context: root hints, slist bugfixes and sorting

diff --git a/lib/context.c b/lib/context.c
index b6b4293253369aa49ae8d8661a07dffac9523c71..8f64da2f23fe19e816fb79907fa008afc60b9c50 100644 (file)
--- a/lib/context.c
+++ b/lib/context.c
@@ -4,9 +4,53 @@
 #include <common/sockaddr.h>
 #include "context.h"
 
+/* \brief Root hint descriptor. */
+struct hint_info {
+       const char *name;
+       const char *addr;
+       const char *zone;
+};
+
+/* Initialize with SBELT name servers. */
+#define HINT_COUNT 13
+static const struct hint_info SBELT[HINT_COUNT] = {
+        { "a.root-servers.net.", "198.41.0.4", "." },
+        { "b.root-servers.net.", "192.228.79.201", "." },
+        { "c.root-servers.net.", "192.33.4.12", "." },
+        { "d.root-servers.net.", "199.7.91.13", "." },
+        { "e.root-servers.net.", "192.203.230.10", "." },
+        { "f.root-servers.net.", "192.5.5.241", "." },
+        { "g.root-servers.net.", "192.112.36.4", "." },
+        { "h.root-servers.net.", "128.63.2.53", "." },
+        { "i.root-servers.net.", "192.36.148.17", "." },
+        { "j.root-servers.net.", "192.58.128.30", "." },
+        { "k.root-servers.net.", "193.0.14.129", "." },
+        { "l.root-servers.net.", "199.7.83.42", "." },
+        { "m.root-servers.net.", "202.12.27.33", "." }
+};
+
+/* TODO: debug, remove */
+#ifndef NDEBUG
+static void print_slist(struct kr_context *ctx)
+{
+       char *sname = knot_dname_to_str(ctx->sname);
+       printf("SLIST(%s): \n", sname);
+       free(sname);
+       struct kr_ns *ns = NULL;
+       WALK_LIST(ns, ctx->slist) {
+               char *strname = knot_dname_to_str(ns->name);
+               char addr_str[SOCKADDR_STRLEN];
+               sockaddr_tostr(&ns->addr, addr_str, sizeof(addr_str));
+               printf("[%d] %s:%s ", ns->closeness, strname, addr_str);
+               free(strname);
+       }
+       printf("\n");
+}
+#endif
+
 /*! \brief Initialize NS descriptor. */
 static struct kr_ns *init_ns(mm_ctx_t *mm, const knot_dname_t *name,
-                             const struct sockaddr *addr, unsigned closeness)
+                             const struct sockaddr *addr)
 {
        struct kr_ns *ns = mm_alloc(mm, sizeof(struct kr_ns));
        if (ns == NULL) {
@@ -21,22 +65,48 @@ static struct kr_ns *init_ns(mm_ctx_t *mm, const knot_dname_t *name,
        }
 
        memcpy(&ns->addr, addr, sockaddr_len(addr));
-       ns->closeness = closeness;
 
        return ns;
 }
 
-/*! \brief Insert NS before an item. */
-static void insert_ns(struct kr_ns *cur, struct kr_ns *inserted)
+/*! \brief Insert before an item. */
+static void insert_before(struct kr_ns *cur, struct kr_ns *inserted)
 {
        insert_node((node_t *)inserted, (node_t *)cur);
        rem_node((node_t *)cur);
        insert_node((node_t *)cur, (node_t *)inserted);
 }
 
+/*! \brief Calculate closeness (# of common labels with sname). */
+static unsigned closeness_score(const knot_dname_t *sname, const knot_dname_t *zone)
+{
+       /* Longer or non-equal names of the same length can't contain delegations. */
+       if (sname && (knot_dname_is_sub(sname, zone) || knot_dname_is_equal(zone, sname))) {
+               return KNOT_DNAME_MAXLABELS - knot_dname_matched_labels(zone, sname);
+       }
+
+       return KNOT_DNAME_MAXLABELS + 1; /* N/A */
+}
+
+/* \brief (Re)insert name server to SLIST. */
+static void insert_ns(struct kr_context *ctx, struct kr_ns *ns)
+{
+       struct kr_ns *it = NULL;
+       WALK_LIST(it, ctx->slist) {
+               if (it->closeness > ns->closeness) {
+                       insert_before(it, ns);
+                       return;
+               }
+       }
+
+       /* No closer match found. */
+       add_tail(&ctx->slist, (node_t *)ns);
+}
+
 /*! \brief Remove NS descriptor. */
 static void remove_ns(mm_ctx_t *mm, struct kr_ns *ns)
 {
+       rem_node((node_t *)ns);
        mm_free(mm, ns->name);
        mm_free(mm, ns);
 }
@@ -45,13 +115,23 @@ int kr_context_init(struct kr_context *ctx, mm_ctx_t *mm)
 {
        memset(ctx, 0, sizeof(struct kr_context));
 
-       ctx->mm = mm;
+       ctx->pool = mm;
        init_list(&ctx->slist);
+       kr_context_reset(ctx);
 
        return 0;
 }
 
-int kr_context_close(struct kr_context *ctx)
+int kr_context_reset(struct kr_context *ctx)
+{
+       while(kr_slist_pop(ctx) == 0);
+
+       kr_slist_init(ctx);
+
+       return 0;
+}
+
+int kr_context_deinit(struct kr_context *ctx)
 {
        /* TODO: free slist, pending queries. */
        return -1;
@@ -61,7 +141,7 @@ int kr_result_init(struct kr_context *ctx, struct kr_result *result)
 {
        memset(result, 0, sizeof(struct kr_result));
 
-       knot_pkt_t *ans = knot_pkt_new(NULL, KNOT_WIRE_MAX_PKTSIZE, ctx->mm);
+       knot_pkt_t *ans = knot_pkt_new(NULL, KNOT_WIRE_MAX_PKTSIZE, ctx->pool);
        if (ans == NULL) {
                return -1;
        }
@@ -71,39 +151,41 @@ int kr_result_init(struct kr_context *ctx, struct kr_result *result)
        knot_wire_set_qr(ans->wire);
 
        result->ans = ans;
-       result->cname = ctx->sname;
        gettimeofday(&result->t_start, NULL);
 
        return 0;
 }
 
-int kr_result_clear(struct kr_result *result)
+int kr_result_deinit(struct kr_result *result)
 {
        knot_pkt_free(&result->ans);
 
        return 0;
 }
 
-int kr_slist_add(struct kr_context *ctx, const knot_dname_t *name, const struct sockaddr *addr)
+int kr_slist_init(struct kr_context *ctx)
 {
-       /* Closeness is represented by a number of common labels. */
-       int closeness = knot_dname_matched_labels(name, ctx->sname);
+       int ret = 0;
+       struct sockaddr_storage ss;
+       for (unsigned i = 0; i < HINT_COUNT; ++i) {
+               ret = sockaddr_set(&ss, AF_INET, SBELT[i].addr, 53);
+               assert(ret == 0);
+               kr_slist_add(ctx, knot_dname_from_str(SBELT[i].zone),
+                            (struct sockaddr *)&ss);
+       }
+
+       return 0;
+}
 
-       struct kr_ns *ns = init_ns(ctx->mm, name, addr, closeness);
+int kr_slist_add(struct kr_context *ctx, const knot_dname_t *name, const struct sockaddr *addr)
+{
+       struct kr_ns *ns = init_ns(ctx->pool, name, addr);
        if (ns == NULL) {
                return -1;
        }
 
-       struct kr_ns *iter = NULL;
-       WALK_LIST(iter, ctx->slist) {
-               if (iter->closeness < closeness) {
-                       insert_ns(iter, ns);
-                       return 0;
-               }
-       }
+       insert_ns(ctx, ns);
 
-       /* No closer match found. */
-       add_tail(&ctx->slist, (node_t *)ns);
        return 0;
 }
 
@@ -116,14 +198,29 @@ struct kr_ns *kr_slist_top(struct kr_context *ctx)
        return (struct kr_ns *)HEAD(ctx->slist);
 }
 
+int kr_slist_sort(struct kr_context *ctx)
+{
+       list_t copy = ctx->slist;
+       init_list(&ctx->slist);
+
+       /* Recalculate closeness and reinsert. */
+       struct kr_ns *it = NULL, *next = NULL;
+       WALK_LIST_DELSAFE(it, next, copy) {
+               it->closeness = closeness_score(ctx->sname, it->name);
+               insert_ns(ctx, it);
+       }
+
+       return 0;
+}
+
 int kr_slist_pop(struct kr_context *ctx)
 {
        struct kr_ns *top = kr_slist_top(ctx);
-       if (top) {
+       if (top == NULL) {
                return -1;
        }
 
-       rem_node((node_t *)top);
-       remove_ns(ctx->mm, top);
+       remove_ns(ctx->pool, top);
+
        return 0;
 }

diff --git a/lib/context.h b/lib/context.h
index 40571805a6ec01e5f3ddee5bb5bc197df9997580..7416dd9b3fffc756c35e098e49d3578021a249c1 100644 (file)
--- a/lib/context.h
+++ b/lib/context.h
@@ -49,17 +49,20 @@ struct kr_context
        uint16_t sclass;
        uint16_t next_id;
        list_t slist;
-       mm_ctx_t *mm;
+       mm_ctx_t *pool;
        unsigned state;
        unsigned options;
 };
 
 int kr_context_init(struct kr_context *ctx, mm_ctx_t *mm);
-int kr_context_close(struct kr_context *ctx);
+int kr_context_reset(struct kr_context *ctx);
+int kr_context_deinit(struct kr_context *ctx);
 
 int kr_result_init(struct kr_context *ctx, struct kr_result *result);
-int kr_result_clear(struct kr_result *result);
+int kr_result_deinit(struct kr_result *result);
 
+int kr_slist_init(struct kr_context *ctx);
 int kr_slist_add(struct kr_context *ctx, const knot_dname_t *name, const struct sockaddr *addr);
 struct kr_ns *kr_slist_top(struct kr_context *ctx);
+int kr_slist_sort(struct kr_context *ctx);
 int kr_slist_pop(struct kr_context *ctx);
\ No newline at end of file