lib/flow.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include <config.h>
  17 #include <sys/types.h>
  18 #include "flow.h"
  19 #include <inttypes.h>
  20 #include <netinet/in.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include "byte-order.h"
  24 #include "coverage.h"
  25 #include "dpif.h"
  26 #include "dynamic-string.h"
  27 #include "hash.h"
  28 #include "ofpbuf.h"
  29 #include "openflow/openflow.h"
  30 #include "openvswitch/datapath-protocol.h"
  31 #include "packets.h"
  32 #include "unaligned.h"
  33 #include "vlog.h"
  34
  35 VLOG_DEFINE_THIS_MODULE(flow);
  36
  37 COVERAGE_DEFINE(flow_extract);
  38
  39 static struct arp_eth_header *
  40 pull_arp(struct ofpbuf *packet)
  41 {
  42     return ofpbuf_try_pull(packet, ARP_ETH_HEADER_LEN);
  43 }
  44
  45 static struct ip_header *
  46 pull_ip(struct ofpbuf *packet)
  47 {
  48     if (packet->size >= IP_HEADER_LEN) {
  49         struct ip_header *ip = packet->data;
  50         int ip_len = IP_IHL(ip->ip_ihl_ver) * 4;
  51         if (ip_len >= IP_HEADER_LEN && packet->size >= ip_len) {
  52             return ofpbuf_pull(packet, ip_len);
  53         }
  54     }
  55     return NULL;
  56 }
  57
  58 static struct tcp_header *
  59 pull_tcp(struct ofpbuf *packet)
  60 {
  61     if (packet->size >= TCP_HEADER_LEN) {
  62         struct tcp_header *tcp = packet->data;
  63         int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
  64         if (tcp_len >= TCP_HEADER_LEN && packet->size >= tcp_len) {
  65             return ofpbuf_pull(packet, tcp_len);
  66         }
  67     }
  68     return NULL;
  69 }
  70
  71 static struct udp_header *
  72 pull_udp(struct ofpbuf *packet)
  73 {
  74     return ofpbuf_try_pull(packet, UDP_HEADER_LEN);
  75 }
  76
  77 static struct icmp_header *
  78 pull_icmp(struct ofpbuf *packet)
  79 {
  80     return ofpbuf_try_pull(packet, ICMP_HEADER_LEN);
  81 }
  82
  83 static void
  84 parse_vlan(struct ofpbuf *b, struct flow *flow)
  85 {
  86     struct qtag_prefix {
  87         ovs_be16 eth_type;      /* ETH_TYPE_VLAN */
  88         ovs_be16 tci;
  89     };
  90
  91     if (b->size >= sizeof(struct qtag_prefix) + sizeof(ovs_be16)) {
  92         struct qtag_prefix *qp = ofpbuf_pull(b, sizeof *qp);
  93         flow->vlan_tci = qp->tci | htons(VLAN_CFI);
  94     }
  95 }
  96
  97 static ovs_be16
  98 parse_ethertype(struct ofpbuf *b)
  99 {
 100     struct llc_snap_header *llc;
 101     ovs_be16 proto;
 102
 103     proto = *(ovs_be16 *) ofpbuf_pull(b, sizeof proto);
 104     if (ntohs(proto) >= ETH_TYPE_MIN) {
 105         return proto;
 106     }
 107
 108     if (b->size < sizeof *llc) {
 109         return htons(FLOW_DL_TYPE_NONE);
 110     }
 111
 112     llc = b->data;
 113     if (llc->llc.llc_dsap != LLC_DSAP_SNAP
 114         || llc->llc.llc_ssap != LLC_SSAP_SNAP
 115         || llc->llc.llc_cntl != LLC_CNTL_SNAP
 116         || memcmp(llc->snap.snap_org, SNAP_ORG_ETHERNET,
 117                   sizeof llc->snap.snap_org)) {
 118         return htons(FLOW_DL_TYPE_NONE);
 119     }
 120
 121     ofpbuf_pull(b, sizeof *llc);
 122     return llc->snap.snap_type;
 123 }
 124
 125 /* Initializes 'flow' members from 'packet', 'tun_id', and 'in_port.
 126  * Initializes 'packet' header pointers as follows:
 127  *
 128  *    - packet->l2 to the start of the Ethernet header.
 129  *
 130  *    - packet->l3 to just past the Ethernet header, or just past the
 131  *      vlan_header if one is present, to the first byte of the payload of the
 132  *      Ethernet frame.
 133  *
 134  *    - packet->l4 to just past the IPv4 header, if one is present and has a
 135  *      correct length, and otherwise NULL.
 136  *
 137  *    - packet->l7 to just past the TCP or UDP or ICMP header, if one is
 138  *      present and has a correct length, and otherwise NULL.
 139  */
 140 int
 141 flow_extract(struct ofpbuf *packet, ovs_be64 tun_id, uint16_t in_port,
 142              struct flow *flow)
 143 {
 144     struct ofpbuf b = *packet;
 145     struct eth_header *eth;
 146     int retval = 0;
 147
 148     COVERAGE_INC(flow_extract);
 149
 150     memset(flow, 0, sizeof *flow);
 151     flow->tun_id = tun_id;
 152     flow->in_port = in_port;
 153
 154     packet->l2 = b.data;
 155     packet->l3 = NULL;
 156     packet->l4 = NULL;
 157     packet->l7 = NULL;
 158
 159     if (b.size < sizeof *eth) {
 160         return 0;
 161     }
 162
 163     /* Link layer. */
 164     eth = b.data;
 165     memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
 166     memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
 167
 168     /* dl_type, vlan_tci. */
 169     ofpbuf_pull(&b, ETH_ADDR_LEN * 2);
 170     if (eth->eth_type == htons(ETH_TYPE_VLAN)) {
 171         parse_vlan(&b, flow);
 172     }
 173     flow->dl_type = parse_ethertype(&b);
 174
 175     /* Network layer. */
 176     packet->l3 = b.data;
 177     if (flow->dl_type == htons(ETH_TYPE_IP)) {
 178         const struct ip_header *nh = pull_ip(&b);
 179         if (nh) {
 180             flow->nw_src = get_unaligned_be32(&nh->ip_src);
 181             flow->nw_dst = get_unaligned_be32(&nh->ip_dst);
 182             flow->nw_tos = nh->ip_tos & IP_DSCP_MASK;
 183             flow->nw_proto = nh->ip_proto;
 184             packet->l4 = b.data;
 185             if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
 186                 if (flow->nw_proto == IP_TYPE_TCP) {
 187                     const struct tcp_header *tcp = pull_tcp(&b);
 188                     if (tcp) {
 189                         flow->tp_src = tcp->tcp_src;
 190                         flow->tp_dst = tcp->tcp_dst;
 191                         packet->l7 = b.data;
 192                     }
 193                 } else if (flow->nw_proto == IP_TYPE_UDP) {
 194                     const struct udp_header *udp = pull_udp(&b);
 195                     if (udp) {
 196                         flow->tp_src = udp->udp_src;
 197                         flow->tp_dst = udp->udp_dst;
 198                         packet->l7 = b.data;
 199                     }
 200                 } else if (flow->nw_proto == IP_TYPE_ICMP) {
 201                     const struct icmp_header *icmp = pull_icmp(&b);
 202                     if (icmp) {
 203                         flow->icmp_type = htons(icmp->icmp_type);
 204                         flow->icmp_code = htons(icmp->icmp_code);
 205                         packet->l7 = b.data;
 206                     }
 207                 }
 208             } else {
 209                 retval = 1;
 210             }
 211         }
 212     } else if (flow->dl_type == htons(ETH_TYPE_ARP)) {
 213         const struct arp_eth_header *arp = pull_arp(&b);
 214         if (arp && arp->ar_hrd == htons(1)
 215             && arp->ar_pro == htons(ETH_TYPE_IP)
 216             && arp->ar_hln == ETH_ADDR_LEN
 217             && arp->ar_pln == 4) {
 218             /* We only match on the lower 8 bits of the opcode. */
 219             if (ntohs(arp->ar_op) <= 0xff) {
 220                 flow->nw_proto = ntohs(arp->ar_op);
 221             }
 222
 223             if ((flow->nw_proto == ARP_OP_REQUEST)
 224                 || (flow->nw_proto == ARP_OP_REPLY)) {
 225                 flow->nw_src = arp->ar_spa;
 226                 flow->nw_dst = arp->ar_tpa;
 227             }
 228         }
 229     }
 230     return retval;
 231 }
 232
 233 /* Extracts the flow stats for a packet.  The 'flow' and 'packet'
 234  * arguments must have been initialized through a call to flow_extract().
 235  */
 236 void
 237 flow_extract_stats(const struct flow *flow, struct ofpbuf *packet,
 238                    struct dpif_flow_stats *stats)
 239 {
 240     memset(stats, 0, sizeof(*stats));
 241
 242     if ((flow->dl_type == htons(ETH_TYPE_IP)) && packet->l4) {
 243         if ((flow->nw_proto == IP_TYPE_TCP) && packet->l7) {
 244             struct tcp_header *tcp = packet->l4;
 245             stats->tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
 246         }
 247     }
 248
 249     stats->n_bytes = packet->size;
 250     stats->n_packets = 1;
 251 }
 252
 253 char *
 254 flow_to_string(const struct flow *flow)
 255 {
 256     struct ds ds = DS_EMPTY_INITIALIZER;
 257     flow_format(&ds, flow);
 258     return ds_cstr(&ds);
 259 }
 260
 261 void
 262 flow_format(struct ds *ds, const struct flow *flow)
 263 {
 264     ds_put_format(ds, "tunnel%#"PRIx64":in_port%04"PRIx16":tci(",
 265                   flow->tun_id, flow->in_port);
 266     if (flow->vlan_tci) {
 267         ds_put_format(ds, "vlan%"PRIu16",pcp%d",
 268                       vlan_tci_to_vid(flow->vlan_tci),
 269                       vlan_tci_to_pcp(flow->vlan_tci));
 270     } else {
 271         ds_put_char(ds, '0');
 272     }
 273     ds_put_format(ds, ") mac"ETH_ADDR_FMT"->"ETH_ADDR_FMT
 274                       " type%04"PRIx16
 275                       " proto%"PRIu8
 276                       " tos%"PRIu8
 277                       " ip"IP_FMT"->"IP_FMT
 278                       " port%"PRIu16"->%"PRIu16,
 279                   ETH_ADDR_ARGS(flow->dl_src),
 280                   ETH_ADDR_ARGS(flow->dl_dst),
 281                   ntohs(flow->dl_type),
 282                   flow->nw_proto,
 283                   flow->nw_tos,
 284                   IP_ARGS(&flow->nw_src),
 285                   IP_ARGS(&flow->nw_dst),
 286                   ntohs(flow->tp_src),
 287                   ntohs(flow->tp_dst));
 288 }
 289
 290 void
 291 flow_print(FILE *stream, const struct flow *flow)
 292 {
 293     char *s = flow_to_string(flow);
 294     fputs(s, stream);
 295     free(s);
 296 }
 297 \f
 298 /* flow_wildcards functions. */
 299
 300 /* Initializes 'wc' as a set of wildcards that matches every packet. */
 301 void
 302 flow_wildcards_init_catchall(struct flow_wildcards *wc)
 303 {
 304     wc->wildcards = FWW_ALL;
 305     wc->tun_id_mask = htonll(0);
 306     wc->nw_src_mask = htonl(0);
 307     wc->nw_dst_mask = htonl(0);
 308     memset(wc->reg_masks, 0, sizeof wc->reg_masks);
 309     wc->vlan_tci_mask = htons(0);
 310     wc->zero = 0;
 311 }
 312
 313 /* Initializes 'wc' as an exact-match set of wildcards; that is, 'wc' does not
 314  * wildcard any bits or fields. */
 315 void
 316 flow_wildcards_init_exact(struct flow_wildcards *wc)
 317 {
 318     wc->wildcards = 0;
 319     wc->tun_id_mask = htonll(UINT64_MAX);
 320     wc->nw_src_mask = htonl(UINT32_MAX);
 321     wc->nw_dst_mask = htonl(UINT32_MAX);
 322     memset(wc->reg_masks, 0xff, sizeof wc->reg_masks);
 323     wc->vlan_tci_mask = htons(UINT16_MAX);
 324     wc->zero = 0;
 325 }
 326
 327 /* Returns true if 'wc' is exact-match, false if 'wc' wildcards any bits or
 328  * fields. */
 329 bool
 330 flow_wildcards_is_exact(const struct flow_wildcards *wc)
 331 {
 332     int i;
 333
 334     if (wc->wildcards
 335         || wc->tun_id_mask != htonll(UINT64_MAX)
 336         || wc->nw_src_mask != htonl(UINT32_MAX)
 337         || wc->nw_dst_mask != htonl(UINT32_MAX)
 338         || wc->vlan_tci_mask != htons(UINT16_MAX)) {
 339         return false;
 340     }
 341
 342     for (i = 0; i < FLOW_N_REGS; i++) {
 343         if (wc->reg_masks[i] != htonl(UINT32_MAX)) {
 344             return false;
 345         }
 346     }
 347
 348     return true;
 349 }
 350
 351 /* Initializes 'dst' as the combination of wildcards in 'src1' and 'src2'.
 352  * That is, a bit or a field is wildcarded in 'dst' if it is wildcarded in
 353  * 'src1' or 'src2' or both.  */
 354 void
 355 flow_wildcards_combine(struct flow_wildcards *dst,
 356                        const struct flow_wildcards *src1,
 357                        const struct flow_wildcards *src2)
 358 {
 359     int i;
 360
 361     dst->wildcards = src1->wildcards | src2->wildcards;
 362     dst->tun_id_mask = src1->tun_id_mask & src2->tun_id_mask;
 363     dst->nw_src_mask = src1->nw_src_mask & src2->nw_src_mask;
 364     dst->nw_dst_mask = src1->nw_dst_mask & src2->nw_dst_mask;
 365     for (i = 0; i < FLOW_N_REGS; i++) {
 366         dst->reg_masks[i] = src1->reg_masks[i] & src2->reg_masks[i];
 367     }
 368     dst->vlan_tci_mask = src1->vlan_tci_mask & src2->vlan_tci_mask;
 369 }
 370
 371 /* Returns a hash of the wildcards in 'wc'. */
 372 uint32_t
 373 flow_wildcards_hash(const struct flow_wildcards *wc)
 374 {
 375     /* If you change struct flow_wildcards and thereby trigger this
 376      * assertion, please check that the new struct flow_wildcards has no holes
 377      * in it before you update the assertion. */
 378     BUILD_ASSERT_DECL(sizeof *wc == 24 + FLOW_N_REGS * 4);
 379     return hash_bytes(wc, sizeof *wc, 0);
 380 }
 381
 382 /* Returns true if 'a' and 'b' represent the same wildcards, false if they are
 383  * different. */
 384 bool
 385 flow_wildcards_equal(const struct flow_wildcards *a,
 386                      const struct flow_wildcards *b)
 387 {
 388     int i;
 389
 390     if (a->wildcards != b->wildcards
 391         || a->tun_id_mask != b->tun_id_mask
 392         || a->nw_src_mask != b->nw_src_mask
 393         || a->nw_dst_mask != b->nw_dst_mask
 394         || a->vlan_tci_mask != b->vlan_tci_mask) {
 395         return false;
 396     }
 397
 398     for (i = 0; i < FLOW_N_REGS; i++) {
 399         if (a->reg_masks[i] != b->reg_masks[i]) {
 400             return false;
 401         }
 402     }
 403
 404     return true;
 405 }
 406
 407 /* Returns true if at least one bit or field is wildcarded in 'a' but not in
 408  * 'b', false otherwise. */
 409 bool
 410 flow_wildcards_has_extra(const struct flow_wildcards *a,
 411                          const struct flow_wildcards *b)
 412 {
 413     int i;
 414
 415     for (i = 0; i < FLOW_N_REGS; i++) {
 416         if ((a->reg_masks[i] & b->reg_masks[i]) != b->reg_masks[i]) {
 417             return true;
 418         }
 419     }
 420
 421     return (a->wildcards & ~b->wildcards
 422             || (a->tun_id_mask & b->tun_id_mask) != b->tun_id_mask
 423             || (a->nw_src_mask & b->nw_src_mask) != b->nw_src_mask
 424             || (a->nw_dst_mask & b->nw_dst_mask) != b->nw_dst_mask
 425             || (a->vlan_tci_mask & b->vlan_tci_mask) != b->vlan_tci_mask);
 426 }
 427
 428 static bool
 429 set_nw_mask(ovs_be32 *maskp, ovs_be32 mask)
 430 {
 431     if (ip_is_cidr(mask)) {
 432         *maskp = mask;
 433         return true;
 434     } else {
 435         return false;
 436     }
 437 }
 438
 439 /* Sets the IP (or ARP) source wildcard mask to CIDR 'mask' (consisting of N
 440  * high-order 1-bit and 32-N low-order 0-bits).  Returns true if successful,
 441  * false if 'mask' is not a CIDR mask.  */
 442 bool
 443 flow_wildcards_set_nw_src_mask(struct flow_wildcards *wc, ovs_be32 mask)
 444 {
 445     return set_nw_mask(&wc->nw_src_mask, mask);
 446 }
 447
 448 /* Sets the IP (or ARP) destination wildcard mask to CIDR 'mask' (consisting of
 449  * N high-order 1-bit and 32-N low-order 0-bits).  Returns true if successful,
 450  * false if 'mask' is not a CIDR mask.  */
 451 bool
 452 flow_wildcards_set_nw_dst_mask(struct flow_wildcards *wc, ovs_be32 mask)
 453 {
 454     return set_nw_mask(&wc->nw_dst_mask, mask);
 455 }
 456
 457 /* Sets the wildcard mask for register 'idx' in 'wc' to 'mask'.
 458  * (A 0-bit indicates a wildcard bit.) */
 459 void
 460 flow_wildcards_set_reg_mask(struct flow_wildcards *wc, int idx, uint32_t mask)
 461 {
 462     wc->reg_masks[idx] = mask;
 463 }