summaryrefslogtreecommitdiffstats
path: root/vendor/golang.org/x/net/publicsuffix/list.go
blob: d56e9e762445787a5de69812d33804c1d92ad404 (plain) (blame)
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
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:generate go run gen.go

// Package publicsuffix provides a public suffix list based on data from
// https://publicsuffix.org/
//
// A public suffix is one under which Internet users can directly register
// names. It is related to, but different from, a TLD (top level domain).
//
// "com" is a TLD (top level domain). Top level means it has no dots.
//
// "com" is also a public suffix. Amazon and Google have registered different
// siblings under that domain: "amazon.com" and "google.com".
//
// "au" is another TLD, again because it has no dots. But it's not "amazon.au".
// Instead, it's "amazon.com.au".
//
// "com.au" isn't an actual TLD, because it's not at the top level (it has
// dots). But it is an eTLD (effective TLD), because that's the branching point
// for domain name registrars.
//
// Another name for "an eTLD" is "a public suffix". Often, what's more of
// interest is the eTLD+1, or one more label than the public suffix. For
// example, browsers partition read/write access to HTTP cookies according to
// the eTLD+1. Web pages served from "amazon.com.au" can't read cookies from
// "google.com.au", but web pages served from "maps.google.com" can share
// cookies from "www.google.com", so you don't have to sign into Google Maps
// separately from signing into Google Web Search. Note that all four of those
// domains have 3 labels and 2 dots. The first two domains are each an eTLD+1,
// the last two are not (but share the same eTLD+1: "google.com").
//
// All of these domains have the same eTLD+1:
//   - "www.books.amazon.co.uk"
//   - "books.amazon.co.uk"
//   - "amazon.co.uk"
//
// Specifically, the eTLD+1 is "amazon.co.uk", because the eTLD is "co.uk".
//
// There is no closed form algorithm to calculate the eTLD of a domain.
// Instead, the calculation is data driven. This package provides a
// pre-compiled snapshot of Mozilla's PSL (Public Suffix List) data at
// https://publicsuffix.org/
package publicsuffix // import "golang.org/x/net/publicsuffix"

// TODO: specify case sensitivity and leading/trailing dot behavior for
// func PublicSuffix and func EffectiveTLDPlusOne.

import (
	"fmt"
	"net/http/cookiejar"
	"strings"
)

// List implements the cookiejar.PublicSuffixList interface by calling the
// PublicSuffix function.
var List cookiejar.PublicSuffixList = list{}

type list struct{}

func (list) PublicSuffix(domain string) string {
	ps, _ := PublicSuffix(domain)
	return ps
}

func (list) String() string {
	return version
}

// PublicSuffix returns the public suffix of the domain using a copy of the
// publicsuffix.org database compiled into the library.
//
// icann is whether the public suffix is managed by the Internet Corporation
// for Assigned Names and Numbers. If not, the public suffix is either a
// privately managed domain (and in practice, not a top level domain) or an
// unmanaged top level domain (and not explicitly mentioned in the
// publicsuffix.org list). For example, "foo.org" and "foo.co.uk" are ICANN
// domains, "foo.dyndns.org" and "foo.blogspot.co.uk" are private domains and
// "cromulent" is an unmanaged top level domain.
//
// Use cases for distinguishing ICANN domains like "foo.com" from private
// domains like "foo.appspot.com" can be found at
// https://wiki.mozilla.org/Public_Suffix_List/Use_Cases
func PublicSuffix(domain string) (publicSuffix string, icann bool) {
	lo, hi := uint32(0), uint32(numTLD)
	s, suffix, icannNode, wildcard := domain, len(domain), false, false
loop:
	for {
		dot := strings.LastIndex(s, ".")
		if wildcard {
			icann = icannNode
			suffix = 1 + dot
		}
		if lo == hi {
			break
		}
		f := find(s[1+dot:], lo, hi)
		if f == notFound {
			break
		}

		u := uint32(nodes.get(f) >> (nodesBitsTextOffset + nodesBitsTextLength))
		icannNode = u&(1<<nodesBitsICANN-1) != 0
		u >>= nodesBitsICANN
		u = children.get(u & (1<<nodesBitsChildren - 1))
		lo = u & (1<<childrenBitsLo - 1)
		u >>= childrenBitsLo
		hi = u & (1<<childrenBitsHi - 1)
		u >>= childrenBitsHi
		switch u & (1<<childrenBitsNodeType - 1) {
		case nodeTypeNormal:
			suffix = 1 + dot
		case nodeTypeException:
			suffix = 1 + len(s)
			break loop
		}
		u >>= childrenBitsNodeType
		wildcard = u&(1<<childrenBitsWildcard-1) != 0
		if !wildcard {
			icann = icannNode
		}

		if dot == -1 {
			break
		}
		s = s[:dot]
	}
	if suffix == len(domain) {
		// If no rules match, the prevailing rule is "*".
		return domain[1+strings.LastIndex(domain, "."):], icann
	}
	return domain[suffix:], icann
}

const notFound uint32 = 1<<32 - 1

// find returns the index of the node in the range [lo, hi) whose label equals
// label, or notFound if there is no such node. The range is assumed to be in
// strictly increasing node label order.
func find(label string, lo, hi uint32) uint32 {
	for lo < hi {
		mid := lo + (hi-lo)/2
		s := nodeLabel(mid)
		if s < label {
			lo = mid + 1
		} else if s == label {
			return mid
		} else {
			hi = mid
		}
	}
	return notFound
}

// nodeLabel returns the label for the i'th node.
func nodeLabel(i uint32) string {
	x := nodes.get(i)
	length := x & (1<<nodesBitsTextLength - 1)
	x >>= nodesBitsTextLength
	offset := x & (1<<nodesBitsTextOffset - 1)
	return text[offset : offset+length]
}

// EffectiveTLDPlusOne returns the effective top level domain plus one more
// label. For example, the eTLD+1 for "foo.bar.golang.org" is "golang.org".
func EffectiveTLDPlusOne(domain string) (string, error) {
	if strings.HasPrefix(domain, ".") || strings.HasSuffix(domain, ".") || strings.Contains(domain, "..") {
		return "", fmt.Errorf("publicsuffix: empty label in domain %q", domain)
	}

	suffix, _ := PublicSuffix(domain)
	if len(domain) <= len(suffix) {
		return "", fmt.Errorf("publicsuffix: cannot derive eTLD+1 for domain %q", domain)
	}
	i := len(domain) - len(suffix) - 1
	if domain[i] != '.' {
		return "", fmt.Errorf("publicsuffix: invalid public suffix %q for domain %q", suffix, domain)
	}
	return domain[1+strings.LastIndex(domain[:i], "."):], nil
}

type uint32String string

func (u uint32String) get(i uint32) uint32 {
	off := i * 4
	return (uint32(u[off])<<24 |
		uint32(u[off+1])<<16 |
		uint32(u[off+2])<<8 |
		uint32(u[off+3]))
}

type uint40String string

func (u uint40String) get(i uint32) uint64 {
	off := uint64(i * (nodesBits / 8))
	return uint64(u[off])<<32 |
		uint64(u[off+1])<<24 |
		uint64(u[off+2])<<16 |
		uint64(u[off+3])<<8 |
		uint64(u[off+4])
}