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Merge pull request #61 from plumgrid/arping
Arping capabilities for CNM
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,159 @@ | ||
| // Copyright 2016 PLUMgrid | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License.package main | ||
|
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| package driver | ||
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| import ( | ||
| "fmt" | ||
| "net" | ||
| "strings" | ||
| "time" | ||
|
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| "github.com/google/gopacket" | ||
| "github.com/google/gopacket/layers" | ||
| "github.com/google/gopacket/pcap" | ||
|
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| Log "github.com/Sirupsen/logrus" | ||
| "github.com/eduser25/cni/pkg/ns" | ||
| ) | ||
|
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| // Plumgrid just specifies the prefix, so we will arping on all ifcs | ||
| // that match with the prefix given to libnetwork | ||
| func RunContainerArping(net_ns_path string, pg_ifc_prefix string) error { | ||
|
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| Log.Printf("Attempting to acces the container %s NetNS", net_ns_path) | ||
| var netns ns.NetNS | ||
| var err error | ||
| success := false | ||
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| for attempts := 0; attempts <= 5; attempts++ { | ||
|
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| netns, err = ns.GetNS(net_ns_path) | ||
|
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| if err != nil { | ||
| Log.Printf("Attempt %d: failed to open netns %s: %v", attempts, net_ns_path, err) | ||
| time.Sleep(1 * time.Second) | ||
| } else { | ||
| success = true | ||
| break | ||
| } | ||
| attempts += 1 | ||
| } | ||
|
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||
| if !success { | ||
| return fmt.Errorf("Attempts exhaused, could not access %s, exiting", net_ns_path) | ||
| } | ||
| defer netns.Close() | ||
|
|
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| // Let's go in | ||
| err = netns.Do(func(_ ns.NetNS) error { | ||
|
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| // Get Ifcs on container | ||
| ifc_list, err := net.Interfaces() | ||
| if err != nil { | ||
| return fmt.Errorf("Failed to get interfaces in Netns: %v", err) | ||
| } | ||
|
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| // Iterate Ifcs | ||
| for _, ifc := range ifc_list { | ||
| if strings.HasPrefix(ifc.Name, pg_ifc_prefix) { | ||
| // Valid PG-created ifc | ||
|
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||
| // TODO we might want to add a retry here to make sure, | ||
| // in case the IFC is up but still has no IP, we retry | ||
| address_slice, err := ifc.Addrs() | ||
| if err != nil { | ||
| Log.Errorf("Failed to get Address slice for ifc %s: %v", ifc.Name, err) | ||
| continue | ||
| } | ||
|
|
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| if len(address_slice) == 0 { | ||
| Log.Errorf("Interface %s had no IP address at the moment we checked", ifc.Name) | ||
| continue | ||
| } | ||
|
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| Log.Printf("Attempting raw socket open on %s", ifc.Name) | ||
| handle, err := pcap.OpenLive(ifc.Name, 65536, true, pcap.BlockForever) | ||
| if err != nil { | ||
| return fmt.Errorf("Failed to open raw socket %s : %v", ifc.Name, err) | ||
| } | ||
|
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| // We will just arping for all IPv4 addresses on this ifc, just in case | ||
| for _, ifc_addr := range address_slice { | ||
| ip, _, err := net.ParseCIDR(ifc_addr.String()) | ||
| if err != nil { | ||
| Log.Printf("Failed to parse network %s : %v", ifc_addr.String(), err) | ||
| continue | ||
| } | ||
|
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| if ip.To4() == nil { | ||
| // ignoring IPV6 addr | ||
| continue | ||
| } | ||
|
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| // Get ARP packet | ||
| arp_pkt := getGratuitousArp(ifc.HardwareAddr, ip) | ||
|
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| for i := 0; i <= 3; i++ { | ||
| Log.Printf("Sending %d GARP on %s : %s - %s", | ||
| i, ifc.Name, ifc.HardwareAddr.String(), ip.String()) | ||
|
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| if err := handle.WritePacketData(arp_pkt); err != nil { | ||
| handle.Close() | ||
| return fmt.Errorf("Failed to write ARP packet data on %s : %v", ifc.Name, err) | ||
| } | ||
| time.Sleep(750 * time.Millisecond) | ||
| } | ||
| } | ||
|
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| // Close the socket | ||
| handle.Close() | ||
| } | ||
| } | ||
| return nil | ||
| }) | ||
|
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| return err | ||
| } | ||
|
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| func getGratuitousArp(mac net.HardwareAddr, ip net.IP) []byte { | ||
| // Set up all the layers' fields we can. | ||
| eth := layers.Ethernet{ | ||
| SrcMAC: mac, | ||
| DstMAC: net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, | ||
| EthernetType: layers.EthernetTypeARP, | ||
| } | ||
| arp := layers.ARP{ | ||
| AddrType: layers.LinkTypeEthernet, | ||
| Protocol: layers.EthernetTypeIPv4, | ||
| HwAddressSize: 6, | ||
| ProtAddressSize: 4, | ||
| Operation: layers.ARPReply, | ||
| SourceHwAddress: mac, | ||
| SourceProtAddress: ip.To4(), | ||
| DstHwAddress: []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, | ||
| DstProtAddress: ip.To4(), | ||
| } | ||
| // Set up buffer and options for serialization. | ||
| buf := gopacket.NewSerializeBuffer() | ||
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| opts := gopacket.SerializeOptions{ | ||
| FixLengths: true, | ||
| ComputeChecksums: true, | ||
| } | ||
| // Send one packet for every address. | ||
| gopacket.SerializeLayers(buf, opts, ð, &arp) | ||
|
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| return buf.Bytes() | ||
| } |