-
Notifications
You must be signed in to change notification settings - Fork 155
/
discovery.go
114 lines (102 loc) · 3.34 KB
/
discovery.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
// Copyright 2020 Anapaya Systems
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hiddenpath
import (
"context"
"net"
"github.com/scionproto/scion/pkg/addr"
"github.com/scionproto/scion/pkg/private/serrors"
"github.com/scionproto/scion/pkg/snet"
"github.com/scionproto/scion/pkg/snet/path"
)
// Servers is a list of discovered remote hidden segment server.
type Servers struct {
// Lookup is the list of lookup addresses.
Lookup []*net.UDPAddr
// Registration is the list of registration addresses.
Registration []*net.UDPAddr
}
// Discoverer can be used to find remote discovery services.
type Discoverer interface {
Discover(ctx context.Context, dsAddr net.Addr) (Servers, error)
}
// AddressResolver helps to resolve addresses in a remote AS.
type AddressResolver interface {
// Resolve creates an address with a path to the remote ISD-AS that is
// specified.
Resolve(context.Context, addr.IA) (net.Addr, error)
}
// RegistrationResolver resolves the address of a hidden segment registration
// server in an IA.
type RegistrationResolver struct {
Router snet.Router
Discoverer Discoverer
}
// Resolve resolves a hidden segment registration server in the remote IA.
func (r RegistrationResolver) Resolve(ctx context.Context, ia addr.IA) (net.Addr, error) {
return resolve(ctx, ia, r.Discoverer, r.Router, func(s Servers) (*net.UDPAddr, error) {
if len(s.Registration) == 0 {
return nil, serrors.New("no registration server found")
}
return s.Registration[0], nil
})
}
// LookupResolver resolves the address of a hidden segment lookup
// server in an IA.
type LookupResolver struct {
Router snet.Router
Discoverer Discoverer
}
// Resolve resolves a hidden segment lookup server in the remote IA.
func (r LookupResolver) Resolve(ctx context.Context, ia addr.IA) (net.Addr, error) {
return resolve(ctx, ia, r.Discoverer, r.Router, func(s Servers) (*net.UDPAddr, error) {
if len(s.Lookup) == 0 {
return nil, serrors.New("no lookup server found")
}
return s.Lookup[0], nil
})
}
func resolve(ctx context.Context, ia addr.IA, discoverer Discoverer, router snet.Router,
extractAddr func(Servers) (*net.UDPAddr, error)) (net.Addr, error) {
p, err := router.Route(ctx, ia)
if err != nil {
return nil, serrors.WrapStr("looking up path", err)
}
if p == nil {
return nil, serrors.WrapStr("no path found to remote", err)
}
dsAddr := &snet.SVCAddr{
IA: ia,
NextHop: p.UnderlayNextHop(),
Path: p.Dataplane(),
SVC: addr.SvcDS,
}
if dsAddr.Path == nil {
dsAddr.Path = path.Empty{}
}
hps, err := discoverer.Discover(ctx, dsAddr)
if err != nil {
return nil, serrors.WrapStr("discovering hidden path server", err)
}
a, err := extractAddr(hps)
if err != nil {
return nil, serrors.WithCtx(err, "isd_as", ia)
}
return &snet.UDPAddr{
IA: ia,
Host: a,
NextHop: dsAddr.NextHop,
Path: dsAddr.Path,
}, nil
}