[dpdk-dev] [PATCH v4 3/6] kni: set default carrier state of interface

[Dan Gora <dg@adax.com>]

Add module parameter 'carrier='on|off' to set the default carrier state
for linux network interfaces created by the KNI module.  The default
carrier state is 'off'.

For KNI interfaces which need to reflect the carrier state of
a physical Ethernet port controlled by the DPDK application, the
default carrier state should be left set to 'off'.  The application
can set the carrier state of the KNI interface to reflect the state
of the physical Ethernet port using rte_kni_update_link().

For KNI interfaces which are purely virtual, the default carrier
state can be set to 'on'.  This enables the KNI interface to be
used without having to explicity set the carrier state to 'on'
using rte_kni_update_link().

Signed-off-by: Dan Gora <dg@adax.com>
---
 kernel/linux/kni/kni_dev.h  |  3 +++
 kernel/linux/kni/kni_misc.c | 40 +++++++++++++++++++++++++++++++++++++
 kernel/linux/kni/kni_net.c  |  5 +++++
 3 files changed, 48 insertions(+)

diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h
index 6275ef27f..688f574a4 100644
--- a/kernel/linux/kni/kni_dev.h
+++ b/kernel/linux/kni/kni_dev.h
@@ -29,6 +29,9 @@
 
 #define MBUF_BURST_SZ 32
 
+/* Default carrier state for created KNI network interfaces */
+extern uint32_t dflt_carrier;
+
 /**
  * A structure describing the private information for a kni device.
  */
diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
index fa69f8e63..a5e7af2a6 100644
--- a/kernel/linux/kni/kni_misc.c
+++ b/kernel/linux/kni/kni_misc.c
@@ -39,6 +39,10 @@ static char *lo_mode;
 static char *kthread_mode;
 static uint32_t multiple_kthread_on;
 
+/* Default carrier state for created KNI network interfaces */
+static char *carrier;
+uint32_t dflt_carrier;
+
 #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
 
 static int kni_net_id;
@@ -466,6 +470,8 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 		return -ENODEV;
 	}
 
+	netif_carrier_off(net_dev);
+
 	ret = kni_run_thread(knet, kni, dev_info.force_bind);
 	if (ret != 0)
 		return ret;
@@ -590,6 +596,22 @@ kni_parse_kthread_mode(void)
 	return 0;
 }
 
+static int __init
+kni_parse_carrier_state(void)
+{
+	if (!carrier)
+		dflt_carrier = 0;
+
+	if (strcmp(carrier, "off") == 0)
+		dflt_carrier = 0;
+	else if (strcmp(carrier, "on") == 0)
+		dflt_carrier = 1;
+	else
+		return -1;
+
+	return 0;
+}
+
 static int __init
 kni_init(void)
 {
@@ -605,6 +627,16 @@ kni_init(void)
 	else
 		pr_debug("Multiple kernel thread mode enabled\n");
 
+	if (kni_parse_carrier_state() < 0) {
+		pr_err("Invalid parameter for carrier\n");
+		return -EINVAL;
+	}
+
+	if (dflt_carrier == 0)
+		pr_debug("Default carrier state set to off.\n");
+	else
+		pr_debug("Default carrier state set to on.\n");
+
 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 	rc = register_pernet_subsys(&kni_net_ops);
 #else
@@ -663,3 +695,11 @@ MODULE_PARM_DESC(kthread_mode,
 "    multiple  Multiple kernel thread mode enabled.\n"
 "\n"
 );
+
+module_param(carrier, charp, S_IRUGO);
+MODULE_PARM_DESC(carrier,
+"Defaul carrier state for KNI interface (default=off):\n"
+"    off   Interfaces will be created with carrier state set to off.\n"
+"    on    Interfaces will be created with carrier state set to on.\n"
+"\n"
+);
diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index 3a542d737..7371b6d58 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -133,6 +133,10 @@ kni_net_open(struct net_device *dev)
 	struct kni_dev *kni = netdev_priv(dev);
 
 	netif_start_queue(dev);
+	if (dflt_carrier == 1)
+		netif_carrier_on(dev);
+	else
+		netif_carrier_off(dev);
 
 	memset(&req, 0, sizeof(req));
 	req.req_id = RTE_KNI_REQ_CFG_NETWORK_IF;
@@ -152,6 +156,7 @@ kni_net_release(struct net_device *dev)
 	struct kni_dev *kni = netdev_priv(dev);
 
 	netif_stop_queue(dev); /* can't transmit any more */
+	netif_carrier_off(dev);
 
 	memset(&req, 0, sizeof(req));
 	req.req_id = RTE_KNI_REQ_CFG_NETWORK_IF;
-- 
2.19.0