batman-adv: add bat_neigh_is_equiv_or_better API function

Each routing protocol has its own metric semantic and
therefore is the protocol itself the only component able to
compare two metrics to check their "similarity".

This new API allows each routing protocol to implement its
own logic and make the external code protocol agnostic.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index b288d90855d16f373a76253683d245b6196982f8..4376fe75eeec5bb7d805f6ffde2d67938f3d1b02 100644 (file)
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1494,6 +1494,23 @@ static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
        return tq1 - tq2;
 }
 
+/**
+ * batadv_iv_ogm_neigh_is_eob - check if neigh1 is equally good or better than
+ *  neigh2 from the metric prospective
+ * @neigh1: the first neighbor object of the comparison
+ * @neigh2: the second neighbor object of the comparison
+ *
+ * Returns true if the metric via neigh1 is equally good or better than the
+ * metric via neigh2, false otherwise.
+ */
+static bool batadv_iv_ogm_neigh_is_eob(struct batadv_neigh_node *neigh1,
+                                      struct batadv_neigh_node *neigh2)
+{
+       int diff = batadv_iv_ogm_neigh_cmp(neigh1, neigh2);
+
+       return diff > -BATADV_TQ_SIMILARITY_THRESHOLD;
+}
+
 static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
        .name = "BATMAN_IV",
        .bat_iface_enable = batadv_iv_ogm_iface_enable,
@@ -1503,6 +1520,7 @@ static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
        .bat_ogm_schedule = batadv_iv_ogm_schedule,
        .bat_ogm_emit = batadv_iv_ogm_emit,
        .bat_neigh_cmp = batadv_iv_ogm_neigh_cmp,
+       .bat_neigh_is_equiv_or_better = batadv_iv_ogm_neigh_is_eob,
        .bat_orig_print = batadv_iv_ogm_orig_print,
 };
 

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 1f2f1ac67a4cb3af930e0ddf555112e6fe09c022..c51a5e568f0a80c08beb4ded5b34b1aff8d5cfdf 100644 (file)
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -502,7 +502,8 @@ int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops)
            !bat_algo_ops->bat_primary_iface_set ||
            !bat_algo_ops->bat_ogm_schedule ||
            !bat_algo_ops->bat_ogm_emit ||
-           !bat_algo_ops->bat_neigh_cmp) {
+           !bat_algo_ops->bat_neigh_cmp ||
+           !bat_algo_ops->bat_neigh_is_equiv_or_better) {
                pr_info("Routing algo '%s' does not implement required ops\n",
                        bat_algo_ops->name);
                ret = -EINVAL;

diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index d7dfafe45f2901e41cca4a3d312331e72da013ff..773301a7923febbb7d366bce3fbcaf15beeb4d86 100644 (file)
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -86,6 +86,12 @@
 /* numbers of originator to contact for any PUT/GET DHT operation */
 #define BATADV_DAT_CANDIDATES_NUM 3
 
+/**
+ * BATADV_TQ_SIMILARITY_THRESHOLD - TQ points that a secondary metric can differ
+ *  at most from the primary one in order to be still considered acceptable
+ */
+#define BATADV_TQ_SIMILARITY_THRESHOLD 50
+
 /* how much worse secondary interfaces may be to be considered as bonding
  * candidates
  */

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 7a00932a55bd305c41adc95adb58ec64eb910ef0..d0e64d269da40667f8cca11631dc0bf1cca5fba6 100644 (file)
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -993,6 +993,8 @@ struct batadv_forw_packet {
  * @bat_ogm_schedule: prepare a new outgoing OGM for the send queue
  * @bat_ogm_emit: send scheduled OGM
  * @bat_neigh_cmp: compare the metrics of two neighbors
+ * @bat_neigh_is_equiv_or_better: check if neigh1 is equally good or
+ *  better than neigh2 from the metric prospective
  * @bat_orig_print: print the originator table (optional)
  */
 struct batadv_algo_ops {
@@ -1006,6 +1008,8 @@ struct batadv_algo_ops {
        void (*bat_ogm_emit)(struct batadv_forw_packet *forw_packet);
        int (*bat_neigh_cmp)(struct batadv_neigh_node *neigh1,
                             struct batadv_neigh_node *neigh2);
+       bool (*bat_neigh_is_equiv_or_better)(struct batadv_neigh_node *neigh1,
+                                            struct batadv_neigh_node *neigh2);
        /* orig_node handling API */
        void (*bat_orig_print)(struct batadv_priv *priv, struct seq_file *seq);
 };