From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 2 Dec 2020 10:19:06 +0000 (+0900)
Subject: network: do not set broadcast if prefixlen is 31 or 32
X-Git-Tag: v247.2~35
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=dc6ad6482a492a9aa04cd05181d6e3ab0d34b66a;p=thirdparty%2Fsystemd.git

network: do not set broadcast if prefixlen is 31 or 32

After fe841414ef157f7f01d339c5d5730126e7b5fe0a, broadcast address is
also compared with existing one to determine whether the address is
foregin or not. So, the address object should not contain unnecessary
information.

Fixes #17803.

(cherry picked from commit df8aa086420e6ce61e32898b2bb7c88b87fd1c43)
---

diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index 02d33841b69..68d975924c9 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -861,7 +861,8 @@ static int dhcp4_update_address(Link *link, bool announce) {
         addr->cinfo.ifa_prefered = lifetime;
         addr->cinfo.ifa_valid = lifetime;
         addr->prefixlen = prefixlen;
-        addr->broadcast.s_addr = address.s_addr | ~netmask.s_addr;
+        if (prefixlen <= 30)
+                addr->broadcast.s_addr = address.s_addr | ~netmask.s_addr;
         SET_FLAG(addr->flags, IFA_F_NOPREFIXROUTE, !link_prefixroute(link));
 
         /* allow reusing an existing address and simply update its lifetime