msgb: add test helpers

It's often handy to compare certain msgb layer to a given array and
print the position where they differ. Add simple pretty-printer and
corresponding L* wrappers.

Change-Id: I3bc95f2f5ab6e3f4b502647fb3e0aaaf1f7c4cf5

2 files changed, 231 insertions, 0 deletions

diff --git a/include/osmocom/core/msgb.h b/include/osmocom/core/msgb.h
index 1bb5fe59..b7c84221 100644
--- a/include/osmocom/core/msgb.h
+++ b/include/osmocom/core/msgb.h
@@ -560,6 +560,145 @@ static inline int msgb_test_invariant(const struct msgb *msg)
 	return lbound <= msg->head +  msg->data_len;
 }
 
+
+/* msgb data comparison helpers */
+
+/*! Compare: check data in msgb against given data
+ *  \param[in] msg message buffer
+ *  \param[in] data expected data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb content is equal to the given data
+ */
+#define msgb_eq_data(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 0, msg, data, len, false)
+
+/*! Compare: check L1 data in msgb against given data
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L1 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L1 content is equal to the given data
+ */
+#define msgb_eq_l1_data(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 1, msg, data, len, false)
+
+/*! Compare: check L2 data in msgb against given data
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L2 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L2 content is equal to the given data
+ */
+#define msgb_eq_l2_data(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 2, msg, data, len, false)
+
+/*! Compare: check L3 data in msgb against given data
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L3 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L3 content is equal to the given data
+ */
+#define msgb_eq_l3_data(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 3, msg, data, len, false)
+
+/*! Compare: check L4 data in msgb against given data
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L4 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L4 content is equal to the given data
+ */
+#define msgb_eq_l4_data(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 4, msg, data, len, false)
+
+
+/* msgb test/debug helpers */
+
+/*! Compare and print: check data in msgb against given data and print errors if any
+ *  \param[in] msg message buffer
+ *  \param[in] data expected data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb content is equal to the given data
+ */
+#define msgb_eq_data_print(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 0, msg, data, len, true)
+
+/*! Compare and print: check L1 data in msgb against given data and print errors if any
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L1 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L1 content is equal to the given data
+ */
+#define msgb_eq_l1_data_print(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 1, msg, data, len, true)
+
+/*! Compare and print: check L2 data in msgb against given data and print errors if any
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L2 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L2 content is equal to the given data
+ */
+#define msgb_eq_l2_data_print(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 2, msg, data, len, true)
+
+/*! Compare and print: check L3 data in msgb against given data and print errors if any
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L3 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L3 content is equal to the given data
+ */
+#define msgb_eq_l3_data_print(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 3, msg, data, len, true)
+
+
+/*! Compare and print: check L4 data in msgb against given data and print errors if any
+ *  \param[in] msg message buffer
+ *  \param[in] data expected L4 data
+ *  \param[in] len length of data
+ *  \returns boolean indicating whether msgb L4 content is equal to the given data
+ */
+#define msgb_eq_l4_data_print(msg, data, len)				\
+	_msgb_eq(__FILE__, __LINE__, __func__, 4, msg, data, len, true)
+
+bool _msgb_eq(const char *file, size_t line, const char *func, uint8_t level,
+	      const struct msgb *msg, const uint8_t *data, size_t len, bool print);
+
+
+/* msgb data comparison */
+
+/*! Compare msgbs
+ *  \param[in] msg1 message buffer
+ *  \param[in] msg2 reference message buffer
+ *  \returns boolean indicating whether msgb content is equal
+ */
+#define msgb_eq(msg1, msgb2, len) msgb_eq_data(msg1, msgb_data(msg2), msgb_length(msg2))
+
+/*! Compare msgbs L1 content
+ *  \param[in] msg1 message buffer
+ *  \param[in] msg2 reference message buffer
+ *  \returns boolean indicating whether msgb L1 content is equal
+ */
+#define msgb_eq_l1(msg1, msgb2, len) msgb_eq_l1_data(msg1, msgb_l1(msg2), msgb_l1len(msg2))
+
+/*! Compare msgbs L2 content
+ *  \param[in] msg1 message buffer
+ *  \param[in] msg2 reference message buffer
+ *  \returns boolean indicating whether msgb L2 content is equal
+ */
+#define msgb_eq_l2(msg1, msgb2, len) msgb_eq_l2_data(msg1, msgb_l2(msg2), msgb_l2len(msg2))
+
+/*! Compare msgbs L3 content
+ *  \param[in] msg1 message buffer
+ *  \param[in] msg2 reference message buffer
+ *  \returns boolean indicating whether msgb L3 content is equal
+ */
+#define msgb_eq_l3(msg1, msgb2, len) msgb_eq_l3_data(msg1, msgb_l3(msg2), msgb_l3len(msg2))
+
+/*! Compare msgbs L4 content
+ *  \param[in] msg1 message buffer
+ *  \param[in] msg2 reference message buffer
+ *  \returns boolean indicating whether msgb L4 content is equal
+ */
+#define msgb_eq_l4(msg1, msgb2, len) msgb_eq_l4_data(msg1, msgb_l4(msg2), msgb_l4len(msg2))
+
+
 /* non inline functions to ease binding */
 
 uint8_t *msgb_data(const struct msgb *msg);
diff --git a/src/msgb.c b/src/msgb.c
index 844cfc61..9cd59c67 100644
--- a/src/msgb.c
+++ b/src/msgb.c
@@ -173,6 +173,98 @@ uint8_t *msgb_data(const struct msgb *msg)
 	return msg->data;
 }
 
+/*! Compare and print: check data in msgb against given data and print errors if any
+ *  \param[in] file text prefix, usually __FILE__, ignored if print == false
+ *  \param[in] line numeric prefix, usually __LINE__, ignored if print == false
+ *  \param[in] func text prefix, usually __func__, ignored if print == false
+ *  \param[in] level while layer (L1, L2 etc) data should be compared against
+ *  \param[in] msg message buffer
+ *  \param[in] data expected data
+ *  \param[in] len length of data
+ *  \param[in] print boolean indicating whether we should print anything to stdout
+ *  \returns boolean indicating whether msgb content is equal to a given data
+ *
+ * This function is not intended to be called directly but rather used through corresponding macro wrappers.
+ */
+bool _msgb_eq(const char *file, size_t line, const char *func, uint8_t level,
+	      const struct msgb *msg, const uint8_t *data, size_t len, bool print)
+{
+	const char *m_dump;
+	unsigned int m_len, i;
+	uint8_t *m_data;
+
+	if (!msg) {
+		if (print)
+			LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line, "%s() NULL msg comparison\n", func);
+		return false;
+	}
+
+	if (!data) {
+		if (print)
+			LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line, "%s() NULL comparison data\n", func);
+		return false;
+	}
+
+	switch (level) {
+	case 0:
+		m_len = msgb_length(msg);
+		m_data = msgb_data(msg);
+		m_dump = print ? msgb_hexdump(msg) : NULL;
+		break;
+	case 1:
+		m_len = msgb_l1len(msg);
+		m_data = msgb_l1(msg);
+		m_dump = print ? msgb_hexdump_l1(msg) : NULL;
+		break;
+	case 2:
+		m_len = msgb_l2len(msg);
+		m_data = msgb_l2(msg);
+		m_dump = print ? msgb_hexdump_l2(msg) : NULL;
+		break;
+	case 3:
+		m_len = msgb_l3len(msg);
+		m_data = msgb_l3(msg);
+		m_dump = print ? msgb_hexdump_l3(msg) : NULL;
+		break;
+	case 4:
+		m_len = msgb_l4len(msg);
+		m_data = msgb_l4(msg);
+		m_dump = print ? msgb_hexdump_l4(msg) : NULL;
+		break;
+	default:
+		LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+			"%s() FIXME: unexpected comparison level %u\n", func, level);
+		return false;
+	}
+
+	if (m_len != len) {
+		if (print)
+			LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+				"%s() Length mismatch: %d != %zu, %s\n", func, m_len, len, m_dump);
+		return false;
+	}
+
+	if (memcmp(m_data, data, len) == 0)
+		return true;
+
+	if (!print)
+		return false;
+
+	LOGPSRC(DLGLOBAL, LOGL_FATAL, file, line,
+		"%s() L%u data mismatch:\nexpected %s\n         ", func, level, osmo_hexdump(data, len));
+
+	for(i = 0; i < len; i++)
+		if (data[i] != m_data[i]) {
+			LOGPC(DLGLOBAL, LOGL_FATAL, "!!\n");
+			break;
+		} else
+			LOGPC(DLGLOBAL, LOGL_FATAL, ".. ");
+
+	LOGPC(DLGLOBAL, LOGL_FATAL, "    msgb %s\n", m_dump);
+
+	return false;
+}
+
 /*! get length of message buffer
  *  \param[in] msg message buffer
  *  \returns length of data section in message buffer