cmd/scion: add json/yaml format to ping and traceroute

private/path/pathpol/sequence.go

@@ -83,33 +83,14 @@ func (s *Sequence) Eval(paths []snet.Path) []snet.Path {
 	}
 	result := []snet.Path{}
 	for _, path := range paths {
-		var desc string
-		ifaces := path.Metadata().Interfaces
-		switch {
-		// Path should contain even number of interfaces. 1 for source AS,
-		// 1 for destination AS and 2 per each intermediate AS. Invalid paths should
-		// not occur but if they do let's ignore them.
-		case len(ifaces)%2 != 0:
-			log.Error("Invalid path with even number of hops", "path", path)
+		desc, err := GetSequence(path)
+		if desc != "" {
+			desc = desc + " "
+		}
+		if err != nil {
+			log.Error("get sequence from path", "err", err)
 			continue
-		// Empty paths are special cased.
-		case len(ifaces) == 0:
-			desc = ""
-		default:
-			// Turn the path into a string. For each AS on the path there will be
-			// one element in form <IA>#<inbound-interface>,<outbound-interface>,
-			// e.g. 64-ff00:0:112#3,5. For the source AS, the inbound interface will be
-			// zero. For destination AS, outbound interface will be zero.
-
-			hops := make([]string, 0, len(ifaces)/2+1)
-			hops = append(hops, hop(ifaces[0].IA, 0, ifaces[0].ID))
-			for i := 1; i < len(ifaces)-1; i += 2 {
-				hops = append(hops, hop(ifaces[i].IA, ifaces[i].ID, ifaces[i+1].ID))
-			}
-			hops = append(hops, hop(ifaces[len(ifaces)-1].IA, ifaces[len(ifaces)-1].ID, 0))
-			desc = strings.Join(hops, " ") + " "
 		}
-
 		// Check whether the string matches the sequence regexp.
 		if s.re.MatchString(desc) {
 			result = append(result, path)
@@ -315,3 +296,36 @@ func (l *sequenceListener) ExitIFace(c *sequence.IFaceContext) {
 func hop(ia addr.IA, ingress, egress common.IFIDType) string {
 	return fmt.Sprintf("%s#%d,%d", ia, ingress, egress)
 }
+
+// GetSequence constructs the sequence string from snet path
+// output format:
+//
+//	1-ff00:0:133#42 1-ff00:0:120#2,1 1-ff00:0:110#21
+func GetSequence(path snet.Path) (string, error) {
+	var desc string
+	ifaces := path.Metadata().Interfaces
+	switch {
+	// Path should contain even number of interfaces. 1 for source AS,
+	// 1 for destination AS and 2 per each intermediate AS. Invalid paths should
+	// not occur but if they do let's ignore them.
+	case len(ifaces)%2 != 0:
+		return "", serrors.New("Invalid path with odd number of hops", "path", path)
+	// Empty paths are special cased.
+	case len(ifaces) == 0:
+		desc = ""
+	default:
+		// Turn the path into a string. For each AS on the path there will be
+		// one element in form <IA>#<inbound-interface>,<outbound-interface>,
+		// e.g. 64-ff00:0:112#3,5. For the source AS, the inbound interface will be
+		// zero. For destination AS, outbound interface will be zero.
+
+		hops := make([]string, 0, len(ifaces)/2+1)
+		hops = append(hops, hop(ifaces[0].IA, 0, ifaces[0].ID))
+		for i := 1; i < len(ifaces)-1; i += 2 {
+			hops = append(hops, hop(ifaces[i].IA, ifaces[i].ID, ifaces[i+1].ID))
+		}
+		hops = append(hops, hop(ifaces[len(ifaces)-1].IA, ifaces[len(ifaces)-1].ID, 0))
+		desc = strings.Join(hops, " ")
+	}
+	return desc, nil
+}

scion/cmd/scion/BUILD.bazel

@@ -5,6 +5,7 @@ go_library(
     name = "go_default_library",
     srcs = [
         "address.go",
+        "common.go",
         "gendocs.go",
         "main.go",
         "observability.go",
@@ -18,6 +19,7 @@ go_library(
         "//pkg/addr:go_default_library",
         "//pkg/daemon:go_default_library",
         "//pkg/log:go_default_library",
+        "//pkg/private/common:go_default_library",
         "//pkg/private/serrors:go_default_library",
         "//pkg/snet:go_default_library",
         "//pkg/snet/addrutil:go_default_library",
@@ -28,6 +30,7 @@ go_library(
         "//private/app/flag:go_default_library",
         "//private/app/path:go_default_library",
         "//private/env:go_default_library",
+        "//private/path/pathpol:go_default_library",
         "//private/topology:go_default_library",
         "//private/tracing:go_default_library",
         "//scion/ping:go_default_library",
@@ -36,6 +39,7 @@ go_library(
         "@com_github_opentracing_opentracing_go//:go_default_library",
         "@com_github_spf13_cobra//:go_default_library",
         "@com_github_spf13_cobra//doc:go_default_library",
+        "@in_gopkg_yaml_v2//:go_default_library",
     ],
 )
 

scion/cmd/scion/common.go

@@ -0,0 +1,74 @@
+// Copyright 2022 Anapaya Systems
+//
+// 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
+
+import (
+	"fmt"
+	"io"
+	"net"
+
+	"github.com/scionproto/scion/pkg/addr"
+	"github.com/scionproto/scion/pkg/private/common"
+	"github.com/scionproto/scion/pkg/private/serrors"
+	"github.com/scionproto/scion/pkg/snet"
+)
+
+// Path defines the base model for the `ping` and `traceroute` result path
+type Path struct {
+	// Hex-string representing the paths fingerprint.
+	Fingerprint string `json:"fingerprint" yaml:"fingerprint"`
+	Hops        []Hop  `json:"hops" yaml:"hops"`
+	Sequence    string `json:"sequence" yaml:"sequence"`
+
+	LocalIP net.IP `json:"local_ip,omitempty" yaml:"local_ip,omitempty"`
+
+	// The internal UDP/IP underlay address of the SCION router that forwards traffic for this path.
+	NextHop string `json:"next_hop" yaml:"next_hop"`
+}
+
+// Hop represents an hop on the path.
+type Hop struct {
+	ID common.IFIDType `json:"interface" yaml:"interface"`
+	IA addr.IA         `json:"isd_as" yaml:"isd_as"`
+}
+
+// getHops constructs a list of snet path interfaces from an snet path
+func getHops(path snet.Path) []Hop {
+	ifaces := path.Metadata().Interfaces
+	var hops []Hop
+	if len(ifaces) == 0 {
+		return hops
+	}
+	for i := range ifaces {
+		intf := ifaces[i]
+		hops = append(hops, Hop{IA: intf.IA, ID: intf.ID})
+	}
+	return hops
+}
+
+// getPrintf returns a printf function for the "human" formatting flag and an empty one for machine
+// readable format flags
+func getPrintf(output string, writer io.Writer) (func(format string, ctx ...interface{}), error) {
+	switch output {
+	case "human":
+		return func(format string, ctx ...interface{}) {
+			fmt.Fprintf(writer, format, ctx...)
+		}, nil
+	case "yaml", "json":
+		return func(format string, ctx ...interface{}) {}, nil
+	default:
+		return nil, serrors.New("format not supported", "format", output)
+	}
+}