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authorLennart Poettering <lennart@poettering.net>2015-12-03 17:27:13 +0100
committerLennart Poettering <lennart@poettering.net>2015-12-03 21:17:49 +0100
commit1b4f6e79ec51a57003896a0b605fba427b4a98d2 (patch)
tree88f95d5b8e9db07c62bfef5c8d789a1b6659d824 /src/resolve
parent2a44bec4f62833222a85ad8c90054468dfa75013 (diff)
resolved: optionally, allocate DnsResourceKey objects on the stack
Sometimes when looking up entries in hashmaps indexed by a DnsResourceKey it is helpful not having to allocate a full DnsResourceKey dynamically just to use it as search key. Instead, optionally allow allocation of a DnsResourceKey on the stack. Resource keys allocated like that of course are subject to other lifetime cycles than the usual Resource keys, hence initialize the reference counter to to (unsigned) -1. While we are at it, remove the prototype for dns_resource_key_new_dname() which was never implemented.
Diffstat (limited to 'src/resolve')
-rw-r--r--src/resolve/resolved-dns-cache.c19
-rw-r--r--src/resolve/resolved-dns-rr.c11
-rw-r--r--src/resolve/resolved-dns-rr.h15
-rw-r--r--src/resolve/resolved-dns-zone.c13
4 files changed, 28 insertions, 30 deletions
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 3f34017789..3abb0374b6 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -522,7 +522,6 @@ fail:
}
static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, DnsResourceKey *k) {
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *nsec_key = NULL, *cname_key = NULL;
DnsCacheItem *i;
const char *n;
int r;
@@ -540,35 +539,23 @@ static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, D
n = DNS_RESOURCE_KEY_NAME(k);
/* Check if we have an NSEC record instead for the name. */
- nsec_key = dns_resource_key_new(k->class, DNS_TYPE_NSEC, n);
- if (!nsec_key)
- return NULL;
-
- i = hashmap_get(c->by_key, nsec_key);
+ i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n));
if (i)
return i;
/* Check if we have a CNAME record instead */
- cname_key = dns_resource_key_new_cname(k);
- if (!cname_key)
- return NULL;
- i = hashmap_get(c->by_key, cname_key);
+ i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_CNAME, n));
if (i)
return i;
/* OK, let's look for cached DNAME records. */
for (;;) {
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dname_key = NULL;
char label[DNS_LABEL_MAX];
if (isempty(n))
return NULL;
- dname_key = dns_resource_key_new(k->class, DNS_TYPE_DNAME, n);
- if (!dname_key)
- return NULL;
-
- i = hashmap_get(c->by_key, dname_key);
+ i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_DNAME, n));
if (i)
return i;
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 281e228b12..b109934d3a 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -51,12 +51,6 @@ DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *
return k;
}
-DnsResourceKey* dns_resource_key_new_cname(const DnsResourceKey *key) {
- assert(key);
-
- return dns_resource_key_new(key->class, DNS_TYPE_CNAME, DNS_RESOURCE_KEY_NAME(key));
-}
-
DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname) {
int r;
@@ -137,6 +131,10 @@ DnsResourceKey* dns_resource_key_ref(DnsResourceKey *k) {
if (!k)
return NULL;
+ /* Static/const keys created with DNS_RESOURCE_KEY_CONST will
+ * set this to -1, they should not be reffed/unreffed */
+ assert(k->n_ref != (unsigned) -1);
+
assert(k->n_ref > 0);
k->n_ref++;
@@ -147,6 +145,7 @@ DnsResourceKey* dns_resource_key_unref(DnsResourceKey *k) {
if (!k)
return NULL;
+ assert(k->n_ref != (unsigned) -1);
assert(k->n_ref > 0);
if (k->n_ref == 1) {
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 2a103aab8d..adaca962fc 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -78,6 +78,19 @@ struct DnsResourceKey {
char *_name; /* don't access directy, use DNS_RESOURCE_KEY_NAME()! */
};
+/* Creates a temporary resource key. This is only useful to quickly
+ * look up something, without allocating a full DnsResourceKey object
+ * for it. Note that it is not OK to take references to this kind of
+ * resource key object. */
+#define DNS_RESOURCE_KEY_CONST(c, t, n) \
+ ((DnsResourceKey) { \
+ .n_ref = (unsigned) -1, \
+ .class = c, \
+ .type = t, \
+ ._name = (char*) n, \
+ })
+
+
struct DnsTxtItem {
size_t length;
LIST_FIELDS(DnsTxtItem, items);
@@ -221,8 +234,6 @@ static inline const char* DNS_RESOURCE_KEY_NAME(const DnsResourceKey *key) {
}
DnsResourceKey* dns_resource_key_new(uint16_t class, uint16_t type, const char *name);
-DnsResourceKey* dns_resource_key_new_cname(const DnsResourceKey *key);
-DnsResourceKey* dns_resource_key_new_dname(const DnsResourceKey *key);
DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const DnsResourceRecord *cname);
int dns_resource_key_new_append_suffix(DnsResourceKey **ret, DnsResourceKey *key, char *name);
DnsResourceKey* dns_resource_key_new_consume(uint16_t class, uint16_t type, char *name);
diff --git a/src/resolve/resolved-dns-zone.c b/src/resolve/resolved-dns-zone.c
index 493d11dd14..78f44d51a2 100644
--- a/src/resolve/resolved-dns-zone.c
+++ b/src/resolve/resolved-dns-zone.c
@@ -163,7 +163,6 @@ static int dns_zone_link_item(DnsZone *z, DnsZoneItem *i) {
}
static int dns_zone_item_probe_start(DnsZoneItem *i) {
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
DnsTransaction *t;
int r;
@@ -172,12 +171,14 @@ static int dns_zone_item_probe_start(DnsZoneItem *i) {
if (i->probe_transaction)
return 0;
- key = dns_resource_key_new(i->rr->key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(i->rr->key));
- if (!key)
- return -ENOMEM;
-
- t = dns_scope_find_transaction(i->scope, key, false);
+ t = dns_scope_find_transaction(i->scope, &DNS_RESOURCE_KEY_CONST(i->rr->key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(i->rr->key)), false);
if (!t) {
+ _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
+
+ key = dns_resource_key_new(i->rr->key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(i->rr->key));
+ if (!key)
+ return -ENOMEM;
+
r = dns_transaction_new(&t, i->scope, key);
if (r < 0)
return r;