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 void
  81 parse_vlan(struct ofpbuf *b, flow_t *flow)
  82 {
  83     struct qtag_prefix {
  84         uint16_t eth_type;      /* ETH_TYPE_VLAN */
  85         uint16_t tci;
  86     };
  87
  88     if (b->size >= sizeof(struct qtag_prefix) + sizeof(uint16_t)) {
  89         struct qtag_prefix *qp = ofpbuf_pull(b, sizeof *qp);
  90         flow->dl_vlan = qp->tci & htons(VLAN_VID_MASK);
  91         flow->dl_vlan_pcp = (ntohs(qp->tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT;
  92     }
  93 }
  94
  95 static uint16_t
  96 parse_ethertype(struct ofpbuf *b)
  97 {
  98     struct llc_snap_header *llc;
  99     uint16_t proto;
 100
 101     proto = *(uint16_t *) ofpbuf_pull(b, sizeof proto);
 102     if (ntohs(proto) >= ODP_DL_TYPE_ETH2_CUTOFF) {
 103         return proto;
 104     }
 105
 106     if (b->size < sizeof *llc) {
 107         return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
 108     }
 109
 110     llc = b->data;
 111     if (llc->llc.llc_dsap != LLC_DSAP_SNAP
 112         || llc->llc.llc_ssap != LLC_SSAP_SNAP
 113         || llc->llc.llc_cntl != LLC_CNTL_SNAP
 114         || memcmp(llc->snap.snap_org, SNAP_ORG_ETHERNET,
 115                   sizeof llc->snap.snap_org)) {
 116         return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
 117     }
 118
 119     ofpbuf_pull(b, sizeof *llc);
 120     return llc->snap.snap_type;
 121 }
 122
 123 /* 'tun_id' is in network byte order, while 'in_port' is in host byte order.
 124  * These byte orders are the same as they are in struct odp_flow_key.
 125  *
 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, uint32_t tun_id, uint16_t in_port,
 142              flow_t *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     flow->dl_vlan = htons(OFP_VLAN_NONE);
 154
 155     packet->l2 = b.data;
 156     packet->l3 = NULL;
 157     packet->l4 = NULL;
 158     packet->l7 = NULL;
 159
 160     if (b.size < sizeof *eth) {
 161         return 0;
 162     }
 163
 164     /* Link layer. */
 165     eth = b.data;
 166     memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
 167     memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
 168
 169     /* dl_type, dl_vlan, dl_vlan_pcp. */
 170     ofpbuf_pull(&b, ETH_ADDR_LEN * 2);
 171     if (eth->eth_type == htons(ETH_TYPE_VLAN)) {
 172         parse_vlan(&b, flow);
 173     }
 174     flow->dl_type = parse_ethertype(&b);
 175
 176     /* Network layer. */
 177     packet->l3 = b.data;
 178     if (flow->dl_type == htons(ETH_TYPE_IP)) {
 179         const struct ip_header *nh = pull_ip(&b);
 180         if (nh) {
 181             flow->nw_src = get_unaligned_u32(&nh->ip_src);
 182             flow->nw_dst = get_unaligned_u32(&nh->ip_dst);
 183             flow->nw_tos = nh->ip_tos & IP_DSCP_MASK;
 184             flow->nw_proto = nh->ip_proto;
 185             packet->l4 = b.data;
 186             if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
 187                 if (flow->nw_proto == IP_TYPE_TCP) {
 188                     const struct tcp_header *tcp = pull_tcp(&b);
 189                     if (tcp) {
 190                         flow->tp_src = tcp->tcp_src;
 191                         flow->tp_dst = tcp->tcp_dst;
 192                         packet->l7 = b.data;
 193                     }
 194                 } else if (flow->nw_proto == IP_TYPE_UDP) {
 195                     const struct udp_header *udp = pull_udp(&b);
 196                     if (udp) {
 197                         flow->tp_src = udp->udp_src;
 198                         flow->tp_dst = udp->udp_dst;
 199                         packet->l7 = b.data;
 200                     }
 201                 } else if (flow->nw_proto == IP_TYPE_ICMP) {
 202                     const struct icmp_header *icmp = pull_icmp(&b);
 203                     if (icmp) {
 204                         flow->icmp_type = htons(icmp->icmp_type);
 205                         flow->icmp_code = htons(icmp->icmp_code);
 206                         packet->l7 = b.data;
 207                     }
 208                 }
 209             } else {
 210                 retval = 1;
 211             }
 212         }
 213     } else if (flow->dl_type == htons(ETH_TYPE_ARP)) {
 214         const struct arp_eth_header *arp = pull_arp(&b);
 215         if (arp && arp->ar_hrd == htons(1)
 216             && arp->ar_pro == htons(ETH_TYPE_IP)
 217             && arp->ar_hln == ETH_ADDR_LEN
 218             && arp->ar_pln == 4) {
 219             /* We only match on the lower 8 bits of the opcode. */
 220             if (ntohs(arp->ar_op) <= 0xff) {
 221                 flow->nw_proto = ntohs(arp->ar_op);
 222             }
 223
 224             if ((flow->nw_proto == ARP_OP_REQUEST)
 225                 || (flow->nw_proto == ARP_OP_REPLY)) {
 226                 flow->nw_src = arp->ar_spa;
 227                 flow->nw_dst = arp->ar_tpa;
 228             }
 229         }
 230     }
 231     return retval;
 232 }
 233
 234 /* Extracts the flow stats for a packet.  The 'flow' and 'packet'
 235  * arguments must have been initialized through a call to flow_extract().
 236  */
 237 void
 238 flow_extract_stats(const flow_t *flow, struct ofpbuf *packet,
 239         struct odp_flow_stats *stats)
 240 {
 241     memset(stats, '\0', sizeof(*stats));
 242
 243     if ((flow->dl_type == htons(ETH_TYPE_IP)) && packet->l4) {
 244         if ((flow->nw_proto == IP_TYPE_TCP) && packet->l7) {
 245             struct tcp_header *tcp = packet->l4;
 246             stats->tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
 247         }
 248     }
 249
 250     stats->n_bytes = packet->size;
 251     stats->n_packets = 1;
 252 }
 253
 254 /* Extract 'flow' with 'wildcards' into the OpenFlow match structure
 255  * 'match'. */
 256 void
 257 flow_to_match(const flow_t *flow, uint32_t wildcards, bool tun_id_from_cookie,
 258               struct ofp_match *match)
 259 {
 260     if (!tun_id_from_cookie) {
 261         wildcards &= OFPFW_ALL;
 262     }
 263     match->wildcards = htonl(wildcards);
 264
 265     match->in_port = htons(flow->in_port == ODPP_LOCAL ? OFPP_LOCAL
 266                            : flow->in_port);
 267     match->dl_vlan = flow->dl_vlan;
 268     match->dl_vlan_pcp = flow->dl_vlan_pcp;
 269     memcpy(match->dl_src, flow->dl_src, ETH_ADDR_LEN);
 270     memcpy(match->dl_dst, flow->dl_dst, ETH_ADDR_LEN);
 271     match->dl_type = flow->dl_type;
 272     match->nw_src = flow->nw_src;
 273     match->nw_dst = flow->nw_dst;
 274     match->nw_tos = flow->nw_tos;
 275     match->nw_proto = flow->nw_proto;
 276     match->tp_src = flow->tp_src;
 277     match->tp_dst = flow->tp_dst;
 278     memset(match->pad1, '\0', sizeof match->pad1);
 279     memset(match->pad2, '\0', sizeof match->pad2);
 280 }
 281
 282 void
 283 flow_from_match(const struct ofp_match *match, bool tun_id_from_cookie,
 284                 uint64_t cookie, flow_t *flow, uint32_t *flow_wildcards)
 285 {
 286         uint32_t wildcards = ntohl(match->wildcards);
 287
 288     flow->nw_src = match->nw_src;
 289     flow->nw_dst = match->nw_dst;
 290     if (tun_id_from_cookie && !(wildcards & NXFW_TUN_ID)) {
 291         flow->tun_id = htonl(ntohll(cookie) >> 32);
 292     } else {
 293         wildcards |= NXFW_TUN_ID;
 294         flow->tun_id = 0;
 295     }
 296     flow->in_port = (match->in_port == htons(OFPP_LOCAL) ? ODPP_LOCAL
 297                      : ntohs(match->in_port));
 298     flow->dl_vlan = match->dl_vlan;
 299     flow->dl_vlan_pcp = match->dl_vlan_pcp;
 300     flow->dl_type = match->dl_type;
 301     flow->tp_src = match->tp_src;
 302     flow->tp_dst = match->tp_dst;
 303     memcpy(flow->dl_src, match->dl_src, ETH_ADDR_LEN);
 304     memcpy(flow->dl_dst, match->dl_dst, ETH_ADDR_LEN);
 305     flow->nw_tos = match->nw_tos;
 306     flow->nw_proto = match->nw_proto;
 307     memset(flow->reserved, 0, sizeof flow->reserved);
 308
 309     if (flow_wildcards) {
 310         *flow_wildcards = wildcards;
 311     }
 312 }
 313
 314 char *
 315 flow_to_string(const flow_t *flow)
 316 {
 317     struct ds ds = DS_EMPTY_INITIALIZER;
 318     flow_format(&ds, flow);
 319     return ds_cstr(&ds);
 320 }
 321
 322 void
 323 flow_format(struct ds *ds, const flow_t *flow)
 324 {
 325     ds_put_format(ds, "tunnel%08"PRIx32":in_port%04"PRIx16
 326                       ":vlan%"PRIu16":pcp%"PRIu8
 327                       " mac"ETH_ADDR_FMT"->"ETH_ADDR_FMT
 328                       " type%04"PRIx16
 329                       " proto%"PRIu8
 330                       " tos%"PRIu8
 331                       " ip"IP_FMT"->"IP_FMT
 332                       " port%"PRIu16"->%"PRIu16,
 333                   ntohl(flow->tun_id),
 334                   flow->in_port,
 335                   ntohs(flow->dl_vlan),
 336                   flow->dl_vlan_pcp,
 337                   ETH_ADDR_ARGS(flow->dl_src),
 338                   ETH_ADDR_ARGS(flow->dl_dst),
 339                   ntohs(flow->dl_type),
 340                   flow->nw_proto,
 341                   flow->nw_tos,
 342                   IP_ARGS(&flow->nw_src),
 343                   IP_ARGS(&flow->nw_dst),
 344                   ntohs(flow->tp_src),
 345                   ntohs(flow->tp_dst));
 346 }
 347
 348 void
 349 flow_print(FILE *stream, const flow_t *flow)
 350 {
 351     char *s = flow_to_string(flow);
 352     fputs(s, stream);
 353     free(s);
 354 }