net: rmnet_data: In-band flow control

Implement MAP based in-band flow control. Added 2 new configuration
messages to allow adding and deleting flow handles. Added handlers
in VND for flow control events. Added flow control command handler
in rmnet_map_commands.

CRs-fixed: 568534
Change-Id: Ica52e4ad89430c9fa5e2b38e389ee6bc91de2e9b
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>

1 files changed, 91 insertions, 3 deletions

diff --git a/net/rmnet_data/rmnet_map_command.c b/net/rmnet_data/rmnet_map_command.c
index 68acf2d9561a..a3a5bfc705dd 100644
--- a/net/rmnet_data/rmnet_map_command.c
+++ b/net/rmnet_data/rmnet_map_command.c
@@ -20,18 +20,95 @@
 #include "rmnet_data_config.h"
 #include "rmnet_map.h"
 #include "rmnet_data_private.h"
+#include "rmnet_data_vnd.h"
+
+RMNET_LOG_MODULE(RMNET_DATA_LOGMASK_MAPC);
 
 unsigned long int rmnet_map_command_stats[RMNET_MAP_COMMAND_ENUM_LENGTH];
 module_param_array(rmnet_map_command_stats, ulong, 0, S_IRUGO);
 MODULE_PARM_DESC(rmnet_map_command_stats, "MAP command statistics");
 
+/**
+ * rmnet_map_do_flow_control() - Process MAP flow control command
+ * @skb: Socket buffer containing the MAP flow control message
+ * @config: Physical end-point configuration of ingress device
+ * @enable: boolean for enable/disable
+ *
+ * Process in-band MAP flow control messages. Assumes mux ID is mapped to a
+ * RmNet Data vitrual network device.
+ *
+ * Return:
+ *      - RMNET_MAP_COMMAND_UNSUPPORTED on any error
+ *      - RMNET_MAP_COMMAND_ACK on success
+ */
 static uint8_t rmnet_map_do_flow_control(struct sk_buff *skb,
 					 struct rmnet_phys_ep_conf_s *config,
 					 int enable)
 {
-	return RMNET_MAP_COMMAND_UNSUPPORTED;
+	struct rmnet_map_control_command_s *cmd;
+	struct net_device *vnd;
+	struct rmnet_logical_ep_conf_s *ep;
+	uint8_t mux_id;
+	uint16_t  ip_family;
+	uint16_t  fc_seq;
+	uint32_t  qos_id;
+	int r;
+
+	if (unlikely(!skb || !config))
+		BUG();
+
+	mux_id = RMNET_MAP_GET_MUX_ID(skb);
+	cmd = RMNET_MAP_GET_CMD_START(skb);
+
+	if (mux_id >= RMNET_DATA_MAX_LOGICAL_EP) {
+		LOGD("%s(): Got packet on %s with bad mux id %d\n",
+				__func__, skb->dev->name, mux_id);
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
+	ep = &(config->muxed_ep[mux_id]);
+
+	if (!ep->refcount) {
+		LOGD("%s(): Packet on %s:%d; has no logical endpoint config\n",
+		     __func__, skb->dev->name, mux_id);
+
+		kfree_skb(skb);
+			return RX_HANDLER_CONSUMED;
+	}
+
+	vnd = ep->egress_dev;
+
+	ip_family = cmd->flow_control.ip_family;
+	fc_seq = ntohs(cmd->flow_control.flow_control_seq_num);
+	qos_id = ntohl(cmd->flow_control.qos_id);
+
+	/* Ignore the ip family and pass the sequence number for both v4 and v6
+	 * sequence. User space does not support creating dedicated flows for
+	 * the 2 protocols
+	 */
+	r = rmnet_vnd_do_flow_control(vnd, qos_id, fc_seq, fc_seq, enable);
+	LOGD("%s(): dev:%s, qos_id:0x%08X, ip_family:%hd, fc_seq %hd, en:%d\n",
+	     __func__, skb->dev->name, qos_id, ip_family & 3, fc_seq, enable);
+
+	if (r)
+		return RMNET_MAP_COMMAND_UNSUPPORTED;
+	else
+		return RMNET_MAP_COMMAND_ACK;
 }
 
+/**
+ * rmnet_map_send_ack() - Send N/ACK message for MAP commands
+ * @skb: Socket buffer containing the MAP command message
+ * @type: N/ACK message selector
+ *
+ * skb is modified to contain the message type selector. The message is then
+ * transmitted on skb->dev. Note that this function grabs global Tx lock on
+ * skb->dev for latency reasons.
+ *
+ * Return:
+ *      - void
+ */
 static void rmnet_map_send_ack(struct sk_buff *skb,
 			       unsigned char type)
 {
@@ -53,6 +130,17 @@ static void rmnet_map_send_ack(struct sk_buff *skb,
 	spin_unlock_irqrestore(&(skb->dev->tx_global_lock), flags);
 }
 
+/**
+ * rmnet_map_command() - Entry point for handling MAP commands
+ * @skb: Socket buffer containing the MAP command message
+ * @config: Physical end-point configuration of ingress device
+ *
+ * Process MAP command frame and send N/ACK message as appropriate. Message cmd
+ * name is decoded here and appropriate handler is called.
+ *
+ * Return:
+ *      - RX_HANDLER_CONSUMED. Command frames are always consumed.
+ */
 rx_handler_result_t rmnet_map_command(struct sk_buff *skb,
 				      struct rmnet_phys_ep_conf_s *config)
 {
@@ -60,7 +148,7 @@ rx_handler_result_t rmnet_map_command(struct sk_buff *skb,
 	unsigned char command_name;
 	unsigned char rc = 0;
 
-	if (!skb)
+	if (unlikely(!skb))
 		BUG();
 
 	cmd = RMNET_MAP_GET_CMD_START(skb);
@@ -85,5 +173,5 @@ rx_handler_result_t rmnet_map_command(struct sk_buff *skb,
 		break;
 	}
 	rmnet_map_send_ack(skb, rc);
-	return 0; /* TODO: handler_consumed */
+	return RX_HANDLER_CONSUMED;
 }