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authorLennart Poettering <lennart@poettering.net>2014-12-03 21:42:58 +0100
committerLennart Poettering <lennart@poettering.net>2014-12-03 21:48:45 +0100
commite9140aff750e4f251f5f09b67412fed995fe9c47 (patch)
tree30f2c292e0154cfee8ce91bdf2c47674030255e9 /src/nss-myhostname
parent144232a8e0ea77eed8c5a456832758681b5b3511 (diff)
nss-myhostname: always resolve the host name "gateway" to the local default gateway
This is useful inside of containers or local networks to intrdouce a stable name of the default gateway host (in case of containers usually the host, in case of LANs usually local router).
Diffstat (limited to 'src/nss-myhostname')
-rw-r--r--src/nss-myhostname/nss-myhostname.c78
1 files changed, 59 insertions, 19 deletions
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 86e7be2aa1..4a5bf759a9 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -77,6 +77,18 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
canonical = "localhost";
local_address_ipv4 = htonl(INADDR_LOOPBACK);
+
+ } else if (streq(name, "gateway")) {
+
+ n_addresses = local_gateways(NULL, 0, &addresses);
+ if (n_addresses <= 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ canonical = "gateway";
+
} else {
hn = gethostname_malloc();
if (!hn) {
@@ -314,7 +326,7 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
_cleanup_free_ struct local_address *addresses = NULL;
const char *canonical, *additional = NULL;
_cleanup_free_ char *hn = NULL;
- uint32_t local_address_ipv4;
+ uint32_t local_address_ipv4 = 0;
int n_addresses = 0;
assert(name);
@@ -335,6 +347,18 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
if (is_localhost(name)) {
canonical = "localhost";
local_address_ipv4 = htonl(INADDR_LOOPBACK);
+
+ } else if (streq(name, "gateway")) {
+
+ n_addresses = local_gateways(NULL, af, &addresses);
+ if (n_addresses <= 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ canonical = "gateway";
+
} else {
hn = gethostname_malloc();
if (!hn) {
@@ -349,7 +373,7 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
return NSS_STATUS_NOTFOUND;
}
- n_addresses = local_addresses(NULL, 0, &addresses);
+ n_addresses = local_addresses(NULL, af, &addresses);
if (n_addresses < 0)
n_addresses = 0;
@@ -426,15 +450,41 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
}
n_addresses = local_addresses(NULL, 0, &addresses);
- if (n_addresses < 0)
- n_addresses = 0;
+ if (n_addresses > 0) {
+ for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
+ if (af != a->family)
+ continue;
- for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
- if (af != a->family)
- continue;
+ if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
- if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
- goto found;
+ hn = gethostname_malloc();
+ if (!hn) {
+ *errnop = ENOMEM;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ canonical = hn;
+ goto found;
+ }
+ }
+ }
+
+ free(addresses);
+ addresses = NULL;
+
+ n_addresses = local_gateways(NULL, 0, &addresses);
+ if (n_addresses > 0) {
+ for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
+ if (af != a->family)
+ continue;
+
+ if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
+
+ canonical = "gateway";
+ goto found;
+ }
+ }
}
*errnop = ENOENT;
@@ -443,16 +493,6 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
return NSS_STATUS_NOTFOUND;
found:
- if (!canonical) {
- hn = gethostname_malloc();
- if (!hn) {
- *errnop = ENOMEM;
- *h_errnop = NO_RECOVERY;
- return NSS_STATUS_TRYAGAIN;
- }
-
- canonical = hn;
- }
return fill_in_hostent(
canonical, additional,