add support for ips in ipam config

plugin/ipam/cni.go

@@ -2,6 +2,7 @@ package ipamplugin
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net"
 
@@ -35,31 +36,80 @@ func (i *Ipam) Allocate(args *skel.CmdArgs) (types.Result, error) {
 	if containerID == "" {
 		return nil, fmt.Errorf("Weave CNI Allocate: blank container name")
 	}
-	var ipnet *net.IPNet
 
-	if conf.Subnet == "" {
-		ipnet, err = i.weave.AllocateIP(containerID, false)
+	var ipconfigs []*current.IPConfig
+
+	if len(conf.IPs) > 0 {
+		// configuration includes desired IPs
+
+		var ips []net.IP
+		for _, ip := range conf.IPs {
+			ip4 := net.ParseIP(ip).To4()
+			ip16 := net.ParseIP(ip).To16()
+
+			if ip4 == nil && ip16 == nil {
+				return nil, errors.New("provided value is not an IP")
+			}
+
+			if ip4 == nil && ip16 != nil {
+				return nil, errors.New("allocation of ipv6 addresses is not implemented")
+			}
+
+			ips = append(ips, ip4)
+		}
+
+		for j := range ips {
+			ipnet := &net.IPNet{
+				IP:   ips[j],
+				Mask: ips[j].DefaultMask(),
+			}
+
+			err := i.weave.ClaimIP(containerID, ipnet, false)
+			if err != nil {
+				return nil, err
+			}
+
+			ipconfigs = append(ipconfigs, &current.IPConfig{
+				Version: "4",
+				Address: *ipnet,
+				Gateway: conf.Gateway,
+			})
+		}
+	} else if conf.Subnet == "" {
+		// configuration doesn't include Subnet or IPs, so ask the allocator for an IP
+		ipnet, err := i.weave.AllocateIP(containerID, false)
+		if err != nil {
+			return nil, err
+		}
+
+		ipconfigs = append(ipconfigs, &current.IPConfig{
+			Version: "4",
+			Address: *ipnet,
+			Gateway: conf.Gateway,
+		})
 	} else {
-		var subnet *net.IPNet
-		subnet, err = types.ParseCIDR(conf.Subnet)
+		// configuration includes desired Subnet
+
+		subnet, err := types.ParseCIDR(conf.Subnet)
 		if err != nil {
 			return nil, fmt.Errorf("subnet given in config, but not parseable: %s", err)
 		}
-		ipnet, err = i.weave.AllocateIPInSubnet(containerID, subnet, false)
-	}
+		ipnet, err := i.weave.AllocateIPInSubnet(containerID, subnet, false)
+		if err != nil {
+			return nil, err
+		}
 
-	if err != nil {
-		return nil, err
-	}
-	result := &current.Result{
-		IPs: []*current.IPConfig{{
+		ipconfigs = append(ipconfigs, &current.IPConfig{
 			Version: "4",
 			Address: *ipnet,
 			Gateway: conf.Gateway,
-		}},
-		Routes: conf.Routes,
+		})
 	}
-	return result, nil
+
+	return &current.Result{
+		IPs:    ipconfigs,
+		Routes: conf.Routes,
+	}, nil
 }
 
 func (i *Ipam) CmdDel(args *skel.CmdArgs) error {
@@ -74,6 +124,7 @@ type ipamConf struct {
 	Subnet  string         `json:"subnet,omitempty"`
 	Gateway net.IP         `json:"gateway,omitempty"`
 	Routes  []*types.Route `json:"routes"`
+	IPs     []string       `json:"ips,omitempty"`
 }
 
 type netConf struct {

test/880_cni_plugin_ip_address_assignment_test.sh

@@ -0,0 +1,91 @@
+#! /bin/bash
+
+. "$(dirname "$0")/config.sh"
+
+start_suite "Test CNI plugin"
+
+cni_connect() {
+    pid=$(container_pid $1 $2)
+    id=$(docker_on $1 inspect -f '{{.Id}}' $2)
+    run_on $1 sudo CNI_COMMAND=ADD CNI_CONTAINERID=$id CNI_IFNAME=eth0 \
+    CNI_NETNS=/proc/$pid/ns/net CNI_PATH=/opt/cni/bin /opt/cni/bin/weave-net
+}
+
+run_on $HOST1 sudo mkdir -p /opt/cni/bin
+# setup-cni is a subset of 'weave setup', without doing any 'docker pull's
+weave_on $HOST1 setup-cni
+weave_on $HOST1 launch
+
+C0=$(docker_on $HOST1 run --net=none --name=c0 --privileged -dt $SMALL_IMAGE /bin/sh)
+C1=$(docker_on $HOST1 run --net=none --name=c1 --privileged -dt $SMALL_IMAGE /bin/sh)
+C2=$(docker_on $HOST1 run --net=none --name=c2 --privileged -dt $SMALL_IMAGE /bin/sh)
+
+# Enable unsolicited ARPs so that ping after the address reuse does not time out
+exec_on $HOST1 c1 sysctl -w net.ipv4.conf.all.arp_accept=1
+
+cni_connect $HOST1 c0 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net",
+    "ipam": {
+        "type": "weave-ipam",
+        "ips": [
+          "10.32.1.30"
+        ]
+    },
+    "hairpinMode": true
+}
+EOF
+
+cni_connect $HOST1 c1 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net",
+    "ipam": {
+        "type": "weave-ipam",
+        "ips": [
+          "10.32.1.40"
+        ]
+    },
+    "hairpinMode": true
+}
+EOF
+
+cni_connect $HOST1 c2 <<EOF
+{
+    "name": "weave",
+    "type": "weave-net",
+    "ipam": {
+        "type": "weave-ipam",
+        "ips": [
+          "10.32.1.42"
+        ]
+    },
+    "hairpinMode": true
+}
+EOF
+
+
+C0IP=$(container_ip $HOST1 c0)
+C1IP=$(container_ip $HOST1 c1)
+C2IP=$(container_ip $HOST1 c2)
+
+echo $C0IP
+echo $C1IP
+echo $C2IP
+
+# Ensure existing containers can reclaim their IP addresses after CNI has been used -- see #2548
+stop_weave_on $HOST1
+
+# Ensure no warning is printed to the standard error:
+ACTUAL_OUTPUT=$(CHECKPOINT_DISABLE="$CHECKPOINT_DISABLE" $WEAVE launch 2>&1)
+EXPECTED_OUTPUT=$(docker inspect --format="{{.Id}}" weave)
+
+assert_raises "[ $EXPECTED_OUTPUT == $ACTUAL_OUTPUT ]"
+
+assert "$SSH $HOST1 \"curl -s -X GET 127.0.0.1:6784/ip/$C1 | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'\"" "$C1IP"
+assert "$SSH $HOST1 \"curl -s -X GET 127.0.0.1:6784/ip/$C2 | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'\"" "$C2IP"
+assert "$SSH $HOST1 \"curl -s -X GET 127.0.0.1:6784/ip/$C3 | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'\"" "$C3IP"
+
+
+end_suite