github.com/containerd/nerdctl@v1.7.7/pkg/containerinspector/containerinspector_linux.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package containerinspector
    18  
    19  import (
    20  	"context"
    21  	"fmt"
    22  	"net"
    23  	"strings"
    24  
    25  	"github.com/containerd/nerdctl/pkg/inspecttypes/native"
    26  
    27  	"github.com/containernetworking/plugins/pkg/ns"
    28  )
    29  
    30  func InspectNetNS(ctx context.Context, pid int) (*native.NetNS, error) {
    31  	nsPath := fmt.Sprintf("/proc/%d/ns/net", pid)
    32  	res := &native.NetNS{}
    33  	fn := func(_ ns.NetNS) error {
    34  		intf, err := net.Interfaces()
    35  		if err != nil {
    36  			return err
    37  		}
    38  		res.Interfaces = make([]native.NetInterface, len(intf))
    39  		for i, f := range intf {
    40  			x := native.NetInterface{
    41  				Interface: f,
    42  			}
    43  			if f.HardwareAddr != nil {
    44  				x.HardwareAddr = f.HardwareAddr.String()
    45  			}
    46  			if x.Interface.Flags.String() != "0" {
    47  				x.Flags = strings.Split(x.Interface.Flags.String(), "|")
    48  			}
    49  			if addrs, err := x.Interface.Addrs(); err == nil {
    50  				x.Addrs = make([]string, len(addrs))
    51  				for j, a := range addrs {
    52  					x.Addrs[j] = a.String()
    53  				}
    54  			}
    55  			res.Interfaces[i] = x
    56  		}
    57  		res.PrimaryInterface = determinePrimaryInterface(res.Interfaces)
    58  		return nil
    59  	}
    60  	if err := ns.WithNetNSPath(nsPath, fn); err != nil {
    61  		return nil, err
    62  	}
    63  	return res, nil
    64  }
    65  
    66  // determinePrimaryInterface returns a net.Interface.Index value, not a slice index.
    67  // Zero means no primary interface was detected.
    68  func determinePrimaryInterface(interfaces []native.NetInterface) int {
    69  	for _, f := range interfaces {
    70  		if f.Interface.Flags&net.FlagLoopback == 0 && f.Interface.Flags&net.FlagUp != 0 && !strings.HasPrefix(f.Name, "lo") {
    71  			return f.Index
    72  		}
    73  	}
    74  	return 0
    75  }