MEDIUM: dns: add a "resolve-net" option which allow to prefer an ip in a network
This options prioritize th choice of an ip address matching a network. This is
useful with clouds to prefer a local ip. In some cases, a cloud high
avalailibility service can be announced with many ip addresses on many
differents datacenters. The latency between datacenter is not negligible, so
this patch permitsto prefers a local datacenter. If none address matchs the
configured network, another address is selected.
diff --git a/include/types/dns.h b/include/types/dns.h
index cf784cd..757eaaf 100644
--- a/include/types/dns.h
+++ b/include/types/dns.h
@@ -55,6 +55,11 @@
#define DNS_FLAG_TRUNCATED 0x0200 /* mask for truncated flag */
#define DNS_FLAG_REPLYCODE 0x000F /* mask for reply code */
+/* max number of network preference entries are avalaible from the
+ * configuration file.
+ */
+#define SRV_MAX_PREF_NET 5
+
/* DNS request or response header structure */
struct dns_header {
unsigned short id:16; /* identifier */
@@ -142,6 +147,18 @@
struct dns_options {
int family_prio; /* which IP family should the resolver use when both are returned */
+ struct {
+ int family;
+ union {
+ struct in_addr in4;
+ struct in6_addr in6;
+ } addr;
+ union {
+ struct in_addr in4;
+ struct in6_addr in6;
+ } mask;
+ } pref_net[SRV_MAX_PREF_NET];
+ int pref_net_nb; /* The number of registered prefered networks. */
};
/*