eth: enforce announcement metadatas and drop peers violating the prot…

…ocol (ethereum#28261)

* eth: enforce announcement metadatas and drop peers violating the protocol

* eth/fetcher: relax eth/68 validation a bit for flakey clients

* tests/fuzzers/txfetcher: pull in suggestion from Marius

* eth/fetcher: add tests for peer dropping

* eth/fetcher: linter linter linter linter linter

eth/fetcher/tx_fetcher.go

@@ -600,9 +600,8 @@ func (f *TxFetcher) loop() {
 								log.Warn("Announced transaction type mismatch", "peer", peer, "tx", hash, "type", delivery.metas[i].kind, "ann", meta.kind)
 								f.dropPeer(peer)
 							} else if delivery.metas[i].size != meta.size {
+								log.Warn("Announced transaction size mismatch", "peer", peer, "tx", hash, "size", delivery.metas[i].size, "ann", meta.size)
 								if math.Abs(float64(delivery.metas[i].size)-float64(meta.size)) > 8 {
-									log.Warn("Announced transaction size mismatch", "peer", peer, "tx", hash, "size", delivery.metas[i].size, "ann", meta.size)
-
 									// Normally we should drop a peer considering this is a protocol violation.
 									// However, due to the RLP vs consensus format messyness, allow a few bytes
 									// wiggle-room where we only warn, but don't drop.
@@ -626,9 +625,8 @@ func (f *TxFetcher) loop() {
 								log.Warn("Announced transaction type mismatch", "peer", peer, "tx", hash, "type", delivery.metas[i].kind, "ann", meta.kind)
 								f.dropPeer(peer)
 							} else if delivery.metas[i].size != meta.size {
+								log.Warn("Announced transaction size mismatch", "peer", peer, "tx", hash, "size", delivery.metas[i].size, "ann", meta.size)
 								if math.Abs(float64(delivery.metas[i].size)-float64(meta.size)) > 8 {
-									log.Warn("Announced transaction size mismatch", "peer", peer, "tx", hash, "size", delivery.metas[i].size, "ann", meta.size)
-
 									// Normally we should drop a peer considering this is a protocol violation.
 									// However, due to the RLP vs consensus format messyness, allow a few bytes
 									// wiggle-room where we only warn, but don't drop.

eth/fetcher/tx_fetcher_test.go

@@ -186,7 +186,7 @@ func TestTransactionFetcherWaiting(t *testing.T) {
 // waitlist, and none of them are scheduled for retrieval until the wait expires.
 //
 // This test is an extended version of TestTransactionFetcherWaiting. It's mostly
-// to cover the metadata checks without bloating up the basic behavioral tests
+// to cover the metadata checkes without bloating up the basic behavioral tests
 // with all the useless extra fields.
 func TestTransactionFetcherWaitingWithMeta(t *testing.T) {
 	testTransactionFetcherParallel(t, txFetcherTest{
@@ -1726,7 +1726,7 @@ func testTransactionFetcher(t *testing.T, tt txFetcherTest) {
 						if (meta == nil && (ann.kind != nil || ann.size != nil)) ||
 							(meta != nil && (ann.kind == nil || ann.size == nil)) ||
 							(meta != nil && (meta.kind != *ann.kind || meta.size != *ann.size)) {
-							t.Errorf("step %d, peer %s, hash %x: waitslot metadata mismatch: want %v, have %v/%v", i, peer, ann.hash, meta, *ann.kind, *ann.size)
+							t.Errorf("step %d, peer %s, hash %x: waitslot metadata mismatch: want %v, have %v/%v", i, peer, ann.hash, meta, ann.kind, ann.size)
 						}
 					}
 				}
@@ -1795,7 +1795,7 @@ func testTransactionFetcher(t *testing.T, tt txFetcherTest) {
 						if (meta == nil && (ann.kind != nil || ann.size != nil)) ||
 							(meta != nil && (ann.kind == nil || ann.size == nil)) ||
 							(meta != nil && (meta.kind != *ann.kind || meta.size != *ann.size)) {
-							t.Errorf("step %d, peer %s, hash %x: announce metadata mismatch: want %v, have %v/%v", i, peer, ann.hash, meta, *ann.kind, *ann.size)
+							t.Errorf("step %d, peer %s, hash %x: announce metadata mismatch: want %v, have %v/%v", i, peer, ann.hash, meta, ann.kind, ann.size)
 						}
 					}
 				}