1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright 2011-2014 Autronica Fire and Security AS
  3 *
  4 * Author(s):
  5 *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
  6 */
  7
  8#include "hsr_forward.h"
  9#include <linux/types.h>
 10#include <linux/skbuff.h>
 11#include <linux/etherdevice.h>
 12#include <linux/if_vlan.h>
 13#include "hsr_main.h"
 14#include "hsr_framereg.h"
 15
 16struct hsr_node;
 17
 18struct hsr_frame_info {
 19	struct sk_buff *skb_std;
 20	struct sk_buff *skb_hsr;
 21	struct hsr_port *port_rcv;
 22	struct hsr_node *node_src;
 23	u16 sequence_nr;
 24	bool is_supervision;
 25	bool is_vlan;
 26	bool is_local_dest;
 27	bool is_local_exclusive;
 28};
 29
 30/* The uses I can see for these HSR supervision frames are:
 31 * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
 32 *    22") to reset any sequence_nr counters belonging to that node. Useful if
 33 *    the other node's counter has been reset for some reason.
 34 *    --
 35 *    Or not - resetting the counter and bridging the frame would create a
 36 *    loop, unfortunately.
 37 *
 38 * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
 39 *    frame is received from a particular node, we know something is wrong.
 40 *    We just register these (as with normal frames) and throw them away.
 41 *
 42 * 3) Allow different MAC addresses for the two slave interfaces, using the
 43 *    MacAddressA field.
 44 */
 45static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
 46{
 47	struct ethhdr *eth_hdr;
 48	struct hsr_sup_tag *hsr_sup_tag;
 49	struct hsrv1_ethhdr_sp *hsr_V1_hdr;
 50
 51	WARN_ON_ONCE(!skb_mac_header_was_set(skb));
 52	eth_hdr = (struct ethhdr *)skb_mac_header(skb);
 53
 54	/* Correct addr? */
 55	if (!ether_addr_equal(eth_hdr->h_dest,
 56			      hsr->sup_multicast_addr))
 57		return false;
 58
 59	/* Correct ether type?. */
 60	if (!(eth_hdr->h_proto == htons(ETH_P_PRP) ||
 61	      eth_hdr->h_proto == htons(ETH_P_HSR)))
 62		return false;
 63
 64	/* Get the supervision header from correct location. */
 65	if (eth_hdr->h_proto == htons(ETH_P_HSR)) { /* Okay HSRv1. */
 66		hsr_V1_hdr = (struct hsrv1_ethhdr_sp *)skb_mac_header(skb);
 67		if (hsr_V1_hdr->hsr.encap_proto != htons(ETH_P_PRP))
 68			return false;
 69
 70		hsr_sup_tag = &hsr_V1_hdr->hsr_sup;
 71	} else {
 72		hsr_sup_tag =
 73		     &((struct hsrv0_ethhdr_sp *)skb_mac_header(skb))->hsr_sup;
 74	}
 75
 76	if (hsr_sup_tag->HSR_TLV_type != HSR_TLV_ANNOUNCE &&
 77	    hsr_sup_tag->HSR_TLV_type != HSR_TLV_LIFE_CHECK)
 78		return false;
 79	if (hsr_sup_tag->HSR_TLV_length != 12 &&
 80	    hsr_sup_tag->HSR_TLV_length != sizeof(struct hsr_sup_payload))
 81		return false;
 82
 83	return true;
 84}
 85
 86static struct sk_buff *create_stripped_skb(struct sk_buff *skb_in,
 87					   struct hsr_frame_info *frame)
 88{
 89	struct sk_buff *skb;
 90	int copylen;
 91	unsigned char *dst, *src;
 92
 93	skb_pull(skb_in, HSR_HLEN);
 94	skb = __pskb_copy(skb_in, skb_headroom(skb_in) - HSR_HLEN, GFP_ATOMIC);
 95	skb_push(skb_in, HSR_HLEN);
 96	if (!skb)
 97		return NULL;
 98
 99	skb_reset_mac_header(skb);
100
101	if (skb->ip_summed == CHECKSUM_PARTIAL)
102		skb->csum_start -= HSR_HLEN;
103
104	copylen = 2 * ETH_ALEN;
105	if (frame->is_vlan)
106		copylen += VLAN_HLEN;
107	src = skb_mac_header(skb_in);
108	dst = skb_mac_header(skb);
109	memcpy(dst, src, copylen);
110
111	skb->protocol = eth_hdr(skb)->h_proto;
112	return skb;
113}
114
115static struct sk_buff *frame_get_stripped_skb(struct hsr_frame_info *frame,
116					      struct hsr_port *port)
117{
118	if (!frame->skb_std)
119		frame->skb_std = create_stripped_skb(frame->skb_hsr, frame);
120	return skb_clone(frame->skb_std, GFP_ATOMIC);
121}
122
123static void hsr_fill_tag(struct sk_buff *skb, struct hsr_frame_info *frame,
124			 struct hsr_port *port, u8 proto_version)
125{
126	struct hsr_ethhdr *hsr_ethhdr;
127	int lane_id;
128	int lsdu_size;
129
130	if (port->type == HSR_PT_SLAVE_A)
131		lane_id = 0;
132	else
133		lane_id = 1;
134
135	lsdu_size = skb->len - 14;
136	if (frame->is_vlan)
137		lsdu_size -= 4;
138
139	hsr_ethhdr = (struct hsr_ethhdr *)skb_mac_header(skb);
140
141	set_hsr_tag_path(&hsr_ethhdr->hsr_tag, lane_id);
142	set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, lsdu_size);
143	hsr_ethhdr->hsr_tag.sequence_nr = htons(frame->sequence_nr);
144	hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
145	hsr_ethhdr->ethhdr.h_proto = htons(proto_version ?
146			ETH_P_HSR : ETH_P_PRP);
147}
148
149static struct sk_buff *create_tagged_skb(struct sk_buff *skb_o,
150					 struct hsr_frame_info *frame,
151					 struct hsr_port *port)
152{
153	int movelen;
154	unsigned char *dst, *src;
155	struct sk_buff *skb;
156
157	/* Create the new skb with enough headroom to fit the HSR tag */
158	skb = __pskb_copy(skb_o, skb_headroom(skb_o) + HSR_HLEN, GFP_ATOMIC);
159	if (!skb)
160		return NULL;
161	skb_reset_mac_header(skb);
162
163	if (skb->ip_summed == CHECKSUM_PARTIAL)
164		skb->csum_start += HSR_HLEN;
165
166	movelen = ETH_HLEN;
167	if (frame->is_vlan)
168		movelen += VLAN_HLEN;
169
170	src = skb_mac_header(skb);
171	dst = skb_push(skb, HSR_HLEN);
172	memmove(dst, src, movelen);
173	skb_reset_mac_header(skb);
174
175	hsr_fill_tag(skb, frame, port, port->hsr->prot_version);
176
177	return skb;
178}
179
180/* If the original frame was an HSR tagged frame, just clone it to be sent
181 * unchanged. Otherwise, create a private frame especially tagged for 'port'.
182 */
183static struct sk_buff *frame_get_tagged_skb(struct hsr_frame_info *frame,
184					    struct hsr_port *port)
185{
186	if (frame->skb_hsr)
187		return skb_clone(frame->skb_hsr, GFP_ATOMIC);
188
189	if (port->type != HSR_PT_SLAVE_A && port->type != HSR_PT_SLAVE_B) {
190		WARN_ONCE(1, "HSR: Bug: trying to create a tagged frame for a non-ring port");
191		return NULL;
192	}
193
194	return create_tagged_skb(frame->skb_std, frame, port);
195}
196
197static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
198			       struct hsr_node *node_src)
199{
200	bool was_multicast_frame;
201	int res;
202
203	was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
204	hsr_addr_subst_source(node_src, skb);
205	skb_pull(skb, ETH_HLEN);
206	res = netif_rx(skb);
207	if (res == NET_RX_DROP) {
208		dev->stats.rx_dropped++;
209	} else {
210		dev->stats.rx_packets++;
211		dev->stats.rx_bytes += skb->len;
212		if (was_multicast_frame)
213			dev->stats.multicast++;
214	}
215}
216
217static int hsr_xmit(struct sk_buff *skb, struct hsr_port *port,
218		    struct hsr_frame_info *frame)
219{
220	if (frame->port_rcv->type == HSR_PT_MASTER) {
221		hsr_addr_subst_dest(frame->node_src, skb, port);
222
223		/* Address substitution (IEC62439-3 pp 26, 50): replace mac
224		 * address of outgoing frame with that of the outgoing slave's.
225		 */
226		ether_addr_copy(eth_hdr(skb)->h_source, port->dev->dev_addr);
227	}
228	return dev_queue_xmit(skb);
229}
230
231/* Forward the frame through all devices except:
232 * - Back through the receiving device
233 * - If it's a HSR frame: through a device where it has passed before
234 * - To the local HSR master only if the frame is directly addressed to it, or
235 *   a non-supervision multicast or broadcast frame.
236 *
237 * HSR slave devices should insert a HSR tag into the frame, or forward the
238 * frame unchanged if it's already tagged. Interlink devices should strip HSR
239 * tags if they're of the non-HSR type (but only after duplicate discard). The
240 * master device always strips HSR tags.
241 */
242static void hsr_forward_do(struct hsr_frame_info *frame)
243{
244	struct hsr_port *port;
245	struct sk_buff *skb;
246
247	hsr_for_each_port(frame->port_rcv->hsr, port) {
248		/* Don't send frame back the way it came */
249		if (port == frame->port_rcv)
250			continue;
251
252		/* Don't deliver locally unless we should */
253		if (port->type == HSR_PT_MASTER && !frame->is_local_dest)
254			continue;
255
256		/* Deliver frames directly addressed to us to master only */
257		if (port->type != HSR_PT_MASTER && frame->is_local_exclusive)
258			continue;
259
260		/* Don't send frame over port where it has been sent before */
261		if (hsr_register_frame_out(port, frame->node_src,
262					   frame->sequence_nr))
263			continue;
264
265		if (frame->is_supervision && port->type == HSR_PT_MASTER) {
266			hsr_handle_sup_frame(frame->skb_hsr,
267					     frame->node_src,
268					     frame->port_rcv);
269			continue;
270		}
271
272		if (port->type != HSR_PT_MASTER)
273			skb = frame_get_tagged_skb(frame, port);
274		else
275			skb = frame_get_stripped_skb(frame, port);
276		if (!skb) {
277			/* FIXME: Record the dropped frame? */
278			continue;
279		}
280
281		skb->dev = port->dev;
282		if (port->type == HSR_PT_MASTER)
283			hsr_deliver_master(skb, port->dev, frame->node_src);
284		else
285			hsr_xmit(skb, port, frame);
286	}
287}
288
289static void check_local_dest(struct hsr_priv *hsr, struct sk_buff *skb,
290			     struct hsr_frame_info *frame)
291{
292	if (hsr_addr_is_self(hsr, eth_hdr(skb)->h_dest)) {
293		frame->is_local_exclusive = true;
294		skb->pkt_type = PACKET_HOST;
295	} else {
296		frame->is_local_exclusive = false;
297	}
298
299	if (skb->pkt_type == PACKET_HOST ||
300	    skb->pkt_type == PACKET_MULTICAST ||
301	    skb->pkt_type == PACKET_BROADCAST) {
302		frame->is_local_dest = true;
303	} else {
304		frame->is_local_dest = false;
305	}
306}
307
308static int hsr_fill_frame_info(struct hsr_frame_info *frame,
309			       struct sk_buff *skb, struct hsr_port *port)
310{
311	struct ethhdr *ethhdr;
312	unsigned long irqflags;
313
314	frame->is_supervision = is_supervision_frame(port->hsr, skb);
315	frame->node_src = hsr_get_node(port, skb, frame->is_supervision);
316	if (!frame->node_src)
317		return -1; /* Unknown node and !is_supervision, or no mem */
318
319	ethhdr = (struct ethhdr *)skb_mac_header(skb);
320	frame->is_vlan = false;
321	if (ethhdr->h_proto == htons(ETH_P_8021Q)) {
322		frame->is_vlan = true;
323		/* FIXME: */
324		WARN_ONCE(1, "HSR: VLAN not yet supported");
325	}
326	if (ethhdr->h_proto == htons(ETH_P_PRP) ||
327	    ethhdr->h_proto == htons(ETH_P_HSR)) {
328		frame->skb_std = NULL;
329		frame->skb_hsr = skb;
330		frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
331	} else {
332		frame->skb_std = skb;
333		frame->skb_hsr = NULL;
334		/* Sequence nr for the master node */
335		spin_lock_irqsave(&port->hsr->seqnr_lock, irqflags);
336		frame->sequence_nr = port->hsr->sequence_nr;
337		port->hsr->sequence_nr++;
338		spin_unlock_irqrestore(&port->hsr->seqnr_lock, irqflags);
339	}
340
341	frame->port_rcv = port;
342	check_local_dest(port->hsr, skb, frame);
343
344	return 0;
345}
346
347/* Must be called holding rcu read lock (because of the port parameter) */
348void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
349{
350	struct hsr_frame_info frame;
351
352	if (skb_mac_header(skb) != skb->data) {
353		WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n",
354			  __FILE__, __LINE__, port->dev->name);
355		goto out_drop;
356	}
357
358	if (hsr_fill_frame_info(&frame, skb, port) < 0)
359		goto out_drop;
360	hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
361	hsr_forward_do(&frame);
362	/* Gets called for ingress frames as well as egress from master port.
363	 * So check and increment stats for master port only here.
364	 */
365	if (port->type == HSR_PT_MASTER) {
366		port->dev->stats.tx_packets++;
367		port->dev->stats.tx_bytes += skb->len;
368	}
369
370	if (frame.skb_hsr)
371		kfree_skb(frame.skb_hsr);
372	if (frame.skb_std)
373		kfree_skb(frame.skb_std);
374	return;
375
376out_drop:
377	port->dev->stats.tx_dropped++;
378	kfree_skb(skb);
379}