build: don't check or include some kernel headers if inappropriate fo…

…r build

Some kernel headers are not needed if building without IPVS support, and
similarly some some kernel headers are not needed if building without VRRP
support.

In these cases, do not check for the existence of some of the headers at
configure time, and do not include the headers at compile  time.

Signed-off-by: Quentin Armitage <quentin@armitage.org.uk>

configure.ac

@@ -1142,37 +1142,49 @@ AC_LINK_IFELSE([AC_LANG_SOURCE([[
 # Checks for header files.
 AC_CHECK_HEADERS([arpa/inet.h fcntl.h limits.h netdb.h netinet/in.h stdint.h stdlib.h string.h sys/ioctl.h sys/param.h sys/prctl.h sys/socket.h sys/time.h syslog.h unistd.h],
   [], [AC_MSG_ERROR([Missing/unusable system header file <$ac_header>])])
+AS_IF([test .$enable_lvs != .no],
+  [AC_CHECK_HEADERS([net/if_arp.h],
+    [], [AC_MSG_ERROR([Missing/unusable <$ac_header> - is glibc headers package installed?])])
+  ])
 
 # check for kernel headers
 SAV_CPPFLAGS="$CPPFLAGS"
 CPPFLAGS="$CPPFLAGS $kernelinc"
 
-dnl -- linux/errqueue.h need sys/time.h before Linux < v5.1
-AC_MSG_CHECKING([linux/errqueue.h needs sys/time.h])
-AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
-  #include <fcntl.h>
-  #include <linux/errqueue.h>
-
-  int main(void)
-  {
-  }
-  ]])],
+AC_CHECK_HEADERS([linux/types.h],
+  [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header> - is kernel headers package installed?])])
+AS_IF([test .$enable_vrrp != .no],
   [
-    AC_MSG_RESULT([no])
-  ],
+    AC_CHECK_HEADERS([linux/ethtool.h linux/if_ether.h linux/if_packet.h linux/ip.h linux/sockios.h],
+      [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header> - is kernel headers package installed?])])
+    AC_CHECK_HEADERS([linux/fib_rules.h linux/if_addr.h linux/if_link.h],
+      [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header> - is kernel headers package installed?])],
+      [[$NETLINK_EXTRA_INCLUDE]])
+  ])
+AS_IF([test .$enable_lvs != .no],
   [
-    AC_MSG_RESULT([yes])
-    AC_DEFINE([ERRQUEUE_NEEDS_SYS_TIME], [ 1 ], [Define to 1 if linux/errqueue.h needs sys/time.h])
+    AC_CHECK_HEADERS([linux/icmp.h linux/icmpv6.h linux/errqueue.h],
+      [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header> - is kernel headers package installed?])])
+
+    dnl -- linux/errqueue.h need sys/time.h before Linux < v5.1
+    AC_MSG_CHECKING([linux/errqueue.h needs sys/time.h])
+    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+      #include <fcntl.h>
+      #include <linux/errqueue.h>
+
+      int main(void)
+      {
+      }
+      ]])],
+      [
+	AC_MSG_RESULT([no])
+      ],
+      [
+	AC_MSG_RESULT([yes])
+	AC_DEFINE([ERRQUEUE_NEEDS_SYS_TIME], [ 1 ], [Define to 1 if linux/errqueue.h needs sys/time.h])
+      ])
   ])
 
-AC_CHECK_HEADERS([asm/types.h linux/ethtool.h linux/icmpv6.h linux/if_ether.h linux/if_packet.h linux/ip.h linux/sockios.h linux/types.h],
-  [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header>])])
-AC_CHECK_HEADERS([linux/fib_rules.h linux/if_addr.h linux/if_link.h],
-  [], [AC_MSG_ERROR([Missing/unusable kernel header file <$ac_header>])],
-  [[$NETLINK_EXTRA_INCLUDE]])
-AC_CHECK_HEADERS([linux/if_arp.h],
-  [], [AC_MSG_ERROR([Missing/unusable <$ac_header>])],
-  [[#include <sys/socket.h>]])
 CPPFLAGS="$SAV_CPPFLAGS"
 
 # Checks for typedefs, structures, and compiler characteristics.

keepalived/core/keepalived_netlink.c

@@ -42,14 +42,12 @@
 #include <time.h>
 #ifdef _WITH_VRRP_
 #include <linux/version.h>
-#ifdef _WITH_VRRP_
 #include <linux/fib_rules.h>
-#endif
-#endif
 #include <linux/ip.h>
+#include <linux/if_link.h>
+#endif
 #include <unistd.h>
 #include <inttypes.h>
-#include <linux/if_link.h>
 
 #ifdef THREAD_DUMP
 #include "scheduler.h"

keepalived/core/layer4.c

@@ -29,12 +29,14 @@
 #include <fcntl.h>
 #include <netinet/in.h>
 #include <net/if.h>
+#ifdef _WITH_LVS_
 #include <linux/icmp.h>
 #include <linux/icmpv6.h>
 #ifdef ERRQUEUE_NEEDS_SYS_TIME
 #include <sys/time.h>
 #endif
 #include <linux/errqueue.h>
+#endif
 
 #include "layer4.h"
 #include "logger.h"