datapath/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/ipv6.h>
  45 #include <net/ndisc.h>
  46
  47 #include "vlan.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_OFFSET 13
  63 #define TCP_FLAG_MASK 0x3f
  64
  65 void ovs_flow_used(struct sw_flow *flow, struct sk_buff *skb)
  66 {
  67         u8 tcp_flags = 0;
  68
  69         if ((flow->key.eth.type == htons(ETH_P_IP) ||
  70              flow->key.eth.type == htons(ETH_P_IPV6)) &&
  71             flow->key.ip.proto == IPPROTO_TCP &&
  72             likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
  73                 u8 *tcp = (u8 *)tcp_hdr(skb);
  74                 tcp_flags = *(tcp + TCP_FLAGS_OFFSET) & TCP_FLAG_MASK;
  75         }
  76
  77         spin_lock(&flow->lock);
  78         flow->used = jiffies;
  79         flow->packet_count++;
  80         flow->byte_count += skb->len;
  81         flow->tcp_flags |= tcp_flags;
  82         spin_unlock(&flow->lock);
  83 }
  84
  85 static int check_header(struct sk_buff *skb, int len)
  86 {
  87         if (unlikely(skb->len < len))
  88                 return -EINVAL;
  89         if (unlikely(!pskb_may_pull(skb, len)))
  90                 return -ENOMEM;
  91         return 0;
  92 }
  93
  94 static bool arphdr_ok(struct sk_buff *skb)
  95 {
  96         return pskb_may_pull(skb, skb_network_offset(skb) +
  97                                   sizeof(struct arp_eth_header));
  98 }
  99
 100 static int check_iphdr(struct sk_buff *skb)
 101 {
 102         unsigned int nh_ofs = skb_network_offset(skb);
 103         unsigned int ip_len;
 104         int err;
 105
 106         err = check_header(skb, nh_ofs + sizeof(struct iphdr));
 107         if (unlikely(err))
 108                 return err;
 109
 110         ip_len = ip_hdrlen(skb);
 111         if (unlikely(ip_len < sizeof(struct iphdr) ||
 112                      skb->len < nh_ofs + ip_len))
 113                 return -EINVAL;
 114
 115         skb_set_transport_header(skb, nh_ofs + ip_len);
 116         return 0;
 117 }
 118
 119 static bool tcphdr_ok(struct sk_buff *skb)
 120 {
 121         int th_ofs = skb_transport_offset(skb);
 122         int tcp_len;
 123
 124         if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
 125                 return false;
 126
 127         tcp_len = tcp_hdrlen(skb);
 128         if (unlikely(tcp_len < sizeof(struct tcphdr) ||
 129                      skb->len < th_ofs + tcp_len))
 130                 return false;
 131
 132         return true;
 133 }
 134
 135 static bool udphdr_ok(struct sk_buff *skb)
 136 {
 137         return pskb_may_pull(skb, skb_transport_offset(skb) +
 138                                   sizeof(struct udphdr));
 139 }
 140
 141 static bool sctphdr_ok(struct sk_buff *skb)
 142 {
 143         return pskb_may_pull(skb, skb_transport_offset(skb) +
 144                                   sizeof(struct sctphdr));
 145 }
 146
 147 static bool icmphdr_ok(struct sk_buff *skb)
 148 {
 149         return pskb_may_pull(skb, skb_transport_offset(skb) +
 150                                   sizeof(struct icmphdr));
 151 }
 152
 153 static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
 154 {
 155         unsigned int nh_ofs = skb_network_offset(skb);
 156         unsigned int nh_len;
 157         int payload_ofs;
 158         struct ipv6hdr *nh;
 159         uint8_t nexthdr;
 160         __be16 frag_off;
 161         int err;
 162
 163         err = check_header(skb, nh_ofs + sizeof(*nh));
 164         if (unlikely(err))
 165                 return err;
 166
 167         nh = ipv6_hdr(skb);
 168         nexthdr = nh->nexthdr;
 169         payload_ofs = (u8 *)(nh + 1) - skb->data;
 170
 171         key->ip.proto = NEXTHDR_NONE;
 172         key->ip.tos = ipv6_get_dsfield(nh);
 173         key->ip.ttl = nh->hop_limit;
 174         key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
 175         key->ipv6.addr.src = nh->saddr;
 176         key->ipv6.addr.dst = nh->daddr;
 177
 178         payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
 179         if (unlikely(payload_ofs < 0))
 180                 return -EINVAL;
 181
 182         if (frag_off) {
 183                 if (frag_off & htons(~0x7))
 184                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 185                 else
 186                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 187         }
 188
 189         nh_len = payload_ofs - nh_ofs;
 190         skb_set_transport_header(skb, nh_ofs + nh_len);
 191         key->ip.proto = nexthdr;
 192         return nh_len;
 193 }
 194
 195 static bool icmp6hdr_ok(struct sk_buff *skb)
 196 {
 197         return pskb_may_pull(skb, skb_transport_offset(skb) +
 198                                   sizeof(struct icmp6hdr));
 199 }
 200
 201 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
 202 {
 203         struct qtag_prefix {
 204                 __be16 eth_type; /* ETH_P_8021Q */
 205                 __be16 tci;
 206         };
 207         struct qtag_prefix *qp;
 208
 209         if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
 210                 return 0;
 211
 212         if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
 213                                          sizeof(__be16))))
 214                 return -ENOMEM;
 215
 216         qp = (struct qtag_prefix *) skb->data;
 217         key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
 218         __skb_pull(skb, sizeof(struct qtag_prefix));
 219
 220         return 0;
 221 }
 222
 223 static __be16 parse_ethertype(struct sk_buff *skb)
 224 {
 225         struct llc_snap_hdr {
 226                 u8  dsap;  /* Always 0xAA */
 227                 u8  ssap;  /* Always 0xAA */
 228                 u8  ctrl;
 229                 u8  oui[3];
 230                 __be16 ethertype;
 231         };
 232         struct llc_snap_hdr *llc;
 233         __be16 proto;
 234
 235         proto = *(__be16 *) skb->data;
 236         __skb_pull(skb, sizeof(__be16));
 237
 238         if (ntohs(proto) >= ETH_P_802_3_MIN)
 239                 return proto;
 240
 241         if (skb->len < sizeof(struct llc_snap_hdr))
 242                 return htons(ETH_P_802_2);
 243
 244         if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
 245                 return htons(0);
 246
 247         llc = (struct llc_snap_hdr *) skb->data;
 248         if (llc->dsap != LLC_SAP_SNAP ||
 249             llc->ssap != LLC_SAP_SNAP ||
 250             (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
 251                 return htons(ETH_P_802_2);
 252
 253         __skb_pull(skb, sizeof(struct llc_snap_hdr));
 254
 255         if (ntohs(llc->ethertype) >= ETH_P_802_3_MIN)
 256                 return llc->ethertype;
 257
 258         return htons(ETH_P_802_2);
 259 }
 260
 261 static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
 262                         int nh_len)
 263 {
 264         struct icmp6hdr *icmp = icmp6_hdr(skb);
 265
 266         /* The ICMPv6 type and code fields use the 16-bit transport port
 267          * fields, so we need to store them in 16-bit network byte order.
 268          */
 269         key->ipv6.tp.src = htons(icmp->icmp6_type);
 270         key->ipv6.tp.dst = htons(icmp->icmp6_code);
 271
 272         if (icmp->icmp6_code == 0 &&
 273             (icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
 274              icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
 275                 int icmp_len = skb->len - skb_transport_offset(skb);
 276                 struct nd_msg *nd;
 277                 int offset;
 278
 279                 /* In order to process neighbor discovery options, we need the
 280                  * entire packet.
 281                  */
 282                 if (unlikely(icmp_len < sizeof(*nd)))
 283                         return 0;
 284
 285                 if (unlikely(skb_linearize(skb)))
 286                         return -ENOMEM;
 287
 288                 nd = (struct nd_msg *)skb_transport_header(skb);
 289                 key->ipv6.nd.target = nd->target;
 290
 291                 icmp_len -= sizeof(*nd);
 292                 offset = 0;
 293                 while (icmp_len >= 8) {
 294                         struct nd_opt_hdr *nd_opt =
 295                                  (struct nd_opt_hdr *)(nd->opt + offset);
 296                         int opt_len = nd_opt->nd_opt_len * 8;
 297
 298                         if (unlikely(!opt_len || opt_len > icmp_len))
 299                                 return 0;
 300
 301                         /* Store the link layer address if the appropriate
 302                          * option is provided.  It is considered an error if
 303                          * the same link layer option is specified twice.
 304                          */
 305                         if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
 306                             && opt_len == 8) {
 307                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
 308                                         goto invalid;
 309                                 memcpy(key->ipv6.nd.sll,
 310                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 311                         } else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
 312                                    && opt_len == 8) {
 313                                 if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
 314                                         goto invalid;
 315                                 memcpy(key->ipv6.nd.tll,
 316                                     &nd->opt[offset+sizeof(*nd_opt)], ETH_ALEN);
 317                         }
 318
 319                         icmp_len -= opt_len;
 320                         offset += opt_len;
 321                 }
 322         }
 323
 324         return 0;
 325
 326 invalid:
 327         memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
 328         memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
 329         memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
 330
 331         return 0;
 332 }
 333
 334 /**
 335  * ovs_flow_extract - extracts a flow key from an Ethernet frame.
 336  * @skb: sk_buff that contains the frame, with skb->data pointing to the
 337  * Ethernet header
 338  * @in_port: port number on which @skb was received.
 339  * @key: output flow key
 340  *
 341  * The caller must ensure that skb->len >= ETH_HLEN.
 342  *
 343  * Returns 0 if successful, otherwise a negative errno value.
 344  *
 345  * Initializes @skb header pointers as follows:
 346  *
 347  *    - skb->mac_header: the Ethernet header.
 348  *
 349  *    - skb->network_header: just past the Ethernet header, or just past the
 350  *      VLAN header, to the first byte of the Ethernet payload.
 351  *
 352  *    - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
 353  *      on output, then just past the IP header, if one is present and
 354  *      of a correct length, otherwise the same as skb->network_header.
 355  *      For other key->eth.type values it is left untouched.
 356  */
 357 int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 358 {
 359         int error;
 360         struct ethhdr *eth;
 361
 362         memset(key, 0, sizeof(*key));
 363
 364         key->phy.priority = skb->priority;
 365         if (OVS_CB(skb)->tun_key)
 366                 memcpy(&key->tun_key, OVS_CB(skb)->tun_key, sizeof(key->tun_key));
 367         key->phy.in_port = in_port;
 368         key->phy.skb_mark = skb->mark;
 369
 370         skb_reset_mac_header(skb);
 371
 372         /* Link layer.  We are guaranteed to have at least the 14 byte Ethernet
 373          * header in the linear data area.
 374          */
 375         eth = eth_hdr(skb);
 376         memcpy(key->eth.src, eth->h_source, ETH_ALEN);
 377         memcpy(key->eth.dst, eth->h_dest, ETH_ALEN);
 378
 379         __skb_pull(skb, 2 * ETH_ALEN);
 380         /* We are going to push all headers that we pull, so no need to
 381          * update skb->csum here. */
 382
 383         if (vlan_tx_tag_present(skb))
 384                 key->eth.tci = htons(vlan_get_tci(skb));
 385         else if (eth->h_proto == htons(ETH_P_8021Q))
 386                 if (unlikely(parse_vlan(skb, key)))
 387                         return -ENOMEM;
 388
 389         key->eth.type = parse_ethertype(skb);
 390         if (unlikely(key->eth.type == htons(0)))
 391                 return -ENOMEM;
 392
 393         skb_reset_network_header(skb);
 394         __skb_push(skb, skb->data - skb_mac_header(skb));
 395
 396         /* Network layer. */
 397         if (key->eth.type == htons(ETH_P_IP)) {
 398                 struct iphdr *nh;
 399                 __be16 offset;
 400
 401                 error = check_iphdr(skb);
 402                 if (unlikely(error)) {
 403                         if (error == -EINVAL) {
 404                                 skb->transport_header = skb->network_header;
 405                                 error = 0;
 406                         }
 407                         return error;
 408                 }
 409
 410                 nh = ip_hdr(skb);
 411                 key->ipv4.addr.src = nh->saddr;
 412                 key->ipv4.addr.dst = nh->daddr;
 413
 414                 key->ip.proto = nh->protocol;
 415                 key->ip.tos = nh->tos;
 416                 key->ip.ttl = nh->ttl;
 417
 418                 offset = nh->frag_off & htons(IP_OFFSET);
 419                 if (offset) {
 420                         key->ip.frag = OVS_FRAG_TYPE_LATER;
 421                         return 0;
 422                 }
 423                 if (nh->frag_off & htons(IP_MF) ||
 424                          skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 425                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 426
 427                 /* Transport layer. */
 428                 if (key->ip.proto == IPPROTO_TCP) {
 429                         if (tcphdr_ok(skb)) {
 430                                 struct tcphdr *tcp = tcp_hdr(skb);
 431                                 key->ipv4.tp.src = tcp->source;
 432                                 key->ipv4.tp.dst = tcp->dest;
 433                         }
 434                 } else if (key->ip.proto == IPPROTO_UDP) {
 435                         if (udphdr_ok(skb)) {
 436                                 struct udphdr *udp = udp_hdr(skb);
 437                                 key->ipv4.tp.src = udp->source;
 438                                 key->ipv4.tp.dst = udp->dest;
 439                         }
 440                 } else if (key->ip.proto == IPPROTO_SCTP) {
 441                         if (sctphdr_ok(skb)) {
 442                                 struct sctphdr *sctp = sctp_hdr(skb);
 443                                 key->ipv4.tp.src = sctp->source;
 444                                 key->ipv4.tp.dst = sctp->dest;
 445                         }
 446                 } else if (key->ip.proto == IPPROTO_ICMP) {
 447                         if (icmphdr_ok(skb)) {
 448                                 struct icmphdr *icmp = icmp_hdr(skb);
 449                                 /* The ICMP type and code fields use the 16-bit
 450                                  * transport port fields, so we need to store
 451                                  * them in 16-bit network byte order. */
 452                                 key->ipv4.tp.src = htons(icmp->type);
 453                                 key->ipv4.tp.dst = htons(icmp->code);
 454                         }
 455                 }
 456
 457         } else if ((key->eth.type == htons(ETH_P_ARP) ||
 458                    key->eth.type == htons(ETH_P_RARP)) && arphdr_ok(skb)) {
 459                 struct arp_eth_header *arp;
 460
 461                 arp = (struct arp_eth_header *)skb_network_header(skb);
 462
 463                 if (arp->ar_hrd == htons(ARPHRD_ETHER)
 464                                 && arp->ar_pro == htons(ETH_P_IP)
 465                                 && arp->ar_hln == ETH_ALEN
 466                                 && arp->ar_pln == 4) {
 467
 468                         /* We only match on the lower 8 bits of the opcode. */
 469                         if (ntohs(arp->ar_op) <= 0xff)
 470                                 key->ip.proto = ntohs(arp->ar_op);
 471                         memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
 472                         memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
 473                         memcpy(key->ipv4.arp.sha, arp->ar_sha, ETH_ALEN);
 474                         memcpy(key->ipv4.arp.tha, arp->ar_tha, ETH_ALEN);
 475                 }
 476         } else if (key->eth.type == htons(ETH_P_IPV6)) {
 477                 int nh_len;             /* IPv6 Header + Extensions */
 478
 479                 nh_len = parse_ipv6hdr(skb, key);
 480                 if (unlikely(nh_len < 0)) {
 481                         if (nh_len == -EINVAL) {
 482                                 skb->transport_header = skb->network_header;
 483                                 error = 0;
 484                         } else {
 485                                 error = nh_len;
 486                         }
 487                         return error;
 488                 }
 489
 490                 if (key->ip.frag == OVS_FRAG_TYPE_LATER)
 491                         return 0;
 492                 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 493                         key->ip.frag = OVS_FRAG_TYPE_FIRST;
 494
 495                 /* Transport layer. */
 496                 if (key->ip.proto == NEXTHDR_TCP) {
 497                         if (tcphdr_ok(skb)) {
 498                                 struct tcphdr *tcp = tcp_hdr(skb);
 499                                 key->ipv6.tp.src = tcp->source;
 500                                 key->ipv6.tp.dst = tcp->dest;
 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 }