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+#ifndef _GPXE_NET80211_H
+#define _GPXE_NET80211_H
+
+#include <gpxe/process.h>
+#include <gpxe/ieee80211.h>
+#include <gpxe/iobuf.h>
+#include <gpxe/netdevice.h>
+#include <gpxe/rc80211.h>
+
+/** @file
+ *
+ * The gPXE 802.11 MAC layer.
+ */
+
+/*
+ * Major things NOT YET supported:
+ * - any type of security
+ * - 802.11n
+ *
+ * Major things that probably will NEVER be supported, barring a
+ * compelling use case and/or corporate sponsorship:
+ * - QoS
+ * - 802.1X authentication ("WPA Enterprise")
+ * - Contention-free periods
+ * - "ad-hoc" networks (IBSS), monitor mode, host AP mode
+ * - hidden networks on the 5GHz band due to regulatory issues
+ * - spectrum management on the 5GHz band (TPC and DFS), as required
+ * in some non-US regulatory domains
+ * - Clause 14 PHYs (Frequency-Hopping Spread Spectrum on 2.4GHz)
+ * and Clause 16 PHYs (infrared) - I'm not aware of any real-world
+ * use of these.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/* All 802.11 devices are handled using a generic "802.11 device"
+ net_device, with a link in its `priv' field to a net80211_device
+ which we use to handle 802.11-specific details. */
+
+
+/** @defgroup net80211_band RF bands on which an 802.11 device can transmit */
+/** @{ */
+
+/** The 2.4 GHz ISM band, unlicensed in most countries */
+#define NET80211_BAND_2GHZ 0
+/** The band from 4.9 GHz to 5.7 GHz, which tends to be more restricted */
+#define NET80211_BAND_5GHZ 1
+/** Number of RF bands */
+#define NET80211_NR_BANDS 2
+
+/** Bitmask for the 2GHz band */
+#define NET80211_BAND_BIT_2GHZ (1 << 0)
+/** Bitmask for the 5GHz band */
+#define NET80211_BAND_BIT_5GHZ (1 << 1)
+
+/** @} */
+
+
+/** @defgroup net80211_mode 802.11 operation modes supported by hardware */
+/** @{ */
+
+/** 802.11a: 54 Mbps operation using OFDM signaling on the 5GHz band */
+#define NET80211_MODE_A (1 << 0)
+
+/** 802.11b: 1-11 Mbps operation using DSSS/CCK signaling on the 2.4GHz band */
+#define NET80211_MODE_B (1 << 1)
+
+/** 802.11g: 54 Mbps operation using ERP/OFDM signaling on the 2.4GHz band */
+#define NET80211_MODE_G (1 << 2)
+
+/** 802.11n: High-rate operation using MIMO technology on 2.4GHz or 5GHz */
+#define NET80211_MODE_N (1 << 3)
+
+/** @} */
+
+
+/** @defgroup net80211_cfg Constants for the net80211 config callback */
+/** @{ */
+
+/** Channel choice (@c dev->channel) or regulatory parameters have changed */
+#define NET80211_CFG_CHANNEL (1 << 0)
+
+/** Requested transmission rate (@c dev->rate) has changed */
+#define NET80211_CFG_RATE (1 << 1)
+
+/** Association has been established with a new BSS (@c dev->bssid) */
+#define NET80211_CFG_ASSOC (1 << 2)
+
+/** Low-level link parameters (short preamble, protection, etc) have changed */
+#define NET80211_CFG_PHY_PARAMS (1 << 3)
+
+/** @} */
+
+
+/** An 802.11 security handshaking protocol */
+enum net80211_security_proto {
+ /** No security handshaking
+ *
+ * This might be used with an open network or with WEP, as
+ * WEP does not have a cryptographic handshaking phase.
+ */
+ NET80211_SECPROT_NONE = 0,
+
+ /** Pre-shared key handshaking
+ *
+ * This implements the "WPA Personal" handshake. 802.1X
+ * authentication is not performed -- the user supplies a
+ * pre-shared key directly -- but there is a 4-way handshake
+ * between client and AP to verify that both have the same key
+ * without revealing the contents of that key.
+ */
+ NET80211_SECPROT_PSK = 1,
+
+ /** Full EAP 802.1X handshaking
+ *
+ * This implements the "WPA Enterprise" handshake, connecting
+ * to an 802.1X authentication server to provide credentials
+ * and receive a pairwise master key (PMK), which is then used
+ * in the same 4-way handshake as the PSK method.
+ */
+ NET80211_SECPROT_EAP = 2,
+
+ /** Dummy value used when the handshaking type can't be detected */
+ NET80211_SECPROT_UNKNOWN = 3,
+};
+
+
+/** An 802.11 data encryption algorithm */
+enum net80211_crypto_alg {
+ /** No security, an "Open" network */
+ NET80211_CRYPT_NONE = 0,
+
+ /** Network protected with WEP (awful RC4-based system)
+ *
+ * WEP uses a naive application of RC4, with a monotonically
+ * increasing initialization vector that is prepended to the
+ * key to initialize the RC4 keystream. It is highly insecure
+ * and can be completely cracked or subverted using automated,
+ * robust, freely available tools (aircrack-ng) in minutes.
+ *
+ * 40-bit and 104-bit WEP are differentiated only by the size
+ * of the key. They may be advertised as 64-bit and 128-bit,
+ * counting the non-random IV as part of the key bits.
+ */
+ NET80211_CRYPT_WEP = 1,
+
+ /** Network protected with TKIP (better RC4-based system)
+ *
+ * Usually known by its trade name of WPA (Wi-Fi Protected
+ * Access), TKIP implements a message integrity code (MIC)
+ * called Michael, a timestamp counter for replay prevention,
+ * and a key mixing function that together remove almost all
+ * the security problems with WEP. Countermeasures are
+ * implemented to prevent high data-rate attacks.
+ *
+ * There exists one known attack on TKIP, that allows one to
+ * send between 7 and 15 arbitrary short data packets on a
+ * QoS-enabled network given about an hour of data
+ * gathering. Since gPXE does not support QoS for 802.11
+ * networks, this is not a threat to us. The only other method
+ * is a brute-force passphrase attack.
+ */
+ NET80211_CRYPT_TKIP = 2,
+
+ /** Network protected with CCMP (AES-based system)
+ *
+ * Often called WPA2 in commerce, or RSNA (Robust Security
+ * Network Architecture) in the 802.11 standard, CCMP is
+ * highly secure and does not have any known attack vectors.
+ * Since it is based on a block cipher, the statistical
+ * correlation and "chopchop" attacks used with great success
+ * against WEP and minor success against TKIP fail.
+ */
+ NET80211_CRYPT_CCMP = 3,
+
+ /** Dummy value used when the cryptosystem can't be detected */
+ NET80211_CRYPT_UNKNOWN = 4,
+};
+
+
+/** @defgroup net80211_state Bits for the 802.11 association state field */
+/** @{ */
+
+/** An error code indicating the failure mode, or 0 if successful */
+#define NET80211_STATUS_MASK 0x7F
+
+/** Whether the error code provided is a "reason" code, not a "status" code */
+#define NET80211_IS_REASON 0x80
+
+/** Whether we have found the network we will be associating with */
+#define NET80211_PROBED (1 << 8)
+
+/** Whether we have successfully authenticated with the network
+ *
+ * This usually has nothing to do with actual security; it is a
+ * holdover from older 802.11 implementation ideas.
+ */
+#define NET80211_AUTHENTICATED (1 << 9)
+
+/** Whether we have successfully associated with the network */
+#define NET80211_ASSOCIATED (1 << 10)
+
+/** Whether we have completed security handshaking with the network
+ *
+ * Once this is set, we can send data packets. For that reason this
+ * bit is set even in cases where no security handshaking is
+ * required.
+ */
+#define NET80211_CRYPTO_SYNCED (1 << 11)
+
+/** Whether the auto-association task is running */
+#define NET80211_WORKING (1 << 12)
+
+/** Whether the auto-association task is waiting for a reply from the AP */
+#define NET80211_WAITING (1 << 13)
+
+/** Whether the auto-association task should be suppressed
+ *
+ * This is set by the `iwlist' command so that it can open the device
+ * without starting another probe process that will interfere with its
+ * own.
+ */
+#define NET80211_NO_ASSOC (1 << 14)
+
+/** Whether this association was performed using a broadcast SSID
+ *
+ * If the user opened this device without netX/ssid set, the device's
+ * SSID will be set to that of the network it chooses to associate
+ * with, but the netX/ssid setting will remain blank. If we don't
+ * remember that we started from no specified SSID, it will appear
+ * every time settings are updated (e.g. after DHCP) that we need to
+ * reassociate due to the difference between the set SSID and our own.
+ */
+#define NET80211_AUTO_SSID (1 << 15)
+
+
+/** @} */
+
+
+/** @defgroup net80211_phy 802.11 physical layer flags */
+/** @{ */
+
+/** Whether to use RTS/CTS or CTS-to-self protection for transmissions
+ *
+ * Since the RTS or CTS is transmitted using 802.11b signaling, and
+ * includes a field indicating the amount of time that will be used by
+ * transmission of the following packet, this serves as an effective
+ * protection mechanism to avoid 802.11b clients interfering with
+ * 802.11g clients on mixed networks.
+ */
+#define NET80211_PHY_USE_PROTECTION (1 << 1)
+
+/** Whether to use 802.11b short preamble operation
+ *
+ * Short-preamble operation can moderately increase throughput on
+ * 802.11b networks operating between 2Mbps and 11Mbps. It is
+ * irrelevant for 802.11g data rates, since they use a different
+ * modulation scheme.
+ */
+#define NET80211_PHY_USE_SHORT_PREAMBLE (1 << 2)
+
+/** Whether to use 802.11g short slot operation
+ *
+ * This affects a low-level timing parameter of 802.11g transmissions.
+ */
+#define NET80211_PHY_USE_SHORT_SLOT (1 << 3)
+
+/** @} */
+
+
+/** The maximum number of TX rates we allow to be configured simultaneously */
+#define NET80211_MAX_RATES 16
+
+/** The maximum number of channels we allow to be configured simultaneously */
+#define NET80211_MAX_CHANNELS 32
+
+/** Seconds we'll wait to get all fragments of a packet */
+#define NET80211_FRAG_TIMEOUT 2
+
+/** The number of fragments we can receive at once
+ *
+ * The 802.11 standard requires that this be at least 3.
+ */
+#define NET80211_NR_CONCURRENT_FRAGS 3
+
+/** Maximum TX power to allow (dBm), if we don't get a regulatory hint */
+#define NET80211_REG_TXPOWER 20
+
+
+struct net80211_device;
+
+/** Operations that must be implemented by an 802.11 driver */
+struct net80211_device_operations {
+ /** Open 802.11 device
+ *
+ * @v dev 802.11 device
+ * @ret rc Return status code
+ *
+ * This method should allocate RX I/O buffers and enable the
+ * hardware to start transmitting and receiving packets on the
+ * channels its net80211_register() call indicated it could
+ * handle. It does not need to tune the antenna to receive
+ * packets on any particular channel.
+ */
+ int ( * open ) ( struct net80211_device *dev );
+
+ /** Close 802.11 network device
+ *
+ * @v dev 802.11 device
+ *
+ * This method should stop the flow of packets, and call
+ * net80211_tx_complete() for any packets remaining in the
+ * device's TX queue.
+ */
+ void ( * close ) ( struct net80211_device *dev );
+
+ /** Transmit packet on 802.11 network device
+ *
+ * @v dev 802.11 device
+ * @v iobuf I/O buffer
+ * @ret rc Return status code
+ *
+ * This method should cause the hardware to initiate
+ * transmission of the I/O buffer, using the channel and rate
+ * most recently indicated by an appropriate call to the
+ * @c config callback. The 802.11 layer guarantees that said
+ * channel and rate will be the same as those currently
+ * reflected in the fields of @a dev.
+ *
+ * If this method returns success, the I/O buffer remains
+ * owned by the network layer's TX queue, and the driver must
+ * eventually call net80211_tx_complete() to free the buffer
+ * whether transmission succeeded or not. If this method
+ * returns failure, it will be interpreted as "failure to
+ * enqueue buffer" and the I/O buffer will be immediately
+ * released.
+ *
+ * This method is guaranteed to be called only when the device
+ * is open.
+ */
+ int ( * transmit ) ( struct net80211_device *dev,
+ struct io_buffer *iobuf );
+
+ /** Poll for completed and received packets
+ *
+ * @v dev 802.11 device
+ *
+ * This method should cause the hardware to check for
+ * completed transmissions and received packets. Any received
+ * packets should be delivered via net80211_rx(), and
+ * completed transmissions should be indicated using
+ * net80211_tx_complete().
+ *
+ * This method is guaranteed to be called only when the device
+ * is open.
+ */
+ void ( * poll ) ( struct net80211_device *dev );
+
+ /** Enable or disable interrupts
+ *
+ * @v dev 802.11 device
+ * @v enable If TRUE, interrupts should be enabled
+ */
+ void ( * irq ) ( struct net80211_device *dev, int enable );
+
+ /** Update hardware state to match 802.11 layer state
+ *
+ * @v dev 802.11 device
+ * @v changed Set of flags indicating what may have changed
+ * @ret rc Return status code
+ *
+ * This method should cause the hardware state to be
+ * reinitialized from the state indicated in fields of
+ * net80211_device, in the areas indicated by bits set in
+ * @a changed. If the hardware is unable to do so, this method
+ * may return an appropriate error indication.
+ *
+ * This method is guaranteed to be called only when the device
+ * is open.
+ */
+ int ( * config ) ( struct net80211_device *dev, int changed );
+};
+
+/** An 802.11 RF channel. */
+struct net80211_channel
+{
+ /** The band with which this channel is associated */
+ u8 band;
+
+ /** A channel number interpreted according to the band
+ *
+ * The 2.4GHz band uses channel numbers from 1-13 at 5MHz
+ * intervals such that channel 1 is 2407 MHz; channel 14,
+ * legal for use only in Japan, is defined separately as 2484
+ * MHz. Adjacent channels will overlap, since 802.11
+ * transmissions use a 20 MHz (4-channel) bandwidth. Most
+ * commonly, channels 1, 6, and 11 are used.
+ *
+ * The 5GHz band uses channel numbers derived directly from
+ * the frequency; channel 0 is 5000 MHz, and channels are
+ * always spaced 5 MHz apart. Channel numbers over 180 are
+ * relative to 4GHz instead of 5GHz, but these are rarely
+ * seen. Most channels are not legal for use.
+ */
+ u8 channel_nr;
+
+ /** The center frequency for this channel
+ *
+ * Currently a bandwidth of 20 MHz is assumed.
+ */
+ u16 center_freq;
+
+ /** Hardware channel value */
+ u16 hw_value;
+
+ /** Maximum allowable transmit power, in dBm
+ *
+ * This should be interpreted as EIRP, the power supplied to
+ * an ideal isotropic antenna in order to achieve the same
+ * average signal intensity as the real hardware at a
+ * particular distance.
+ *
+ * Currently no provision is made for directional antennas.
+ */
+ u8 maxpower;
+};
+
+/** Information on the capabilities of an 802.11 hardware device
+ *
+ * In its probe callback, an 802.11 driver must read hardware
+ * registers to determine the appropriate contents of this structure,
+ * fill it, and pass it to net80211_register() so that the 802.11
+ * layer knows how to treat the hardware and what to advertise as
+ * supported to access points.
+ */
+struct net80211_hw_info
+{
+ /** Default hardware MAC address.
+ *
+ * The user may change this by setting the @c netX/mac setting
+ * before the driver's open function is called; in that case
+ * the driver must set the hardware MAC address to the address
+ * contained in the wrapping net_device's ll_addr field, or if
+ * that is impossible, set that ll_addr field back to the
+ * unchangeable hardware MAC address.
+ */
+ u8 hwaddr[ETH_ALEN];
+
+ /** A bitwise OR of the 802.11x modes supported by this device */
+ int modes;
+
+ /** A bitwise OR of the bands on which this device can communicate */
+ int bands;
+
+ /** A set of flags indicating peculiarities of this device. */
+ enum {
+ /** Received frames include a frame check sequence. */
+ NET80211_HW_RX_HAS_FCS = (1 << 1),
+
+ /** Hardware doesn't support 2.4GHz short preambles
+ *
+ * This is only relevant for 802.11b operation above
+ * 2Mbps. All 802.11g devices support short preambles.
+ */
+ NET80211_HW_NO_SHORT_PREAMBLE = (1 << 2),
+
+ /** Hardware doesn't support 802.11g short slot operation */
+ NET80211_HW_NO_SHORT_SLOT = (1 << 3),
+ } flags;
+
+ /** Signal strength information that can be provided by the device
+ *
+ * Signal strength is passed to net80211_rx(), primarily to
+ * allow determination of the closest access point for a
+ * multi-AP network. The units are provided for completeness
+ * of status displays.
+ */
+ enum {
+ /** No signal strength information supported */
+ NET80211_SIGNAL_NONE = 0,
+ /** Signal strength in arbitrary units */
+ NET80211_SIGNAL_ARBITRARY,
+ /** Signal strength in decibels relative to arbitrary base */
+ NET80211_SIGNAL_DB,
+ /** Signal strength in decibels relative to 1mW */
+ NET80211_SIGNAL_DBM,
+ } signal_type;
+
+ /** Maximum signal in arbitrary cases
+ *
+ * If signal_type is NET80211_SIGNAL_ARBITRARY or
+ * NET80211_SIGNAL_DB, the driver should report it on a scale
+ * from 0 to signal_max.
+ */
+ unsigned signal_max;
+
+ /** List of RF channels supported by the card */
+ struct net80211_channel channels[NET80211_MAX_CHANNELS];
+
+ /** Number of supported channels */
+ int nr_channels;
+
+ /** List of transmission rates supported by the card, indexed by band
+ *
+ * Rates should be in 100kbps increments (e.g. 11 Mbps would
+ * be represented as the number 110).
+ */
+ u16 rates[NET80211_NR_BANDS][NET80211_MAX_RATES];
+
+ /** Number of supported rates, indexed by band */
+ int nr_rates[NET80211_NR_BANDS];
+
+ /** Estimate of the time required to change channels, in microseconds
+ *
+ * If this is not known, a guess on the order of a few
+ * milliseconds (value of 1000-5000) is reasonable.
+ */
+ unsigned channel_change_time;
+};
+
+/** Structure tracking received fragments for a packet
+ *
+ * We set up a fragment cache entry when we receive a packet marked as
+ * fragment 0 with the "more fragments" bit set in its frame control
+ * header. We are required by the 802.11 standard to track 3
+ * fragmented packets arriving simultaneously; if we receive more we
+ * may drop some. Upon receipt of a new fragment-0 packet, if no entry
+ * is available or expired, we take over the most @e recent entry for
+ * the new packet, since we don't want to starve old entries from ever
+ * finishing at all. If we get a fragment after the zeroth with no
+ * cache entry for its packet, we drop it.
+ */
+struct net80211_frag_cache
+{
+ /** Whether this cache entry is in use */
+ u8 in_use;
+
+ /** Sequence number of this MSDU (packet) */
+ u16 seqnr;
+
+ /** Timestamp from point at which first fragment was collected */
+ u32 start_ticks;
+
+ /** Buffers for each fragment */
+ struct io_buffer *iob[16];
+};
+
+
+/** Interface to an 802.11 security handshaking protocol
+ *
+ * Security handshaking protocols handle parsing a user-specified key
+ * into a suitable input to the encryption algorithm, and for WPA and
+ * better systems, manage performing whatever authentication with the
+ * network is necessary.
+ *
+ * At all times when any method in this structure is called with a
+ * net80211_device argument @a dev, a dynamically allocated copy of
+ * the handshaker structure itself with space for the requested amount
+ * of private data may be accessed as @c dev->handshaker. The
+ * structure will not be modified, and will only be freed during
+ * reassociation and device closing after the @a stop method has been
+ * called.
+ */
+struct net80211_handshaker
+{
+ /** The security handshaking protocol implemented */
+ enum net80211_security_proto protocol;
+
+ /** Initialize security handshaking protocol
+ *
+ * @v dev 802.11 device
+ * @ret rc Return status code
+ *
+ * This method is expected to access @c netX/key or other
+ * applicable settings to determine the parameters for
+ * handshaking. If no handshaking is required, it should call
+ * sec80211_install() with the cryptosystem and key that are
+ * to be used, and @c start and @c step should be set to @c
+ * NULL.
+ *
+ * This is always called just before association is performed,
+ * but after its parameters have been set; in particular, you
+ * may rely on the contents of the @a essid field in @a dev.
+ */
+ int ( * init ) ( struct net80211_device *dev );
+
+ /** Start handshaking
+ *
+ * @v dev 802.11 device
+ * @ret rc Return status code
+ *
+ * This method is expected to set up internal state so that
+ * packets sent immediately after association, before @a step
+ * can be called, will be handled appropriately.
+ *
+ * This is always called just before association is attempted.
+ */
+ int ( * start ) ( struct net80211_device *dev );
+
+ /** Process handshaking state
+ *
+ * @v dev 802.11 device
+ * @ret rc Return status code, or positive if done
+ *
+ * This method is expected to perform as much progress on the
+ * protocol it implements as is possible without blocking. It
+ * should return 0 if it wishes to be called again, a negative
+ * return status code on error, or a positive value if
+ * handshaking is complete. In the case of a positive return,
+ * net80211_crypto_install() must have been called.
+ *
+ * If handshaking may require further action (e.g. an AP that
+ * might decide to rekey), handlers must be installed by this
+ * function that will act without further calls to @a step.
+ */
+ int ( * step ) ( struct net80211_device *dev );
+
+ /** Change cryptographic key based on setting
+ *
+ * @v dev 802.11 device
+ * @ret rc Return status code
+ *
+ * This method is called whenever the @c netX/key setting
+ * @e may have been changed. It is expected to determine
+ * whether it did in fact change, and if so, to install the
+ * new key using net80211_crypto_install(). If it is not
+ * possible to do this immediately, this method should return
+ * an error; in that case the 802.11 stack will reassociate,
+ * following the usual init/start/step sequence.
+ *
+ * This method is only relevant when it is possible to
+ * associate successfully with an incorrect key. When it is
+ * not, a failed association will be retried until the user
+ * changes the key setting, and a successful association will
+ * not be dropped due to such a change. When association with
+ * an incorrect key is impossible, this function should return
+ * 0 after performing no action.
+ */
+ int ( * change_key ) ( struct net80211_device *dev );
+
+ /** Stop security handshaking handlers
+ *
+ * @v dev 802.11 device
+ *
+ * This method is called just before freeing a security
+ * handshaker; it could, for example, delete a process that @a
+ * start had created to manage the security of the connection.
+ * If not needed it may be set to NULL.
+ */
+ void ( * stop ) ( struct net80211_device *dev );
+
+ /** Amount of private data requested
+ *
+ * Before @c init is called for the first time, this structure's
+ * @c priv pointer will point to this many bytes of allocated
+ * data, where the allocation will be performed separately for
+ * each net80211_device.
+ */
+ int priv_len;
+
+ /** Whether @a start has been called
+ *
+ * Reset to 0 after @a stop is called.
+ */
+ int started;
+
+ /** Pointer to private data
+ *
+ * In initializing this structure statically for a linker
+ * table, set this to NULL.
+ */
+ void *priv;
+};
+
+#define NET80211_HANDSHAKERS __table ( struct net80211_handshaker, \
+ "net80211_handshakers" )
+#define __net80211_handshaker __table_entry ( NET80211_HANDSHAKERS, 01 )
+
+
+/** Interface to an 802.11 cryptosystem
+ *
+ * Cryptosystems define a net80211_crypto structure statically, using
+ * a gPXE linker table to make it available to the 802.11 layer. When
+ * the cryptosystem needs to be used, the 802.11 code will allocate a
+ * copy of the static definition plus whatever space the algorithm has
+ * requested for private state, and point net80211_device::crypto or
+ * net80211_device::gcrypto at it.
+ */
+struct net80211_crypto
+{
+ /** The cryptographic algorithm implemented */
+ enum net80211_crypto_alg algorithm;
+
+ /** Initialize cryptosystem using a given key
+ *
+ * @v crypto 802.11 cryptosystem
+ * @v key Pointer to key bytes
+ * @v keylen Number of key bytes
+ * @v rsc Initial receive sequence counter, if applicable
+ * @ret rc Return status code
+ *
+ * This method is passed the communication key provided by the
+ * security handshake handler, which will already be in the
+ * low-level form required. It may not store a pointer to the
+ * key after returning; it must copy it to its private storage.
+ */
+ int ( * init ) ( struct net80211_crypto *crypto, const void *key,
+ int keylen, const void *rsc );
+
+ /** Encrypt a frame using the cryptosystem
+ *
+ * @v crypto 802.11 cryptosystem
+ * @v iob I/O buffer
+ * @ret eiob Newly allocated I/O buffer with encrypted packet
+ *
+ * This method is called to encrypt a single frame. It is
+ * guaranteed that initialize() will have completed
+ * successfully before this method is called.
+ *
+ * The frame passed already has an 802.11 header prepended,
+ * but the PROTECTED bit in the frame control field will not
+ * be set; this method is responsible for setting it. The
+ * returned I/O buffer should contain a complete copy of @a
+ * iob, including the 802.11 header, but with the PROTECTED
+ * bit set, the data encrypted, and whatever encryption
+ * headers/trailers are necessary added.
+ *
+ * This method should never free the passed I/O buffer.
+ *
+ * Return NULL if the packet could not be encrypted, due to
+ * memory limitations or otherwise.
+ */
+ struct io_buffer * ( * encrypt ) ( struct net80211_crypto *crypto,
+ struct io_buffer *iob );
+
+ /** Decrypt a frame using the cryptosystem
+ *
+ * @v crypto 802.11 cryptosystem
+ * @v eiob Encrypted I/O buffer
+ * @ret iob Newly allocated I/O buffer with decrypted packet
+ *
+ * This method is called to decrypt a single frame. It is
+ * guaranteed that initialize() will have completed
+ * successfully before this method is called.
+ *
+ * Decryption follows the reverse of the pattern used for
+ * encryption: this method must copy the 802.11 header into
+ * the returned packet, decrypt the data stream, remove any
+ * encryption header or trailer, and clear the PROTECTED bit
+ * in the frame control header.
+ *
+ * This method should never free the passed I/O buffer.
+ *
+ * Return NULL if memory was not available for decryption, if
+ * a consistency or integrity check on the decrypted frame
+ * failed, or if the decrypted frame should not be processed
+ * by the network stack for any other reason.
+ */
+ struct io_buffer * ( * decrypt ) ( struct net80211_crypto *crypto,
+ struct io_buffer *iob );
+
+ /** Length of private data requested to be allocated */
+ int priv_len;
+
+ /** Private data for the algorithm to store key and state info */
+ void *priv;
+};
+
+#define NET80211_CRYPTOS __table ( struct net80211_crypto, "net80211_cryptos" )
+#define __net80211_crypto __table_entry ( NET80211_CRYPTOS, 01 )
+
+
+struct net80211_probe_ctx;
+struct net80211_assoc_ctx;
+
+
+/** Structure encapsulating the complete state of an 802.11 device
+ *
+ * An 802.11 device is always wrapped by a network device, and this
+ * network device is always pointed to by the @a netdev field. In
+ * general, operations should never be performed by 802.11 code using
+ * netdev functions directly. It is usually the case that the 802.11
+ * layer might need to do some processing or bookkeeping on top of
+ * what the netdevice code will do.
+ */
+struct net80211_device
+{
+ /** The net_device that wraps us. */
+ struct net_device *netdev;
+
+ /** List of 802.11 devices. */
+ struct list_head list;
+
+ /** 802.11 device operations */
+ struct net80211_device_operations *op;
+
+ /** Driver private data */
+ void *priv;
+
+ /** Information about the hardware, provided to net80211_register() */
+ struct net80211_hw_info *hw;
+
+ /* ---------- Channel and rate fields ---------- */
+
+ /** A list of all possible channels we might use */
+ struct net80211_channel channels[NET80211_MAX_CHANNELS];
+
+ /** The number of channels in the channels array */
+ u8 nr_channels;
+
+ /** The channel currently in use, as an index into the channels array */
+ u8 channel;
+
+ /** A list of all possible TX rates we might use
+ *
+ * Rates are in units of 100 kbps.
+ */
+ u16 rates[NET80211_MAX_RATES];
+
+ /** The number of transmission rates in the rates array */
+ u8 nr_rates;
+
+ /** The rate currently in use, as an index into the rates array */
+ u8 rate;
+
+ /** The rate to use for RTS/CTS transmissions
+ *
+ * This is always the fastest basic rate that is not faster
+ * than the data rate in use. Also an index into the rates array.
+ */
+ u8 rtscts_rate;
+
+ /** Bitmask of basic rates
+ *
+ * If bit N is set in this value, with the LSB considered to
+ * be bit 0, then rate N in the rates array is a "basic" rate.
+ *
+ * We don't decide which rates are "basic"; our AP does, and
+ * we respect its wishes. We need to be able to identify basic
+ * rates in order to calculate the duration of a CTS packet
+ * used for 802.11 g/b interoperability.
+ */
+ u32 basic_rates;
+
+ /* ---------- Association fields ---------- */
+
+ /** The asynchronous association process.
+ *
+ * When an 802.11 netdev is opened, or when the user changes
+ * the SSID setting on an open 802.11 device, an
+ * autoassociation task is started by net80211_autoassocate()
+ * to associate with the new best network. The association is
+ * asynchronous, but no packets can be transmitted until it is
+ * complete. If it is successful, the wrapping net_device is
+ * set as "link up". If it fails, @c assoc_rc will be set with
+ * an error indication.
+ */
+ struct process proc_assoc;
+
+ /** Network with which we are associating
+ *
+ * This will be NULL when we are not actively in the process
+ * of associating with a network we have already successfully
+ * probed for.
+ */
+ struct net80211_wlan *associating;
+
+ /** Context for the association process
+ *
+ * This is a probe_ctx if the @c PROBED flag is not set in @c
+ * state, and an assoc_ctx otherwise.
+ */
+ union {
+ struct net80211_probe_ctx *probe;
+ struct net80211_assoc_ctx *assoc;
+ } ctx;
+
+ /** Security handshaker being used */
+ struct net80211_handshaker *handshaker;
+
+ /** State of our association to the network
+ *
+ * Since the association process happens asynchronously, it's
+ * necessary to have some channel of communication so the
+ * driver can say "I got an association reply and we're OK" or
+ * similar. This variable provides that link. It is a bitmask
+ * of any of NET80211_PROBED, NET80211_AUTHENTICATED,
+ * NET80211_ASSOCIATED, NET80211_CRYPTO_SYNCED to indicate how
+ * far along in associating we are; NET80211_WORKING if the
+ * association task is running; and NET80211_WAITING if a
+ * packet has been sent that we're waiting for a reply to. We
+ * can only be crypto-synced if we're associated, we can
+ * only be associated if we're authenticated, we can only be
+ * authenticated if we've probed.
+ *
+ * If an association process fails (that is, we receive a
+ * packet with an error indication), the error code is copied
+ * into bits 6-0 of this variable and bit 7 is set to specify
+ * what type of error code it is. An AP can provide either a
+ * "status code" (0-51 are defined) explaining why it refused
+ * an association immediately, or a "reason code" (0-45 are
+ * defined) explaining why it canceled an association after it
+ * had originally OK'ed it. Status and reason codes serve
+ * similar functions, but they use separate error message
+ * tables. A gPXE-formatted return status code (negative) is
+ * placed in @c assoc_rc.
+ *
+ * If the failure to associate is indicated by a status code,
+ * the NET80211_IS_REASON bit will be clear; if it is
+ * indicated by a reason code, the bit will be set. If we were
+ * successful, both zero status and zero reason mean success,
+ * so there is no ambiguity.
+ *
+ * To prevent association when opening the device, user code
+ * can set the NET80211_NO_ASSOC bit. The final bit in this
+ * variable, NET80211_AUTO_SSID, is used to remember whether
+ * we picked our SSID through automated probing as opposed to
+ * user specification; the distinction becomes relevant in the
+ * settings applicator.
+ */
+ u16 state;
+
+ /** Return status code associated with @c state */
+ int assoc_rc;
+
+ /** RSN or WPA information element to include with association
+ *
+ * If set to @c NULL, none will be included. It is expected
+ * that this will be set by the @a init function of a security
+ * handshaker if it is needed.
+ */
+ union ieee80211_ie *rsn_ie;
+
+ /* ---------- Parameters of currently associated network ---------- */
+
+ /** 802.11 cryptosystem for our current network
+ *
+ * For an open network, this will be set to NULL.
+ */
+ struct net80211_crypto *crypto;
+
+ /** 802.11 cryptosystem for multicast and broadcast frames
+ *
+ * If this is NULL, the cryptosystem used for receiving
+ * unicast frames will also be used for receiving multicast
+ * and broadcast frames. Transmitted multicast and broadcast
+ * frames are always sent unicast to the AP, who multicasts
+ * them on our behalf; thus they always use the unicast
+ * cryptosystem.
+ */
+ struct net80211_crypto *gcrypto;
+
+ /** MAC address of the access point most recently associated */
+ u8 bssid[ETH_ALEN];
+
+ /** SSID of the access point we are or will be associated with
+ *
+ * Although the SSID field in 802.11 packets is generally not
+ * NUL-terminated, here and in net80211_wlan we add a NUL for
+ * convenience.
+ */
+ char essid[IEEE80211_MAX_SSID_LEN+1];
+
+ /** Association ID given to us by the AP */
+ u16 aid;
+
+ /** TSFT value for last beacon received, microseconds */
+ u64 last_beacon_timestamp;
+
+ /** Time between AP sending beacons, microseconds */
+ u32 tx_beacon_interval;
+
+ /** Smoothed average time between beacons, microseconds */
+ u32 rx_beacon_interval;
+
+ /* ---------- Physical layer information ---------- */
+
+ /** Physical layer options
+ *
+ * These control the use of CTS protection, short preambles,
+ * and short-slot operation.
+ */
+ int phy_flags;
+
+ /** Signal strength of last received packet */
+ int last_signal;
+
+ /** Rate control state */
+ struct rc80211_ctx *rctl;
+
+ /* ---------- Packet handling state ---------- */
+
+ /** Fragment reassembly state */
+ struct net80211_frag_cache frags[NET80211_NR_CONCURRENT_FRAGS];
+
+ /** The sequence number of the last packet we sent */
+ u16 last_tx_seqnr;
+
+ /** Packet duplication elimination state
+ *
+ * We are only required to handle immediate duplicates for
+ * each direct sender, and since we can only have one direct
+ * sender (the AP), we need only keep the sequence control
+ * field from the most recent packet we've received. Thus,
+ * this field stores the last sequence control field we've
+ * received for a packet from the AP.
+ */
+ u16 last_rx_seq;
+
+ /** RX management packet queue
+ *
+ * Sometimes we want to keep probe, beacon, and action packets
+ * that we receive, such as when we're scanning for networks.
+ * Ordinarily we drop them because they are sent at a large
+ * volume (ten beacons per second per AP, broadcast) and we
+ * have no need of them except when we're scanning.
+ *
+ * When keep_mgmt is TRUE, received probe, beacon, and action
+ * management packets will be stored in this queue.
+ */
+ struct list_head mgmt_queue;
+
+ /** RX management packet info queue
+ *
+ * We need to keep track of the signal strength for management
+ * packets we're keeping, because that provides the only way
+ * to distinguish between multiple APs for the same network.
+ * Since we can't extend io_buffer to store signal, this field
+ * heads a linked list of "RX packet info" structures that
+ * contain that signal strength field. Its entries always
+ * parallel the entries in mgmt_queue, because the two queues
+ * are always added to or removed from in parallel.
+ */
+ struct list_head mgmt_info_queue;
+
+ /** Whether to store management packets
+ *
+ * Received beacon, probe, and action packets will be added to
+ * mgmt_queue (and their signal strengths added to
+ * mgmt_info_queue) only when this variable is TRUE. It should
+ * be set by net80211_keep_mgmt() (which returns the old
+ * value) only when calling code is prepared to poll the
+ * management queue frequently, because packets will otherwise
+ * pile up and exhaust memory.
+ */
+ int keep_mgmt;
+};
+
+/** Structure representing a probed network.
+ *
+ * This is returned from the net80211_probe_finish functions and
+ * passed to the low-level association functions. At least essid,
+ * bssid, channel, beacon, and security must be filled in if you want
+ * to build this structure manually.
+ */
+struct net80211_wlan
+{
+ /** The human-readable ESSID (network name)
+ *
+ * Although the 802.11 SSID field is generally not
+ * NUL-terminated, the gPXE code adds an extra NUL (and
+ * expects one in this structure) for convenience.
+ */
+ char essid[IEEE80211_MAX_SSID_LEN+1];
+
+ /** MAC address of the strongest-signal access point for this ESSID */
+ u8 bssid[ETH_ALEN];
+
+ /** Signal strength of beacon frame from that access point */
+ int signal;
+
+ /** The channel on which that access point communicates
+ *
+ * This is a raw channel number (net80211_channel::channel_nr),
+ * so that it will not be affected by reconfiguration of the
+ * device channels array.
+ */
+ int channel;
+
+ /** The complete beacon or probe-response frame received */
+ struct io_buffer *beacon;
+
+ /** Security handshaking method used on the network */
+ enum net80211_security_proto handshaking;
+
+ /** Cryptographic algorithm used on the network */
+ enum net80211_crypto_alg crypto;
+
+ /** Link to allow chaining multiple structures into a list to
+ be returned from net80211_probe_finish_all(). */
+ struct list_head list;
+};
+
+
+/** 802.11 encryption key setting */
+extern struct setting net80211_key_setting __setting;
+
+
+/**
+ * @defgroup net80211_probe 802.11 network location API
+ * @{
+ */
+int net80211_prepare_probe ( struct net80211_device *dev, int band,
+ int active );
+struct net80211_probe_ctx * net80211_probe_start ( struct net80211_device *dev,
+ const char *essid,
+ int active );
+int net80211_probe_step ( struct net80211_probe_ctx *ctx );
+struct net80211_wlan *
+net80211_probe_finish_best ( struct net80211_probe_ctx *ctx );
+struct list_head *net80211_probe_finish_all ( struct net80211_probe_ctx *ctx );
+
+void net80211_free_wlan ( struct net80211_wlan *wlan );
+void net80211_free_wlanlist ( struct list_head *list );
+/** @} */
+
+
+/**
+ * @defgroup net80211_mgmt 802.11 network management API
+ * @{
+ */
+struct net80211_device * net80211_get ( struct net_device *netdev );
+void net80211_autoassociate ( struct net80211_device *dev );
+
+int net80211_change_channel ( struct net80211_device *dev, int channel );
+void net80211_set_rate_idx ( struct net80211_device *dev, int rate );
+
+int net80211_keep_mgmt ( struct net80211_device *dev, int enable );
+struct io_buffer * net80211_mgmt_dequeue ( struct net80211_device *dev,
+ int *signal );
+int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc,
+ u8 bssid[ETH_ALEN], struct io_buffer *iob );
+/** @} */
+
+
+/**
+ * @defgroup net80211_assoc 802.11 network association API
+ * @{
+ */
+int net80211_prepare_assoc ( struct net80211_device *dev,
+ struct net80211_wlan *wlan );
+int net80211_send_auth ( struct net80211_device *dev,
+ struct net80211_wlan *wlan, int method );
+int net80211_send_assoc ( struct net80211_device *dev,
+ struct net80211_wlan *wlan );
+void net80211_deauthenticate ( struct net80211_device *dev, int rc );
+/** @} */
+
+
+/**
+ * @defgroup net80211_driver 802.11 driver interface API
+ * @{
+ */
+struct net80211_device *net80211_alloc ( size_t priv_size );
+int net80211_register ( struct net80211_device *dev,
+ struct net80211_device_operations *ops,
+ struct net80211_hw_info *hw );
+u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate );
+void net80211_rx ( struct net80211_device *dev, struct io_buffer *iob,
+ int signal, u16 rate );
+void net80211_rx_err ( struct net80211_device *dev,
+ struct io_buffer *iob, int rc );
+void net80211_tx_complete ( struct net80211_device *dev,
+ struct io_buffer *iob, int retries, int rc );
+void net80211_unregister ( struct net80211_device *dev );
+void net80211_free ( struct net80211_device *dev );
+/** @} */
+
+/**
+ * Calculate duration field for a CTS control frame
+ *
+ * @v dev 802.11 device
+ * @v size Size of the packet being cleared to send
+ *
+ * A CTS control frame's duration field captures the frame being
+ * protected and its 10-byte ACK.
+ */
+static inline u16 net80211_cts_duration ( struct net80211_device *dev,
+ int size )
+{
+ return ( net80211_duration ( dev, 10,
+ dev->rates[dev->rtscts_rate] ) +
+ net80211_duration ( dev, size, dev->rates[dev->rate] ) );
+}
+
+#endif