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opengnsys_ipxe/src/net/80211/net80211.c

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/*
* The gPXE 802.11 MAC layer.
*
* Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
*
* 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 <string.h>
#include <byteswap.h>
#include <stdlib.h>
#include <gpxe/settings.h>
#include <gpxe/if_arp.h>
#include <gpxe/ethernet.h>
#include <gpxe/ieee80211.h>
#include <gpxe/netdevice.h>
#include <gpxe/net80211.h>
#include <gpxe/timer.h>
#include <gpxe/nap.h>
#include <unistd.h>
#include <errno.h>
/** @file
*
* 802.11 device management
*/
/* Disambiguate the EINVAL's a bit */
#define EINVAL_PKT_TOO_SHORT ( EINVAL | EUNIQ_01 )
#define EINVAL_PKT_VERSION ( EINVAL | EUNIQ_02 )
#define EINVAL_PKT_NOT_DATA ( EINVAL | EUNIQ_03 )
#define EINVAL_PKT_NOT_FROMDS ( EINVAL | EUNIQ_04 )
#define EINVAL_PKT_LLC_HEADER ( EINVAL | EUNIQ_05 )
#define EINVAL_CRYPTO_REQUEST ( EINVAL | EUNIQ_06 )
#define EINVAL_ACTIVE_SCAN ( EINVAL | EUNIQ_07 )
/*
* 802.11 error codes: The AP can give us a status code explaining why
* authentication failed, or a reason code explaining why we were
* deauthenticated/disassociated. These codes range from 0-63 (the
* field is 16 bits wide, but only up to 45 or so are defined yet; we
* allow up to 63 for extensibility). This is encoded into an error
* code as such:
*
* status & 0x1f goes here --vv--
* Status code 0-31: ECONNREFUSED | EUNIQ_(status & 0x1f) (0e1a6038)
* Status code 32-63: EHOSTUNREACH | EUNIQ_(status & 0x1f) (171a6011)
* Reason code 0-31: ECONNRESET | EUNIQ_(reason & 0x1f) (0f1a6039)
* Reason code 32-63: ENETRESET | EUNIQ_(reason & 0x1f) (271a6001)
*
* The POSIX error codes more or less convey the appropriate message
* (status codes occur when we can't associate at all, reason codes
* when we lose association unexpectedly) and let us extract the
* complete 802.11 error code from the rc value.
*/
/** Make return status code from 802.11 status code */
#define E80211_STATUS( stat ) ( ((stat & 0x20)? EHOSTUNREACH : ECONNREFUSED) \
| ((stat & 0x1f) << 8) )
/** Make return status code from 802.11 reason code */
#define E80211_REASON( reas ) ( ((reas & 0x20)? ENETRESET : ECONNRESET) \
| ((reas & 0x1f) << 8) )
/** List of 802.11 devices */
static struct list_head net80211_devices = LIST_HEAD_INIT ( net80211_devices );
/** Set of device operations that does nothing */
static struct net80211_device_operations net80211_null_ops;
/** Information associated with a received management packet
*
* This is used to keep beacon signal strengths in a parallel queue to
* the beacons themselves.
*/
struct net80211_rx_info {
int signal;
struct list_head list;
};
/** Context for a probe operation */
struct net80211_probe_ctx {
/** 802.11 device to probe on */
struct net80211_device *dev;
/** Value of keep_mgmt before probe was started */
int old_keep_mgmt;
/** If scanning actively, pointer to probe packet to send */
struct io_buffer *probe;
/** If non-"", the ESSID to limit ourselves to */
const char *essid;
/** Time probe was started */
u32 ticks_start;
/** Time last useful beacon was received */
u32 ticks_beacon;
/** Time channel was last changed */
u32 ticks_channel;
/** Time to stay on each channel */
u32 hop_time;
/** Channels to hop by when changing channel */
int hop_step;
/** List of best beacons for each network found so far */
struct list_head *beacons;
};
/** Context for the association task */
struct net80211_assoc_ctx {
/** Next authentication method to try using */
int method;
/** Time (in ticks) of the last sent association-related packet */
int last_packet;
/** Number of times we have tried sending it */
int times_tried;
};
/**
* @defgroup net80211_netdev Network device interface functions
* @{
*/
static int net80211_netdev_open ( struct net_device *netdev );
static void net80211_netdev_close ( struct net_device *netdev );
static int net80211_netdev_transmit ( struct net_device *netdev,
struct io_buffer *iobuf );
static void net80211_netdev_poll ( struct net_device *netdev );
static void net80211_netdev_irq ( struct net_device *netdev, int enable );
/** @} */
/**
* @defgroup net80211_linklayer 802.11 link-layer protocol functions
* @{
*/
static int net80211_ll_push ( struct net_device *netdev,
struct io_buffer *iobuf, const void *ll_dest,
const void *ll_source, uint16_t net_proto );
static int net80211_ll_pull ( struct net_device *netdev,
struct io_buffer *iobuf, const void **ll_dest,
const void **ll_source, uint16_t * net_proto );
static int net80211_ll_mc_hash ( unsigned int af, const void *net_addr,
void *ll_addr );
/** @} */
/**
* @defgroup net80211_help 802.11 helper functions
* @{
*/
static void net80211_add_channels ( struct net80211_device *dev, int start,
int len, int txpower );
static void net80211_filter_hw_channels ( struct net80211_device *dev );
static void net80211_set_rtscts_rate ( struct net80211_device *dev );
static int net80211_process_capab ( struct net80211_device *dev,
u16 capab );
static int net80211_process_ie ( struct net80211_device *dev,
union ieee80211_ie *ie, void *ie_end );
static union ieee80211_ie *
net80211_marshal_request_info ( struct net80211_device *dev,
union ieee80211_ie *ie );
/** @} */
/**
* @defgroup net80211_assoc_ll 802.11 association handling functions
* @{
*/
static void net80211_step_associate ( struct process *proc );
static void net80211_handle_auth ( struct net80211_device *dev,
struct io_buffer *iob );
static void net80211_handle_assoc_reply ( struct net80211_device *dev,
struct io_buffer *iob );
static int net80211_send_disassoc ( struct net80211_device *dev, int reason );
static void net80211_handle_mgmt ( struct net80211_device *dev,
struct io_buffer *iob, int signal );
/** @} */
/**
* @defgroup net80211_frag 802.11 fragment handling functions
* @{
*/
static void net80211_free_frags ( struct net80211_device *dev, int fcid );
static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
int fcid, int nfrags, int size );
static void net80211_rx_frag ( struct net80211_device *dev,
struct io_buffer *iob, int signal );
/** @} */
/**
* @defgroup net80211_settings 802.11 settings handlers
* @{
*/
static int net80211_check_ssid_update ( void );
/** 802.11 settings applicator
*
* When the SSID is changed, this will cause any open devices to
* re-associate.
*/
struct settings_applicator net80211_ssid_applicator __settings_applicator = {
.apply = net80211_check_ssid_update,
};
/** The network name to associate with
*
* If this is blank, we scan for all networks and use the one with the
* greatest signal strength.
*/
struct setting net80211_ssid_setting __setting = {
.name = "ssid",
.description = "802.11 SSID (network name)",
.type = &setting_type_string,
};
/** Whether to use active scanning
*
* In order to associate with a hidden SSID, it's necessary to use an
* active scan (send probe packets). If this setting is nonzero, an
* active scan on the 2.4GHz band will be used to associate.
*/
struct setting net80211_active_setting __setting = {
.name = "active-scan",
.description = "Use an active scan during 802.11 association",
.type = &setting_type_int8,
};
/** @} */
/* ---------- net_device wrapper ---------- */
/**
* Open 802.11 device and start association
*
* @v netdev Wrapping network device
* @ret rc Return status code
*
* This sets up a default conservative set of channels for probing,
* and starts the auto-association task unless the @c
* NET80211_NO_ASSOC flag is set in the wrapped 802.11 device's @c
* state field.
*/
static int net80211_netdev_open ( struct net_device *netdev )
{
struct net80211_device *dev = netdev->priv;
int rc = 0;
if ( dev->op == &net80211_null_ops )
return -EFAULT;
if ( dev->op->open )
rc = dev->op->open ( dev );
if ( rc < 0 )
return rc;
if ( ! ( dev->state & NET80211_NO_ASSOC ) )
net80211_autoassociate ( dev );
return 0;
}
/**
* Close 802.11 device
*
* @v netdev Wrapping network device.
*
* If the association task is running, this will stop it.
*/
static void net80211_netdev_close ( struct net_device *netdev )
{
struct net80211_device *dev = netdev->priv;
if ( dev->state & NET80211_WORKING )
process_del ( &dev->proc_assoc );
/* Send disassociation frame to AP, to be polite */
if ( dev->state & NET80211_ASSOCIATED )
net80211_send_disassoc ( dev, IEEE80211_REASON_LEAVING );
netdev_link_down ( netdev );
dev->state = 0;
if ( dev->op->close )
dev->op->close ( dev );
}
/**
* Transmit packet on 802.11 device
*
* @v netdev Wrapping network device
* @v iobuf I/O buffer
* @ret rc Return status code
*
* If encryption is enabled for the currently associated network, the
* packet will be encrypted prior to transmission.
*/
static int net80211_netdev_transmit ( struct net_device *netdev,
struct io_buffer *iobuf )
{
struct net80211_device *dev = netdev->priv;
int rc = -ENOSYS;
if ( dev->crypto ) {
struct io_buffer *niob = dev->crypto->encrypt ( dev->crypto,
iobuf );
if ( ! niob )
return -ENOMEM; /* only reason encryption could fail */
free_iob ( iobuf );
iobuf = niob;
}
if ( dev->op->transmit )
rc = dev->op->transmit ( dev, iobuf );
return rc;
}
/**
* Poll 802.11 device for received packets and completed transmissions
*
* @v netdev Wrapping network device
*/
static void net80211_netdev_poll ( struct net_device *netdev )
{
struct net80211_device *dev = netdev->priv;
if ( dev->op->poll )
dev->op->poll ( dev );
}
/**
* Enable or disable interrupts for 802.11 device
*
* @v netdev Wrapping network device
* @v enable Whether to enable interrupts
*/
static void net80211_netdev_irq ( struct net_device *netdev, int enable )
{
struct net80211_device *dev = netdev->priv;
if ( dev->op->irq )
dev->op->irq ( dev, enable );
}
/** Network device operations for a wrapped 802.11 device */
static struct net_device_operations net80211_netdev_ops = {
.open = net80211_netdev_open,
.close = net80211_netdev_close,
.transmit = net80211_netdev_transmit,
.poll = net80211_netdev_poll,
.irq = net80211_netdev_irq,
};
/* ---------- 802.11 link-layer protocol ---------- */
/** 802.11 broadcast MAC address */
static u8 net80211_ll_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
/**
* Determine whether a transmission rate uses ERP/OFDM
*
* @v rate Rate in 100 kbps units
* @ret is_erp TRUE if the rate is an ERP/OFDM rate
*
* 802.11b supports rates of 1.0, 2.0, 5.5, and 11.0 Mbps; any other
* rate than these on the 2.4GHz spectrum is an ERP (802.11g) rate.
*/
static inline int net80211_rate_is_erp ( u16 rate )
{
if ( rate == 10 || rate == 20 || rate == 55 || rate == 110 )
return 0;
return 1;
}
/**
* Calculate one frame's contribution to 802.11 duration field
*
* @v dev 802.11 device
* @v bytes Amount of data to calculate duration for
* @ret dur Duration field in microseconds
*
* To avoid multiple stations attempting to transmit at once, 802.11
* provides that every packet shall include a duration field
* specifying a length of time for which the wireless medium will be
* reserved after it is transmitted. The duration is measured in
* microseconds and is calculated with respect to the current
* physical-layer parameters of the 802.11 device.
*
* For an unfragmented data or management frame, or the last fragment
* of a fragmented frame, the duration captures only the 10 data bytes
* of one ACK; call once with bytes = 10.
*
* For a fragment of a data or management rame that will be followed
* by more fragments, the duration captures an ACK, the following
* fragment, and its ACK; add the results of three calls, two with
* bytes = 10 and one with bytes set to the next fragment's size.
*
* For an RTS control frame, the duration captures the responding CTS,
* the frame being sent, and its ACK; add the results of three calls,
* two with bytes = 10 and one with bytes set to the next frame's size
* (assuming unfragmented).
*
* For a CTS-to-self control frame, the duration captures the frame
* being protected and its ACK; add the results of two calls, one with
* bytes = 10 and one with bytes set to the next frame's size.
*
* No other frame types are currently supported by gPXE.
*/
u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate )
{
struct net80211_channel *chan = &dev->channels[dev->channel];
u32 kbps = rate * 100;
if ( chan->band == NET80211_BAND_5GHZ || net80211_rate_is_erp ( rate ) ) {
/* OFDM encoding (802.11a/g) */
int bits_per_symbol = ( kbps * 4 ) / 1000; /* 4us/symbol */
int bits = 22 + ( bytes << 3 ); /* 22-bit PLCP */
int symbols = ( bits + bits_per_symbol - 1 ) / bits_per_symbol;
return 16 + 20 + ( symbols * 4 ); /* 16us SIFS, 20us preamble */
} else {
/* CCK encoding (802.11b) */
int phy_time = 144 + 48; /* preamble + PLCP */
int bits = bytes << 3;
int data_time = ( bits * 1000 + kbps - 1 ) / kbps;
if ( dev->phy_flags & NET80211_PHY_USE_SHORT_PREAMBLE )
phy_time >>= 1;
return 10 + phy_time + data_time; /* 10us SIFS */
}
}
/**
* Add 802.11 link-layer header
*
* @v netdev Wrapping network device
* @v iobuf I/O buffer
* @v ll_dest Link-layer destination address
* @v ll_source Link-layer source address
* @v net_proto Network-layer protocol, in network byte order
* @ret rc Return status code
*
* This adds both the 802.11 frame header and the 802.2 LLC/SNAP
* header used on data packets.
*
* We also check here for state of the link that would make it invalid
* to send a data packet; every data packet must pass through here,
* and no non-data packet (e.g. management frame) should.
*/
static int net80211_ll_push ( struct net_device *netdev,
struct io_buffer *iobuf, const void *ll_dest,
const void *ll_source, uint16_t net_proto )
{
struct net80211_device *dev = netdev->priv;
struct ieee80211_frame *hdr = iob_push ( iobuf,
IEEE80211_LLC_HEADER_LEN +
IEEE80211_TYP_FRAME_HEADER_LEN );
struct ieee80211_llc_snap_header *lhdr =
( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
/* We can't send data packets if we're not associated. */
if ( ! netdev_link_ok ( netdev ) ) {
if ( dev->assoc_rc )
return dev->assoc_rc;
return -ENETUNREACH;
}
hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_DATA |
IEEE80211_STYPE_DATA | IEEE80211_FC_TODS;
/* We don't send fragmented frames, so duration is the time
for an SIFS + 10-byte ACK. */
hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
memcpy ( hdr->addr1, dev->bssid, ETH_ALEN );
memcpy ( hdr->addr2, ll_source, ETH_ALEN );
memcpy ( hdr->addr3, ll_dest, ETH_ALEN );
hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
lhdr->dsap = IEEE80211_LLC_DSAP;
lhdr->ssap = IEEE80211_LLC_SSAP;
lhdr->ctrl = IEEE80211_LLC_CTRL;
memset ( lhdr->oui, 0x00, 3 );
lhdr->ethertype = net_proto;
return 0;
}
/**
* Remove 802.11 link-layer header
*
* @v netdev Wrapping network device
* @v iobuf I/O buffer
* @ret ll_dest Link-layer destination address
* @ret ll_source Link-layer source
* @ret net_proto Network-layer protocol, in network byte order
* @ret rc Return status code
*
* This expects and removes both the 802.11 frame header and the 802.2
* LLC/SNAP header that are used on data packets.
*/
static int net80211_ll_pull ( struct net_device *netdev __unused,
struct io_buffer *iobuf,
const void **ll_dest, const void **ll_source,
uint16_t * net_proto )
{
struct ieee80211_frame *hdr = iobuf->data;
struct ieee80211_llc_snap_header *lhdr =
( void * ) hdr + IEEE80211_TYP_FRAME_HEADER_LEN;
/* Bunch of sanity checks */
if ( iob_len ( iobuf ) < IEEE80211_TYP_FRAME_HEADER_LEN +
IEEE80211_LLC_HEADER_LEN ) {
DBGC ( netdev->priv, "802.11 %p packet too short (%zd bytes)\n",
netdev->priv, iob_len ( iobuf ) );
return -EINVAL_PKT_TOO_SHORT;
}
if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION ) {
DBGC ( netdev->priv, "802.11 %p packet invalid version %04x\n",
netdev->priv, hdr->fc & IEEE80211_FC_VERSION );
return -EINVAL_PKT_VERSION;
}
if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_DATA ||
( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA ) {
DBGC ( netdev->priv, "802.11 %p packet not data/data (fc=%04x)\n",
netdev->priv, hdr->fc );
return -EINVAL_PKT_NOT_DATA;
}
if ( ( hdr->fc & ( IEEE80211_FC_TODS | IEEE80211_FC_FROMDS ) ) !=
IEEE80211_FC_FROMDS ) {
DBGC ( netdev->priv, "802.11 %p packet not from DS (fc=%04x)\n",
netdev->priv, hdr->fc );
return -EINVAL_PKT_NOT_FROMDS;
}
if ( lhdr->dsap != IEEE80211_LLC_DSAP || lhdr->ssap != IEEE80211_LLC_SSAP ||
lhdr->ctrl != IEEE80211_LLC_CTRL || lhdr->oui[0] || lhdr->oui[1] ||
lhdr->oui[2] ) {
DBGC ( netdev->priv, "802.11 %p LLC header is not plain EtherType "
"encapsulator: %02x->%02x [%02x] %02x:%02x:%02x %04x\n",
netdev->priv, lhdr->dsap, lhdr->ssap, lhdr->ctrl,
lhdr->oui[0], lhdr->oui[1], lhdr->oui[2], lhdr->ethertype );
return -EINVAL_PKT_LLC_HEADER;
}
iob_pull ( iobuf, sizeof ( *hdr ) + sizeof ( *lhdr ) );
*ll_dest = hdr->addr1;
*ll_source = hdr->addr3;
*net_proto = lhdr->ethertype;
return 0;
}
/**
* Hash 802.11 multicast address
*
* @v af Address family
* @v net_addr Network-layer address
* @ret ll_addr Filled link-layer address
* @ret rc Return status code
*
* Currently unimplemented.
*/
static int net80211_ll_mc_hash ( unsigned int af __unused,
const void *net_addr __unused,
void *ll_addr __unused )
{
return -ENOTSUP;
}
/** 802.11 link-layer protocol */
static struct ll_protocol net80211_ll_protocol __ll_protocol = {
.name = "802.11",
.push = net80211_ll_push,
.pull = net80211_ll_pull,
.init_addr = eth_init_addr,
.ntoa = eth_ntoa,
.mc_hash = net80211_ll_mc_hash,
.ll_proto = htons ( ARPHRD_ETHER ), /* "encapsulated Ethernet" */
.hw_addr_len = ETH_ALEN,
.ll_addr_len = ETH_ALEN,
.ll_header_len = IEEE80211_TYP_FRAME_HEADER_LEN +
IEEE80211_LLC_HEADER_LEN,
};
/* ---------- 802.11 network management API ---------- */
/**
* Get 802.11 device from wrapping network device
*
* @v netdev Wrapping network device
* @ret dev 802.11 device wrapped by network device, or NULL
*
* Returns NULL if the network device does not wrap an 802.11 device.
*/
struct net80211_device * net80211_get ( struct net_device *netdev )
{
struct net80211_device *dev;
list_for_each_entry ( dev, &net80211_devices, list ) {
if ( netdev->priv == dev )
return netdev->priv;
}
return NULL;
}
/**
* Set state of 802.11 device keeping management frames
*
* @v dev 802.11 device
* @v enable Whether to keep management frames
* @ret oldenab Whether management frames were enabled before this call
*
* If enable is TRUE, beacon, probe, and action frames will be kept
* and may be retrieved by calling net80211_mgmt_dequeue().
*/
int net80211_keep_mgmt ( struct net80211_device *dev, int enable )
{
int oldenab = dev->keep_mgmt;
dev->keep_mgmt = enable;
return oldenab;
}
/**
* Get 802.11 management frame
*
* @v dev 802.11 device
* @ret signal Signal strength of returned management frame
* @ret iob I/O buffer, or NULL if no management frame is queued
*
* Frames will only be returned by this function if
* net80211_keep_mgmt() has been previously called with enable set to
* TRUE.
*
* The calling function takes ownership of the returned I/O buffer.
*/
struct io_buffer * net80211_mgmt_dequeue ( struct net80211_device *dev,
int *signal )
{
struct io_buffer *iobuf;
struct net80211_rx_info *rxi;
list_for_each_entry ( rxi, &dev->mgmt_info_queue, list ) {
list_del ( &rxi->list );
if ( signal )
*signal = rxi->signal;
free ( rxi );
list_for_each_entry ( iobuf, &dev->mgmt_queue, list ) {
list_del ( &iobuf->list );
return iobuf;
}
assert ( 0 );
}
return NULL;
}
/**
* Transmit 802.11 management frame
*
* @v dev 802.11 device
* @v fc Frame Control flags for management frame
* @v dest Destination access point
* @v iob I/O buffer
* @ret rc Return status code
*
* The @a fc argument must contain at least an IEEE 802.11 management
* subtype number (e.g. IEEE80211_STYPE_PROBE_REQ). If it contains
* IEEE80211_FC_PROTECTED, the frame will be encrypted prior to
* transmission.
*
* It is required that @a iob have at least 24 bytes of headroom
* reserved before its data start.
*/
int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc, u8 dest[6],
struct io_buffer *iob )
{
struct ieee80211_frame *hdr = iob_push ( iob,
IEEE80211_TYP_FRAME_HEADER_LEN );
hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_MGMT |
( fc & ~IEEE80211_FC_PROTECTED );
hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
memcpy ( hdr->addr1, dest, ETH_ALEN ); /* DA = RA */
memcpy ( hdr->addr2, dev->netdev->ll_addr, ETH_ALEN ); /* SA = TA */
memcpy ( hdr->addr3, dest, ETH_ALEN ); /* BSSID */
if ( fc & IEEE80211_FC_PROTECTED ) {
if ( ! dev->crypto )
return -EINVAL_CRYPTO_REQUEST;
struct io_buffer *eiob = dev->crypto->encrypt ( dev->crypto,
iob );
free_iob ( iob );
iob = eiob;
}
return netdev_tx ( dev->netdev, iob );
}
/* ---------- Driver API ---------- */
/**
* Allocate 802.11 device
*
* @v priv_size Size of driver-private allocation area
* @ret dev Newly allocated 802.11 device
*
* This function allocates a net_device with space in its private area
* for both the net80211_device it will wrap and the driver-private
* data space requested. It initializes the link-layer-specific parts
* of the net_device, and links the net80211_device to the net_device
* appropriately.
*/
struct net80211_device * net80211_alloc ( size_t priv_size )
{
struct net80211_device *dev;
struct net_device *netdev =
alloc_netdev ( sizeof ( *dev ) + priv_size );
if ( ! netdev )
return NULL;
netdev->ll_protocol = &net80211_ll_protocol;
netdev->ll_broadcast = net80211_ll_broadcast;
netdev->max_pkt_len = IEEE80211_MAX_DATA_LEN;
netdev_init ( netdev, &net80211_netdev_ops );
dev = netdev->priv;
dev->netdev = netdev;
dev->priv = ( u8 * ) dev + sizeof ( *dev );
dev->op = &net80211_null_ops;
process_init_stopped ( &dev->proc_assoc, net80211_step_associate,
&netdev->refcnt );
INIT_LIST_HEAD ( &dev->mgmt_queue );
INIT_LIST_HEAD ( &dev->mgmt_info_queue );
return dev;
}
/**
* Register 802.11 device with network stack
*
* @v dev 802.11 device
* @v ops 802.11 device operations
* @v hw 802.11 hardware information
*
* This also registers the wrapping net_device with the higher network
* layers.
*/
int net80211_register ( struct net80211_device *dev,
struct net80211_device_operations *ops,
struct net80211_hw_info *hw )
{
dev->op = ops;
dev->hw = malloc ( sizeof ( *hw ) );
if ( ! dev->hw )
return -ENOMEM;
memcpy ( dev->hw, hw, sizeof ( *hw ) );
memcpy ( dev->netdev->hw_addr, hw->hwaddr, ETH_ALEN );
/* Set some sensible channel defaults for driver's open() function */
memcpy ( dev->channels, dev->hw->channels,
NET80211_MAX_CHANNELS * sizeof ( dev->channels[0] ) );
dev->channel = 0;
list_add_tail ( &dev->list, &net80211_devices );
return register_netdev ( dev->netdev );
}
/**
* Unregister 802.11 device from network stack
*
* @v dev 802.11 device
*
* After this call, the device operations are cleared so that they
* will not be called.
*/
void net80211_unregister ( struct net80211_device *dev )
{
unregister_netdev ( dev->netdev );
list_del ( &dev->list );
dev->op = &net80211_null_ops;
}
/**
* Free 802.11 device
*
* @v dev 802.11 device
*
* The device should be unregistered before this function is called.
*/
void net80211_free ( struct net80211_device *dev )
{
free ( dev->hw );
rc80211_free ( dev->rctl );
netdev_nullify ( dev->netdev );
netdev_put ( dev->netdev );
}
/* ---------- 802.11 network management workhorse code ---------- */
/**
* Set state of 802.11 device
*
* @v dev 802.11 device
* @v clear Bitmask of flags to clear
* @v set Bitmask of flags to set
* @v status Status or reason code for most recent operation
*
* If @a status represents a reason code, it should be OR'ed with
* NET80211_IS_REASON.
*
* Clearing authentication also clears association; clearing
* association also clears security handshaking state. Clearing
* association removes the link-up flag from the wrapping net_device,
* but setting it does not automatically set the flag; that is left to
* the judgment of higher-level code.
*/
static inline void net80211_set_state ( struct net80211_device *dev,
short clear, short set,
u16 status )
{
/* The conditions in this function are deliberately formulated
to be decidable at compile-time in most cases. Since clear
and set are generally passed as constants, the body of this
function can be reduced down to a few statements by the
compiler. */
const int statmsk = NET80211_STATUS_MASK | NET80211_IS_REASON;
if ( clear & NET80211_PROBED )
clear |= NET80211_AUTHENTICATED;
if ( clear & NET80211_AUTHENTICATED )
clear |= NET80211_ASSOCIATED;
if ( clear & NET80211_ASSOCIATED )
clear |= NET80211_CRYPTO_SYNCED;
dev->state = ( dev->state & ~clear ) | set;
dev->state = ( dev->state & ~statmsk ) | ( status & statmsk );
if ( clear & NET80211_ASSOCIATED )
netdev_link_down ( dev->netdev );
if ( ( clear | set ) & NET80211_ASSOCIATED )
dev->op->config ( dev, NET80211_CFG_ASSOC );
if ( status != 0 ) {
if ( status & NET80211_IS_REASON )
dev->assoc_rc = -E80211_REASON ( status );
else
dev->assoc_rc = -E80211_STATUS ( status );
netdev_link_err ( dev->netdev, dev->assoc_rc );
}
}
/**
* Add channels to 802.11 device
*
* @v dev 802.11 device
* @v start First channel number to add
* @v len Number of channels to add
* @v txpower TX power (dBm) to allow on added channels
*
* To replace the current list of channels instead of adding to it,
* set the nr_channels field of the 802.11 device to 0 before calling
* this function.
*/
static void net80211_add_channels ( struct net80211_device *dev, int start,
int len, int txpower )
{
int i, chan = start;
for ( i = dev->nr_channels; len-- && i < NET80211_MAX_CHANNELS; i++ ) {
dev->channels[i].channel_nr = chan;
dev->channels[i].maxpower = txpower;
dev->channels[i].hw_value = 0;
if ( chan >= 1 && chan <= 14 ) {
dev->channels[i].band = NET80211_BAND_2GHZ;
if ( chan == 14 )
dev->channels[i].center_freq = 2484;
else
dev->channels[i].center_freq = 2407 + 5 * chan;
chan++;
} else {
dev->channels[i].band = NET80211_BAND_5GHZ;
dev->channels[i].center_freq = 5000 + 5 * chan;
chan += 4;
}
}
dev->nr_channels = i;
}
/**
* Filter 802.11 device channels for hardware capabilities
*
* @v dev 802.11 device
*
* Hardware may support fewer channels than regulatory restrictions
* allow; this function filters out channels in dev->channels that are
* not supported by the hardware list in dev->hwinfo. It also copies
* over the net80211_channel::hw_value and limits maximum TX power
* appropriately.
*
* Channels are matched based on center frequency, ignoring band and
* channel number.
*
* If the driver specifies no supported channels, the effect will be
* as though all were supported.
*/
static void net80211_filter_hw_channels ( struct net80211_device *dev )
{
int delta = 0, i = 0;
int old_freq = dev->channels[dev->channel].center_freq;
struct net80211_channel *chan, *hwchan;
if ( ! dev->hw->nr_channels )
return;
dev->channel = 0;
for ( chan = dev->channels; chan < dev->channels + dev->nr_channels;
chan++, i++ ) {
int ok = 0;
for ( hwchan = dev->hw->channels;
hwchan < dev->hw->channels + dev->hw->nr_channels;
hwchan++ ) {
if ( hwchan->center_freq == chan->center_freq ) {
ok = 1;
break;
}
}
if ( ! ok )
delta++;
else {
chan->hw_value = hwchan->hw_value;
if ( hwchan->maxpower != 0 &&
chan->maxpower > hwchan->maxpower )
chan->maxpower = hwchan->maxpower;
if ( old_freq == chan->center_freq )
dev->channel = i - delta;
if ( delta )
chan[-delta] = *chan;
}
}
dev->nr_channels -= delta;
if ( dev->channels[dev->channel].center_freq != old_freq )
dev->op->config ( dev, NET80211_CFG_CHANNEL );
}
/**
* Update 802.11 device state to reflect received capabilities field
*
* @v dev 802.11 device
* @v capab Capabilities field in beacon, probe, or association frame
* @ret rc Return status code
*/
static int net80211_process_capab ( struct net80211_device *dev,
u16 capab )
{
u16 old_phy = dev->phy_flags;
if ( ( capab & ( IEEE80211_CAPAB_MANAGED | IEEE80211_CAPAB_ADHOC ) ) !=
IEEE80211_CAPAB_MANAGED ) {
DBGC ( dev, "802.11 %p cannot handle IBSS network\n", dev );
return -ENOSYS;
}
if ( capab & IEEE80211_CAPAB_SPECTRUM_MGMT ) {
DBGC ( dev, "802.11 %p cannot handle spectrum managed "
"network\n", dev );
return -ENOSYS;
}
dev->phy_flags &= ~( NET80211_PHY_USE_SHORT_PREAMBLE |
NET80211_PHY_USE_SHORT_SLOT );
if ( capab & IEEE80211_CAPAB_SHORT_PMBL )
dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
if ( capab & IEEE80211_CAPAB_SHORT_SLOT )
dev->phy_flags |= NET80211_PHY_USE_SHORT_SLOT;
if ( old_phy != dev->phy_flags )
dev->op->config ( dev, NET80211_CFG_PHY_PARAMS );
return 0;
}
/**
* Update 802.11 device state to reflect received information elements
*
* @v dev 802.11 device
* @v ie Pointer to first information element
* @v ie_end Pointer to tail of packet I/O buffer
* @ret rc Return status code
*/
static int net80211_process_ie ( struct net80211_device *dev,
union ieee80211_ie *ie, void *ie_end )
{
u16 old_rate = dev->rates[dev->rate];
u16 old_phy = dev->phy_flags;
int have_rates = 0, i;
int ds_channel = 0;
int changed = 0;
int band = dev->channels[dev->channel].band;
if ( ( void * ) ie >= ie_end )
return 0;
for ( ; ie; ie = ieee80211_next_ie ( ie, ie_end ) ) {
switch ( ie->id ) {
case IEEE80211_IE_SSID:
if ( ie->len <= 32 ) {
memcpy ( dev->essid, ie->ssid, ie->len );
dev->essid[ie->len] = 0;
}
break;
case IEEE80211_IE_RATES:
case IEEE80211_IE_EXT_RATES:
if ( ! have_rates ) {
dev->nr_rates = 0;
dev->basic_rates = 0;
have_rates = 1;
}
for ( i = 0; i < ie->len &&
dev->nr_rates < NET80211_MAX_RATES; i++ ) {
u8 rid = ie->rates[i];
u16 rate = ( rid & 0x7f ) * 5;
if ( rid & 0x80 )
dev->basic_rates |=
( 1 << dev->nr_rates );
dev->rates[dev->nr_rates++] = rate;
}
break;
case IEEE80211_IE_DS_PARAM:
if ( dev->channel < dev->nr_channels && ds_channel ==
dev->channels[dev->channel].channel_nr )
break;
ds_channel = ie->ds_param.current_channel;
net80211_change_channel ( dev, ds_channel );
break;
case IEEE80211_IE_COUNTRY:
dev->nr_channels = 0;
DBGC ( dev, "802.11 %p setting country regulations "
"for %c%c\n", dev, ie->country.name[0],
ie->country.name[1] );
for ( i = 0; i < ( ie->len - 3 ) / 3; i++ ) {
union ieee80211_ie_country_triplet *t =
&ie->country.triplet[i];
if ( t->first > 200 ) {
DBGC ( dev, "802.11 %p ignoring regulatory "
"extension information\n", dev );
} else {
net80211_add_channels ( dev,
t->band.first_channel,
t->band.nr_channels,
t->band.max_txpower );
}
}
net80211_filter_hw_channels ( dev );
break;
case IEEE80211_IE_ERP_INFO:
dev->phy_flags &= ~( NET80211_PHY_USE_PROTECTION |
NET80211_PHY_USE_SHORT_PREAMBLE );
if ( ie->erp_info & IEEE80211_ERP_USE_PROTECTION )
dev->phy_flags |= NET80211_PHY_USE_PROTECTION;
if ( ! ( ie->erp_info & IEEE80211_ERP_BARKER_LONG ) )
dev->phy_flags |= NET80211_PHY_USE_SHORT_PREAMBLE;
break;
case IEEE80211_IE_RSN:
/* XXX need to implement WPA stuff */
break;
}
}
if ( have_rates ) {
/* Allow only those rates that are also supported by
the hardware. */
int delta = 0, j;
dev->rate = 0;
for ( i = 0; i < dev->nr_rates; i++ ) {
int ok = 0;
for ( j = 0; j < dev->hw->nr_rates[band]; j++ ) {
if ( dev->hw->rates[band][j] == dev->rates[i] ){
ok = 1;
break;
}
}
if ( ! ok )
delta++;
else {
dev->rates[i - delta] = dev->rates[i];
if ( old_rate == dev->rates[i] )
dev->rate = i - delta;
}
}
dev->nr_rates -= delta;
/* Sort available rates - sorted subclumps tend to already
exist, so insertion sort works well. */
for ( i = 1; i < dev->nr_rates; i++ ) {
u16 rate = dev->rates[i];
for ( j = i - 1; j >= 0 && dev->rates[j] >= rate; j-- )
dev->rates[j + 1] = dev->rates[j];
dev->rates[j + 1] = rate;
}
net80211_set_rtscts_rate ( dev );
if ( dev->rates[dev->rate] != old_rate )
changed |= NET80211_CFG_RATE;
}
if ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE )
dev->phy_flags &= ~NET80211_PHY_USE_SHORT_PREAMBLE;
if ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT )
dev->phy_flags &= ~NET80211_PHY_USE_SHORT_SLOT;
if ( old_phy != dev->phy_flags )
changed |= NET80211_CFG_PHY_PARAMS;
if ( changed )
dev->op->config ( dev, changed );
return 0;
}
/**
* Create information elements for outgoing probe or association packet
*
* @v dev 802.11 device
* @v ie Pointer to start of information element area
* @ret next_ie Pointer to first byte after added information elements
*/
static union ieee80211_ie *
net80211_marshal_request_info ( struct net80211_device *dev,
union ieee80211_ie *ie )
{
int i;
ie->id = IEEE80211_IE_SSID;
ie->len = strlen ( dev->essid );
memcpy ( ie->ssid, dev->essid, ie->len );
ie = ieee80211_next_ie ( ie, NULL );
ie->id = IEEE80211_IE_RATES;
ie->len = dev->nr_rates;
for ( i = 0; i < ie->len; i++ ) {
ie->rates[i] = dev->rates[i] / 5;
if ( dev->basic_rates & ( 1 << i ) )
ie->rates[i] |= 0x80;
}
if ( ie->len > 8 ) {
/* 802.11 requires we use an Extended Basic Rates IE
for the rates beyond the eighth. */
int rates = ie->len;
memmove ( ( void * ) ie + 2 + 8 + 2, ( void * ) ie + 2 + 8,
rates - 8 );
ie->len = 8;
ie = ieee80211_next_ie ( ie, NULL );
ie->id = IEEE80211_IE_EXT_RATES;
ie->len = rates - 8;
}
ie = ieee80211_next_ie ( ie, NULL );
return ie;
}
/** Seconds to wait after finding a network, to possibly find better APs for it
*
* This is used when a specific SSID to scan for is specified.
*/
#define NET80211_PROBE_GATHER 1
/** Seconds to wait after finding a network, to possibly find other networks
*
* This is used when an empty SSID is specified, to scan for all
* networks.
*/
#define NET80211_PROBE_GATHER_ALL 2
/** Seconds to allow a probe to take if no network has been found */
#define NET80211_PROBE_TIMEOUT 6
/**
* Begin probe of 802.11 networks
*
* @v dev 802.11 device
* @v essid SSID to probe for, or "" to accept any (may not be NULL)
* @v active Whether to use active scanning
* @ret ctx Probe context
*
* Active scanning may only be used on channels 1-11 in the 2.4GHz
* band, due to gPXE's lack of a complete regulatory database. If
* active scanning is used, probe packets will be sent on each
* channel; this can allow association with hidden-SSID networks if
* the SSID is properly specified.
*
* A @c NULL return indicates an out-of-memory condition.
*
* The returned context must be periodically passed to
* net80211_probe_step() until that function returns zero.
*/
struct net80211_probe_ctx * net80211_probe_start ( struct net80211_device *dev,
const char *essid,
int active )
{
struct net80211_probe_ctx *ctx = zalloc ( sizeof ( *ctx ) );
if ( ! ctx )
return NULL;
assert ( dev->netdev->state & NETDEV_OPEN );
ctx->dev = dev;
ctx->old_keep_mgmt = net80211_keep_mgmt ( dev, 1 );
ctx->essid = essid;
if ( dev->essid != ctx->essid )
strcpy ( dev->essid, ctx->essid );
if ( active ) {
struct ieee80211_probe_req *probe_req;
union ieee80211_ie *ie;
ctx->probe = alloc_iob ( 128 );
iob_reserve ( ctx->probe, IEEE80211_TYP_FRAME_HEADER_LEN );
probe_req = ctx->probe->data;
ie = net80211_marshal_request_info ( dev,
probe_req->info_element );
ie->id = IEEE80211_IE_REQUEST;
ie->len = 3;
ie->request[0] = IEEE80211_IE_COUNTRY;
ie->request[1] = IEEE80211_IE_ERP_INFO;
ie->request[2] = IEEE80211_IE_RSN;
ie = ieee80211_next_ie ( ie, NULL );
iob_put ( ctx->probe, ( void * ) ie - ctx->probe->data );
}
ctx->ticks_start = currticks();
ctx->ticks_beacon = 0;
ctx->ticks_channel = currticks();
ctx->hop_time = ticks_per_sec() / ( active ? 2 : 6 );
/*
* Channels on 2.4GHz overlap, and the most commonly used
* are 1, 6, and 11. We'll get a result faster if we check
* every 5 channels, but in order to hit all of them the
* number of channels must be relatively prime to 5. If it's
* not, tweak the hop.
*/
ctx->hop_step = 5;
while ( dev->nr_channels % ctx->hop_step == 0 && ctx->hop_step > 1 )
ctx->hop_step--;
ctx->beacons = malloc ( sizeof ( *ctx->beacons ) );
INIT_LIST_HEAD ( ctx->beacons );
dev->channel = 0;
dev->op->config ( dev, NET80211_CFG_CHANNEL );
return ctx;
}
/**
* Continue probe of 802.11 networks
*
* @v ctx Probe context returned by net80211_probe_start()
* @ret rc Probe status
*
* The return code will be 0 if the probe is still going on (and this
* function should be called again), a positive number if the probe
* completed successfully, or a negative error code if the probe
* failed for that reason.
*
* Whether the probe succeeded or failed, you must call
* net80211_probe_finish_all() or net80211_probe_finish_best()
* (depending on whether you want information on all networks or just
* the best-signal one) in order to release the probe context. A
* failed probe may still have acquired some valid data.
*/
int net80211_probe_step ( struct net80211_probe_ctx *ctx )
{
struct net80211_device *dev = ctx->dev;
u32 start_timeout = NET80211_PROBE_TIMEOUT * ticks_per_sec();
u32 gather_timeout = ticks_per_sec();
u32 now = currticks();
struct io_buffer *iob;
int signal;
int rc;
char ssid[IEEE80211_MAX_SSID_LEN + 1];
gather_timeout *= ( ctx->essid[0] ? NET80211_PROBE_GATHER :
NET80211_PROBE_GATHER_ALL );
/* Time out if necessary */
if ( now >= ctx->ticks_start + start_timeout )
return list_empty ( ctx->beacons ) ? -ETIMEDOUT : +1;
if ( ctx->ticks_beacon > 0 && now >= ctx->ticks_start + gather_timeout )
return +1;
/* Change channels if necessary */
if ( now >= ctx->ticks_channel + ctx->hop_time ) {
dev->channel = ( dev->channel + ctx->hop_step )
% dev->nr_channels;
dev->op->config ( dev, NET80211_CFG_CHANNEL );
udelay ( dev->hw->channel_change_time );
ctx->ticks_channel = now;
if ( ctx->probe ) {
struct io_buffer *siob = ctx->probe; /* to send */
/* make a copy for future use */
iob = alloc_iob ( siob->tail - siob->head );
iob_reserve ( iob, iob_headroom ( siob ) );
memcpy ( iob_put ( iob, iob_len ( siob ) ),
siob->data, iob_len ( siob ) );
ctx->probe = iob;
rc = net80211_tx_mgmt ( dev, IEEE80211_STYPE_PROBE_REQ,
net80211_ll_broadcast,
iob_disown ( siob ) );
if ( rc ) {
DBGC ( dev, "802.11 %p send probe failed: "
"%s\n", dev, strerror ( rc ) );
return rc;
}
}
}
/* Check for new management packets */
while ( ( iob = net80211_mgmt_dequeue ( dev, &signal ) ) != NULL ) {
struct ieee80211_frame *hdr;
struct ieee80211_beacon *beacon;
union ieee80211_ie *ie;
struct net80211_wlan *wlan;
u16 type;
hdr = iob->data;
type = hdr->fc & IEEE80211_FC_SUBTYPE;
beacon = ( struct ieee80211_beacon * ) hdr->data;
if ( type != IEEE80211_STYPE_BEACON &&
type != IEEE80211_STYPE_PROBE_RESP ) {
DBGC2 ( dev, "802.11 %p probe: non-beacon\n", dev );
goto drop;
}
if ( ( void * ) beacon->info_element >= iob->tail ) {
DBGC ( dev, "802.11 %p probe: beacon with no IEs\n",
dev );
goto drop;
}
ie = beacon->info_element;
while ( ie && ie->id != IEEE80211_IE_SSID )
ie = ieee80211_next_ie ( ie, iob->tail );
if ( ! ie ) {
DBGC ( dev, "802.11 %p probe: beacon with no SSID\n",
dev );
goto drop;
}
memcpy ( ssid, ie->ssid, ie->len );
ssid[ie->len] = 0;
if ( ctx->essid[0] && strcmp ( ctx->essid, ssid ) != 0 ) {
DBGC2 ( dev, "802.11 %p probe: beacon with wrong SSID "
"(%s)\n", dev, ssid );
goto drop;
}
/* See if we've got an entry for this network */
list_for_each_entry ( wlan, ctx->beacons, list ) {
if ( strcmp ( wlan->essid, ssid ) != 0 )
continue;
if ( signal < wlan->signal ) {
DBGC2 ( dev, "802.11 %p probe: beacon for %s "
"(%s) with weaker signal %d\n", dev,
ssid, eth_ntoa ( hdr->addr3 ), signal );
goto drop;
}
goto fill;
}
/* No entry yet - make one */
wlan = zalloc ( sizeof ( *wlan ) );
strcpy ( wlan->essid, ssid );
list_add_tail ( &wlan->list, ctx->beacons );
/* Whether we're using an old entry or a new one, fill
it with new data. */
fill:
memcpy ( wlan->bssid, hdr->addr3, ETH_ALEN );
wlan->signal = signal;
wlan->channel = dev->channels[dev->channel].channel_nr;
/* Copy this I/O buffer into a new wlan->beacon; the
* iob we've got probably came from the device driver
* and may have the full 2.4k allocation, which we
* don't want to keep around wasting memory.
*/
free_iob ( wlan->beacon );
wlan->beacon = alloc_iob ( iob_len ( iob ) );
memcpy ( iob_put ( wlan->beacon, iob_len ( iob ) ),
iob->data, iob_len ( iob ) );
/* XXX actually check capab and RSN ie to
figure this out */
wlan->handshaking = NET80211_SECPROT_NONE;
wlan->crypto = NET80211_CRYPT_NONE;
ctx->ticks_beacon = now;
DBGC2 ( dev, "802.11 %p probe: good beacon for %s (%s)\n",
dev, wlan->essid, eth_ntoa ( wlan->bssid ) );
drop:
free_iob ( iob );
}
return 0;
}
/**
* Finish probe of 802.11 networks, returning best-signal network found
*
* @v ctx Probe context
* @ret wlan Best-signal network found, or @c NULL if none were found
*
* If net80211_probe_start() was called with a particular SSID
* parameter as filter, only a network with that SSID (matching
* case-sensitively) can be returned from this function.
*/
struct net80211_wlan *
net80211_probe_finish_best ( struct net80211_probe_ctx *ctx )
{
struct net80211_wlan *best = NULL, *wlan;
if ( ! ctx )
return NULL;
list_for_each_entry ( wlan, ctx->beacons, list ) {
if ( ! best || best->signal < wlan->signal )
best = wlan;
}
if ( best )
list_del ( &best->list );
else
DBGC ( ctx->dev, "802.11 %p probe: found nothing for '%s'\n",
ctx->dev, ctx->essid );
net80211_free_wlanlist ( ctx->beacons );
net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
if ( ctx->probe )
free_iob ( ctx->probe );
free ( ctx );
return best;
}
/**
* Finish probe of 802.11 networks, returning all networks found
*
* @v ctx Probe context
* @ret list List of net80211_wlan detailing networks found
*
* If net80211_probe_start() was called with a particular SSID
* parameter as filter, this will always return either an empty or a
* one-element list.
*/
struct list_head *net80211_probe_finish_all ( struct net80211_probe_ctx *ctx )
{
struct list_head *beacons = ctx->beacons;
if ( ! ctx )
return NULL;
net80211_keep_mgmt ( ctx->dev, ctx->old_keep_mgmt );
if ( ctx->probe )
free_iob ( ctx->probe );
free ( ctx );
return beacons;
}
/**
* Free WLAN structure
*
* @v wlan WLAN structure to free
*/
void net80211_free_wlan ( struct net80211_wlan *wlan )
{
if ( wlan ) {
free_iob ( wlan->beacon );
free ( wlan );
}
}
/**
* Free list of WLAN structures
*
* @v list List of WLAN structures to free
*/
void net80211_free_wlanlist ( struct list_head *list )
{
struct net80211_wlan *wlan, *tmp;
if ( ! list )
return;
list_for_each_entry_safe ( wlan, tmp, list, list ) {
list_del ( &wlan->list );
net80211_free_wlan ( wlan );
}
free ( list );
}
/** Number of ticks to wait for replies to association management frames */
#define ASSOC_TIMEOUT TICKS_PER_SEC
/** Number of times to try sending a particular association management frame */
#define ASSOC_RETRIES 2
/**
* Step 802.11 association process
*
* @v proc Association process
*/
static void net80211_step_associate ( struct process *proc )
{
struct net80211_device *dev =
container_of ( proc, struct net80211_device, proc_assoc );
int rc = 0;
int status = dev->state & NET80211_STATUS_MASK;
/*
* We use a sort of state machine implemented using bits in
* the dev->state variable. At each call, we take the
* logically first step that has not yet succeeded; either it
* has not been tried yet, it's being retried, or it failed.
* If it failed, we return an error indication; otherwise we
* perform the step. If it succeeds, RX handling code will set
* the appropriate status bit for us.
*
* Probe works a bit differently, since we have to step it
* on every call instead of waiting for a packet to arrive
* that will set the completion bit for us.
*/
/* If we're waiting for a reply, check for timeout condition */
if ( dev->state & NET80211_WAITING ) {
/* Sanity check */
if ( ! dev->associating )
return;
if ( currticks() - dev->ctx.assoc->last_packet > ASSOC_TIMEOUT ) {
/* Timed out - fail if too many retries, or retry */
dev->ctx.assoc->times_tried++;
if ( ++dev->ctx.assoc->times_tried > ASSOC_RETRIES ) {
rc = -ETIMEDOUT;
goto fail;
}
} else {
/* Didn't time out - let it keep going */
return;
}
} else {
if ( dev->state & NET80211_PROBED )
dev->ctx.assoc->times_tried = 0;
}
if ( ! ( dev->state & NET80211_PROBED ) ) {
/* state: probe */
if ( ! dev->ctx.probe ) {
/* start probe */
int active = fetch_intz_setting ( NULL,
&net80211_active_setting );
int band = dev->hw->bands;
if ( active )
band &= ~NET80211_BAND_BIT_5GHZ;
rc = net80211_prepare_probe ( dev, band, active );
if ( rc )
goto fail;
dev->ctx.probe = net80211_probe_start ( dev, dev->essid,
active );
if ( ! dev->ctx.probe ) {
dev->assoc_rc = -ENOMEM;
goto fail;
}
}
rc = net80211_probe_step ( dev->ctx.probe );
if ( ! rc ) {
return; /* still going */
}
dev->associating = net80211_probe_finish_best ( dev->ctx.probe );
dev->ctx.probe = NULL;
if ( ! dev->associating ) {
if ( rc > 0 ) /* "successful" probe found nothing */
rc = -ETIMEDOUT;
goto fail;
}
/* If we probed using a broadcast SSID, record that
fact for the settings applicator before we clobber
it with the specific SSID we've chosen. */
if ( ! dev->essid[0] )
dev->state |= NET80211_AUTO_SSID;
DBGC ( dev, "802.11 %p found network %s (%s)\n", dev,
dev->associating->essid,
eth_ntoa ( dev->associating->bssid ) );
dev->ctx.assoc = zalloc ( sizeof ( *dev->ctx.assoc ) );
if ( ! dev->ctx.assoc ) {
rc = -ENOMEM;
goto fail;
}
dev->state |= NET80211_PROBED;
dev->ctx.assoc->method = IEEE80211_AUTH_OPEN_SYSTEM;
return;
}
/* Record time of sending the packet we're about to send, for timeout */
dev->ctx.assoc->last_packet = currticks();
if ( ! ( dev->state & NET80211_AUTHENTICATED ) ) {
/* state: prepare and authenticate */
if ( status != IEEE80211_STATUS_SUCCESS ) {
/* we tried authenticating already, but failed */
int method = dev->ctx.assoc->method;
if ( method == IEEE80211_AUTH_OPEN_SYSTEM &&
( status == IEEE80211_STATUS_AUTH_CHALL_INVALID ||
status == IEEE80211_STATUS_AUTH_ALGO_UNSUPP ) ) {
/* Maybe this network uses Shared Key? */
dev->ctx.assoc->method =
IEEE80211_AUTH_SHARED_KEY;
} else {
goto fail;
}
}
DBGC ( dev, "802.11 %p authenticating with method %d\n", dev,
dev->ctx.assoc->method );
rc = net80211_prepare_assoc ( dev, dev->associating );
if ( rc )
goto fail;
rc = net80211_send_auth ( dev, dev->associating,
dev->ctx.assoc->method );
if ( rc )
goto fail;
return;
}
if ( ! ( dev->state & NET80211_ASSOCIATED ) ) {
/* state: associate */
if ( status != IEEE80211_STATUS_SUCCESS )
goto fail;
DBGC ( dev, "802.11 %p associating\n", dev );
rc = net80211_send_assoc ( dev, dev->associating );
if ( rc )
goto fail;
return;
}
if ( ! ( dev->state & NET80211_CRYPTO_SYNCED ) ) {
/* state: crypto sync */
DBGC ( dev, "802.11 %p security handshaking\n", dev );
dev->state |= NET80211_CRYPTO_SYNCED;
/* XXX need to actually do something here once we
support WPA */
return;
}
/* state: done! */
netdev_link_up ( dev->netdev );
dev->assoc_rc = 0;
dev->state &= ~NET80211_WORKING;
free ( dev->ctx.assoc );
dev->ctx.assoc = NULL;
net80211_free_wlan ( dev->associating );
dev->associating = NULL;
dev->rctl = rc80211_init ( dev );
process_del ( proc );
DBGC ( dev, "802.11 %p associated with %s (%s)\n", dev,
dev->essid, eth_ntoa ( dev->bssid ) );
return;
fail:
dev->state &= ~( NET80211_WORKING | NET80211_WAITING );
if ( rc )
dev->assoc_rc = rc;
netdev_link_err ( dev->netdev, dev->assoc_rc );
/* We never reach here from the middle of a probe, so we don't
need to worry about freeing dev->ctx.probe. */
if ( dev->state & NET80211_PROBED ) {
free ( dev->ctx.assoc );
dev->ctx.assoc = NULL;
}
net80211_free_wlan ( dev->associating );
dev->associating = NULL;
process_del ( proc );
DBGC ( dev, "802.11 %p association failed (state=%04x): "
"%s\n", dev, dev->state, strerror ( dev->assoc_rc ) );
/* Try it again: */
net80211_autoassociate ( dev );
}
/**
* Check for 802.11 SSID updates
*
* This acts as a settings applicator; if the user changes netX/ssid,
* and netX is currently open, the association task will be invoked
* again.
*/
static int net80211_check_ssid_update ( void )
{
struct net80211_device *dev;
char ssid[IEEE80211_MAX_SSID_LEN + 1];
list_for_each_entry ( dev, &net80211_devices, list ) {
if ( ! ( dev->netdev->state & NETDEV_OPEN ) )
continue;
fetch_string_setting ( netdev_settings ( dev->netdev ),
&net80211_ssid_setting, ssid,
IEEE80211_MAX_SSID_LEN + 1 );
if ( strcmp ( ssid, dev->essid ) != 0 &&
! ( ! ssid[0] && ( dev->state & NET80211_AUTO_SSID ) ) ) {
DBGC ( dev, "802.11 %p updating association: "
"%s -> %s\n", dev, dev->essid, ssid );
net80211_autoassociate ( dev );
}
}
return 0;
}
/**
* Start 802.11 association process
*
* @v dev 802.11 device
*
* If the association process is running, it will be restarted.
*/
void net80211_autoassociate ( struct net80211_device *dev )
{
if ( ! ( dev->state & NET80211_WORKING ) ) {
DBGC2 ( dev, "802.11 %p spawning association process\n", dev );
process_add ( &dev->proc_assoc );
}
/* Clean up everything an earlier association process might
have been in the middle of using */
if ( dev->associating )
net80211_free_wlan ( dev->associating );
if ( ! ( dev->state & NET80211_PROBED ) )
net80211_free_wlan (
net80211_probe_finish_best ( dev->ctx.probe ) );
else
free ( dev->ctx.assoc );
/* Reset to a clean state */
fetch_string_setting ( netdev_settings ( dev->netdev ),
&net80211_ssid_setting, dev->essid,
IEEE80211_MAX_SSID_LEN + 1 );
dev->ctx.probe = NULL;
dev->associating = NULL;
net80211_set_state ( dev, NET80211_PROBED, NET80211_WORKING, 0 );
}
/**
* Pick TX rate for RTS/CTS packets based on data rate
*
* @v dev 802.11 device
*
* The RTS/CTS rate is the fastest TX rate marked as "basic" that is
* not faster than the data rate.
*/
static void net80211_set_rtscts_rate ( struct net80211_device *dev )
{
u16 datarate = dev->rates[dev->rate];
u16 rtsrate = 0;
int rts_idx = -1;
int i;
for ( i = 0; i < dev->nr_rates; i++ ) {
u16 rate = dev->rates[i];
if ( ! ( dev->basic_rates & ( 1 << i ) ) || rate > datarate )
continue;
if ( rate > rtsrate ) {
rtsrate = rate;
rts_idx = i;
}
}
/* If this is in initialization, we might not have any basic
rates; just use the first data rate in that case. */
if ( rts_idx < 0 )
rts_idx = 0;
dev->rtscts_rate = rts_idx;
}
/**
* Set data transmission rate for 802.11 device
*
* @v dev 802.11 device
* @v rate Rate to set, as index into @c dev->rates array
*/
void net80211_set_rate_idx ( struct net80211_device *dev, int rate )
{
assert ( dev->netdev->state & NETDEV_OPEN );
if ( rate >= 0 && rate < dev->nr_rates && rate != dev->rate ) {
DBGC2 ( dev, "802.11 %p changing rate from %d->%d Mbps\n",
dev, dev->rates[dev->rate] / 10,
dev->rates[rate] / 10 );
dev->rate = rate;
net80211_set_rtscts_rate ( dev );
dev->op->config ( dev, NET80211_CFG_RATE );
}
}
/**
* Configure 802.11 device to transmit on a certain channel
*
* @v dev 802.11 device
* @v channel Channel number (1-11 for 2.4GHz) to transmit on
*/
int net80211_change_channel ( struct net80211_device *dev, int channel )
{
int i, oldchan = dev->channel;
assert ( dev->netdev->state & NETDEV_OPEN );
for ( i = 0; i < dev->nr_channels; i++ ) {
if ( dev->channels[i].channel_nr == channel ) {
dev->channel = i;
break;
}
}
if ( i == dev->nr_channels )
return -ENOENT;
if ( i != oldchan )
return dev->op->config ( dev, NET80211_CFG_CHANNEL );
return 0;
}
/**
* Prepare 802.11 device channel and rate set for scanning
*
* @v dev 802.11 device
* @v band RF band(s) on which to prepare for scanning
* @v active Whether the scanning will be active
* @ret rc Return status code
*/
int net80211_prepare_probe ( struct net80211_device *dev, int band,
int active )
{
assert ( dev->netdev->state & NETDEV_OPEN );
if ( active && ( band & NET80211_BAND_BIT_5GHZ ) ) {
DBGC ( dev, "802.11 %p cannot perform active scanning on "
"5GHz band\n", dev );
return -EINVAL_ACTIVE_SCAN;
}
if ( band == 0 ) {
/* This can happen for a 5GHz-only card with 5GHz
scanning masked out by an active request. */
DBGC ( dev, "802.11 %p asked to prepare for scanning nothing\n",
dev );
return -EINVAL_ACTIVE_SCAN;
}
dev->nr_channels = 0;
if ( active )
net80211_add_channels ( dev, 1, 11, NET80211_REG_TXPOWER );
else {
if ( band & NET80211_BAND_BIT_2GHZ )
net80211_add_channels ( dev, 1, 14,
NET80211_REG_TXPOWER );
if ( band & NET80211_BAND_BIT_5GHZ )
net80211_add_channels ( dev, 36, 8,
NET80211_REG_TXPOWER );
}
net80211_filter_hw_channels ( dev );
/* Use channel 1 for now */
dev->channel = 0;
dev->op->config ( dev, NET80211_CFG_CHANNEL );
/* Always do active probes at lowest (presumably first) speed */
dev->rate = 0;
dev->nr_rates = 1;
dev->rates[0] = dev->hw->rates[dev->channels[0].band][0];
dev->op->config ( dev, NET80211_CFG_RATE );
return 0;
}
/**
* Prepare 802.11 device channel and rate set for communication
*
* @v dev 802.11 device
* @v wlan WLAN to prepare for communication with
* @ret rc Return status code
*/
int net80211_prepare_assoc ( struct net80211_device *dev,
struct net80211_wlan *wlan )
{
struct ieee80211_frame *hdr = wlan->beacon->data;
struct ieee80211_beacon *beacon =
( struct ieee80211_beacon * ) hdr->data;
int rc;
assert ( dev->netdev->state & NETDEV_OPEN );
net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
memcpy ( dev->bssid, wlan->bssid, ETH_ALEN );
strcpy ( dev->essid, wlan->essid );
dev->last_beacon_timestamp = beacon->timestamp;
dev->tx_beacon_interval = 1024 * beacon->beacon_interval;
/* XXX do crypto setup here */
/* Barring an IE that tells us the channel outright, assume
the channel we heard this AP best on is the channel it's
communicating on. */
net80211_change_channel ( dev, wlan->channel );
rc = net80211_process_capab ( dev, beacon->capability );
if ( rc )
return rc;
rc = net80211_process_ie ( dev, beacon->info_element,
wlan->beacon->tail );
if ( rc )
return rc;
/* Associate at the lowest rate so we know it'll get through */
dev->rate = 0;
dev->op->config ( dev, NET80211_CFG_RATE );
return 0;
}
/**
* Send 802.11 initial authentication frame
*
* @v dev 802.11 device
* @v wlan WLAN to authenticate with
* @v method Authentication method
* @ret rc Return status code
*
* @a method may be 0 for Open System authentication or 1 for Shared
* Key authentication. Open System provides no security in association
* whatsoever, relying on encryption for confidentiality, but Shared
* Key actively introduces security problems and is very rarely used.
*/
int net80211_send_auth ( struct net80211_device *dev,
struct net80211_wlan *wlan, int method )
{
struct io_buffer *iob = alloc_iob ( 64 );
struct ieee80211_auth *auth;
net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
auth = iob_put ( iob, sizeof ( *auth ) );
auth->algorithm = method;
auth->tx_seq = 1;
auth->status = 0;
return net80211_tx_mgmt ( dev, IEEE80211_STYPE_AUTH, wlan->bssid, iob );
}
/**
* Handle receipt of 802.11 authentication frame
*
* @v dev 802.11 device
* @v iob I/O buffer
*
* If the authentication method being used is Shared Key, and the
* frame that was received included challenge text, the frame is
* encrypted using the cryptographic algorithm currently in effect and
* sent back to the AP to complete the authentication.
*/
static void net80211_handle_auth ( struct net80211_device *dev,
struct io_buffer *iob )
{
struct ieee80211_frame *hdr = iob->data;
struct ieee80211_auth *auth =
( struct ieee80211_auth * ) hdr->data;
if ( auth->tx_seq & 1 ) {
DBGC ( dev, "802.11 %p authentication received improperly "
"directed frame (seq. %d)\n", dev, auth->tx_seq );
net80211_set_state ( dev, NET80211_WAITING, 0,
IEEE80211_STATUS_FAILURE );
return;
}
if ( auth->status != IEEE80211_STATUS_SUCCESS ) {
DBGC ( dev, "802.11 %p authentication failed: status %d\n",
dev, auth->status );
net80211_set_state ( dev, NET80211_WAITING, 0,
auth->status );
return;
}
if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY && ! dev->crypto ) {
DBGC ( dev, "802.11 %p can't perform shared-key authentication "
"without a cryptosystem\n", dev );
net80211_set_state ( dev, NET80211_WAITING, 0,
IEEE80211_STATUS_FAILURE );
return;
}
if ( auth->algorithm == IEEE80211_AUTH_SHARED_KEY &&
auth->tx_seq == 2 ) {
/* Since the iob we got is going to be freed as soon
as we return, we can do some in-place
modification. */
auth->tx_seq = 3;
auth->status = 0;
memcpy ( hdr->addr2, hdr->addr1, ETH_ALEN );
memcpy ( hdr->addr1, hdr->addr3, ETH_ALEN );
netdev_tx ( dev->netdev,
dev->crypto->encrypt ( dev->crypto, iob ) );
return;
}
net80211_set_state ( dev, NET80211_WAITING, NET80211_AUTHENTICATED,
IEEE80211_STATUS_SUCCESS );
return;
}
/**
* Send 802.11 association frame
*
* @v dev 802.11 device
* @v wlan WLAN to associate with
* @ret rc Return status code
*/
int net80211_send_assoc ( struct net80211_device *dev,
struct net80211_wlan *wlan )
{
struct io_buffer *iob = alloc_iob ( 128 );
struct ieee80211_assoc_req *assoc;
union ieee80211_ie *ie;
net80211_set_state ( dev, 0, NET80211_WAITING, 0 );
iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
assoc = iob->data;
assoc->capability = IEEE80211_CAPAB_MANAGED;
if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_PREAMBLE ) )
assoc->capability |= IEEE80211_CAPAB_SHORT_PMBL;
if ( ! ( dev->hw->flags & NET80211_HW_NO_SHORT_SLOT ) )
assoc->capability |= IEEE80211_CAPAB_SHORT_SLOT;
if ( wlan->crypto )
assoc->capability |= IEEE80211_CAPAB_PRIVACY;
assoc->listen_interval = 1;
ie = net80211_marshal_request_info ( dev, assoc->info_element );
DBGP ( "802.11 %p about to send association request:\n", dev );
DBGP_HD ( iob->data, ( void * ) ie - iob->data );
/* XXX add RSN ie for WPA support */
iob_put ( iob, ( void * ) ie - iob->data );
return net80211_tx_mgmt ( dev, IEEE80211_STYPE_ASSOC_REQ,
wlan->bssid, iob );
}
/**
* Handle receipt of 802.11 association reply frame
*
* @v dev 802.11 device
* @v iob I/O buffer
*/
static void net80211_handle_assoc_reply ( struct net80211_device *dev,
struct io_buffer *iob )
{
struct ieee80211_frame *hdr = iob->data;
struct ieee80211_assoc_resp *assoc =
( struct ieee80211_assoc_resp * ) hdr->data;
net80211_process_capab ( dev, assoc->capability );
net80211_process_ie ( dev, assoc->info_element, iob->tail );
if ( assoc->status != IEEE80211_STATUS_SUCCESS ) {
DBGC ( dev, "802.11 %p association failed: status %d\n",
dev, assoc->status );
net80211_set_state ( dev, NET80211_WAITING, 0,
assoc->status );
return;
}
/* ESSID was filled before the association request was sent */
memcpy ( dev->bssid, hdr->addr3, ETH_ALEN );
dev->aid = assoc->aid;
net80211_set_state ( dev, NET80211_WAITING, NET80211_ASSOCIATED,
IEEE80211_STATUS_SUCCESS );
}
/**
* Send 802.11 disassociation frame
*
* @v dev 802.11 device
* @v reason Reason for disassociation
* @ret rc Return status code
*/
static int net80211_send_disassoc ( struct net80211_device *dev, int reason )
{
struct io_buffer *iob = alloc_iob ( 64 );
struct ieee80211_disassoc *disassoc;
if ( ! ( dev->state & NET80211_ASSOCIATED ) )
return -EINVAL;
net80211_set_state ( dev, NET80211_ASSOCIATED, 0, 0 );
iob_reserve ( iob, IEEE80211_TYP_FRAME_HEADER_LEN );
disassoc = iob_put ( iob, sizeof ( *disassoc ) );
disassoc->reason = reason;
return net80211_tx_mgmt ( dev, IEEE80211_STYPE_DISASSOC, dev->bssid,
iob );
}
/** Smoothing factor (1-7) for link quality calculation */
#define LQ_SMOOTH 7
/**
* Update link quality information based on received beacon
*
* @v dev 802.11 device
* @v iob I/O buffer containing beacon
* @ret rc Return status code
*/
static void net80211_update_link_quality ( struct net80211_device *dev,
struct io_buffer *iob )
{
struct ieee80211_frame *hdr = iob->data;
struct ieee80211_beacon *beacon;
u32 dt, rxi;
if ( ! ( dev->state & NET80211_ASSOCIATED ) )
return;
beacon = ( struct ieee80211_beacon * ) hdr->data;
dt = ( u32 ) ( beacon->timestamp - dev->last_beacon_timestamp );
rxi = dev->rx_beacon_interval;
rxi = ( LQ_SMOOTH * rxi ) + ( ( 8 - LQ_SMOOTH ) * dt );
dev->rx_beacon_interval = rxi >> 3;
dev->last_beacon_timestamp = beacon->timestamp;
}
/**
* Handle receipt of 802.11 management frame
*
* @v dev 802.11 device
* @v iob I/O buffer
* @v signal Signal strength of received frame
*/
static void net80211_handle_mgmt ( struct net80211_device *dev,
struct io_buffer *iob, int signal )
{
struct ieee80211_frame *hdr = iob->data;
struct ieee80211_disassoc *disassoc;
u16 stype = hdr->fc & IEEE80211_FC_SUBTYPE;
int keep = 0;
int is_deauth = ( stype == IEEE80211_STYPE_DEAUTH );
if ( ( hdr->fc & IEEE80211_FC_TYPE ) != IEEE80211_TYPE_MGMT ) {
free_iob ( iob );
return; /* only handle management frames */
}
switch ( stype ) {
/* We reconnect on deauthentication and disassociation. */
case IEEE80211_STYPE_DEAUTH:
case IEEE80211_STYPE_DISASSOC:
disassoc = ( struct ieee80211_disassoc * ) hdr->data;
net80211_set_state ( dev, is_deauth ? NET80211_AUTHENTICATED :
NET80211_ASSOCIATED, 0,
NET80211_IS_REASON | disassoc->reason );
DBGC ( dev, "802.11 %p %s: reason %d\n",
dev, is_deauth ? "deauthenticated" : "disassociated",
disassoc->reason );
/* Try to reassociate, in case it's transient. */
net80211_autoassociate ( dev );
break;
/* We handle authentication and association. */
case IEEE80211_STYPE_AUTH:
if ( ! ( dev->state & NET80211_AUTHENTICATED ) )
net80211_handle_auth ( dev, iob );
break;
case IEEE80211_STYPE_ASSOC_RESP:
case IEEE80211_STYPE_REASSOC_RESP:
if ( ! ( dev->state & NET80211_ASSOCIATED ) )
net80211_handle_assoc_reply ( dev, iob );
break;
/* We pass probes and beacons onto network scanning
code. Pass actions for future extensibility. */
case IEEE80211_STYPE_BEACON:
net80211_update_link_quality ( dev, iob );
/* fall through */
case IEEE80211_STYPE_PROBE_RESP:
case IEEE80211_STYPE_ACTION:
if ( dev->keep_mgmt ) {
struct net80211_rx_info *rxinf;
rxinf = zalloc ( sizeof ( *rxinf ) );
if ( ! rxinf ) {
DBGC ( dev, "802.11 %p out of memory\n", dev );
break;
}
rxinf->signal = signal;
list_add_tail ( &iob->list, &dev->mgmt_queue );
list_add_tail ( &rxinf->list, &dev->mgmt_info_queue );
keep = 1;
}
break;
case IEEE80211_STYPE_PROBE_REQ:
/* Some nodes send these broadcast. Ignore them. */
break;
case IEEE80211_STYPE_ASSOC_REQ:
case IEEE80211_STYPE_REASSOC_REQ:
/* We should never receive these, only send them. */
DBGC ( dev, "802.11 %p received strange management request "
"(%04x)\n", dev, stype );
break;
default:
DBGC ( dev, "802.11 %p received unimplemented management "
"packet (%04x)\n", dev, stype );
break;
}
if ( ! keep )
free_iob ( iob );
}
/* ---------- Packet handling functions ---------- */
/**
* Free buffers used by 802.11 fragment cache entry
*
* @v dev 802.11 device
* @v fcid Fragment cache entry index
*
* After this function, the referenced entry will be marked unused.
*/
static void net80211_free_frags ( struct net80211_device *dev, int fcid )
{
int j;
struct net80211_frag_cache *frag = &dev->frags[fcid];
for ( j = 0; j < 16; j++ ) {
if ( frag->iob[j] ) {
free_iob ( frag->iob[j] );
frag->iob[j] = NULL;
}
}
frag->seqnr = 0;
frag->start_ticks = 0;
frag->in_use = 0;
}
/**
* Accumulate 802.11 fragments into one I/O buffer
*
* @v dev 802.11 device
* @v fcid Fragment cache entry index
* @v nfrags Number of fragments received
* @v size Sum of sizes of all fragments, including headers
* @ret iob I/O buffer containing reassembled packet
*
* This function does not free the fragment buffers.
*/
static struct io_buffer *net80211_accum_frags ( struct net80211_device *dev,
int fcid, int nfrags, int size )
{
struct net80211_frag_cache *frag = &dev->frags[fcid];
int hdrsize = IEEE80211_TYP_FRAME_HEADER_LEN;
int nsize = size - hdrsize * ( nfrags - 1 );
int i;
struct io_buffer *niob = alloc_iob ( nsize );
struct ieee80211_frame *hdr;
/* Add the header from the first one... */
memcpy ( iob_put ( niob, hdrsize ), frag->iob[0]->data, hdrsize );
/* ... and all the data from all of them. */
for ( i = 0; i < nfrags; i++ ) {
int len = iob_len ( frag->iob[i] ) - hdrsize;
memcpy ( iob_put ( niob, len ),
frag->iob[i]->data + hdrsize, len );
}
/* Turn off the fragment bit. */
hdr = niob->data;
hdr->fc &= ~IEEE80211_FC_MORE_FRAG;
return niob;
}
/**
* Handle receipt of 802.11 fragment
*
* @v dev 802.11 device
* @v iob I/O buffer containing fragment
* @v signal Signal strength with which fragment was received
*/
static void net80211_rx_frag ( struct net80211_device *dev,
struct io_buffer *iob, int signal )
{
struct ieee80211_frame *hdr = iob->data;
int fragnr = IEEE80211_FRAG ( hdr->seq );
if ( fragnr == 0 && ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
/* start a frag cache entry */
int i, newest = -1;
u32 curr_ticks = currticks(), newest_ticks = 0;
u32 timeout = ticks_per_sec() * NET80211_FRAG_TIMEOUT;
for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
if ( dev->frags[i].in_use == 0 )
break;
if ( dev->frags[i].start_ticks + timeout >=
curr_ticks ) {
net80211_free_frags ( dev, i );
break;
}
if ( dev->frags[i].start_ticks > newest_ticks ) {
newest = i;
newest_ticks = dev->frags[i].start_ticks;
}
}
/* If we're being sent more concurrent fragmented
packets than we can handle, drop the newest so the
older ones have time to complete. */
if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
i = newest;
net80211_free_frags ( dev, i );
}
dev->frags[i].in_use = 1;
dev->frags[i].seqnr = IEEE80211_SEQNR ( hdr->seq );
dev->frags[i].start_ticks = currticks();
dev->frags[i].iob[0] = iob;
return;
} else {
int i;
for ( i = 0; i < NET80211_NR_CONCURRENT_FRAGS; i++ ) {
if ( dev->frags[i].in_use && dev->frags[i].seqnr ==
IEEE80211_SEQNR ( hdr->seq ) )
break;
}
if ( i == NET80211_NR_CONCURRENT_FRAGS ) {
/* Drop non-first not-in-cache fragments */
DBGC ( dev, "802.11 %p dropped fragment fc=%04x "
"seq=%04x\n", dev, hdr->fc, hdr->seq );
free_iob ( iob );
return;
}
dev->frags[i].iob[fragnr] = iob;
if ( ! ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
int j, size = 0;
for ( j = 0; j < fragnr; j++ ) {
size += iob_len ( dev->frags[i].iob[j] );
if ( dev->frags[i].iob[j] == NULL )
break;
}
if ( j == fragnr ) {
/* We've got everything */
struct io_buffer *niob =
net80211_accum_frags ( dev, i, fragnr,
size );
net80211_free_frags ( dev, i );
net80211_rx ( dev, niob, signal, 0 );
} else {
DBGC ( dev, "802.11 %p dropping fragmented "
"packet due to out-of-order arrival, "
"fc=%04x seq=%04x\n", dev, hdr->fc,
hdr->seq );
net80211_free_frags ( dev, i );
}
}
}
}
/**
* Handle receipt of 802.11 frame
*
* @v dev 802.11 device
* @v iob I/O buffer
* @v signal Received signal strength
* @v rate Bitrate at which frame was received, in 100 kbps units
*
* If the rate or signal is unknown, 0 should be passed.
*/
void net80211_rx ( struct net80211_device *dev, struct io_buffer *iob,
int signal, u16 rate )
{
struct ieee80211_frame *hdr = iob->data;
u16 type = hdr->fc & IEEE80211_FC_TYPE;
if ( ( hdr->fc & IEEE80211_FC_VERSION ) != IEEE80211_THIS_VERSION )
goto drop; /* drop invalid-version packets */
if ( type == IEEE80211_TYPE_CTRL )
goto drop; /* we don't handle control packets,
the hardware does */
if ( dev->last_rx_seq == hdr->seq )
goto drop; /* avoid duplicate packet */
dev->last_rx_seq = hdr->seq;
if ( dev->hw->flags & NET80211_HW_RX_HAS_FCS ) {
/* discard the FCS */
iob_unput ( iob, 4 );
}
if ( hdr->fc & IEEE80211_FC_PROTECTED ) {
struct io_buffer *niob;
if ( ! dev->crypto )
goto drop; /* can't decrypt packets on an open network */
niob = dev->crypto->decrypt ( dev->crypto, iob );
if ( ! niob )
goto drop; /* drop failed decryption */
free_iob ( iob );
iob = niob;
}
dev->last_signal = signal;
/* Fragments go into the frag cache or get dropped. */
if ( IEEE80211_FRAG ( hdr->seq ) != 0
|| ( hdr->fc & IEEE80211_FC_MORE_FRAG ) ) {
net80211_rx_frag ( dev, iob, signal );
return;
}
/* Management frames get handled, enqueued, or dropped. */
if ( type == IEEE80211_TYPE_MGMT ) {
net80211_handle_mgmt ( dev, iob, signal );
return;
}
/* Data frames get dropped or sent to the net_device. */
if ( ( hdr->fc & IEEE80211_FC_SUBTYPE ) != IEEE80211_STYPE_DATA )
goto drop; /* drop QoS, CFP, or null data packets */
/* Update rate-control algorithm */
if ( dev->rctl )
rc80211_update_rx ( dev, hdr->fc & IEEE80211_FC_RETRY, rate );
/* Pass packet onward */
if ( netdev_link_ok ( dev->netdev ) ) {
netdev_rx ( dev->netdev, iob );
return;
}
drop:
DBGC2 ( dev, "802.11 %p dropped packet fc=%04x seq=%04x\n", dev,
hdr->fc, hdr->seq );
free_iob ( iob );
return;
}
/** Indicate an error in receiving a packet
*
* @v dev 802.11 device
* @v iob I/O buffer with received packet, or NULL
* @v rc Error code
*
* This logs the error with the wrapping net_device, and frees iob if
* it is passed.
*/
void net80211_rx_err ( struct net80211_device *dev,
struct io_buffer *iob, int rc )
{
netdev_rx_err ( dev->netdev, iob, rc );
}
/** Indicate the completed transmission of a packet
*
* @v dev 802.11 device
* @v iob I/O buffer of transmitted packet
* @v retries Number of times this packet was retransmitted
* @v rc Error code, or 0 for success
*
* This logs an error with the wrapping net_device if one occurred,
* and removes and frees the I/O buffer from its TX queue. The
* provided retry information is used to tune our transmission rate.
*
* If the packet did not need to be retransmitted because it was
* properly ACKed the first time, @a retries should be 0.
*/
void net80211_tx_complete ( struct net80211_device *dev,
struct io_buffer *iob, int retries, int rc )
{
/* Update rate-control algorithm */
if ( dev->rctl )
rc80211_update_tx ( dev, retries, rc );
/* Pass completion onward */
netdev_tx_complete_err ( dev->netdev, iob, rc );
}
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