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resolved: when picking a new hostname make sure two hosts pick different ones

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This way we can avoid always picking the same replacement hostnames when
picking one.
This commit is contained in:
Lennart Poettering 2014-08-10 23:10:08 +02:00
parent 4d91eec42d
commit 556a22945f
1 changed files with 10 additions and 2 deletions
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12
src/resolve/resolved-manager.c
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@ -1646,7 +1646,7 @@ void manager_refresh_rrs(Manager *m) {
int manager_next_hostname(Manager *m) {
const char *p;
uint64_t u;
uint64_t u, a;
char *h;
assert(m);
@ -1664,7 +1664,15 @@ int manager_next_hostname(Manager *m) {
if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
u = 1;
u++;
/* Add a random number to the old value. This way we can avoid
* that two hosts pick the same hostname, win on IPv4 and lose
* on IPv6 (or vice versa), and pick the same hostname
* replacement hostname, ad infinitum. We still want the
* numbers to go up monotonically, hence we just add a random
* value 1..10 */
random_bytes(&a, sizeof(a));
u += 1 + a % 10;
if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->hostname), m->hostname, u) < 0)
return -ENOMEM;