[ping] Add generic ping mechanism

Add generic pinger mechanism (analogous to the generic downloader
mechanism) which opens a ping socket, transmits ping requests, and
passes information about ping replies to a callback function.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/pinger.c

@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/interface.h>
+#include <ipxe/job.h>
+#include <ipxe/xfer.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/open.h>
+#include <ipxe/socket.h>
+#include <ipxe/retry.h>
+#include <ipxe/pinger.h>
+
+/** @file
+ *
+ * ICMP ping sender
+ *
+ */
+
+/* Disambiguate the various error causes */
+#define EPROTO_LEN __einfo_error ( EINFO_EPROTO_LEN )
+#define EINFO_EPROTO_LEN __einfo_uniqify ( EINFO_EPROTO, 0x01, \
+					   "Incorrect reply length" )
+#define EPROTO_DATA __einfo_error ( EINFO_EPROTO_DATA )
+#define EINFO_EPROTO_DATA __einfo_uniqify ( EINFO_EPROTO, 0x02, \
+					    "Incorrect reply data" )
+#define EPROTO_SEQ __einfo_error ( EINFO_EPROTO_SEQ )
+#define EINFO_EPROTO_SEQ __einfo_uniqify ( EINFO_EPROTO, 0x03, \
+					   "Delayed or out-of-sequence reply" )
+
+/** A pinger */
+struct pinger {
+	/** Reference count */
+	struct refcnt refcnt;
+
+	/** Job control interface */
+	struct interface job;
+	/** Data transfer interface */
+	struct interface xfer;
+
+	/** Timer */
+	struct retry_timer timer;
+	/** Timeout */
+	unsigned long timeout;
+
+	/** Payload length */
+	size_t len;
+	/** Current sequence number */
+	uint16_t sequence;
+
+	/** Callback function
+	 *
+	 * @v src		Source socket address
+	 * @v sequence		Sequence number
+	 * @v len		Payload length
+	 * @v rc		Status code
+	 */
+	void ( * callback ) ( struct sockaddr *src, unsigned int sequence,
+			      size_t len, int rc );
+};
+
+/**
+ * Generate payload
+ *
+ * @v pinger		Pinger
+ * @v data		Data buffer
+ */
+static void pinger_generate ( struct pinger *pinger, void *data ) {
+	uint8_t *bytes = data;
+	unsigned int i;
+
+	/* Generate byte sequence */
+	for ( i = 0 ; i < pinger->len ; i++ )
+		bytes[i] = ( i & 0xff );
+}
+
+/**
+ * Verify payload
+ *
+ * @v pinger		Pinger
+ * @v data		Data buffer
+ * @ret rc		Return status code
+ */
+static int pinger_verify ( struct pinger *pinger, const void *data ) {
+	const uint8_t *bytes = data;
+	unsigned int i;
+
+	/* Check byte sequence */
+	for ( i = 0 ; i < pinger->len ; i++ ) {
+		if ( bytes[i] != ( i & 0xff ) )
+			return -EPROTO_DATA;
+	}
+
+	return 0;
+}
+
+/**
+ * Close pinger
+ *
+ * @v pinger		Pinger
+ * @v rc		Reason for close
+ */
+static void pinger_close ( struct pinger *pinger, int rc ) {
+
+	/* Stop timer */
+	stop_timer ( &pinger->timer );
+
+	/* Shut down interfaces */
+	intf_shutdown ( &pinger->xfer, rc );
+	intf_shutdown ( &pinger->job, rc );
+}
+
+/**
+ * Handle data transfer window change
+ *
+ * @v pinger		Pinger
+ */
+static void pinger_window_changed ( struct pinger *pinger ) {
+
+	/* Do nothing if timer is already running */
+	if ( timer_running ( &pinger->timer ) )
+		return;
+
+	/* Start timer when window opens for the first time */
+	if ( xfer_window ( &pinger->xfer ) )
+		start_timer_nodelay ( &pinger->timer );
+}
+
+/**
+ * Handle timer expiry
+ *
+ * @v timer		Timer
+ * @v over		Failure indicator
+ */
+static void pinger_expired ( struct retry_timer *timer, int over __unused ) {
+	struct pinger *pinger = container_of ( timer, struct pinger, timer );
+	struct xfer_metadata meta;
+	struct io_buffer *iobuf;
+	int rc;
+
+	/* Increase sequence number */
+	pinger->sequence++;
+
+	/* Restart timer.  Do this before attempting to transmit, in
+	 * case the transmission attempt fails.
+	 */
+	start_timer_fixed ( &pinger->timer, pinger->timeout );
+
+	/* Allocate I/O buffer */
+	iobuf = xfer_alloc_iob ( &pinger->xfer, pinger->len );
+	if ( ! iobuf ) {
+		DBGC ( pinger, "PINGER %p could not allocate I/O buffer\n",
+		       pinger );
+		return;
+	}
+
+	/* Generate payload */
+	pinger_generate ( pinger, iob_put ( iobuf, pinger->len ) );
+
+	/* Generate metadata */
+	memset ( &meta, 0, sizeof ( meta ) );
+	meta.flags = XFER_FL_ABS_OFFSET;
+	meta.offset = pinger->sequence;
+
+	/* Transmit packet */
+	if ( ( rc = xfer_deliver ( &pinger->xfer, iobuf, &meta ) ) != 0 ) {
+		DBGC ( pinger, "PINGER %p could not transmit: %s\n",
+		       pinger, strerror ( rc ) );
+		return;
+	}
+}
+
+/**
+ * Handle received data
+ *
+ * @v pinger		Pinger
+ * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata
+ * @ret rc		Return status code
+ */
+static int pinger_deliver ( struct pinger *pinger, struct io_buffer *iobuf,
+			    struct xfer_metadata *meta ) {
+	size_t len = iob_len ( iobuf );
+	uint16_t sequence = meta->offset;
+	int rc;
+
+	/* Check for errors */
+	if ( len != pinger->len ) {
+		DBGC ( pinger, "PINGER %p received incorrect length %zd "
+		       "(expected %zd)\n", pinger, len, pinger->len );
+		rc = -EPROTO_LEN;
+	} else if ( ( rc = pinger_verify ( pinger, iobuf->data ) ) != 0 ) {
+		DBGC ( pinger, "PINGER %p received incorrect data:\n", pinger );
+		DBGC_HDA ( pinger, 0, iobuf->data, iob_len ( iobuf ) );
+	} else if ( sequence != pinger->sequence ) {
+		DBGC ( pinger, "PINGER %p received sequence %d (expected %d)\n",
+		       pinger, sequence, pinger->sequence );
+		rc = -EPROTO_SEQ;
+	} else {
+		rc = 0;
+	}
+
+	/* Discard I/O buffer */
+	free_iob ( iobuf );
+
+	/* Notify callback function */
+	pinger->callback ( meta->src, sequence, len, rc );
+
+	return rc;
+}
+
+/** Pinger data transfer interface operations */
+static struct interface_operation pinger_xfer_op[] = {
+	INTF_OP ( xfer_deliver, struct pinger *, pinger_deliver ),
+	INTF_OP ( xfer_window_changed, struct pinger *, pinger_window_changed ),
+	INTF_OP ( intf_close, struct pinger *, pinger_close ),
+};
+
+/** Pinger data transfer interface descriptor */
+static struct interface_descriptor pinger_xfer_desc =
+	INTF_DESC ( struct pinger, xfer, pinger_xfer_op );
+
+/** Pinger job control interface operations */
+static struct interface_operation pinger_job_op[] = {
+	INTF_OP ( intf_close, struct pinger *, pinger_close ),
+};
+
+/** Pinger job control interface descriptor */
+static struct interface_descriptor pinger_job_desc =
+	INTF_DESC ( struct pinger, job, pinger_job_op );
+
+/**
+ * Create pinger
+ *
+ * @v job		Job control interface
+ * @v hostname		Hostname to ping
+ * @v timeout		Timeout (in ticks)
+ * @v len		Payload length
+ * @ret rc		Return status code
+ */
+int create_pinger ( struct interface *job, const char *hostname,
+		    unsigned long timeout, size_t len,
+		    void ( * callback ) ( struct sockaddr *src,
+					  unsigned int sequence, size_t len,
+					  int rc ) ) {
+	struct pinger *pinger;
+	int rc;
+
+	/* Sanity check */
+	if ( ! timeout )
+		return -EINVAL;
+
+	/* Allocate and initialise structure */
+	pinger = zalloc ( sizeof ( *pinger ) );
+	if ( ! pinger )
+		return -ENOMEM;
+	ref_init ( &pinger->refcnt, NULL );
+	intf_init ( &pinger->job, &pinger_job_desc, &pinger->refcnt );
+	intf_init ( &pinger->xfer, &pinger_xfer_desc, &pinger->refcnt );
+	timer_init ( &pinger->timer, pinger_expired, &pinger->refcnt );
+	pinger->timeout = timeout;
+	pinger->len = len;
+	pinger->callback = callback;
+
+	/* Open socket */
+	if ( ( rc = xfer_open_named_socket ( &pinger->xfer, SOCK_ECHO, NULL,
+					     hostname, NULL ) ) != 0 ) {
+		DBGC ( pinger, "PINGER %p could not open socket: %s\n",
+		       pinger, strerror ( rc ) );
+		goto err;
+	}
+
+	/* Attach parent interface, mortalise self, and return */
+	intf_plug_plug ( &pinger->job, job );
+	ref_put ( &pinger->refcnt );
+	return 0;
+
+ err:
+	pinger_close ( pinger, rc );
+	ref_put ( &pinger->refcnt );
+	return rc;
+}

src/include/ipxe/errfile.h

@@ -64,6 +64,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_xferbuf		       ( ERRFILE_CORE | 0x00180000 )
 #define ERRFILE_pending		       ( ERRFILE_CORE | 0x00190000 )
 #define ERRFILE_null_reboot	       ( ERRFILE_CORE | 0x001a0000 )
+#define ERRFILE_pinger		       ( ERRFILE_CORE | 0x001b0000 )
 
 #define ERRFILE_eisa		     ( ERRFILE_DRIVER | 0x00000000 )
 #define ERRFILE_isa		     ( ERRFILE_DRIVER | 0x00010000 )

src/include/ipxe/pinger.h

@@ -0,0 +1,23 @@
+#ifndef _IPXE_PINGER_H
+#define _IPXE_PINGER_H
+
+/** @file
+ *
+ * ICMP ping sender
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <ipxe/interface.h>
+#include <ipxe/socket.h>
+
+extern int create_pinger ( struct interface *job, const char *hostname,
+			   unsigned long timeout, size_t len,
+			   void ( * callback ) ( struct sockaddr *peer,
+						 unsigned int sequence,
+						 size_t len,
+						 int rc ) );
+
+#endif /* _IPXE_PINGER_H */