From e77aa7b65eb0d08f63d0ea3dea68f3bbe97d75f4 Mon Sep 17 00:00:00 2001
From: Hendrik van Essen <hendrik.vanessen@ml-pa.com>
Date: Wed, 5 Oct 2022 16:28:13 +0200
Subject: [PATCH] net/ipv4/addr.h: add ipv4_addr_is_multicast

---
 sys/include/net/ipv4/addr.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/sys/include/net/ipv4/addr.h b/sys/include/net/ipv4/addr.h
index 30cc5fcb3c..73a0662d4e 100644
--- a/sys/include/net/ipv4/addr.h
+++ b/sys/include/net/ipv4/addr.h
@@ -57,6 +57,23 @@ static inline bool ipv4_addr_equal(const ipv4_addr_t *a, const ipv4_addr_t *b)
     return (a->u32.u32 == b->u32.u32);
 }
 
+/**
+ * @brief   Check if @p addr is a multicast address.
+ *
+ * @see <a href="https://www.rfc-editor.org/rfc/rfc1112.html#section-4">
+ *          RFC 1112, section 4
+ *      </a>
+ *
+ * @param[in] addr  An IPv4 address.
+ *
+ * @return  true, if @p addr is multicast address,
+ * @return  false, otherwise.
+ */
+static inline bool ipv4_addr_is_multicast(const ipv4_addr_t *addr)
+{
+    return (addr->u8[0] >= 0xE0 && addr->u8[0] <= 0xEF);
+}
+
 /**
  * @brief   Converts an IPv4 address to its string representation
  *