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Segment clean up
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Tilmann Zäschke committed Feb 28, 2024
1 parent 62ecc6b commit 5b11f83
Showing 1 changed file with 140 additions and 140 deletions.
280 changes: 140 additions & 140 deletions src/main/java/org/scion/internal/Segments.java
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,146 @@ public class Segments {

private Segments() {}

public static List<Daemon.Path> getPaths(
SegmentLookupServiceGrpc.SegmentLookupServiceBlockingStub segmentStub,
ScionBootstrapper brLookup,
long srcIsdAs,
long dstIsdAs) {
// Cases:
// A: src==dst
// B: srcISD==dstISD; dst==core
// C: srcISD==dstISD; src==core
// D: srcISD==dstISD; src==core, dst==core
// E: srcISD==dstISD;
// F: srcISD!=dstISD; dst==core
// G: srcISD!=dstISD; src==core
// H: srcISD!=dstISD;
long srcWildcard = toWildcard(srcIsdAs);
long dstWildcard = toWildcard(dstIsdAs);
int srcISD = ScionUtil.extractIsd(srcIsdAs);
int dstISD = ScionUtil.extractIsd(dstIsdAs);

if (srcIsdAs == dstIsdAs) {
// case A: same AS, return empty path
Daemon.Path.Builder path = Daemon.Path.newBuilder();
path.setMtu(brLookup.getLocalMtu());
path.setExpiration(Timestamp.newBuilder().setSeconds(Instant.now().getEpochSecond()).build());
return Collections.singletonList(path.build());
}

// TODO in future we can find out whether an AS is CORE by parsing the TRC files:
// https://docs.anapaya.net/en/latest/resources/isd-as-assignments/#as-assignments
// ./bazel-bin/scion-pki/cmd/scion-pki/scion-pki_/scion-pki trc inspect
// ../../Downloads/ISD64.bundle

long from = srcIsdAs;
long to = dstIsdAs;
List<List<Seg.PathSegment>> segments = new ArrayList<>();
if (!brLookup.isLocalAsCore()) {
// get UP segments
// TODO find out if dstIsAs is core and directly ask for it.
List<Seg.PathSegment> segmentsUp = getSegments(segmentStub, srcIsdAs, srcWildcard);
boolean[] containsIsdAs = containsIsdAs(segmentsUp, srcIsdAs, dstIsdAs);
if (containsIsdAs[1]) {
// case B: DST is core
return combineSegment(segmentsUp, brLookup);
}
segments.add(segmentsUp);
from = srcWildcard;
}

if (srcISD == dstISD) {
// cases C, D, E
// TODO this is an expensive way to find out whether DST is CORE
List<Seg.PathSegment> segmentsCoreOrDown = getSegments(segmentStub, from, dstIsdAs);
if (!segmentsCoreOrDown.isEmpty()) {
// Okay, we found a direct route from src(Wildcard) to DST
segments.add(segmentsCoreOrDown);
List<Daemon.Path> paths = combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
if (!paths.isEmpty()) {
return paths;
}
// okay, we need CORE!
// TODO this is horrible.
segments.remove(segments.size() - 1);
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
segments.add(segmentsCore);
segments.add(segmentsCoreOrDown);
return combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}
// Try again with wildcard (DST is neither core nor a child of FROM)
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
boolean[] coreHasIA = containsIsdAs(segmentsCore, from, dstIsdAs);
segments.add(segmentsCore);
if (coreHasIA[1]) {
// case D: DST is core
// TODO why is this ever used? See e.g. Test F0 111->120
return combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);

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} else {
from = dstWildcard;
// case C: DST is not core
// We have to query down segments because SRC may not have a segment connected to DST
List<Seg.PathSegment> segmentsDown = getSegments(segmentStub, from, dstIsdAs);
segments.add(segmentsDown);
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}
}
// remaining cases: F, G, H
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
boolean[] localCores = Segments.containsIsdAs(segmentsCore, srcIsdAs, dstIsdAs);
segments.add(segmentsCore);
if (localCores[1]) {
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}

List<Seg.PathSegment> segmentsDown = getSegments(segmentStub, dstWildcard, dstIsdAs);
segments.add(segmentsDown);
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}

private static List<Seg.PathSegment> getSegments(
SegmentLookupServiceGrpc.SegmentLookupServiceBlockingStub segmentStub,
long srcIsdAs,
long dstIsdAs) {
if (LOG.isInfoEnabled()) {
LOG.info(

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"Requesting segments: {} {}",
ScionUtil.toStringIA(srcIsdAs),
ScionUtil.toStringIA(dstIsdAs));

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}
Seg.SegmentsRequest request =
Seg.SegmentsRequest.newBuilder().setSrcIsdAs(srcIsdAs).setDstIsdAs(dstIsdAs).build();
try {
Seg.SegmentsResponse response = segmentStub.segments(request);
if (response.getSegmentsMap().size() > 1) {
// TODO fix! We need to be able to handle more than one segment collection (?)
throw new UnsupportedOperationException();

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}
return getPathSegments(response);
} catch (StatusRuntimeException e) {

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if (e.getStatus().getCode().equals(Status.Code.UNKNOWN)
&& e.getMessage().contains("TRC not found")) {
String msg = ScionUtil.toStringIA(srcIsdAs) + " / " + ScionUtil.toStringIA(dstIsdAs);
throw new ScionRuntimeException(

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"Error while getting Segments: unknown src/dst ISD-AS: " + msg, e);
}
if (e.getStatus().getCode().equals(Status.Code.UNAVAILABLE)) {
throw new ScionRuntimeException(

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"Error while getting Segments: cannot connect to SCION network", e);
}
throw new ScionRuntimeException("Error while getting Segment info: " + e.getMessage(), e);

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}
}

private static List<Seg.PathSegment> getPathSegments(Seg.SegmentsResponse response) {
List<Seg.PathSegment> pathSegments = new ArrayList<>();
for (Map.Entry<Integer, Seg.SegmentsResponse.Segments> seg :
response.getSegmentsMap().entrySet()) {
pathSegments.addAll(seg.getValue().getSegmentsList());
}
return pathSegments;
}

private static List<Daemon.Path> combineSegments(
List<List<Seg.PathSegment>> segments,
long srcIsdAs,
Expand Down Expand Up @@ -353,146 +493,6 @@ private static boolean[] containsIsdAs(
return found;
}

private static List<Seg.PathSegment> getSegments(
SegmentLookupServiceGrpc.SegmentLookupServiceBlockingStub segmentStub,
long srcIsdAs,
long dstIsdAs) {
if (LOG.isInfoEnabled()) {
LOG.info(
"Requesting segments: {} {}",
ScionUtil.toStringIA(srcIsdAs),
ScionUtil.toStringIA(dstIsdAs));
}
Seg.SegmentsRequest request =
Seg.SegmentsRequest.newBuilder().setSrcIsdAs(srcIsdAs).setDstIsdAs(dstIsdAs).build();
try {
Seg.SegmentsResponse response = segmentStub.segments(request);
if (response.getSegmentsMap().size() > 1) {
// TODO fix! We need to be able to handle more than one segment collection (?)
throw new UnsupportedOperationException();
}
return getPathSegments(response);
} catch (StatusRuntimeException e) {
if (e.getStatus().getCode().equals(Status.Code.UNKNOWN)
&& e.getMessage().contains("TRC not found")) {
String msg = ScionUtil.toStringIA(srcIsdAs) + " / " + ScionUtil.toStringIA(dstIsdAs);
throw new ScionRuntimeException(
"Error while getting Segments: unknown src/dst ISD-AS: " + msg, e);
}
if (e.getStatus().getCode().equals(Status.Code.UNAVAILABLE)) {
throw new ScionRuntimeException(
"Error while getting Segments: cannot connect to SCION network", e);
}
throw new ScionRuntimeException("Error while getting Segment info: " + e.getMessage(), e);
}
}

private static List<Seg.PathSegment> getPathSegments(Seg.SegmentsResponse response) {
List<Seg.PathSegment> pathSegments = new ArrayList<>();
for (Map.Entry<Integer, Seg.SegmentsResponse.Segments> seg :
response.getSegmentsMap().entrySet()) {
pathSegments.addAll(seg.getValue().getSegmentsList());
}
return pathSegments;
}

public static List<Daemon.Path> getPaths(
SegmentLookupServiceGrpc.SegmentLookupServiceBlockingStub segmentStub,
ScionBootstrapper brLookup,
long srcIsdAs,
long dstIsdAs) {
// Cases:
// A: src==dst
// B: srcISD==dstISD; dst==core
// C: srcISD==dstISD; src==core
// D: srcISD==dstISD; src==core, dst==core
// E: srcISD==dstISD;
// F: srcISD!=dstISD; dst==core
// G: srcISD!=dstISD; src==core
// H: srcISD!=dstISD;
long srcWildcard = toWildcard(srcIsdAs);
long dstWildcard = toWildcard(dstIsdAs);
int srcISD = ScionUtil.extractIsd(srcIsdAs);
int dstISD = ScionUtil.extractIsd(dstIsdAs);

if (srcIsdAs == dstIsdAs) {
// case A: same AS, return empty path
Daemon.Path.Builder path = Daemon.Path.newBuilder();
path.setMtu(brLookup.getLocalMtu());
path.setExpiration(Timestamp.newBuilder().setSeconds(Instant.now().getEpochSecond()).build());
return Collections.singletonList(path.build());
}

// TODO in future we can find out whether an AS is CORE by parsing the TRC files:
// https://docs.anapaya.net/en/latest/resources/isd-as-assignments/#as-assignments
// ./bazel-bin/scion-pki/cmd/scion-pki/scion-pki_/scion-pki trc inspect
// ../../Downloads/ISD64.bundle

long from = srcIsdAs;
long to = dstIsdAs;
List<List<Seg.PathSegment>> segments = new ArrayList<>();
if (!brLookup.isLocalAsCore()) {
// get UP segments
// TODO find out if dstIsAs is core and directly ask for it.
List<Seg.PathSegment> segmentsUp = getSegments(segmentStub, srcIsdAs, srcWildcard);
boolean[] containsIsdAs = containsIsdAs(segmentsUp, srcIsdAs, dstIsdAs);
if (containsIsdAs[1]) {
// case B: DST is core
return combineSegment(segmentsUp, brLookup);
}
segments.add(segmentsUp);
from = srcWildcard;
}

if (srcISD == dstISD) {
// cases C, D, E
// TODO this is an expensive way to find out whether DST is CORE
List<Seg.PathSegment> segmentsCoreOrDown = getSegments(segmentStub, from, dstIsdAs);
if (!segmentsCoreOrDown.isEmpty()) {
// Okay, we found a direct route from src(Wildcard) to DST
segments.add(segmentsCoreOrDown);
List<Daemon.Path> paths = combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
if (!paths.isEmpty()) {
return paths;
}
// okay, we need CORE!
// TODO this is horrible.
segments.remove(segments.size() - 1);
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
segments.add(segmentsCore);
segments.add(segmentsCoreOrDown);
return combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}
// Try again with wildcard (DST is neither core nor a child of FROM)
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
boolean[] coreHasIA = containsIsdAs(segmentsCore, from, dstIsdAs);
segments.add(segmentsCore);
if (coreHasIA[1]) {
// case D: DST is core
// TODO why is this ever used? See e.g. Test F0 111->120
return combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
} else {
from = dstWildcard;
// case C: DST is not core
// We have to query down segments because SRC may not have a segment connected to DST
List<Seg.PathSegment> segmentsDown = getSegments(segmentStub, from, dstIsdAs);
segments.add(segmentsDown);
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}
}
// remaining cases: F, G, H
List<Seg.PathSegment> segmentsCore = getSegments(segmentStub, from, dstWildcard);
boolean[] localCores = Segments.containsIsdAs(segmentsCore, srcIsdAs, dstIsdAs);
segments.add(segmentsCore);
if (localCores[1]) {
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}

List<Seg.PathSegment> segmentsDown = getSegments(segmentStub, dstWildcard, dstIsdAs);
segments.add(segmentsDown);
return Segments.combineSegments(segments, srcIsdAs, dstIsdAs, brLookup);
}

private static long toWildcard(long isdAs) {
return (isdAs >>> 48) << 48;
}
Expand Down

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