Adding debian version 2.06-13+deb12u1.debian/2.06-13+deb12u1debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 2588 insertions, 0 deletions

diff --git a/debian/grub-extras/disabled/gpxe/src/net/tcp/http.c b/debian/grub-extras/disabled/gpxe/src/net/tcp/http.c
new file mode 100644
index 0000000..a02408a
--- /dev/null
+++ b/debian/grub-extras/disabled/gpxe/src/net/tcp/http.c
@@ -0,0 +1,603 @@
+/*
+ * Copyright (C) 2007 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * Hyper Text Transfer Protocol (HTTP)
+ *
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <strings.h>
+#include <byteswap.h>
+#include <errno.h>
+#include <assert.h>
+#include <gpxe/uri.h>
+#include <gpxe/refcnt.h>
+#include <gpxe/iobuf.h>
+#include <gpxe/xfer.h>
+#include <gpxe/open.h>
+#include <gpxe/socket.h>
+#include <gpxe/tcpip.h>
+#include <gpxe/process.h>
+#include <gpxe/linebuf.h>
+#include <gpxe/features.h>
+#include <gpxe/base64.h>
+#include <gpxe/http.h>
+
+FEATURE ( FEATURE_PROTOCOL, "HTTP", DHCP_EB_FEATURE_HTTP, 1 );
+
+/** HTTP receive state */
+enum http_rx_state {
+	HTTP_RX_RESPONSE = 0,
+	HTTP_RX_HEADER,
+	HTTP_RX_DATA,
+	HTTP_RX_DEAD,
+};
+
+/**
+ * An HTTP request
+ *
+ */
+struct http_request {
+	/** Reference count */
+	struct refcnt refcnt;
+	/** Data transfer interface */
+	struct xfer_interface xfer;
+
+	/** URI being fetched */
+	struct uri *uri;
+	/** Transport layer interface */
+	struct xfer_interface socket;
+
+	/** TX process */
+	struct process process;
+
+	/** HTTP response code */
+	unsigned int response;
+	/** HTTP Content-Length */
+	size_t content_length;
+	/** Received length */
+	size_t rx_len;
+	/** RX state */
+	enum http_rx_state rx_state;
+	/** Line buffer for received header lines */
+	struct line_buffer linebuf;
+};
+
+/**
+ * Free HTTP request
+ *
+ * @v refcnt		Reference counter
+ */
+static void http_free ( struct refcnt *refcnt ) {
+	struct http_request *http =
+		container_of ( refcnt, struct http_request, refcnt );
+
+	uri_put ( http->uri );
+	empty_line_buffer ( &http->linebuf );
+	free ( http );
+};
+
+/**
+ * Mark HTTP request as complete
+ *
+ * @v http		HTTP request
+ * @v rc		Return status code
+ */
+static void http_done ( struct http_request *http, int rc ) {
+
+	/* Prevent further processing of any current packet */
+	http->rx_state = HTTP_RX_DEAD;
+
+	/* If we had a Content-Length, and the received content length
+	 * isn't correct, flag an error
+	 */
+	if ( http->content_length &&
+	     ( http->content_length != http->rx_len ) ) {
+		DBGC ( http, "HTTP %p incorrect length %zd, should be %zd\n",
+		       http, http->rx_len, http->content_length );
+		rc = -EIO;
+	}
+
+	/* Remove process */
+	process_del ( &http->process );
+
+	/* Close all data transfer interfaces */
+	xfer_nullify ( &http->socket );
+	xfer_close ( &http->socket, rc );
+	xfer_nullify ( &http->xfer );
+	xfer_close ( &http->xfer, rc );
+}
+
+/**
+ * Convert HTTP response code to return status code
+ *
+ * @v response		HTTP response code
+ * @ret rc		Return status code
+ */
+static int http_response_to_rc ( unsigned int response ) {
+	switch ( response ) {
+	case 200:
+	case 301:
+	case 302:
+		return 0;
+	case 404:
+		return -ENOENT;
+	case 403:
+		return -EPERM;
+	case 401:
+		return -EACCES;
+	default:
+		return -EIO;
+	}
+}
+
+/**
+ * Handle HTTP response
+ *
+ * @v http		HTTP request
+ * @v response		HTTP response
+ * @ret rc		Return status code
+ */
+static int http_rx_response ( struct http_request *http, char *response ) {
+	char *spc;
+	int rc;
+
+	DBGC ( http, "HTTP %p response \"%s\"\n", http, response );
+
+	/* Check response starts with "HTTP/" */
+	if ( strncmp ( response, "HTTP/", 5 ) != 0 )
+		return -EIO;
+
+	/* Locate and check response code */
+	spc = strchr ( response, ' ' );
+	if ( ! spc )
+		return -EIO;
+	http->response = strtoul ( spc, NULL, 10 );
+	if ( ( rc = http_response_to_rc ( http->response ) ) != 0 )
+		return rc;
+
+	/* Move to received headers */
+	http->rx_state = HTTP_RX_HEADER;
+	return 0;
+}
+
+/**
+ * Handle HTTP Location header
+ *
+ * @v http		HTTP request
+ * @v value		HTTP header value
+ * @ret rc		Return status code
+ */
+static int http_rx_location ( struct http_request *http, const char *value ) {
+	int rc;
+
+	/* Redirect to new location */
+	DBGC ( http, "HTTP %p redirecting to %s\n", http, value );
+	if ( ( rc = xfer_redirect ( &http->xfer, LOCATION_URI_STRING,
+				    value ) ) != 0 ) {
+		DBGC ( http, "HTTP %p could not redirect: %s\n",
+		       http, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Handle HTTP Content-Length header
+ *
+ * @v http		HTTP request
+ * @v value		HTTP header value
+ * @ret rc		Return status code
+ */
+static int http_rx_content_length ( struct http_request *http,
+				    const char *value ) {
+	char *endp;
+
+	http->content_length = strtoul ( value, &endp, 10 );
+	if ( *endp != '\0' ) {
+		DBGC ( http, "HTTP %p invalid Content-Length \"%s\"\n",
+		       http, value );
+		return -EIO;
+	}
+
+	/* Use seek() to notify recipient of filesize */
+	xfer_seek ( &http->xfer, http->content_length, SEEK_SET );
+	xfer_seek ( &http->xfer, 0, SEEK_SET );
+
+	return 0;
+}
+
+/** An HTTP header handler */
+struct http_header_handler {
+	/** Name (e.g. "Content-Length") */
+	const char *header;
+	/** Handle received header
+	 *
+	 * @v http	HTTP request
+	 * @v value	HTTP header value
+	 * @ret rc	Return status code
+	 *
+	 * If an error is returned, the download will be aborted.
+	 */
+	int ( * rx ) ( struct http_request *http, const char *value );
+};
+
+/** List of HTTP header handlers */
+static struct http_header_handler http_header_handlers[] = {
+	{
+		.header = "Location",
+		.rx = http_rx_location,
+	},
+	{
+		.header = "Content-Length",
+		.rx = http_rx_content_length,
+	},
+	{ NULL, NULL }
+};
+
+/**
+ * Handle HTTP header
+ *
+ * @v http		HTTP request
+ * @v header		HTTP header
+ * @ret rc		Return status code
+ */
+static int http_rx_header ( struct http_request *http, char *header ) {
+	struct http_header_handler *handler;
+	char *separator;
+	char *value;
+	int rc;
+
+	/* An empty header line marks the transition to the data phase */
+	if ( ! header[0] ) {
+		DBGC ( http, "HTTP %p start of data\n", http );
+		empty_line_buffer ( &http->linebuf );
+		http->rx_state = HTTP_RX_DATA;
+		return 0;
+	}
+
+	DBGC ( http, "HTTP %p header \"%s\"\n", http, header );
+
+	/* Split header at the ": " */
+	separator = strstr ( header, ": " );
+	if ( ! separator ) {
+		DBGC ( http, "HTTP %p malformed header\n", http );
+		return -EIO;
+	}
+	*separator = '\0';
+	value = ( separator + 2 );
+
+	/* Hand off to header handler, if one exists */
+	for ( handler = http_header_handlers ; handler->header ; handler++ ) {
+		if ( strcasecmp ( header, handler->header ) == 0 ) {
+			if ( ( rc = handler->rx ( http, value ) ) != 0 )
+				return rc;
+			break;
+		}
+	}
+	return 0;
+}
+
+/** An HTTP line-based data handler */
+struct http_line_handler {
+	/** Handle line
+	 *
+	 * @v http	HTTP request
+	 * @v line	Line to handle
+	 * @ret rc	Return status code
+	 */
+	int ( * rx ) ( struct http_request *http, char *line );
+};
+
+/** List of HTTP line-based data handlers */
+static struct http_line_handler http_line_handlers[] = {
+	[HTTP_RX_RESPONSE]	= { .rx = http_rx_response },
+	[HTTP_RX_HEADER]	= { .rx = http_rx_header },
+};
+
+/**
+ * Handle new data arriving via HTTP connection in the data phase
+ *
+ * @v http		HTTP request
+ * @v iobuf		I/O buffer
+ * @ret rc		Return status code
+ */
+static int http_rx_data ( struct http_request *http,
+			  struct io_buffer *iobuf ) {
+	int rc;
+
+	/* Update received length */
+	http->rx_len += iob_len ( iobuf );
+
+	/* Hand off data buffer */
+	if ( ( rc = xfer_deliver_iob ( &http->xfer, iobuf ) ) != 0 )
+		return rc;
+
+	/* If we have reached the content-length, stop now */
+	if ( http->content_length &&
+	     ( http->rx_len >= http->content_length ) ) {
+		http_done ( http, 0 );
+	}
+
+	return 0;
+}
+
+/**
+ * Handle new data arriving via HTTP connection
+ *
+ * @v socket		Transport layer interface
+ * @v iobuf		I/O buffer
+ * @v meta		Data transfer metadata
+ * @ret rc		Return status code
+ */
+static int http_socket_deliver_iob ( struct xfer_interface *socket,
+				     struct io_buffer *iobuf,
+				     struct xfer_metadata *meta __unused ) {
+	struct http_request *http =
+		container_of ( socket, struct http_request, socket );
+	struct http_line_handler *lh;
+	char *line;
+	ssize_t len;
+	int rc = 0;
+
+	while ( iob_len ( iobuf ) ) {
+		switch ( http->rx_state ) {
+		case HTTP_RX_DEAD:
+			/* Do no further processing */
+			goto done;
+		case HTTP_RX_DATA:
+			/* Once we're into the data phase, just fill
+			 * the data buffer
+			 */
+			rc = http_rx_data ( http, iob_disown ( iobuf ) );
+			goto done;
+		case HTTP_RX_RESPONSE:
+		case HTTP_RX_HEADER:
+			/* In the other phases, buffer and process a
+			 * line at a time
+			 */
+			len = line_buffer ( &http->linebuf, iobuf->data,
+					    iob_len ( iobuf ) );
+			if ( len < 0 ) {
+				rc = len;
+				DBGC ( http, "HTTP %p could not buffer line: "
+				       "%s\n", http, strerror ( rc ) );
+				goto done;
+			}
+			iob_pull ( iobuf, len );
+			line = buffered_line ( &http->linebuf );
+			if ( line ) {
+				lh = &http_line_handlers[http->rx_state];
+				if ( ( rc = lh->rx ( http, line ) ) != 0 )
+					goto done;
+			}
+			break;
+		default:
+			assert ( 0 );
+			break;
+		}
+	}
+
+ done:
+	if ( rc )
+		http_done ( http, rc );
+	free_iob ( iobuf );
+	return rc;
+}
+
+/**
+ * HTTP process
+ *
+ * @v process		Process
+ */
+static void http_step ( struct process *process ) {
+	struct http_request *http =
+		container_of ( process, struct http_request, process );
+	const char *path = http->uri->path;
+	const char *host = http->uri->host;
+	const char *query = http->uri->query;
+	const char *user = http->uri->user;
+	const char *password =
+		( http->uri->password ? http->uri->password : "" );
+	size_t user_pw_len = ( user ? ( strlen ( user ) + 1 /* ":" */ +
+					strlen ( password ) ) : 0 );
+	size_t user_pw_base64_len = base64_encoded_len ( user_pw_len );
+	char user_pw[ user_pw_len + 1 /* NUL */ ];
+	char user_pw_base64[ user_pw_base64_len + 1 /* NUL */ ];
+	int rc;
+
+	if ( xfer_window ( &http->socket ) ) {
+
+		/* We want to execute only once */
+		process_del ( &http->process );
+
+		/* Construct authorisation, if applicable */
+		if ( user ) {
+			char *buf = user_pw;
+			ssize_t remaining = sizeof ( user_pw );
+			size_t len;
+
+			/* URI-decode the username and password */
+			len = uri_decode ( user, buf, remaining );
+			buf += len;
+			remaining -= len;
+			*(remaining--, buf++) = ':';
+			len = uri_decode ( password, buf, remaining );
+			buf += len;
+			remaining -= len;
+			assert ( remaining >= 0 );
+
+			/* Base64-encode the "user:password" string */
+			base64_encode ( user_pw, user_pw_base64 );
+		}
+
+		/* Send GET request */
+		if ( ( rc = xfer_printf ( &http->socket,
+					  "GET %s%s%s HTTP/1.0\r\n"
+					  "User-Agent: gPXE/" VERSION "\r\n"
+					  "%s%s%s"
+					  "Host: %s\r\n"
+					  "\r\n",
+					  ( path ? path : "/" ),
+					  ( query ? "?" : "" ),
+					  ( query ? query : "" ),
+					  ( user ?
+					    "Authorization: Basic " : "" ),
+					  ( user ? user_pw_base64 : "" ),
+					  ( user ? "\r\n" : "" ),
+					  host ) ) != 0 ) {
+			http_done ( http, rc );
+		}
+	}
+}
+
+/**
+ * HTTP connection closed by network stack
+ *
+ * @v socket		Transport layer interface
+ * @v rc		Reason for close
+ */
+static void http_socket_close ( struct xfer_interface *socket, int rc ) {
+	struct http_request *http =
+		container_of ( socket, struct http_request, socket );
+
+	DBGC ( http, "HTTP %p socket closed: %s\n",
+	       http, strerror ( rc ) );
+	
+	http_done ( http, rc );
+}
+
+/** HTTP socket operations */
+static struct xfer_interface_operations http_socket_operations = {
+	.close		= http_socket_close,
+	.vredirect	= xfer_vreopen,
+	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
+	.deliver_iob	= http_socket_deliver_iob,
+	.deliver_raw	= xfer_deliver_as_iob,
+};
+
+/**
+ * Close HTTP data transfer interface
+ *
+ * @v xfer		Data transfer interface
+ * @v rc		Reason for close
+ */
+static void http_xfer_close ( struct xfer_interface *xfer, int rc ) {
+	struct http_request *http =
+		container_of ( xfer, struct http_request, xfer );
+
+	DBGC ( http, "HTTP %p interface closed: %s\n",
+	       http, strerror ( rc ) );
+
+	http_done ( http, rc );
+}
+
+/** HTTP data transfer interface operations */
+static struct xfer_interface_operations http_xfer_operations = {
+	.close		= http_xfer_close,
+	.vredirect	= ignore_xfer_vredirect,
+	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
+	.deliver_iob	= xfer_deliver_as_raw,
+	.deliver_raw	= ignore_xfer_deliver_raw,
+};
+
+/**
+ * Initiate an HTTP connection, with optional filter
+ *
+ * @v xfer		Data transfer interface
+ * @v uri		Uniform Resource Identifier
+ * @v default_port	Default port number
+ * @v filter		Filter to apply to socket, or NULL
+ * @ret rc		Return status code
+ */
+int http_open_filter ( struct xfer_interface *xfer, struct uri *uri,
+		       unsigned int default_port,
+		       int ( * filter ) ( struct xfer_interface *xfer,
+					  struct xfer_interface **next ) ) {
+	struct http_request *http;
+	struct sockaddr_tcpip server;
+	struct xfer_interface *socket;
+	int rc;
+
+	/* Sanity checks */
+	if ( ! uri->host )
+		return -EINVAL;
+
+	/* Allocate and populate HTTP structure */
+	http = zalloc ( sizeof ( *http ) );
+	if ( ! http )
+		return -ENOMEM;
+	http->refcnt.free = http_free;
+	xfer_init ( &http->xfer, &http_xfer_operations, &http->refcnt );
+       	http->uri = uri_get ( uri );
+	xfer_init ( &http->socket, &http_socket_operations, &http->refcnt );
+	process_init ( &http->process, http_step, &http->refcnt );
+
+	/* Open socket */
+	memset ( &server, 0, sizeof ( server ) );
+	server.st_port = htons ( uri_port ( http->uri, default_port ) );
+	socket = &http->socket;
+	if ( filter ) {
+		if ( ( rc = filter ( socket, &socket ) ) != 0 )
+			goto err;
+	}
+	if ( ( rc = xfer_open_named_socket ( socket, SOCK_STREAM,
+					     ( struct sockaddr * ) &server,
+					     uri->host, NULL ) ) != 0 )
+		goto err;
+
+	/* Attach to parent interface, mortalise self, and return */
+	xfer_plug_plug ( &http->xfer, xfer );
+	ref_put ( &http->refcnt );
+	return 0;
+
+ err:
+	DBGC ( http, "HTTP %p could not create request: %s\n", 
+	       http, strerror ( rc ) );
+	http_done ( http, rc );
+	ref_put ( &http->refcnt );
+	return rc;
+}
+
+/**
+ * Initiate an HTTP connection
+ *
+ * @v xfer		Data transfer interface
+ * @v uri		Uniform Resource Identifier
+ * @ret rc		Return status code
+ */
+static int http_open ( struct xfer_interface *xfer, struct uri *uri ) {
+	return http_open_filter ( xfer, uri, HTTP_PORT, NULL );
+}
+
+/** HTTP URI opener */
+struct uri_opener http_uri_opener __uri_opener = {
+	.scheme	= "http",
+	.open	= http_open,
+};
diff --git a/debian/grub-extras/disabled/gpxe/src/net/tcp/https.c b/debian/grub-extras/disabled/gpxe/src/net/tcp/https.c
new file mode 100644
index 0000000..7a2961f
--- /dev/null
+++ b/debian/grub-extras/disabled/gpxe/src/net/tcp/https.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2007 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/**
+ * @file
+ *
+ * Secure Hyper Text Transfer Protocol (HTTPS)
+ *
+ */
+
+#include <stddef.h>
+#include <gpxe/open.h>
+#include <gpxe/tls.h>
+#include <gpxe/http.h>
+#include <gpxe/features.h>
+
+FEATURE ( FEATURE_PROTOCOL, "HTTPS", DHCP_EB_FEATURE_HTTPS, 1 );
+
+/**
+ * Initiate an HTTPS connection
+ *
+ * @v xfer		Data transfer interface
+ * @v uri		Uniform Resource Identifier
+ * @ret rc		Return status code
+ */
+static int https_open ( struct xfer_interface *xfer, struct uri *uri ) {
+	return http_open_filter ( xfer, uri, HTTPS_PORT, add_tls );
+}
+
+/** HTTPS URI opener */
+struct uri_opener https_uri_opener __uri_opener = {
+	.scheme	= "https",
+	.open	= https_open,
+};
diff --git a/debian/grub-extras/disabled/gpxe/src/net/tcp/iscsi.c b/debian/grub-extras/disabled/gpxe/src/net/tcp/iscsi.c
new file mode 100644
index 0000000..771384b
--- /dev/null
+++ b/debian/grub-extras/disabled/gpxe/src/net/tcp/iscsi.c
@@ -0,0 +1,1934 @@
+/*
+ * Copyright (C) 2006 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <assert.h>
+#include <byteswap.h>
+#include <gpxe/vsprintf.h>
+#include <gpxe/socket.h>
+#include <gpxe/xfer.h>
+#include <gpxe/open.h>
+#include <gpxe/scsi.h>
+#include <gpxe/process.h>
+#include <gpxe/uaccess.h>
+#include <gpxe/tcpip.h>
+#include <gpxe/settings.h>
+#include <gpxe/features.h>
+#include <gpxe/iscsi.h>
+
+/** @file
+ *
+ * iSCSI protocol
+ *
+ */
+
+FEATURE ( FEATURE_PROTOCOL, "iSCSI", DHCP_EB_FEATURE_ISCSI, 1 );
+
+/** iSCSI initiator name (explicitly specified) */
+static char *iscsi_explicit_initiator_iqn;
+
+/** Default iSCSI initiator name (constructed from hostname) */
+static char *iscsi_default_initiator_iqn;
+
+/** iSCSI initiator username */
+static char *iscsi_initiator_username;
+
+/** iSCSI initiator password */
+static char *iscsi_initiator_password;
+
+/** iSCSI target username */
+static char *iscsi_target_username;
+
+/** iSCSI target password */
+static char *iscsi_target_password;
+
+static void iscsi_start_tx ( struct iscsi_session *iscsi );
+static void iscsi_start_login ( struct iscsi_session *iscsi );
+static void iscsi_start_data_out ( struct iscsi_session *iscsi,
+				   unsigned int datasn );
+
+/**
+ * Finish receiving PDU data into buffer
+ *
+ * @v iscsi		iSCSI session
+ */
+static void iscsi_rx_buffered_data_done ( struct iscsi_session *iscsi ) {
+	free ( iscsi->rx_buffer );
+	iscsi->rx_buffer = NULL;
+}
+
+/**
+ * Free iSCSI session
+ *
+ * @v refcnt		Reference counter
+ */
+static void iscsi_free ( struct refcnt *refcnt ) {
+	struct iscsi_session *iscsi =
+		container_of ( refcnt, struct iscsi_session, refcnt );
+
+	free ( iscsi->target_address );
+	free ( iscsi->target_iqn );
+	free ( iscsi->initiator_username );
+	free ( iscsi->initiator_password );
+	free ( iscsi->target_username );
+	free ( iscsi->target_password );
+	chap_finish ( &iscsi->chap );
+	iscsi_rx_buffered_data_done ( iscsi );
+	free ( iscsi );
+}
+
+/**
+ * Open iSCSI transport-layer connection
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ */
+static int iscsi_open_connection ( struct iscsi_session *iscsi ) {
+	struct sockaddr_tcpip target;
+	int rc;
+
+	assert ( iscsi->tx_state == ISCSI_TX_IDLE );
+	assert ( iscsi->rx_state == ISCSI_RX_BHS );
+	assert ( iscsi->rx_offset == 0 );
+
+	/* Open socket */
+	memset ( &target, 0, sizeof ( target ) );
+	target.st_port = htons ( iscsi->target_port );
+	if ( ( rc = xfer_open_named_socket ( &iscsi->socket, SOCK_STREAM,
+					     ( struct sockaddr * ) &target,
+					     iscsi->target_address,
+					     NULL ) ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p could not open socket: %s\n",
+		       iscsi, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Enter security negotiation phase */
+	iscsi->status = ( ISCSI_STATUS_SECURITY_NEGOTIATION_PHASE |
+			  ISCSI_STATUS_STRINGS_SECURITY );
+	if ( iscsi->target_username )
+		iscsi->status |= ISCSI_STATUS_AUTH_REVERSE_REQUIRED;
+
+	/* Assign fresh initiator task tag */
+	iscsi->itt++;
+
+	/* Initiate login */
+	iscsi_start_login ( iscsi );
+
+	return 0;
+}
+
+/**
+ * Close iSCSI transport-layer connection
+ *
+ * @v iscsi		iSCSI session
+ * @v rc		Reason for close
+ *
+ * Closes the transport-layer connection and resets the session state
+ * ready to attempt a fresh login.
+ */
+static void iscsi_close_connection ( struct iscsi_session *iscsi, int rc ) {
+
+	/* Close all data transfer interfaces */
+	xfer_close ( &iscsi->socket, rc );
+
+	/* Clear connection status */
+	iscsi->status = 0;
+
+	/* Reset TX and RX state machines */
+	iscsi->tx_state = ISCSI_TX_IDLE;
+	iscsi->rx_state = ISCSI_RX_BHS;
+	iscsi->rx_offset = 0;
+
+	/* Free any temporary dynamically allocated memory */
+	chap_finish ( &iscsi->chap );
+	iscsi_rx_buffered_data_done ( iscsi );
+}
+
+/**
+ * Mark iSCSI SCSI operation as complete
+ *
+ * @v iscsi		iSCSI session
+ * @v rc		Return status code
+ *
+ * Note that iscsi_scsi_done() will not close the connection, and must
+ * therefore be called only when the internal state machines are in an
+ * appropriate state, otherwise bad things may happen on the next call
+ * to iscsi_issue().  The general rule is to call iscsi_scsi_done()
+ * only at the end of receiving a PDU; at this point the TX and RX
+ * engines should both be idle.
+ */
+static void iscsi_scsi_done ( struct iscsi_session *iscsi, int rc ) {
+
+	assert ( iscsi->tx_state == ISCSI_TX_IDLE );
+	assert ( iscsi->command != NULL );
+
+	iscsi->command->rc = rc;
+	iscsi->command = NULL;
+}
+
+/****************************************************************************
+ *
+ * iSCSI SCSI command issuing
+ *
+ */
+
+/**
+ * Build iSCSI SCSI command BHS
+ *
+ * @v iscsi		iSCSI session
+ *
+ * We don't currently support bidirectional commands (i.e. with both
+ * Data-In and Data-Out segments); these would require providing code
+ * to generate an AHS, and there doesn't seem to be any need for it at
+ * the moment.
+ */
+static void iscsi_start_command ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_scsi_command *command = &iscsi->tx_bhs.scsi_command;
+
+	assert ( ! ( iscsi->command->data_in && iscsi->command->data_out ) );
+
+	/* Construct BHS and initiate transmission */
+	iscsi_start_tx ( iscsi );
+	command->opcode = ISCSI_OPCODE_SCSI_COMMAND;
+	command->flags = ( ISCSI_FLAG_FINAL |
+			   ISCSI_COMMAND_ATTR_SIMPLE );
+	if ( iscsi->command->data_in )
+		command->flags |= ISCSI_COMMAND_FLAG_READ;
+	if ( iscsi->command->data_out )
+		command->flags |= ISCSI_COMMAND_FLAG_WRITE;
+	/* lengths left as zero */
+	command->lun = iscsi->lun;
+	command->itt = htonl ( ++iscsi->itt );
+	command->exp_len = htonl ( iscsi->command->data_in_len |
+				   iscsi->command->data_out_len );
+	command->cmdsn = htonl ( iscsi->cmdsn );
+	command->expstatsn = htonl ( iscsi->statsn + 1 );
+	memcpy ( &command->cdb, &iscsi->command->cdb, sizeof ( command->cdb ));
+	DBGC2 ( iscsi, "iSCSI %p start " SCSI_CDB_FORMAT " %s %#zx\n",
+		iscsi, SCSI_CDB_DATA ( command->cdb ),
+		( iscsi->command->data_in ? "in" : "out" ),
+		( iscsi->command->data_in ?
+		  iscsi->command->data_in_len :
+		  iscsi->command->data_out_len ) );
+}
+
+/**
+ * Receive data segment of an iSCSI SCSI response PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ */
+static int iscsi_rx_scsi_response ( struct iscsi_session *iscsi,
+				    const void *data, size_t len,
+				    size_t remaining ) {
+	struct iscsi_bhs_scsi_response *response
+		= &iscsi->rx_bhs.scsi_response;
+	int sense_offset;
+
+	/* Capture the sense response code as it floats past, if present */
+	sense_offset = ISCSI_SENSE_RESPONSE_CODE_OFFSET - iscsi->rx_offset;
+	if ( ( sense_offset >= 0 ) && len ) {
+		iscsi->command->sense_response =
+			* ( ( char * ) data + sense_offset );
+	}
+
+	/* Wait for whole SCSI response to arrive */
+	if ( remaining )
+		return 0;
+	
+	/* Record SCSI status code */
+	iscsi->command->status = response->status;
+
+	/* Check for errors */
+	if ( response->response != ISCSI_RESPONSE_COMMAND_COMPLETE )
+		return -EIO;
+
+	/* Mark as completed */
+	iscsi_scsi_done ( iscsi, 0 );
+	return 0;
+}
+
+/**
+ * Receive data segment of an iSCSI data-in PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ */
+static int iscsi_rx_data_in ( struct iscsi_session *iscsi,
+			      const void *data, size_t len,
+			      size_t remaining ) {
+	struct iscsi_bhs_data_in *data_in = &iscsi->rx_bhs.data_in;
+	unsigned long offset;
+
+	/* Copy data to data-in buffer */
+	offset = ntohl ( data_in->offset ) + iscsi->rx_offset;
+	assert ( iscsi->command != NULL );
+	assert ( iscsi->command->data_in );
+	assert ( ( offset + len ) <= iscsi->command->data_in_len );
+	copy_to_user ( iscsi->command->data_in, offset, data, len );
+
+	/* Wait for whole SCSI response to arrive */
+	if ( remaining )
+		return 0;
+
+	/* Mark as completed if status is present */
+	if ( data_in->flags & ISCSI_DATA_FLAG_STATUS ) {
+		assert ( ( offset + len ) == iscsi->command->data_in_len );
+		assert ( data_in->flags & ISCSI_FLAG_FINAL );
+		iscsi->command->status = data_in->status;
+		/* iSCSI cannot return an error status via a data-in */
+		iscsi_scsi_done ( iscsi, 0 );
+	}
+
+	return 0;
+}
+
+/**
+ * Receive data segment of an iSCSI R2T PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ */
+static int iscsi_rx_r2t ( struct iscsi_session *iscsi,
+			  const void *data __unused, size_t len __unused,
+			  size_t remaining __unused ) {
+	struct iscsi_bhs_r2t *r2t = &iscsi->rx_bhs.r2t;
+
+	/* Record transfer parameters and trigger first data-out */
+	iscsi->ttt = ntohl ( r2t->ttt );
+	iscsi->transfer_offset = ntohl ( r2t->offset );
+	iscsi->transfer_len = ntohl ( r2t->len );
+	iscsi_start_data_out ( iscsi, 0 );
+
+	return 0;
+}
+
+/**
+ * Build iSCSI data-out BHS
+ *
+ * @v iscsi		iSCSI session
+ * @v datasn		Data sequence number within the transfer
+ *
+ */
+static void iscsi_start_data_out ( struct iscsi_session *iscsi,
+				   unsigned int datasn ) {
+	struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
+	unsigned long offset;
+	unsigned long remaining;
+	unsigned long len;
+
+	/* We always send 512-byte Data-Out PDUs; this removes the
+	 * need to worry about the target's MaxRecvDataSegmentLength.
+	 */
+	offset = datasn * 512;
+	remaining = iscsi->transfer_len - offset;
+	len = remaining;
+	if ( len > 512 )
+		len = 512;
+
+	/* Construct BHS and initiate transmission */
+	iscsi_start_tx ( iscsi );
+	data_out->opcode = ISCSI_OPCODE_DATA_OUT;
+	if ( len == remaining )
+		data_out->flags = ( ISCSI_FLAG_FINAL );
+	ISCSI_SET_LENGTHS ( data_out->lengths, 0, len );
+	data_out->lun = iscsi->lun;
+	data_out->itt = htonl ( iscsi->itt );
+	data_out->ttt = htonl ( iscsi->ttt );
+	data_out->expstatsn = htonl ( iscsi->statsn + 1 );
+	data_out->datasn = htonl ( datasn );
+	data_out->offset = htonl ( iscsi->transfer_offset + offset );
+	DBGC ( iscsi, "iSCSI %p start data out DataSN %#x len %#lx\n",
+	       iscsi, datasn, len );
+}
+
+/**
+ * Complete iSCSI data-out PDU transmission
+ *
+ * @v iscsi		iSCSI session
+ *
+ */
+static void iscsi_data_out_done ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
+
+	/* If we haven't reached the end of the sequence, start
+	 * sending the next data-out PDU.
+	 */
+	if ( ! ( data_out->flags & ISCSI_FLAG_FINAL ) )
+		iscsi_start_data_out ( iscsi, ntohl ( data_out->datasn ) + 1 );
+}
+
+/**
+ * Send iSCSI data-out data segment
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ */
+static int iscsi_tx_data_out ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_data_out *data_out = &iscsi->tx_bhs.data_out;
+	struct io_buffer *iobuf;
+	unsigned long offset;
+	size_t len;
+
+	offset = ntohl ( data_out->offset );
+	len = ISCSI_DATA_LEN ( data_out->lengths );
+
+	assert ( iscsi->command != NULL );
+	assert ( iscsi->command->data_out );
+	assert ( ( offset + len ) <= iscsi->command->data_out_len );
+
+	iobuf = xfer_alloc_iob ( &iscsi->socket, len );
+	if ( ! iobuf )
+		return -ENOMEM;
+	
+	copy_from_user ( iob_put ( iobuf, len ),
+			 iscsi->command->data_out, offset, len );
+
+	return xfer_deliver_iob ( &iscsi->socket, iobuf );
+}
+
+/****************************************************************************
+ *
+ * iSCSI login
+ *
+ */
+
+/**
+ * Build iSCSI login request strings
+ *
+ * @v iscsi		iSCSI session
+ *
+ * These are the initial set of strings sent in the first login
+ * request PDU.  We want the following settings:
+ *
+ *     HeaderDigest=None
+ *     DataDigest=None
+ *     MaxConnections is irrelevant; we make only one connection anyway
+ *     InitialR2T=Yes [1]
+ *     ImmediateData is irrelevant; we never send immediate data
+ *     MaxRecvDataSegmentLength=8192 (default; we don't care) [3]
+ *     MaxBurstLength=262144 (default; we don't care) [3]
+ *     FirstBurstLength=262144 (default; we don't care)
+ *     DefaultTime2Wait=0 [2]
+ *     DefaultTime2Retain=0 [2]
+ *     MaxOutstandingR2T=1
+ *     DataPDUInOrder=Yes
+ *     DataSequenceInOrder=Yes
+ *     ErrorRecoveryLevel=0
+ *
+ * [1] InitialR2T has an OR resolution function, so the target may
+ * force us to use it.  We therefore simplify our logic by always
+ * using it.
+ *
+ * [2] These ensure that we can safely start a new task once we have
+ * reconnected after a failure, without having to manually tidy up
+ * after the old one.
+ *
+ * [3] We are quite happy to use the RFC-defined default values for
+ * these parameters, but some targets (notably OpenSolaris)
+ * incorrectly assume a default value of zero, so we explicitly
+ * specify the default values.
+ */
+static int iscsi_build_login_request_strings ( struct iscsi_session *iscsi,
+					       void *data, size_t len ) {
+	unsigned int used = 0;
+	unsigned int i;
+	const char *auth_method;
+
+	if ( iscsi->status & ISCSI_STATUS_STRINGS_SECURITY ) {
+		/* Default to allowing no authentication */
+		auth_method = "None";
+		/* If we have a credential to supply, permit CHAP */
+		if ( iscsi->initiator_username )
+			auth_method = "CHAP,None";
+		/* If we have a credential to check, force CHAP */
+		if ( iscsi->target_username )
+			auth_method = "CHAP";
+		used += ssnprintf ( data + used, len - used,
+				    "InitiatorName=%s%c"
+				    "TargetName=%s%c"
+				    "SessionType=Normal%c"
+				    "AuthMethod=%s%c",
+				    iscsi_initiator_iqn(), 0,
+				    iscsi->target_iqn, 0, 0,
+				    auth_method, 0 );
+	}
+
+	if ( iscsi->status & ISCSI_STATUS_STRINGS_CHAP_ALGORITHM ) {
+		used += ssnprintf ( data + used, len - used, "CHAP_A=5%c", 0 );
+	}
+	
+	if ( ( iscsi->status & ISCSI_STATUS_STRINGS_CHAP_RESPONSE ) ) {
+		assert ( iscsi->initiator_username != NULL );
+		used += ssnprintf ( data + used, len - used,
+				    "CHAP_N=%s%cCHAP_R=0x",
+				    iscsi->initiator_username, 0 );
+		for ( i = 0 ; i < iscsi->chap.response_len ; i++ ) {
+			used += ssnprintf ( data + used, len - used, "%02x",
+					    iscsi->chap.response[i] );
+		}
+		used += ssnprintf ( data + used, len - used, "%c", 0 );
+	}
+
+	if ( ( iscsi->status & ISCSI_STATUS_STRINGS_CHAP_CHALLENGE ) ) {
+		used += ssnprintf ( data + used, len - used,
+				    "CHAP_I=%d%cCHAP_C=0x",
+				    iscsi->chap_challenge[0], 0 );
+		for ( i = 1 ; i < sizeof ( iscsi->chap_challenge ) ; i++ ) {
+			used += ssnprintf ( data + used, len - used, "%02x",
+					    iscsi->chap_challenge[i] );
+		}
+		used += ssnprintf ( data + used, len - used, "%c", 0 );
+	}
+
+	if ( iscsi->status & ISCSI_STATUS_STRINGS_OPERATIONAL ) {
+		used += ssnprintf ( data + used, len - used,
+				    "HeaderDigest=None%c"
+				    "DataDigest=None%c"
+				    "InitialR2T=Yes%c"
+				    "MaxRecvDataSegmentLength=8192%c"
+				    "MaxBurstLength=262144%c"
+				    "DefaultTime2Wait=0%c"
+				    "DefaultTime2Retain=0%c"
+				    "MaxOutstandingR2T=1%c"
+				    "DataPDUInOrder=Yes%c"
+				    "DataSequenceInOrder=Yes%c"
+				    "ErrorRecoveryLevel=0%c",
+				    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 );
+	}
+
+	return used;
+}
+
+/**
+ * Build iSCSI login request BHS
+ *
+ * @v iscsi		iSCSI session
+ */
+static void iscsi_start_login ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_login_request *request = &iscsi->tx_bhs.login_request;
+	int len;
+
+	/* Construct BHS and initiate transmission */
+	iscsi_start_tx ( iscsi );
+	request->opcode = ( ISCSI_OPCODE_LOGIN_REQUEST |
+			    ISCSI_FLAG_IMMEDIATE );
+	request->flags = ( ( iscsi->status & ISCSI_STATUS_PHASE_MASK ) |
+			   ISCSI_LOGIN_FLAG_TRANSITION );
+	/* version_max and version_min left as zero */
+	len = iscsi_build_login_request_strings ( iscsi, NULL, 0 );
+	ISCSI_SET_LENGTHS ( request->lengths, 0, len );
+	request->isid_iana_en = htonl ( ISCSI_ISID_IANA |
+					IANA_EN_FEN_SYSTEMS );
+	/* isid_iana_qual left as zero */
+	request->tsih = htons ( iscsi->tsih );
+	request->itt = htonl ( iscsi->itt );
+	/* cid left as zero */
+	request->cmdsn = htonl ( iscsi->cmdsn );
+	request->expstatsn = htonl ( iscsi->statsn + 1 );
+}
+
+/**
+ * Complete iSCSI login request PDU transmission
+ *
+ * @v iscsi		iSCSI session
+ *
+ */
+static void iscsi_login_request_done ( struct iscsi_session *iscsi ) {
+
+	/* Clear any "strings to send" flags */
+	iscsi->status &= ~ISCSI_STATUS_STRINGS_MASK;
+
+	/* Free any dynamically allocated storage used for login */
+	chap_finish ( &iscsi->chap );
+}
+
+/**
+ * Transmit data segment of an iSCSI login request PDU
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ *
+ * For login requests, the data segment consists of the login strings.
+ */
+static int iscsi_tx_login_request ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_login_request *request = &iscsi->tx_bhs.login_request;
+	struct io_buffer *iobuf;
+	size_t len;
+
+	len = ISCSI_DATA_LEN ( request->lengths );
+	iobuf = xfer_alloc_iob ( &iscsi->socket, len );
+	if ( ! iobuf )
+		return -ENOMEM;
+	iob_put ( iobuf, len );
+	iscsi_build_login_request_strings ( iscsi, iobuf->data, len );
+	return xfer_deliver_iob ( &iscsi->socket, iobuf );
+}
+
+/**
+ * Handle iSCSI TargetAddress text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		TargetAddress value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_targetaddress_value ( struct iscsi_session *iscsi,
+					      const char *value ) {
+	char *separator;
+
+	DBGC ( iscsi, "iSCSI %p will redirect to %s\n", iscsi, value );
+
+	/* Replace target address */
+	free ( iscsi->target_address );
+	iscsi->target_address = strdup ( value );
+	if ( ! iscsi->target_address )
+		return -ENOMEM;
+
+	/* Replace target port */
+	iscsi->target_port = htons ( ISCSI_PORT );
+	separator = strchr ( iscsi->target_address, ':' );
+	if ( separator ) {
+		*separator = '\0';
+		iscsi->target_port = strtoul ( ( separator + 1 ), NULL, 0 );
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI AuthMethod text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		AuthMethod value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_authmethod_value ( struct iscsi_session *iscsi,
+					   const char *value ) {
+
+	/* If server requests CHAP, send the CHAP_A string */
+	if ( strcmp ( value, "CHAP" ) == 0 ) {
+		DBGC ( iscsi, "iSCSI %p initiating CHAP authentication\n",
+		       iscsi );
+		iscsi->status |= ( ISCSI_STATUS_STRINGS_CHAP_ALGORITHM |
+				   ISCSI_STATUS_AUTH_FORWARD_REQUIRED );
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI CHAP_A text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		CHAP_A value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_chap_a_value ( struct iscsi_session *iscsi,
+				       const char *value ) {
+
+	/* We only ever offer "5" (i.e. MD5) as an algorithm, so if
+	 * the server responds with anything else it is a protocol
+	 * violation.
+	 */
+	if ( strcmp ( value, "5" ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p got invalid CHAP algorithm \"%s\"\n",
+		       iscsi, value );
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI CHAP_I text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		CHAP_I value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_chap_i_value ( struct iscsi_session *iscsi,
+				       const char *value ) {
+	unsigned int identifier;
+	char *endp;
+	int rc;
+
+	/* The CHAP identifier is an integer value */
+	identifier = strtoul ( value, &endp, 0 );
+	if ( *endp != '\0' ) {
+		DBGC ( iscsi, "iSCSI %p saw invalid CHAP identifier \"%s\"\n",
+		       iscsi, value );
+		return -EPROTO;
+	}
+
+	/* Prepare for CHAP with MD5 */
+	chap_finish ( &iscsi->chap );
+	if ( ( rc = chap_init ( &iscsi->chap, &md5_algorithm ) ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p could not initialise CHAP: %s\n",
+		       iscsi, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Identifier and secret are the first two components of the
+	 * challenge.
+	 */
+	chap_set_identifier ( &iscsi->chap, identifier );
+	if ( iscsi->initiator_password ) {
+		chap_update ( &iscsi->chap, iscsi->initiator_password,
+			      strlen ( iscsi->initiator_password ) );
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI CHAP_C text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		CHAP_C value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_chap_c_value ( struct iscsi_session *iscsi,
+				       const char *value ) {
+	char buf[3];
+	char *endp;
+	uint8_t byte;
+	unsigned int i;
+
+	/* Check and strip leading "0x" */
+	if ( ( value[0] != '0' ) || ( value[1] != 'x' ) ) {
+		DBGC ( iscsi, "iSCSI %p saw invalid CHAP challenge \"%s\"\n",
+		       iscsi, value );
+		return -EPROTO;
+	}
+	value += 2;
+
+	/* Process challenge an octet at a time */
+	for ( ; ( value[0] && value[1] ) ; value += 2 ) {
+		memcpy ( buf, value, 2 );
+		buf[2] = 0;
+		byte = strtoul ( buf, &endp, 16 );
+		if ( *endp != '\0' ) {
+			DBGC ( iscsi, "iSCSI %p saw invalid CHAP challenge "
+			       "byte \"%s\"\n", iscsi, buf );
+			return -EPROTO;
+		}
+		chap_update ( &iscsi->chap, &byte, sizeof ( byte ) );
+	}
+
+	/* Build CHAP response */
+	DBGC ( iscsi, "iSCSI %p sending CHAP response\n", iscsi );
+	chap_respond ( &iscsi->chap );
+	iscsi->status |= ISCSI_STATUS_STRINGS_CHAP_RESPONSE;
+
+	/* Send CHAP challenge, if applicable */
+	if ( iscsi->target_username ) {
+		iscsi->status |= ISCSI_STATUS_STRINGS_CHAP_CHALLENGE;
+		/* Generate CHAP challenge data */
+		for ( i = 0 ; i < sizeof ( iscsi->chap_challenge ) ; i++ ) {
+			iscsi->chap_challenge[i] = random();
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI CHAP_N text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		CHAP_N value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_chap_n_value ( struct iscsi_session *iscsi,
+				       const char *value ) {
+
+	/* The target username isn't actually involved at any point in
+	 * the authentication process; it merely serves to identify
+	 * which password the target is using to generate the CHAP
+	 * response.  We unnecessarily verify that the username is as
+	 * expected, in order to provide mildly helpful diagnostics if
+	 * the target is supplying the wrong username/password
+	 * combination.
+	 */
+	if ( iscsi->target_username &&
+	     ( strcmp ( iscsi->target_username, value ) != 0 ) ) {
+		DBGC ( iscsi, "iSCSI %p target username \"%s\" incorrect "
+		       "(wanted \"%s\")\n",
+		       iscsi, value, iscsi->target_username );
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+/**
+ * Handle iSCSI CHAP_R text value
+ *
+ * @v iscsi		iSCSI session
+ * @v value		CHAP_R value
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_chap_r_value ( struct iscsi_session *iscsi,
+				       const char *value ) {
+	char buf[3];
+	char *endp;
+	uint8_t byte;
+	unsigned int i;
+	int rc;
+
+	/* Generate CHAP response for verification */
+	chap_finish ( &iscsi->chap );
+	if ( ( rc = chap_init ( &iscsi->chap, &md5_algorithm ) ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p could not initialise CHAP: %s\n",
+		       iscsi, strerror ( rc ) );
+		return rc;
+	}
+	chap_set_identifier ( &iscsi->chap, iscsi->chap_challenge[0] );
+	if ( iscsi->target_password ) {
+		chap_update ( &iscsi->chap, iscsi->target_password,
+			      strlen ( iscsi->target_password ) );
+	}
+	chap_update ( &iscsi->chap, &iscsi->chap_challenge[1],
+		      ( sizeof ( iscsi->chap_challenge ) - 1 ) );
+	chap_respond ( &iscsi->chap );
+
+	/* Check and strip leading "0x" */
+	if ( ( value[0] != '0' ) || ( value[1] != 'x' ) ) {
+		DBGC ( iscsi, "iSCSI %p saw invalid CHAP response \"%s\"\n",
+		       iscsi, value );
+		return -EPROTO;
+	}
+	value += 2;
+
+	/* Check CHAP response length */
+	if ( strlen ( value ) != ( 2 * iscsi->chap.response_len ) ) {
+		DBGC ( iscsi, "iSCSI %p invalid CHAP response length\n",
+		       iscsi );
+		return -EPROTO;
+	}
+
+	/* Process response an octet at a time */
+	for ( i = 0 ; ( value[0] && value[1] ) ; value += 2, i++ ) {
+		memcpy ( buf, value, 2 );
+		buf[2] = 0;
+		byte = strtoul ( buf, &endp, 16 );
+		if ( *endp != '\0' ) {
+			DBGC ( iscsi, "iSCSI %p saw invalid CHAP response "
+			       "byte \"%s\"\n", iscsi, buf );
+			return -EPROTO;
+		}
+		if ( byte != iscsi->chap.response[i] ) {
+			DBGC ( iscsi, "iSCSI %p saw incorrect CHAP "
+			       "response\n", iscsi );
+			return -EACCES;
+		}
+	}
+	assert ( i == iscsi->chap.response_len );
+
+	/* Mark session as authenticated */
+	iscsi->status |= ISCSI_STATUS_AUTH_REVERSE_OK;
+
+	return 0;
+}
+
+/** An iSCSI text string that we want to handle */
+struct iscsi_string_type {
+	/** String key
+	 *
+	 * This is the portion up to and including the "=" sign,
+	 * e.g. "InitiatorName=", "CHAP_A=", etc.
+	 */
+	const char *key;
+	/** Handle iSCSI string value
+	 *
+	 * @v iscsi		iSCSI session
+	 * @v value		iSCSI string value
+	 * @ret rc		Return status code
+	 */
+	int ( * handle ) ( struct iscsi_session *iscsi, const char *value );
+};
+
+/** iSCSI text strings that we want to handle */
+static struct iscsi_string_type iscsi_string_types[] = {
+	{ "TargetAddress=", iscsi_handle_targetaddress_value },
+	{ "AuthMethod=", iscsi_handle_authmethod_value },
+	{ "CHAP_A=", iscsi_handle_chap_a_value },
+	{ "CHAP_I=", iscsi_handle_chap_i_value },
+	{ "CHAP_C=", iscsi_handle_chap_c_value },
+	{ "CHAP_N=", iscsi_handle_chap_n_value },
+	{ "CHAP_R=", iscsi_handle_chap_r_value },
+	{ NULL, NULL }
+};
+
+/**
+ * Handle iSCSI string
+ *
+ * @v iscsi		iSCSI session
+ * @v string		iSCSI string (in "key=value" format)
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_string ( struct iscsi_session *iscsi,
+				 const char *string ) {
+	struct iscsi_string_type *type;
+	size_t key_len;
+	int rc;
+
+	for ( type = iscsi_string_types ; type->key ; type++ ) {
+		key_len = strlen ( type->key );
+		if ( strncmp ( string, type->key, key_len ) != 0 )
+			continue;
+		DBGC ( iscsi, "iSCSI %p handling %s\n", iscsi, string );
+		if ( ( rc = type->handle ( iscsi,
+					   ( string + key_len ) ) ) != 0 ) {
+			DBGC ( iscsi, "iSCSI %p could not handle %s: %s\n",
+			       iscsi, string, strerror ( rc ) );
+			return rc;
+		}
+		return 0;
+	}
+	DBGC ( iscsi, "iSCSI %p ignoring %s\n", iscsi, string );
+	return 0;
+}
+
+/**
+ * Handle iSCSI strings
+ *
+ * @v iscsi		iSCSI session
+ * @v string		iSCSI string buffer
+ * @v len		Length of string buffer
+ * @ret rc		Return status code
+ */
+static int iscsi_handle_strings ( struct iscsi_session *iscsi,
+				  const char *strings, size_t len ) {
+	size_t string_len;
+	int rc;
+
+	/* Handle each string in turn, taking care not to overrun the
+	 * data buffer in case of badly-terminated data.
+	 */
+	while ( 1 ) {
+		string_len = ( strnlen ( strings, len ) + 1 );
+		if ( string_len > len )
+			break;
+		if ( ( rc = iscsi_handle_string ( iscsi, strings ) ) != 0 )
+			return rc;
+		strings += string_len;
+		len -= string_len;
+	}
+	return 0;
+}
+
+/**
+ * Receive PDU data into buffer
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Data to receive
+ * @v len		Length of data
+ * @ret rc		Return status code
+ *
+ * This can be used when the RX PDU type handler wishes to buffer up
+ * all received data and process the PDU as a single unit.  The caller
+ * is repsonsible for calling iscsi_rx_buffered_data_done() after
+ * processing the data.
+ */
+static int iscsi_rx_buffered_data ( struct iscsi_session *iscsi,
+				    const void *data, size_t len ) {
+
+	/* Allocate buffer on first call */
+	if ( ! iscsi->rx_buffer ) {
+		iscsi->rx_buffer = malloc ( iscsi->rx_len );
+		if ( ! iscsi->rx_buffer )
+			return -ENOMEM;
+	}
+
+	/* Copy data to buffer */
+	assert ( ( iscsi->rx_offset + len ) <= iscsi->rx_len );
+	memcpy ( ( iscsi->rx_buffer + iscsi->rx_offset ), data, len );
+
+	return 0;
+}
+
+/**
+ * Convert iSCSI response status to return status code
+ *
+ * @v status_class	iSCSI status class
+ * @v status_detail	iSCSI status detail
+ * @ret rc		Return status code
+ */
+static int iscsi_status_to_rc ( unsigned int status_class,
+				unsigned int status_detail ) {
+	switch ( status_class ) {
+	case ISCSI_STATUS_INITIATOR_ERROR :
+		switch ( status_detail ) {
+		case ISCSI_STATUS_INITIATOR_ERROR_AUTHENTICATION :
+			return -EACCES;
+		case ISCSI_STATUS_INITIATOR_ERROR_AUTHORISATION :
+			return -EPERM;
+		case ISCSI_STATUS_INITIATOR_ERROR_NOT_FOUND :
+		case ISCSI_STATUS_INITIATOR_ERROR_REMOVED :
+			return -ENODEV;
+		default :
+			return -ENOTSUP;
+		}
+	case ISCSI_STATUS_TARGET_ERROR :
+		return -EIO;
+	default :
+		return -EINVAL;
+	}
+}
+
+/**
+ * Receive data segment of an iSCSI login response PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ */
+static int iscsi_rx_login_response ( struct iscsi_session *iscsi,
+				     const void *data, size_t len,
+				     size_t remaining ) {
+	struct iscsi_bhs_login_response *response
+		= &iscsi->rx_bhs.login_response;
+	int rc;
+
+	/* Buffer up the PDU data */
+	if ( ( rc = iscsi_rx_buffered_data ( iscsi, data, len ) ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p could not buffer login response: %s\n",
+		       iscsi, strerror ( rc ) );
+		return rc;
+	}
+	if ( remaining )
+		return 0;
+
+	/* Process string data and discard string buffer */
+	if ( ( rc = iscsi_handle_strings ( iscsi, iscsi->rx_buffer,
+					   iscsi->rx_len ) ) != 0 )
+		return rc;
+	iscsi_rx_buffered_data_done ( iscsi );
+
+	/* Check for login redirection */
+	if ( response->status_class == ISCSI_STATUS_REDIRECT ) {
+		DBGC ( iscsi, "iSCSI %p redirecting to new server\n", iscsi );
+		iscsi_close_connection ( iscsi, 0 );
+		if ( ( rc = iscsi_open_connection ( iscsi ) ) != 0 ) {
+			DBGC ( iscsi, "iSCSI %p could not redirect: %s\n ",
+			       iscsi, strerror ( rc ) );
+			return rc;
+		}
+		return 0;
+	}
+
+	/* Check for fatal errors */
+	if ( response->status_class != 0 ) {
+		DBGC ( iscsi, "iSCSI login failure: class %02x detail %02x\n",
+		       response->status_class, response->status_detail );
+		rc = iscsi_status_to_rc ( response->status_class,
+					  response->status_detail );
+		iscsi->instant_rc = rc;
+		return rc;
+	}
+
+	/* Handle login transitions */
+	if ( response->flags & ISCSI_LOGIN_FLAG_TRANSITION ) {
+		iscsi->status &= ~( ISCSI_STATUS_PHASE_MASK |
+				    ISCSI_STATUS_STRINGS_MASK );
+		switch ( response->flags & ISCSI_LOGIN_NSG_MASK ) {
+		case ISCSI_LOGIN_NSG_OPERATIONAL_NEGOTIATION:
+			iscsi->status |=
+				( ISCSI_STATUS_OPERATIONAL_NEGOTIATION_PHASE |
+				  ISCSI_STATUS_STRINGS_OPERATIONAL );
+			break;
+		case ISCSI_LOGIN_NSG_FULL_FEATURE_PHASE:
+			iscsi->status |= ISCSI_STATUS_FULL_FEATURE_PHASE;
+			break;
+		default:
+			DBGC ( iscsi, "iSCSI %p got invalid response flags "
+			       "%02x\n", iscsi, response->flags );
+			return -EIO;
+		}
+	}
+
+	/* Send next login request PDU if we haven't reached the full
+	 * feature phase yet.
+	 */
+	if ( ( iscsi->status & ISCSI_STATUS_PHASE_MASK ) !=
+	     ISCSI_STATUS_FULL_FEATURE_PHASE ) {
+		iscsi_start_login ( iscsi );
+		return 0;
+	}
+
+	/* Check that target authentication was successful (if required) */
+	if ( ( iscsi->status & ISCSI_STATUS_AUTH_REVERSE_REQUIRED ) &&
+	     ! ( iscsi->status & ISCSI_STATUS_AUTH_REVERSE_OK ) ) {
+		DBGC ( iscsi, "iSCSI %p nefarious target tried to bypass "
+		       "authentication\n", iscsi );
+		return -EPROTO;
+	}
+
+	/* Reset retry count */
+	iscsi->retry_count = 0;
+
+	/* Record TSIH for future reference */
+	iscsi->tsih = ntohl ( response->tsih );
+	
+	/* Send the actual SCSI command */
+	iscsi_start_command ( iscsi );
+
+	return 0;
+}
+
+/****************************************************************************
+ *
+ * iSCSI to socket interface
+ *
+ */
+
+/**
+ * Start up a new TX PDU
+ *
+ * @v iscsi		iSCSI session
+ *
+ * This initiates the process of sending a new PDU.  Only one PDU may
+ * be in transit at any one time.
+ */
+static void iscsi_start_tx ( struct iscsi_session *iscsi ) {
+	assert ( iscsi->tx_state == ISCSI_TX_IDLE );
+	
+	/* Initialise TX BHS */
+	memset ( &iscsi->tx_bhs, 0, sizeof ( iscsi->tx_bhs ) );
+
+	/* Flag TX engine to start transmitting */
+	iscsi->tx_state = ISCSI_TX_BHS;
+}
+
+/**
+ * Transmit nothing
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ */
+static int iscsi_tx_nothing ( struct iscsi_session *iscsi __unused ) {
+	return 0;
+}
+
+/**
+ * Transmit basic header segment of an iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ */
+static int iscsi_tx_bhs ( struct iscsi_session *iscsi ) {
+	return xfer_deliver_raw ( &iscsi->socket,  &iscsi->tx_bhs,
+				  sizeof ( iscsi->tx_bhs ) );
+}
+
+/**
+ * Transmit data segment of an iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ * 
+ * Handle transmission of part of a PDU data segment.  iscsi::tx_bhs
+ * will be valid when this is called.
+ */
+static int iscsi_tx_data ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
+
+	switch ( common->opcode & ISCSI_OPCODE_MASK ) {
+	case ISCSI_OPCODE_DATA_OUT:
+		return iscsi_tx_data_out ( iscsi );
+	case ISCSI_OPCODE_LOGIN_REQUEST:
+		return iscsi_tx_login_request ( iscsi );
+	default:
+		/* Nothing to send in other states */
+		return 0;
+	}
+}
+
+/**
+ * Transmit data padding of an iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ * 
+ * Handle transmission of any data padding in a PDU data segment.
+ * iscsi::tx_bhs will be valid when this is called.
+ */
+static int iscsi_tx_data_padding ( struct iscsi_session *iscsi ) {
+	static const char pad[] = { '\0', '\0', '\0' };
+	struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
+	size_t pad_len;
+	
+	pad_len = ISCSI_DATA_PAD_LEN ( common->lengths );
+	if ( ! pad_len )
+		return 0;
+
+	return xfer_deliver_raw ( &iscsi->socket, pad, pad_len );
+}
+
+/**
+ * Complete iSCSI PDU transmission
+ *
+ * @v iscsi		iSCSI session
+ *
+ * Called when a PDU has been completely transmitted and the TX state
+ * machine is about to enter the idle state.  iscsi::tx_bhs will be
+ * valid for the just-completed PDU when this is called.
+ */
+static void iscsi_tx_done ( struct iscsi_session *iscsi ) {
+	struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
+
+	switch ( common->opcode & ISCSI_OPCODE_MASK ) {
+	case ISCSI_OPCODE_DATA_OUT:
+		iscsi_data_out_done ( iscsi );
+	case ISCSI_OPCODE_LOGIN_REQUEST:
+		iscsi_login_request_done ( iscsi );
+	default:
+		/* No action */
+		break;
+	}
+}
+
+/**
+ * Transmit iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v buf		Temporary data buffer
+ * @v len		Length of temporary data buffer
+ * 
+ * Constructs data to be sent for the current TX state
+ */
+static void iscsi_tx_step ( struct process *process ) {
+	struct iscsi_session *iscsi =
+		container_of ( process, struct iscsi_session, process );
+	struct iscsi_bhs_common *common = &iscsi->tx_bhs.common;
+	int ( * tx ) ( struct iscsi_session *iscsi );
+	enum iscsi_tx_state next_state;
+	size_t tx_len;
+	int rc;
+
+	/* Select fragment to transmit */
+	while ( 1 ) {
+		switch ( iscsi->tx_state ) {
+		case ISCSI_TX_IDLE:
+			/* Stop processing */
+			return;
+		case ISCSI_TX_BHS:
+			tx = iscsi_tx_bhs;
+			tx_len = sizeof ( iscsi->tx_bhs );
+			next_state = ISCSI_TX_AHS;
+			break;
+		case ISCSI_TX_AHS:
+			tx = iscsi_tx_nothing;
+			tx_len = 0;
+			next_state = ISCSI_TX_DATA;
+			break;
+		case ISCSI_TX_DATA:
+			tx = iscsi_tx_data;
+			tx_len = ISCSI_DATA_LEN ( common->lengths );
+			next_state = ISCSI_TX_DATA_PADDING;
+			break;
+		case ISCSI_TX_DATA_PADDING:
+			tx = iscsi_tx_data_padding;
+			tx_len = ISCSI_DATA_PAD_LEN ( common->lengths );
+			next_state = ISCSI_TX_IDLE;
+			break;
+		default:
+			assert ( 0 );
+			return;
+		}
+
+		/* Check for window availability, if needed */
+		if ( tx_len && ( xfer_window ( &iscsi->socket ) == 0 ) ) {
+			/* Cannot transmit at this point; stop processing */
+			return;
+		}
+
+		/* Transmit data */
+		if ( ( rc = tx ( iscsi ) ) != 0 ) {
+			DBGC ( iscsi, "iSCSI %p could not transmit: %s\n",
+			       iscsi, strerror ( rc ) );
+			return;
+		}
+
+		/* Move to next state */
+		iscsi->tx_state = next_state;
+		if ( next_state == ISCSI_TX_IDLE )
+			iscsi_tx_done ( iscsi );
+	}
+}
+
+/**
+ * Receive basic header segment of an iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ *
+ * This fills in iscsi::rx_bhs with the data from the BHS portion of
+ * the received PDU.
+ */
+static int iscsi_rx_bhs ( struct iscsi_session *iscsi, const void *data,
+			  size_t len, size_t remaining __unused ) {
+	memcpy ( &iscsi->rx_bhs.bytes[iscsi->rx_offset], data, len );
+	if ( ( iscsi->rx_offset + len ) >= sizeof ( iscsi->rx_bhs ) ) {
+		DBGC2 ( iscsi, "iSCSI %p received PDU opcode %#x len %#x\n",
+			iscsi, iscsi->rx_bhs.common.opcode,
+			ISCSI_DATA_LEN ( iscsi->rx_bhs.common.lengths ) );
+	}
+	return 0;
+}
+
+/**
+ * Discard portion of an iSCSI PDU.
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ *
+ * This discards data from a portion of a received PDU.
+ */
+static int iscsi_rx_discard ( struct iscsi_session *iscsi __unused,
+			      const void *data __unused, size_t len __unused,
+			      size_t remaining __unused ) {
+	/* Do nothing */
+	return 0;
+}
+
+/**
+ * Receive data segment of an iSCSI PDU
+ *
+ * @v iscsi		iSCSI session
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v remaining		Data remaining after this data
+ * @ret rc		Return status code
+ *
+ * Handle processing of part of a PDU data segment.  iscsi::rx_bhs
+ * will be valid when this is called.
+ */
+static int iscsi_rx_data ( struct iscsi_session *iscsi, const void *data,
+			   size_t len, size_t remaining ) {
+	struct iscsi_bhs_common_response *response
+		= &iscsi->rx_bhs.common_response;
+
+	/* Update cmdsn and statsn */
+	iscsi->cmdsn = ntohl ( response->expcmdsn );
+	iscsi->statsn = ntohl ( response->statsn );
+
+	switch ( response->opcode & ISCSI_OPCODE_MASK ) {
+	case ISCSI_OPCODE_LOGIN_RESPONSE:
+		return iscsi_rx_login_response ( iscsi, data, len, remaining );
+	case ISCSI_OPCODE_SCSI_RESPONSE:
+		return iscsi_rx_scsi_response ( iscsi, data, len, remaining );
+	case ISCSI_OPCODE_DATA_IN:
+		return iscsi_rx_data_in ( iscsi, data, len, remaining );
+	case ISCSI_OPCODE_R2T:
+		return iscsi_rx_r2t ( iscsi, data, len, remaining );
+	default:
+		if ( remaining )
+			return 0;
+		DBGC ( iscsi, "iSCSI %p unknown opcode %02x\n", iscsi,
+		       response->opcode );
+		return -ENOTSUP;
+	}
+}
+
+/**
+ * Receive new data
+ *
+ * @v socket		Transport layer interface
+ * @v data		Received data
+ * @v len		Length of received data
+ * @ret rc		Return status code
+ *
+ * This handles received PDUs.  The receive strategy is to fill in
+ * iscsi::rx_bhs with the contents of the BHS portion of the PDU,
+ * throw away any AHS portion, and then process each part of the data
+ * portion as it arrives.  The data processing routine therefore
+ * always has a full copy of the BHS available, even for portions of
+ * the data in different packets to the BHS.
+ */
+static int iscsi_socket_deliver_raw ( struct xfer_interface *socket,
+				      const void *data, size_t len ) {
+	struct iscsi_session *iscsi =
+		container_of ( socket, struct iscsi_session, socket );
+	struct iscsi_bhs_common *common = &iscsi->rx_bhs.common;
+	int ( * rx ) ( struct iscsi_session *iscsi, const void *data,
+		       size_t len, size_t remaining );
+	enum iscsi_rx_state next_state;
+	size_t frag_len;
+	size_t remaining;
+	int rc;
+
+	while ( 1 ) {
+		switch ( iscsi->rx_state ) {
+		case ISCSI_RX_BHS:
+			rx = iscsi_rx_bhs;
+			iscsi->rx_len = sizeof ( iscsi->rx_bhs );
+			next_state = ISCSI_RX_AHS;			
+			break;
+		case ISCSI_RX_AHS:
+			rx = iscsi_rx_discard;
+			iscsi->rx_len = 4 * ISCSI_AHS_LEN ( common->lengths );
+			next_state = ISCSI_RX_DATA;
+			break;
+		case ISCSI_RX_DATA:
+			rx = iscsi_rx_data;
+			iscsi->rx_len = ISCSI_DATA_LEN ( common->lengths );
+			next_state = ISCSI_RX_DATA_PADDING;
+			break;
+		case ISCSI_RX_DATA_PADDING:
+			rx = iscsi_rx_discard;
+			iscsi->rx_len = ISCSI_DATA_PAD_LEN ( common->lengths );
+			next_state = ISCSI_RX_BHS;
+			break;
+		default:
+			assert ( 0 );
+			return -EINVAL;
+		}
+
+		frag_len = iscsi->rx_len - iscsi->rx_offset;
+		if ( frag_len > len )
+			frag_len = len;
+		remaining = iscsi->rx_len - iscsi->rx_offset - frag_len;
+		if ( ( rc = rx ( iscsi, data, frag_len, remaining ) ) != 0 ) {
+			DBGC ( iscsi, "iSCSI %p could not process received "
+			       "data: %s\n", iscsi, strerror ( rc ) );
+			iscsi_close_connection ( iscsi, rc );
+			iscsi_scsi_done ( iscsi, rc );
+			return rc;
+		}
+
+		iscsi->rx_offset += frag_len;
+		data += frag_len;
+		len -= frag_len;
+
+		/* If all the data for this state has not yet been
+		 * received, stay in this state for now.
+		 */
+		if ( iscsi->rx_offset != iscsi->rx_len )
+			return 0;
+
+		iscsi->rx_state = next_state;
+		iscsi->rx_offset = 0;
+	}
+
+	return 0;
+}
+
+/**
+ * Handle stream connection closure
+ *
+ * @v socket		Transport layer interface
+ * @v rc		Reason for close
+ *
+ */
+static void iscsi_socket_close ( struct xfer_interface *socket, int rc ) {
+	struct iscsi_session *iscsi =
+		container_of ( socket, struct iscsi_session, socket );
+
+	/* Even a graceful close counts as an error for iSCSI */
+	if ( ! rc )
+		rc = -ECONNRESET;
+
+	/* Close session cleanly */
+	iscsi_close_connection ( iscsi, rc );
+
+	/* Retry connection if within the retry limit, otherwise fail */
+	if ( ++iscsi->retry_count <= ISCSI_MAX_RETRIES ) {
+		DBGC ( iscsi, "iSCSI %p retrying connection (retry #%d)\n",
+		       iscsi, iscsi->retry_count );
+		if ( ( rc = iscsi_open_connection ( iscsi ) ) != 0 ) {
+			DBGC ( iscsi, "iSCSI %p could not reconnect: %s\n",
+			       iscsi, strerror ( rc ) );
+			iscsi_scsi_done ( iscsi, rc );
+		}
+	} else {
+		DBGC ( iscsi, "iSCSI %p retry count exceeded\n", iscsi );
+		iscsi->instant_rc = rc;
+		iscsi_scsi_done ( iscsi, rc );
+	}
+}
+
+/**
+ * Handle redirection event
+ *
+ * @v socket		Transport layer interface
+ * @v type		Location type
+ * @v args		Remaining arguments depend upon location type
+ * @ret rc		Return status code
+ */
+static int iscsi_vredirect ( struct xfer_interface *socket, int type,
+			     va_list args ) {
+	struct iscsi_session *iscsi =
+		container_of ( socket, struct iscsi_session, socket );
+	va_list tmp;
+	struct sockaddr *peer;
+
+	/* Intercept redirects to a LOCATION_SOCKET and record the IP
+	 * address for the iBFT.  This is a bit of a hack, but avoids
+	 * inventing an ioctl()-style call to retrieve the socket
+	 * address from a data-xfer interface.
+	 */
+	if ( type == LOCATION_SOCKET ) {
+		va_copy ( tmp, args );
+		( void ) va_arg ( tmp, int ); /* Discard "semantics" */
+		peer = va_arg ( tmp, struct sockaddr * );
+		memcpy ( &iscsi->target_sockaddr, peer,
+			 sizeof ( iscsi->target_sockaddr ) );
+		va_end ( tmp );
+	}
+
+	return xfer_vreopen ( socket, type, args );
+}
+			     
+
+/** iSCSI socket operations */
+static struct xfer_interface_operations iscsi_socket_operations = {
+	.close		= iscsi_socket_close,
+	.vredirect	= iscsi_vredirect,
+	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
+	.deliver_iob	= xfer_deliver_as_raw,
+	.deliver_raw	= iscsi_socket_deliver_raw,
+};
+
+
+/****************************************************************************
+ *
+ * iSCSI command issuing
+ *
+ */
+
+/**
+ * Issue SCSI command
+ *
+ * @v scsi		SCSI device
+ * @v command		SCSI command
+ * @ret rc		Return status code
+ */
+static int iscsi_command ( struct scsi_device *scsi,
+			   struct scsi_command *command ) {
+	struct iscsi_session *iscsi =
+		container_of ( scsi->backend, struct iscsi_session, refcnt );
+	int rc;
+
+	/* Abort immediately if we have a recorded permanent failure */
+	if ( iscsi->instant_rc )
+		return iscsi->instant_rc;
+
+	/* Record SCSI command */
+	iscsi->command = command;
+
+	/* Issue command or open connection as appropriate */
+	if ( iscsi->status ) {
+		iscsi_start_command ( iscsi );
+	} else {
+		if ( ( rc = iscsi_open_connection ( iscsi ) ) != 0 ) {
+			iscsi->command = NULL;
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Shut down iSCSI interface
+ *
+ * @v scsi		SCSI device
+ */
+void iscsi_detach ( struct scsi_device *scsi ) {
+	struct iscsi_session *iscsi =
+		container_of ( scsi->backend, struct iscsi_session, refcnt );
+
+	xfer_nullify ( &iscsi->socket );
+	iscsi_close_connection ( iscsi, 0 );
+	process_del ( &iscsi->process );
+	scsi->command = scsi_detached_command;
+	ref_put ( scsi->backend );
+	scsi->backend = NULL;
+}
+
+/****************************************************************************
+ *
+ * Instantiator
+ *
+ */
+
+/** iSCSI root path components (as per RFC4173) */
+enum iscsi_root_path_component {
+	RP_LITERAL = 0,
+	RP_SERVERNAME,
+	RP_PROTOCOL,
+	RP_PORT,
+	RP_LUN,
+	RP_TARGETNAME,
+	NUM_RP_COMPONENTS
+};
+
+/**
+ * Parse iSCSI root path
+ *
+ * @v iscsi		iSCSI session
+ * @v root_path		iSCSI root path (as per RFC4173)
+ * @ret rc		Return status code
+ */
+static int iscsi_parse_root_path ( struct iscsi_session *iscsi,
+				   const char *root_path ) {
+	char rp_copy[ strlen ( root_path ) + 1 ];
+	char *rp_comp[NUM_RP_COMPONENTS];
+	char *rp = rp_copy;
+	int i = 0;
+	int rc;
+
+	/* Split root path into component parts */
+	strcpy ( rp_copy, root_path );
+	while ( 1 ) {
+		rp_comp[i++] = rp;
+		if ( i == NUM_RP_COMPONENTS )
+			break;
+		for ( ; *rp != ':' ; rp++ ) {
+			if ( ! *rp ) {
+				DBGC ( iscsi, "iSCSI %p root path \"%s\" "
+				       "too short\n", iscsi, root_path );
+				return -EINVAL;
+			}
+		}
+		*(rp++) = '\0';
+	}
+
+	/* Use root path components to configure iSCSI session */
+	iscsi->target_address = strdup ( rp_comp[RP_SERVERNAME] );
+	if ( ! iscsi->target_address )
+		return -ENOMEM;
+	iscsi->target_port = strtoul ( rp_comp[RP_PORT], NULL, 10 );
+	if ( ! iscsi->target_port )
+		iscsi->target_port = ISCSI_PORT;
+	if ( ( rc = scsi_parse_lun ( rp_comp[RP_LUN], &iscsi->lun ) ) != 0 ) {
+		DBGC ( iscsi, "iSCSI %p invalid LUN \"%s\"\n",
+		       iscsi, rp_comp[RP_LUN] );
+		return rc;
+	}
+	iscsi->target_iqn = strdup ( rp_comp[RP_TARGETNAME] );
+	if ( ! iscsi->target_iqn )
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * Set iSCSI authentication details
+ *
+ * @v iscsi		iSCSI session
+ * @v initiator_username Initiator username, if any
+ * @v initiator_password Initiator password, if any
+ * @v target_username	Target username, if any
+ * @v target_password	Target password, if any
+ * @ret rc		Return status code
+ */
+static int iscsi_set_auth ( struct iscsi_session *iscsi,
+			    const char *initiator_username,
+			    const char *initiator_password,
+			    const char *target_username,
+			    const char *target_password ) {
+
+	/* Check for initiator or target credentials */
+	if ( initiator_username || initiator_password ||
+	     target_username || target_password ) {
+
+		/* We must have at least an initiator username+password */
+		if ( ! ( initiator_username && initiator_password ) )
+			goto invalid_auth;
+
+		/* Store initiator credentials */
+		iscsi->initiator_username = strdup ( initiator_username );
+		if ( ! iscsi->initiator_username )
+			return -ENOMEM;
+		iscsi->initiator_password = strdup ( initiator_password );
+		if ( ! iscsi->initiator_password )
+			return -ENOMEM;
+
+		/* Check for target credentials */
+		if ( target_username || target_password ) {
+
+			/* We must have target username+password */
+			if ( ! ( target_username && target_password ) )
+				goto invalid_auth;
+
+			/* Store target credentials */
+			iscsi->target_username = strdup ( target_username );
+			if ( ! iscsi->target_username )
+				return -ENOMEM;
+			iscsi->target_password = strdup ( target_password );
+			if ( ! iscsi->target_password )
+				return -ENOMEM;
+		}
+	}
+
+	return 0;
+
+ invalid_auth:
+	DBGC ( iscsi, "iSCSI %p invalid credentials: initiator "
+	       "%sname,%spw, target %sname,%spw\n", iscsi,
+	       ( initiator_username ? "" : "no " ),
+	       ( initiator_password ? "" : "no " ),
+	       ( target_username ? "" : "no " ),
+	       ( target_password ? "" : "no " ) );
+	return -EINVAL;
+}
+
+/**
+ * Attach iSCSI interface
+ *
+ * @v scsi		SCSI device
+ * @v root_path		iSCSI root path (as per RFC4173)
+ * @ret rc		Return status code
+ */
+int iscsi_attach ( struct scsi_device *scsi, const char *root_path ) {
+	struct iscsi_session *iscsi;
+	int rc;
+
+	/* Allocate and initialise structure */
+	iscsi = zalloc ( sizeof ( *iscsi ) );
+	if ( ! iscsi )
+		return -ENOMEM;
+	iscsi->refcnt.free = iscsi_free;
+	xfer_init ( &iscsi->socket, &iscsi_socket_operations, &iscsi->refcnt );
+	process_init ( &iscsi->process, iscsi_tx_step, &iscsi->refcnt );
+
+	/* Parse root path */
+	if ( ( rc = iscsi_parse_root_path ( iscsi, root_path ) ) != 0 )
+		goto err;
+	/* Set fields not specified by root path */
+	if ( ( rc = iscsi_set_auth ( iscsi,
+				     iscsi_initiator_username,
+				     iscsi_initiator_password,
+				     iscsi_target_username,
+				     iscsi_target_password ) ) != 0 )
+		goto err;
+
+	/* Sanity checks */
+	if ( ! iscsi->target_address ) {
+		DBGC ( iscsi, "iSCSI %p does not yet support discovery\n",
+		       iscsi );
+		rc = -ENOTSUP;
+		goto err;
+	}
+	if ( ! iscsi->target_iqn ) {
+		DBGC ( iscsi, "iSCSI %p no target address supplied in %s\n",
+		       iscsi, root_path );
+		rc = -EINVAL;
+		goto err;
+	}
+
+	/* Attach parent interface, mortalise self, and return */
+	scsi->backend = ref_get ( &iscsi->refcnt );
+	scsi->command = iscsi_command;
+	ref_put ( &iscsi->refcnt );
+	return 0;
+	
+ err:
+	ref_put ( &iscsi->refcnt );
+	return rc;
+}
+
+/****************************************************************************
+ *
+ * Settings
+ *
+ */
+
+/** iSCSI initiator IQN setting */
+struct setting initiator_iqn_setting __setting = {
+	.name = "initiator-iqn",
+	.description = "iSCSI initiator name",
+	.tag = DHCP_ISCSI_INITIATOR_IQN,
+	.type = &setting_type_string,
+};
+
+/** iSCSI reverse username setting */
+struct setting reverse_username_setting __setting = {
+	.name = "reverse-username",
+	.description = "Reverse user name",
+	.tag = DHCP_EB_REVERSE_USERNAME,
+	.type = &setting_type_string,
+};
+
+/** iSCSI reverse password setting */
+struct setting reverse_password_setting __setting = {
+	.name = "reverse-password",
+	.description = "Reverse password",
+	.tag = DHCP_EB_REVERSE_PASSWORD,
+	.type = &setting_type_string,
+};
+
+/** An iSCSI string setting */
+struct iscsi_string_setting {
+	/** Setting */
+	struct setting *setting;
+	/** String to update */
+	char **string;
+	/** String prefix */
+	const char *prefix;
+};
+
+/** iSCSI string settings */
+static struct iscsi_string_setting iscsi_string_settings[] = {
+	{
+		.setting = &initiator_iqn_setting,
+		.string = &iscsi_explicit_initiator_iqn,
+		.prefix = "",
+	},
+	{
+		.setting = &username_setting,
+		.string = &iscsi_initiator_username,
+		.prefix = "",
+	},
+	{
+		.setting = &password_setting,
+		.string = &iscsi_initiator_password,
+		.prefix = "",
+	},
+	{
+		.setting = &reverse_username_setting,
+		.string = &iscsi_target_username,
+		.prefix = "",
+	},
+	{
+		.setting = &reverse_password_setting,
+		.string = &iscsi_target_password,
+		.prefix = "",
+	},
+	{
+		.setting = &hostname_setting,
+		.string = &iscsi_default_initiator_iqn,
+		.prefix = "iqn.2000-01.org.etherboot:",
+	},
+};
+
+/**
+ * Apply iSCSI setting
+ *
+ * @v setting		iSCSI string setting
+ * @ret rc		Return status code
+ */
+static int apply_iscsi_string_setting ( struct iscsi_string_setting *setting ){
+	size_t prefix_len;
+	int setting_len;
+	size_t len;
+	int check_len;
+	char *p;
+
+	/* Free old string */
+	free ( *setting->string );
+	*setting->string = NULL;
+
+	/* Allocate new string */
+	prefix_len = strlen ( setting->prefix );
+	setting_len = fetch_setting_len ( NULL, setting->setting );
+	if ( setting_len < 0 ) {
+		/* Missing settings are not errors; leave strings as NULL */
+		return 0;
+	}
+	len = ( prefix_len + setting_len + 1 );
+	p = *setting->string = malloc ( len );
+	if ( ! p )
+		return -ENOMEM;
+
+	/* Fill new string */
+	strcpy ( p, setting->prefix );
+	check_len = fetch_string_setting ( NULL, setting->setting,
+					   ( p + prefix_len ),
+					   ( len - prefix_len ) );
+	assert ( check_len == setting_len );
+
+	return 0;
+}
+
+/**
+ * Apply iSCSI settings
+ *
+ * @ret rc		Return status code
+ */
+static int apply_iscsi_settings ( void ) {
+	struct iscsi_string_setting *setting;
+	unsigned int i;
+	int rc;
+
+	for ( i = 0 ; i < ( sizeof ( iscsi_string_settings ) /
+			    sizeof ( iscsi_string_settings[0] ) ) ; i++ ) {
+		setting = &iscsi_string_settings[i];
+		if ( ( rc = apply_iscsi_string_setting ( setting ) ) != 0 ) {
+			DBG ( "iSCSI could not apply setting %s\n",
+			      setting->setting->name );
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+/** iSCSI settings applicator */
+struct settings_applicator iscsi_settings_applicator __settings_applicator = {
+	.apply = apply_iscsi_settings,
+};
+
+/****************************************************************************
+ *
+ * Initiator name
+ *
+ */
+
+/**
+ * Get iSCSI initiator IQN
+ *
+ * @v iscsi		iSCSI session
+ * @ret rc		Return status code
+ */
+const char * iscsi_initiator_iqn ( void ) {
+
+	if ( iscsi_explicit_initiator_iqn )
+		return iscsi_explicit_initiator_iqn;
+	if ( iscsi_default_initiator_iqn )
+		return iscsi_default_initiator_iqn;
+	return "iqn.2000-09.org.etherboot:UNKNOWN";
+}