2005-01-04 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* configure.ac: Added test for broken CMSG_FIRSTHDR macro
	  (relevant for Solaris 8 and unpatched Solaris 9, don't know
	  whether other platforms are affected).
	* zebra.h: Define ZCMSG_FIRSTHDR appropriately based on whether
	  config.h indicates HAVE_BROKEN_CMSG_FIRSTHDR (as determined
	  by the configure test program).
	* sockopt.c: (getsockopt_cmsg_data) Use ZCMSG_FIRSTHDR instead
	  of CMSG_FIRSTHDR.
	* rtadv.c: (rtadv_recv_packet,rtadv_send_packet) Use ZCMSG_FIRSTHDR
	  instead of CMSG_FIRSTHDR.
	* ripd.c: (rip_recvmsg) Use ZCMSG_FIRSTHDR instead of CMSG_FIRSTHDR.
	* ripngd.c: (ripng_recv_packet) Use ZCMSG_FIRSTHDR instead of
	  CMSG_FIRSTHDR.
diff --git a/lib/zebra.h b/lib/zebra.h
index 83da37c..8c2dcab 100644
--- a/lib/zebra.h
+++ b/lib/zebra.h
@@ -215,6 +215,23 @@
 
 #endif /* BSDI_NRL */
 
+#ifdef HAVE_BROKEN_CMSG_FIRSTHDR
+/* This bug is present in Solaris 8 and pre-patch Solaris 9 <sys/socket.h>;
+   please refer to http://bugzilla.quagga.net/show_bug.cgi?id=142 */
+
+/* Check that msg_controllen is large enough. */
+#define ZCMSG_FIRSTHDR(mhdr) \
+  (((size_t)((mhdr)->msg_controllen) >= sizeof(struct cmsghdr)) ? \
+   CMSG_FIRSTHDR(mhdr) : (struct cmsghdr *)NULL)
+
+#warning "CMSG_FIRSTHDR is broken on this platform, using a workaround"
+
+#else /* HAVE_BROKEN_CMSG_FIRSTHDR */
+#define ZCMSG_FIRSTHDR(M) CMSG_FIRSTHDR(M)
+#endif /* HAVE_BROKEN_CMSG_FIRSTHDR */
+
+
+
 /* 
  * RFC 3542 defines several macros for using struct cmsghdr.
  * Here, we define those that are not present