xfrm: configure policy hash table thresholds by netlink

Enable to specify local and remote prefix length thresholds for the
policy hash table via a netlink XFRM_MSG_NEWSPDINFO message.

prefix length thresholds are specified by XFRMA_SPD_IPV4_HTHRESH and
XFRMA_SPD_IPV6_HTHRESH optional attributes (struct xfrmu_spdhthresh).

example:

    struct xfrmu_spdhthresh thresh4 = {
        .lbits = 0;
        .rbits = 24;
    };
    struct xfrmu_spdhthresh thresh6 = {
        .lbits = 0;
        .rbits = 56;
    };
    struct nlmsghdr *hdr;
    struct nl_msg *msg;

    msg = nlmsg_alloc();
    hdr = nlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, XFRMA_SPD_IPV4_HTHRESH, sizeof(__u32), NLM_F_REQUEST);
    nla_put(msg, XFRMA_SPD_IPV4_HTHRESH, sizeof(thresh4), &thresh4);
    nla_put(msg, XFRMA_SPD_IPV6_HTHRESH, sizeof(thresh6), &thresh6);
    nla_send_auto(sk, msg);

The numbers are the policy selector minimum prefix lengths to put a
policy in the hash table.

- lbits is the local threshold (source address for out policies,
  destination address for in and fwd policies).

- rbits is the remote threshold (destination address for out
  policies, source address for in and fwd policies).

The default values are:

XFRMA_SPD_IPV4_HTHRESH: 32 32
XFRMA_SPD_IPV6_HTHRESH: 128 128

Dynamic re-building of the SPD is performed when the thresholds values
are changed.

The current thresholds can be read via a XFRM_MSG_GETSPDINFO request:
the kernel replies to XFRM_MSG_GETSPDINFO requests by an
XFRM_MSG_NEWSPDINFO message, with both attributes
XFRMA_SPD_IPV4_HTHRESH and XFRMA_SPD_IPV6_HTHRESH.

Signed-off-by: Christophe Gouault <christophe.gouault@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Christophe Gouault
2014-08-29 16:16:05 +02:00
committed by Steffen Klassert
parent b58555f176
commit 880a6fab8f
5 changed files with 182 additions and 3 deletions

View File

@@ -566,6 +566,86 @@ static void xfrm_hash_resize(struct work_struct *work)
mutex_unlock(&hash_resize_mutex);
}
static void xfrm_hash_rebuild(struct work_struct *work)
{
struct net *net = container_of(work, struct net,
xfrm.policy_hthresh.work);
unsigned int hmask;
struct xfrm_policy *pol;
struct xfrm_policy *policy;
struct hlist_head *chain;
struct hlist_head *odst;
struct hlist_node *newpos;
int i;
int dir;
unsigned seq;
u8 lbits4, rbits4, lbits6, rbits6;
mutex_lock(&hash_resize_mutex);
/* read selector prefixlen thresholds */
do {
seq = read_seqbegin(&net->xfrm.policy_hthresh.lock);
lbits4 = net->xfrm.policy_hthresh.lbits4;
rbits4 = net->xfrm.policy_hthresh.rbits4;
lbits6 = net->xfrm.policy_hthresh.lbits6;
rbits6 = net->xfrm.policy_hthresh.rbits6;
} while (read_seqretry(&net->xfrm.policy_hthresh.lock, seq));
write_lock_bh(&net->xfrm.xfrm_policy_lock);
/* reset the bydst and inexact table in all directions */
for (dir = 0; dir < XFRM_POLICY_MAX * 2; dir++) {
INIT_HLIST_HEAD(&net->xfrm.policy_inexact[dir]);
hmask = net->xfrm.policy_bydst[dir].hmask;
odst = net->xfrm.policy_bydst[dir].table;
for (i = hmask; i >= 0; i--)
INIT_HLIST_HEAD(odst + i);
if ((dir & XFRM_POLICY_MASK) == XFRM_POLICY_OUT) {
/* dir out => dst = remote, src = local */
net->xfrm.policy_bydst[dir].dbits4 = rbits4;
net->xfrm.policy_bydst[dir].sbits4 = lbits4;
net->xfrm.policy_bydst[dir].dbits6 = rbits6;
net->xfrm.policy_bydst[dir].sbits6 = lbits6;
} else {
/* dir in/fwd => dst = local, src = remote */
net->xfrm.policy_bydst[dir].dbits4 = lbits4;
net->xfrm.policy_bydst[dir].sbits4 = rbits4;
net->xfrm.policy_bydst[dir].dbits6 = lbits6;
net->xfrm.policy_bydst[dir].sbits6 = rbits6;
}
}
/* re-insert all policies by order of creation */
list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) {
newpos = NULL;
chain = policy_hash_bysel(net, &policy->selector,
policy->family,
xfrm_policy_id2dir(policy->index));
hlist_for_each_entry(pol, chain, bydst) {
if (policy->priority >= pol->priority)
newpos = &pol->bydst;
else
break;
}
if (newpos)
hlist_add_behind(&policy->bydst, newpos);
else
hlist_add_head(&policy->bydst, chain);
}
write_unlock_bh(&net->xfrm.xfrm_policy_lock);
mutex_unlock(&hash_resize_mutex);
}
void xfrm_policy_hash_rebuild(struct net *net)
{
schedule_work(&net->xfrm.policy_hthresh.work);
}
EXPORT_SYMBOL(xfrm_policy_hash_rebuild);
/* Generate new index... KAME seems to generate them ordered by cost
* of an absolute inpredictability of ordering of rules. This will not pass. */
static u32 xfrm_gen_index(struct net *net, int dir, u32 index)
@@ -2872,9 +2952,16 @@ static int __net_init xfrm_policy_init(struct net *net)
htab->dbits6 = 128;
htab->sbits6 = 128;
}
net->xfrm.policy_hthresh.lbits4 = 32;
net->xfrm.policy_hthresh.rbits4 = 32;
net->xfrm.policy_hthresh.lbits6 = 128;
net->xfrm.policy_hthresh.rbits6 = 128;
seqlock_init(&net->xfrm.policy_hthresh.lock);
INIT_LIST_HEAD(&net->xfrm.policy_all);
INIT_WORK(&net->xfrm.policy_hash_work, xfrm_hash_resize);
INIT_WORK(&net->xfrm.policy_hthresh.work, xfrm_hash_rebuild);
if (net_eq(net, &init_net))
register_netdevice_notifier(&xfrm_dev_notifier);
return 0;