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Pull request: 3257 source directive

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Merge in DNS/adguard-home from 3257-ifaces-source to master

Updates #3257.

Squashed commit of the following:

commit 0b9b42bab731bbd048e97893cf209794ea014dfe
Merge: 530a1a23 e25a5329
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Mon Jun 28 16:53:36 2021 +0300

    Merge branch 'master' into 3257-ifaces-source

commit 530a1a23a601c5575c8dc5f6f97cd84801cf911b
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Jun 25 19:43:55 2021 +0300

    aghnet: imp code, add docs

commit 58de84821b93bcbb3df1834ba33fbad817201b1d
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Jun 25 13:34:43 2021 +0300

    aghnet: sup "source" directive

commit c0901abd5212902295e8ee546fad652092fdb5a8
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Thu Jun 24 16:46:03 2021 +0300

    aghos: mv func to aghnet
This commit is contained in:
Eugene Burkov
2021-06-28 17:02:45 +03:00
parent e25a532987
commit 28f34ca399
15 changed files with 229 additions and 82 deletions
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200
internal/aghnet/net_linux.go
View File

@@ -9,16 +9,132 @@ import (
"io"
"net"
"os"
"path/filepath"
"strings"
"github.com/AdguardTeam/AdGuardHome/internal/aghio"
"github.com/AdguardTeam/AdGuardHome/internal/aghos"
"github.com/AdguardTeam/AdGuardHome/internal/aghstrings"
"github.com/AdguardTeam/golibs/errors"
"github.com/google/renameio/maybe"
"golang.org/x/sys/unix"
)
// maxConfigFileSize is the maximum assumed length of the interface
// configuration file.
const maxConfigFileSize = 1024 * 1024
// recurrentChecker is used to check all the files which may include references
// for other ones.
type recurrentChecker struct {
// checker is the function to check if r's stream contains the desired
// attribute. It must return all the patterns for files which should
// also be checked and each of them should be valid for filepath.Glob
// function.
checker func(r io.Reader, desired string) (patterns []string, has bool, err error)
// initPath is the path of the first member in the sequence of checked
// files.
initPath string
}
// maxCheckedFileSize is the maximum length of the file that recurrentChecker
// may check.
const maxCheckedFileSize = 1024 * 1024
// checkFile tries to open and to check single file located on the sourcePath.
func (rc *recurrentChecker) checkFile(sourcePath, desired string) (
subsources []string,
has bool,
err error,
) {
var f *os.File
f, err = os.Open(sourcePath)
if err != nil {
return nil, false, err
}
defer func() { err = errors.WithDeferred(err, f.Close()) }()
var r io.Reader
r, err = aghio.LimitReader(f, maxCheckedFileSize)
if err != nil {
return nil, false, err
}
subsources, has, err = rc.checker(r, desired)
if err != nil {
return nil, false, err
}
if has {
return nil, true, nil
}
return subsources, has, nil
}
// handlePatterns parses the patterns and takes care of duplicates.
func (rc *recurrentChecker) handlePatterns(sourcesSet *aghstrings.Set, patterns []string) (
subsources []string,
err error,
) {
subsources = make([]string, 0, len(patterns))
for _, p := range patterns {
var matches []string
matches, err = filepath.Glob(p)
if err != nil {
return nil, fmt.Errorf("invalid pattern %q: %w", p, err)
}
for _, m := range matches {
if sourcesSet.Has(m) {
continue
}
sourcesSet.Add(m)
subsources = append(subsources, m)
}
}
return subsources, nil
}
// check walks through all the files searching for the desired attribute.
func (rc *recurrentChecker) check(desired string) (has bool, err error) {
var i int
sources := []string{rc.initPath}
defer func() {
if i >= len(sources) {
return
}
err = errors.Annotate(err, "checking %q: %w", sources[i])
}()
var patterns, subsources []string
// The slice of sources is separate from the set of sources to keep the
// order in which the files are walked.
for sourcesSet := aghstrings.NewSet(rc.initPath); i < len(sources); i++ {
patterns, has, err = rc.checkFile(sources[i], desired)
if err != nil {
if errors.Is(err, os.ErrNotExist) {
continue
}
return false, err
}
if has {
return true, nil
}
subsources, err = rc.handlePatterns(sourcesSet, patterns)
if err != nil {
return false, err
}
sources = append(sources, subsources...)
}
return false, nil
}
func ifaceHasStaticIP(ifaceName string) (has bool, err error) {
// TODO(a.garipov): Currently, this function returns the first
@@ -26,48 +142,34 @@ func ifaceHasStaticIP(ifaceName string) (has bool, err error) {
// /etc/network/interfaces doesn't, it will return true. Perhaps this
// is not the most desirable behavior.
for _, check := range []struct {
checker func(io.Reader, string) (bool, error)
filePath string
}{{
for _, rc := range []*recurrentChecker{{
checker: dhcpcdStaticConfig,
filePath: "/etc/dhcpcd.conf",
initPath: "/etc/dhcpcd.conf",
}, {
checker: ifacesStaticConfig,
filePath: "/etc/network/interfaces",
initPath: "/etc/network/interfaces",
}} {
var f *os.File
f, err = os.Open(check.filePath)
if err != nil {
// ErrNotExist can happen here if there is no such file.
// This is normal, as not every system uses those files.
if errors.Is(err, os.ErrNotExist) {
err = nil
continue
}
return false, err
}
defer func() { err = errors.WithDeferred(err, f.Close()) }()
var fileReader io.Reader
fileReader, err = aghio.LimitReader(f, maxConfigFileSize)
has, err = rc.check(ifaceName)
if err != nil {
return false, err
}
has, err = check.checker(fileReader, ifaceName)
if err != nil {
return false, err
if has {
return true, nil
}
return has, nil
}
return false, ErrNoStaticIPInfo
}
func canBindPrivilegedPorts() (can bool, err error) {
cnbs, err := unix.PrctlRetInt(unix.PR_CAP_AMBIENT, unix.PR_CAP_AMBIENT_IS_SET, unix.CAP_NET_BIND_SERVICE, 0, 0)
// Don't check the error because it's always nil on Linux.
adm, _ := aghos.HaveAdminRights()
return cnbs == 1 || adm, err
}
// findIfaceLine scans s until it finds the line that declares an interface with
// the given name. If findIfaceLine can't find the line, it returns false.
func findIfaceLine(s *bufio.Scanner, name string) (ok bool) {
@@ -84,11 +186,11 @@ func findIfaceLine(s *bufio.Scanner, name string) (ok bool) {
// dhcpcdStaticConfig checks if interface is configured by /etc/dhcpcd.conf to
// have a static IP.
func dhcpcdStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
func dhcpcdStaticConfig(r io.Reader, ifaceName string) (subsources []string, has bool, err error) {
s := bufio.NewScanner(r)
ifaceFound := findIfaceLine(s, ifaceName)
if !ifaceFound {
return false, s.Err()
return nil, false, s.Err()
}
for s.Scan() {
@@ -97,7 +199,7 @@ func dhcpcdStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
if len(fields) >= 2 &&
fields[0] == "static" &&
strings.HasPrefix(fields[1], "ip_address=") {
return true, s.Err()
return nil, true, s.Err()
}
if len(fields) > 0 && fields[0] == "interface" {
@@ -106,29 +208,41 @@ func dhcpcdStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
}
}
return false, s.Err()
return nil, false, s.Err()
}
// ifacesStaticConfig checks if interface is configured by
// /etc/network/interfaces to have a static IP.
func ifacesStaticConfig(r io.Reader, ifaceName string) (has bool, err error) {
// ifacesStaticConfig checks if the interface is configured by any file of
// /etc/network/interfaces format to have a static IP.
func ifacesStaticConfig(r io.Reader, ifaceName string) (subsources []string, has bool, err error) {
s := bufio.NewScanner(r)
for s.Scan() {
line := strings.TrimSpace(s.Text())
if len(line) == 0 || line[0] == '#' {
if aghstrings.IsCommentOrEmpty(line) {
continue
}
// TODO(e.burkov): As man page interfaces(5) says, a line may be
// extended across multiple lines by making the last character a
// backslash. Provide extended lines and "source-directory"
// stanzas support.
fields := strings.Fields(line)
fieldsNum := len(fields)
// Man page interfaces(5) declares that interface definition
// should consist of the key word "iface" followed by interface
// name, and method at fourth field.
if len(fields) >= 4 && fields[0] == "iface" && fields[1] == ifaceName && fields[3] == "static" {
return true, nil
if fieldsNum >= 4 &&
fields[0] == "iface" && fields[1] == ifaceName && fields[3] == "static" {
return nil, true, nil
}
if fieldsNum >= 2 && fields[0] == "source" {
subsources = append(subsources, fields[1])
}
}
return false, s.Err()
return subsources, false, s.Err()
}
// ifaceSetStaticIP configures the system to retain its current IP on the