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Pull request: dhcpd: wait for interfaces' ip addresses to appear

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Merge in DNS/adguard-home from 2304-dncp-backoff to master

Updates #2304.

Squashed commit of the following:

commit c9bff8b27c6b031d43a7dd98152adcde7f49fff1
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Nov 27 14:08:03 2020 +0300

    dhcpd: try for 5s instead of 10s

commit 983cf471832de0e7762b8b6e0a4ba9bb76ecadfc
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Nov 25 19:58:41 2020 +0300

    dhcpd: wait for interfaces' ip addresses to appear
This commit is contained in:
Ainar Garipov 2020-11-27 14:39:43 +03:00
parent f9e4e7b024
commit a6e18c4700
7 changed files with 365 additions and 172 deletions
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67
HACKING.md
View File

@ -1,8 +1,9 @@
# *AdGuardHome* Developer Guidelines
As of **2020-11-20**, this document is still a work-in-progress. Some of the
rules aren't enforced, and others might change. Still, this is a good place to
find out about how we **want** our code to look like.
As of **2020-11-27**, this document is a work-in-progress, but should still be
followed. Some of the rules aren't enforced as thoroughly or remain broken in
old code, but this is still the place to find out about what we **want** our
code to look like.
The rules are mostly sorted in the alphabetical order.
@ -31,27 +32,17 @@ The rules are mostly sorted in the alphabetical order.
## *Go*
* <https://github.com/golang/go/wiki/CodeReviewComments>.
### Code And Naming
* <https://github.com/golang/go/wiki/TestComments>.
* <https://go-proverbs.github.io/>
* Add an empty line before `break`, `continue`, and `return`, unless it's the
only statement in that block.
* Avoid `goto`.
* Avoid `init` and use explicit initialization functions instead.
* Avoid `new`, especially with structs.
* Document everything, including unexported top-level identifiers, to build
a habit of writing documentation.
* Constructors should validate their arguments and return meaningful errors.
As a corollary, avoid lazy initialization.
* Don't put variable names into any kind of quotes.
* Don't use naked `return`s.
* Don't use underscores in file and package names, unless they're build tags
@ -76,25 +67,34 @@ The rules are mostly sorted in the alphabetical order.
* Name the deferred errors (e.g. when closing something) `cerr`.
* No `goto`.
* No shadowing, since it can often lead to subtle bugs, especially with
errors.
* Prefer constants to variables where possible. Reduce global variables. Use
[constant errors] instead of `errors.New`.
* Put comments above the documented entity, **not** to the side, to improve
readability.
* Use `gofumpt --extra -s`.
**TODO(a.garipov):** Add to the linters.
* Use linters.
* Use named returns to improve readability of function signatures.
* Write logs and error messages in lowercase only to make it easier to `grep`
logs and error messages without using the `-i` flag.
[constant errors]: https://dave.cheney.net/2016/04/07/constant-errors
[Linus said]: https://www.kernel.org/doc/html/v4.17/process/coding-style.html#indentation
### Commenting
* See also the *Text, Including Comments* section below.
* Document everything, including unexported top-level identifiers, to build
a habit of writing documentation.
* Don't put identifiers into any kind of quotes.
* Put comments above the documented entity, **not** to the side, to improve
readability.
* When a method implements an interface, start the doc comment with the
standard template:
@ -105,8 +105,14 @@ The rules are mostly sorted in the alphabetical order.
}
```
* Write logs and error messages in lowercase only to make it easier to `grep`
logs and error messages without using the `-i` flag.
### Formatting
* Add an empty line before `break`, `continue`, `fallthrough`, and `return`,
unless it's the only statement in that block.
* Use `gofumpt --extra -s`.
**TODO(a.garipov):** Add to the linters.
* Write slices of struct like this:
@ -123,8 +129,13 @@ The rules are mostly sorted in the alphabetical order.
}}
```
[constant errors]: https://dave.cheney.net/2016/04/07/constant-errors
[Linus said]: https://www.kernel.org/doc/html/v4.17/process/coding-style.html#indentation
### Recommended Reading
* <https://github.com/golang/go/wiki/CodeReviewComments>.
* <https://github.com/golang/go/wiki/TestComments>.
* <https://go-proverbs.github.io/>
## *Markdown*

4
internal/dhcpd/check_other_dhcp.go
View File

@ -26,7 +26,7 @@ func CheckIfOtherDHCPServersPresentV4(ifaceName string) (bool, error) {
return false, fmt.Errorf("couldn't find interface by name %s: %w", ifaceName, err)
}
ifaceIPNet, err := ifaceIPv4Addrs(iface)
ifaceIPNet, err := ifaceIPAddrs(iface, ipVersion4)
if err != nil {
return false, fmt.Errorf("getting ipv4 addrs for iface %s: %w", ifaceName, err)
}
@ -161,7 +161,7 @@ func CheckIfOtherDHCPServersPresentV6(ifaceName string) (bool, error) {
return false, fmt.Errorf("dhcpv6: net.InterfaceByName: %s: %w", ifaceName, err)
}
ifaceIPNet, err := ifaceIPv6Addrs(iface)
ifaceIPNet, err := ifaceIPAddrs(iface, ipVersion6)
if err != nil {
return false, fmt.Errorf("getting ipv6 addrs for iface %s: %w", ifaceName, err)
}

46
internal/dhcpd/v4.go
View File

@ -16,7 +16,9 @@ import (
"github.com/insomniacslk/dhcp/dhcpv4/server4"
)
// v4Server - DHCPv4 server
// v4Server is a DHCPv4 server.
//
// TODO(a.garipov): Think about unifying this and v6Server.
type v4Server struct {
srv *server4.Server
leasesLock sync.Mutex
@ -560,27 +562,6 @@ func (s *v4Server) packetHandler(conn net.PacketConn, peer net.Addr, req *dhcpv4
}
}
// ifaceIPv4Addrs returns the interface's IPv4 addresses.
func ifaceIPv4Addrs(iface *net.Interface) (ips []net.IP, err error) {
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, a := range addrs {
ipnet, ok := a.(*net.IPNet)
if !ok {
continue
}
if ip := ipnet.IP.To4(); ip != nil {
ips = append(ips, ip)
}
}
return ips, nil
}
// Start starts the IPv4 DHCP server.
func (s *v4Server) Start() error {
if !s.conf.Enabled {
@ -595,26 +576,9 @@ func (s *v4Server) Start() error {
log.Debug("dhcpv4: starting...")
dnsIPAddrs, err := ifaceIPv4Addrs(iface)
dnsIPAddrs, err := ifaceDNSIPAddrs(iface, ipVersion4, defaultMaxAttempts, defaultBackoff)
if err != nil {
return fmt.Errorf("dhcpv4: getting ipv4 addrs for iface %s: %w", ifaceName, err)
}
switch len(dnsIPAddrs) {
case 0:
log.Debug("dhcpv4: no ipv4 address for interface %s", iface.Name)
return nil
case 1:
// Some Android devices use 8.8.8.8 if there is no secondary DNS
// server. Fix that by setting the secondary DNS address to our
// address as well.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/1708.
log.Debug("dhcpv4: setting secondary dns ip to iself for interface %s", iface.Name)
dnsIPAddrs = append(dnsIPAddrs, dnsIPAddrs[0])
default:
// Go on.
return fmt.Errorf("dhcpv4: interface %s: %w", ifaceName, err)
}
s.conf.dnsIPAddrs = dnsIPAddrs

123
internal/dhcpd/v46.go Normal file
View File

@ -0,0 +1,123 @@
package dhcpd
import (
"fmt"
"net"
"time"
"github.com/AdguardTeam/golibs/log"
)
// ipVersion is a documentational alias for int. Use it when the integer means
// IP version.
type ipVersion = int
// IP version constants.
const (
ipVersion4 ipVersion = 4
ipVersion6 ipVersion = 6
)
// netIface is the interface for network interface methods.
type netIface interface {
Addrs() ([]net.Addr, error)
}
// ifaceIPAddrs returns the interface's IP addresses.
func ifaceIPAddrs(iface netIface, ipv ipVersion) (ips []net.IP, err error) {
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, a := range addrs {
var ip net.IP
switch a := a.(type) {
case *net.IPAddr:
ip = a.IP
case *net.IPNet:
ip = a.IP
default:
continue
}
// Assume that net.(*Interface).Addrs can only return valid IPv4
// and IPv6 addresses. Thus, if it isn't an IPv4 address, it
// must be an IPv6 one.
switch ipv {
case ipVersion4:
if ip4 := ip.To4(); ip4 != nil {
ips = append(ips, ip4)
}
case ipVersion6:
if ip6 := ip.To4(); ip6 == nil {
ips = append(ips, ip)
}
default:
return nil, fmt.Errorf("invalid ip version %d", ipv)
}
}
return ips, nil
}
// Currently used defaults for ifaceDNSAddrs.
const (
defaultMaxAttempts int = 10
defaultBackoff time.Duration = 500 * time.Millisecond
)
// ifaceDNSIPAddrs returns IP addresses of the interface suitable to send to
// clients as DNS addresses. If err is nil, addrs contains either no addresses
// or at least two.
//
// It makes up to maxAttempts attempts to get the addresses if there are none,
// each time using the provided backoff. Sometimes an interface needs a few
// seconds to really ititialize.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/2304.
func ifaceDNSIPAddrs(
iface netIface,
ipv ipVersion,
maxAttempts int,
backoff time.Duration,
) (addrs []net.IP, err error) {
var n int
waitForIP:
for n = 1; n <= maxAttempts; n++ {
addrs, err = ifaceIPAddrs(iface, ipv)
if err != nil {
return nil, fmt.Errorf("getting ip addrs: %w", err)
}
switch len(addrs) {
case 0:
log.Debug("dhcpv%d: attempt %d: no ip addresses", ipv, n)
time.Sleep(backoff)
case 1:
// Some Android devices use 8.8.8.8 if there is not
// a secondary DNS server. Fix that by setting the
// secondary DNS address to the same address.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/1708.
log.Debug("dhcpv%d: setting secondary dns ip to itself", ipv)
addrs = append(addrs, addrs[0])
fallthrough
default:
break waitForIP
}
}
if len(addrs) == 0 {
// Don't return errors in case the users want to try and enable
// the DHCP server later.
log.Error("dhcpv%d: no ip address for interface after %d attempts and %s", ipv, n, time.Duration(n)*backoff)
} else {
log.Debug("dhcpv%d: got addresses %s after %d attempts", ipv, addrs, n)
}
return addrs, nil
}

189
internal/dhcpd/v46_test.go Normal file
View File

@ -0,0 +1,189 @@
package dhcpd
import (
"errors"
"net"
"testing"
"github.com/AdguardTeam/AdGuardHome/internal/agherr"
"github.com/stretchr/testify/assert"
)
type fakeIface struct {
addrs []net.Addr
err error
}
// Addrs implements the netIface interface for *fakeIface.
func (iface *fakeIface) Addrs() (addrs []net.Addr, err error) {
if iface.err != nil {
return nil, iface.err
}
return iface.addrs, nil
}
func TestIfaceIPAddrs(t *testing.T) {
const errTest agherr.Error = "test error"
ip4 := net.IP{1, 2, 3, 4}
addr4 := &net.IPNet{IP: ip4}
ip6 := net.IP{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6}
addr6 := &net.IPNet{IP: ip6}
testCases := []struct {
name string
iface netIface
ipv ipVersion
want []net.IP
wantErr error
}{{
name: "ipv4_success",
iface: &fakeIface{addrs: []net.Addr{addr4}, err: nil},
ipv: ipVersion4,
want: []net.IP{ip4},
wantErr: nil,
}, {
name: "ipv4_success_with_ipv6",
iface: &fakeIface{addrs: []net.Addr{addr6, addr4}, err: nil},
ipv: ipVersion4,
want: []net.IP{ip4},
wantErr: nil,
}, {
name: "ipv4_error",
iface: &fakeIface{addrs: []net.Addr{addr4}, err: errTest},
ipv: ipVersion4,
want: nil,
wantErr: errTest,
}, {
name: "ipv6_success",
iface: &fakeIface{addrs: []net.Addr{addr6}, err: nil},
ipv: ipVersion6,
want: []net.IP{ip6},
wantErr: nil,
}, {
name: "ipv6_success_with_ipv4",
iface: &fakeIface{addrs: []net.Addr{addr6, addr4}, err: nil},
ipv: ipVersion6,
want: []net.IP{ip6},
wantErr: nil,
}, {
name: "ipv6_error",
iface: &fakeIface{addrs: []net.Addr{addr6}, err: errTest},
ipv: ipVersion6,
want: nil,
wantErr: errTest,
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
got, gotErr := ifaceIPAddrs(tc.iface, tc.ipv)
assert.Equal(t, tc.want, got)
assert.True(t, errors.Is(gotErr, tc.wantErr))
})
}
}
type waitingFakeIface struct {
addrs []net.Addr
err error
n int
}
// Addrs implements the netIface interface for *waitingFakeIface.
func (iface *waitingFakeIface) Addrs() (addrs []net.Addr, err error) {
if iface.err != nil {
return nil, iface.err
}
if iface.n == 0 {
return iface.addrs, nil
}
iface.n--
return nil, nil
}
func TestIfaceDNSIPAddrs(t *testing.T) {
const errTest agherr.Error = "test error"
ip4 := net.IP{1, 2, 3, 4}
addr4 := &net.IPNet{IP: ip4}
ip6 := net.IP{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6}
addr6 := &net.IPNet{IP: ip6}
testCases := []struct {
name string
iface netIface
ipv ipVersion
want []net.IP
wantErr error
}{{
name: "ipv4_success",
iface: &fakeIface{addrs: []net.Addr{addr4}, err: nil},
ipv: ipVersion4,
want: []net.IP{ip4, ip4},
wantErr: nil,
}, {
name: "ipv4_success_with_ipv6",
iface: &fakeIface{addrs: []net.Addr{addr6, addr4}, err: nil},
ipv: ipVersion4,
want: []net.IP{ip4, ip4},
wantErr: nil,
}, {
name: "ipv4_error",
iface: &fakeIface{addrs: []net.Addr{addr4}, err: errTest},
ipv: ipVersion4,
want: nil,
wantErr: errTest,
}, {
name: "ipv4_wait",
iface: &waitingFakeIface{
addrs: []net.Addr{addr4},
err: nil,
n: 1,
},
ipv: ipVersion4,
want: []net.IP{ip4, ip4},
wantErr: nil,
}, {
name: "ipv6_success",
iface: &fakeIface{addrs: []net.Addr{addr6}, err: nil},
ipv: ipVersion6,
want: []net.IP{ip6, ip6},
wantErr: nil,
}, {
name: "ipv6_success_with_ipv4",
iface: &fakeIface{addrs: []net.Addr{addr6, addr4}, err: nil},
ipv: ipVersion6,
want: []net.IP{ip6, ip6},
wantErr: nil,
}, {
name: "ipv6_error",
iface: &fakeIface{addrs: []net.Addr{addr6}, err: errTest},
ipv: ipVersion6,
want: nil,
wantErr: errTest,
}, {
name: "ipv6_wait",
iface: &waitingFakeIface{
addrs: []net.Addr{addr6},
err: nil,
n: 1,
},
ipv: ipVersion6,
want: []net.IP{ip6, ip6},
wantErr: nil,
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
got, gotErr := ifaceDNSIPAddrs(tc.iface, tc.ipv, 2, 0)
assert.Equal(t, tc.want, got)
assert.True(t, errors.Is(gotErr, tc.wantErr))
})
}
}

53
internal/dhcpd/v6.go
View File

@ -17,7 +17,9 @@ import (
const valueIAID = "ADGH" // value for IANA.ID
// v6Server - DHCPv6 server
// v6Server is a DHCPv6 server.
//
// TODO(a.garipov): Think about unifying this and v4Server.
type v6Server struct {
srv *server6.Server
leasesLock sync.Mutex
@ -537,34 +539,6 @@ func (s *v6Server) packetHandler(conn net.PacketConn, peer net.Addr, req dhcpv6.
}
}
type netIface interface {
Addrs() ([]net.Addr, error)
}
// ifaceIPv6Addrs returns the interface's IPv6 addresses.
func ifaceIPv6Addrs(iface netIface) (ips []net.IP, err error) {
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, a := range addrs {
ipnet, ok := a.(*net.IPNet)
if !ok {
continue
}
if ip := ipnet.IP.To4(); ip == nil {
// Assume that net.(*Interface).Addrs can only return
// valid IPv4 and IPv6 addresses. Since this isn't an
// IPv4 address, it must be an IPv6 one.
ips = append(ips, ipnet.IP)
}
}
return ips, nil
}
// initialize RA module
func (s *v6Server) initRA(iface *net.Interface) error {
// choose the source IP address - should be link-local-unicast
@ -598,24 +572,11 @@ func (s *v6Server) Start() error {
return fmt.Errorf("dhcpv6: finding interface %s by name: %w", ifaceName, err)
}
log.Debug("dhcpv4: starting...")
log.Debug("dhcpv6: starting...")
dnsIPAddrs, err := ifaceIPv6Addrs(iface)
dnsIPAddrs, err := ifaceDNSIPAddrs(iface, ipVersion6, defaultMaxAttempts, defaultBackoff)
if err != nil {
return fmt.Errorf("dhcpv6: getting ipv6 addrs for iface %s: %w", ifaceName, err)
}
switch len(dnsIPAddrs) {
case 0:
log.Debug("dhcpv6: no ipv6 address for interface %s", iface.Name)
return nil
case 1:
// See the comment in (*v4Server).Start.
log.Debug("dhcpv6: setting secondary dns ip to iself for interface %s", iface.Name)
dnsIPAddrs = append(dnsIPAddrs, dnsIPAddrs[0])
default:
// Go on.
return fmt.Errorf("dhcpv6: interface %s: %w", ifaceName, err)
}
s.conf.dnsIPAddrs = dnsIPAddrs
@ -631,7 +592,7 @@ func (s *v6Server) Start() error {
return nil
}
log.Debug("DHCPv6: starting...")
log.Debug("dhcpv6: listening...")
if len(iface.HardwareAddr) != 6 {
return fmt.Errorf("dhcpv6: invalid MAC %s", iface.HardwareAddr)

55
internal/dhcpd/v6_test.go
View File

@ -6,7 +6,6 @@ import (
"net"
"testing"
"github.com/AdguardTeam/AdGuardHome/internal/agherr"
"github.com/insomniacslk/dhcp/dhcpv6"
"github.com/insomniacslk/dhcp/iana"
"github.com/stretchr/testify/assert"
@ -224,57 +223,3 @@ func TestV6GetDynamicLease(t *testing.T) {
assert.True(t, ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2001::2")))
assert.True(t, ip6InRange(net.ParseIP("2001::2"), net.ParseIP("2001::3")))
}
type fakeIface struct {
addrs []net.Addr
err error
}
// Addrs implements the netIface interface for *fakeIface.
func (iface *fakeIface) Addrs() (addrs []net.Addr, err error) {
if iface.err != nil {
return nil, iface.err
}
return iface.addrs, nil
}
func TestIfaceIPv6Addrs(t *testing.T) {
ip := net.IP{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6}
ip4 := net.IP{1, 2, 3, 4}
addr := &net.IPNet{IP: ip}
errTest := agherr.Error("test error")
testCases := []struct {
name string
iface netIface
want []net.IP
wantErr error
}{{
name: "success",
iface: &fakeIface{addrs: []net.Addr{addr}, err: nil},
want: []net.IP{ip},
wantErr: nil,
}, {
name: "success_with_ipv4",
iface: &fakeIface{
addrs: []net.Addr{addr, &net.IPNet{IP: ip4}},
err: nil,
},
want: []net.IP{ip},
wantErr: nil,
}, {
name: "error",
iface: &fakeIface{addrs: []net.Addr{addr}, err: errTest},
want: nil,
wantErr: errTest,
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
got, gotErr := ifaceIPv6Addrs(tc.iface)
assert.Equal(t, tc.want, got)
assert.Equal(t, tc.wantErr, gotErr)
})
}
}