fuzz: target for closing_signed

Fuzz the decoding and encoding of closing_signed.

tests/fuzz/fuzz-wire-closing_signed.c

@@ -0,0 +1,48 @@
+#include "config.h"
+#include <assert.h>
+#include <ccan/mem/mem.h>
+#include <stdint.h>
+#include <tests/fuzz/libfuzz.h>
+#include <tests/fuzz/wire.h>
+#include <wire/peer_wire.h>
+
+struct closing_signed {
+	struct channel_id channel_id;
+	struct amount_sat fee_satoshis;
+	secp256k1_ecdsa_signature signature;
+	struct tlv_closing_signed_tlvs *tlvs;
+};
+
+static void *encode(const tal_t *ctx, const struct closing_signed *s)
+{
+	return towire_closing_signed(ctx, &s->channel_id, s->fee_satoshis,
+				     &s->signature, s->tlvs);
+}
+
+static struct closing_signed *decode(const tal_t *ctx, const void *p)
+{
+	struct closing_signed *s = tal(ctx, struct closing_signed);
+
+	if (fromwire_closing_signed(s, p, &s->channel_id, &s->fee_satoshis,
+				    &s->signature, &s->tlvs))
+		return s;
+	return tal_free(s);
+}
+
+static bool equal(const struct closing_signed *x,
+		  const struct closing_signed *y)
+{
+	size_t upto_tlvs = (uintptr_t)&x->tlvs - (uintptr_t)x;
+	if (memcmp(x, y, upto_tlvs) != 0)
+		return false;
+
+	assert(x->tlvs && y->tlvs);
+	return memeq(x->tlvs->fee_range, tal_bytelen(x->tlvs->fee_range),
+		     y->tlvs->fee_range, tal_bytelen(y->tlvs->fee_range));
+}
+
+void run(const u8 *data, size_t size)
+{
+	test_decode_encode(data, size, WIRE_CLOSING_SIGNED,
+			   struct closing_signed);
+}