github.com/zhuohuang-hust/src-cbuild@v0.0.0-20230105071821-c7aab3e7c840/mergeCode/libnetwork/ns/init_linux.go (about)

     1  package ns
     2  
     3  import (
     4  	"fmt"
     5  	"os"
     6  	"os/exec"
     7  	"strings"
     8  	"sync"
     9  	"syscall"
    10  
    11  	log "github.com/Sirupsen/logrus"
    12  	"github.com/vishvananda/netlink"
    13  	"github.com/vishvananda/netns"
    14  )
    15  
    16  var (
    17  	initNs   netns.NsHandle
    18  	initNl   *netlink.Handle
    19  	initOnce sync.Once
    20  )
    21  
    22  // Init initializes a new network namespace
    23  func Init() {
    24  	var err error
    25  	initNs, err = netns.Get()
    26  	if err != nil {
    27  		log.Errorf("could not get initial namespace: %v", err)
    28  	}
    29  	initNl, err = netlink.NewHandle(getSupportedNlFamilies()...)
    30  	if err != nil {
    31  		log.Errorf("could not create netlink handle on initial namespace: %v", err)
    32  	}
    33  }
    34  
    35  // SetNamespace sets the initial namespace handler
    36  func SetNamespace() error {
    37  	initOnce.Do(Init)
    38  	if err := netns.Set(initNs); err != nil {
    39  		linkInfo, linkErr := getLink()
    40  		if linkErr != nil {
    41  			linkInfo = linkErr.Error()
    42  		}
    43  		return fmt.Errorf("failed to set to initial namespace, %v, initns fd %d: %v", linkInfo, initNs, err)
    44  	}
    45  	return nil
    46  }
    47  
    48  // ParseHandlerInt transforms the namespace handler into an integer
    49  func ParseHandlerInt() int {
    50  	return int(getHandler())
    51  }
    52  
    53  // GetHandler returns the namespace handler
    54  func getHandler() netns.NsHandle {
    55  	initOnce.Do(Init)
    56  	return initNs
    57  }
    58  
    59  func getLink() (string, error) {
    60  	return os.Readlink(fmt.Sprintf("/proc/%d/task/%d/ns/net", os.Getpid(), syscall.Gettid()))
    61  }
    62  
    63  // NlHandle returns the netlink handler
    64  func NlHandle() *netlink.Handle {
    65  	initOnce.Do(Init)
    66  	return initNl
    67  }
    68  
    69  func getSupportedNlFamilies() []int {
    70  	fams := []int{syscall.NETLINK_ROUTE}
    71  	if err := loadXfrmModules(); err != nil {
    72  		if checkXfrmSocket() != nil {
    73  			log.Warnf("Could not load necessary modules for IPSEC rules: %v", err)
    74  			return fams
    75  		}
    76  	}
    77  	return append(fams, syscall.NETLINK_XFRM)
    78  }
    79  
    80  func loadXfrmModules() error {
    81  	if out, err := exec.Command("modprobe", "-va", "xfrm_user").CombinedOutput(); err != nil {
    82  		return fmt.Errorf("Running modprobe xfrm_user failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
    83  	}
    84  	if out, err := exec.Command("modprobe", "-va", "xfrm_algo").CombinedOutput(); err != nil {
    85  		return fmt.Errorf("Running modprobe xfrm_algo failed with message: `%s`, error: %v", strings.TrimSpace(string(out)), err)
    86  	}
    87  	return nil
    88  }
    89  
    90  // API check on required xfrm modules (xfrm_user, xfrm_algo)
    91  func checkXfrmSocket() error {
    92  	fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW, syscall.NETLINK_XFRM)
    93  	if err != nil {
    94  		return err
    95  	}
    96  	syscall.Close(fd)
    97  	return nil
    98  }