From 5492093dc4160d150890bc848c26ba7f8fff3094 Mon Sep 17 00:00:00 2001 From: David Miller Date: Tue, 28 Nov 2017 15:41:01 -0500 Subject: [PATCH] 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: David S. Miller Reviewed-by: Eric Dumazet --- net/xfrm/xfrm_policy.c | 56 ++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 24 deletions(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index da1b41ee4686..22e3350013b4 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -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; -- GitLab