1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
3  *
4  * RMNET Data virtual network driver
5  */
6 
7 #include <linux/etherdevice.h>
8 #include <linux/ethtool.h>
9 #include <linux/if_arp.h>
10 #include <net/pkt_sched.h>
11 #include "rmnet_config.h"
12 #include "rmnet_handlers.h"
13 #include "rmnet_private.h"
14 #include "rmnet_map.h"
15 #include "rmnet_vnd.h"
16 
17 /* RX/TX Fixup */
18 
rmnet_vnd_rx_fixup(struct sk_buff * skb,struct net_device * dev)19 void rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev)
20 {
21 	struct rmnet_priv *priv = netdev_priv(dev);
22 	struct rmnet_pcpu_stats *pcpu_ptr;
23 
24 	pcpu_ptr = this_cpu_ptr(priv->pcpu_stats);
25 
26 	u64_stats_update_begin(&pcpu_ptr->syncp);
27 	pcpu_ptr->stats.rx_pkts++;
28 	pcpu_ptr->stats.rx_bytes += skb->len;
29 	u64_stats_update_end(&pcpu_ptr->syncp);
30 }
31 
rmnet_vnd_tx_fixup(struct sk_buff * skb,struct net_device * dev)32 void rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev)
33 {
34 	struct rmnet_priv *priv = netdev_priv(dev);
35 	struct rmnet_pcpu_stats *pcpu_ptr;
36 
37 	pcpu_ptr = this_cpu_ptr(priv->pcpu_stats);
38 
39 	u64_stats_update_begin(&pcpu_ptr->syncp);
40 	pcpu_ptr->stats.tx_pkts++;
41 	pcpu_ptr->stats.tx_bytes += skb->len;
42 	u64_stats_update_end(&pcpu_ptr->syncp);
43 }
44 
45 /* Network Device Operations */
46 
rmnet_vnd_start_xmit(struct sk_buff * skb,struct net_device * dev)47 static netdev_tx_t rmnet_vnd_start_xmit(struct sk_buff *skb,
48 					struct net_device *dev)
49 {
50 	struct rmnet_priv *priv;
51 
52 	priv = netdev_priv(dev);
53 	if (priv->real_dev) {
54 		rmnet_egress_handler(skb);
55 	} else {
56 		this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
57 		kfree_skb(skb);
58 	}
59 	return NETDEV_TX_OK;
60 }
61 
rmnet_vnd_headroom(struct rmnet_port * port)62 static int rmnet_vnd_headroom(struct rmnet_port *port)
63 {
64 	u32 headroom;
65 
66 	headroom = sizeof(struct rmnet_map_header);
67 
68 	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4)
69 		headroom += sizeof(struct rmnet_map_ul_csum_header);
70 
71 	return headroom;
72 }
73 
rmnet_vnd_change_mtu(struct net_device * rmnet_dev,int new_mtu)74 static int rmnet_vnd_change_mtu(struct net_device *rmnet_dev, int new_mtu)
75 {
76 	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
77 	struct rmnet_port *port;
78 	u32 headroom;
79 
80 	port = rmnet_get_port_rtnl(priv->real_dev);
81 
82 	headroom = rmnet_vnd_headroom(port);
83 
84 	if (new_mtu < 0 || new_mtu > RMNET_MAX_PACKET_SIZE ||
85 	    new_mtu > (priv->real_dev->mtu - headroom))
86 		return -EINVAL;
87 
88 	rmnet_dev->mtu = new_mtu;
89 	return 0;
90 }
91 
rmnet_vnd_get_iflink(const struct net_device * dev)92 static int rmnet_vnd_get_iflink(const struct net_device *dev)
93 {
94 	struct rmnet_priv *priv = netdev_priv(dev);
95 
96 	return priv->real_dev->ifindex;
97 }
98 
rmnet_vnd_init(struct net_device * dev)99 static int rmnet_vnd_init(struct net_device *dev)
100 {
101 	struct rmnet_priv *priv = netdev_priv(dev);
102 	int err;
103 
104 	priv->pcpu_stats = alloc_percpu(struct rmnet_pcpu_stats);
105 	if (!priv->pcpu_stats)
106 		return -ENOMEM;
107 
108 	err = gro_cells_init(&priv->gro_cells, dev);
109 	if (err) {
110 		free_percpu(priv->pcpu_stats);
111 		return err;
112 	}
113 
114 	return 0;
115 }
116 
rmnet_vnd_uninit(struct net_device * dev)117 static void rmnet_vnd_uninit(struct net_device *dev)
118 {
119 	struct rmnet_priv *priv = netdev_priv(dev);
120 
121 	gro_cells_destroy(&priv->gro_cells);
122 	free_percpu(priv->pcpu_stats);
123 }
124 
rmnet_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * s)125 static void rmnet_get_stats64(struct net_device *dev,
126 			      struct rtnl_link_stats64 *s)
127 {
128 	struct rmnet_priv *priv = netdev_priv(dev);
129 	struct rmnet_vnd_stats total_stats = { };
130 	struct rmnet_pcpu_stats *pcpu_ptr;
131 	struct rmnet_vnd_stats snapshot;
132 	unsigned int cpu, start;
133 
134 	for_each_possible_cpu(cpu) {
135 		pcpu_ptr = per_cpu_ptr(priv->pcpu_stats, cpu);
136 
137 		do {
138 			start = u64_stats_fetch_begin_irq(&pcpu_ptr->syncp);
139 			snapshot = pcpu_ptr->stats;	/* struct assignment */
140 		} while (u64_stats_fetch_retry_irq(&pcpu_ptr->syncp, start));
141 
142 		total_stats.rx_pkts += snapshot.rx_pkts;
143 		total_stats.rx_bytes += snapshot.rx_bytes;
144 		total_stats.tx_pkts += snapshot.tx_pkts;
145 		total_stats.tx_bytes += snapshot.tx_bytes;
146 		total_stats.tx_drops += snapshot.tx_drops;
147 	}
148 
149 	s->rx_packets = total_stats.rx_pkts;
150 	s->rx_bytes = total_stats.rx_bytes;
151 	s->tx_packets = total_stats.tx_pkts;
152 	s->tx_bytes = total_stats.tx_bytes;
153 	s->tx_dropped = total_stats.tx_drops;
154 }
155 
156 static const struct net_device_ops rmnet_vnd_ops = {
157 	.ndo_start_xmit = rmnet_vnd_start_xmit,
158 	.ndo_change_mtu = rmnet_vnd_change_mtu,
159 	.ndo_get_iflink = rmnet_vnd_get_iflink,
160 	.ndo_add_slave  = rmnet_add_bridge,
161 	.ndo_del_slave  = rmnet_del_bridge,
162 	.ndo_init       = rmnet_vnd_init,
163 	.ndo_uninit     = rmnet_vnd_uninit,
164 	.ndo_get_stats64 = rmnet_get_stats64,
165 };
166 
167 static const char rmnet_gstrings_stats[][ETH_GSTRING_LEN] = {
168 	"Checksum ok",
169 	"Bad IPv4 header checksum",
170 	"Checksum valid bit not set",
171 	"Checksum validation failed",
172 	"Checksum error bad buffer",
173 	"Checksum error bad ip version",
174 	"Checksum error bad transport",
175 	"Checksum skipped on ip fragment",
176 	"Checksum skipped",
177 	"Checksum computed in software",
178 	"Checksum computed in hardware",
179 };
180 
rmnet_get_strings(struct net_device * dev,u32 stringset,u8 * buf)181 static void rmnet_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
182 {
183 	switch (stringset) {
184 	case ETH_SS_STATS:
185 		memcpy(buf, &rmnet_gstrings_stats,
186 		       sizeof(rmnet_gstrings_stats));
187 		break;
188 	}
189 }
190 
rmnet_get_sset_count(struct net_device * dev,int sset)191 static int rmnet_get_sset_count(struct net_device *dev, int sset)
192 {
193 	switch (sset) {
194 	case ETH_SS_STATS:
195 		return ARRAY_SIZE(rmnet_gstrings_stats);
196 	default:
197 		return -EOPNOTSUPP;
198 	}
199 }
200 
rmnet_get_ethtool_stats(struct net_device * dev,struct ethtool_stats * stats,u64 * data)201 static void rmnet_get_ethtool_stats(struct net_device *dev,
202 				    struct ethtool_stats *stats, u64 *data)
203 {
204 	struct rmnet_priv *priv = netdev_priv(dev);
205 	struct rmnet_priv_stats *st = &priv->stats;
206 
207 	if (!data)
208 		return;
209 
210 	memcpy(data, st, ARRAY_SIZE(rmnet_gstrings_stats) * sizeof(u64));
211 }
212 
213 static const struct ethtool_ops rmnet_ethtool_ops = {
214 	.get_ethtool_stats = rmnet_get_ethtool_stats,
215 	.get_strings = rmnet_get_strings,
216 	.get_sset_count = rmnet_get_sset_count,
217 };
218 
219 /* Called by kernel whenever a new rmnet<n> device is created. Sets MTU,
220  * flags, ARP type, needed headroom, etc...
221  */
rmnet_vnd_setup(struct net_device * rmnet_dev)222 void rmnet_vnd_setup(struct net_device *rmnet_dev)
223 {
224 	rmnet_dev->netdev_ops = &rmnet_vnd_ops;
225 	rmnet_dev->mtu = RMNET_DFLT_PACKET_SIZE;
226 	rmnet_dev->needed_headroom = RMNET_NEEDED_HEADROOM;
227 	eth_hw_addr_random(rmnet_dev);
228 	rmnet_dev->tx_queue_len = RMNET_TX_QUEUE_LEN;
229 
230 	/* Raw IP mode */
231 	rmnet_dev->header_ops = NULL;  /* No header */
232 	rmnet_dev->type = ARPHRD_RAWIP;
233 	rmnet_dev->hard_header_len = 0;
234 	rmnet_dev->flags &= ~(IFF_BROADCAST | IFF_MULTICAST);
235 
236 	rmnet_dev->needs_free_netdev = true;
237 	rmnet_dev->ethtool_ops = &rmnet_ethtool_ops;
238 
239 	rmnet_dev->features |= NETIF_F_LLTX;
240 
241 	/* This perm addr will be used as interface identifier by IPv6 */
242 	rmnet_dev->addr_assign_type = NET_ADDR_RANDOM;
243 	eth_random_addr(rmnet_dev->perm_addr);
244 }
245 
246 /* Exposed API */
247 
rmnet_vnd_newlink(u8 id,struct net_device * rmnet_dev,struct rmnet_port * port,struct net_device * real_dev,struct rmnet_endpoint * ep,struct netlink_ext_ack * extack)248 int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
249 		      struct rmnet_port *port,
250 		      struct net_device *real_dev,
251 		      struct rmnet_endpoint *ep,
252 		      struct netlink_ext_ack *extack)
253 
254 {
255 	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
256 	u32 headroom;
257 	int rc;
258 
259 	if (rmnet_get_endpoint(port, id)) {
260 		NL_SET_ERR_MSG_MOD(extack, "MUX ID already exists");
261 		return -EBUSY;
262 	}
263 
264 	rmnet_dev->hw_features = NETIF_F_RXCSUM;
265 	rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
266 	rmnet_dev->hw_features |= NETIF_F_SG;
267 
268 	priv->real_dev = real_dev;
269 
270 	headroom = rmnet_vnd_headroom(port);
271 
272 	if (rmnet_vnd_change_mtu(rmnet_dev, real_dev->mtu - headroom)) {
273 		NL_SET_ERR_MSG_MOD(extack, "Invalid MTU on real dev");
274 		return -EINVAL;
275 	}
276 
277 	rc = register_netdevice(rmnet_dev);
278 	if (!rc) {
279 		ep->egress_dev = rmnet_dev;
280 		ep->mux_id = id;
281 		port->nr_rmnet_devs++;
282 
283 		rmnet_dev->rtnl_link_ops = &rmnet_link_ops;
284 
285 		priv->mux_id = id;
286 
287 		netdev_dbg(rmnet_dev, "rmnet dev created\n");
288 	}
289 
290 	return rc;
291 }
292 
rmnet_vnd_dellink(u8 id,struct rmnet_port * port,struct rmnet_endpoint * ep)293 int rmnet_vnd_dellink(u8 id, struct rmnet_port *port,
294 		      struct rmnet_endpoint *ep)
295 {
296 	if (id >= RMNET_MAX_LOGICAL_EP || !ep->egress_dev)
297 		return -EINVAL;
298 
299 	ep->egress_dev = NULL;
300 	port->nr_rmnet_devs--;
301 	return 0;
302 }
303 
rmnet_vnd_do_flow_control(struct net_device * rmnet_dev,int enable)304 int rmnet_vnd_do_flow_control(struct net_device *rmnet_dev, int enable)
305 {
306 	netdev_dbg(rmnet_dev, "Setting VND TX queue state to %d\n", enable);
307 	/* Although we expect similar number of enable/disable
308 	 * commands, optimize for the disable. That is more
309 	 * latency sensitive than enable
310 	 */
311 	if (unlikely(enable))
312 		netif_wake_queue(rmnet_dev);
313 	else
314 		netif_stop_queue(rmnet_dev);
315 
316 	return 0;
317 }
318 
rmnet_vnd_validate_real_dev_mtu(struct net_device * real_dev)319 int rmnet_vnd_validate_real_dev_mtu(struct net_device *real_dev)
320 {
321 	struct hlist_node *tmp_ep;
322 	struct rmnet_endpoint *ep;
323 	struct rmnet_port *port;
324 	unsigned long bkt_ep;
325 	u32 headroom;
326 
327 	port = rmnet_get_port_rtnl(real_dev);
328 
329 	headroom = rmnet_vnd_headroom(port);
330 
331 	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
332 		if (ep->egress_dev->mtu > (real_dev->mtu - headroom))
333 			return -1;
334 	}
335 
336 	return 0;
337 }
338 
rmnet_vnd_update_dev_mtu(struct rmnet_port * port,struct net_device * real_dev)339 int rmnet_vnd_update_dev_mtu(struct rmnet_port *port,
340 			     struct net_device *real_dev)
341 {
342 	struct hlist_node *tmp_ep;
343 	struct rmnet_endpoint *ep;
344 	unsigned long bkt_ep;
345 	u32 headroom;
346 
347 	headroom = rmnet_vnd_headroom(port);
348 
349 	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
350 		if (ep->egress_dev->mtu <= (real_dev->mtu - headroom))
351 			continue;
352 
353 		if (rmnet_vnd_change_mtu(ep->egress_dev,
354 					 real_dev->mtu - headroom))
355 			return -1;
356 	}
357 
358 	return 0;
359 }
360