Build fails on Fedora 41 (kernel 6.12.11-200)

[toreanderson]

The module does not build on a fully updated Fedora 41 host:

[fedora@fedora-41 modules]$ make
make -C /lib/modules/6.12.11-200.fc41.x86_64/build M=/home/fedora/nat46/nat46/modules modules
make[1]: Entering directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-netdev.o
/home/fedora/nat46/nat46/modules/nat46-netdev.c: In function ‘nat46_netdev_setup’:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:113:25: error: ‘NETIF_F_NETNS_LOCAL’ undeclared (first use in this function)
  113 |         dev->features = NETIF_F_NETNS_LOCAL;
      |                         ^~~~~~~~~~~~~~~~~~~
/home/fedora/nat46/nat46/modules/nat46-netdev.c:113:25: note: each undeclared identifier is reported only once for each function it appears in
/home/fedora/nat46/nat46/modules/nat46-netdev.c: At top level:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:117:5: warning: no previous prototype for ‘nat46_netdev_create’ [-Wmissing-prototypes]
  117 | int nat46_netdev_create(struct net *net, char *basename, struct net_device **dev)
      |     ^~~~~~~~~~~~~~~~~~~
/home/fedora/nat46/nat46/modules/nat46-netdev.c:173:6: warning: no previous prototype for ‘nat46_netdev_destroy’ [-Wmissing-prototypes]
  173 | void nat46_netdev_destroy(struct net_device *dev)
      |      ^~~~~~~~~~~~~~~~~~~~
In file included from ./include/linux/spinlock.h:305,
                 from ./include/linux/sched.h:2153,
                 from ./include/linux/percpu.h:12,
                 from ./arch/x86/include/asm/msr.h:15,
                 from ./arch/x86/include/asm/tsc.h:10,
                 from ./arch/x86/include/asm/timex.h:6,
                 from ./include/linux/timex.h:67,
                 from ./include/linux/time32.h:13,
                 from ./include/linux/time.h:60,
                 from ./include/linux/skbuff.h:15,
                 from ./include/linux/if_arp.h:22,
                 from /home/fedora/nat46/nat46/modules/nat46-netdev.c:19:
/home/fedora/nat46/nat46/modules/nat46-netdev.c: In function ‘find_dev’:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:196:20: error: ‘dev_base_lock’ undeclared (first use in this function); did you mean ‘device_lock’?
  196 |         read_lock(&dev_base_lock);
      |                    ^~~~~~~~~~~~~
./include/linux/rwlock.h:56:48: note: in definition of macro ‘read_lock’
   56 | #define read_lock(lock)         _raw_read_lock(lock)
      |                                                ^~~~
/home/fedora/nat46/nat46/modules/nat46-netdev.c: In function ‘nat64_show_all_configs’:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:303:20: error: ‘dev_base_lock’ undeclared (first use in this function); did you mean ‘device_lock’?
  303 |         read_lock(&dev_base_lock);
      |                    ^~~~~~~~~~~~~
./include/linux/rwlock.h:56:48: note: in definition of macro ‘read_lock’
   56 | #define read_lock(lock)         _raw_read_lock(lock)
      |                                                ^~~~
/home/fedora/nat46/nat46/modules/nat46-netdev.c: In function ‘nat46_destroy_all’:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:334:28: error: ‘dev_base_lock’ undeclared (first use in this function); did you mean ‘device_lock’?
  334 |                 read_lock(&dev_base_lock);
      |                            ^~~~~~~~~~~~~
./include/linux/rwlock.h:56:48: note: in definition of macro ‘read_lock’
   56 | #define read_lock(lock)         _raw_read_lock(lock)
      |                                                ^~~~
make[3]: *** [scripts/Makefile.build:229: /home/fedora/nat46/nat46/modules/nat46-netdev.o] Error 1
make[2]: *** [/usr/src/kernels/6.12.11-200.fc41.x86_64/Makefile:1977: /home/fedora/nat46/nat46/modules] Error 2
make[1]: *** [Makefile:236: __sub-make] Error 2
make[1]: Leaving directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'
make: *** [Makefile:6: all] Error 2

[angus19]

@toreanderson Please help verify if the fix below works for Fedora 41. Thanks.
Fix build failures observed so far #49

[toreanderson]

There are fewer errors now (the lock stuff appears fixed), but one remains:

[fedora@fedora-41 modules]$ make
make -C /lib/modules/6.12.11-200.fc41.x86_64/build M=/home/fedora/nat46/nat46/modules modules
make[1]: Entering directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-netdev.o
/home/fedora/nat46/nat46/modules/nat46-netdev.c: In function ‘nat46_netdev_setup’:
/home/fedora/nat46/nat46/modules/nat46-netdev.c:122:25: error: ‘NETIF_F_NETNS_LOCAL’ undeclared (first use in this function)
  122 |         dev->features = NETIF_F_NETNS_LOCAL;
      |                         ^~~~~~~~~~~~~~~~~~~
/home/fedora/nat46/nat46/modules/nat46-netdev.c:122:25: note: each undeclared identifier is reported only once for each function it appears in
make[3]: *** [scripts/Makefile.build:229: /home/fedora/nat46/nat46/modules/nat46-netdev.o] Error 1
make[2]: *** [/usr/src/kernels/6.12.11-200.fc41.x86_64/Makefile:1977: /home/fedora/nat46/nat46/modules] Error 2
make[1]: *** [Makefile:236: __sub-make] Error 2
make[1]: Leaving directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'
make: *** [Makefile:8: all] Error 2

[angus19]

Please do an extra patch to see if we are good. Thanks.

diff --git a/nat46/modules/nat46-netdev.c b/nat46/modules/nat46-netdev.c
index 75bdda2..aef959b 100644
--- a/nat46/modules/nat46-netdev.c
+++ b/nat46/modules/nat46-netdev.c
@@ -17,7 +17,6 @@
 
 
 #include <linux/if_arp.h>
-#include <linux/netdev_features.h>
 #include <linux/netdevice.h>
 #include <linux/route.h>
 #include <linux/skbuff.h>
@@ -119,7 +118,11 @@ static void nat46_netdev_setup(struct net_device *dev)
	dev->hard_header_len = 0;
	dev->addr_len = 0;
	dev->mtu = 16384; /* iptables does reassembly. Rather than using ETH_DATA_LEN, let's try to get as much mileage as we can with the Linux stack */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(6,12,0)
	dev->features = NETIF_F_NETNS_LOCAL;
+#else
+	dev->netns_local = true;
+#endif
	dev->flags = IFF_NOARP | IFF_POINTOPOINT;
 }
 

[toreanderson]

That makes it build, but with a warning:

[fedora@fedora-41 modules]$ make
make -C /lib/modules/6.12.11-200.fc41.x86_64/build M=/home/fedora/nat46/nat46/modules modules
make[1]: Entering directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-netdev.o
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-module.o
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-core.o
/home/fedora/nat46/nat46/modules/nat46-core.c:32:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration]
   32 | void static
      | ^~~~
  CC [M]  /home/fedora/nat46/nat46/modules/nat46-glue.o
  LD [M]  /home/fedora/nat46/nat46/modules/nat46.o
  MODPOST /home/fedora/nat46/nat46/modules/Module.symvers
  CC [M]  /home/fedora/nat46/nat46/modules/nat46.mod.o
  CC [M]  /home/fedora/nat46/nat46/modules/.module-common.o
  LD [M]  /home/fedora/nat46/nat46/modules/nat46.ko
  BTF [M] /home/fedora/nat46/nat46/modules/nat46.ko
Skipping BTF generation for /home/fedora/nat46/nat46/modules/nat46.ko due to unavailability of vmlinux
make[1]: Leaving directory '/usr/src/kernels/6.12.11-200.fc41.x86_64'

[angus19]

This time it is a typo. Let me fix that. Will create a new PR for fixing all errors/warnings.