odhcpd: detect broken hostnames

Check hostnames contain valid characters as defined in RFC 952 and RFC 1123.
Invalid hostnames in uci configured host entries will result into a refusal
to create the static lease.
In case a client received hostname contains an invalid character no
<hostname> <IP address> entry will be added to the lease file.
In such case the leaseinfo description in the lease file will still contain
the hostname but preceded by the string broken\x20

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/ubus.c b/src/ubus.c
index 5be6bbe..1aec590 100644
--- a/src/ubus.c
+++ b/src/ubus.c
@@ -53,6 +53,9 @@ static int handle_dhcpv4_leases(struct ubus_context *ctx, _unused struct ubus_ob
 
 			if (c->flags & OAF_STATIC)
 				blobmsg_add_string(&b, NULL, "static");
+
+			if (c->flags & OAF_BROKEN_HOSTNAME)
+				blobmsg_add_string(&b, NULL, "broken-hostname");
 			blobmsg_close_array(&b, m);
 
 			buf = blobmsg_alloc_string_buffer(&b, "address", INET_ADDRSTRLEN);