop_object *nh;
uint16_t ifindex;
struct _hash_data key;
nh = priv->nh;
ifindex = nh->nh_ifp->if_index & 0xFFFF;
memset(&key, 0, sizeof(key));
key.ifindex = ifindex;
key.family = nh->gw_sa.sa_family;
key.nh_type = priv->nh_type & 0xFF;
if (nh->gw_sa.sa_family == AF_INET6)
memcpy(&key.gw_addr, &nh->gw6_sa.sin6_addr.s6_addr32[3], 4);
else if (nh->gw_sa.sa_family == AF_INET)
memcpy(&key.gw_addr, &nh->gw4_sa.sin_addr, 4);
struct nhop_object *nh = priv->nh;
struct _hash_data key = {
.ifentropy = (uint16_t)((((uintptr_t)nh->nh_ifp) >> 6) & 0xFFFF),
.family = nh->gw_sa.sa_family,
.nh_type = priv->nh_type & 0xFF,
.gw_addr = (nh->gw_sa.sa_family == AF_INET6) ?
nh->gw6_sa.sin6_addr.s6_addr32[3] :
nh->gw4_sa.sin_addr.s_addr
};
return (uint32_t)(djb_hash((const unsigned char *)&key, sizeof(key)));
}