bpf: Migrate cilium-migrate-map From C to Go

Currently initializing bpf programs and migrating maps
is done with a bash script. This creates a Go version of
the "cilium-migrate-map" program and refactors it to be
useful by a, similarly, migrated init program. Specifically,
giving feedback as to whether any maps even need migrating
(often they don't) thus allowing the init program to
skip the expensive loading and processing of ELF files.

Additionally, a Go version of the C command line program
is also added to the cilium container cli program to be used,
temporarily, by the init.sh program to ensure that the logic
of the new Go migrate program is sound.

Signed-off-by: Nate Sweet <nathanjsweet@pm.me>

bpf/init.sh

@@ -260,12 +260,12 @@ function bpf_load()
 	bpf_compile $IN $OUT obj "$OPTS"
 	tc qdisc replace dev $DEV clsact || true
 	[ -z "$(tc filter show dev $DEV $WHERE | grep -v 'pref 1 bpf chain 0 $\|pref 1 bpf chain 0 handle 0x1')" ] || tc filter del dev $DEV $WHERE
-	cilium-map-migrate -s $OUT
+        cilium map migrate -s $OUT
 	set +e
 	tc filter replace dev $DEV $WHERE prio 1 handle 1 bpf da obj $OUT sec $SEC
 	RETCODE=$?
 	set -e
-	cilium-map-migrate -e $OUT -r $RETCODE
+	cilium map migrate -e $OUT -r $RETCODE
 	return $RETCODE
 }
 
@@ -286,12 +286,12 @@ function bpf_load_cgroups()
 	TMP_FILE="$BPFMNT/tc/globals/cilium_cgroups_$WHERE"
 	rm -f $TMP_FILE
 
-	cilium-map-migrate -s $OUT
+	cilium map migrate -s $OUT
 	set +e
 	tc exec bpf pin $TMP_FILE obj $OUT type $PROG_TYPE attach_type $WHERE sec $WHERE
 	RETCODE=$?
 	set -e
-	cilium-map-migrate -e $OUT -r $RETCODE
+	cilium map migrate -e $OUT -r $RETCODE
 
 	if [ "$RETCODE" -eq "0" ]; then
 		set +e

cilium/cmd/bpf_map.go

@@ -0,0 +1,29 @@
+// Copyright 2021 Authors of Cilium
+//
+// 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 cmd
+
+import (
+	"github.com/spf13/cobra"
+)
+
+// bpfMigrateCmd represents the map command
+var bpfMapCmd = &cobra.Command{
+	Use:   "map",
+	Short: "BPF map commands",
+}
+
+func init() {
+	bpfCmd.AddCommand(bpfMapCmd)
+}

cilium/cmd/bpf_map_migrate.go

@@ -0,0 +1,73 @@
+// Copyright 2021 Authors of Cilium
+//
+// 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 cmd
+
+import (
+	"log/syslog"
+
+	"github.com/spf13/cobra"
+
+	"github.com/cilium/cilium/pkg/bpf/migrate"
+)
+
+// bpfMigrateCmd represents the migrate command
+var (
+	bpfMigrateCmd = &cobra.Command{
+		Use:   "migrate",
+		Short: "Migrate map",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(s) > 0 && len(e) > 0 {
+				log.Fatalf("s (%q) and e (%q) cannot be both set", s, e)
+			}
+			var (
+				pathName string
+				finalize bool
+			)
+			if len(s) > 0 {
+				pathName = s
+			} else if len(e) > 0 {
+				pathName = e
+				finalize = true
+			} else {
+				log.Fatalf("either s or e must be a valid filepath")
+			}
+			sysLogger, err := syslog.New(syslog.LOG_WARNING, "cilium-map-migrate")
+			if err != nil {
+				log.Printf("Could not open syslog: %v", err)
+				sysLogger = nil
+			} else {
+				defer sysLogger.Close()
+			}
+			if !finalize {
+				_, err = migrate.Start(pathName, sysLogger)
+			} else {
+				err = migrate.Finish(pathName, r, sysLogger)
+			}
+			if err != nil {
+				log.Fatalf("error migrating state for %q: %v", pathName, err)
+			}
+		},
+	}
+	s string
+	e string
+	r int
+)
+
+func init() {
+	bpfMapCmd.AddCommand(bpfMigrateCmd)
+	bpfMigrateCmd.Flags().StringVarP(&s, "start", "s", "", "start file")
+	bpfMigrateCmd.Flags().StringVarP(&e, "end", "e", "", "end file")
+	bpfMigrateCmd.Flags().IntVarP(&r, "return", "r", 0, "return code")
+}

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/blang/semver/v4 v4.0.0
 	github.com/cilium/customvet v0.0.0-20201209211516-9852765c1ac4
 	github.com/cilium/deepequal-gen v0.0.0-20200406125435-ad6a9003139e
-	github.com/cilium/ebpf v0.5.1-0.20210421150058-a4ee356536f3
+	github.com/cilium/ebpf v0.6.3-0.20210804143410-d3bc4435231e
 	github.com/cilium/ipam v0.0.0-20201106170308-4184bc4bf9d6
 	github.com/cilium/proxy v0.0.0-20210511221533-82a70d56bf32
 	github.com/cncf/udpa/go v0.0.0-20201211205326-cc1b757b3edd // indirect