* dnsfilter: major refactoring

* dnsfilter is controlled by package home, not dnsforward
* move HTTP handlers to dnsfilter/
* apply filtering settings without DNS server restart
* use only 1 goroutine for filters update
* apply new filters quickly (after they are ready to be used)

dnsfilter/rewrites.go

@@ -0,0 +1,93 @@
+// DNS Rewrites
+
+package dnsfilter
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+type rewriteEntryJSON struct {
+	Domain string `json:"domain"`
+	Answer string `json:"answer"`
+}
+
+func (d *Dnsfilter) handleRewriteList(w http.ResponseWriter, r *http.Request) {
+
+	arr := []*rewriteEntryJSON{}
+
+	d.confLock.Lock()
+	for _, ent := range d.Config.Rewrites {
+		jsent := rewriteEntryJSON{
+			Domain: ent.Domain,
+			Answer: ent.Answer,
+		}
+		arr = append(arr, &jsent)
+	}
+	d.confLock.Unlock()
+
+	w.Header().Set("Content-Type", "application/json")
+	err := json.NewEncoder(w).Encode(arr)
+	if err != nil {
+		httpError(r, w, http.StatusInternalServerError, "json.Encode: %s", err)
+		return
+	}
+}
+
+func (d *Dnsfilter) handleRewriteAdd(w http.ResponseWriter, r *http.Request) {
+
+	jsent := rewriteEntryJSON{}
+	err := json.NewDecoder(r.Body).Decode(&jsent)
+	if err != nil {
+		httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
+		return
+	}
+
+	ent := RewriteEntry{
+		Domain: jsent.Domain,
+		Answer: jsent.Answer,
+	}
+	d.confLock.Lock()
+	d.Config.Rewrites = append(d.Config.Rewrites, ent)
+	d.confLock.Unlock()
+	log.Debug("Rewrites: added element: %s -> %s [%d]",
+		ent.Domain, ent.Answer, len(d.Config.Rewrites))
+
+	d.Config.ConfigModified()
+}
+
+func (d *Dnsfilter) handleRewriteDelete(w http.ResponseWriter, r *http.Request) {
+
+	jsent := rewriteEntryJSON{}
+	err := json.NewDecoder(r.Body).Decode(&jsent)
+	if err != nil {
+		httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
+		return
+	}
+
+	entDel := RewriteEntry{
+		Domain: jsent.Domain,
+		Answer: jsent.Answer,
+	}
+	arr := []RewriteEntry{}
+	d.confLock.Lock()
+	for _, ent := range d.Config.Rewrites {
+		if ent == entDel {
+			log.Debug("Rewrites: removed element: %s -> %s", ent.Domain, ent.Answer)
+			continue
+		}
+		arr = append(arr, ent)
+	}
+	d.Config.Rewrites = arr
+	d.confLock.Unlock()
+
+	d.Config.ConfigModified()
+}
+
+func (d *Dnsfilter) registerRewritesHandlers() {
+	d.Config.HTTPRegister("GET", "/control/rewrite/list", d.handleRewriteList)
+	d.Config.HTTPRegister("POST", "/control/rewrite/add", d.handleRewriteAdd)
+	d.Config.HTTPRegister("POST", "/control/rewrite/delete", d.handleRewriteDelete)
+}