all: wait for network up before running

If ctrld setup the interface correctly, the interface DNS is set to
ctrld listener address. At boot time, the ctrld is not up yet, so it
would break the processing Control D config fetching.

Fixing this by waiting for network up before doing the query.

internal/controld/config.go

@@ -2,8 +2,10 @@ package controld
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
+	"net"
 	"net/http"
 	"time"
 )
@@ -13,6 +15,20 @@ const (
 	InvalidConfigCode = 40401
 )
 
+const bootstrapDNS = "76.76.2.0:53"
+
+var dialer = &net.Dialer{
+	Resolver: &net.Resolver{
+		PreferGo: true,
+		Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+			d := net.Dialer{
+				Timeout: 10 * time.Second,
+			}
+			return d.DialContext(ctx, "udp", bootstrapDNS)
+		},
+	},
+}
+
 // ResolverConfig represents Control D resolver data.
 type ResolverConfig struct {
 	DOH     string   `json:"doh"`
@@ -52,7 +68,14 @@ func FetchResolverConfig(uid string) (*ResolverConfig, error) {
 	q.Set("platform", "ctrld")
 	req.URL.RawQuery = q.Encode()
 	req.Header.Add("Content-Type", "application/json")
-	client := http.Client{Timeout: 5 * time.Second}
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+		return dialer.DialContext(ctx, network, addr)
+	}
+	client := http.Client{
+		Timeout:   10 * time.Second,
+		Transport: transport,
+	}
 	resp, err := client.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("client.Do: %w", err)