--- /dev/null
+/*
+ * Copyright (C) 2008 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 <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/dhcp.h>
+#include <ipxe/dhcpopts.h>
+#include <ipxe/dhcppkt.h>
+
+/** @file
+ *
+ * DHCP packets
+ *
+ */
+
+/****************************************************************************
+ *
+ * DHCP packet raw interface
+ *
+ */
+
+/**
+ * Calculate used length of an IPv4 field within a DHCP packet
+ *
+ * @v data Field data
+ * @v len Length of field
+ * @ret used Used length of field
+ */
+static size_t used_len_ipv4 ( const void *data, size_t len __unused ) {
+ const struct in_addr *in = data;
+
+ return ( in->s_addr ? sizeof ( *in ) : 0 );
+}
+
+/**
+ * Calculate used length of a string field within a DHCP packet
+ *
+ * @v data Field data
+ * @v len Length of field
+ * @ret used Used length of field
+ */
+static size_t used_len_string ( const void *data, size_t len ) {
+ return strnlen ( data, len );
+}
+
+/** A dedicated field within a DHCP packet */
+struct dhcp_packet_field {
+ /** Settings tag number */
+ unsigned int tag;
+ /** Offset within DHCP packet */
+ uint16_t offset;
+ /** Length of field */
+ uint16_t len;
+ /** Calculate used length of field
+ *
+ * @v data Field data
+ * @v len Length of field
+ * @ret used Used length of field
+ */
+ size_t ( * used_len ) ( const void *data, size_t len );
+};
+
+/** Declare a dedicated field within a DHCP packet
+ *
+ * @v _tag Settings tag number
+ * @v _field Field name
+ * @v _used_len Function to calculate used length of field
+ */
+#define DHCP_PACKET_FIELD( _tag, _field, _used_len ) { \
+ .tag = (_tag), \
+ .offset = offsetof ( struct dhcphdr, _field ), \
+ .len = sizeof ( ( ( struct dhcphdr * ) 0 )->_field ), \
+ .used_len = _used_len, \
+ }
+
+/** Dedicated fields within a DHCP packet */
+static struct dhcp_packet_field dhcp_packet_fields[] = {
+ DHCP_PACKET_FIELD ( DHCP_EB_YIADDR, yiaddr, used_len_ipv4 ),
+ DHCP_PACKET_FIELD ( DHCP_EB_SIADDR, siaddr, used_len_ipv4 ),
+ DHCP_PACKET_FIELD ( DHCP_TFTP_SERVER_NAME, sname, used_len_string ),
+ DHCP_PACKET_FIELD ( DHCP_BOOTFILE_NAME, file, used_len_string ),
+};
+
+/**
+ * Get address of a DHCP packet field
+ *
+ * @v dhcphdr DHCP packet header
+ * @v field DHCP packet field
+ * @ret data Packet field data
+ */
+static inline void * dhcp_packet_field ( struct dhcphdr *dhcphdr,
+ struct dhcp_packet_field *field ) {
+ return ( ( ( void * ) dhcphdr ) + field->offset );
+}
+
+/**
+ * Find DHCP packet field corresponding to settings tag number
+ *
+ * @v tag Settings tag number
+ * @ret field DHCP packet field, or NULL
+ */
+static struct dhcp_packet_field *
+find_dhcp_packet_field ( unsigned int tag ) {
+ struct dhcp_packet_field *field;
+ unsigned int i;
+
+ for ( i = 0 ; i < ( sizeof ( dhcp_packet_fields ) /
+ sizeof ( dhcp_packet_fields[0] ) ) ; i++ ) {
+ field = &dhcp_packet_fields[i];
+ if ( field->tag == tag )
+ return field;
+ }
+ return NULL;
+}
+
+/**
+ * Check applicability of DHCP setting
+ *
+ * @v dhcppkt DHCP packet
+ * @v tag Setting tag number
+ * @ret applies Setting applies within this settings block
+ */
+static int dhcppkt_applies ( struct dhcp_packet *dhcppkt __unused,
+ unsigned int tag ) {
+
+ return dhcpopt_applies ( tag );
+}
+
+/**
+ * Store value of DHCP packet setting
+ *
+ * @v dhcppkt DHCP packet
+ * @v tag Setting tag number
+ * @v data Setting data, or NULL to clear setting
+ * @v len Length of setting data
+ * @ret rc Return status code
+ */
+int dhcppkt_store ( struct dhcp_packet *dhcppkt, unsigned int tag,
+ const void *data, size_t len ) {
+ struct dhcp_packet_field *field;
+ void *field_data;
+
+ /* If this is a special field, fill it in */
+ if ( ( field = find_dhcp_packet_field ( tag ) ) != NULL ) {
+ if ( len > field->len )
+ return -ENOSPC;
+ field_data = dhcp_packet_field ( dhcppkt->dhcphdr, field );
+ memset ( field_data, 0, field->len );
+ memcpy ( dhcp_packet_field ( dhcppkt->dhcphdr, field ),
+ data, len );
+ /* Erase any equivalent option from the options block */
+ dhcpopt_store ( &dhcppkt->options, tag, NULL, 0 );
+ return 0;
+ }
+
+ /* Otherwise, use the generic options block */
+ return dhcpopt_store ( &dhcppkt->options, tag, data, len );
+}
+
+/**
+ * Fetch value of DHCP packet setting
+ *
+ * @v dhcppkt DHCP packet
+ * @v tag Setting tag number
+ * @v data Buffer to fill with setting data
+ * @v len Length of buffer
+ * @ret len Length of setting data, or negative error
+ */
+int dhcppkt_fetch ( struct dhcp_packet *dhcppkt, unsigned int tag,
+ void *data, size_t len ) {
+ struct dhcp_packet_field *field;
+ void *field_data;
+ size_t field_len = 0;
+
+ /* Identify special field, if any */
+ if ( ( field = find_dhcp_packet_field ( tag ) ) != NULL ) {
+ field_data = dhcp_packet_field ( dhcppkt->dhcphdr, field );
+ field_len = field->used_len ( field_data, field->len );
+ }
+
+ /* Return special field, if it exists and is populated */
+ if ( field_len ) {
+ if ( len > field_len )
+ len = field_len;
+ memcpy ( data, field_data, len );
+ return field_len;
+ }
+
+ /* Otherwise, use the generic options block */
+ return dhcpopt_fetch ( &dhcppkt->options, tag, data, len );
+}
+
+/****************************************************************************
+ *
+ * DHCP packet settings interface
+ *
+ */
+
+/**
+ * Check applicability of DHCP setting
+ *
+ * @v settings Settings block
+ * @v setting Setting
+ * @ret applies Setting applies within this settings block
+ */
+static int dhcppkt_settings_applies ( struct settings *settings,
+ const struct setting *setting ) {
+ struct dhcp_packet *dhcppkt =
+ container_of ( settings, struct dhcp_packet, settings );
+
+ return ( ( setting->scope == NULL ) &&
+ dhcppkt_applies ( dhcppkt, setting->tag ) );
+}
+
+/**
+ * Store value of DHCP setting
+ *
+ * @v settings Settings block
+ * @v setting Setting to store
+ * @v data Setting data, or NULL to clear setting
+ * @v len Length of setting data
+ * @ret rc Return status code
+ */
+static int dhcppkt_settings_store ( struct settings *settings,
+ const struct setting *setting,
+ const void *data, size_t len ) {
+ struct dhcp_packet *dhcppkt =
+ container_of ( settings, struct dhcp_packet, settings );
+
+ return dhcppkt_store ( dhcppkt, setting->tag, data, len );
+}
+
+/**
+ * Fetch value of DHCP setting
+ *
+ * @v settings Settings block, or NULL to search all blocks
+ * @v setting Setting to fetch
+ * @v data Buffer to fill with setting data
+ * @v len Length of buffer
+ * @ret len Length of setting data, or negative error
+ */
+static int dhcppkt_settings_fetch ( struct settings *settings,
+ struct setting *setting,
+ void *data, size_t len ) {
+ struct dhcp_packet *dhcppkt =
+ container_of ( settings, struct dhcp_packet, settings );
+
+ return dhcppkt_fetch ( dhcppkt, setting->tag, data, len );
+}
+
+/** DHCP settings operations */
+static struct settings_operations dhcppkt_settings_operations = {
+ .applies = dhcppkt_settings_applies,
+ .store = dhcppkt_settings_store,
+ .fetch = dhcppkt_settings_fetch,
+};
+
+/****************************************************************************
+ *
+ * Constructor
+ *
+ */
+
+/**
+ * Initialise DHCP packet
+ *
+ * @v dhcppkt DHCP packet structure to fill in
+ * @v data DHCP packet raw data
+ * @v max_len Length of raw data buffer
+ *
+ * Initialise a DHCP packet structure from a data buffer containing a
+ * DHCP packet.
+ */
+void dhcppkt_init ( struct dhcp_packet *dhcppkt, struct dhcphdr *data,
+ size_t len ) {
+ ref_init ( &dhcppkt->refcnt, NULL );
+ dhcppkt->dhcphdr = data;
+ dhcpopt_init ( &dhcppkt->options, &dhcppkt->dhcphdr->options,
+ ( len - offsetof ( struct dhcphdr, options ) ),
+ dhcpopt_no_realloc );
+ settings_init ( &dhcppkt->settings, &dhcppkt_settings_operations,
+ &dhcppkt->refcnt, NULL );
+}
Code Review / kvmfornfv.git / blobdiff