[ping] Allow termination after a specified number of packets

Add the "-c <count>" option to the "ping" command, allowing for
automatic termination after a specified number of packets.

When a number of packets is specified:

  - if a serious error (i.e. length mismatch or content mismatch)
    occurs, then the ping will be immediately terminated with the relevant
    status code;

  - if at least one response is received successfully, and all errors
    are non-serious (i.e. timeouts or out-of-sequence responses), then
    the ping will be terminated after the final response (or timeout)
    with a success status;

  - if no responses are received successfully, then the ping will be
    terminated after the final timeout with ETIMEDOUT.

If no number of packets is specified, then the ping will continue
until manually interrupted.

Originally-implemented-by: Cedric Levasseur <cyr-ius@ipocus.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/pinger.c

 	uint16_t sequence;
 	/** Response for current sequence number is still pending */
 	int pending;
+	/** Number of remaining expiry events (zero to continue indefinitely) */
+	unsigned int remaining;
+	/** Return status */
+	int rc;
 
 	/** Callback function
 	 *
 	/* If no response has been received, notify the callback function */
 	if ( pinger->pending )
 		pinger->callback ( NULL, pinger->sequence, 0, -ETIMEDOUT );
-	pinger->pending = 1;
+
+	/* Check for termination */
+	if ( pinger->remaining && ( --pinger->remaining == 0 ) ) {
+		pinger_close ( pinger, pinger->rc );
+		return;
+	}
 
 	/* Increase sequence number */
 	pinger->sequence++;
 	 * case the transmission attempt fails.
 	 */
 	start_timer_fixed ( &pinger->timer, pinger->timeout );
+	pinger->pending = 1;
 
 	/* Allocate I/O buffer */
 	iobuf = xfer_alloc_iob ( &pinger->xfer, pinger->len );
 			    struct xfer_metadata *meta ) {
 	size_t len = iob_len ( iobuf );
 	uint16_t sequence = meta->offset;
+	int terminate = 0;
 	int rc;
 
 	/* Clear response pending flag, if applicable */
 
 	/* Check for errors */
 	if ( len != pinger->len ) {
+		/* Incorrect length: terminate immediately if we are
+		 * not pinging indefinitely.
+		 */
 		DBGC ( pinger, "PINGER %p received incorrect length %zd "
 		       "(expected %zd)\n", pinger, len, pinger->len );
 		rc = -EPROTO_LEN;
+		terminate = ( pinger->remaining != 0 );
 	} else if ( ( rc = pinger_verify ( pinger, iobuf->data ) ) != 0 ) {
+		/* Incorrect data: terminate immediately if we are not
+		 * pinging indefinitely.
+		 */
 		DBGC ( pinger, "PINGER %p received incorrect data:\n", pinger );
 		DBGC_HDA ( pinger, 0, iobuf->data, iob_len ( iobuf ) );
+		terminate = ( pinger->remaining != 0 );
 	} else if ( sequence != pinger->sequence ) {
+		/* Incorrect sequence number (probably a delayed response):
+		 * report via callback but otherwise ignore.
+		 */
 		DBGC ( pinger, "PINGER %p received sequence %d (expected %d)\n",
 		       pinger, sequence, pinger->sequence );
 		rc = -EPROTO_SEQ;
+		terminate = 0;
 	} else {
+		/* Success: record that a packet was successfully received,
+		 * and terminate if we expect to send no further packets.
+		 */
 		rc = 0;
+		pinger->rc = 0;
+		terminate = ( pinger->remaining == 1 );
 	}
 
 	/* Discard I/O buffer */
 	/* Notify callback function */
 	pinger->callback ( meta->src, sequence, len, rc );
 
+	/* Terminate if applicable */
+	if ( terminate )
+		pinger_close ( pinger, rc );
+
 	return rc;
 }
 
  * @v hostname		Hostname to ping
  * @v timeout		Timeout (in ticks)
  * @v len		Payload length
+ * @v count		Number of packets to send (or zero for no limit)
  * @ret rc		Return status code
  */
 int create_pinger ( struct interface *job, const char *hostname,
-		    unsigned long timeout, size_t len,
+		    unsigned long timeout, size_t len, unsigned int count,
 		    void ( * callback ) ( struct sockaddr *src,
 					  unsigned int sequence, size_t len,
 					  int rc ) ) {
 	timer_init ( &pinger->timer, pinger_expired, &pinger->refcnt );
 	pinger->timeout = timeout;
 	pinger->len = len;
+	pinger->remaining = ( count ? ( count + 1 /* Initial packet */ ) : 0 );
 	pinger->callback = callback;
+	pinger->rc = -ETIMEDOUT;
 
 	/* Open socket */
 	if ( ( rc = xfer_open_named_socket ( &pinger->xfer, SOCK_ECHO, NULL,

src/hci/commands/ping_cmd.c

 	unsigned int size;
 	/** Timeout (in ms) */
 	unsigned long timeout;
+	/** Number of packets to send (or zero for no limit) */
+	unsigned int count;
 };
 
 /** "ping" option list */
 		      struct ping_options, size, parse_integer ),
 	OPTION_DESC ( "timeout", 't', required_argument,
 		      struct ping_options, timeout, parse_timeout ),
+	OPTION_DESC ( "count", 'c', required_argument,
+		      struct ping_options, count, parse_integer ),
 };
 
 /** "ping" command descriptor */
 	hostname = argv[optind];
 
 	/* Ping */
-	if ( ( rc = ping ( hostname, opts.timeout, opts.size ) ) != 0 )
+	if ( ( rc = ping ( hostname, opts.timeout, opts.size,
+			   opts.count ) ) != 0 )
 		return rc;
 
 	return 0;

src/include/ipxe/pinger.h

 
 extern int create_pinger ( struct interface *job, const char *hostname,
 			   unsigned long timeout, size_t len,
+			   unsigned int count,
 			   void ( * callback ) ( struct sockaddr *peer,
 						 unsigned int sequence,
 						 size_t len,

src/include/usr/pingmgmt.h

 
 #include <stdint.h>
 
-extern int ping ( const char *hostname, unsigned long timeout, size_t len );
+extern int ping ( const char *hostname, unsigned long timeout, size_t len,
+		  unsigned int count );
 
 #endif /* _USR_PINGMGMT_H */

src/usr/pingmgmt.c

  * @v hostname		Hostname
  * @v timeout		Timeout between pings, in ticks
  * @v len		Payload length
+ * @v count		Number of packets to send (or zero for no limit)
  * @ret rc		Return status code
  */
-int ping ( const char *hostname, unsigned long timeout, size_t len ) {
+int ping ( const char *hostname, unsigned long timeout, size_t len,
+	   unsigned int count ) {
 	int rc;
 
 	/* Create pinger */
-	if ( ( rc = create_pinger ( &monojob, hostname, timeout,
-				    len, ping_callback ) ) != 0 ) {
+	if ( ( rc = create_pinger ( &monojob, hostname, timeout, len,
+				    count, ping_callback ) ) != 0 ) {
 		printf ( "Could not start ping: %s\n", strerror ( rc ) );
 		return rc;
 	}