Add new info functions to resolver for use by Netd.
android_net_res_stats_get_info_for_net returns the current name servers, search
domains, parameters and stats for the given network ID.
android_net_res_stats_aggregate provides statistics such as errors counts from
the raw stats data reported by android_net_res_stats_get_info_for_net.
android_net_res_stats_get_usable_servers uses the data returned by
android_net_res_stats_aggregate to determine which of the servers are
considered valid or broken by the resolver.
BUG: 25731675
Change-Id: I6059b68e5e8b809027a4d3135f6081588bee8a7d
diff --git a/libc/dns/resolv/res_cache.c b/libc/dns/resolv/res_cache.c
index 5f51c49..02887f2 100644
--- a/libc/dns/resolv/res_cache.c
+++ b/libc/dns/resolv/res_cache.c
@@ -27,6 +27,7 @@
*/
#include "resolv_cache.h"
+
#include <resolv.h>
#include <stdarg.h>
#include <stdio.h>
@@ -1238,8 +1239,7 @@
int revision_id; // # times the nameservers have been replaced
struct __res_params params;
struct __res_stats nsstats[MAXNS];
- // TODO: replace with char* defdname[MAXDNSRCH]
- char defdname[256];
+ char defdname[MAXDNSRCHPATH];
int dnsrch_offset[MAXDNSRCH+1]; // offsets into defdname
};
@@ -2183,6 +2183,68 @@
}
int
+android_net_res_stats_get_info_for_net(unsigned netid, int* nscount,
+ struct sockaddr_storage servers[MAXNS], int* dcount, char domains[MAXDNSRCH][MAXDNSRCHPATH],
+ struct __res_params* params, struct __res_stats stats[MAXNS]) {
+ int revision_id = -1;
+ pthread_mutex_lock(&_res_cache_list_lock);
+
+ struct resolv_cache_info* info = _find_cache_info_locked(netid);
+ if (info) {
+ if (info->nscount > MAXNS) {
+ pthread_mutex_unlock(&_res_cache_list_lock);
+ XLOG("%s: nscount %d > MAXNS %d", __FUNCTION__, info->nscount, MAXNS);
+ errno = EFAULT;
+ return -1;
+ }
+ int i;
+ for (i = 0; i < info->nscount; i++) {
+ // Verify that the following assumptions are held, failure indicates corruption:
+ // - getaddrinfo() may never return a sockaddr > sockaddr_storage
+ // - all addresses are valid
+ // - there is only one address per addrinfo thanks to numeric resolution
+ int addrlen = info->nsaddrinfo[i]->ai_addrlen;
+ if (addrlen < (int) sizeof(struct sockaddr) ||
+ addrlen > (int) sizeof(servers[0])) {
+ pthread_mutex_unlock(&_res_cache_list_lock);
+ XLOG("%s: nsaddrinfo[%d].ai_addrlen == %d", __FUNCTION__, i, addrlen);
+ errno = EMSGSIZE;
+ return -1;
+ }
+ if (info->nsaddrinfo[i]->ai_addr == NULL) {
+ pthread_mutex_unlock(&_res_cache_list_lock);
+ XLOG("%s: nsaddrinfo[%d].ai_addr == NULL", __FUNCTION__, i);
+ errno = ENOENT;
+ return -1;
+ }
+ if (info->nsaddrinfo[i]->ai_next != NULL) {
+ pthread_mutex_unlock(&_res_cache_list_lock);
+ XLOG("%s: nsaddrinfo[%d].ai_next != NULL", __FUNCTION__, i);
+ errno = ENOTUNIQ;
+ return -1;
+ }
+ }
+ *nscount = info->nscount;
+ for (i = 0; i < info->nscount; i++) {
+ memcpy(&servers[i], info->nsaddrinfo[i]->ai_addr, info->nsaddrinfo[i]->ai_addrlen);
+ stats[i] = info->nsstats[i];
+ }
+ for (i = 0; i < MAXDNSRCH; i++) {
+ if (info->dnsrch_offset[i] == -1) {
+ break;
+ }
+ strlcpy(domains[i], info->defdname + info->dnsrch_offset[i], MAXDNSRCHPATH);
+ }
+ *dcount = i;
+ *params = info->params;
+ revision_id = info->revision_id;
+ }
+
+ pthread_mutex_unlock(&_res_cache_list_lock);
+ return revision_id;
+}
+
+int
_resolv_cache_get_resolver_stats( unsigned netid, struct __res_params* params,
struct __res_stats stats[MAXNS]) {
int revision_id = -1;