Commit 5492093d authored by David Miller's avatar David Miller Committed by David S. Miller
Browse files

xfrm: Stop using dst->next in bundle construction. 



While building ipsec bundles, blocks of xfrm dsts are linked together
using dst->next from bottom to the top.

The only thing this is used for is initializing the pmtu values of the
xfrm stack, and for updating the mtu values at xfrm_bundle_ok() time.

The bundle pmtu entries must be processed in this order so that pmtu
values lower in the stack of routes can propagate up to the higher
ones.

Avoid using dst->next by simply maintaining an array of dst pointers
as we already do for the xfrm_state objects when building the bundle.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
parent 8b207e73

net/xfrm/xfrm_policy.c

+32 −24
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ static struct xfrm_policy_afinfo const __rcu *xfrm_policy_afinfo[AF_INET6 + 1] 
static struct kmem_cache *xfrm_dst_cache __read_mostly;

static __read_mostly seqcount_t xfrm_policy_hash_generation;



static void xfrm_init_pmtu(struct dst_entry *dst);

static void xfrm_init_pmtu(struct xfrm_dst **bundle, int nr);

static int stale_bundle(struct dst_entry *dst);

static int xfrm_bundle_ok(struct xfrm_dst *xdst);

static void xfrm_policy_queue_process(struct timer_list *t);
@@ -1538,7 +1538,9 @@ static inline int xfrm_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 
 */



static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,

					    struct xfrm_state **xfrm, int nx,

					    struct xfrm_state **xfrm,

					    struct xfrm_dst **bundle,

					    int nx,

					    const struct flowi *fl,

					    struct dst_entry *dst)

{
@@ -1573,6 +1575,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, 
			goto put_states;

		}



		bundle[i] = xdst;

		if (!xdst_prev)

			xdst0 = xdst;

		else
@@ -1616,7 +1619,6 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, 
		dst1->input = dst_discard;

		dst1->output = inner_mode->afinfo->output;



		dst1->next = &xdst_prev->u.dst;

		xdst_prev = xdst;



		header_len += xfrm[i]->props.header_len;
@@ -1634,7 +1636,7 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy, 
		goto free_dst;



	xfrm_init_path(xdst0, dst, nfheader_len);

	xfrm_init_pmtu(&xdst_prev->u.dst);

	xfrm_init_pmtu(bundle, nx);



	for (xdst_prev = xdst0; xdst_prev != (struct xfrm_dst *)dst;

	     xdst_prev = (struct xfrm_dst *) xfrm_dst_child(&xdst_prev->u.dst)) {
@@ -1812,6 +1814,7 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols, 
{

	struct net *net = xp_net(pols[0]);

	struct xfrm_state *xfrm[XFRM_MAX_DEPTH];

	struct xfrm_dst *bundle[XFRM_MAX_DEPTH];

	struct xfrm_dst *xdst, *old;

	struct dst_entry *dst;

	int err;
@@ -1839,7 +1842,7 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols, 


	old = xdst;



	dst = xfrm_bundle_create(pols[0], xfrm, err, fl, dst_orig);

	dst = xfrm_bundle_create(pols[0], xfrm, bundle, err, fl, dst_orig);

	if (IS_ERR(dst)) {

		XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLEGENERROR);

		return ERR_CAST(dst);
@@ -2599,12 +2602,14 @@ static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst) 
	return dst;

}



static void xfrm_init_pmtu(struct dst_entry *dst)

static void xfrm_init_pmtu(struct xfrm_dst **bundle, int nr)

{

	do {

		struct xfrm_dst *xdst = (struct xfrm_dst *)dst;

	while (nr--) {

		struct xfrm_dst *xdst = bundle[nr];

		u32 pmtu, route_mtu_cached;

		struct dst_entry *dst;



		dst = &xdst->u.dst;

		pmtu = dst_mtu(xfrm_dst_child(dst));

		xdst->child_mtu_cached = pmtu;
@@ -2617,7 +2622,7 @@ static void xfrm_init_pmtu(struct dst_entry *dst) 
			pmtu = route_mtu_cached;



		dst_metric_set(dst, RTAX_MTU, pmtu);

	} while ((dst = dst->next));

	}

}



/* Check that the bundle accepts the flow and its components are
@@ -2626,8 +2631,10 @@ static void xfrm_init_pmtu(struct dst_entry *dst) 


static int xfrm_bundle_ok(struct xfrm_dst *first)

{

	struct xfrm_dst *bundle[XFRM_MAX_DEPTH];

	struct dst_entry *dst = &first->u.dst;

	struct xfrm_dst *last;

	struct xfrm_dst *xdst;

	int start_from, nr;

	u32 mtu;



	if (!dst_check(xfrm_dst_path(dst), ((struct xfrm_dst *)dst)->path_cookie) ||
@@ -2637,8 +2644,7 @@ static int xfrm_bundle_ok(struct xfrm_dst *first) 
	if (dst->flags & DST_XFRM_QUEUE)

		return 1;



	last = NULL;



	start_from = nr = 0;

	do {

		struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
@@ -2650,9 +2656,11 @@ static int xfrm_bundle_ok(struct xfrm_dst *first) 
		    xdst->policy_genid != atomic_read(&xdst->pols[0]->genid))

			return 0;



		bundle[nr++] = xdst;



		mtu = dst_mtu(xfrm_dst_child(dst));

		if (xdst->child_mtu_cached != mtu) {

			last = xdst;

			start_from = nr;

			xdst->child_mtu_cached = mtu;

		}
@@ -2660,30 +2668,30 @@ static int xfrm_bundle_ok(struct xfrm_dst *first) 
			return 0;

		mtu = dst_mtu(xdst->route);

		if (xdst->route_mtu_cached != mtu) {

			last = xdst;

			start_from = nr;

			xdst->route_mtu_cached = mtu;

		}



		dst = xfrm_dst_child(dst);

	} while (dst->xfrm);



	if (likely(!last))

	if (likely(!start_from))

		return 1;



	mtu = last->child_mtu_cached;

	for (;;) {

		dst = &last->u.dst;

	xdst = bundle[start_from - 1];

	mtu = xdst->child_mtu_cached;

	while (start_from--) {

		dst = &xdst->u.dst;



		mtu = xfrm_state_mtu(dst->xfrm, mtu);

		if (mtu > last->route_mtu_cached)

			mtu = last->route_mtu_cached;

		if (mtu > xdst->route_mtu_cached)

			mtu = xdst->route_mtu_cached;

		dst_metric_set(dst, RTAX_MTU, mtu);



		if (last == first)

		if (!start_from)

			break;



		last = (struct xfrm_dst *)last->u.dst.next;

		last->child_mtu_cached = mtu;

		xdst = bundle[start_from - 1];

		xdst->child_mtu_cached = mtu;

	}



	return 1;

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