fix: select monitor-channel callback from cfg80211 header type

Keep the internal monitor-channel API independent of kernel versions and select a correctly typed cfg80211 adapter at compile time. This covers Ubuntu 6.8.0-147 and stable/backports without release-string heuristics or function-pointer casts.

Validation: reproduced the original failure on Ubuntu 6.8.0-147; all three modules build on 6.8.0-146, 6.8.0-147 and 6.17.0-14. Fixes #107.

OPENWRT.md

@@ -49,8 +49,10 @@ it to the host kernel version or redefine `LINUX_VERSION_CODE`.
 ## Compatibility scope
 
 The override selects the wireless API changes since Linux 6.12, including
-monitor-channel callbacks, radio/link arguments, radar notifications and
+radio/link arguments, radar notifications and newer cfg80211 callbacks.
-newer cfg80211 callbacks. Timer, USB, memory-management and module namespace
+The monitor-channel callback is selected from the actual cfg80211 header type
+so distribution backports also work without changing the version override.
+Timer, USB, memory-management and module namespace
 checks continue to use the target kernel version. Older target kernels with
 newer backports may need additional wireless API adaptations.
 

drivers/aic8800/aic8800_fdrv/aic_priv_cmd.c

@@ -1832,19 +1832,10 @@ void set_vendor_extension_ie(char *command){
 
 }
 #endif//CONFIG_SET_VENDOR_EXTENSION_IE
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy, struct net_device *dev,
-                                             struct cfg80211_chan_def *chandef);
-#else
 int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy,
                                              struct cfg80211_chan_def *chandef);
-#endif
 int rwnx_atoi2(char *value, int c_len);
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-void set_mon_chan(struct rwnx_vif *vif, struct net_device *dev, char *parameter)
-#else
 void set_mon_chan(struct rwnx_vif *vif, char *parameter)
-#endif
 {
     struct cfg80211_chan_def *chandef = NULL;
     int freq = 0;
@@ -1867,11 +1858,7 @@ void set_mon_chan(struct rwnx_vif *vif, char *parameter)
     chandef->center_freq1 = chandef->chan->center_freq;
     chandef->center_freq2 = 0;
 
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-    rwnx_cfg80211_set_monitor_channel_(vif->rwnx_hw->wiphy, dev, chandef);
-#else
     rwnx_cfg80211_set_monitor_channel_(vif->rwnx_hw->wiphy, chandef);
-#endif
 
     vfree(chandef->chan);
     vfree(chandef);
@@ -2136,11 +2123,7 @@ int android_priv_cmd(struct net_device *net, struct ifreq *ifr, int cmd)
 	    char *set_parameter;
         skip = strlen(CMD_SET_MON_FREQ) + 1;
 		set_parameter = command + skip;
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-	    set_mon_chan(vif, net, set_parameter);
-#else
 	    set_mon_chan(vif, set_parameter);
-#endif
 		ret = 0;
 		goto exit;
     }

drivers/aic8800/aic8800_fdrv/aic_priv_cmd.h

@@ -62,11 +62,7 @@ int get_cs_info(struct rwnx_vif *vif, u8 *mac_addr, u8 *val);
 unsigned int command_strtoul(const char *cp, char **endp, unsigned int base);
 int str_starts(const char *str, const char *start);
 int handle_private_cmd(struct net_device *net, char *command, u32 cmd_len);
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-void set_mon_chan(struct rwnx_vif *vif, struct net_device *dev, char *parameter);
-#else
 void set_mon_chan(struct rwnx_vif *vif, char *parameter);
-#endif
 
 #endif /* _AIC_PRIV_CMD_H_ */
 

drivers/aic8800/aic8800_fdrv/rwnx_compat.h

@@ -28,28 +28,6 @@
 #define AICWF_CFG80211_VERSION_CODE LINUX_VERSION_CODE
 #endif
 
-/*
- * cfg80211_ops.set_monitor_channel() gained a "struct net_device *dev"
- * parameter. The change went into mainline 6.13, but it was also
- * backported to the 6.12 stable series starting with 6.12.101, so a
- * plain ">= 6.13.0" test misses 6.12.101 and later. Those kernels then
- * compile against the old prototype, which is fatal with
- * -Wincompatible-pointer-types:
- *
- *   rwnx_main.c: error: initialization of
- *     'int (*)(struct wiphy *, struct net_device *, struct cfg80211_chan_def *)'
- *     from incompatible pointer type
- *     'int (*)(struct wiphy *, struct cfg80211_chan_def *)'
- *
- * Debian 13 (6.12.107) is one such kernel. The 6.12.101 threshold
- * covers both the backport and mainline, and leaves 6.11 and earlier
- * 6.12.x on the old prototype. Keep the check in one place so every
- * consumer stays in sync.
- */
-#if AICWF_CFG80211_VERSION_CODE >= KERNEL_VERSION(6, 12, 101)
-#define AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-#endif
-
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 10, 0)
 #error "Minimum kernel version supported is 3.10"
 #endif

drivers/aic8800/aic8800_fdrv/rwnx_main.c

@@ -4451,13 +4451,8 @@ cfg80211_chandef_identical(const struct cfg80211_chan_def *chandef1,
 }
 #endif
 
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-static int rwnx_cfg80211_set_monitor_channel(struct wiphy *wiphy, struct net_device *dev,
-                                             struct cfg80211_chan_def *chandef)
-#else
 static int rwnx_cfg80211_set_monitor_channel(struct wiphy *wiphy,
                                              struct cfg80211_chan_def *chandef)
-#endif
 {
     struct rwnx_hw *rwnx_hw = wiphy_priv(wiphy);
     struct rwnx_vif *rwnx_vif;
@@ -4511,21 +4506,19 @@ static int rwnx_cfg80211_set_monitor_channel(struct wiphy *wiphy,
 }
 
 
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
+/* Newer cfg80211 stacks pass dev; the firmware still has one monitor vif. */
-int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy,
+static int rwnx_cfg80211_set_monitor_channel_with_dev(struct wiphy *wiphy,
                                                     struct net_device *dev,
                                                     struct cfg80211_chan_def *chandef)
 {
-    return rwnx_cfg80211_set_monitor_channel(wiphy, dev, chandef);
+    return rwnx_cfg80211_set_monitor_channel(wiphy, chandef);
 }
-#else
+
 int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy,
                                              struct cfg80211_chan_def *chandef)
 {
     return rwnx_cfg80211_set_monitor_channel(wiphy, chandef);
 }
-#endif
-
 
 /**
  * @probe_peer: probe an associated client. Before 7.3 the driver returns a
@@ -5119,11 +5112,7 @@ static int rwnx_cfg80211_get_channel(struct wiphy *wiphy,
     if (rwnx_vif->vif_index == rwnx_hw->monitor_vif)
     {
         //retrieve channel from firmware
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-        rwnx_cfg80211_set_monitor_channel(wiphy, wdev->netdev, NULL);
-#else
         rwnx_cfg80211_set_monitor_channel(wiphy, NULL);
-#endif
     }
 
     //Check if channel context is valid
@@ -6677,7 +6666,14 @@ static struct cfg80211_ops rwnx_cfg80211_ops = {
     .start_ap = rwnx_cfg80211_start_ap,
     .change_beacon = rwnx_cfg80211_change_beacon,
     .stop_ap = rwnx_cfg80211_stop_ap,
-    .set_monitor_channel = rwnx_cfg80211_set_monitor_channel,
+    /* Select the actual header ABI, including distro/stable backports such
+     * as Ubuntu 6.8.0-147 and Linux 6.12.101. No function-pointer casts. */
+    .set_monitor_channel = __builtin_choose_expr(
+        __builtin_types_compatible_p(
+            typeof(((struct cfg80211_ops *)0)->set_monitor_channel),
+            typeof(&rwnx_cfg80211_set_monitor_channel_with_dev)),
+        rwnx_cfg80211_set_monitor_channel_with_dev,
+        rwnx_cfg80211_set_monitor_channel),
 #if AICWF_CFG80211_VERSION_CODE >= KERNEL_VERSION(7, 3, 0)
     .probe_peer = rwnx_cfg80211_probe_client,
 #else

drivers/aic8800/aic8800_fdrv/rwnx_main.h

@@ -91,14 +91,8 @@ void aicwf_p2p_alive_timeout(struct timer_list *t);
 int rwnx_send_check_p2p(struct cfg80211_scan_request *param);
 void apm_staloss_work_process(struct work_struct *work);
 void apm_probe_sta_work_process(struct work_struct *work);
-#ifdef AICWF_CFG80211_SET_MONITOR_CHANNEL_HAS_DEV
-int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy,
-                                             struct net_device *dev,
-                                             struct cfg80211_chan_def *chandef);
-#else
 int rwnx_cfg80211_set_monitor_channel_(struct wiphy *wiphy,
                                              struct cfg80211_chan_def *chandef);
-#endif
 #if AICWF_CFG80211_VERSION_CODE >= KERNEL_VERSION(7, 3, 0)
 int rwnx_cfg80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
             const u8 *peer, u64 cookie);