lib/flow.c

   1 /*
   2  * Copyright (c) 2008, 2009 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
  31 #include "vlog.h"
  32 #define THIS_MODULE VLM_flow
  33
  34 static struct ip_header *
  35 pull_ip(struct ofpbuf *packet)
  36 {
  37     if (packet->size >= IP_HEADER_LEN) {
  38         struct ip_header *ip = packet->data;
  39         int ip_len = IP_IHL(ip->ip_ihl_ver) * 4;
  40         if (ip_len >= IP_HEADER_LEN && packet->size >= ip_len) {
  41             return ofpbuf_pull(packet, ip_len);
  42         }
  43     }
  44     return NULL;
  45 }
  46
  47 static struct tcp_header *
  48 pull_tcp(struct ofpbuf *packet)
  49 {
  50     if (packet->size >= TCP_HEADER_LEN) {
  51         struct tcp_header *tcp = packet->data;
  52         int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
  53         if (tcp_len >= TCP_HEADER_LEN && packet->size >= tcp_len) {
  54             return ofpbuf_pull(packet, tcp_len);
  55         }
  56     }
  57     return NULL;
  58 }
  59
  60 static struct udp_header *
  61 pull_udp(struct ofpbuf *packet)
  62 {
  63     return ofpbuf_try_pull(packet, UDP_HEADER_LEN);
  64 }
  65
  66 static struct icmp_header *
  67 pull_icmp(struct ofpbuf *packet)
  68 {
  69     return ofpbuf_try_pull(packet, ICMP_HEADER_LEN);
  70 }
  71
  72 static struct eth_header *
  73 pull_eth(struct ofpbuf *packet)
  74 {
  75     return ofpbuf_try_pull(packet, ETH_HEADER_LEN);
  76 }
  77
  78 static struct vlan_header *
  79 pull_vlan(struct ofpbuf *packet)
  80 {
  81     return ofpbuf_try_pull(packet, VLAN_HEADER_LEN);
  82 }
  83
  84 /* Returns 1 if 'packet' is an IP fragment, 0 otherwise. */
  85 int
  86 flow_extract(struct ofpbuf *packet, uint16_t in_port, flow_t *flow)
  87 {
  88     struct ofpbuf b = *packet;
  89     struct eth_header *eth;
  90     int retval = 0;
  91
  92     COVERAGE_INC(flow_extract);
  93
  94     memset(flow, 0, sizeof *flow);
  95     flow->dl_vlan = htons(OFP_VLAN_NONE);
  96     flow->in_port = in_port;
  97
  98     packet->l2 = b.data;
  99     packet->l3 = NULL;
 100     packet->l4 = NULL;
 101     packet->l7 = NULL;
 102
 103     eth = pull_eth(&b);
 104     if (eth) {
 105         if (ntohs(eth->eth_type) >= OFP_DL_TYPE_ETH2_CUTOFF) {
 106             /* This is an Ethernet II frame */
 107             flow->dl_type = eth->eth_type;
 108         } else {
 109             /* This is an 802.2 frame */
 110             struct llc_header *llc = ofpbuf_at(&b, 0, sizeof *llc);
 111             struct snap_header *snap = ofpbuf_at(&b, sizeof *llc,
 112                                                  sizeof *snap);
 113             if (llc == NULL) {
 114                 return 0;
 115             }
 116             if (snap
 117                 && llc->llc_dsap == LLC_DSAP_SNAP
 118                 && llc->llc_ssap == LLC_SSAP_SNAP
 119                 && llc->llc_cntl == LLC_CNTL_SNAP
 120                 && !memcmp(snap->snap_org, SNAP_ORG_ETHERNET,
 121                            sizeof snap->snap_org)) {
 122                 flow->dl_type = snap->snap_type;
 123                 ofpbuf_pull(&b, LLC_SNAP_HEADER_LEN);
 124             } else {
 125                 flow->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
 126                 ofpbuf_pull(&b, sizeof(struct llc_header));
 127             }
 128         }
 129
 130         /* Check for a VLAN tag */
 131         if (flow->dl_type == htons(ETH_TYPE_VLAN)) {
 132             struct vlan_header *vh = pull_vlan(&b);
 133             if (vh) {
 134                 flow->dl_type = vh->vlan_next_type;
 135                 flow->dl_vlan = vh->vlan_tci & htons(VLAN_VID_MASK);
 136             }
 137         }
 138         memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
 139         memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
 140
 141         packet->l3 = b.data;
 142         if (flow->dl_type == htons(ETH_TYPE_IP)) {
 143             const struct ip_header *nh = pull_ip(&b);
 144             if (nh) {
 145                 flow->nw_src = nh->ip_src;
 146                 flow->nw_dst = nh->ip_dst;
 147                 flow->nw_proto = nh->ip_proto;
 148                 packet->l4 = b.data;
 149                 if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
 150                     if (flow->nw_proto == IP_TYPE_TCP) {
 151                         const struct tcp_header *tcp = pull_tcp(&b);
 152                         if (tcp) {
 153                             flow->tp_src = tcp->tcp_src;
 154                             flow->tp_dst = tcp->tcp_dst;
 155                             packet->l7 = b.data;
 156                         } else {
 157                             /* Avoid tricking other code into thinking that
 158                              * this packet has an L4 header. */
 159                             flow->nw_proto = 0;
 160                         }
 161                     } else if (flow->nw_proto == IP_TYPE_UDP) {
 162                         const struct udp_header *udp = pull_udp(&b);
 163                         if (udp) {
 164                             flow->tp_src = udp->udp_src;
 165                             flow->tp_dst = udp->udp_dst;
 166                             packet->l7 = b.data;
 167                         } else {
 168                             /* Avoid tricking other code into thinking that
 169                              * this packet has an L4 header. */
 170                             flow->nw_proto = 0;
 171                         }
 172                     } else if (flow->nw_proto == IP_TYPE_ICMP) {
 173                         const struct icmp_header *icmp = pull_icmp(&b);
 174                         if (icmp) {
 175                             flow->icmp_type = htons(icmp->icmp_type);
 176                             flow->icmp_code = htons(icmp->icmp_code);
 177                             packet->l7 = b.data;
 178                         } else {
 179                             /* Avoid tricking other code into thinking that
 180                              * this packet has an L4 header. */
 181                             flow->nw_proto = 0;
 182                         }
 183                     }
 184                 } else {
 185                     retval = 1;
 186                 }
 187             }
 188         }
 189     }
 190     return retval;
 191 }
 192
 193 /* Extracts the flow stats for a packet.  The 'flow' and 'packet'
 194  * arguments must have been initialized through a call to flow_extract().
 195  */
 196 void
 197 flow_extract_stats(const flow_t *flow, struct ofpbuf *packet,
 198         struct odp_flow_stats *stats)
 199 {
 200     memset(stats, '\0', sizeof(*stats));
 201
 202     if ((flow->dl_type == htons(ETH_TYPE_IP)) && packet->l4) {
 203         struct ip_header *ip = packet->l3;
 204         stats->ip_tos = ip->ip_tos;
 205         if ((flow->nw_proto == IP_TYPE_TCP) && packet->l7) {
 206             struct tcp_header *tcp = packet->l4;
 207             stats->tcp_flags = TCP_FLAGS(tcp->tcp_ctl);
 208         }
 209     }
 210
 211     stats->n_bytes = packet->size;
 212     stats->n_packets = 1;
 213 }
 214
 215 void
 216 flow_to_match(const flow_t *flow, uint32_t wildcards, struct ofp_match *match)
 217 {
 218     match->wildcards = htonl(wildcards);
 219     match->in_port = htons(flow->in_port == ODPP_LOCAL ? OFPP_LOCAL
 220                            : flow->in_port);
 221     match->dl_vlan = flow->dl_vlan;
 222     memcpy(match->dl_src, flow->dl_src, ETH_ADDR_LEN);
 223     memcpy(match->dl_dst, flow->dl_dst, ETH_ADDR_LEN);
 224     match->dl_type = flow->dl_type;
 225     match->nw_src = flow->nw_src;
 226     match->nw_dst = flow->nw_dst;
 227     match->nw_proto = flow->nw_proto;
 228     match->tp_src = flow->tp_src;
 229     match->tp_dst = flow->tp_dst;
 230     match->pad = 0;
 231 }
 232
 233 void
 234 flow_from_match(flow_t *flow, uint32_t *wildcards,
 235                 const struct ofp_match *match)
 236 {
 237     if (wildcards) {
 238         *wildcards = ntohl(match->wildcards);
 239     }
 240     flow->nw_src = match->nw_src;
 241     flow->nw_dst = match->nw_dst;
 242     flow->in_port = (match->in_port == htons(OFPP_LOCAL) ? ODPP_LOCAL
 243                      : ntohs(match->in_port));
 244     flow->dl_vlan = match->dl_vlan;
 245     flow->dl_type = match->dl_type;
 246     flow->tp_src = match->tp_src;
 247     flow->tp_dst = match->tp_dst;
 248     memcpy(flow->dl_src, match->dl_src, ETH_ADDR_LEN);
 249     memcpy(flow->dl_dst, match->dl_dst, ETH_ADDR_LEN);
 250     flow->nw_proto = match->nw_proto;
 251     flow->reserved = 0;
 252 }
 253
 254 char *
 255 flow_to_string(const flow_t *flow)
 256 {
 257     struct ds ds = DS_EMPTY_INITIALIZER;
 258     flow_format(&ds, flow);
 259     return ds_cstr(&ds);
 260 }
 261
 262 void
 263 flow_format(struct ds *ds, const flow_t *flow)
 264 {
 265     ds_put_format(ds, "port%04x:vlan%d mac"ETH_ADDR_FMT"->"ETH_ADDR_FMT" "
 266                   "type%04x proto%"PRId8" ip"IP_FMT"->"IP_FMT" port%d->%d",
 267                   flow->in_port, ntohs(flow->dl_vlan),
 268                   ETH_ADDR_ARGS(flow->dl_src), ETH_ADDR_ARGS(flow->dl_dst),
 269                   ntohs(flow->dl_type), flow->nw_proto,
 270                   IP_ARGS(&flow->nw_src), IP_ARGS(&flow->nw_dst),
 271                   ntohs(flow->tp_src), ntohs(flow->tp_dst));
 272 }
 273
 274 void
 275 flow_print(FILE *stream, const flow_t *flow)
 276 {
 277     char *s = flow_to_string(flow);
 278     fputs(s, stream);
 279     free(s);
 280 }