mirror of https://github.com/0xERR0R/blocky.git
125 lines
3.2 KiB
Go
125 lines
3.2 KiB
Go
package resolver
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import (
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"fmt"
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"strings"
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"github.com/0xERR0R/blocky/config"
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"github.com/0xERR0R/blocky/model"
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"github.com/0xERR0R/blocky/util"
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"github.com/miekg/dns"
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"github.com/sirupsen/logrus"
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)
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// ConditionalUpstreamResolver delegates DNS question to other DNS resolver dependent on domain name in question
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type ConditionalUpstreamResolver struct {
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NextResolver
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mapping map[string]Resolver
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}
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// NewConditionalUpstreamResolver returns new resolver instance
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func NewConditionalUpstreamResolver(cfg config.ConditionalUpstreamConfig,
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bootstrap *Bootstrap) (ChainedResolver, error) {
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m := make(map[string]Resolver, len(cfg.Mapping.Upstreams))
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for domain, upstream := range cfg.Mapping.Upstreams {
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upstreams := make(map[string][]config.Upstream)
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upstreams[upstreamDefaultCfgName] = upstream
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r, err := NewParallelBestResolver(upstreams, bootstrap)
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if err != nil {
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return nil, err
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}
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m[strings.ToLower(domain)] = r
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}
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return &ConditionalUpstreamResolver{mapping: m}, nil
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}
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// Configuration returns current configuration
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func (r *ConditionalUpstreamResolver) Configuration() (result []string) {
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if len(r.mapping) > 0 {
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for key, val := range r.mapping {
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result = append(result, fmt.Sprintf("%s = \"%s\"", key, val))
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}
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} else {
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result = []string{"deactivated"}
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}
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return
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}
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func (r *ConditionalUpstreamResolver) processRequest(request *model.Request) (bool, *model.Response, error) {
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domainFromQuestion := util.ExtractDomain(request.Req.Question[0])
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domain := domainFromQuestion
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if strings.Contains(domainFromQuestion, ".") {
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// try with domain with and without sub-domains
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for len(domain) > 0 {
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if resolver, found := r.mapping[domain]; found {
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resp, err := r.internalResolve(resolver, domainFromQuestion, domain, request)
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return true, resp, err
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}
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if i := strings.Index(domain, "."); i >= 0 {
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domain = domain[i+1:]
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} else {
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break
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}
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}
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} else if resolver, found := r.mapping["."]; found {
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resp, err := r.internalResolve(resolver, domainFromQuestion, domain, request)
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return true, resp, err
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}
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return false, nil, nil
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}
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// Resolve uses the conditional resolver to resolve the query
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func (r *ConditionalUpstreamResolver) Resolve(request *model.Request) (*model.Response, error) {
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logger := withPrefix(request.Log, "conditional_resolver")
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if len(r.mapping) > 0 {
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resolved, resp, err := r.processRequest(request)
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if resolved {
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return resp, err
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}
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}
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logger.WithField("next_resolver", Name(r.next)).Trace("go to next resolver")
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return r.next.Resolve(request)
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}
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func (r *ConditionalUpstreamResolver) internalResolve(reso Resolver, doFQ, do string,
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req *model.Request) (*model.Response, error) {
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// internal request resolution
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logger := withPrefix(req.Log, "conditional_resolver")
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req.Req.Question[0].Name = dns.Fqdn(doFQ)
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response, err := reso.Resolve(req)
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if err == nil {
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response.Reason = "CONDITIONAL"
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response.RType = model.ResponseTypeCONDITIONAL
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response.Res.Question[0].Name = req.Req.Question[0].Name
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}
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var answer string
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if response != nil {
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answer = util.AnswerToString(response.Res.Answer)
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}
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logger.WithFields(logrus.Fields{
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"answer": answer,
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"domain": do,
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"upstream": reso,
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}).Debugf("received response from conditional upstream")
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return response, err
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}
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