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