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authorTomas Hozza <thozza@redhat.com>2019-08-01 12:19:34 +0200
committerTomas Hozza <thozza@redhat.com>2019-08-05 09:24:29 +0200
commit2d48474e03798c6bf5281301fa818b94a0b5597d (patch)
treef76b7d0c4944dfca4ea60219075a2b7fcbbf5c52 /lib/prefix.c
parentMerge pull request #4755 from donaldsharp/ospf_router_id_doc (diff)
downloadfrr-2d48474e03798c6bf5281301fa818b94a0b5597d.tar.xz
frr-2d48474e03798c6bf5281301fa818b94a0b5597d.zip
lib/prefix.c: ipv4_broadcast_addr() didn't comply with RFC3021
The function ipv4_broadcast_addr() does not calculate correct broadcast addresses for point-to-point connections with prefix 31. RFC3021 section 3.3 [1] specifies: "The 255.255.255.255 IP broadcast address MUST be used for broadcast Address Mask Replies in point-to-point links with 31-bit subnet masks" The issue causes Zebra to print the following warning when IPv4 address with 31 prefix (e.g. 192.168.222.240/31) is configured on a network interface: ZEBRA: [EC 4043309141] warning: interface VNS broadcast addr 255.255.255.255/31 != calculated 192.168.222.241, routing protocols may malfunction The issue has been originally found in Quagga [2], but it is present also in FRR. [1] https://tools.ietf.org/html/rfc3021#section-3.3 [2] https://bugzilla.redhat.com/show_bug.cgi?id=1713449 Signed-off-by: Tomas Hozza <thozza@redhat.com>
Diffstat (limited to 'lib/prefix.c')
-rw-r--r--lib/prefix.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/lib/prefix.c b/lib/prefix.c
index 1a4a914e0..85bbb18f3 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -1468,11 +1468,11 @@ in_addr_t ipv4_broadcast_addr(in_addr_t hostaddr, int masklen)
masklen2ip(masklen, &mask);
return (masklen != IPV4_MAX_PREFIXLEN - 1) ?
- /* normal case */
- (hostaddr | ~mask.s_addr)
- :
- /* special case for /31 */
- (hostaddr ^ ~mask.s_addr);
+ /* normal case */
+ (hostaddr | ~mask.s_addr)
+ :
+ /* For prefix 31 return 255.255.255.255 (RFC3021) */
+ htonl(0xFFFFFFFF);
}
/* Utility function to convert ipv4 netmask to prefixes