summaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
blob: 3d00b32323084a3b5f05622e762d0e4e1b0526b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
 *
 * RMNET Data ingress/egress handler
 */

#include <linux/netdevice.h>
#include <linux/netdev_features.h>
#include <linux/if_arp.h>
#include <net/sock.h>
#include "rmnet_private.h"
#include "rmnet_config.h"
#include "rmnet_vnd.h"
#include "rmnet_map.h"
#include "rmnet_handlers.h"

#define RMNET_IP_VERSION_4 0x40
#define RMNET_IP_VERSION_6 0x60

/* Helper Functions */

static void rmnet_set_skb_proto(struct sk_buff *skb)
{
	switch (skb->data[0] & 0xF0) {
	case RMNET_IP_VERSION_4:
		skb->protocol = htons(ETH_P_IP);
		break;
	case RMNET_IP_VERSION_6:
		skb->protocol = htons(ETH_P_IPV6);
		break;
	default:
		skb->protocol = htons(ETH_P_MAP);
		break;
	}
}

/* Generic handler */

static void
rmnet_deliver_skb(struct sk_buff *skb)
{
	struct rmnet_priv *priv = netdev_priv(skb->dev);

	skb_reset_transport_header(skb);
	skb_reset_network_header(skb);
	rmnet_vnd_rx_fixup(skb, skb->dev);

	skb->pkt_type = PACKET_HOST;
	skb_set_mac_header(skb, 0);
	gro_cells_receive(&priv->gro_cells, skb);
}

/* MAP handler */

static void
__rmnet_map_ingress_handler(struct sk_buff *skb,
			    struct rmnet_port *port)
{
	struct rmnet_endpoint *ep;
	u16 len, pad;
	u8 mux_id;

	if (RMNET_MAP_GET_CD_BIT(skb)) {
		if (port->data_format & RMNET_FLAGS_INGRESS_MAP_COMMANDS)
			return rmnet_map_command(skb, port);

		goto free_skb;
	}

	mux_id = RMNET_MAP_GET_MUX_ID(skb);
	pad = RMNET_MAP_GET_PAD(skb);
	len = RMNET_MAP_GET_LENGTH(skb) - pad;

	if (mux_id >= RMNET_MAX_LOGICAL_EP)
		goto free_skb;

	ep = rmnet_get_endpoint(port, mux_id);
	if (!ep)
		goto free_skb;

	skb->dev = ep->egress_dev;

	/* Subtract MAP header */
	skb_pull(skb, sizeof(struct rmnet_map_header));
	rmnet_set_skb_proto(skb);

	if (port->data_format & RMNET_FLAGS_INGRESS_MAP_CKSUMV4) {
		if (!rmnet_map_checksum_downlink_packet(skb, len + pad))
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	skb_trim(skb, len);
	rmnet_deliver_skb(skb);
	return;

free_skb:
	kfree_skb(skb);
}

static void
rmnet_map_ingress_handler(struct sk_buff *skb,
			  struct rmnet_port *port)
{
	struct sk_buff *skbn;

	if (skb->dev->type == ARPHRD_ETHER) {
		if (pskb_expand_head(skb, ETH_HLEN, 0, GFP_ATOMIC)) {
			kfree_skb(skb);
			return;
		}

		skb_push(skb, ETH_HLEN);
	}

	if (port->data_format & RMNET_FLAGS_INGRESS_DEAGGREGATION) {
		while ((skbn = rmnet_map_deaggregate(skb, port)) != NULL)
			__rmnet_map_ingress_handler(skbn, port);

		consume_skb(skb);
	} else {
		__rmnet_map_ingress_handler(skb, port);
	}
}

static int rmnet_map_egress_handler(struct sk_buff *skb,
				    struct rmnet_port *port, u8 mux_id,
				    struct net_device *orig_dev)
{
	int required_headroom, additional_header_len;
	struct rmnet_map_header *map_header;

	additional_header_len = 0;
	required_headroom = sizeof(struct rmnet_map_header);

	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4) {
		additional_header_len = sizeof(struct rmnet_map_ul_csum_header);
		required_headroom += additional_header_len;
	}

	if (skb_headroom(skb) < required_headroom) {
		if (pskb_expand_head(skb, required_headroom, 0, GFP_ATOMIC))
			return -ENOMEM;
	}

	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4)
		rmnet_map_checksum_uplink_packet(skb, orig_dev);

	map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);
	if (!map_header)
		return -ENOMEM;

	map_header->mux_id = mux_id;

	skb->protocol = htons(ETH_P_MAP);

	return 0;
}

static void
rmnet_bridge_handler(struct sk_buff *skb, struct net_device *bridge_dev)
{
	if (skb_mac_header_was_set(skb))
		skb_push(skb, skb->mac_len);

	if (bridge_dev) {
		skb->dev = bridge_dev;
		dev_queue_xmit(skb);
	}
}

/* Ingress / Egress Entry Points */

/* Processes packet as per ingress data format for receiving device. Logical
 * endpoint is determined from packet inspection. Packet is then sent to the
 * egress device listed in the logical endpoint configuration.
 */
rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
{
	struct sk_buff *skb = *pskb;
	struct rmnet_port *port;
	struct net_device *dev;

	if (!skb)
		goto done;

	if (skb_linearize(skb)) {
		kfree_skb(skb);
		goto done;
	}

	if (skb->pkt_type == PACKET_LOOPBACK)
		return RX_HANDLER_PASS;

	dev = skb->dev;
	port = rmnet_get_port_rcu(dev);
	if (unlikely(!port)) {
		atomic_long_inc(&skb->dev->rx_nohandler);
		kfree_skb(skb);
		goto done;
	}

	switch (port->rmnet_mode) {
	case RMNET_EPMODE_VND:
		rmnet_map_ingress_handler(skb, port);
		break;
	case RMNET_EPMODE_BRIDGE:
		rmnet_bridge_handler(skb, port->bridge_ep);
		break;
	}

done:
	return RX_HANDLER_CONSUMED;
}

/* Modifies packet as per logical endpoint configuration and egress data format
 * for egress device configured in logical endpoint. Packet is then transmitted
 * on the egress device.
 */
void rmnet_egress_handler(struct sk_buff *skb)
{
	struct net_device *orig_dev;
	struct rmnet_port *port;
	struct rmnet_priv *priv;
	u8 mux_id;

	sk_pacing_shift_update(skb->sk, 8);

	orig_dev = skb->dev;
	priv = netdev_priv(orig_dev);
	skb->dev = priv->real_dev;
	mux_id = priv->mux_id;

	port = rmnet_get_port_rcu(skb->dev);
	if (!port)
		goto drop;

	if (rmnet_map_egress_handler(skb, port, mux_id, orig_dev))
		goto drop;

	rmnet_vnd_tx_fixup(skb, orig_dev);

	dev_queue_xmit(skb);
	return;

drop:
	this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
	kfree_skb(skb);
}