[rtsock] Enforce netmask/RTF_HOST consistency.

Traditionally we had 2 sources of information whether the
 added/delete route request targets network or a host route:
netmask (RTA_NETMASK) and RTF_HOST flag.

The former one is tricky: netmask can be empty or can explicitly
 specify the host netmask. Parsing netmask sockaddr requires per-family
 parsing and that's what rtsock code traditionally avoided. As a result,
 consistency was not enforced and it was possible to specify network with
 the RTF_HOST flag and vice versa.

Continue normalization efforts from D29826 and D29826 and ensure that
 RTF_HOST flag always reflects host/network data from netmask field.

Differential Revision: https://reviews.freebsd.org/D29958
MFC after:	2 days

(cherry picked from commit 5d1403a79a3e56403fb63c062252a23fce81e5f1)

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 405300a394de..6930bd167ac1 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1503,6 +1503,7 @@ cleanup_xaddrs_inet(struct rt_addrinfo *info, struct linear_buffer *lb)
 			return (ENOBUFS);
 		fill_sockaddr_inet(mask_sa, mask);
 		info->rti_info[RTAX_NETMASK] = (struct sockaddr *)mask_sa;
+		info->rti_flags &= ~RTF_HOST;
 	} else
 		remove_netmask(info);
 
@@ -1563,6 +1564,7 @@ cleanup_xaddrs_inet6(struct rt_addrinfo *info, struct linear_buffer *lb)
 			return (ENOBUFS);
 		fill_sockaddr_inet6((struct sockaddr_in6 *)sa, &mask, 0);
 		info->rti_info[RTAX_NETMASK] = sa;
+		info->rti_flags &= ~RTF_HOST;
 	} else
 		remove_netmask(info);