Implement API to test for upstream DNS servers.

This commit is contained in:
Eugene Bujak 2018-09-19 19:12:09 +03:00
parent 0292d2b32b
commit e733c19504
2 changed files with 120 additions and 0 deletions

View File

@ -18,6 +18,7 @@ import (
"time"
"github.com/AdguardTeam/AdguardDNS/dnsfilter"
"github.com/miekg/dns"
"gopkg.in/asaskevich/govalidator.v4"
)
@ -529,6 +530,95 @@ func handleSetUpstreamDNS(w http.ResponseWriter, r *http.Request) {
}
}
func handleTestUpstreamDNS(w http.ResponseWriter, r *http.Request) {
body, err := ioutil.ReadAll(r.Body)
if err != nil {
errortext := fmt.Sprintf("Failed to read request body: %s", err)
log.Println(errortext)
http.Error(w, errortext, 400)
return
}
hosts := strings.Fields(string(body))
if len(hosts) == 0 {
errortext := fmt.Sprintf("No servers specified")
log.Println(errortext)
http.Error(w, errortext, http.StatusBadRequest)
return
}
result := map[string]string{}
for _, host := range hosts {
err := checkDNS(host)
if err != nil {
log.Println(err)
result[host] = err.Error()
} else {
result[host] = "OK"
}
}
json, err := json.Marshal(result)
if err != nil {
errortext := fmt.Sprintf("Unable to marshal status json: %s", err)
log.Println(errortext)
http.Error(w, errortext, http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "application/json")
_, err = w.Write(json)
if err != nil {
errortext := fmt.Sprintf("Couldn't write body: %s", err)
log.Println(errortext)
http.Error(w, errortext, http.StatusInternalServerError)
}
}
func checkDNS(host string) error {
host = appendPortIfMissing(host)
{
h, _, err := net.SplitHostPort(host)
if err != nil {
return err
}
ip := net.ParseIP(h)
if ip == nil {
return fmt.Errorf("Invalid DNS server field: %s", h)
}
}
req := dns.Msg{}
req.Id = dns.Id()
req.RecursionDesired = true
req.Question = []dns.Question{
{"google-public-dns-a.google.com.", dns.TypeA, dns.ClassINET},
}
resp, err := dns.Exchange(&req, host)
if err != nil {
return fmt.Errorf("Couldn't communicate with DNS server %s: %s", host, err)
}
if len(resp.Answer) != 1 {
return fmt.Errorf("DNS server %s returned wrong answer", host)
}
if t, ok := resp.Answer[0].(*dns.A); ok {
if !net.IPv4(8, 8, 8, 8).Equal(t.A) {
return fmt.Errorf("DNS server %s returned wrong answer: %v", host, t.A)
}
}
return nil
}
func appendPortIfMissing(input string) string {
_, _, err := net.SplitHostPort(input)
if err == nil {
return input
}
return net.JoinHostPort(input, "53")
}
func parseIPsOptionalPort(input string) []string {
fields := strings.Fields(input)
hosts := []string{}
@ -1309,6 +1399,7 @@ func registerControlHandlers() {
http.HandleFunc("/control/querylog_enable", optionalAuth(ensurePOST(handleQueryLogEnable)))
http.HandleFunc("/control/querylog_disable", optionalAuth(ensurePOST(handleQueryLogDisable)))
http.HandleFunc("/control/set_upstream_dns", optionalAuth(ensurePOST(handleSetUpstreamDNS)))
http.HandleFunc("/control/test_upstream_dns", optionalAuth(ensurePOST(handleTestUpstreamDNS)))
http.HandleFunc("/control/filtering/enable", optionalAuth(ensurePOST(handleFilteringEnable)))
http.HandleFunc("/control/filtering/disable", optionalAuth(ensurePOST(handleFilteringDisable)))
http.HandleFunc("/control/filtering/status", optionalAuth(ensureGET(handleFilteringStatus)))

View File

@ -160,6 +160,35 @@ paths:
responses:
200:
description: OK
/test_upstream_dns:
post:
tags:
- global
operationId: testUpstreamDNS
summary: 'Test upstream DNS'
consumes:
- text/plain
parameters:
- in: body
name: upstream
description: 'Upstream servers, separated by newline or space, port is optional after colon'
schema:
type: string
example: |
1.1.1.1
1.0.0.1
8.8.8.8 8.8.4.4
192.168.1.104:53535
responses:
200:
description: 'Status of testing each requested server, with "OK" meaning that server works, any other text means an error.'
examples:
application/json:
1.1.1.1: OK
1.0.0.1: OK
8.8.8.8: OK
8.8.4.4: OK
"192.168.1.104:53535": "Couldn't communicate with DNS server"
/stats_top:
get:
tags: