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Forwarding plugin

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This commit is contained in:
Frank Denis 2018-01-17 09:44:03 +01:00
parent 1b38364e48
commit 96dadc7aca
8 changed files with 170 additions and 53 deletions
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49
README.md
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@ -8,30 +8,31 @@ A modern client implementation of the [DNSCrypt](https://github.com/DNSCrypt/dns
## Current status/features
| Features | dnscrypt-proxy 1.x | dnscrypt-proxy 2.x |
| ---------------------------------------------------------- | ---------------------------------------------------------------------------- | ------------------------------------------------------- |
| Status | Old PoC, barely maintained any more | Very new, but quickly evolving |
| Code quality | Big ugly mess | Readable, easy to work on |
| Reliability | Poor, due to completely broken handling of edge cases | Excellent |
| Security | Written in C, bundles patched versions from old branches of system libraries | Written in standard and portable Go |
| Dependencies | Specific versions of dnscrypt-proxy, libldns and libtool | None |
| Upstream connections using TCP | Catastrophic, requires client retries | Implemented as anyone would expect, works well with TOR |
| XChaCha20 support | Only if compiled with recent versions of libsodium | Yes, always available |
| Support of links with small MTU | Unreliable due to completely broken padding | Reliable, properly implemented |
| Support for multiple servers | Nonexistent | Yes, with automatic failover and load-balancing |
| Custom additions | C API, requires libldns for sanity | Simple Go structures using miekg/dns |
| AAAA blocking for IPv4-only networks | Yes | Yes |
| DNS caching | Yes, with ugly hacks for DNSSEC support | Yes, without ugly hacks |
| EDNS support | Broken with custom records | Yes |
| Asynchronous filters | Lol, no, filters block everything | Of course, thanks to Go |
| Session-local storage for extensions | Impossible | Yes |
| Multicore support | Nonexistent | Yes, thanks to Go |
| Efficient padding of queries | Couldn't be any worse | Yes |
| Multiple local sockets | Impossible | Of course. IPv4, IPv6, as many as you like |
| Automatically picks the fastest servers | Lol, it supports only one at a time, anyway | Yes, out of the box |
| Official, always up-to-date pre-built libraries | None | Yes, for many platforms. See below. |
| Automatically downloads and verifies servers lists | No. Requires custom scripts, cron jobs and dependencies (minisign) | Yes, built-in, including signature verification |
| Advanced expresions in blacklists (ads*.example[0-9]*.com) | No | Yes |
| Features | dnscrypt-proxy 1.x | dnscrypt-proxy 2.x |
| ----------------------------------------------------------- | ---------------------------------------------------------------------------- | ------------------------------------------------------- |
| Status | Old PoC, barely maintained any more | Very new, but quickly evolving |
| Code quality | Big ugly mess | Readable, easy to work on |
| Reliability | Poor, due to completely broken handling of edge cases | Excellent |
| Security | Written in C, bundles patched versions from old branches of system libraries | Written in standard and portable Go |
| Dependencies | Specific versions of dnscrypt-proxy, libldns and libtool | None |
| Upstream connections using TCP | Catastrophic, requires client retries | Implemented as anyone would expect, works well with TOR |
| XChaCha20 support | Only if compiled with recent versions of libsodium | Yes, always available |
| Support of links with small MTU | Unreliable due to completely broken padding | Reliable, properly implemented |
| Support for multiple servers | Nonexistent | Yes, with automatic failover and load-balancing |
| Custom additions | C API, requires libldns for sanity | Simple Go structures using miekg/dns |
| AAAA blocking for IPv4-only networks | Yes | Yes |
| DNS caching | Yes, with ugly hacks for DNSSEC support | Yes, without ugly hacks |
| EDNS support | Broken with custom records | Yes |
| Asynchronous filters | Lol, no, filters block everything | Of course, thanks to Go |
| Session-local storage for extensions | Impossible | Yes |
| Multicore support | Nonexistent | Yes, thanks to Go |
| Efficient padding of queries | Couldn't be any worse | Yes |
| Multiple local sockets | Impossible | Of course. IPv4, IPv6, as many as you like |
| Automatically picks the fastest servers | Lol, it supports only one at a time, anyway | Yes, out of the box |
| Official, always up-to-date pre-built libraries | None | Yes, for many platforms. See below. |
| Automatically downloads and verifies servers lists | No. Requires custom scripts, cron jobs and dependencies (minisign) | Yes, built-in, including signature verification |
| Advanced expressions in blacklists (ads*.example[0-9]*.com) | No | Yes |
| Forwarding with load balancing | No | Yes |
## Planned features

2
dnscrypt-proxy/config.go
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@ -26,6 +26,7 @@ type Config struct {
CacheMaxTTL uint32 `toml:"cache_max_ttl"`
QueryLog QueryLogConfig `toml:"query_log"`
BlockName BlockNameConfig `toml:"block_name"`
ForwardFile string `toml:"forwarding_rules"`
ServersConfig map[string]ServerConfig `toml:"servers"`
SourcesConfig map[string]SourceConfig `toml:"sources"`
}
@ -104,6 +105,7 @@ func ConfigLoad(proxy *Proxy, config_file string) error {
proxy.queryLogFile = config.QueryLog.File
proxy.queryLogFormat = config.QueryLog.Format
proxy.blockNameFile = config.BlockName.File
proxy.forwardFile = config.ForwardFile
if len(config.ServerNames) == 0 {
for serverName := range config.ServersConfig {
config.ServerNames = append(config.ServerNames, serverName)

50
dnscrypt-proxy/dnscrypt-proxy.toml
View File

@ -48,28 +48,12 @@ cert_refresh_delay = 30
block_ipv6 = false
############## Query logging ##############
############## Route queries for specific domains to a dedicated set of servers ##############
# Example map entries (one entry per line):
# example.com: 9.9.9.9
# example.net: 9.9.9.9,8.8.8.8
## Log client queries to a file
[query_log]
### Full path to the query log file
# file = "query.log"
### Query log format (currently supported: tsv and ltsv)
format = "tsv"
############## Pattern-based blocking (blacklists) ##############
# Blacklists are made of one pattern per line. Example of valid patterns:
# example.com
# *sex*
# ads.*
# ads*.example.*
# ads*.example[0-9]*.com
[block_name]
## Full path to the file of blocking rules
file = "blacklist.txt"
forwarding_rules = "forwarding-rules.txt"
############## DNS Cache ##############
@ -99,6 +83,30 @@ cache_max_ttl = 86400
cache_neg_ttl = 60
############## Query logging ##############
# Log client queries to a file
[query_log]
### Full path to the query log file
# file = "query.log"
### Query log format (currently supported: tsv and ltsv)
format = "tsv"
############## Pattern-based blocking (blacklists) ##############
# Blacklists are made of one pattern per line. Example of valid patterns:
# example.com
# *sex*
# ads.*
# ads*.example.*
# ads*.example[0-9]*.com
[block_name]
## Full path to the file of blocking rules
file = "blacklist.txt"
############## Servers ##############
## Remote lists of available servers

1
dnscrypt-proxy/main.go
View File

@ -31,6 +31,7 @@ type Proxy struct {
queryLogFile string
queryLogFormat string
blockNameFile string
forwardFile string
pluginsGlobals PluginsGlobals
}

10
dnscrypt-proxy/plugin_block_name.go
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@ -1,7 +1,6 @@
package main
import (
"fmt"
"io/ioutil"
"path/filepath"
"strings"
@ -54,23 +53,22 @@ func (plugin *PluginBlockName) Init(proxy *Proxy) error {
blockType := PluginBlockTypeNone
if isGlobCandidate(line) {
blockType = PluginBlockTypePattern
fmt.Println(line)
_, err := filepath.Match(line, "example.com")
if len(line) < 2 || err != nil {
dlog.Errorf("Syntax error in block rules at line %d", lineNo)
dlog.Errorf("Syntax error in block rules at line %d", 1+lineNo)
continue
}
} else if leadingStar && trailingStar {
blockType = PluginBlockTypeSubstring
if len(line) < 3 {
dlog.Errorf("Syntax error in block rules at line %d", lineNo)
dlog.Errorf("Syntax error in block rules at line %d", 1+lineNo)
continue
}
line = line[1 : len(line)-1]
} else if trailingStar {
blockType = PluginBlockTypePrefix
if len(line) < 2 {
dlog.Errorf("Syntax error in block rules at line %d", lineNo)
dlog.Errorf("Syntax error in block rules at line %d", 1+lineNo)
continue
}
line = line[:len(line)-1]
@ -84,7 +82,7 @@ func (plugin *PluginBlockName) Init(proxy *Proxy) error {
}
}
if len(line) == 0 {
dlog.Errorf("Syntax error in block rule at line %d", lineNo)
dlog.Errorf("Syntax error in block rule at line %d", 1+lineNo)
continue
}
line = strings.ToLower(line)

105
dnscrypt-proxy/plugin_forward.go Normal file
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@ -0,0 +1,105 @@
package main
import (
"fmt"
"io/ioutil"
"math/rand"
"net"
"strings"
"github.com/jedisct1/dlog"
"github.com/miekg/dns"
)
type PluginForwardEntry struct {
domain string
servers []string
}
type PluginForward struct {
forwardMap []PluginForwardEntry
}
func (plugin *PluginForward) Name() string {
return "forward"
}
func (plugin *PluginForward) Description() string {
return "Route queries matching specific domains to a dedicated set of servers"
}
func (plugin *PluginForward) Init(proxy *Proxy) error {
dlog.Noticef("Loading the set of forwarding rules from [%s]", proxy.forwardFile)
bin, err := ioutil.ReadFile(proxy.forwardFile)
if err != nil {
return err
}
for lineNo, line := range strings.Split(string(bin), "\n") {
parts := strings.SplitN(line, ":", 2)
if len(parts) == 0 || len(strings.Trim(parts[0], " \t\r")) == 0 {
continue
}
if len(parts) != 2 {
return fmt.Errorf("Syntax error for a forwarding rule at line %d. Expected syntax: example.com: 9.9.9.9,8.8.8.8", 1+lineNo)
}
domain := strings.ToLower(strings.Trim(parts[0], " \t\r"))
serversStr := strings.Trim(parts[1], " \t\r")
if len(domain) == 0 || len(serversStr) == 0 {
continue
}
var servers []string
for _, server := range strings.Split(serversStr, ",") {
server = strings.Trim(server, " \t\r")
if net.ParseIP(server) != nil {
server = fmt.Sprintf("%s:%d", server, 53)
}
servers = append(servers, server)
}
if len(servers) == 0 {
continue
}
plugin.forwardMap = append(plugin.forwardMap, PluginForwardEntry{
domain: domain, servers: servers,
})
}
return nil
}
func (plugin *PluginForward) Drop() error {
return nil
}
func (plugin *PluginForward) Reload() error {
return nil
}
func (plugin *PluginForward) Eval(pluginsState *PluginsState, msg *dns.Msg) error {
questions := msg.Question
if len(questions) != 1 {
return nil
}
question := strings.ToLower(StripTrailingDot(questions[0].Name))
questionLen := len(question)
var servers []string
for _, candidate := range plugin.forwardMap {
candidateLen := len(candidate.domain)
if candidateLen > questionLen {
continue
}
if question[questionLen-candidateLen:] == candidate.domain && (candidateLen == questionLen || (question[questionLen-candidateLen] == '.')) {
servers = candidate.servers
break
}
}
if len(servers) == 0 {
return nil
}
server := servers[rand.Intn(len(servers))]
respMsg, err := dns.Exchange(msg, server)
if err != nil {
return err
}
pluginsState.synthResponse = respMsg
pluginsState.action = PluginsActionSynth
return nil
}

4
dnscrypt-proxy/plugins.go
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@ -55,7 +55,9 @@ func InitPluginsGlobals(pluginsGlobals *PluginsGlobals, proxy *Proxy) error {
if proxy.cache {
*queryPlugins = append(*queryPlugins, Plugin(new(PluginCache)))
}
if len(proxy.forwardFile) != 0 {
*queryPlugins = append(*queryPlugins, Plugin(new(PluginForward)))
}
responsePlugins := &[]Plugin{}
if proxy.cache {
*responsePlugins = append(*responsePlugins, Plugin(new(PluginCacheResponse)))

2
dnscrypt-proxy/sources.go
View File

@ -136,7 +136,7 @@ func (source *Source) Parse() ([]RegisteredServer, error) {
continue
}
if len(record) < 14 {
return registeredServers, fmt.Errorf("Parse error at line %d", lineNo)
return registeredServers, fmt.Errorf("Parse error at line %d", 1+lineNo)
}
if lineNo == 0 {
continue