From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 13 Apr 2026 23:12:49 +0000 (+0900)
Subject: ip-util: define IPV4_MIN_REASSEMBLY_SIZE
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=3b4e01637f45dad8bf9fde6da05ad43a14a5e92b;p=thirdparty%2Fsystemd.git

ip-util: define IPV4_MIN_REASSEMBLY_SIZE

The number will be later used at several places.
---

diff --git a/src/libsystemd-network/ip-util.h b/src/libsystemd-network/ip-util.h
index fbc602ace59..31fa4631c35 100644
--- a/src/libsystemd-network/ip-util.h
+++ b/src/libsystemd-network/ip-util.h
@@ -8,6 +8,12 @@
 
 #include "sparse-endian.h"
 
+/* RFC 791
+ * Fragmentation and Reassembly.
+ * Every internet destination must be able to receive a datagram of 576 octets either in one piece or in
+ * fragments to be reassembled. */
+#define IPV4_MIN_REASSEMBLY_SIZE 576u
+
 /* This is a maximal UDP payload size in a packet when its IP header does not contain options. When a packet
  * contains some IP options, then of course the allowed UDP payload size in the packet becomes smaller. */
 #define UDP_PAYLOAD_MAX_SIZE (UINT16_MAX - sizeof(struct iphdr) - sizeof(struct udphdr))