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package iptables
import (
"errors"
"net"
"syscall"
"github.com/sirupsen/logrus"
"github.com/vishvananda/netlink"
)
var (
// ErrConntrackNotConfigurable means that conntrack module is not loaded or does not have the netlink module loaded
ErrConntrackNotConfigurable = errors.New("conntrack is not available")
)
// IsConntrackProgrammable returns true if the handle supports the NETLINK_NETFILTER and the base modules are loaded
func IsConntrackProgrammable(nlh *netlink.Handle) bool {
return nlh.SupportsNetlinkFamily(syscall.NETLINK_NETFILTER)
}
// DeleteConntrackEntries deletes all the conntrack connections on the host for the specified IP
// Returns the number of flows deleted for IPv4, IPv6 else error
func DeleteConntrackEntries(nlh *netlink.Handle, ipv4List []net.IP, ipv6List []net.IP) (uint, uint, error) {
if !IsConntrackProgrammable(nlh) {
return 0, 0, ErrConntrackNotConfigurable
}
var totalIPv4FlowPurged uint
for _, ipAddress := range ipv4List {
flowPurged, err := purgeConntrackState(nlh, syscall.AF_INET, ipAddress)
if err != nil {
logrus.Warnf("Failed to delete conntrack state for %s: %v", ipAddress, err)
continue
}
totalIPv4FlowPurged += flowPurged
}
var totalIPv6FlowPurged uint
for _, ipAddress := range ipv6List {
flowPurged, err := purgeConntrackState(nlh, syscall.AF_INET6, ipAddress)
if err != nil {
logrus.Warnf("Failed to delete conntrack state for %s: %v", ipAddress, err)
continue
}
totalIPv6FlowPurged += flowPurged
}
logrus.Debugf("DeleteConntrackEntries purged ipv4:%d, ipv6:%d", totalIPv4FlowPurged, totalIPv6FlowPurged)
return totalIPv4FlowPurged, totalIPv6FlowPurged, nil
}
func purgeConntrackState(nlh *netlink.Handle, family netlink.InetFamily, ipAddress net.IP) (uint, error) {
filter := &netlink.ConntrackFilter{}
// NOTE: doing the flush using the ipAddress is safe because today there cannot be multiple networks with the same subnet
// so it will not be possible to flush flows that are of other containers
filter.AddIP(netlink.ConntrackNatAnyIP, ipAddress)
return nlh.ConntrackDeleteFilter(netlink.ConntrackTable, family, filter)
}
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