svn commit: r226402 - head/sys/netinet
Gleb Smirnoff
glebius at FreeBSD.org
Sat Oct 15 18:41:26 UTC 2011
Author: glebius
Date: Sat Oct 15 18:41:25 2011
New Revision: 226402
URL: http://svn.freebsd.org/changeset/base/226402
Log:
Add support for IPv4 /31 prefixes, as described in RFC3021.
To run a /31 network, participating hosts MUST drop support
for directed broadcasts, and treat the first and last addresses
on subnet as unicast. The broadcast address for the prefix
should be the link local broadcast address, INADDR_BROADCAST.
Modified:
head/sys/netinet/in.c
head/sys/netinet/in.h
Modified: head/sys/netinet/in.c
==============================================================================
--- head/sys/netinet/in.c Sat Oct 15 16:28:06 2011 (r226401)
+++ head/sys/netinet/in.c Sat Oct 15 18:41:25 2011 (r226402)
@@ -897,8 +897,11 @@ in_ifinit(struct ifnet *ifp, struct in_i
*/
ia->ia_ifa.ifa_metric = ifp->if_metric;
if (ifp->if_flags & IFF_BROADCAST) {
- ia->ia_broadaddr.sin_addr.s_addr =
- htonl(ia->ia_subnet | ~ia->ia_subnetmask);
+ if (ia->ia_subnetmask == IN_RFC3021_MASK)
+ ia->ia_broadaddr.sin_addr.s_addr = INADDR_BROADCAST;
+ else
+ ia->ia_broadaddr.sin_addr.s_addr =
+ htonl(ia->ia_subnet | ~ia->ia_subnetmask);
} else if (ifp->if_flags & IFF_LOOPBACK) {
ia->ia_dstaddr = ia->ia_addr;
flags |= RTF_HOST;
@@ -1230,9 +1233,11 @@ in_broadcast(struct in_addr in, struct i
if (ifa->ifa_addr->sa_family == AF_INET &&
(in.s_addr == ia->ia_broadaddr.sin_addr.s_addr ||
/*
- * Check for old-style (host 0) broadcast.
+ * Check for old-style (host 0) broadcast, but
+ * taking into account that RFC 3021 obsoletes it.
*/
- t == ia->ia_subnet) &&
+ (ia->ia_subnetmask != IN_RFC3021_MASK &&
+ t == ia->ia_subnet)) &&
/*
* Check for an all one subnetmask. These
* only exist when an interface gets a secondary
Modified: head/sys/netinet/in.h
==============================================================================
--- head/sys/netinet/in.h Sat Oct 15 16:28:06 2011 (r226401)
+++ head/sys/netinet/in.h Sat Oct 15 18:41:25 2011 (r226402)
@@ -392,6 +392,8 @@ __END_DECLS
#define IN_LOOPBACKNET 127 /* official! */
+#define IN_RFC3021_MASK (u_int32_t)0xfffffffe
+
/*
* Options for use with [gs]etsockopt at the IP level.
* First word of comment is data type; bool is stored in int.
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