drop_monitor: Add a command to query current configuration

Users should be able to query the current configuration of drop monitor
before they start using it. Add a command to query the existing
configuration which currently consists of alert mode and packet
truncation length.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h
index 5cd7eb1..3b765a8 100644 (file)
--- a/include/uapi/linux/net_dropmon.h
+++ b/include/uapi/linux/net_dropmon.h
@@ -54,6 +54,8 @@ enum {
        NET_DM_CMD_START,
        NET_DM_CMD_STOP,
        NET_DM_CMD_PACKET_ALERT,
+       NET_DM_CMD_CONFIG_GET,
+       NET_DM_CMD_CONFIG_NEW,
        _NET_DM_CMD_MAX,
 };
 

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 9f884ad..1356384 100644 (file)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -676,6 +676,50 @@ static int net_dm_cmd_trace(struct sk_buff *skb,
        return -EOPNOTSUPP;
 }
 
+static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
+{
+       void *hdr;
+
+       hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+                         &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
+       if (!hdr)
+               return -EMSGSIZE;
+
+       if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
+               goto nla_put_failure;
+
+       if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
+               goto nla_put_failure;
+
+       genlmsg_end(msg, hdr);
+
+       return 0;
+
+nla_put_failure:
+       genlmsg_cancel(msg, hdr);
+       return -EMSGSIZE;
+}
+
+static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
+{
+       struct sk_buff *msg;
+       int rc;
+
+       msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       rc = net_dm_config_fill(msg, info);
+       if (rc)
+               goto free_msg;
+
+       return genlmsg_reply(msg, info);
+
+free_msg:
+       nlmsg_free(msg);
+       return rc;
+}
+
 static int dropmon_net_event(struct notifier_block *ev_block,
                             unsigned long event, void *ptr)
 {
@@ -738,6 +782,10 @@ static const struct genl_ops dropmon_ops[] = {
                .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
                .doit = net_dm_cmd_trace,
        },
+       {
+               .cmd = NET_DM_CMD_CONFIG_GET,
+               .doit = net_dm_cmd_config_get,
+       },
 };
 
 static int net_dm_nl_pre_doit(const struct genl_ops *ops,