treewide: remove obsolete kernel version checks

We don't support Linux kernels older than 4.4 in Nixpkgs.

nixos/modules/hardware/network/b43.nix

@@ -24,10 +24,6 @@ let kernelVersion = config.boot.kernelPackages.kernel.version; in
   ###### implementation
 
   config = mkIf config.networking.enableB43Firmware {
-    assertions = singleton
-      { assertion = lessThan 0 (builtins.compareVersions kernelVersion "3.2");
-        message = "b43 firmware for kernels older than 3.2 not packaged yet!";
-      };
     hardware.firmware = [ pkgs.b43Firmware_5_1_138 ];
   };
 

nixos/modules/hardware/video/capture/mwprocapture.nix

@@ -16,11 +16,6 @@ in
 
   config = mkIf cfg.enable {
 
-    assertions = singleton {
-      assertion = versionAtLeast kernelPackages.kernel.version "3.2";
-      message = "Magewell Pro Capture family module is not supported for kernels older than 3.2";
-    };
-
     boot.kernelModules = [ "ProCapture" ];
 
     environment.systemPackages = [ kernelPackages.mwprocapture ];

nixos/modules/security/wrappers/default.nix

@@ -92,7 +92,6 @@ let
     , permissions
     , ...
     }:
-    assert (lib.versionAtLeast (lib.getVersion config.boot.kernelPackages.kernel) "4.3");
     ''
       cp ${securityWrapper}/bin/security-wrapper "$wrapperDir/${program}"
       echo -n "${source}" > "$wrapperDir/${program}.real"

nixos/modules/services/networking/firewall.nix

@@ -433,8 +433,6 @@ in
             drop the packet if the source address is not reachable via any
             interface) or false.  Defaults to the value of
             kernelHasRPFilter.
-
-            (needs kernel 3.3+)
           '';
       };
 

nixos/modules/services/networking/multipath.nix

@@ -242,21 +242,6 @@ in {
             '';
           };
 
-          retain_attached_hw_handler = mkOption {
-            type = nullOr (enum [ "yes" "no" ]);
-            default = null; # real default: "yes"
-            description = ''
-              (Obsolete for kernels >= 4.3) If set to "yes" and the SCSI layer has
-              already attached a hardware_handler to the device, multipath will not
-              force the device to use the hardware_handler specified by mutipath.conf.
-              If the SCSI layer has not attached a hardware handler, multipath will
-              continue to use its configured hardware handler.
-
-              Important Note: Linux kernel 4.3 or newer always behaves as if
-              "retain_attached_hw_handler yes" was set.
-            '';
-          };
-
           detect_prio = mkOption {
             type = nullOr (enum [ "yes" "no" ]);
             default = null; # real default: "yes"

nixos/modules/tasks/network-interfaces.nix

@@ -1325,22 +1325,13 @@ in
           val = tempaddrValues.${opt}.sysctl;
          in nameValuePair "net.ipv6.conf.${replaceChars ["."] ["/"] i.name}.use_tempaddr" val));
 
-    # Capabilities won't work unless we have at-least a 4.3 Linux
-    # kernel because we need the ambient capability
-    security.wrappers = if (versionAtLeast (getVersion config.boot.kernelPackages.kernel) "4.3") then {
+    security.wrappers = {
       ping = {
         owner = "root";
         group = "root";
         capabilities = "cap_net_raw+p";
         source = "${pkgs.iputils.out}/bin/ping";
       };
-    } else {
-      ping = {
-        setuid = true;
-        owner = "root";
-        group = "root";
-        source = "${pkgs.iputils.out}/bin/ping";
-      };
     };
     security.apparmor.policies."bin.ping".profile = lib.mkIf config.security.apparmor.policies."bin.ping".enable (lib.mkAfter ''
       /run/wrappers/bin/ping {

pkgs/os-specific/linux/mwprocapture/default.nix

@@ -60,6 +60,5 @@ stdenv.mkDerivation rec {
     license = licenses.unfreeRedistributable;
     maintainers = with maintainers; [ MP2E ];
     platforms = platforms.linux;
-    broken = kernel.kernelOlder "3.2.0";
   };
 }