build: check for sendmmsg() and struct mmsghdr

These will be used by the RFC5424 log target.

Signed-off-by: David Lamparter <equinox@diac24.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/zebra.h b/lib/zebra.h
index 139e47e8d7..e8ddd869bb 100644
--- a/lib/zebra.h
+++ b/lib/zebra.h
@@ -230,6 +230,26 @@ size_t strlcpy(char *__restrict dest,
 	       const char *__restrict src, size_t destsize);
 #endif
 
+#if !defined(HAVE_STRUCT_MMSGHDR_MSG_HDR) || !defined(HAVE_SENDMMSG)
+/* avoid conflicts in case we have partial support */
+#define mmsghdr frr_mmsghdr
+#define sendmmsg frr_sendmmsg
+
+struct mmsghdr {
+	struct msghdr msg_hdr;
+	unsigned int msg_len;
+};
+
+/* just go 1 at a time here, the loop this is used in will handle the rest */
+static inline int sendmmsg(int fd, struct mmsghdr *mmh, unsigned int len,
+			   int flags)
+{
+	int rv = sendmsg(fd, &mmh->msg_hdr, 0);
+
+	return rv > 0 ? 1 : rv;
+}
+#endif
+
 /*
  * RFC 3542 defines several macros for using struct cmsghdr.
  * Here, we define those that are not present