staticd: refcount the nht add/removal

When we add / remove a nexthop that we need to track,
keep track of the number of times we have done this
for each nexthop.  Consequently keep track of the
number of available nexthops, so that we can
just install new routes when we get one
that uses a pre-existing nexthop.  Deletion of
nexthops is done on refcount going to 0.
Removal of routes is handled elsewhere for removal.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

diff --git a/staticd/static_zebra.c b/staticd/static_zebra.c
index 56ba70eaf8a1aa5c75f7c363d80387a60eaf4c5e..a87dc074dfc07e2d5f1bfcd41adae3917dc2dde2 100644 (file)
--- a/staticd/static_zebra.c
+++ b/staticd/static_zebra.c
@@ -34,6 +34,7 @@
 #include "log.h"
 #include "nexthop.h"
 #include "nexthop_group.h"
+#include "hash.h"
 
 #include "static_vrf.h"
 #include "static_routes.h"
@@ -43,6 +44,7 @@
 
 /* Zebra structure to hold current status. */
 struct zclient *zclient;
+static struct hash *static_nht_hash;
 
 static struct interface *zebra_interface_if_lookup(struct stream *s)
 {
@@ -176,10 +178,16 @@ static void zebra_connected(struct zclient *zclient)
        zclient_send_reg_requests(zclient, VRF_DEFAULT);
 }
 
+struct static_nht_data {
+       struct prefix *nh;
+       uint32_t refcount;
+       uint8_t nh_num;
+};
 
 static int static_zebra_nexthop_update(int command, struct zclient *zclient,
                                       zebra_size_t length, vrf_id_t vrf_id)
 {
+       struct static_nht_data *nhtd, lookup;
        struct zapi_route nhr;
        afi_t afi = AFI_IP;
 
@@ -191,6 +199,14 @@ static int static_zebra_nexthop_update(int command, struct zclient *zclient,
        if (nhr.prefix.family == AF_INET6)
                afi = AFI_IP6;
 
+       memset(&lookup, 0, sizeof(lookup));
+       lookup.nh = &nhr.prefix;
+
+       nhtd = hash_lookup(static_nht_hash, &lookup);
+       if (nhtd)
+               nhtd->nh_num = nhr.nexthop_num;
+
+
        static_nht_update(&nhr.prefix, nhr.nexthop_num, afi, vrf_id);
        return 1;
 }
@@ -200,10 +216,50 @@ static void static_zebra_capabilities(struct zclient_capabilities *cap)
        mpls_enabled = cap->mpls_enabled;
 }
 
+static unsigned int static_nht_hash_key(void *data)
+{
+       struct static_nht_data *nhtd = data;
+
+       return prefix_hash_key(nhtd->nh);
+}
+
+static int static_nht_hash_cmp(const void *d1, const void *d2)
+{
+       const struct static_nht_data *nhtd1 = d1;
+       const struct static_nht_data *nhtd2 = d2;
+
+       return prefix_same(nhtd1->nh, nhtd2->nh);
+}
+
+static void *static_nht_hash_alloc(void *data)
+{
+       struct static_nht_data *copy = data;
+       struct static_nht_data *new;
+
+       new = XMALLOC(MTYPE_TMP, sizeof(*new));
+
+       new->nh = prefix_new();
+       prefix_copy(new->nh, copy->nh);
+       new->refcount = 0;
+       new->nh_num = 0;
+
+       return new;
+}
+
+static void static_nht_hash_free(void *data)
+{
+       struct static_nht_data *nhtd = data;
+
+       prefix_free(nhtd->nh);
+       XFREE(MTYPE_TMP, nhtd);
+}
+
 void static_zebra_nht_register(struct static_route *si, bool reg)
 {
+       struct static_nht_data *nhtd, lookup;
        uint32_t cmd;
        struct prefix p;
+       afi_t afi = AFI_IP;
 
        cmd = (reg) ?
                ZEBRA_NEXTHOP_REGISTER : ZEBRA_NEXTHOP_UNREGISTER;
@@ -224,20 +280,48 @@ void static_zebra_nht_register(struct static_route *si, bool reg)
                p.family = AF_INET;
                p.prefixlen = IPV4_MAX_BITLEN;
                p.u.prefix4 = si->addr.ipv4;
+               afi = AFI_IP;
                break;
        case STATIC_IPV6_GATEWAY:
        case STATIC_IPV6_GATEWAY_IFNAME:
                p.family = AF_INET6;
                p.prefixlen = IPV6_MAX_BITLEN;
                p.u.prefix6 = si->addr.ipv6;
+               afi = AFI_IP6;
                break;
        }
 
+       memset(&lookup, 0, sizeof(lookup));
+       lookup.nh = &p;
+
+       si->nh_registered = reg;
+
+       if (reg) {
+               nhtd = hash_get(static_nht_hash, &lookup,
+                               static_nht_hash_alloc);
+               nhtd->refcount++;
+
+               if (nhtd->refcount > 1) {
+                       static_nht_update(nhtd->nh, nhtd->nh_num,
+                                         afi, si->nh_vrf_id);
+                       return;
+               }
+       } else {
+               nhtd = hash_lookup(static_nht_hash, &lookup);
+               if (!nhtd)
+                       return;
+
+               nhtd->refcount--;
+               if (nhtd->refcount >= 1)
+                       return;
+
+               hash_release(static_nht_hash, nhtd);
+               static_nht_hash_free(nhtd);
+       }
+
        if (zclient_send_rnh(zclient, cmd, &p, false, si->nh_vrf_id) < 0)
                zlog_warn("%s: Failure to send nexthop to zebra",
                          __PRETTY_FUNCTION__);
-
-       si->nh_registered = reg;
 }
 
 extern void static_zebra_route_add(struct route_node *rn,
@@ -373,4 +457,8 @@ void static_zebra_init(void)
        zclient->interface_address_delete = interface_address_delete;
        zclient->route_notify_owner = route_notify_owner;
        zclient->nexthop_update = static_zebra_nexthop_update;
+
+       static_nht_hash = hash_create(static_nht_hash_key,
+                                     static_nht_hash_cmp,
+                                     "Static Nexthop Tracking hash");
 }