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