linux/drivers/net/xen-netback/hash.c
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   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
  35static 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
  81static 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
  96static void xenvif_flush_hash(struct xenvif *vif)
  97{
  98        struct xenvif_hash_cache_entry *entry;
  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_rcu(entry, &vif->hash.cache.list, link,
 107                                lockdep_is_held(&vif->hash.cache.lock)) {
 108                list_del_rcu(&entry->link);
 109                vif->hash.cache.count--;
 110                kfree_rcu(entry, rcu);
 111        }
 112
 113        spin_unlock_irqrestore(&vif->hash.cache.lock, flags);
 114}
 115
 116static u32 xenvif_find_hash(struct xenvif *vif, const u8 *data,
 117                            unsigned int len)
 118{
 119        struct xenvif_hash_cache_entry *entry;
 120        u32 val;
 121        bool found;
 122
 123        if (len >= XEN_NETBK_HASH_TAG_SIZE)
 124                return 0;
 125
 126        if (xenvif_hash_cache_size == 0)
 127                return xenvif_new_hash(vif, data, len);
 128
 129        rcu_read_lock();
 130
 131        found = false;
 132
 133        list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
 134                if (entry->len == len &&
 135                    memcmp(entry->tag, data, len) == 0) {
 136                        val = entry->val;
 137                        entry->seq = atomic_inc_return(&vif->hash.cache.seq);
 138                        found = true;
 139                        break;
 140                }
 141        }
 142
 143        rcu_read_unlock();
 144
 145        if (!found)
 146                val = xenvif_new_hash(vif, data, len);
 147
 148        return val;
 149}
 150
 151void xenvif_set_skb_hash(struct xenvif *vif, struct sk_buff *skb)
 152{
 153        struct flow_keys flow;
 154        u32 hash = 0;
 155        enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 156        u32 flags = vif->hash.flags;
 157        bool has_tcp_hdr;
 158
 159        /* Quick rejection test: If the network protocol doesn't
 160         * correspond to any enabled hash type then there's no point
 161         * in parsing the packet header.
 162         */
 163        switch (skb->protocol) {
 164        case htons(ETH_P_IP):
 165                if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
 166                             XEN_NETIF_CTRL_HASH_TYPE_IPV4))
 167                        break;
 168
 169                goto done;
 170
 171        case htons(ETH_P_IPV6):
 172                if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP |
 173                             XEN_NETIF_CTRL_HASH_TYPE_IPV6))
 174                        break;
 175
 176                goto done;
 177
 178        default:
 179                goto done;
 180        }
 181
 182        memset(&flow, 0, sizeof(flow));
 183        if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
 184                goto done;
 185
 186        has_tcp_hdr = (flow.basic.ip_proto == IPPROTO_TCP) &&
 187                      !(flow.control.flags & FLOW_DIS_IS_FRAGMENT);
 188
 189        switch (skb->protocol) {
 190        case htons(ETH_P_IP):
 191                if (has_tcp_hdr &&
 192                    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)) {
 193                        u8 data[12];
 194
 195                        memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
 196                        memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
 197                        memcpy(&data[8], &flow.ports.src, 2);
 198                        memcpy(&data[10], &flow.ports.dst, 2);
 199
 200                        hash = xenvif_find_hash(vif, data, sizeof(data));
 201                        type = PKT_HASH_TYPE_L4;
 202                } else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4) {
 203                        u8 data[8];
 204
 205                        memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
 206                        memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
 207
 208                        hash = xenvif_find_hash(vif, data, sizeof(data));
 209                        type = PKT_HASH_TYPE_L3;
 210                }
 211
 212                break;
 213
 214        case htons(ETH_P_IPV6):
 215                if (has_tcp_hdr &&
 216                    (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)) {
 217                        u8 data[36];
 218
 219                        memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
 220                        memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
 221                        memcpy(&data[32], &flow.ports.src, 2);
 222                        memcpy(&data[34], &flow.ports.dst, 2);
 223
 224                        hash = xenvif_find_hash(vif, data, sizeof(data));
 225                        type = PKT_HASH_TYPE_L4;
 226                } else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6) {
 227                        u8 data[32];
 228
 229                        memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
 230                        memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
 231
 232                        hash = xenvif_find_hash(vif, data, sizeof(data));
 233                        type = PKT_HASH_TYPE_L3;
 234                }
 235
 236                break;
 237        }
 238
 239done:
 240        if (type == PKT_HASH_TYPE_NONE)
 241                skb_clear_hash(skb);
 242        else
 243                __skb_set_sw_hash(skb, hash, type == PKT_HASH_TYPE_L4);
 244}
 245
 246u32 xenvif_set_hash_alg(struct xenvif *vif, u32 alg)
 247{
 248        switch (alg) {
 249        case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
 250        case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
 251                break;
 252
 253        default:
 254                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 255        }
 256
 257        vif->hash.alg = alg;
 258
 259        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 260}
 261
 262u32 xenvif_get_hash_flags(struct xenvif *vif, u32 *flags)
 263{
 264        if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 265                return XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
 266
 267        *flags = XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
 268                 XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
 269                 XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
 270                 XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
 271
 272        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 273}
 274
 275u32 xenvif_set_hash_flags(struct xenvif *vif, u32 flags)
 276{
 277        if (flags & ~(XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
 278                      XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
 279                      XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
 280                      XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP))
 281                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 282
 283        if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 284                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 285
 286        vif->hash.flags = flags;
 287
 288        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 289}
 290
 291u32 xenvif_set_hash_key(struct xenvif *vif, u32 gref, u32 len)
 292{
 293        u8 *key = vif->hash.key;
 294        struct gnttab_copy copy_op = {
 295                .source.u.ref = gref,
 296                .source.domid = vif->domid,
 297                .dest.u.gmfn = virt_to_gfn(key),
 298                .dest.domid = DOMID_SELF,
 299                .dest.offset = xen_offset_in_page(key),
 300                .len = len,
 301                .flags = GNTCOPY_source_gref
 302        };
 303
 304        if (len > XEN_NETBK_MAX_HASH_KEY_SIZE)
 305                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 306
 307        if (copy_op.len != 0) {
 308                gnttab_batch_copy(&copy_op, 1);
 309
 310                if (copy_op.status != GNTST_okay)
 311                        return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 312        }
 313
 314        /* Clear any remaining key octets */
 315        if (len < XEN_NETBK_MAX_HASH_KEY_SIZE)
 316                memset(key + len, 0, XEN_NETBK_MAX_HASH_KEY_SIZE - len);
 317
 318        xenvif_flush_hash(vif);
 319
 320        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 321}
 322
 323u32 xenvif_set_hash_mapping_size(struct xenvif *vif, u32 size)
 324{
 325        if (size > XEN_NETBK_MAX_HASH_MAPPING_SIZE)
 326                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 327
 328        vif->hash.size = size;
 329        memset(vif->hash.mapping[vif->hash.mapping_sel], 0,
 330               sizeof(u32) * size);
 331
 332        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 333}
 334
 335u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,
 336                            u32 off)
 337{
 338        u32 *mapping = vif->hash.mapping[!vif->hash.mapping_sel];
 339        unsigned int nr = 1;
 340        struct gnttab_copy copy_op[2] = {{
 341                .source.u.ref = gref,
 342                .source.domid = vif->domid,
 343                .dest.domid = DOMID_SELF,
 344                .len = len * sizeof(*mapping),
 345                .flags = GNTCOPY_source_gref
 346        }};
 347
 348        if ((off + len < off) || (off + len > vif->hash.size) ||
 349            len > XEN_PAGE_SIZE / sizeof(*mapping))
 350                return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 351
 352        copy_op[0].dest.u.gmfn = virt_to_gfn(mapping + off);
 353        copy_op[0].dest.offset = xen_offset_in_page(mapping + off);
 354        if (copy_op[0].dest.offset + copy_op[0].len > XEN_PAGE_SIZE) {
 355                copy_op[1] = copy_op[0];
 356                copy_op[1].source.offset = XEN_PAGE_SIZE - copy_op[0].dest.offset;
 357                copy_op[1].dest.u.gmfn = virt_to_gfn(mapping + off + len);
 358                copy_op[1].dest.offset = 0;
 359                copy_op[1].len = copy_op[0].len - copy_op[1].source.offset;
 360                copy_op[0].len = copy_op[1].source.offset;
 361                nr = 2;
 362        }
 363
 364        memcpy(mapping, vif->hash.mapping[vif->hash.mapping_sel],
 365               vif->hash.size * sizeof(*mapping));
 366
 367        if (copy_op[0].len != 0) {
 368                gnttab_batch_copy(copy_op, nr);
 369
 370                if (copy_op[0].status != GNTST_okay ||
 371                    copy_op[nr - 1].status != GNTST_okay)
 372                        return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 373        }
 374
 375        while (len-- != 0)
 376                if (mapping[off++] >= vif->num_queues)
 377                        return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
 378
 379        vif->hash.mapping_sel = !vif->hash.mapping_sel;
 380
 381        return XEN_NETIF_CTRL_STATUS_SUCCESS;
 382}
 383
 384#ifdef CONFIG_DEBUG_FS
 385void xenvif_dump_hash_info(struct xenvif *vif, struct seq_file *m)
 386{
 387        unsigned int i;
 388
 389        switch (vif->hash.alg) {
 390        case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
 391                seq_puts(m, "Hash Algorithm: TOEPLITZ\n");
 392                break;
 393
 394        case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
 395                seq_puts(m, "Hash Algorithm: NONE\n");
 396                fallthrough;
 397        default:
 398                return;
 399        }
 400
 401        if (vif->hash.flags) {
 402                seq_puts(m, "\nHash Flags:\n");
 403
 404                if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4)
 405                        seq_puts(m, "- IPv4\n");
 406                if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)
 407                        seq_puts(m, "- IPv4 + TCP\n");
 408                if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6)
 409                        seq_puts(m, "- IPv6\n");
 410                if (vif->hash.flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)
 411                        seq_puts(m, "- IPv6 + TCP\n");
 412        }
 413
 414        seq_puts(m, "\nHash Key:\n");
 415
 416        for (i = 0; i < XEN_NETBK_MAX_HASH_KEY_SIZE; ) {
 417                unsigned int j, n;
 418
 419                n = 8;
 420                if (i + n >= XEN_NETBK_MAX_HASH_KEY_SIZE)
 421                        n = XEN_NETBK_MAX_HASH_KEY_SIZE - i;
 422
 423                seq_printf(m, "[%2u - %2u]: ", i, i + n - 1);
 424
 425                for (j = 0; j < n; j++, i++)
 426                        seq_printf(m, "%02x ", vif->hash.key[i]);
 427
 428                seq_puts(m, "\n");
 429        }
 430
 431        if (vif->hash.size != 0) {
 432                const u32 *mapping = vif->hash.mapping[vif->hash.mapping_sel];
 433
 434                seq_puts(m, "\nHash Mapping:\n");
 435
 436                for (i = 0; i < vif->hash.size; ) {
 437                        unsigned int j, n;
 438
 439                        n = 8;
 440                        if (i + n >= vif->hash.size)
 441                                n = vif->hash.size - i;
 442
 443                        seq_printf(m, "[%4u - %4u]: ", i, i + n - 1);
 444
 445                        for (j = 0; j < n; j++, i++)
 446                                seq_printf(m, "%4u ", mapping[i]);
 447
 448                        seq_puts(m, "\n");
 449                }
 450        }
 451}
 452#endif /* CONFIG_DEBUG_FS */
 453
 454void xenvif_init_hash(struct xenvif *vif)
 455{
 456        if (xenvif_hash_cache_size == 0)
 457                return;
 458
 459        BUG_ON(vif->hash.cache.count);
 460
 461        spin_lock_init(&vif->hash.cache.lock);
 462        INIT_LIST_HEAD(&vif->hash.cache.list);
 463}
 464
 465void xenvif_deinit_hash(struct xenvif *vif)
 466{
 467        xenvif_flush_hash(vif);
 468}
 469