fuzz: target for shutdown

Fuzz the decoding and encoding of shutdown.

tests/fuzz/fuzz-wire-shutdown.c

@@ -0,0 +1,56 @@
+#include "config.h"
+#include <assert.h>
+#include <ccan/mem/mem.h>
+#include <common/channel_id.h>
+#include <tests/fuzz/libfuzz.h>
+#include <tests/fuzz/wire.h>
+#include <wire/peer_wire.h>
+
+struct shutdown {
+	struct channel_id channel_id;
+	u8 *scriptpubkey;
+	struct tlv_shutdown_tlvs *tlvs;
+};
+
+static void *encode(const tal_t *ctx, const struct shutdown *s)
+{
+	return towire_shutdown(ctx, &s->channel_id, s->scriptpubkey, s->tlvs);
+}
+
+static struct shutdown *decode(const tal_t *ctx, const void *p)
+{
+	struct shutdown *s = tal(ctx, struct shutdown);
+
+	if (fromwire_shutdown(s, p, &s->channel_id, &s->scriptpubkey, &s->tlvs))
+		return s;
+	return tal_free(s);
+}
+
+static bool wrong_funding_equal(const struct tlv_shutdown_tlvs_wrong_funding *x,
+				const struct tlv_shutdown_tlvs_wrong_funding *y)
+{
+	if (!x && !y)
+		return true;
+	if (!x || !y)
+		return false;
+
+	return bitcoin_txid_eq(&x->txid, &y->txid) && x->outnum == y->outnum;
+}
+
+static bool equal(const struct shutdown *x, const struct shutdown *y)
+{
+	if (!channel_id_eq(&x->channel_id, &y->channel_id))
+		return false;
+	if (!memeq(x->scriptpubkey, tal_bytelen(x->scriptpubkey),
+		   y->scriptpubkey, tal_bytelen(y->scriptpubkey)))
+		return false;
+
+	assert(x->tlvs && y->tlvs);
+	return wrong_funding_equal(x->tlvs->wrong_funding,
+				   y->tlvs->wrong_funding);
+}
+
+void run(const u8 *data, size_t size)
+{
+	test_decode_encode(data, size, WIRE_SHUTDOWN, struct shutdown);
+}