implement namesys resolvers (thanks to bren2010 for dns and proquint)

Author: whyrusleeping

dns.go

@@ -0,0 +1,33 @@
+package namesys
+
+import (
+	"net"
+	"strings"
+
+	u "github.com/jbenet/go-ipfs/util"
+)
+
+type DNSResolver struct {
+	// TODO: maybe some sort of caching?
+	// cache would need a timeout
+}
+
+func (r *DNSResolver) Resolve(name string) (string, error) {
+	txt, err := net.LookupTXT(name)
+	if err != nil {
+		return "", err
+	}
+
+	for _, t := range txt {
+		pair := strings.Split(t, "=")
+		if len(pair) < 2 {
+			// Log error?
+			u.DErr("Incorrectly formatted text record.")
+			continue
+		}
+		if pair[0] == name {
+			return pair[1], nil
+		}
+	}
+	return "", u.ErrNotFound
+}

entry.pb.go

@@ -0,0 +1,6 @@
+package namesys;
+
+message InpsEntry {
+	required bytes value = 1;
+	required bytes signature = 2;
+}

entry.proto

@@ -0,0 +1,5 @@
+package namesys
+
+type NSResolver interface {
+	Resolve(string) (string, error)
+}

nsresolver.go

@@ -0,0 +1,22 @@
+package namesys
+
+import (
+	"errors"
+
+	proquint "github.com/bren2010/proquint"
+)
+
+var _ = proquint.Encode
+
+type ProquintResolver struct{}
+
+func (r *ProquintResolver) Resolve(name string) (string, error) {
+	ok, err := proquint.IsProquint(name)
+	if err != nil {
+		return "", err
+	}
+	if !ok {
+		return "", errors.New("not a valid proquint string")
+	}
+	return string(proquint.Decode(name)), nil
+}

proquint.go

@@ -0,0 +1,21 @@
+package namesys
+
+import "strings"
+
+type MasterResolver struct {
+	dns     *DNSResolver
+	routing *RoutingResolver
+	pro     *ProquintResolver
+}
+
+func (mr *MasterResolver) Resolve(name string) (string, error) {
+	if strings.Contains(name, ".") {
+		return mr.dns.Resolve(name)
+	}
+
+	if strings.Contains(name, "-") {
+		return mr.pro.Resolve(name)
+	}
+
+	return mr.routing.Resolve(name)
+}

resolver.go

@@ -0,0 +1,77 @@
+package namesys
+
+import (
+	"fmt"
+	"time"
+
+	"code.google.com/p/goprotobuf/proto"
+
+	ci "github.com/jbenet/go-ipfs/crypto"
+	mdag "github.com/jbenet/go-ipfs/merkledag"
+	"github.com/jbenet/go-ipfs/routing"
+	u "github.com/jbenet/go-ipfs/util"
+	mh "github.com/jbenet/go-multihash"
+)
+
+// RoutingName is the de-serialized name structure that is stored (serialized)
+// in the routing system. Basically, a hash + a digital signature. (serialization can be
+// protobuf, or a simple binary format)
+type RoutingName struct {
+	Hash      u.Key
+	Signature []byte
+}
+
+// RoutingResolver implements NSResolver for the main IPFS SFS-like naming
+type RoutingResolver struct {
+	routing routing.IpfsRouting
+	dag     mdag.DAGService
+}
+
+func (r *RoutingResolver) Resolve(name string) (string, error) {
+	hash, err := mh.FromB58String(name)
+	if err != nil {
+		return "", err
+	}
+	// name should be a multihash. if it isn't, error out here.
+
+	// use the routing system to get the name.
+	// /ipns/<name>
+	h, err := u.Hash([]byte("ipns:" + name))
+	if err != nil {
+		return "", err
+	}
+
+	inpsKey := u.Key(h)
+	val, err := r.routing.GetValue(inpsKey, time.Second*10)
+	if err != nil {
+		return "", err
+	}
+
+	entry := new(InpsEntry)
+	err = proto.Unmarshal(val, entry)
+	if err != nil {
+		return "", err
+	}
+
+	// name should be a public key retrievable from ipfs
+	// /ipfs/<name>
+	key := u.Key(hash)
+	node, err := r.dag.Get(key)
+	if err != nil {
+		return "", err
+	}
+
+	// get PublicKey from node.Data
+	pk, err := ci.UnmarshalPublicKey(node.Data)
+	if err != nil {
+		return "", err
+	}
+
+	// check sig with pk
+	if ok, err := pk.Verify(entry.GetValue(), entry.GetSignature()); err != nil && ok {
+		return "", fmt.Errorf("Invalid value. Not signed by PrivateKey corresponding to %v", pk)
+	}
+
+	// ok sig checks out. this is a valid name.
+	return string(entry.GetValue()), nil
+}