xref: /openbmc/linux/drivers/net/xen-netback/hash.c (revision 8f91116f)
1 /*
2  * Copyright (c) 2016 Citrix Systems Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License version 2
6  * as published by the Free Softare Foundation; or, when distributed
7  * separately from the Linux kernel or incorporated into other
8  * software packages, subject to the following license:
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this source file (the "Software"), to deal in the Software without
12  * restriction, including without limitation the rights to use, copy, modify,
13  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
14  * and to permit persons to whom the Software is furnished to do so, subject to
15  * the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
25  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
26  * IN THE SOFTWARE.
27  */
28 
29 #define XEN_NETIF_DEFINE_TOEPLITZ
30 
31 #include "common.h"
32 #include <linux/vmalloc.h>
33 #include <linux/rculist.h>
34 
35 static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,
36 			    unsigned int len, u32 val)
37 {
38 	struct xenvif_hash_cache_entry *new, *entry, *oldest;
39 	unsigned long flags;
40 	bool found;
41 
42 	new = kmalloc(sizeof(*entry), GFP_ATOMIC);
43 	if (!new)
44 		return;
45 
46 	memcpy(new->tag, tag, len);
47 	new->len = len;
48 	new->val = val;
49 
50 	spin_lock_irqsave(&vif->hash.cache.lock, flags);
51 
52 	found = false;
53 	oldest = NULL;
54 	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
55 				lockdep_is_held(&vif->hash.cache.lock)) {
56 		/* Make sure we don't add duplicate entries */
57 		if (entry->len == len &&
58 		    memcmp(entry->tag, tag, len) == 0)
59 			found = true;
60 		if (!oldest || entry->seq < oldest->seq)
61 			oldest = entry;
62 	}
63 
64 	if (!found) {
65 		new->seq = atomic_inc_return(&vif->hash.cache.seq);
66 		list_add_rcu(&new->link, &vif->hash.cache.list);
67 
68 		if (++vif->hash.cache.count > xenvif_hash_cache_size) {
69 			list_del_rcu(&oldest->link);
70 			vif->hash.cache.count--;
71 			kfree_rcu(oldest, rcu);
72 		}
73 	}
74 
75 	spin_unlock_irqrestore(&vif->hash.cache.lock, flags);
76 
77 	if (found)
78 		kfree(new);
79 }
80 
81 static u32 xenvif_new_hash(struct xenvif *vif, const u8 *data,
82 			   unsigned int len)
83 {
84 	u32 val;
85 
86 	val = xen_netif_toeplitz_hash(vif->hash.key,
87 				      sizeof(vif->hash.key),
88 				      data, len);
89 
90 	if (xenvif_hash_cache_size != 0)
91 		xenvif_add_hash(vif, data, len, val);
92 
93 	return val;
94 }
95 
96 static void xenvif_flush_hash(struct xenvif *vif)
97 {
98 	struct xenvif_hash_cache_entry *entry, *n;
99 	unsigned long flags;
100 
101 	if (xenvif_hash_cache_size == 0)
102 		return;
103 
104 	spin_lock_irqsave(&vif->hash.cache.lock, flags);
105 
106 	list_for_each_entry_safe(entry, n, &vif->hash.cache.list, link) {
107 		list_del_rcu(&entry->link);
108 		vif->hash.cache.count--;
109 		kfree_rcu(entry, rcu);
110 	}
111 
112 	spin_unlock_irqrestore(&vif->hash.cache.lock, flags);
113 }
114 
115 static u32 xenvif_find_hash(struct xenvif *vif, const u8 *data,
116 			    unsigned int len)
117 {
118 	struct xenvif_hash_cache_entry *entry;
119 	u32 val;
120 	bool found;
121 
122 	if (len >= XEN_NETBK_HASH_TAG_SIZE)
123 		return 0;
124 
125 	if (xenvif_hash_cache_size == 0)
126 		return xenvif_new_hash(vif, data, len);
127 
128 	rcu_read_lock();
129 
130 	found = false;
131 
132 	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
133 		if (entry->len == len &&
134 		    memcmp(entry->tag, data, len) == 0) {
135 			val = entry->val;
136 			entry->seq = atomic_inc_return(&vif->hash.cache.seq);
137 			found = true;
138 			break;
139 		}
140 	}
141 
142 	rcu_read_unlock();
143 
144 	if (!found)
145 		val = xenvif_new_hash(vif, data, len);
146 
147 	return val;
148 }
149 
150 void xenvif_set_skb_hash(struct xenvif *vif, struct sk_buff *skb)
151 {
152 	struct flow_keys flow;
153 	u32 hash = 0;
154 	enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
155 	u32 flags = vif->hash.flags;
156 	bool has_tcp_hdr;
157 
158 	/* Quick rejection test: If the network protocol doesn't
159 	 * correspond to any enabled hash type then there's no point
160 	 * in parsing the packet header.
161 	 */
162 	switch (skb->protocol) {
163 	case htons(ETH_P_IP):
164 		if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
165 			     XEN_NETIF_CTRL_HASH_TYPE_IPV4))
166 			break;
167 
168 		goto done;
169 
170 	case htons(ETH_P_IPV6):
171 		if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP |
172 			     XEN_NETIF_CTRL_HASH_TYPE_IPV6))
173 			break;
174 
175 		goto done;
176 
177 	default:
178 		goto done;
179 	}
180 
181 	memset(&flow, 0, sizeof(flow));
182 	if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
183 		goto done;
184 
185 	has_tcp_hdr = (flow.basic.ip_proto == IPPROTO_TCP) &&
186 		      !(flow.control.flags & FLOW_DIS_IS_FRAGMENT);
187 
188 	switch (skb->protocol) {
189 	case htons(ETH_P_IP):
190 		if (has_tcp_hdr &&
191 		    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)) {
192 			u8 data[12];
193 
194 			memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
195 			memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
196 			memcpy(&data[8], &flow.ports.src, 2);
197 			memcpy(&data[10], &flow.ports.dst, 2);
198 
199 			hash = xenvif_find_hash(vif, data, sizeof(data));
200 			type = PKT_HASH_TYPE_L4;
201 		} else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4) {
202 			u8 data[8];
203 
204 			memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
205 			memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
206 
207 			hash = xenvif_find_hash(vif, data, sizeof(data));
208 			type = PKT_HASH_TYPE_L3;
209 		}
210 
211 		break;
212 
213 	case htons(ETH_P_IPV6):
214 		if (has_tcp_hdr &&
215 		    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)) {
216 			u8 data[36];
217 
218 			memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
219 			memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
220 			memcpy(&data[32], &flow.ports.src, 2);
221 			memcpy(&data[34], &flow.ports.dst, 2);
222 
223 			hash = xenvif_find_hash(vif, data, sizeof(data));
224 			type = PKT_HASH_TYPE_L4;
225 		} else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6) {
226 			u8 data[32];
227 
228 			memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
229 			memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
230 
231 			hash = xenvif_find_hash(vif, data, sizeof(data));
232 			type = PKT_HASH_TYPE_L3;
233 		}
234 
235 		break;
236 	}
237 
238 done:
239 	if (type == PKT_HASH_TYPE_NONE)
240 		skb_clear_hash(skb);
241 	else
242 		__skb_set_sw_hash(skb, hash, type == PKT_HASH_TYPE_L4);
243 }
244 
245 u32 xenvif_set_hash_alg(struct xenvif *vif, u32 alg)
246 {
247 	switch (alg) {
248 	case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
249 	case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
250 		break;
251 
252 	default:
253 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
254 	}
255 
256 	vif->hash.alg = alg;
257 
258 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
259 }
260 
261 u32 xenvif_get_hash_flags(struct xenvif *vif, u32 *flags)
262 {
263 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
264 		return XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
265 
266 	*flags = XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
267 		 XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
268 		 XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
269 		 XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
270 
271 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
272 }
273 
274 u32 xenvif_set_hash_flags(struct xenvif *vif, u32 flags)
275 {
276 	if (flags & ~(XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
277 		      XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
278 		      XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
279 		      XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP))
280 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
281 
282 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
283 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
284 
285 	vif->hash.flags = flags;
286 
287 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
288 }
289 
290 u32 xenvif_set_hash_key(struct xenvif *vif, u32 gref, u32 len)
291 {
292 	u8 *key = vif->hash.key;
293 	struct gnttab_copy copy_op = {
294 		.source.u.ref = gref,
295 		.source.domid = vif->domid,
296 		.dest.u.gmfn = virt_to_gfn(key),
297 		.dest.domid = DOMID_SELF,
298 		.dest.offset = xen_offset_in_page(key),
299 		.len = len,
300 		.flags = GNTCOPY_source_gref
301 	};
302 
303 	if (len > XEN_NETBK_MAX_HASH_KEY_SIZE)
304 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
305 
306 	if (copy_op.len != 0) {
307 		gnttab_batch_copy(&copy_op, 1);
308 
309 		if (copy_op.status != GNTST_okay)
310 			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
311 	}
312 
313 	/* Clear any remaining key octets */
314 	if (len < XEN_NETBK_MAX_HASH_KEY_SIZE)
315 		memset(key + len, 0, XEN_NETBK_MAX_HASH_KEY_SIZE - len);
316 
317 	xenvif_flush_hash(vif);
318 
319 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
320 }
321 
322 u32 xenvif_set_hash_mapping_size(struct xenvif *vif, u32 size)
323 {
324 	if (size > XEN_NETBK_MAX_HASH_MAPPING_SIZE)
325 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
326 
327 	vif->hash.size = size;
328 	memset(vif->hash.mapping[vif->hash.mapping_sel], 0,
329 	       sizeof(u32) * size);
330 
331 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
332 }
333 
334 u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,
335 			    u32 off)
336 {
337 	u32 *mapping = vif->hash.mapping[!vif->hash.mapping_sel];
338 	unsigned int nr = 1;
339 	struct gnttab_copy copy_op[2] = {{
340 		.source.u.ref = gref,
341 		.source.domid = vif->domid,
342 		.dest.domid = DOMID_SELF,
343 		.len = len * sizeof(*mapping),
344 		.flags = GNTCOPY_source_gref
345 	}};
346 
347 	if ((off + len < off) || (off + len > vif->hash.size) ||
348 	    len > XEN_PAGE_SIZE / sizeof(*mapping))
349 		return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
350 
351 	copy_op[0].dest.u.gmfn = virt_to_gfn(mapping + off);
352 	copy_op[0].dest.offset = xen_offset_in_page(mapping + off);
353 	if (copy_op[0].dest.offset + copy_op[0].len > XEN_PAGE_SIZE) {
354 		copy_op[1] = copy_op[0];
355 		copy_op[1].source.offset = XEN_PAGE_SIZE - copy_op[0].dest.offset;
356 		copy_op[1].dest.u.gmfn = virt_to_gfn(mapping + off + len);
357 		copy_op[1].dest.offset = 0;
358 		copy_op[1].len = copy_op[0].len - copy_op[1].source.offset;
359 		copy_op[0].len = copy_op[1].source.offset;
360 		nr = 2;
361 	}
362 
363 	memcpy(mapping, vif->hash.mapping[vif->hash.mapping_sel],
364 	       vif->hash.size * sizeof(*mapping));
365 
366 	if (copy_op[0].len != 0) {
367 		gnttab_batch_copy(copy_op, nr);
368 
369 		if (copy_op[0].status != GNTST_okay ||
370 		    copy_op[nr - 1].status != GNTST_okay)
371 			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
372 	}
373 
374 	while (len-- != 0)
375 		if (mapping[off++] >= vif->num_queues)
376 			return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
377 
378 	vif->hash.mapping_sel = !vif->hash.mapping_sel;
379 
380 	return XEN_NETIF_CTRL_STATUS_SUCCESS;
381 }
382 
383 #ifdef CONFIG_DEBUG_FS
384 void xenvif_dump_hash_info(struct xenvif *vif, struct seq_file *m)
385 {
386 	unsigned int i;
387 
388 	switch (vif->hash.alg) {
389 	case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
390 		seq_puts(m, "Hash Algorithm: TOEPLITZ\n");
391 		break;
392 
393 	case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
394 		seq_puts(m, "Hash Algorithm: NONE\n");
395 		fallthrough;
396 	default:
397 		return;
398 	}
399 
400 	if (vif->hash.flags) {
401 		seq_puts(m, "\nHash Flags:\n");
402 
403 		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4)
404 			seq_puts(m, "- IPv4\n");
405 		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
406 			seq_puts(m, "- IPv4 + TCP\n");
407 		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6)
408 			seq_puts(m, "- IPv6\n");
409 		if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
410 			seq_puts(m, "- IPv6 + TCP\n");
411 	}
412 
413 	seq_puts(m, "\nHash Key:\n");
414 
415 	for (i = 0; i < XEN_NETBK_MAX_HASH_KEY_SIZE; ) {
416 		unsigned int j, n;
417 
418 		n = 8;
419 		if (i + n >= XEN_NETBK_MAX_HASH_KEY_SIZE)
420 			n = XEN_NETBK_MAX_HASH_KEY_SIZE - i;
421 
422 		seq_printf(m, "[%2u - %2u]: ", i, i + n - 1);
423 
424 		for (j = 0; j < n; j++, i++)
425 			seq_printf(m, "%02x ", vif->hash.key[i]);
426 
427 		seq_puts(m, "\n");
428 	}
429 
430 	if (vif->hash.size != 0) {
431 		const u32 *mapping = vif->hash.mapping[vif->hash.mapping_sel];
432 
433 		seq_puts(m, "\nHash Mapping:\n");
434 
435 		for (i = 0; i < vif->hash.size; ) {
436 			unsigned int j, n;
437 
438 			n = 8;
439 			if (i + n >= vif->hash.size)
440 				n = vif->hash.size - i;
441 
442 			seq_printf(m, "[%4u - %4u]: ", i, i + n - 1);
443 
444 			for (j = 0; j < n; j++, i++)
445 				seq_printf(m, "%4u ", mapping[i]);
446 
447 			seq_puts(m, "\n");
448 		}
449 	}
450 }
451 #endif /* CONFIG_DEBUG_FS */
452 
453 void xenvif_init_hash(struct xenvif *vif)
454 {
455 	if (xenvif_hash_cache_size == 0)
456 		return;
457 
458 	BUG_ON(vif->hash.cache.count);
459 
460 	spin_lock_init(&vif->hash.cache.lock);
461 	INIT_LIST_HEAD(&vif->hash.cache.list);
462 }
463 
464 void xenvif_deinit_hash(struct xenvif *vif)
465 {
466 	xenvif_flush_hash(vif);
467 }
468