modules/hints: allow overriding the TTL

Fixes #442.

diff --git a/modules/hints/README.rst b/modules/hints/README.rst
index a42d19ca04496af4a539862719effa1596e49b29..3630268a4771122f38fc65b685cbca765fc25d18 100644 (file)
--- a/modules/hints/README.rst
+++ b/modules/hints/README.rst
@@ -111,3 +111,11 @@ Properties
 
   If set to true (the default), NODATA will be synthesised for matching hint name, but mismatching type (e.g. AAAA query when only A hint exists).
 
+.. function:: hints.ttl([new_ttl])
+
+  :param int new_ttl: new TTL to set (optional)
+  :return: the TTL setting
+
+  This function allows to read and write the TTL value used for records generated by the hints module.
+  The default is zero.
+

diff --git a/modules/hints/hints.c b/modules/hints/hints.c
index 84e2e990196ee4759a82f71b160b43acad405b07..a2c90d0a1d0475779df00fdc09a58decfd75752e 100644 (file)
--- a/modules/hints/hints.c
+++ b/modules/hints/hints.c
@@ -33,6 +33,9 @@
 #include "lib/module.h"
 #include "lib/layer.h"
 
+#include <inttypes.h>
+#include <math.h>
+
 /* Defaults */
 #define VERBOSE_MSG(qry, ...) QRVERBOSE(qry, "hint",  __VA_ARGS__)
 #define ERR_MSG(...) kr_log_error("[     ][hint] " __VA_ARGS__)
@@ -41,6 +44,7 @@ struct hints_data {
        struct kr_zonecut hints;
        struct kr_zonecut reverse_hints;
        bool use_nodata; /**< See hint_use_nodata() description, exposed via lua. */
+       uint32_t ttl;    /**< TTL used for the hints, exposed via lua. */
 };
 
 /** Useful for returning from module properties. */
@@ -79,16 +83,17 @@ static int put_answer(knot_pkt_t *pkt, struct kr_query *qry, knot_rrset_t *rr, b
        return ret;
 }
 
-static int satisfy_reverse(struct kr_zonecut *hints, knot_pkt_t *pkt, struct kr_query *qry, bool use_nodata)
+static int satisfy_reverse(/*const*/ struct hints_data *data,
+                          knot_pkt_t *pkt, struct kr_query *qry)
 {
        /* Find a matching name */
-       pack_t *addr_set = kr_zonecut_find(hints, qry->sname);
+       pack_t *addr_set = kr_zonecut_find(&data->reverse_hints, qry->sname);
        if (!addr_set || addr_set->len == 0) {
                return kr_error(ENOENT);
        }
        knot_dname_t *qname = knot_dname_copy(qry->sname, &pkt->mm);
        knot_rrset_t rr;
-       knot_rrset_init(&rr, qname, KNOT_RRTYPE_PTR, KNOT_CLASS_IN, 0);
+       knot_rrset_init(&rr, qname, KNOT_RRTYPE_PTR, KNOT_CLASS_IN, data->ttl);
 
        /* Append address records from hints */
        uint8_t *addr = pack_last(*addr_set);
@@ -98,19 +103,20 @@ static int satisfy_reverse(struct kr_zonecut *hints, knot_pkt_t *pkt, struct kr_
                knot_rrset_add_rdata(&rr, addr_val, len, &pkt->mm);
        }
 
-       return put_answer(pkt, qry, &rr, use_nodata);
+       return put_answer(pkt, qry, &rr, data->use_nodata);
 }
 
-static int satisfy_forward(struct kr_zonecut *hints, knot_pkt_t *pkt, struct kr_query *qry, bool use_nodata)
+static int satisfy_forward(/*const*/ struct hints_data *data,
+                          knot_pkt_t *pkt, struct kr_query *qry)
 {
        /* Find a matching name */
-       pack_t *addr_set = kr_zonecut_find(hints, qry->sname);
+       pack_t *addr_set = kr_zonecut_find(&data->hints, qry->sname);
        if (!addr_set || addr_set->len == 0) {
                return kr_error(ENOENT);
        }
        knot_dname_t *qname = knot_dname_copy(qry->sname, &pkt->mm);
        knot_rrset_t rr;
-       knot_rrset_init(&rr, qname, qry->stype, qry->sclass, 0);
+       knot_rrset_init(&rr, qname, qry->stype, qry->sclass, data->ttl);
        size_t family_len = sizeof(struct in_addr);
        if (rr.type == KNOT_RRTYPE_AAAA) {
                family_len = sizeof(struct in6_addr);
@@ -127,7 +133,7 @@ static int satisfy_forward(struct kr_zonecut *hints, knot_pkt_t *pkt, struct kr_
                addr = pack_obj_next(addr);
        }
 
-       return put_answer(pkt, qry, &rr, use_nodata);
+       return put_answer(pkt, qry, &rr, data->use_nodata);
 }
 
 static int query(kr_layer_t *ctx, knot_pkt_t *pkt)
@@ -147,11 +153,11 @@ static int query(kr_layer_t *ctx, knot_pkt_t *pkt)
        switch(qry->stype) {
        case KNOT_RRTYPE_A:
        case KNOT_RRTYPE_AAAA: /* Find forward record hints */
-               if (satisfy_forward(&data->hints, pkt, qry, data->use_nodata) != 0)
+               if (satisfy_forward(data, pkt, qry) != 0)
                        return ctx->state;
                break;
        case KNOT_RRTYPE_PTR: /* Find PTR record */
-               if (satisfy_reverse(&data->reverse_hints, pkt, qry, data->use_nodata) != 0)
+               if (satisfy_reverse(data, pkt, qry) != 0)
                        return ctx->state;
                break;
        default:
@@ -570,6 +576,29 @@ static char* hint_use_nodata(void *env, struct kr_module *module, const char *ar
        return bool2jsonstr(true);
 }
 
+static char* hint_ttl(void *env, struct kr_module *module, const char *args)
+{
+       struct hints_data *data = module->data;
+
+       /* Do no change on nonsense TTL values (incl. suspicious floats). */
+       JsonNode *root_node = args ? json_decode(args) : NULL;
+       if (root_node && root_node->tag == JSON_NUMBER) {
+               double ttl_d = root_node->number_;
+               uint32_t ttl = round(ttl_d);
+               if (ttl_d >= 0 && fabs(ttl_d - ttl) * 64 < 1) {
+                       data->ttl = ttl;
+               }
+       }
+       json_delete(root_node);
+
+       /* Always return the current TTL setting.  Plain number is valid JSON. */
+       char *result = NULL;
+       if (-1 == asprintf(&result, "%"PRIu32, data->ttl)) {
+               result = NULL;
+       }
+       return result;
+}
+
 /*
  * Module implementation.
  */
@@ -609,6 +638,7 @@ int hints_init(struct kr_module *module)
        kr_zonecut_init(&data->hints, (const uint8_t *)(""), pool);
        kr_zonecut_init(&data->reverse_hints, (const uint8_t *)(""), pool);
        data->use_nodata = true;
+       data->ttl = 0;
        module->data = data;
 
        return kr_ok();
@@ -654,6 +684,7 @@ struct kr_prop *hints_props(void)
            { &hint_set,    "set", "Set {name, address} hint.", },
            { &hint_del,    "del", "Delete one {name, address} hint or all addresses for the name.", },
            { &hint_get,    "get", "Retrieve hint for given name.", },
+           { &hint_ttl,    "ttl", "Set/get TTL used for the hints.", },
            { &hint_add_hosts, "add_hosts", "Load a file with hosts-like formatting and add contents into hints.", },
            { &hint_root,   "root", "Replace root hints set (empty value to return current list).", },
            { &hint_root_file, "root_file", "Replace root hints set from a zonefile.", },