lib/flow.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 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 "coverage.h"
  24 #include "dynamic-string.h"
  25 #include "hash.h"
  26 #include "ofpbuf.h"
  27 #include "openflow/openflow.h"
  28 #include "openvswitch/datapath-protocol.h"
  29 #include "packets.h"
  30 #include "unaligned.h"
  31 #include "vlog.h"
  32 #include "xtoxll.h"
  33
  34 VLOG_DEFINE_THIS_MODULE(flow)
  35
  36 static struct arp_eth_header *
  37 pull_arp(struct ofpbuf *packet)
  38 {
  39     return ofpbuf_try_pull(packet, ARP_ETH_HEADER_LEN);
  40 }
  41
  42 static struct ip_header *
  43 pull_ip(struct ofpbuf *packet)
  44 {
  45     if (packet->size >= IP_HEADER_LEN) {
  46         struct ip_header *ip = packet->data;
  47         int ip_len = IP_IHL(ip->ip_ihl_ver) * 4;
  48         if (ip_len >= IP_HEADER_LEN && packet->size >= ip_len) {
  49             return ofpbuf_pull(packet, ip_len);
  50         }
  51     }
  52     return NULL;
  53 }
  54
  55 static struct tcp_header *
  56 pull_tcp(struct ofpbuf *packet)
  57 {
  58     if (packet->size >= TCP_HEADER_LEN) {
  59         struct tcp_header *tcp = packet->data;
  60         int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
  61         if (tcp_len >= TCP_HEADER_LEN && packet->size >= tcp_len) {
  62             return ofpbuf_pull(packet, tcp_len);
  63         }
  64     }
  65     return NULL;
  66 }
  67
  68 static struct udp_header *
  69 pull_udp(struct ofpbuf *packet)
  70 {
  71     return ofpbuf_try_pull(packet, UDP_HEADER_LEN);
  72 }
  73
  74 static struct icmp_header *
  75 pull_icmp(struct ofpbuf *packet)
  76 {
  77     return ofpbuf_try_pull(packet, ICMP_HEADER_LEN);
  78 }
  79
  80 static struct eth_header *
  81 pull_eth(struct ofpbuf *packet)
  82 {
  83     return ofpbuf_try_pull(packet, ETH_HEADER_LEN);
  84 }
  85
  86 static struct vlan_header *
  87 pull_vlan(struct ofpbuf *packet)
  88 {
  89     return ofpbuf_try_pull(packet, VLAN_HEADER_LEN);
  90 }
  91
  92 /* Returns 1 if 'packet' is an IP fragment, 0 otherwise.
  93  * 'tun_id' is in network byte order, while 'in_port' is in host byte order.
  94  * These byte orders are the same as they are in struct odp_flow_key. */
  95 int
  96 flow_extract(struct ofpbuf *packet, uint32_t tun_id, uint16_t in_port,
  97              flow_t *flow)
  98 {
  99     struct ofpbuf b = *packet;
 100     struct eth_header *eth;
 101     int retval = 0;
 102
 103     COVERAGE_INC(flow_extract);
 104
 105     memset(flow, 0, sizeof *flow);
 106     flow->tun_id = tun_id;
 107     flow->in_port = in_port;
 108     flow->dl_vlan = htons(OFP_VLAN_NONE);
 109
 110     packet->l2 = b.data;
 111     packet->l3 = NULL;
 112     packet->l4 = NULL;
 113     packet->l7 = NULL;
 114
 115     eth = pull_eth(&b);
 116     if (eth) {
 117         if (ntohs(eth->eth_type) >= OFP_DL_TYPE_ETH2_CUTOFF) {
 118             /* This is an Ethernet II frame */
 119             flow->dl_type = eth->eth_type;
 120         } else {
 121             /* This is an 802.2 frame */
 122             struct llc_header *llc = ofpbuf_at(&b, 0, sizeof *llc);
 123             struct snap_header *snap = ofpbuf_at(&b, sizeof *llc,
 124                                                  sizeof *snap);
 125             if (llc == NULL) {
 126                 return 0;
 127             }
 128             if (snap
 129                 && llc->llc_dsap == LLC_DSAP_SNAP
 130                 && llc->llc_ssap == LLC_SSAP_SNAP
 131                 && llc->llc_cntl == LLC_CNTL_SNAP
 132                 && !memcmp(snap->snap_org, SNAP_ORG_ETHERNET,
 133                            sizeof snap->snap_org)) {
 134                 flow->dl_type = snap->snap_type;
 135                 ofpbuf_pull(&b, LLC_SNAP_HEADER_LEN);
 136             } else {
 137                 flow->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
 138                 ofpbuf_pull(&b, sizeof(struct llc_header));
 139             }
 140         }
 141
 142         /* Check for a VLAN tag */
 143         if (flow->dl_type == htons(ETH_TYPE_VLAN)) {
 144             struct vlan_header *vh = pull_vlan(&b);
 145             if (vh) {
 146                 flow->dl_type = vh->vlan_next_type;
 147                 flow->dl_vlan = vh->vlan_tci & htons(VLAN_VID_MASK);
 148                 flow->dl_vlan_pcp = (ntohs(vh->vlan_tci) & 0xe000) >> 13;
 149             }
 150         }
 151         memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
 152         memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
 153
 154         packet->l3 = b.data;
 155         if (flow->dl_type == htons(ETH_TYPE_IP)) {
 156             const struct ip_header *nh = pull_ip(&b);
 157             if (nh) {
 158                 flow->nw_src = get_unaligned_u32(&nh->ip_src);
 159                 flow->nw_dst = get_unaligned_u32(&nh->ip_dst);
 160                 flow->nw_tos = nh->ip_tos & IP_DSCP_MASK;
 161                 flow->nw_proto = nh->ip_proto;
 162                 packet->l4 = b.data;
 163                 if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
 164                     if (flow->nw_proto == IP_TYPE_TCP) {
 165                         const struct tcp_header *tcp = pull_tcp(&b);
 166                         if (tcp) {
 167                             flow->tp_src = tcp->tcp_src;
 168                             flow->tp_dst = tcp->tcp_dst;
 169                             packet->l7 = b.data;
 170                         } else {
 171                             /* Avoid tricking other code into thinking that
 172                              * this packet has an L4 header. */
 173                             flow->nw_proto = 0;
 174                         }
 175                     } else if (flow->nw_proto == IP_TYPE_UDP) {
 176                         const struct udp_header *udp = pull_udp(&b);
 177                         if (udp) {
 178                             flow->tp_src = udp->udp_src;
 179                             flow->tp_dst = udp->udp_dst;
 180                             packet->l7 = b.data;
 181                         } else {
 182                             /* Avoid tricking other code into thinking that
 183                              * this packet has an L4 header. */
 184                             flow->nw_proto = 0;
 185                         }
 186                     } else if (flow->nw_proto == IP_TYPE_ICMP) {
 187                         const struct icmp_header *icmp = pull_icmp(&b);
 188                         if (icmp) {
 189                             flow->icmp_type = htons(icmp->icmp_type);
 190                             flow->icmp_code = htons(icmp->icmp_code);
 191                             packet->l7 = b.data;
 192                         } else {
 193                             /* Avoid tricking other code into thinking that
 194                              * this packet has an L4 header. */
 195                             flow->nw_proto = 0;
 196                         }
 197                     }
 198                 } else {
 199                     retval = 1;
 200                 }
 201             }
 202         } else if (flow->dl_type == htons(ETH_TYPE_ARP)) {
 203             const struct arp_eth_header *arp = pull_arp(&b);
 204             if (arp && arp->ar_hrd == htons(1)
 205                     && arp->ar_pro == htons(ETH_TYPE_IP)
 206                     && arp->ar_hln == ETH_ADDR_LEN
 207                     && arp->ar_pln == 4) {
 208                 /* We only match on the lower 8 bits of the opcode. */
 209                 if (ntohs(arp->ar_op) <= 0xff) {
 210                     flow->nw_proto = ntohs(arp->ar_op);
 211                 }
 212
 213                 if ((flow->nw_proto == ARP_OP_REQUEST)
 214                         || (flow->nw_proto == ARP_OP_REPLY)) {
 215                     flow->nw_src = arp->ar_spa;
 216                     flow->nw_dst = arp->ar_tpa;
 217                 }
 218             }
 219         }
 220     }
 221     return retval;
 222 }
 223
 224 /* Extracts the flow stats for a packet.  The 'flow' and 'packet'
 225  * arguments must have been initialized through a call to flow_extract().
 226  */
 227 void
 228 flow_extract_stats(const flow_t *flow, struct ofpbuf *packet,
 229         struct odp_flow_stats *stats)
 230 {
 231     memset(stats, '\0', sizeof(*stats));
 232
 233     if ((flow->dl_type == htons(ETH_TYPE_IP)) && packet->l4) {
 234         struct ip_header *ip = packet->l3;
 235         stats->ip_tos = ip->ip_tos;
 236         if ((flow->nw_proto == IP_TYPE_TCP) && packet->l7) {
 237             struct tcp_header *tcp = packet->l4;
 238             stats->tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
 239         }
 240     }
 241
 242     stats->n_bytes = packet->size;
 243     stats->n_packets = 1;
 244 }
 245
 246 /* Extract 'flow' with 'wildcards' into the OpenFlow match structure
 247  * 'match'. */
 248 void
 249 flow_to_match(const flow_t *flow, uint32_t wildcards, bool tun_id_from_cookie,
 250               struct ofp_match *match)
 251 {
 252     if (!tun_id_from_cookie) {
 253         wildcards &= OFPFW_ALL;
 254     }
 255     match->wildcards = htonl(wildcards);
 256
 257     match->in_port = htons(flow->in_port == ODPP_LOCAL ? OFPP_LOCAL
 258                            : flow->in_port);
 259     match->dl_vlan = flow->dl_vlan;
 260     match->dl_vlan_pcp = flow->dl_vlan_pcp;
 261     memcpy(match->dl_src, flow->dl_src, ETH_ADDR_LEN);
 262     memcpy(match->dl_dst, flow->dl_dst, ETH_ADDR_LEN);
 263     match->dl_type = flow->dl_type;
 264     match->nw_src = flow->nw_src;
 265     match->nw_dst = flow->nw_dst;
 266     match->nw_tos = flow->nw_tos;
 267     match->nw_proto = flow->nw_proto;
 268     match->tp_src = flow->tp_src;
 269     match->tp_dst = flow->tp_dst;
 270     memset(match->pad1, '\0', sizeof match->pad1);
 271     memset(match->pad2, '\0', sizeof match->pad2);
 272 }
 273
 274 void
 275 flow_from_match(const struct ofp_match *match, bool tun_id_from_cookie,
 276                 uint64_t cookie, flow_t *flow, uint32_t *flow_wildcards)
 277 {
 278         uint32_t wildcards = ntohl(match->wildcards);
 279
 280     flow->nw_src = match->nw_src;
 281     flow->nw_dst = match->nw_dst;
 282     if (tun_id_from_cookie && !(wildcards & NXFW_TUN_ID)) {
 283         flow->tun_id = htonl(ntohll(cookie) >> 32);
 284     } else {
 285         wildcards |= NXFW_TUN_ID;
 286         flow->tun_id = 0;
 287     }
 288     flow->in_port = (match->in_port == htons(OFPP_LOCAL) ? ODPP_LOCAL
 289                      : ntohs(match->in_port));
 290     flow->dl_vlan = match->dl_vlan;
 291     flow->dl_vlan_pcp = match->dl_vlan_pcp;
 292     flow->dl_type = match->dl_type;
 293     flow->tp_src = match->tp_src;
 294     flow->tp_dst = match->tp_dst;
 295     memcpy(flow->dl_src, match->dl_src, ETH_ADDR_LEN);
 296     memcpy(flow->dl_dst, match->dl_dst, ETH_ADDR_LEN);
 297     flow->nw_tos = match->nw_tos;
 298     flow->nw_proto = match->nw_proto;
 299     memset(flow->reserved, 0, sizeof flow->reserved);
 300
 301     if (flow_wildcards) {
 302         *flow_wildcards = wildcards;
 303     }
 304 }
 305
 306 char *
 307 flow_to_string(const flow_t *flow)
 308 {
 309     struct ds ds = DS_EMPTY_INITIALIZER;
 310     flow_format(&ds, flow);
 311     return ds_cstr(&ds);
 312 }
 313
 314 void
 315 flow_format(struct ds *ds, const flow_t *flow)
 316 {
 317     ds_put_format(ds, "tunnel%08"PRIx32":in_port%04"PRIx16
 318                       ":vlan%"PRIu16":pcp%"PRIu8
 319                       " mac"ETH_ADDR_FMT"->"ETH_ADDR_FMT
 320                       " type%04"PRIx16
 321                       " proto%"PRIu8
 322                       " tos%"PRIu8
 323                       " ip"IP_FMT"->"IP_FMT
 324                       " port%"PRIu16"->%"PRIu16,
 325                   ntohl(flow->tun_id),
 326                   flow->in_port,
 327                   ntohs(flow->dl_vlan),
 328                   flow->dl_vlan_pcp,
 329                   ETH_ADDR_ARGS(flow->dl_src),
 330                   ETH_ADDR_ARGS(flow->dl_dst),
 331                   ntohs(flow->dl_type),
 332                   flow->nw_proto,
 333                   flow->nw_tos,
 334                   IP_ARGS(&flow->nw_src),
 335                   IP_ARGS(&flow->nw_dst),
 336                   ntohs(flow->tp_src),
 337                   ntohs(flow->tp_dst));
 338 }
 339
 340 void
 341 flow_print(FILE *stream, const flow_t *flow)
 342 {
 343     char *s = flow_to_string(flow);
 344     fputs(s, stream);
 345     free(s);
 346 }