add support for a proxy dialer

libp2p · Aug 2, 2023 · 0945776 · 0945776
1 parent 1897e7c
commit 0945776
Show file tree

Hide file tree

Showing 2 changed files with 26 additions and 12 deletions.
diff --git a/request.go b/request.go
@@ -9,6 +9,7 @@ import (
 	"net/http"
 
 	"github.com/miekg/dns"
+	"golang.org/x/net/proxy"
 
 	logging "github.com/ipfs/go-log/v2"
 )
@@ -19,7 +20,7 @@ const (
 
 var log = logging.Logger("doh")
 
-func doRequest(ctx context.Context, url string, m *dns.Msg) (*dns.Msg, error) {
+func doRequest(ctx context.Context, url string, m *dns.Msg, dialer proxy.Dialer) (*dns.Msg, error) {
 	data, err := m.Pack()
 	if err != nil {
 		return nil, err
@@ -34,14 +35,18 @@ func doRequest(ctx context.Context, url string, m *dns.Msg) (*dns.Msg, error) {
 	req.Header.Set("Accept", dohMimeType)
 
 	req = req.WithContext(ctx)
-
-	resp, err := http.DefaultClient.Do(req)
+	client := http.DefaultClient
+	if dialer != nil {
+		client = &http.Client{Transport: &http.Transport{Dial: dialer.Dial}}
+	}
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, err
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
+		fmt.Println(resp.Status, resp.StatusCode)
 		return nil, fmt.Errorf("HTTP error: %q [%d]", resp.Status, resp.StatusCode)
 	}
 
@@ -62,13 +67,13 @@ func doRequest(ctx context.Context, url string, m *dns.Msg) (*dns.Msg, error) {
 	return r, nil
 }
 
-func doRequestA(ctx context.Context, url string, domain string) ([]net.IPAddr, uint32, error) {
+func doRequestA(ctx context.Context, url string, domain string, dialer proxy.Dialer) ([]net.IPAddr, uint32, error) {
 	fqdn := dns.Fqdn(domain)
 
 	m := new(dns.Msg)
 	m.SetQuestion(fqdn, dns.TypeA)
 
-	r, err := doRequest(ctx, url, m)
+	r, err := doRequest(ctx, url, m, dialer)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -90,13 +95,13 @@ func doRequestA(ctx context.Context, url string, domain string) ([]net.IPAddr, u
 	return result, ttl, nil
 }
 
-func doRequestAAAA(ctx context.Context, url string, domain string) ([]net.IPAddr, uint32, error) {
+func doRequestAAAA(ctx context.Context, url string, domain string, dialer proxy.Dialer) ([]net.IPAddr, uint32, error) {
 	fqdn := dns.Fqdn(domain)
 
 	m := new(dns.Msg)
 	m.SetQuestion(fqdn, dns.TypeAAAA)
 
-	r, err := doRequest(ctx, url, m)
+	r, err := doRequest(ctx, url, m, dialer)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -119,13 +124,13 @@ func doRequestAAAA(ctx context.Context, url string, domain string) ([]net.IPAddr
 	return result, ttl, nil
 }
 
-func doRequestTXT(ctx context.Context, url string, domain string) ([]string, uint32, error) {
+func doRequestTXT(ctx context.Context, url string, domain string, dialer proxy.Dialer) ([]string, uint32, error) {
 	fqdn := dns.Fqdn(domain)
 
 	m := new(dns.Msg)
 	m.SetQuestion(fqdn, dns.TypeTXT)
 
-	r, err := doRequest(ctx, url, m)
+	r, err := doRequest(ctx, url, m, dialer)
 	if err != nil {
 		return nil, 0, err
 	}

diff --git a/resolver.go b/resolver.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/miekg/dns"
+	"golang.org/x/net/proxy"
 
 	madns "github.com/multiformats/go-multiaddr-dns"
 )
@@ -21,6 +22,7 @@ type Resolver struct {
 	ipCache     map[string]ipAddrEntry
 	txtCache    map[string]txtEntry
 	maxCacheTTL time.Duration
+	dialer      proxy.Dialer
 }
 
 type ipAddrEntry struct {
@@ -51,6 +53,13 @@ func WithCacheDisabled() Option {
 	}
 }
 
+func WithDialer(dialer proxy.Dialer) Option {
+	return func(tr *Resolver) error {
+		tr.dialer = dialer
+		return nil
+	}
+}
+
 func NewResolver(url string, opts ...Option) (*Resolver, error) {
 	if !strings.HasPrefix(url, "https:") {
 		url = "https://" + url
@@ -88,12 +97,12 @@ func (r *Resolver) LookupIPAddr(ctx context.Context, domain string) (result []ne
 
 	resch := make(chan response, 2)
 	go func() {
-		ip4, ttl, err := doRequestA(ctx, r.url, domain)
+		ip4, ttl, err := doRequestA(ctx, r.url, domain, r.dialer)
 		resch <- response{ip4, ttl, err}
 	}()
 
 	go func() {
-		ip6, ttl, err := doRequestAAAA(ctx, r.url, domain)
+		ip6, ttl, err := doRequestAAAA(ctx, r.url, domain, r.dialer)
 		resch <- response{ip6, ttl, err}
 	}()
 
@@ -121,7 +130,7 @@ func (r *Resolver) LookupTXT(ctx context.Context, domain string) ([]string, erro
 		return result, nil
 	}
 
-	result, ttl, err := doRequestTXT(ctx, r.url, domain)
+	result, ttl, err := doRequestTXT(ctx, r.url, domain, r.dialer)
 	if err != nil {
 		return nil, err
 	}