Pileus Git - ~andy/linux/blob - net/openvswitch/flow.c

   1 /*
   2  * Copyright (c) 2007-2013 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #include "flow.h"
  20 #include "datapath.h"
  21 #include <linux/uaccess.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/etherdevice.h>
  24 #include <linux/if_ether.h>
  25 #include <linux/if_vlan.h>
  26 #include <net/llc_pdu.h>
  27 #include <linux/kernel.h>
  28 #include <linux/jhash.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/llc.h>
  31 #include <linux/module.h>
  32 #include <linux/in.h>
  33 #include <linux/rcupdate.h>
  34 #include <linux/if_arp.h>
  35 #include <linux/ip.h>
  36 #include <linux/ipv6.h>
  37 #include <linux/sctp.h>
  38 #include <linux/smp.h>
  39 #include <linux/tcp.h>
  40 #include <linux/udp.h>
  41 #include <linux/icmp.h>
  42 #include <linux/icmpv6.h>
  43 #include <linux/rculist.h>
  44 #include <net/ip.h>
  45 #include <net/ip_tunnels.h>
  46 #include <net/ipv6.h>
  47 #include <net/ndisc.h>
  48
  49 u64 ovs_flow_used_time(unsigned long flow_jiffies)
  50 {
  51         struct timespec cur_ts;
  52         u64 cur_ms, idle_ms;
  53
  54         ktime_get_ts(&cur_ts);
  55         idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);
  56         cur_ms = (u64)cur_ts.tv_sec * MSEC_PER_SEC +
  57                  cur_ts.tv_nsec / NSEC_PER_MSEC;
  58
  59         return cur_ms - idle_ms;
  60 }
  61
  62 #define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))
  63
  64 void ovs_flow_stats_update(struct sw_flow *flow, struct sk_buff *skb)
  65 {
  66         struct flow_stats *stats;
  67         __be16 tcp_flags = 0;
  68
  69         if (!flow->stats.is_percpu)
  70                 stats = flow->stats.stat;
  71         else
  72                 stats = this_cpu_ptr(flow->stats.cpu_stats);
  73
  74         if ((flow->key.eth.type == htons(ETH_P_IP) ||
  75              flow->key.eth.type == htons(ETH_P_IPV6)) &&
  76             flow->key.ip.frag != OVS_FRAG_TYPE_LATER &&
  77             flow->key.ip.proto == IPPROTO_TCP &&
  78             likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
  79                 tcp_flags = TCP_FLAGS_BE16(tcp_hdr(skb));
  80         }
  81
  82         spin_lock(&stats->lock);
  83         stats->used = jiffies;
  84         stats->packet_count++;
  85         stats->byte_count += skb->len;
  86         stats->tcp_flags |= tcp_flags;
  87         spin_unlock(&stats->lock);
  88 }
  89
  90 static void stats_read(struct flow_stats *stats,
  91                        struct ovs_flow_stats *ovs_stats,
  92                        unsigned long *used, __be16 *tcp_flags)
  93 {
  94         spin_lock(&stats->lock);
  95         if (!*used || time_after(stats->used, *used))
  96                 *used = stats->used;
  97         *tcp_flags |= stats->tcp_flags;
  98         ovs_stats->n_packets += stats->packet_count;
  99         ovs_stats->n_bytes += stats->byte_count;
 100         spin_unlock(&stats->lock);
 101 }
 102
 103 void ovs_flow_stats_get(struct sw_flow *flow, struct ovs_flow_stats *ovs_stats,
 104                         unsigned long *used, __be16 *tcp_flags)
 105 {
 106         int cpu;
 107
 108         *used = 0;
 109         *tcp_flags = 0;
 110         memset(ovs_stats, 0, sizeof(*ovs_stats));
 111
 112         local_bh_disable();
 113         if (!flow->stats.is_percpu) {
 114                 stats_read(flow->stats.stat, ovs_stats, used, tcp_flags);
 115         } else {
 116                 for_each_possible_cpu(cpu) {
 117                         struct flow_stats *stats;
 118
 119                         stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
 120                         stats_read(stats, ovs_stats, used, tcp_flags);
 121                 }
 122         }
 123         local_bh_enable();
 124 }
 125
 126 static void stats_reset(struct flow_stats *stats)
 127 {
 128         spin_lock(&stats->lock);
 129         stats->used = 0;
 130         stats->packet_count = 0;
 131         stats->byte_count = 0;
 132         stats->tcp_flags = 0;
 133         spin_unlock(&stats->lock);
 134 }
 135
 136 void ovs_flow_stats_clear(struct sw_flow *flow)
 137 {
 138         int cpu;
 139
 140         local_bh_disable();
 141         if (!flow->stats.is_percpu) {
 142                 stats_reset(flow->stats.stat);
 143         } else {
 144                 for_each_possible_cpu(cpu) {
 145                         stats_reset(per_cpu_ptr(flow->stats.cpu_stats, cpu));
 146                 }
 147         }
 148         local_bh_enable();
 149 }
 150
 151 static int check_header(struct sk_buff *skb, int len)
 152 {
 153         if (unlikely(skb->len < len))
 154                 return -EINVAL;
 155         if (unlikely(!pskb_may_pull(skb, len)))
 156                 return -ENOMEM;
 157         return 0;
 158 }
 159
 160 static bool arphdr_ok(struct sk_buff *skb)
 161 {
 162         return pskb_may_pull(skb, skb_network_offset(skb) +
 163                                   sizeof(struct arp_eth_header));
 164 }
 165
 166 static int check_iphdr(struct sk_buff *skb)
 167 {
 168         unsigned int nh_ofs = skb_network_offset(skb);
 169         unsigned int ip_len;
 170         int err;
 171
 172         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 173         if (unlikely(err))
 174                 return err;
 175
 176         ip_len = ip_hdrlen(skb);
 177         if (unlikely(ip_len < sizeof(struct iphdr) ||
 178                      skb->len < nh_ofs + ip_len))
 179                 return -EINVAL;
 180
 181         skb_set_transport_header(skb, nh_ofs + ip_len);
 182         return 0;
 183 }
 184
 185 static bool tcphdr_ok(struct sk_buff *skb)
 186 {
 187         int th_ofs = skb_transport_offset(skb);
 188         int tcp_len;
 189
 190         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 191                 return false;
 192
 193         tcp_len = tcp_hdrlen(skb);
 194         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 195                      skb->len < th_ofs + tcp_len))
 196                 return false;
 197
 198         return true;
 199 }
 200
 201 static bool udphdr_ok(struct sk_buff *skb)
 202 {
 203         return pskb_may_pull(skb, skb_transport_offset(skb) +
 204                                   sizeof(struct udphdr));
 205 }
 206
 207 static bool sctphdr_ok(struct sk_buff *skb)
 208 {
 209         return pskb_may_pull(skb, skb_transport_offset(skb) +
 210                                   sizeof(struct sctphdr));
 211 }
 212
 213 static bool icmphdr_ok(struct sk_buff *skb)
 214 {
 215         return pskb_may_pull(skb, skb_transport_offset(skb) +
 216                                   sizeof(struct icmphdr));
 217 }
 218
 219 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 220 {
 221         unsigned int nh_ofs = skb_network_offset(skb);
 222         unsigned int nh_len;
 223         int payload_ofs;
 224         struct ipv6hdr *nh;
 225         uint8_t nexthdr;
 226         __be16 frag_off;
 227         int err;
 228
 229         err = check_header(skb, nh_ofs + sizeof(*nh));
 230         if (unlikely(err))
 231                 return err;
 232
 233         nh = ipv6_hdr(skb);
 234         nexthdr = nh->nexthdr;
 235         payload_ofs = (u8 *)(nh + 1) - skb->data;
 236
 237         key->ip.proto = NEXTHDR_NONE;
 238         key->ip.tos = ipv6_get_dsfield(nh);
 239         key->ip.ttl = nh->hop_limit;
 240         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 241         key->ipv6.addr.src = nh->saddr;
 242         key->ipv6.addr.dst = nh->daddr;
 243
 244         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 245         if (unlikely(payload_ofs < 0))
 246                 return -EINVAL;
 247
 248         if (frag_off) {
 249                 if (frag_off & htons(~0x7))
 250                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 251                 else
 252                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 253         }
 254
 255         nh_len = payload_ofs - nh_ofs;
 256         skb_set_transport_header(skb, nh_ofs + nh_len);
 257         key->ip.proto = nexthdr;
 258         return nh_len;
 259 }
 260
 261 static bool icmp6hdr_ok(struct sk_buff *skb)
 262 {
 263         return pskb_may_pull(skb, skb_transport_offset(skb) +
 264                                   sizeof(struct icmp6hdr));
 265 }
 266
 267 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 268 {
 269         struct qtag_prefix {
 270                 __be16 eth_type; /* ETH_P_8021Q */
 271                 __be16 tci;
 272         };
 273         struct qtag_prefix *qp;
 274
 275         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 276                 return 0;
 277
 278         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 279                                          sizeof(__be16))))
 280                 return -ENOMEM;
 281
 282         qp = (struct qtag_prefix *) skb->data;
 283         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 284         __skb_pull(skb, sizeof(struct qtag_prefix));
 285
 286         return 0;
 287 }
 288
 289 static __be16 parse_ethertype(struct sk_buff *skb)
 290 {
 291         struct llc_snap_hdr {
 292                 u8  dsap;  /* Always 0xAA */
 293                 u8  ssap;  /* Always 0xAA */
 294                 u8  ctrl;
 295                 u8  oui[3];
 296                 __be16 ethertype;
 297         };
 298         struct llc_snap_hdr *llc;
 299         __be16 proto;
 300
 301         proto = *(__be16 *) skb->data;
 302         __skb_pull(skb, sizeof(__be16));
 303
 304         if (ntohs(proto) >= ETH_P_802_3_MIN)
 305                 return proto;
 306
 307         if (skb->len < sizeof(struct llc_snap_hdr))
 308                 return htons(ETH_P_802_2);
 309
 310         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 311                 return htons(0);
 312
 313         llc = (struct llc_snap_hdr *) skb->data;
 314         if (llc->dsap != LLC_SAP_SNAP ||
 315             llc->ssap != LLC_SAP_SNAP ||
 316             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 317                 return htons(ETH_P_802_2);
 318
 319         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 320
 321         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 322                 return llc->ethertype;
 323
 324         return htons(ETH_P_802_2);
 325 }
 326
 327 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 328                         int nh_len)
 329 {
 330         struct icmp6hdr *icmp = icmp6_hdr(skb);
 331
 332         /* The ICMPv6 type and code fields use the 16-bit transport port
 333          * fields, so we need to store them in 16-bit network byte order.
 334          */
 335         key->ipv6.tp.src = htons(icmp->icmp6_type);
 336         key->ipv6.tp.dst = htons(icmp->icmp6_code);
 337
 338         if (icmp->icmp6_code == 0 &&
 339             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 340              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 341                 int icmp_len = skb->len - skb_transport_offset(skb);
 342                 struct nd_msg *nd;
 343                 int offset;
 344
 345                 /* In order to process neighbor discovery options, we need the
 346                  * entire packet.
 347                  */
 348                 if (unlikely(icmp_len < sizeof(*nd)))
 349                         return 0;
 350
 351                 if (unlikely(skb_linearize(skb)))
 352                         return -ENOMEM;
 353
 354                 nd = (struct nd_msg *)skb_transport_header(skb);
 355                 key->ipv6.nd.target = nd->target;
 356
 357                 icmp_len -= sizeof(*nd);
 358                 offset = 0;
 359                 while (icmp_len >= 8) {
 360                         struct nd_opt_hdr *nd_opt =
 361                                  (struct nd_opt_hdr *)(nd->opt + offset);
 362                         int opt_len = nd_opt->nd_opt_len * 8;
 363
 364                         if (unlikely(!opt_len || opt_len > icmp_len))
 365                                 return 0;
 366
 367                         /* Store the link layer address if the appropriate
 368                          * option is provided.  It is considered an error if
 369                          * the same link layer option is specified twice.
 370                          */
 371                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 372                             && opt_len == 8) {
 373                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 374                                         goto invalid;
 375                                 memcpy(key->ipv6.nd.sll,
 376                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 377                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 378                                    && opt_len == 8) {
 379                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 380                                         goto invalid;
 381                                 memcpy(key->ipv6.nd.tll,
 382                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 383                         }
 384
 385                         icmp_len -= opt_len;
 386                         offset += opt_len;
 387                 }
 388         }
 389
 390         return 0;
 391
 392 invalid:
 393         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 394         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 395         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 396
 397         return 0;
 398 }
 399
 400 /**
 401  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 402  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 403  * Ethernet header
 404  * @in_port: port number on which @skb was received.
 405  * @key: output flow key
 406  *
 407  * The caller must ensure that skb->len >= ETH_HLEN.
 408  *
 409  * Returns 0 if successful, otherwise a negative errno value.
 410  *
 411  * Initializes @skb header pointers as follows:
 412  *
 413  *    - skb->mac_header: the Ethernet header.
 414  *
 415  *    - skb->network_header: just past the Ethernet header, or just past the
 416  *      VLAN header, to the first byte of the Ethernet payload.
 417  *
 418  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 419  *      on output, then just past the IP header, if one is present and
 420  *      of a correct length, otherwise the same as skb->network_header.
 421  *      For other key->eth.type values it is left untouched.
 422  */
 423 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 424 {
 425         int error;
 426         struct ethhdr *eth;
 427
 428         memset(key, 0, sizeof(*key));
 429
 430         key->phy.priority = skb->priority;
 431         if (OVS_CB(skb)->tun_key)
 432                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 433         key->phy.in_port = in_port;
 434         key->phy.skb_mark = skb->mark;
 435
 436         skb_reset_mac_header(skb);
 437
 438         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 439          * header in the linear data area.
 440          */
 441         eth = eth_hdr(skb);
 442         memcpy(key->eth.src, eth->h_source, ETH_ALEN);
 443         memcpy(key->eth.dst, eth->h_dest, ETH_ALEN);
 444
 445         __skb_pull(skb, 2 * ETH_ALEN);
 446         /* We are going to push all headers that we pull, so no need to
 447          * update skb->csum here.
 448          */
 449
 450         if (vlan_tx_tag_present(skb))
 451                 key->eth.tci = htons(skb->vlan_tci);
 452         else if (eth->h_proto == htons(ETH_P_8021Q))
 453                 if (unlikely(parse_vlan(skb, key)))
 454                         return -ENOMEM;
 455
 456         key->eth.type = parse_ethertype(skb);
 457         if (unlikely(key->eth.type == htons(0)))
 458                 return -ENOMEM;
 459
 460         skb_reset_network_header(skb);
 461         __skb_push(skb, skb->data - skb_mac_header(skb));
 462
 463         /* Network layer. */
 464         if (key->eth.type == htons(ETH_P_IP)) {
 465                 struct iphdr *nh;
 466                 __be16 offset;
 467
 468                 error = check_iphdr(skb);
 469                 if (unlikely(error)) {
 470                         if (error == -EINVAL) {
 471                                 skb->transport_header = skb->network_header;
 472                                 error = 0;
 473                         }
 474                         return error;
 475                 }
 476
 477                 nh = ip_hdr(skb);
 478                 key->ipv4.addr.src = nh->saddr;
 479                 key->ipv4.addr.dst = nh->daddr;
 480
 481                 key->ip.proto = nh->protocol;
 482                 key->ip.tos = nh->tos;
 483                 key->ip.ttl = nh->ttl;
 484
 485                 offset = nh->frag_off & htons(IP_OFFSET);
 486                 if (offset) {
 487                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 488                         return 0;
 489                 }
 490                 if (nh->frag_off & htons(IP_MF) ||
 491                          skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 492                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 493
 494                 /* Transport layer. */
 495                 if (key->ip.proto == IPPROTO_TCP) {
 496                         if (tcphdr_ok(skb)) {
 497                                 struct tcphdr *tcp = tcp_hdr(skb);
 498                                 key->ipv4.tp.src = tcp->source;
 499                                 key->ipv4.tp.dst = tcp->dest;
 500                                 key->ipv4.tp.flags = TCP_FLAGS_BE16(tcp);
 501                         }
 502                 } else if (key->ip.proto == IPPROTO_UDP) {
 503                         if (udphdr_ok(skb)) {
 504                                 struct udphdr *udp = udp_hdr(skb);
 505                                 key->ipv4.tp.src = udp->source;
 506                                 key->ipv4.tp.dst = udp->dest;
 507                         }
 508                 } else if (key->ip.proto == IPPROTO_SCTP) {
 509                         if (sctphdr_ok(skb)) {
 510                                 struct sctphdr *sctp = sctp_hdr(skb);
 511                                 key->ipv4.tp.src = sctp->source;
 512                                 key->ipv4.tp.dst = sctp->dest;
 513                         }
 514                 } else if (key->ip.proto == IPPROTO_ICMP) {
 515                         if (icmphdr_ok(skb)) {
 516                                 struct icmphdr *icmp = icmp_hdr(skb);
 517                                 /* The ICMP type and code fields use the 16-bit
 518                                  * transport port fields, so we need to store
 519                                  * them in 16-bit network byte order. */
 520                                 key->ipv4.tp.src = htons(icmp->type);
 521                                 key->ipv4.tp.dst = htons(icmp->code);
 522                         }
 523                 }
 524
 525         } else if ((key->eth.type == htons(ETH_P_ARP) ||
 526                    key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
 527                 struct arp_eth_header *arp;
 528
 529                 arp = (struct arp_eth_header *)skb_network_header(skb);
 530
 531                 if (arp->ar_hrd == htons(ARPHRD_ETHER)
 532                                 && arp->ar_pro == htons(ETH_P_IP)
 533                                 && arp->ar_hln == ETH_ALEN
 534                                 && arp->ar_pln == 4) {
 535
 536                         /* We only match on the lower 8 bits of the opcode. */
 537                         if (ntohs(arp->ar_op) <= 0xff)
 538                                 key->ip.proto = ntohs(arp->ar_op);
 539                         memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
 540                         memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
 541                         memcpy(key->ipv4.arp.sha, arp->ar_sha, ETH_ALEN);
 542                         memcpy(key->ipv4.arp.tha, arp->ar_tha, ETH_ALEN);
 543                 }
 544         } else if (key->eth.type == htons(ETH_P_IPV6)) {
 545                 int nh_len;             /* IPv6 Header + Extensions */
 546
 547                 nh_len = parse_ipv6hdr(skb, key);
 548                 if (unlikely(nh_len < 0)) {
 549                         if (nh_len == -EINVAL) {
 550                                 skb->transport_header = skb->network_header;
 551                                 error = 0;
 552                         } else {
 553                                 error = nh_len;
 554                         }
 555                         return error;
 556                 }
 557
 558                 if (key->ip.frag == OVS_FRAG_TYPE_LATER)
 559                         return 0;
 560                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 561                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 562
 563                 /* Transport layer. */
 564                 if (key->ip.proto == NEXTHDR_TCP) {
 565                         if (tcphdr_ok(skb)) {
 566                                 struct tcphdr *tcp = tcp_hdr(skb);
 567                                 key->ipv6.tp.src = tcp->source;
 568                                 key->ipv6.tp.dst = tcp->dest;
 569                                 key->ipv6.tp.flags = TCP_FLAGS_BE16(tcp);
 570                         }
 571                 } else if (key->ip.proto == NEXTHDR_UDP) {
 572                         if (udphdr_ok(skb)) {
 573                                 struct udphdr *udp = udp_hdr(skb);
 574                                 key->ipv6.tp.src = udp->source;
 575                                 key->ipv6.tp.dst = udp->dest;
 576                         }
 577                 } else if (key->ip.proto == NEXTHDR_SCTP) {
 578                         if (sctphdr_ok(skb)) {
 579                                 struct sctphdr *sctp = sctp_hdr(skb);
 580                                 key->ipv6.tp.src = sctp->source;
 581                                 key->ipv6.tp.dst = sctp->dest;
 582                         }
 583                 } else if (key->ip.proto == NEXTHDR_ICMP) {
 584                         if (icmp6hdr_ok(skb)) {
 585                                 error = parse_icmpv6(skb, key, nh_len);
 586                                 if (error)
 587                                         return error;
 588                         }
 589                 }
 590         }
 591
 592         return 0;
 593 }