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authorLennart Poettering <lennart@poettering.net>2016-02-13 20:26:30 +0100
committerLennart Poettering <lennart@poettering.net>2016-02-13 20:33:49 +0100
commitc3be369faa5f73c3b97c0088876bafdbfef43dae (patch)
tree20de1d39881f77e3099a4c78ae310bd7360f2448 /src
parentee116b54a3d0feb3f724f87ccf3f4cbb647d7e73 (diff)
resolved: extend ResolveHostname() bus call so that it can parse IP addresses
If the hostname passed to ResolveHostname() is actually an IP address that is correctly formatted as string parse it as such, avoid any DNS traffic and return the data in parsed form. This is useful for clients which can simply call the bus function now without caring about the precise formatting of specified hostnames. This mimics getaddrinfo()'s behaviour with the AI_NUMERICHOST flag set. Note that this logic is only implemented for ResolveHostname(), but not for calls such as ResolveRecord(), for which only DNS domain names may be used as input. The "authenticated" flag is set for look-ups of this type, after all no untrusted network traffic is involved.
Diffstat (limited to 'src')
-rw-r--r--src/resolve/resolved-bus.c72
1 files changed, 68 insertions, 4 deletions
diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c
index 00076fdf1a..6f08c43327 100644
--- a/src/resolve/resolved-bus.c
+++ b/src/resolve/resolved-bus.c
@@ -23,6 +23,7 @@
#include "dns-domain.h"
#include "resolved-bus.h"
#include "resolved-def.h"
+#include "resolved-dns-synthesize.h"
#include "resolved-link-bus.h"
static int reply_query_state(DnsQuery *q) {
@@ -233,6 +234,65 @@ static int check_ifindex_flags(int ifindex, uint64_t *flags, uint64_t ok, sd_bus
return 0;
}
+static int parse_as_address(sd_bus_message *m, int ifindex, const char *hostname, int family, uint64_t flags) {
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ _cleanup_free_ char *canonical = NULL;
+ union in_addr_union parsed;
+ int r, ff;
+
+ /* Check if the hostname is actually already an IP address formatted as string. In that case just parse it,
+ * let's not attempt to look it up. */
+
+ r = in_addr_from_string_auto(hostname, &ff, &parsed);
+ if (r < 0) /* not an address */
+ return 0;
+
+ if (family != AF_UNSPEC && ff != family)
+ return sd_bus_reply_method_errorf(m, BUS_ERROR_NO_SUCH_RR, "The specified address is not of the requested family.");
+
+ r = sd_bus_message_new_method_return(m, &reply);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_open_container(reply, 'a', "(iiay)");
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_open_container(reply, 'r', "iiay");
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(reply, "ii", ifindex, ff);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append_array(reply, 'y', &parsed, FAMILY_ADDRESS_SIZE(ff));
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_close_container(reply);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_close_container(reply);
+ if (r < 0)
+ return r;
+
+ /* When an IP address is specified we just return it as canonical name, in order to avoid a DNS
+ * look-up. However, we reformat it to make sure it's in a truly canonical form (i.e. on IPv6 the inner
+ * omissions are always done the same way). */
+ r = in_addr_to_string(ff, &parsed, &canonical);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_message_append(reply, "st", canonical,
+ SD_RESOLVED_FLAGS_MAKE(dns_synthesize_protocol(flags), ff, true));
+ if (r < 0)
+ return r;
+
+ return sd_bus_send(sd_bus_message_get_bus(m), reply, NULL);
+}
+
static int bus_method_resolve_hostname(sd_bus_message *message, void *userdata, sd_bus_error *error) {
_cleanup_(dns_question_unrefp) DnsQuestion *question_idna = NULL, *question_utf8 = NULL;
Manager *m = userdata;
@@ -254,15 +314,19 @@ static int bus_method_resolve_hostname(sd_bus_message *message, void *userdata,
if (!IN_SET(family, AF_INET, AF_INET6, AF_UNSPEC))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family);
- r = dns_name_is_valid(hostname);
+ r = check_ifindex_flags(ifindex, &flags, SD_RESOLVED_NO_SEARCH, error);
if (r < 0)
return r;
- if (r == 0)
- return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", hostname);
- r = check_ifindex_flags(ifindex, &flags, SD_RESOLVED_NO_SEARCH, error);
+ r = parse_as_address(message, ifindex, hostname, family, flags);
+ if (r != 0)
+ return r;
+
+ r = dns_name_is_valid(hostname);
if (r < 0)
return r;
+ if (r == 0)
+ return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", hostname);
r = dns_question_new_address(&question_utf8, family, hostname, false);
if (r < 0)