/*
This file is part of GNUnet.
- Copyright (C) 2011 GNUnet e.V.
+ Copyright (C) 2011, 2017 GNUnet e.V.
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
*/
/**
* @file cadet/test_cadet.c
- *
+ * @author Bart Polot
+ * @author Christian Grothoff
* @brief Test for the cadet service: retransmission of traffic.
*/
#include <stdio.h>
/**
* How many messages to send
*/
-#define TOTAL_PACKETS 200 /* Cannot exceed 64k! */
+#define TOTAL_PACKETS 500 /* Cannot exceed 64k! */
/**
* How long until we give up on connecting the peers?
/**
* String with test name
*/
-char *test_name;
+static char *test_name;
/**
* Flag to send traffic leaf->root in speed tests to test BCK_ACK logic.
/**
* Number of events expected to conclude the test successfully.
*/
-int ok_goal;
+static int ok_goal;
/**
* Size of each test packet
*/
-size_t size_payload = sizeof (struct GNUNET_MessageHeader) + sizeof (uint32_t);
+static size_t size_payload = sizeof (struct GNUNET_MessageHeader) + sizeof (uint32_t);
/**
* Operation to get peer ids.
*/
-struct GNUNET_TESTBED_Operation *t_op[2];
+static struct GNUNET_TESTBED_Operation *t_op[2];
/**
* Peer ids.
*/
-struct GNUNET_PeerIdentity *p_id[2];
+static struct GNUNET_PeerIdentity *p_id[2];
+
+/**
+ * Port ID
+ */
+static struct GNUNET_HashCode port;
/**
* Peer ids counter.
*/
-unsigned int p_ids;
+static unsigned int p_ids;
/**
* Is the setup initialized?
/**
* Task called to disconnect peers.
*/
-static struct GNUNET_SCHEDULER_Task * disconnect_task;
+static struct GNUNET_SCHEDULER_Task *disconnect_task;
/**
* Task To perform tests
*/
-static struct GNUNET_SCHEDULER_Task * test_task;
+static struct GNUNET_SCHEDULER_Task *test_task;
/**
- * Task called to shutdown test.
+ * Task runnining #data_task().
*/
-static struct GNUNET_SCHEDULER_Task * shutdown_handle;
+static struct GNUNET_SCHEDULER_Task *data_job;
/**
* Cadet handle for the root peer
*/
static unsigned int ka_received;
+/**
+ * How many messages were dropped by CADET because of full buffers?
+ */
+static unsigned int msg_dropped;
+
/**
* Get the client number considered as the "target" or "receiver", depending on
return peers_requested - 1;
}
+
/**
* Show the results of the test (banwidth acheived) and log them to GAUGER
*/
}
-/**
- * Shut down peergroup, clean up.
- *
- * @param cls Closure (unused).
- * @param tc Task Context.
- */
-static void
-shutdown_task (void *cls)
-{
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Ending test.\n");
- shutdown_handle = NULL;
-}
-
-
/**
* Disconnect from cadet services af all peers, call shutdown.
*
{
long line = (long) cls;
unsigned int i;
- const struct GNUNET_SCHEDULER_TaskContext *tc;
- tc = GNUNET_SCHEDULER_get_task_context ();
- if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) != 0)
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "disconnecting cadet peers due to SHUTDOWN! called from %ld\n",
- line);
- else
- GNUNET_log (GNUNET_ERROR_TYPE_INFO,
- "disconnecting cadet service of peers, called from line %ld\n",
- line);
disconnect_task = NULL;
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "disconnecting cadet service of peers, called from line %ld\n",
+ line);
for (i = 0; i < 2; i++)
{
GNUNET_TESTBED_operation_done (t_op[i]);
incoming_ch = NULL;
}
GNUNET_CADET_TEST_cleanup (test_ctx);
- if (NULL != shutdown_handle)
+ GNUNET_SCHEDULER_shutdown ();
+}
+
+
+/**
+ * Shut down peergroup, clean up.
+ *
+ * @param cls Closure (unused).
+ * @param tc Task Context.
+ */
+static void
+shutdown_task (void *cls)
+{
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Ending test.\n");
+ if (NULL != data_job)
{
- GNUNET_SCHEDULER_cancel (shutdown_handle);
+ GNUNET_SCHEDULER_cancel (data_job);
+ data_job = NULL;
+ }
+ if (NULL != test_task)
+ {
+ GNUNET_SCHEDULER_cancel (test_task);
+ test_task = NULL;
+ }
+ if (NULL != disconnect_task)
+ {
+ GNUNET_SCHEDULER_cancel (disconnect_task);
+ disconnect_task = GNUNET_SCHEDULER_add_now (&disconnect_cadet_peers,
+ (void *) __LINE__);
}
- shutdown_handle = GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
}
-
/**
* Stats callback. Finish the stats testbed operation and when all stats have
* been iterated, shutdown the test.
* operation has executed successfully.
*/
static void
-stats_cont (void *cls, struct GNUNET_TESTBED_Operation *op, const char *emsg)
+stats_cont (void *cls,
+ struct GNUNET_TESTBED_Operation *op,
+ const char *emsg)
{
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, " KA sent: %u, KA received: %u\n",
- ka_sent, ka_received);
- if (KEEPALIVE == test && (ka_sent < 2 || ka_sent > ka_received + 1))
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ " KA sent: %u, KA received: %u\n",
+ ka_sent,
+ ka_received);
+ if ( (KEEPALIVE == test) &&
+ ( (ka_sent < 2) ||
+ (ka_sent > ka_received + 1)) )
+ {
+ GNUNET_break (0);
ok--;
+ }
GNUNET_TESTBED_operation_done (stats_op);
if (NULL != disconnect_task)
GNUNET_SCHEDULER_cancel (disconnect_task);
- disconnect_task = GNUNET_SCHEDULER_add_now (&disconnect_cadet_peers, cls);
-
+ disconnect_task = GNUNET_SCHEDULER_add_now (&disconnect_cadet_peers,
+ cls);
}
* @param subsystem name of subsystem that created the statistic
* @param name the name of the datum
* @param value the current value
- * @param is_persistent GNUNET_YES if the value is persistent, GNUNET_NO if not
- * @return GNUNET_OK to continue, GNUNET_SYSERR to abort iteration
+ * @param is_persistent #GNUNET_YES if the value is persistent, #GNUNET_NO if not
+ * @return #GNUNET_OK to continue, #GNUNET_SYSERR to abort iteration
*/
static int
-stats_iterator (void *cls, const struct GNUNET_TESTBED_Peer *peer,
- const char *subsystem, const char *name,
- uint64_t value, int is_persistent)
+stats_iterator (void *cls,
+ const struct GNUNET_TESTBED_Peer *peer,
+ const char *subsystem,
+ const char *name,
+ uint64_t value,
+ int is_persistent)
{
static const char *s_sent = "# keepalives sent";
static const char *s_recv = "# keepalives received";
+ static const char *rdrops = "# messages dropped due to full buffer";
+ static const char *cdrops = "# messages dropped due to slow client";
uint32_t i;
i = GNUNET_TESTBED_get_index (peer);
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "STATS PEER %u - %s [%s]: %llu\n",
- i, subsystem, name, value);
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "STATS PEER %u - %s [%s]: %llu\n",
+ i,
+ subsystem,
+ name,
+ (unsigned long long) value);
if (0 == strncmp (s_sent, name, strlen (s_sent)) && 0 == i)
ka_sent = value;
-
if (0 == strncmp(s_recv, name, strlen (s_recv)) && peers_requested - 1 == i)
ka_received = value;
+ if (0 == strncmp(rdrops, name, strlen (rdrops)))
+ msg_dropped += value;
+ if (0 == strncmp(cdrops, name, strlen (cdrops)))
+ msg_dropped += value;
return GNUNET_OK;
}
gather_stats_and_exit (void *cls)
{
long l = (long) cls;
- const struct GNUNET_SCHEDULER_TaskContext *tc;
disconnect_task = NULL;
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, "gathering statistics from line %d\n", l);
- tc = GNUNET_SCHEDULER_get_task_context ();
- if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) != 0)
- {
- disconnect_task = GNUNET_SCHEDULER_add_now (&disconnect_cadet_peers,
- (void *) __LINE__);
- return;
- }
-
-
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ "gathering statistics from line %d\n",
+ (int) l);
if (NULL != ch)
{
if (NULL != th)
}
stats_op = GNUNET_TESTBED_get_statistics (peers_running, testbed_peers,
"cadet", NULL,
- stats_iterator, stats_cont, cls);
+ &stats_iterator, stats_cont, cls);
}
static void
abort_test (long line)
{
- if (disconnect_task != NULL)
+ if (NULL != disconnect_task)
{
GNUNET_SCHEDULER_cancel (disconnect_task);
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Aborting test from %ld\n", line);
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Aborting test from %ld\n", line);
disconnect_task = GNUNET_SCHEDULER_add_now (&disconnect_cadet_peers,
(void *) line);
}
{
struct GNUNET_CADET_Channel *channel;
static struct GNUNET_CADET_TransmitHandle **pth;
- const struct GNUNET_SCHEDULER_TaskContext *tc;
long src;
+ data_job = NULL;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Data task\n");
- tc = GNUNET_SCHEDULER_get_task_context ();
- if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) != 0)
- return;
-
if (GNUNET_YES == test_backwards)
{
channel = incoming_ch;
if (0 == i)
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING, " in 1 ms\n");
- GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS,
- &data_task, (void *) 1L);
+ data_job = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS,
+ &data_task, (void *) 1L);
}
else
{
i++;
- GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "in %u ms\n", i);
- GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply (
- GNUNET_TIME_UNIT_MILLISECONDS,
- i),
- &data_task, (void *) i);
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ "in %llu ms\n",
+ (unsigned long long) i);
+ data_job = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
+ i),
+ &data_task, (void *) i);
}
}
}
* @param size Size of the buffer we have.
* @param buf Buffer to copy data to.
*/
-size_t
+static size_t
tmt_rdy (void *cls, size_t size, void *buf)
{
struct GNUNET_MessageHeader *msg = buf;
long id = (long) cls;
unsigned int counter;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "tmt_rdy on %ld, filling buffer\n", id);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "tmt_rdy on %ld, filling buffer\n",
+ id);
if (0 == id)
th = NULL;
else if ((peers_requested - 1) == id)
GNUNET_assert (0);
counter = get_expected_target () == id ? ack_sent : data_sent;
msg_size = size_payload + counter;
- if (size < msg_size || NULL == buf)
+ GNUNET_assert (msg_size > sizeof (struct GNUNET_MessageHeader));
+ if ( (size < msg_size) ||
+ (NULL == buf) )
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"size %u, buf %p, data_sent %u, ack_received %u\n",
- size, buf, data_sent, ack_received);
+ (unsigned int) size,
+ buf,
+ data_sent,
+ ack_received);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "ok %u, ok goal %u\n", ok, ok_goal);
GNUNET_break (ok >= ok_goal - 2);
return 0;
}
msg->size = htons (msg_size);
- msg->type = htons (1);
+ msg->type = htons (GNUNET_MESSAGE_TYPE_DUMMY);
data = (uint32_t *) &msg[1];
*data = htonl (counter);
if (GNUNET_NO == initialized)
{
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "sending initializer\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "sending initializer\n");
msg_size = size_payload + 1000;
- if (SPEED_ACK == test)
+ msg->size = htons (msg_size);
+ if (SPEED_ACK == test)
data_sent++;
}
- else if (SPEED == test || SPEED_ACK == test)
+ else if ( (SPEED == test) ||
+ (SPEED_ACK == test) )
{
if (get_expected_target() == id)
ack_sent++;
else
data_sent++;
counter++;
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, " Sent message %d size %u\n",
- counter, msg_size);
- if (data_sent < TOTAL_PACKETS && SPEED == test)
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ " Sent message %u size %u\n",
+ counter,
+ (unsigned int) msg_size);
+ if ( (data_sent < TOTAL_PACKETS) &&
+ (SPEED == test) )
{
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " Scheduling message %d\n",
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ " Scheduling message %d\n",
counter + 1);
- GNUNET_SCHEDULER_add_now (&data_task, NULL);
+ data_job = GNUNET_SCHEDULER_add_now (&data_task, NULL);
}
}
/**
* Function is called whenever a message is received.
*
- * @param cls closure (set from GNUNET_CADET_connect, peer number)
+ * @param cls closure (set from GNUNET_CADET_connect(), peer number)
* @param channel connection to the other end
* @param channel_ctx place to store local state associated with the channel
* @param message the actual message
- * @return GNUNET_OK to keep the connection open,
- * GNUNET_SYSERR to close it (signal serious error)
+ * @return #GNUNET_OK to keep the connection open,
+ * #GNUNET_SYSERR to close it (signal serious error)
*/
-int
-data_callback (void *cls, struct GNUNET_CADET_Channel *channel,
+static int
+data_callback (void *cls,
+ struct GNUNET_CADET_Channel *channel,
void **channel_ctx,
const struct GNUNET_MessageHeader *message)
{
{
if (NULL != disconnect_task)
{
- GNUNET_log (GNUNET_ERROR_TYPE_INFO, " reschedule timeout\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+ " reschedule timeout\n");
GNUNET_SCHEDULER_cancel (disconnect_task);
disconnect_task = GNUNET_SCHEDULER_add_delayed (SHORT_TIME,
&gather_stats_and_exit,
if (SPEED == test)
{
GNUNET_assert (peers_requested - 1 == client);
- GNUNET_SCHEDULER_add_now (&data_task, NULL);
+ data_job = GNUNET_SCHEDULER_add_now (&data_task, NULL);
return GNUNET_OK;
}
}
* {callback_function, message_type, size_expected}
*/
static struct GNUNET_CADET_MessageHandler handlers[] = {
- {&data_callback, 1, sizeof (struct GNUNET_MessageHeader)},
+ {&data_callback,
+ GNUNET_MESSAGE_TYPE_DUMMY,
+ sizeof (struct GNUNET_MessageHeader)},
{NULL, 0, 0}
};
* (can be NULL -- that's not an error).
*/
static void *
-incoming_channel (void *cls, struct GNUNET_CADET_Channel *channel,
- const struct GNUNET_PeerIdentity *initiator,
- uint32_t port, enum GNUNET_CADET_ChannelOption options)
+incoming_channel (void *cls,
+ struct GNUNET_CADET_Channel *channel,
+ const struct GNUNET_PeerIdentity *initiator,
+ const struct GNUNET_HashCode *port,
+ enum GNUNET_CADET_ChannelOption options)
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
- "Incoming channel from %s to peer %d\n",
- GNUNET_i2s (initiator), (long) cls);
+ "Incoming channel from %s to peer %d:%s\n",
+ GNUNET_i2s (initiator),
+ (int) (long) cls, GNUNET_h2s (port));
ok++;
GNUNET_log (GNUNET_ERROR_TYPE_INFO, " ok: %d\n", ok);
if ((long) cls == peers_requested - 1)
+ {
+ if (NULL != incoming_ch)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ "Duplicate incoming channel for client %lu\n",
+ (long) cls);
+ GNUNET_break(0);
+ }
incoming_ch = channel;
+ }
else
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "Incoming channel for unknown client %lu\n", (long) cls);
- GNUNET_break(0);
+ "Incoming channel for unexpected peer #%lu\n",
+ (long) cls);
+ GNUNET_break (0);
}
if (NULL != disconnect_task)
{
return NULL;
}
+
/**
* Function called whenever an inbound channel is destroyed. Should clean up
* any associated state.
* with the channel is stored
*/
static void
-channel_cleaner (void *cls, const struct GNUNET_CADET_Channel *channel,
+channel_cleaner (void *cls,
+ const struct GNUNET_CADET_Channel *channel,
void *channel_ctx)
{
long i = (long) cls;
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
- "Incoming channel disconnected at peer %ld\n", i);
+ "Incoming channel disconnected at peer %ld\n",
+ i);
if (peers_running - 1 == i)
{
ok++;
{
if (P2P_SIGNAL == test)
{
- ok ++;
+ ok++;
}
GNUNET_break (channel == ch);
ch = NULL;
}
else
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "Unknown peer! %d\n", i);
+ "Unknown peer! %d\n",
+ (int) i);
GNUNET_log (GNUNET_ERROR_TYPE_INFO, " ok: %d\n", ok);
if (NULL != disconnect_task)
disconnect_task = GNUNET_SCHEDULER_add_now (&gather_stats_and_exit,
(void *) __LINE__);
}
-
- return;
}
do_test (void *cls)
{
enum GNUNET_CADET_ChannelOption flags;
- const struct GNUNET_SCHEDULER_TaskContext *tc;
-
- tc = GNUNET_SCHEDULER_get_task_context ();
- if ((GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason) != 0)
- return;
-
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "do_test\n");
+ test_task = NULL;
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "do_test\n");
if (NULL != disconnect_task)
{
GNUNET_SCHEDULER_cancel (disconnect_task);
+ disconnect_task = NULL;
}
flags = GNUNET_CADET_OPTION_DEFAULT;
test = SPEED;
flags |= GNUNET_CADET_OPTION_RELIABLE;
}
- ch = GNUNET_CADET_channel_create (h1, NULL, p_id[1], 1, flags);
- disconnect_task = GNUNET_SCHEDULER_add_delayed (SHORT_TIME,
- &gather_stats_and_exit,
- (void *) __LINE__);
+ ch = GNUNET_CADET_channel_create (h1,
+ NULL,
+ p_id[1],
+ &port,
+ flags);
+
+ disconnect_task
+ = GNUNET_SCHEDULER_add_delayed (SHORT_TIME,
+ &gather_stats_and_exit,
+ (void *) __LINE__);
if (KEEPALIVE == test)
return; /* Don't send any data. */
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending data initializer...\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Sending data initializer...\n");
data_received = 0;
data_sent = 0;
ack_received = 0;
ack_sent = 0;
- th = GNUNET_CADET_notify_transmit_ready (ch, GNUNET_NO,
+ th = GNUNET_CADET_notify_transmit_ready (ch,
+ GNUNET_NO,
GNUNET_TIME_UNIT_FOREVER_REL,
size_payload + 1000,
&tmt_rdy, (void *) 0L);
}
+
/**
* Callback to be called when the requested peer information is available
*
{
long i = (long) cls;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "id callback for %ld\n", i);
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "id callback for %ld\n", i);
- if (NULL == pinfo || NULL != emsg)
+ if ( (NULL == pinfo) ||
+ (NULL != emsg) )
{
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "pi_cb: %s\n", emsg);
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "pi_cb: %s\n", emsg);
abort_test (__LINE__);
return;
}
p_id[i] = pinfo->result.id;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " id: %s\n", GNUNET_i2s (p_id[i]));
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ " id: %s\n", GNUNET_i2s (p_id[i]));
p_ids++;
if (p_ids < 2)
return;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Got all IDs, starting test\n");
+ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+ "Got all IDs, starting test\n");
test_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
- &do_test, NULL);
+ &do_test,
+ NULL);
}
+
/**
* test main: start test when all peers are connected
*
disconnect_task = GNUNET_SCHEDULER_add_delayed (SHORT_TIME,
&disconnect_cadet_peers,
(void *) __LINE__);
- shutdown_handle = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
- &shutdown_task, NULL);
+ GNUNET_SCHEDULER_add_shutdown (&shutdown_task, NULL);
t_op[0] = GNUNET_TESTBED_peer_get_information (peers[0],
GNUNET_TESTBED_PIT_IDENTITY,
&pi_cb, (void *) 0L);
main (int argc, char *argv[])
{
initialized = GNUNET_NO;
- static uint32_t ports[2];
+ static const struct GNUNET_HashCode *ports[2];
const char *config_file;
+ char port_id[] = "test port";
+ GNUNET_CRYPTO_hash (port_id, sizeof (port_id), &port);
GNUNET_log_setup ("test", "DEBUG", NULL);
config_file = "test_cadet.conf";
}
p_ids = 0;
- ports[0] = 1;
- ports[1] = 0;
+ ports[0] = &port;
+ ports[1] = NULL;
GNUNET_CADET_TEST_run ("test_cadet_small",
config_file,
peers_requested,
&channel_cleaner,
handlers,
ports);
+ if (NULL != strstr (argv[0], "_reliable"))
+ msg_dropped = 0; /* dropped should be retransmitted */
- if (ok_goal > ok)
+ if (ok_goal > ok - msg_dropped)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"FAILED! (%d/%d)\n", ok, ok_goal);
projects / oweals / gnunet.git / blobdiff