interface: add prefix assignment priority support

In case of prefix delegation prefixes are assigned to one or more
configured downstream interfaces. The delegated prefix length in
combination with the assignment length of the downstream interfaces
determines the number of subnets which can be allocated from the
delegated prefix.
The interface ip6weight parameter allows to prioritize the allocation
of subnets to interfaces in case of multiple configured downstream
interfaces.

The order of interface prefix assignment from a delegated prefix is
based on the following parameters:
- Primary key is prefix assignment based on the configured interface ip6hint
- Secondary key is the requested downstream interface prefix length,
  interfaces configured with the smallest ip6hint will be assigned first
- Third key is the assigned interface ip6weight in case of equal prefix
  assignment length; interfaces having the highest ip6weight will be
  assigned first
- Finally the alphabetical order of the interfaces in case of equal
  ip6weight

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [cleanup]

diff --git a/interface-ip.c b/interface-ip.c
index f8dab840490981a2793226b8a4df862d906d4b3b..ddca5d2e8dfc27564f8486d9908e2fcf934c89e9 100644 (file)
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -850,6 +850,25 @@ static bool interface_prefix_assign(struct list_head *list,
        return false;
 }
 
+/*
+ * Sorting of assignment entries:
+ * Primary on assignment length: smallest assignment first
+ * Secondary on assignment weight: highest weight first
+ * Finally alphabetical order of interface names
+ */
+static int prefix_assignment_cmp(const void *k1, const void *k2, void *ptr)
+{
+       const struct device_prefix_assignment *a1 = k1, *a2 = k2;
+
+       if (a1->length != a2->length)
+               return a1->length - a2->length;
+
+       if (a1->weight != a2->weight)
+               return a2->weight - a1->weight;
+
+       return strcmp(a1->name, a2->name);
+}
+
 static void interface_update_prefix_assignments(struct device_prefix *prefix, bool setup)
 {
        struct device_prefix_assignment *c;
@@ -894,7 +913,13 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
        }
 
        bool assigned_any = false;
-       struct list_head assign_later = LIST_HEAD_INIT(assign_later);
+       struct {
+               struct avl_node node;
+       } *entry, *n_entry;
+       struct avl_tree assign_later;
+
+       avl_init(&assign_later, prefix_assignment_cmp, false, NULL);
+
        vlist_for_each_element(&interfaces, iface, node) {
                if (iface->assignment_length < 48 ||
                                iface->assignment_length > 64)
@@ -923,6 +948,7 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
 
                c->length = iface->assignment_length;
                c->assigned = iface->assignment_hint;
+               c->weight = iface->assignment_weight;
                c->addr = in6addr_any;
                c->enabled = false;
                memcpy(c->name, iface->name, namelen);
@@ -935,27 +961,25 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
                                                "of size %hhu for %s, trying other\n", c->length, c->name);
                        }
 
-                       struct list_head *next = &assign_later;
-                       struct device_prefix_assignment *n;
-                       list_for_each_entry(n, &assign_later, head) {
-                               if (n->length < c->length) {
-                                       next = &n->head;
-                                       break;
-                               }
-                       }
-                       list_add_tail(&c->head, next);
+                       entry = calloc(1, sizeof(*entry));
+                       if (!entry)
+                               continue;
+
+                       entry->node.key = c;
+                       avl_insert(&assign_later, &entry->node);
                }
 
                if (c->assigned != -1)
                        assigned_any = true;
        }
 
-       // Then try to assign all other + failed custom assignments
-       while (!list_empty(&assign_later)) {
-               c = list_first_entry(&assign_later, struct device_prefix_assignment, head);
-               list_del(&c->head);
-
+       /* Then try to assign all other + failed custom assignments */
+       avl_for_each_element_safe(&assign_later, entry, node, n_entry) {
                bool assigned = false;
+
+               c = (struct device_prefix_assignment *)entry->node.key;
+               avl_delete(&assign_later, &entry->node);
+
                do {
                        assigned = interface_prefix_assign(&prefix->assignments, c);
                } while (!assigned && ++c->length <= 64);
@@ -964,9 +988,10 @@ static void interface_update_prefix_assignments(struct device_prefix *prefix, bo
                        netifd_log_message(L_WARNING, "Failed to assign subprefix "
                                        "of size %hhu for %s\n", c->length, c->name);
                        free(c);
-               } else {
+               } else
                        assigned_any = true;
-               }
+
+               free(entry);
        }
 
        list_for_each_entry(c, &prefix->assignments, head)

diff --git a/interface-ip.h b/interface-ip.h
index 01727c9b8ae063b31e2d0634e3d815e1346d450a..197bd9a5a1c7e3304c7f3e3efc5a4128f00f425b 100644 (file)
--- a/interface-ip.h
+++ b/interface-ip.h
@@ -59,6 +59,7 @@ struct device_prefix_assignment {
        struct list_head head;
        int32_t assigned;
        uint8_t length;
+       int weight;
        struct in6_addr addr;
        bool enabled;
        char name[];

diff --git a/interface.c b/interface.c
index 522e7fe0c40c888351857e7e6874ea7f8f2d8739..f150f7d877ca210667f27f56eb6127b9f62fc805 100644 (file)
--- a/interface.c
+++ b/interface.c
@@ -46,6 +46,7 @@ enum {
        IFACE_ATTR_DELEGATE,
        IFACE_ATTR_IP6IFACEID,
        IFACE_ATTR_FORCE_LINK,
+       IFACE_ATTR_IP6WEIGHT,
        IFACE_ATTR_MAX
 };
 
@@ -68,6 +69,7 @@ static const struct blobmsg_policy iface_attrs[IFACE_ATTR_MAX] = {
        [IFACE_ATTR_DELEGATE] = { .name = "delegate", .type = BLOBMSG_TYPE_BOOL },
        [IFACE_ATTR_IP6IFACEID] = { .name = "ip6ifaceid", .type = BLOBMSG_TYPE_STRING },
        [IFACE_ATTR_FORCE_LINK] = { .name = "force_link", .type = BLOBMSG_TYPE_BOOL },
+       [IFACE_ATTR_IP6WEIGHT] = { .name = "ip6weight", .type = BLOBMSG_TYPE_INT32 },
 };
 
 const struct uci_blob_param_list interface_attr_list = {
@@ -497,6 +499,7 @@ interface_merge_assignment_data(struct interface *old, struct interface *new)
        bool changed = (old->assignment_hint != new->assignment_hint ||
                        old->assignment_length != new->assignment_length ||
                        old->assignment_iface_id_selection != new->assignment_iface_id_selection ||
+                       old->assignment_weight != new->assignment_weight ||
                        (old->assignment_iface_id_selection == IFID_FIXED &&
                         memcmp(&old->assignment_fixed_iface_id, &new->assignment_fixed_iface_id,
                                sizeof(old->assignment_fixed_iface_id))) ||
@@ -534,6 +537,7 @@ interface_merge_assignment_data(struct interface *old, struct interface *new)
                old->assignment_length = new->assignment_length;
                old->assignment_iface_id_selection = new->assignment_iface_id_selection;
                old->assignment_fixed_iface_id = new->assignment_fixed_iface_id;
+               old->assignment_weight = new->assignment_weight;
                interface_refresh_assignments(true);
        }
 }
@@ -842,6 +846,8 @@ interface_alloc(const char *name, struct blob_attr *config)
        if ((cur = tb[IFACE_ATTR_IP6CLASS]))
                interface_add_assignment_classes(iface, cur);
 
+       if ((cur = tb[IFACE_ATTR_IP6WEIGHT]))
+               iface->assignment_weight = blobmsg_get_u32(cur);
 
        if ((cur = tb[IFACE_ATTR_IP4TABLE])) {
                if (!system_resolve_rt_table(blobmsg_data(cur), &iface->ip4table))

diff --git a/interface.h b/interface.h
index 7d5b3094346a9ac1f388caea76bbc740e300e09b..147232436a8ead3aeecbda3ab87b1fb20bc42d4a 100644 (file)
--- a/interface.h
+++ b/interface.h
@@ -155,6 +155,7 @@ struct interface {
        uint8_t assignment_length;
        int32_t assignment_hint;
        struct list_head assignment_classes;
+       int assignment_weight;
 
        /* errors/warnings while trying to bring up the interface */
        struct list_head errors;

diff --git a/ubus.c b/ubus.c
index 66f714a5f0ca1976e4b47db024e411d20f916bec..1b1a4cd0c9a048ff313b81e6a7aa4527d77bf70f 100644 (file)
--- a/ubus.c
+++ b/ubus.c
@@ -698,6 +698,8 @@ netifd_dump_status(struct interface *iface)
                blobmsg_add_u32(&b, "metric", iface->metric);
                blobmsg_add_u32(&b, "dns_metric", iface->dns_metric);
                blobmsg_add_u8(&b, "delegation", !iface->proto_ip.no_delegation);
+               if (iface->assignment_weight)
+                       blobmsg_add_u32(&b, "ip6weight", iface->assignment_weight);
                a = blobmsg_open_array(&b, "ipv4-address");
                interface_ip_dump_address_list(&iface->config_ip, false, true);
                interface_ip_dump_address_list(&iface->proto_ip, false, true);