github.com/jfrazelle/docker@v1.1.2-0.20210712172922-bf78e25fe508/libnetwork/iptables/conntrack.go (about)

     1  // +build linux
     2  
     3  package iptables
     4  
     5  import (
     6  	"errors"
     7  	"net"
     8  	"syscall"
     9  
    10  	"github.com/sirupsen/logrus"
    11  	"github.com/vishvananda/netlink"
    12  )
    13  
    14  var (
    15  	// ErrConntrackNotConfigurable means that conntrack module is not loaded or does not have the netlink module loaded
    16  	ErrConntrackNotConfigurable = errors.New("conntrack is not available")
    17  )
    18  
    19  // IsConntrackProgrammable returns true if the handle supports the NETLINK_NETFILTER and the base modules are loaded
    20  func IsConntrackProgrammable(nlh *netlink.Handle) bool {
    21  	return nlh.SupportsNetlinkFamily(syscall.NETLINK_NETFILTER)
    22  }
    23  
    24  // DeleteConntrackEntries deletes all the conntrack connections on the host for the specified IP
    25  // Returns the number of flows deleted for IPv4, IPv6 else error
    26  func DeleteConntrackEntries(nlh *netlink.Handle, ipv4List []net.IP, ipv6List []net.IP) (uint, uint, error) {
    27  	if !IsConntrackProgrammable(nlh) {
    28  		return 0, 0, ErrConntrackNotConfigurable
    29  	}
    30  
    31  	var totalIPv4FlowPurged uint
    32  	for _, ipAddress := range ipv4List {
    33  		flowPurged, err := purgeConntrackState(nlh, syscall.AF_INET, ipAddress)
    34  		if err != nil {
    35  			logrus.Warnf("Failed to delete conntrack state for %s: %v", ipAddress, err)
    36  			continue
    37  		}
    38  		totalIPv4FlowPurged += flowPurged
    39  	}
    40  
    41  	var totalIPv6FlowPurged uint
    42  	for _, ipAddress := range ipv6List {
    43  		flowPurged, err := purgeConntrackState(nlh, syscall.AF_INET6, ipAddress)
    44  		if err != nil {
    45  			logrus.Warnf("Failed to delete conntrack state for %s: %v", ipAddress, err)
    46  			continue
    47  		}
    48  		totalIPv6FlowPurged += flowPurged
    49  	}
    50  
    51  	logrus.Debugf("DeleteConntrackEntries purged ipv4:%d, ipv6:%d", totalIPv4FlowPurged, totalIPv6FlowPurged)
    52  	return totalIPv4FlowPurged, totalIPv6FlowPurged, nil
    53  }
    54  
    55  func purgeConntrackState(nlh *netlink.Handle, family netlink.InetFamily, ipAddress net.IP) (uint, error) {
    56  	filter := &netlink.ConntrackFilter{}
    57  	// NOTE: doing the flush using the ipAddress is safe because today there cannot be multiple networks with the same subnet
    58  	// so it will not be possible to flush flows that are of other containers
    59  	if err := filter.AddIP(netlink.ConntrackNatAnyIP, ipAddress); err != nil {
    60  		return 0, err
    61  	}
    62  	return nlh.ConntrackDeleteFilter(netlink.ConntrackTable, family, filter)
    63  }