netlink-socket.c: add support for do_lookup_genl_family on Windows

In this patch, we add support for querying the genl family id for any
family supported by the OVS kernel datapath. On platforms that support
netlink natively, the operating system assigns a family ID, and the
OS netlink infrastructure supports querying the family ID by name.

In case of Windows, since OVS datpath provides the netlink support,
it is not necessary to make a call into the kernel. Returning a
family ID that is consistent between the userspace and kernel
is sufficient. Once there is code to support netlink message parsing
as well as constructing netlink messages, we can make a call into
the kernel, but that in itself may not buy anything more than this
approach.

This patch is a precursor to make progress of the other commands.
The next hurdle is to support nl_lookup_genl_mcgroup().

Signed-off-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c
index 3f1a712..98baf58 100644 (file)
--- a/lib/netlink-socket.c
+++ b/lib/netlink-socket.c
@@ -1128,6 +1128,7 @@ genl_family_to_name(uint16_t id)
     }
 }
 
+#ifndef _WIN32
 static int
 do_lookup_genl_family(const char *name, struct nlattr **attrs,
                       struct ofpbuf **replyp)
@@ -1165,6 +1166,73 @@ do_lookup_genl_family(const char *name, struct nlattr **attrs,
     *replyp = reply;
     return 0;
 }
+#else
+static int
+do_lookup_genl_family(const char *name, struct nlattr **attrs,
+                      struct ofpbuf **replyp)
+{
+    struct nl_sock *sock;
+    struct ofpbuf *reply;
+    int error;
+    uint16_t family_id;
+    const char *family_name;
+    uint32_t family_version;
+    uint32_t family_attrmax;
+
+    *replyp = NULL;
+    reply = ofpbuf_new(1024);
+
+    if (!strcmp(name, OVS_WIN_CONTROL_FAMILY)) {
+        family_id = OVS_WIN_NL_CTRL_FAMILY_ID;
+        family_name = OVS_WIN_CONTROL_FAMILY;
+        family_version = OVS_WIN_CONTROL_VERSION;
+        family_attrmax = OVS_WIN_CONTROL_ATTR_MAX;
+    } else if (!strcmp(name, OVS_DATAPATH_FAMILY)) {
+        family_id = OVS_WIN_NL_DATAPATH_FAMILY_ID;
+        family_name = OVS_DATAPATH_FAMILY;
+        family_version = OVS_DATAPATH_VERSION;
+        family_attrmax = OVS_DP_ATTR_MAX;
+    } else if (!strcmp(name, OVS_PACKET_FAMILY)) {
+        family_id = OVS_WIN_NL_PACKET_FAMILY_ID;
+        family_name = OVS_PACKET_FAMILY;
+        family_version = OVS_PACKET_VERSION;
+        family_attrmax = OVS_PACKET_ATTR_MAX;
+    } else if (!strcmp(name, OVS_VPORT_FAMILY)) {
+        family_id = OVS_WIN_NL_VPORT_FAMILY_ID;
+        family_name = OVS_VPORT_FAMILY;
+        family_version = OVS_VPORT_VERSION;
+        family_attrmax = OVS_VPORT_ATTR_MAX;
+    } else if (!strcmp(name, OVS_FLOW_FAMILY)) {
+        family_id = OVS_WIN_NL_FLOW_FAMILY_ID;
+        family_name = OVS_FLOW_FAMILY;
+        family_version = OVS_FLOW_VERSION;
+        family_attrmax = OVS_FLOW_ATTR_MAX;
+    } else {
+        ofpbuf_delete(reply);
+        return EINVAL;
+    }
+
+    nl_msg_put_genlmsghdr(reply, 0, GENL_ID_CTRL, 0,
+                          CTRL_CMD_NEWFAMILY, family_version);
+    /* CTRL_ATTR_HDRSIZE and CTRL_ATTR_OPS are not populated, but the
+     * callers do not seem to need them. */
+    nl_msg_put_u16(reply, CTRL_ATTR_FAMILY_ID, family_id);
+    nl_msg_put_string(reply, CTRL_ATTR_FAMILY_NAME, family_name);
+    nl_msg_put_u32(reply, CTRL_ATTR_VERSION, family_version);
+    nl_msg_put_u32(reply, CTRL_ATTR_MAXATTR, family_attrmax);
+
+    if (!nl_policy_parse(reply, NLMSG_HDRLEN + GENL_HDRLEN,
+                         family_policy, attrs, ARRAY_SIZE(family_policy))
+        || nl_attr_get_u16(attrs[CTRL_ATTR_FAMILY_ID]) == 0) {
+        nl_sock_destroy(sock);
+        ofpbuf_delete(reply);
+        return EPROTO;
+    }
+
+    *replyp = reply;
+    return 0;
+}
+#endif
 
 /* Finds the multicast group called 'group_name' in genl family 'family_name'.
  * When successful, writes its result to 'multicast_group' and returns 0.