tipc: add bearer disable/enable to new netlink api

A new netlink API for tipc that can disable or enable a tipc bearer.

The new API is separated from the old API because of a bug in the
user space client (tipc-config). The problem is that older versions
of tipc-config has a very low receive limit and adding commands to
the legacy genl_opts struct causes the ctrl_getfamily() response
message to grow, subsequently breaking the tool.

The new API utilizes netlink policies for input validation. Where the
top-level netlink attributes are tipc-logical entities, like bearer.
The top level entities then contain nested attributes. In this case
a name, nested link properties and a domain.

Netlink commands implemented in this patch:
TIPC_NL_BEARER_ENABLE
TIPC_NL_BEARER_DISABLE

Netlink logical layout of bearer enable message:
-> bearer
    -> name
    [ -> domain ]
    [
    -> properties
        -> priority
    ]

Netlink logical layout of bearer disable message:
-> bearer
    -> name

Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 0 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 7cf8004577f1..e7f365012bd1 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -40,6 +40,7 @@
 #include "name_distr.h"
 #include "discover.h"
 #include "config.h"
+#include "netlink.h"
 
 #include <linux/pkt_sched.h>
 
@@ -50,6 +51,14 @@ static const char *link_co_err = "Link changeover error, ";
 static const char *link_rst_msg = "Resetting link ";
 static const char *link_unk_evt = "Unknown link event ";
 
+/* Properties valid for media, bearar and link */
+static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
+	[TIPC_NLA_PROP_UNSPEC]		= { .type = NLA_UNSPEC },
+	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
+	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
+	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 }
+};
+
 /*
  * Out-of-range value for link session numbers
  */
@@ -2376,3 +2385,41 @@ static void link_print(struct tipc_link *l_ptr, const char *str)
 	else
 		pr_cont("\n");
 }
+
+/* Parse and validate nested (link) properties valid for media, bearer and link
+ */
+int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
+{
+	int err;
+
+	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
+			       tipc_nl_prop_policy);
+	if (err)
+		return err;
+
+	if (props[TIPC_NLA_PROP_PRIO]) {
+		u32 prio;
+
+		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
+		if (prio > TIPC_MAX_LINK_PRI)
+			return -EINVAL;
+	}
+
+	if (props[TIPC_NLA_PROP_TOL]) {
+		u32 tol;
+
+		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
+		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
+			return -EINVAL;
+	}
+
+	if (props[TIPC_NLA_PROP_WIN]) {
+		u32 win;
+
+		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
+		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
+			return -EINVAL;
+	}
+
+	return 0;
+}