1 /*
2 * This file contains helper code to handle channel
3 * settings and keeping track of what is possible at
4 * any point in time.
5 *
6 * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
7 */
8
9 #include <linux/export.h>
10 #include <net/cfg80211.h>
11 #include "core.h"
12
13 struct ieee80211_channel *
rdev_freq_to_chan(struct cfg80211_registered_device * rdev,int freq,enum nl80211_channel_type channel_type)14 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
15 int freq, enum nl80211_channel_type channel_type)
16 {
17 struct ieee80211_channel *chan;
18 struct ieee80211_sta_ht_cap *ht_cap;
19
20 chan = ieee80211_get_channel(&rdev->wiphy, freq);
21
22 /* Primary channel not allowed */
23 if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
24 return NULL;
25
26 if (channel_type == NL80211_CHAN_HT40MINUS &&
27 chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
28 return NULL;
29 else if (channel_type == NL80211_CHAN_HT40PLUS &&
30 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
31 return NULL;
32
33 ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
34
35 if (channel_type != NL80211_CHAN_NO_HT) {
36 if (!ht_cap->ht_supported)
37 return NULL;
38
39 if (channel_type != NL80211_CHAN_HT20 &&
40 (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
41 ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
42 return NULL;
43 }
44
45 return chan;
46 }
47
cfg80211_can_beacon_sec_chan(struct wiphy * wiphy,struct ieee80211_channel * chan,enum nl80211_channel_type channel_type)48 int cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
49 struct ieee80211_channel *chan,
50 enum nl80211_channel_type channel_type)
51 {
52 struct ieee80211_channel *sec_chan;
53 int diff;
54
55 switch (channel_type) {
56 case NL80211_CHAN_HT40PLUS:
57 diff = 20;
58 break;
59 case NL80211_CHAN_HT40MINUS:
60 diff = -20;
61 break;
62 default:
63 return false;
64 }
65
66 sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
67 if (!sec_chan)
68 return false;
69
70 /* we'll need a DFS capability later */
71 if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
72 IEEE80211_CHAN_PASSIVE_SCAN |
73 IEEE80211_CHAN_NO_IBSS |
74 IEEE80211_CHAN_RADAR))
75 return false;
76
77 return true;
78 }
79 EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
80
cfg80211_set_freq(struct cfg80211_registered_device * rdev,struct wireless_dev * wdev,int freq,enum nl80211_channel_type channel_type)81 int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
82 struct wireless_dev *wdev, int freq,
83 enum nl80211_channel_type channel_type)
84 {
85 struct ieee80211_channel *chan;
86 int result;
87
88 if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
89 wdev = NULL;
90
91 if (wdev) {
92 ASSERT_WDEV_LOCK(wdev);
93
94 if (!netif_running(wdev->netdev))
95 return -ENETDOWN;
96 }
97
98 if (!rdev->ops->set_channel)
99 return -EOPNOTSUPP;
100
101 chan = rdev_freq_to_chan(rdev, freq, channel_type);
102 if (!chan)
103 return -EINVAL;
104
105 /* Both channels should be able to initiate communication */
106 if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
107 wdev->iftype == NL80211_IFTYPE_AP ||
108 wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
109 wdev->iftype == NL80211_IFTYPE_MESH_POINT ||
110 wdev->iftype == NL80211_IFTYPE_P2P_GO)) {
111 switch (channel_type) {
112 case NL80211_CHAN_HT40PLUS:
113 case NL80211_CHAN_HT40MINUS:
114 if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan,
115 channel_type)) {
116 printk(KERN_DEBUG
117 "cfg80211: Secondary channel not "
118 "allowed to initiate communication\n");
119 return -EINVAL;
120 }
121 break;
122 default:
123 break;
124 }
125 }
126
127 result = rdev->ops->set_channel(&rdev->wiphy,
128 wdev ? wdev->netdev : NULL,
129 chan, channel_type);
130 if (result)
131 return result;
132
133 if (wdev)
134 wdev->channel = chan;
135
136 return 0;
137 }
138