[go] fix: get network card interface in Android 11 environment
Gerrit Bot (Gerrit)
Gerrit Bot has uploaded this change for review.
fix: get network card interface in Android 11 environment
For https://github.com/golang/go/issues/40569
Fix: In response to the modifications made to the permissions for accessing system MAC addresses in Android 11, ordinary applications encounter several main issues when using NETLINK sockets:
- Not allowing bind operations on `NETLINK` sockets.
- Not permitting the use of the `RTM_GETLINK` functionality.
For detailed information, please refer to: https://developer.android.com/training/articles/user-data-ids#mac-11-plus
As a result of the aforementioned reasons, using `net.Interfaces()` and `net.InterfaceAddrs()` from the Go net package in the Android environment leads to the `route ip+net: netlinkrib: permission denied` error.
You can find specific issue details here: https://github.com/golang/go/issues/40569
To address the issue of using the Go net package in the Android environment, we have made partial modifications to its source code to ensure proper functionality on Android.
I have fully resolved the issues with `net.InterfaceAddrs()`.
However, for `net.Interfaces()`, we have only addressed some problems, as the following issues still remain:
- It can only return interfaces with IP addresses.
- It cannot return hardware MAC addresses.
Nevertheless, the fixed `net.Interfaces()` function now aligns with the Android API's `NetworkInterface.getNetworkInterfaces()` and can be used normally in most scenarios.
The specific fix logic includes:
Removing the `Bind()` operation on `Netlink` sockets in the `NetlinkRIB()` function.
Using `ioctl` based on the Index number returned by `RTM_GETADDR` to retrieve the network card's name, MTU, and flags.
Change-Id: Idf2fcd3cf88f1fc4d5c4a983717e1c601a63db74
GitHub-Last-Rev: 1012c07e4003e36475d32175a95c01821097a4bb
GitHub-Pull-Request: golang/go#61089
---
A src/net/interface_android.go
M src/net/interface_linux.go
M src/syscall/netlink_linux.go
3 files changed, 162 insertions(+), 1 deletion(-)
diff --git a/src/net/interface_android.go b/src/net/interface_android.go
new file mode 100644
index 0000000..cdae0fb
--- /dev/null
+++ b/src/net/interface_android.go
@@ -0,0 +1,152 @@
+// Copyright 2011 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.
+
+package net
+
+import (
+ "bytes"
+ "os"
+ "syscall"
+ "unsafe"
+)
+
+type ifReq [40]byte
+
+// Starting from Android 11, it is no longer possible to retrieve network card information
+// using the RTM_GETLINK method.
+// As a result, alternative methods need to be employed.
+// After considering the Android NetworkInterface.getNetworkInterfaces() method,
+// I opted to utilize the RTM_GETADDR + ioctl approach to obtain network card information.
+// However, it appears that retrieving the
+// HWAddr (hardware address) of the network card is currently not achievable.
+func interfaceTableAndroid(ifindex int) ([]Interface, error) {
+ tab, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
+ if err != nil {
+ return nil, os.NewSyscallError("netlinkrib", err)
+ }
+ msgs, err := syscall.ParseNetlinkMessage(tab)
+ if err != nil {
+ return nil, os.NewSyscallError("parsenetlinkmessage", err)
+ }
+
+ var ift []Interface
+ im := make(map[uint32]struct{})
+loop:
+ for _, m := range msgs {
+ switch m.Header.Type {
+ case syscall.NLMSG_DONE:
+ break loop
+ case syscall.RTM_NEWADDR:
+ ifam := (*syscall.IfAddrmsg)(unsafe.Pointer(&m.Data[0]))
+ if _, ok := im[ifam.Index]; ok {
+ continue
+ }
+
+ if ifindex == 0 || ifindex == int(ifam.Index) {
+ ifi := newLinkAndroid(ifam)
+ if ifi != nil {
+ ift = append(ift, *ifi)
+ }
+ if ifindex == int(ifam.Index) {
+ break loop
+ }
+ }
+ }
+ }
+
+ return ift, nil
+}
+
+// According to the network card Index, get the Name, MTU and Flags of the network card through ioctl
+func newLinkAndroid(ifam *syscall.IfAddrmsg) *Interface {
+ ift := &Interface{Index: int(ifam.Index)}
+
+ name, err := indexToName(ifam.Index)
+ if err != nil {
+ return nil
+ }
+ ift.Name = name
+
+ mtu, err := nameToMTU(name)
+ if err != nil {
+ return nil
+ }
+ ift.MTU = mtu
+
+ flags, err := nameToFlags(name)
+ if err != nil {
+ return nil
+ }
+ ift.Flags = flags
+ return ift
+}
+
+func ioctl(fd int, req uint, arg unsafe.Pointer) error {
+ _, _, e1 := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), uintptr(req), uintptr(arg))
+ if e1 != 0 {
+ return e1
+ }
+ return nil
+}
+
+func indexToName(index uint32) (string, error) {
+ fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM|syscall.SOCK_CLOEXEC, 0)
+ if err != nil {
+ return "", err
+ }
+ defer syscall.Close(fd)
+
+ var ifr ifReq
+ *(*uint32)(unsafe.Pointer(&ifr[syscall.IFNAMSIZ])) = index
+ err = ioctl(fd, syscall.SIOCGIFNAME, unsafe.Pointer(&ifr[0]))
+ if err != nil {
+ return "", err
+ }
+
+ return string(bytes.Trim(ifr[:syscall.IFNAMSIZ], "\x00")), nil
+}
+
+func nameToMTU(name string) (int, error) {
+ // Leave room for terminating NULL byte.
+ if len(name) >= syscall.IFNAMSIZ {
+ return 0, syscall.EINVAL
+ }
+
+ fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM|syscall.SOCK_CLOEXEC, 0)
+ if err != nil {
+ return 0, err
+ }
+ defer syscall.Close(fd)
+
+ var ifr ifReq
+ copy(ifr[:], name)
+ err = ioctl(fd, syscall.SIOCGIFMTU, unsafe.Pointer(&ifr[0]))
+ if err != nil {
+ return 0, err
+ }
+
+ return int(*(*int32)(unsafe.Pointer(&ifr[syscall.IFNAMSIZ]))), nil
+}
+
+func nameToFlags(name string) (Flags, error) {
+ // Leave room for terminating NULL byte.
+ if len(name) >= syscall.IFNAMSIZ {
+ return 0, syscall.EINVAL
+ }
+
+ fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM|syscall.SOCK_CLOEXEC, 0)
+ if err != nil {
+ return 0, err
+ }
+ defer syscall.Close(fd)
+
+ var ifr ifReq
+ copy(ifr[:], name)
+ err = ioctl(fd, syscall.SIOCGIFFLAGS, unsafe.Pointer(&ifr[0]))
+ if err != nil {
+ return 0, err
+ }
+
+ return linkFlags(*(*uint32)(unsafe.Pointer(&ifr[syscall.IFNAMSIZ]))), nil
+}
diff --git a/src/net/interface_linux.go b/src/net/interface_linux.go
index 9112ecc..c81bd0a 100644
--- a/src/net/interface_linux.go
+++ b/src/net/interface_linux.go
@@ -6,6 +6,7 @@
import (
"os"
+ "runtime"
"syscall"
"unsafe"
)
@@ -16,6 +17,9 @@
func interfaceTable(ifindex int) ([]Interface, error) {
tab, err := syscall.NetlinkRIB(syscall.RTM_GETLINK, syscall.AF_UNSPEC)
if err != nil {
+ if os.IsPermission(err) && runtime.GOOS == "android" {
+ return interfaceTableAndroid(ifindex)
+ }
return nil, os.NewSyscallError("netlinkrib", err)
}
msgs, err := syscall.ParseNetlinkMessage(tab)
diff --git a/src/syscall/netlink_linux.go b/src/syscall/netlink_linux.go
index a503a07..a74caa8 100644
--- a/src/syscall/netlink_linux.go
+++ b/src/syscall/netlink_linux.go
@@ -7,6 +7,8 @@
package syscall
import (
+ "os"
+ "runtime"
"sync"
"unsafe"
)
@@ -65,7 +67,10 @@
defer Close(s)
sa := &SockaddrNetlink{Family: AF_NETLINK}
if err := Bind(s, sa); err != nil {
- return nil, err
+ // Bind operation of Netlink socket is prohibited in Android11 and later versions
+ if !(runtime.GOOS == "android" && os.IsPermission(err)) {
+ return nil, err
+ }
}
wb := newNetlinkRouteRequest(proto, 1, family)
if err := Sendto(s, wb, 0, sa); err != nil {
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Gopher Robot (Gerrit)
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Gerrit Bot (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Ian Lance Taylor.
Gerrit Bot uploaded patch set #2 to this change.
x/mobile: fix net.Interface() and net.InterfaceAddrs() in Android11 version
For https://github.com/golang/go/issues/40569
Fix: In response to the modifications made to the permissions for accessing system MAC addresses in Android 11, ordinary applications encounter several main issues when using NETLINK sockets:
- Not allowing bind operations on `NETLINK` sockets.
- Not permitting the use of the `RTM_GETLINK` functionality.
For detailed information, please refer to: https://developer.android.com/training/articles/user-data-ids#mac-11-plus
As a result of the aforementioned reasons, using `net.Interfaces()` and `net.InterfaceAddrs()` from the Go net package in the Android environment leads to the `route ip+net: netlinkrib: permission denied` error.
You can find specific issue details here: https://github.com/golang/go/issues/40569
To address the issue of using the Go net package in the Android environment, we have made partial modifications to its source code to ensure proper functionality on Android.
I have fully resolved the issues with `net.InterfaceAddrs()`.
However, for `net.Interfaces()`, we have only addressed some problems, as the following issues still remain:
- It can only return interfaces with IP addresses.
- It cannot return hardware MAC addresses.
Nevertheless, the fixed `net.Interfaces()` function now aligns with the Android API's `NetworkInterface.getNetworkInterfaces()` and can be used normally in most scenarios.
The specific fix logic includes:
Removing the `Bind()` operation on `Netlink` sockets in the `NetlinkRIB()` function.
Using `ioctl` based on the Index number returned by `RTM_GETADDR` to retrieve the network card's name, MTU, and flags.
Change-Id: Idf2fcd3cf88f1fc4d5c4a983717e1c601a63db74
GitHub-Last-Rev: a64399c21a42214129aa3aaf7c28f42906b9ee5d
GitHub-Pull-Request: golang/go#61089
---
A src/net/interface_android.go
M src/net/interface_linux.go
M src/syscall/netlink_linux.go
3 files changed, 164 insertions(+), 1 deletion(-)
To view, visit change 507415. To unsubscribe, or for help writing mail filters, visit settings.
Gerrit Bot (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Ian Lance Taylor.
Gerrit Bot uploaded patch set #3 to this change.
x/mobile: fix net.Interface() and net.InterfaceAddrs() in Android11 version
For https://github.com/golang/go/issues/40569
Fix: In response to the modifications made to the permissions for accessing system MAC addresses in Android 11, ordinary applications encounter several main issues when using NETLINK sockets:
- Not allowing bind operations on `NETLINK` sockets.
- Not permitting the use of the `RTM_GETLINK` functionality.
For detailed information, please refer to: https://developer.android.com/training/articles/user-data-ids#mac-11-plus
As a result of the aforementioned reasons, using `net.Interfaces()` and `net.InterfaceAddrs()` from the Go net package in the Android environment leads to the `route ip+net: netlinkrib: permission denied` error.
You can find specific issue details here: https://github.com/golang/go/issues/40569
To address the issue of using the Go net package in the Android environment, we have made partial modifications to its source code to ensure proper functionality on Android.
I have fully resolved the issues with `net.InterfaceAddrs()`.
However, for `net.Interfaces()`, we have only addressed some problems, as the following issues still remain:
- It can only return interfaces with IP addresses.
- It cannot return hardware MAC addresses.
Nevertheless, the fixed `net.Interfaces()` function now aligns with the Android API's `NetworkInterface.getNetworkInterfaces()` and can be used normally in most scenarios.
The specific fix logic includes:
Removing the `Bind()` operation on `Netlink` sockets in the `NetlinkRIB()` function.
Using `ioctl` based on the Index number returned by `RTM_GETADDR` to retrieve the network card's name, MTU, and flags.
## Test Code
This part of the test code must be compiled into a jar and aar package that can be used under the Android 11 platform using gomobile
use `net.InterfaceAddrs()` :
```go
func NetInterfaceAddrs() {
addrs, err := net.InterfaceAddrs()
if err != nil {
panic(err)
}
for _, addr := range addrs {
log.Println(addr)
}
}
```
result:
```
127.0.0.1/8
::1/128
...
192.168.6.143/24
fe80::7e4f:4446:eb3:1eb8/64
```
use `net.Interfaces()` :
```go
func NetInterface() {
interfaces, err := net.Interfaces()
if err != nil {
panic(err)
}
for _, i := range interfaces {
log.Println(i)
}
}
```
result:
```
{1 65536 lo up|loopback|running}
{15 1400 rmnet_data1 up|running}
{24 1500 wlan0 up|broadcast|multicast|running}
{3 1500 dummy0 up|broadcast|running}
{4 1500 ifb0 up|broadcast|running}
{5 1500 ifb1 up|broadcast|running}
{12 1500 ifb2 up|broadcast|running}
{14 1500 rmnet_data0 up|running}
{16 1400 rmnet_data2 up|running}
{17 1400 rmnet_data3 up|running}
```
Change-Id: Idf2fcd3cf88f1fc4d5c4a983717e1c601a63db74
GitHub-Last-Rev: a64399c21a42214129aa3aaf7c28f42906b9ee5d
GitHub-Pull-Request: golang/go#61089
---
A src/net/interface_android.go
M src/net/interface_linux.go
M src/syscall/netlink_linux.go
3 files changed, 164 insertions(+), 1 deletion(-)
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wei liu (Gerrit)
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wei liu removed a vote from this change.
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wei liu (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Ian Lance Taylor.
Patch set 3:Code-Review +1
Zoltan Papp (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Hyang-Ah Hana Kim, Ian Lance Taylor.
1 comment:
File src/net/interface_linux.go:
Patch Set #3, Line 20:
if os.IsPermission(err) && runtime.GOOS == "android" {Maybe better if you put the if runtime.GOOS == "android" condition to the beginning of this function. With it you can avoid an unnecessary syscall on Android. Your approach fit better for the deprecated Android versions.
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Chih-Hsuan Yen (Gerrit)
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1 comment:
File src/net/interface_linux.go:
Patch Set #3, Line 20:
if os.IsPermission(err) && runtime.GOOS == "android" {
Maybe better if you put the if runtime. […]
Keeping RTM_GETLINK may be also useful for privileged Android applications (ex: those running as root).
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Gerrit Bot (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Hyang-Ah Hana Kim, Ian Lance Taylor, Zoltan Papp.
Gerrit Bot uploaded patch set #4 to this change.
GitHub-Last-Rev: ad4f8ff11f4fe68c5b06bf600ab683ef7f3fbec4
GitHub-Pull-Request: golang/go#61089
---
A src/net/interface_android.go
M src/net/interface_linux.go
M src/syscall/netlink_linux.go
3 files changed, 165 insertions(+), 1 deletion(-)
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GM K (Gerrit)
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1 comment:
File src/syscall/netlink_linux.go:
Patch Set #3, Line 71:
if !(runtime.GOOS == "android" && os.IsPermission(err)) {Including `os` package for this check here results in a cyclic dependency.
Removing the `os.IsPermission(err)` check would remove the need to import `os` package. This check was not done before this patch and any error of `Bind` resulted in an error returned for `NetlinRIB` so it won't change the behavior for the other platforms if removed
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Marcin Mazurek (Gerrit)
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1 comment:
Patchset:
The build is getting stuck at building bootstrap
mamazur@pc:~/go-source/src$ ./all.bash
Building Go cmd/dist using /snap/go/10389. (go1.21.3 linux/amd64)
Building Go toolchain1 using /snap/go/10389.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.It's been like that over 22 hours.
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Gerrit Bot (Gerrit)
Attention is currently required from: Brad Fitzpatrick, Damien Neil, Hyang-Ah Hana Kim, Ian Lance Taylor, Zoltan Papp.
Gerrit Bot uploaded patch set #5 to this change.
GitHub-Last-Rev: bff8d409ebfb8d4c8488325f13cb212b07cf6bb4
GitHub-Pull-Request: golang/go#61089
---
M src/net/interface_linux.go
M src/syscall/netlink_linux.go
2 files changed, 169 insertions(+), 2 deletions(-)
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