diff mbox series

hostapd: fix opclass during CSA with DFS channels

Message ID bcafaec62d6d2c7d7de659d2d038d8da@mazekey.pl
State Accepted
Headers show
Series hostapd: fix opclass during CSA with DFS channels | expand

Commit Message

marek@mazekey.pl April 23, 2024, 9:08 a.m. UTC
During CSA with DFS channels, disable, enable interface
is a part of the algorithm.
When interface was enabled old operating class before switch
and new channel were used causing mismatch in
configured_fixed_chan_to_freq function.

Example of log when switch from channel 157 to 108 was triggered:
"Could not convert op_class 124 channel 108 to operating frequency"

Fixes: bb781c763 ("AP: Populate iface->freq before starting AP")

Signed-off-by: Marek Kwaczynski <marek@mazekey.pl>
---
  src/ap/hostapd.c | 7 +++++++
  1 file changed, 7 insertions(+)


@@ -4505,6 +4507,11 @@ hostapd_switch_channel_fallback(struct 
hostapd_iface *iface,
         iface->freq = freq_params->freq;
         iface->conf->channel = freq_params->channel;
         iface->conf->secondary_channel = 
freq_params->sec_channel_offset;
+       ieee80211_freq_to_channel_ext(freq_params->freq, 
freq_params->sec_channel_offset, bw, &op_class, &chan);
+       if (chan != freq_params->channel)
+               wpa_printf(MSG_ERROR, "Channel mismatch: %d -> %d", 
freq_params->channel, chan);
+
+       iface->conf->op_class = op_class;
         hostapd_set_oper_centr_freq_seg0_idx(iface->conf, seg0_idx);
         hostapd_set_oper_centr_freq_seg1_idx(iface->conf, seg1_idx);
         hostapd_set_oper_chwidth(iface->conf, bw);

Comments

Jouni Malinen April 24, 2024, 3:15 p.m. UTC | #1
On Tue, Apr 23, 2024 at 11:08:08AM +0200, marek@mazekey.pl wrote:
> During CSA with DFS channels, disable, enable interface
> is a part of the algorithm.
> When interface was enabled old operating class before switch
> and new channel were used causing mismatch in
> configured_fixed_chan_to_freq function.
> 
> Example of log when switch from channel 157 to 108 was triggered:
> "Could not convert op_class 124 channel 108 to operating frequency"

Could you please provide full hostapd configuration that can trigger
this and a debug log showing this? In particular, I'd like to understand
which country code was used.  This did not seem to show any issues in a
hwsim test setup with country code US, and I'd like to be able to add a
regression test case with this type of fixes.
marek@mazekey.pl April 26, 2024, 10:11 p.m. UTC | #2
We can easy reproduce it when switch to non DFS channel, then to DFS 
channel with different opclass, country code US.

Examples:
a)
- CSA to channel 36
- DFS CSA to channel 100
Could not convert op_class 115 channel 100 to operating frequency
b)
- CSA to channel 157
- DFS CSA to channel 56
Could not convert op_class 124 channel 56 to operating frequency

You can reproduce it with hwsim with small modification:

 From 5edc4a0a21ca677fc142857a349ba2a94b57ca2a Mon Sep 17 00:00:00 2001
 From: Marek Kwaczynski <marek@mazekey.pl>
Date: Sat, 27 Apr 2024 00:01:06 +0200
Subject: [PATCH] tests: hwsim: check CSA between non DFS and DFS chan

Add test to validate CSA between non DFS channel
and DFS channel with different operating class.

Signed-off-by: Marek Kwaczynski <marek@mazekey.pl>
---
  tests/hwsim/test_dfs.py | 35 ++++++++++++++++++++++++++++++++++-
  1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/tests/hwsim/test_dfs.py b/tests/hwsim/test_dfs.py
index d0bae5a66..3be64b147 100644
--- a/tests/hwsim/test_dfs.py
+++ b/tests/hwsim/test_dfs.py
@@ -640,7 +640,7 @@ def test_dfs_chan_switch(dev, apdev):
          if freq != "5260":
              raise Exception("Unexpected frequency")

-        dev[0].connect("dfs", key_mgmt="NONE", scan_freq="5260 5280")
+        dev[0].connect("dfs", key_mgmt="NONE", scan_freq="5260 5280 
5180 5500")
          dev[0].wait_regdom(country_ie=True)
          hwsim_utils.test_connectivity(dev[0], hapd)

@@ -666,6 +666,39 @@ def test_dfs_chan_switch(dev, apdev):

          dev[0].wait_connected(timeout=30)
          hwsim_utils.test_connectivity(dev[0], hapd)
+
+        # Move to non DFS channel: 36, opclass 115
+        if "OK" not in hapd.request("CHAN_SWITCH 5 5180"):
+                raise Exception("CHAN_SWITCH failed")
+        ev = wait_dfs_event(hapd, "AP-CSA-FINISHED", 5)
+
+        if "freq=5180" not in ev:
+            raise Exception("Unexpected channel: " + ev)
+        hwsim_utils.test_connectivity(dev[0], hapd)
+
+        # Move to channel 100, opclass 121
+        if "OK" not in hapd.request("CHAN_SWITCH 5 5500 ht"):
+            raise Exception("CHAN_SWITCH failed")
+        # This results in BSS going down before restart, so the STA is 
expected
+        # to report disconnection.
+        dev[0].wait_disconnected()
+        ev = wait_dfs_event(hapd, "DFS-CAC-START", 5)
+        if "freq=5500" not in ev:
+            raise Exception("Unexpected channel: " + ev)
+        ev = wait_dfs_event(hapd, "DFS-CAC-COMPLETED", 70)
+        if "success=1" not in ev:
+            raise Exception("CAC failed")
+        if "freq=5500" not in ev:
+            raise Exception("Unexpected DFS freq result")
+        ev = hapd.wait_event(["AP-ENABLED"], timeout=5)
+        if not ev:
+            raise Exception("AP setup timed out")
+        freq = hapd.get_status_field("freq")
+        if freq != "5500":
+            raise Exception("Unexpected frequency")
+
+        dev[0].wait_connected(timeout=30)
+        hwsim_utils.test_connectivity(dev[0], hapd)
      finally:
          clear_regdom(hapd, dev)
Jouni Malinen July 13, 2024, 3:28 p.m. UTC | #3
On Tue, Apr 23, 2024 at 11:08:08AM +0200, marek@mazekey.pl wrote:
> During CSA with DFS channels, disable, enable interface
> is a part of the algorithm.
> When interface was enabled old operating class before switch
> and new channel were used causing mismatch in
> configured_fixed_chan_to_freq function.
> 
> Example of log when switch from channel 157 to 108 was triggered:
> "Could not convert op_class 124 channel 108 to operating frequency"
> 
> Fixes: bb781c763 ("AP: Populate iface->freq before starting AP")

Thanks, applied.
diff mbox series

Patch

diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index 130b6ebc6..8d0601e6a 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -4466,6 +4466,8 @@  hostapd_switch_channel_fallback(struct 
hostapd_iface *iface,
  {
         u8 seg0_idx = 0, seg1_idx = 0;
         enum oper_chan_width bw = CONF_OPER_CHWIDTH_USE_HT;
+       u8 op_class;
+       u8 chan;

         wpa_printf(MSG_DEBUG, "Restarting all CSA-related BSSes");