picnoir/Systemd
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

resolved: filter out duplicate DNS servers when writing resolv.conf

Browse source
This commit is contained in:
Lennart Poettering 2014-08-12 12:21:10 +02:00
parent c2d6bd61ee
commit 87f5a19343
3 changed files with 67 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
src/resolve/resolved-dns-server.c
View file

@ -19,6 +19,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "siphash24.h"
#include "resolved-dns-server.h"
int dns_server_new(
@ -97,3 +99,24 @@ DnsServer* dns_server_free(DnsServer *s) {
return NULL;
}
unsigned long dns_server_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
const DnsServer *s = p;
uint64_t u;
siphash24((uint8_t*) &u, &s->address, FAMILY_ADDRESS_SIZE(s->family), hash_key);
u = u * hash_key[0] + u + s->family;
return u;
}
int dns_server_compare_func(const void *a, const void *b) {
const DnsServer *x = a, *y = b;
if (x->family < y->family)
return -1;
if (x->family > y->family)
return 1;
return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family));
}

3
src/resolve/resolved-dns-server.h
View file

@ -59,3 +59,6 @@ int dns_server_new(
const union in_addr_union *address);
DnsServer* dns_server_free(DnsServer *s);
unsigned long dns_server_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]);
int dns_server_compare_func(const void *a, const void *b);

51
src/resolve/resolved-manager.c
View file

@ -691,7 +691,7 @@ static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) {
}
if (*count == MAXNS)
fputs("# Too many DNS servers configured, the following entries may be ignored\n", f);
fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f);
fprintf(f, "nameserver %s\n", t);
(*count) ++;
@ -701,6 +701,7 @@ int manager_write_resolv_conf(Manager *m) {
static const char path[] = "/run/systemd/resolve/resolv.conf";
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
_cleanup_set_free_ Set *dns = NULL;
unsigned count = 0;
DnsServer *s;
Iterator i;
@ -712,6 +713,41 @@ int manager_write_resolv_conf(Manager *m) {
/* Read the system /etc/resolv.conf first */
manager_read_resolv_conf(m);
/* Add the full list to a set, to filter out duplicates */
dns = set_new(dns_server_hash_func, dns_server_compare_func);
if (!dns)
return -ENOMEM;
/* First add the system-wide servers */
LIST_FOREACH(servers, s, m->dns_servers) {
r = set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Then, add the per-link servers */
HASHMAP_FOREACH(l, m->links, i)
LIST_FOREACH(servers, s, l->dns_servers) {
r = set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* If we found nothing, add the fallback servers */
if (set_isempty(dns)) {
LIST_FOREACH(servers, s, m->fallback_dns_servers) {
r = set_put(dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
r = fopen_temporary(path, &f, &temp_path);
if (r < 0)
return r;
@ -724,15 +760,10 @@ int manager_write_resolv_conf(Manager *m) {
"# resolv.conf(5) in a different way, replace the symlink by a\n"
"# static file or a different symlink.\n\n", f);
LIST_FOREACH(servers, s, m->dns_servers)
write_resolve_conf_server(s, f, &count);
HASHMAP_FOREACH(l, m->links, i)
LIST_FOREACH(servers, s, l->dns_servers)
write_resolve_conf_server(s, f, &count);
if (count == 0) {
LIST_FOREACH(servers, s, m->fallback_dns_servers)
if (set_isempty(dns))
fputs("# No DNS servers known.\n", f);
else {
SET_FOREACH(s, dns, i)
write_resolve_conf_server(s, f, &count);
}