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linux/net/wireless/util.c

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/*
* Wireless utility functions
*
* Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net>
*/
#include <linux/bitops.h>
#include <linux/etherdevice.h>
#include <net/cfg80211.h>
#include <net/ip.h>
#include "core.h"
struct ieee80211_rate *
ieee80211_get_response_rate(struct ieee80211_supported_band *sband,
u32 basic_rates, int bitrate)
{
struct ieee80211_rate *result = &sband->bitrates[0];
int i;
for (i = 0; i < sband->n_bitrates; i++) {
if (!(basic_rates & BIT(i)))
continue;
if (sband->bitrates[i].bitrate > bitrate)
continue;
result = &sband->bitrates[i];
}
return result;
}
EXPORT_SYMBOL(ieee80211_get_response_rate);
int ieee80211_channel_to_frequency(int chan)
{
if (chan < 14)
return 2407 + chan * 5;
if (chan == 14)
return 2484;
/* FIXME: 802.11j 17.3.8.3.2 */
return (chan + 1000) * 5;
}
EXPORT_SYMBOL(ieee80211_channel_to_frequency);
int ieee80211_frequency_to_channel(int freq)
{
if (freq == 2484)
return 14;
if (freq < 2484)
return (freq - 2407) / 5;
/* FIXME: 802.11j 17.3.8.3.2 */
return freq/5 - 1000;
}
EXPORT_SYMBOL(ieee80211_frequency_to_channel);
struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy,
int freq)
{
enum ieee80211_band band;
struct ieee80211_supported_band *sband;
int i;
for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
sband = wiphy->bands[band];
if (!sband)
continue;
for (i = 0; i < sband->n_channels; i++) {
if (sband->channels[i].center_freq == freq)
return &sband->channels[i];
}
}
return NULL;
}
EXPORT_SYMBOL(__ieee80211_get_channel);
static void set_mandatory_flags_band(struct ieee80211_supported_band *sband,
enum ieee80211_band band)
{
int i, want;
switch (band) {
case IEEE80211_BAND_5GHZ:
want = 3;
for (i = 0; i < sband->n_bitrates; i++) {
if (sband->bitrates[i].bitrate == 60 ||
sband->bitrates[i].bitrate == 120 ||
sband->bitrates[i].bitrate == 240) {
sband->bitrates[i].flags |=
IEEE80211_RATE_MANDATORY_A;
want--;
}
}
WARN_ON(want);
break;
case IEEE80211_BAND_2GHZ:
want = 7;
for (i = 0; i < sband->n_bitrates; i++) {
if (sband->bitrates[i].bitrate == 10) {
sband->bitrates[i].flags |=
IEEE80211_RATE_MANDATORY_B |
IEEE80211_RATE_MANDATORY_G;
want--;
}
if (sband->bitrates[i].bitrate == 20 ||
sband->bitrates[i].bitrate == 55 ||
sband->bitrates[i].bitrate == 110 ||
sband->bitrates[i].bitrate == 60 ||
sband->bitrates[i].bitrate == 120 ||
sband->bitrates[i].bitrate == 240) {
sband->bitrates[i].flags |=
IEEE80211_RATE_MANDATORY_G;
want--;
}
if (sband->bitrates[i].bitrate != 10 &&
sband->bitrates[i].bitrate != 20 &&
sband->bitrates[i].bitrate != 55 &&
sband->bitrates[i].bitrate != 110)
sband->bitrates[i].flags |=
IEEE80211_RATE_ERP_G;
}
WARN_ON(want != 0 && want != 3 && want != 6);
break;
case IEEE80211_NUM_BANDS:
WARN_ON(1);
break;
}
}
void ieee80211_set_bitrate_flags(struct wiphy *wiphy)
{
enum ieee80211_band band;
for (band = 0; band < IEEE80211_NUM_BANDS; band++)
if (wiphy->bands[band])
set_mandatory_flags_band(wiphy->bands[band], band);
}
int cfg80211_validate_key_settings(struct key_params *params, int key_idx,
const u8 *mac_addr)
{
if (key_idx > 5)
return -EINVAL;
/*
* Disallow pairwise keys with non-zero index unless it's WEP
* (because current deployments use pairwise WEP keys with
* non-zero indizes but 802.11i clearly specifies to use zero)
*/
if (mac_addr && key_idx &&
params->cipher != WLAN_CIPHER_SUITE_WEP40 &&
params->cipher != WLAN_CIPHER_SUITE_WEP104)
return -EINVAL;
switch (params->cipher) {
case WLAN_CIPHER_SUITE_WEP40:
if (params->key_len != WLAN_KEY_LEN_WEP40)
return -EINVAL;
break;
case WLAN_CIPHER_SUITE_TKIP:
if (params->key_len != WLAN_KEY_LEN_TKIP)
return -EINVAL;
break;
case WLAN_CIPHER_SUITE_CCMP:
if (params->key_len != WLAN_KEY_LEN_CCMP)
return -EINVAL;
break;
case WLAN_CIPHER_SUITE_WEP104:
if (params->key_len != WLAN_KEY_LEN_WEP104)
return -EINVAL;
break;
case WLAN_CIPHER_SUITE_AES_CMAC:
if (params->key_len != WLAN_KEY_LEN_AES_CMAC)
return -EINVAL;
break;
default:
return -EINVAL;
}
if (params->seq) {
switch (params->cipher) {
case WLAN_CIPHER_SUITE_WEP40:
case WLAN_CIPHER_SUITE_WEP104:
/* These ciphers do not use key sequence */
return -EINVAL;
case WLAN_CIPHER_SUITE_TKIP:
case WLAN_CIPHER_SUITE_CCMP:
case WLAN_CIPHER_SUITE_AES_CMAC:
if (params->seq_len != 6)
return -EINVAL;
break;
}
}
return 0;
}
/* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
/* Ethernet-II snap header (RFC1042 for most EtherTypes) */
const unsigned char rfc1042_header[] __aligned(2) =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
EXPORT_SYMBOL(rfc1042_header);
/* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
const unsigned char bridge_tunnel_header[] __aligned(2) =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
EXPORT_SYMBOL(bridge_tunnel_header);
unsigned int ieee80211_hdrlen(__le16 fc)
{
unsigned int hdrlen = 24;
if (ieee80211_is_data(fc)) {
if (ieee80211_has_a4(fc))
hdrlen = 30;
if (ieee80211_is_data_qos(fc))
hdrlen += IEEE80211_QOS_CTL_LEN;
goto out;
}
if (ieee80211_is_ctl(fc)) {
/*
* ACK and CTS are 10 bytes, all others 16. To see how
* to get this condition consider
* subtype mask: 0b0000000011110000 (0x00F0)
* ACK subtype: 0b0000000011010000 (0x00D0)
* CTS subtype: 0b0000000011000000 (0x00C0)
* bits that matter: ^^^ (0x00E0)
* value of those: 0b0000000011000000 (0x00C0)
*/
if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
hdrlen = 10;
else
hdrlen = 16;
}
out:
return hdrlen;
}
EXPORT_SYMBOL(ieee80211_hdrlen);
unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
{
const struct ieee80211_hdr *hdr =
(const struct ieee80211_hdr *)skb->data;
unsigned int hdrlen;
if (unlikely(skb->len < 10))
return 0;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (unlikely(hdrlen > skb->len))
return 0;
return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
{
int ae = meshhdr->flags & MESH_FLAGS_AE;
/* 7.1.3.5a.2 */
switch (ae) {
case 0:
return 6;
case 1:
return 12;
case 2:
return 18;
case 3:
return 24;
default:
return 6;
}
}
int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
enum nl80211_iftype iftype)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
u16 hdrlen, ethertype;
u8 *payload;
u8 dst[ETH_ALEN];
u8 src[ETH_ALEN] __aligned(2);
if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
return -1;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
/* convert IEEE 802.11 header + possible LLC headers into Ethernet
* header
* IEEE 802.11 address fields:
* ToDS FromDS Addr1 Addr2 Addr3 Addr4
* 0 0 DA SA BSSID n/a
* 0 1 DA BSSID SA n/a
* 1 0 BSSID SA DA n/a
* 1 1 RA TA DA SA
*/
memcpy(dst, ieee80211_get_DA(hdr), ETH_ALEN);
memcpy(src, ieee80211_get_SA(hdr), ETH_ALEN);
switch (hdr->frame_control &
cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
case cpu_to_le16(IEEE80211_FCTL_TODS):
if (unlikely(iftype != NL80211_IFTYPE_AP &&
iftype != NL80211_IFTYPE_AP_VLAN))
return -1;
break;
case cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
if (unlikely(iftype != NL80211_IFTYPE_WDS &&
iftype != NL80211_IFTYPE_MESH_POINT))
return -1;
if (iftype == NL80211_IFTYPE_MESH_POINT) {
struct ieee80211s_hdr *meshdr =
(struct ieee80211s_hdr *) (skb->data + hdrlen);
hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
memcpy(dst, meshdr->eaddr1, ETH_ALEN);
memcpy(src, meshdr->eaddr2, ETH_ALEN);
}
}
break;
case cpu_to_le16(IEEE80211_FCTL_FROMDS):
if (iftype != NL80211_IFTYPE_STATION ||
(is_multicast_ether_addr(dst) &&
!compare_ether_addr(src, addr)))
return -1;
break;
case cpu_to_le16(0):
if (iftype != NL80211_IFTYPE_ADHOC)
return -1;
break;
}
if (unlikely(skb->len - hdrlen < 8))
return -1;
payload = skb->data + hdrlen;
ethertype = (payload[6] << 8) | payload[7];
if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
compare_ether_addr(payload, bridge_tunnel_header) == 0)) {
/* remove RFC1042 or Bridge-Tunnel encapsulation and
* replace EtherType */
skb_pull(skb, hdrlen + 6);
memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
} else {
struct ethhdr *ehdr;
__be16 len;
skb_pull(skb, hdrlen);
len = htons(skb->len);
ehdr = (struct ethhdr *) skb_push(skb, sizeof(struct ethhdr));
memcpy(ehdr->h_dest, dst, ETH_ALEN);
memcpy(ehdr->h_source, src, ETH_ALEN);
ehdr->h_proto = len;
}
return 0;
}
EXPORT_SYMBOL(ieee80211_data_to_8023);
int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
enum nl80211_iftype iftype, u8 *bssid, bool qos)
{
struct ieee80211_hdr hdr;
u16 hdrlen, ethertype;
__le16 fc;
const u8 *encaps_data;
int encaps_len, skip_header_bytes;
int nh_pos, h_pos;
int head_need;
if (unlikely(skb->len < ETH_HLEN))
return -EINVAL;
nh_pos = skb_network_header(skb) - skb->data;
h_pos = skb_transport_header(skb) - skb->data;
/* convert Ethernet header to proper 802.11 header (based on
* operation mode) */
ethertype = (skb->data[12] << 8) | skb->data[13];
fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
switch (iftype) {
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_AP_VLAN:
fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
/* DA BSSID SA */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, addr, ETH_ALEN);
memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
hdrlen = 24;
break;
case NL80211_IFTYPE_STATION:
fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
/* BSSID SA DA */
memcpy(hdr.addr1, bssid, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, skb->data, ETH_ALEN);
hdrlen = 24;
break;
case NL80211_IFTYPE_ADHOC:
/* DA SA BSSID */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, bssid, ETH_ALEN);
hdrlen = 24;
break;
default:
return -EOPNOTSUPP;
}
if (qos) {
fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
hdrlen += 2;
}
hdr.frame_control = fc;
hdr.duration_id = 0;
hdr.seq_ctrl = 0;
skip_header_bytes = ETH_HLEN;
if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
encaps_data = bridge_tunnel_header;
encaps_len = sizeof(bridge_tunnel_header);
skip_header_bytes -= 2;
} else if (ethertype > 0x600) {
encaps_data = rfc1042_header;
encaps_len = sizeof(rfc1042_header);
skip_header_bytes -= 2;
} else {
encaps_data = NULL;
encaps_len = 0;
}
skb_pull(skb, skip_header_bytes);
nh_pos -= skip_header_bytes;
h_pos -= skip_header_bytes;
head_need = hdrlen + encaps_len - skb_headroom(skb);
if (head_need > 0 || skb_cloned(skb)) {
head_need = max(head_need, 0);
if (head_need)
skb_orphan(skb);
if (pskb_expand_head(skb, head_need, 0, GFP_ATOMIC)) {
printk(KERN_ERR "failed to reallocate Tx buffer\n");
return -ENOMEM;
}
skb->truesize += head_need;
}
if (encaps_data) {
memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
nh_pos += encaps_len;
h_pos += encaps_len;
}
memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
nh_pos += hdrlen;
h_pos += hdrlen;
/* Update skb pointers to various headers since this modified frame
* is going to go through Linux networking code that may potentially
* need things like pointer to IP header. */
skb_set_mac_header(skb, 0);
skb_set_network_header(skb, nh_pos);
skb_set_transport_header(skb, h_pos);
return 0;
}
EXPORT_SYMBOL(ieee80211_data_from_8023);
/* Given a data frame determine the 802.1p/1d tag to use. */
unsigned int cfg80211_classify8021d(struct sk_buff *skb)
{
unsigned int dscp;
/* skb->priority values from 256->263 are magic values to
* directly indicate a specific 802.1d priority. This is used
* to allow 802.1d priority to be passed directly in from VLAN
* tags, etc.
*/
if (skb->priority >= 256 && skb->priority <= 263)
return skb->priority - 256;
switch (skb->protocol) {
case htons(ETH_P_IP):
dscp = ip_hdr(skb)->tos & 0xfc;
break;
default:
return 0;
}
return dscp >> 5;
}
EXPORT_SYMBOL(cfg80211_classify8021d);
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