1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
3  */
4 
5 #include <linux/netdevice.h>
6 #include "rmnet_config.h"
7 #include "rmnet_map.h"
8 #include "rmnet_private.h"
9 #include "rmnet_vnd.h"
10 
rmnet_map_do_flow_control(struct sk_buff * skb,struct rmnet_port * port,int enable)11 static u8 rmnet_map_do_flow_control(struct sk_buff *skb,
12 				    struct rmnet_port *port,
13 				    int enable)
14 {
15 	struct rmnet_map_header *map_header = (void *)skb->data;
16 	struct rmnet_endpoint *ep;
17 	struct net_device *vnd;
18 	u8 mux_id;
19 	int r;
20 
21 	mux_id = map_header->mux_id;
22 
23 	if (mux_id >= RMNET_MAX_LOGICAL_EP) {
24 		kfree_skb(skb);
25 		return RX_HANDLER_CONSUMED;
26 	}
27 
28 	ep = rmnet_get_endpoint(port, mux_id);
29 	if (!ep) {
30 		kfree_skb(skb);
31 		return RX_HANDLER_CONSUMED;
32 	}
33 
34 	vnd = ep->egress_dev;
35 
36 	/* Ignore the ip family and pass the sequence number for both v4 and v6
37 	 * sequence. User space does not support creating dedicated flows for
38 	 * the 2 protocols
39 	 */
40 	r = rmnet_vnd_do_flow_control(vnd, enable);
41 	if (r) {
42 		kfree_skb(skb);
43 		return RMNET_MAP_COMMAND_UNSUPPORTED;
44 	} else {
45 		return RMNET_MAP_COMMAND_ACK;
46 	}
47 }
48 
rmnet_map_send_ack(struct sk_buff * skb,unsigned char type,struct rmnet_port * port)49 static void rmnet_map_send_ack(struct sk_buff *skb,
50 			       unsigned char type,
51 			       struct rmnet_port *port)
52 {
53 	struct rmnet_map_header *map_header = (void *)skb->data;
54 	struct rmnet_map_control_command *cmd;
55 	struct net_device *dev = skb->dev;
56 
57 	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4)
58 		skb_trim(skb,
59 			 skb->len - sizeof(struct rmnet_map_dl_csum_trailer));
60 
61 	skb->protocol = htons(ETH_P_MAP);
62 
63 	/* Command data immediately follows the MAP header */
64 	cmd = (struct rmnet_map_control_command *)(map_header + 1);
65 	cmd->cmd_type = type & 0x03;
66 
67 	netif_tx_lock(dev);
68 	dev->netdev_ops->ndo_start_xmit(skb, dev);
69 	netif_tx_unlock(dev);
70 }
71 
72 /* Process MAP command frame and send N/ACK message as appropriate. Message cmd
73  * name is decoded here and appropriate handler is called.
74  */
rmnet_map_command(struct sk_buff * skb,struct rmnet_port * port)75 void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port)
76 {
77 	struct rmnet_map_header *map_header = (void *)skb->data;
78 	struct rmnet_map_control_command *cmd;
79 	unsigned char command_name;
80 	unsigned char rc = 0;
81 
82 	/* Command data immediately follows the MAP header */
83 	cmd = (struct rmnet_map_control_command *)(map_header + 1);
84 	command_name = cmd->command_name;
85 
86 	switch (command_name) {
87 	case RMNET_MAP_COMMAND_FLOW_ENABLE:
88 		rc = rmnet_map_do_flow_control(skb, port, 1);
89 		break;
90 
91 	case RMNET_MAP_COMMAND_FLOW_DISABLE:
92 		rc = rmnet_map_do_flow_control(skb, port, 0);
93 		break;
94 
95 	default:
96 		rc = RMNET_MAP_COMMAND_UNSUPPORTED;
97 		kfree_skb(skb);
98 		break;
99 	}
100 	if (rc == RMNET_MAP_COMMAND_ACK)
101 		rmnet_map_send_ack(skb, rc, port);
102 }
103