[XFRM]: Extension for dynamic update of endpoint address(es)

Extend the XFRM framework so that endpoint address(es) in the XFRM
databases could be dynamically updated according to a request (MIGRATE
message) from user application. Target XFRM policy is first identified
by the selector in the MIGRATE message. Next, the endpoint addresses
of the matching templates and XFRM states are updated according to
the MIGRATE message.

Signed-off-by: Shinta Sugimoto <shinta.sugimoto@ericsson.com>
Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 230 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index b7e537fe2d75..825c60af7723 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2236,3 +2236,233 @@ void __init xfrm_init(void)
         xfrm_input_init();
 }
 
+#ifdef CONFIG_XFRM_MIGRATE
+static int xfrm_migrate_selector_match(struct xfrm_selector *sel_cmp,
+                                       struct xfrm_selector *sel_tgt)
+{
+        if (sel_cmp->proto == IPSEC_ULPROTO_ANY) {
+                if (sel_tgt->family == sel_cmp->family &&
+                    xfrm_addr_cmp(&sel_tgt->daddr, &sel_cmp->daddr,
+                                  sel_cmp->family) == 0 &&
+                    xfrm_addr_cmp(&sel_tgt->saddr, &sel_cmp->saddr,
+                                  sel_cmp->family) == 0 &&
+                    sel_tgt->prefixlen_d == sel_cmp->prefixlen_d &&
+                    sel_tgt->prefixlen_s == sel_cmp->prefixlen_s) {
+                        return 1;
+                }
+        } else {
+                if (memcmp(sel_tgt, sel_cmp, sizeof(*sel_tgt)) == 0) {
+                        return 1;
+                }
+        }
+        return 0;
+}
+
+static struct xfrm_policy * xfrm_migrate_policy_find(struct xfrm_selector *sel,
+                                                     u8 dir, u8 type)
+{
+        struct xfrm_policy *pol, *ret = NULL;
+        struct hlist_node *entry;
+        struct hlist_head *chain;
+        u32 priority = ~0U;
+
+        read_lock_bh(&xfrm_policy_lock);
+        chain = policy_hash_direct(&sel->daddr, &sel->saddr, sel->family, dir);
+        hlist_for_each_entry(pol, entry, chain, bydst) {
+                if (xfrm_migrate_selector_match(sel, &pol->selector) &&
+                    pol->type == type) {
+                        ret = pol;
+                        priority = ret->priority;
+                        break;
+                }
+        }
+        chain = &xfrm_policy_inexact[dir];
+        hlist_for_each_entry(pol, entry, chain, bydst) {
+                if (xfrm_migrate_selector_match(sel, &pol->selector) &&
+                    pol->type == type &&
+                    pol->priority < priority) {
+                        ret = pol;
+                        break;
+                }
+        }
+
+        if (ret)
+                xfrm_pol_hold(ret);
+
+        read_unlock_bh(&xfrm_policy_lock);
+
+        return ret;
+}
+
+static int migrate_tmpl_match(struct xfrm_migrate *m, struct xfrm_tmpl *t)
+{
+        int match = 0;
+
+        if (t->mode == m->mode && t->id.proto == m->proto &&
+            (m->reqid == 0 || t->reqid == m->reqid)) {
+                switch (t->mode) {
+                case XFRM_MODE_TUNNEL:
+                case XFRM_MODE_BEET:
+                        if (xfrm_addr_cmp(&t->id.daddr, &m->old_daddr,
+                                          m->old_family) == 0 &&
+                            xfrm_addr_cmp(&t->saddr, &m->old_saddr,
+                                          m->old_family) == 0) {
+                                match = 1;
+                        }
+                        break;
+                case XFRM_MODE_TRANSPORT:
+                        /* in case of transport mode, template does not store
+                           any IP addresses, hence we just compare mode and
+                           protocol */
+                        match = 1;
+                        break;
+                default:
+                        break;
+                }
+        }
+        return match;
+}
+
+/* update endpoint address(es) of template(s) */
+static int xfrm_policy_migrate(struct xfrm_policy *pol,
+                               struct xfrm_migrate *m, int num_migrate)
+{
+        struct xfrm_migrate *mp;
+        struct dst_entry *dst;
+        int i, j, n = 0;
+
+        write_lock_bh(&pol->lock);
+        if (unlikely(pol->dead)) {
+                /* target policy has been deleted */
+                write_unlock_bh(&pol->lock);
+                return -ENOENT;
+        }
+
+        for (i = 0; i < pol->xfrm_nr; i++) {
+                for (j = 0, mp = m; j < num_migrate; j++, mp++) {
+                        if (!migrate_tmpl_match(mp, &pol->xfrm_vec[i]))
+                                continue;
+                        n++;
+                        if (pol->xfrm_vec[i].mode != XFRM_MODE_TUNNEL)
+                                continue;
+                        /* update endpoints */
+                        memcpy(&pol->xfrm_vec[i].id.daddr, &mp->new_daddr,
+                               sizeof(pol->xfrm_vec[i].id.daddr));
+                        memcpy(&pol->xfrm_vec[i].saddr, &mp->new_saddr,
+                               sizeof(pol->xfrm_vec[i].saddr));
+                        pol->xfrm_vec[i].encap_family = mp->new_family;
+                        /* flush bundles */
+                        while ((dst = pol->bundles) != NULL) {
+                                pol->bundles = dst->next;
+                                dst_free(dst);
+                        }
+                }
+        }
+
+        write_unlock_bh(&pol->lock);
+
+        if (!n)
+                return -ENODATA;
+
+        return 0;
+}
+
+static int xfrm_migrate_check(struct xfrm_migrate *m, int num_migrate)
+{
+        int i, j;
+
+        if (num_migrate < 1 || num_migrate > XFRM_MAX_DEPTH)
+                return -EINVAL;
+
+        for (i = 0; i < num_migrate; i++) {
+                if ((xfrm_addr_cmp(&m[i].old_daddr, &m[i].new_daddr,
+                                   m[i].old_family) == 0) &&
+                    (xfrm_addr_cmp(&m[i].old_saddr, &m[i].new_saddr,
+                                   m[i].old_family) == 0))
+                        return -EINVAL;
+                if (xfrm_addr_any(&m[i].new_daddr, m[i].new_family) ||
+                    xfrm_addr_any(&m[i].new_saddr, m[i].new_family))
+                        return -EINVAL;
+
+                /* check if there is any duplicated entry */
+                for (j = i + 1; j < num_migrate; j++) {
+                        if (!memcmp(&m[i].old_daddr, &m[j].old_daddr,
+                                    sizeof(m[i].old_daddr)) &&
+                            !memcmp(&m[i].old_saddr, &m[j].old_saddr,
+                                    sizeof(m[i].old_saddr)) &&
+                            m[i].proto == m[j].proto &&
+                            m[i].mode == m[j].mode &&
+                            m[i].reqid == m[j].reqid &&
+                            m[i].old_family == m[j].old_family)
+                                return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
+int xfrm_migrate(struct xfrm_selector *sel, u8 dir, u8 type,
+                 struct xfrm_migrate *m, int num_migrate)
+{
+        int i, err, nx_cur = 0, nx_new = 0;
+        struct xfrm_policy *pol = NULL;
+        struct xfrm_state *x, *xc;
+        struct xfrm_state *x_cur[XFRM_MAX_DEPTH];
+        struct xfrm_state *x_new[XFRM_MAX_DEPTH];
+        struct xfrm_migrate *mp;
+
+        if ((err = xfrm_migrate_check(m, num_migrate)) < 0)
+                goto out;
+
+        /* Stage 1 - find policy */
+        if ((pol = xfrm_migrate_policy_find(sel, dir, type)) == NULL) {
+                err = -ENOENT;
+                goto out;
+        }
+
+        /* Stage 2 - find and update state(s) */
+        for (i = 0, mp = m; i < num_migrate; i++, mp++) {
+                if ((x = xfrm_migrate_state_find(mp))) {
+                        x_cur[nx_cur] = x;
+                        nx_cur++;
+                        if ((xc = xfrm_state_migrate(x, mp))) {
+                                x_new[nx_new] = xc;
+                                nx_new++;
+                        } else {
+                                err = -ENODATA;
+                                goto restore_state;
+                        }
+                }
+        }
+
+        /* Stage 3 - update policy */
+        if ((err = xfrm_policy_migrate(pol, m, num_migrate)) < 0)
+                goto restore_state;
+
+        /* Stage 4 - delete old state(s) */
+        if (nx_cur) {
+                xfrm_states_put(x_cur, nx_cur);
+                xfrm_states_delete(x_cur, nx_cur);
+        }
+
+        /* Stage 5 - announce */
+        km_migrate(sel, dir, type, m, num_migrate);
+
+        xfrm_pol_put(pol);
+
+        return 0;
+out:
+        return err;
+
+restore_state:
+        if (pol)
+                xfrm_pol_put(pol);
+        if (nx_cur)
+                xfrm_states_put(x_cur, nx_cur);
+        if (nx_new)
+                xfrm_states_delete(x_new, nx_new);
+
+        return err;
+}
+#endif
+