text: /*
   * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  #include "in-band.h"
  #include <arpa/inet.h>
  #include <errno.h>
  #include <inttypes.h>
  #include <sys/socket.h>
  #include <net/if.h>
  #include <string.h>
  #include <stdlib.h>
  #include "classifier.h"
  #include "dhcp.h"
  #include "flow.h"
  #include "netdev.h"
  #include "netlink.h"
  #include "odp-util.h"
  #include "ofproto.h"
  #include "ofpbuf.h"
  #include "ofproto-provider.h"
  #include "openflow/openflow.h"
  #include "packets.h"
  #include "poll-loop.h"
  #include "timeval.h"
  #include "vlog.h"
  
  VLOG_DEFINE_THIS_MODULE(in_band);
  
  /* Priorities used in classifier for in-band rules.  These values are higher
   * than any that may be set with OpenFlow, and "18" kind of looks like "IB".
   * The ordering of priorities is not important because all of the rules set up
   * by in-band control have the same action.  The only reason to use more than
   * one priority is to make the kind of flow easier to see during debugging. */
  enum {
      /* One set per bridge. */
      IBR_FROM_LOCAL_DHCP = 180000, /* (a) From local port, DHCP. */
      IBR_TO_LOCAL_ARP,             /* (b) To local port, ARP. */
      IBR_FROM_LOCAL_ARP,           /* (c) From local port, ARP. */
  
      /* One set per unique next-hop MAC. */
      IBR_TO_NEXT_HOP_ARP,          /* (d) To remote MAC, ARP. */
      IBR_FROM_NEXT_HOP_ARP,        /* (e) From remote MAC, ARP. */
  
      /* One set per unique remote IP address. */
      IBR_TO_REMOTE_ARP,            /* (f) To remote IP, ARP. */
      IBR_FROM_REMOTE_ARP,          /* (g) From remote IP, ARP. */
  
      /* One set per unique remote (IP,port) pair. */
      IBR_TO_REMOTE_TCP,            /* (h) To remote IP, TCP port. */
      IBR_FROM_REMOTE_TCP           /* (i) From remote IP, TCP port. */
  };
  
  /* Track one remote IP and next hop information. */
  struct in_band_remote {
      struct sockaddr_in remote_addr; /* IP address, in network byte order. */
      uint8_t remote_mac[ETH_ADDR_LEN]; /* Next-hop MAC, all-zeros if unknown. */
      uint8_t last_remote_mac[ETH_ADDR_LEN]; /* Previous nonzero next-hop MAC. */
      struct netdev *remote_netdev; /* Device to send to next-hop MAC. */
  };
  
  /* What to do to an in_band_rule. */
  enum in_band_op {
      ADD,                       /* Add the rule to ofproto's flow table. */
      DELETE                     /* Delete the rule from ofproto's flow table. */
  };
  
  /* A rule to add to or delete from ofproto's flow table.  */
  struct in_band_rule {
      struct cls_rule cls_rule;
      enum in_band_op op;
  };
  
  struct in_band {
      struct ofproto *ofproto;
      int queue_id;
  
      /* Remote information. */
      time_t next_remote_refresh; /* Refresh timer. */
      struct in_band_remote *remotes;
      size_t n_remotes;
  
      /* Local information. */
      time_t next_local_refresh;       /* Refresh timer. */
      uint8_t local_mac[ETH_ADDR_LEN]; /* Current MAC. */
      struct netdev *local_netdev;     /* Local port's network device. */
  
      /* Flow tracking. */
      struct hmap rules;          /* Contains "struct in_band_rule"s. */
  };
  
  static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 60);
  
  static int
  refresh_remote(struct in_band *ib, struct in_band_remote *r)
  {
      struct in_addr next_hop_inaddr;
      char *next_hop_dev;
      int retval;
  
      /* Find the next-hop IP address. */
      memset(r->remote_mac, 0, sizeof r->remote_mac);
      retval = netdev_get_next_hop(ib->local_netdev, &r->remote_addr.sin_addr,
                                   &next_hop_inaddr, &next_hop_dev);
      if (retval) {
          VLOG_WARN("cannot find route for controller ("IP_FMT"): %s",
                    IP_ARGS(&r->remote_addr.sin_addr), strerror(retval));
          return 1;
      }
      if (!next_hop_inaddr.s_addr) {
          next_hop_inaddr = r->remote_addr.sin_addr;
      }
  
      /* Open the next-hop network device. */
      if (!r->remote_netdev
          || strcmp(netdev_get_name(r->remote_netdev), next_hop_dev))
      {
          netdev_close(r->remote_netdev);
  
          retval = netdev_open(next_hop_dev, "system", &r->remote_netdev);
          if (retval) {
              VLOG_WARN_RL(&rl, "cannot open netdev %s (next hop "
                           "to controller "IP_FMT"): %s",
                           next_hop_dev, IP_ARGS(&r->remote_addr.sin_addr),
                           strerror(retval));
              free(next_hop_dev);
              return 1;
          }
      }
      free(next_hop_dev);
  
      /* Look up the MAC address of the next-hop IP address. */
      retval = netdev_arp_lookup(r->remote_netdev, next_hop_inaddr.s_addr,
                                 r->remote_mac);
      if (retval) {
          VLOG_DBG_RL(&rl, "cannot look up remote MAC address ("IP_FMT"): %s",
                      IP_ARGS(&next_hop_inaddr.s_addr), strerror(retval));
      }
  
      /* If we don't have a MAC address, then refresh quickly, since we probably
       * will get a MAC address soon (via ARP).  Otherwise, we can afford to wait
       * a little while. */
      return eth_addr_is_zero(r->remote_mac) ? 1 : 10;
  }
  
  static bool
  refresh_remotes(struct in_band *ib)
  {
      struct in_band_remote *r;
      bool any_changes;
  
      if (time_now() < ib->next_remote_refresh) {
          return false;
      }
  
      any_changes = false;
      ib->next_remote_refresh = TIME_MAX;
      for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
          uint8_t old_remote_mac[ETH_ADDR_LEN];
          time_t next_refresh;
  
          /* Save old MAC. */
          memcpy(old_remote_mac, r->remote_mac, ETH_ADDR_LEN);
  
          /* Refresh remote information. */
          next_refresh = refresh_remote(ib, r) + time_now();
          ib->next_remote_refresh = MIN(ib->next_remote_refresh, next_refresh);
  
          /* If the MAC changed, log the changes. */
          if (!eth_addr_equals(r->remote_mac, old_remote_mac)) {
              any_changes = true;
              if (!eth_addr_is_zero(r->remote_mac)
                  && !eth_addr_equals(r->last_remote_mac, r->remote_mac)) {
                  VLOG_DBG("remote MAC address changed from "ETH_ADDR_FMT
                           " to "ETH_ADDR_FMT,
                           ETH_ADDR_ARGS(r->last_remote_mac),
                           ETH_ADDR_ARGS(r->remote_mac));
                  memcpy(r->last_remote_mac, r->remote_mac, ETH_ADDR_LEN);
              }
          }
      }
  
      return any_changes;
  }
  
  /* Refreshes the MAC address of the local port into ib->local_mac, if it is due
   * for a refresh.  Returns true if anything changed, otherwise false.  */
  static bool
  refresh_local(struct in_band *ib)
  {
      uint8_t ea[ETH_ADDR_LEN];
      time_t now;
  
      now = time_now();
      if (now < ib->next_local_refresh) {
          return false;
      }
      ib->next_local_refresh = now + 1;
  
      if (netdev_get_etheraddr(ib->local_netdev, ea)
          || eth_addr_equals(ea, ib->local_mac)) {
          return false;
      }
  
      memcpy(ib->local_mac, ea, ETH_ADDR_LEN);
      return true;
  }
  
  /* Returns true if 'packet' should be sent to the local port regardless
   * of the flow table. */
  bool
  in_band_msg_in_hook(struct in_band *in_band, const struct flow *flow,
                      const struct ofpbuf *packet)
  {
      /* Regardless of how the flow table is configured, we want to be
       * able to see replies to our DHCP requests. */
      if (flow->dl_type == htons(ETH_TYPE_IP)
              && flow->nw_proto == IPPROTO_UDP
              && flow->tp_src == htons(DHCP_SERVER_PORT)
              && flow->tp_dst == htons(DHCP_CLIENT_PORT)
              && packet->l7) {
          struct dhcp_header *dhcp;
  
          dhcp = ofpbuf_at(packet, (char *)packet->l7 - (char *)packet->data,
                           sizeof *dhcp);
          if (!dhcp) {
              return false;
          }
  
          refresh_local(in_band);
          if (!eth_addr_is_zero(in_band->local_mac)
              && eth_addr_equals(dhcp->chaddr, in_band->local_mac)) {
              return true;
          }
      }
  
      return false;
  }
  
  /* Returns true if the rule that would match 'flow' with 'actions' is
   * allowed to be set up in the datapath. */
  bool
  in_band_rule_check(const struct flow *flow,
                     const struct nlattr *actions, size_t actions_len)
  {
      /* Don't allow flows that would prevent DHCP replies from being seen
       * by the local port. */
      if (flow->dl_type == htons(ETH_TYPE_IP)
              && flow->nw_proto == IPPROTO_UDP
              && flow->tp_src == htons(DHCP_SERVER_PORT)
              && flow->tp_dst == htons(DHCP_CLIENT_PORT)) {
          const struct nlattr *a;
          unsigned int left;
  
          NL_ATTR_FOR_EACH_UNSAFE (a, left, actions, actions_len) {
              if (nl_attr_type(a) == OVS_ACTION_ATTR_OUTPUT
                  && nl_attr_get_u32(a) == OVSP_LOCAL) {
                  return true;
              }
          }
          return false;
      }
  
      return true;
  }
  
  static void
  add_rule(struct in_band *ib, const struct cls_rule *cls_rule)
  {
      uint32_t hash = cls_rule_hash(cls_rule, 0);
      struct in_band_rule *rule;
  
      HMAP_FOR_EACH_WITH_HASH (rule, cls_rule.hmap_node, hash, &ib->rules) {
          if (cls_rule_equal(&rule->cls_rule, cls_rule)) {
              rule->op = ADD;
              return;
          }
      }
  
      rule = xmalloc(sizeof *rule);
      rule->cls_rule = *cls_rule;
      rule->op = ADD;
      hmap_insert(&ib->rules, &rule->cls_rule.hmap_node, hash);
  }
  
  static void
  update_rules(struct in_band *ib)
  {
      struct in_band_rule *ib_rule;
      struct in_band_remote *r;
      struct cls_rule rule;
  
      /* Mark all the existing rules for deletion.  (Afterward we will re-add any
       * rules that are still valid.) */
      HMAP_FOR_EACH (ib_rule, cls_rule.hmap_node, &ib->rules) {
          ib_rule->op = DELETE;
      }
  
      if (ib->n_remotes && !eth_addr_is_zero(ib->local_mac)) {
          /* (a) Allow DHCP requests sent from the local port. */
          cls_rule_init_catchall(&rule, IBR_FROM_LOCAL_DHCP);
          cls_rule_set_in_port(&rule, OFPP_LOCAL);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_IP));
          cls_rule_set_dl_src(&rule, ib->local_mac);
          cls_rule_set_nw_proto(&rule, IPPROTO_UDP);
          cls_rule_set_tp_src(&rule, htons(DHCP_CLIENT_PORT));
          cls_rule_set_tp_dst(&rule, htons(DHCP_SERVER_PORT));
          add_rule(ib, &rule);
  
          /* (b) Allow ARP replies to the local port's MAC address. */
          cls_rule_init_catchall(&rule, IBR_TO_LOCAL_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_dl_dst(&rule, ib->local_mac);
          cls_rule_set_nw_proto(&rule, ARP_OP_REPLY);
          add_rule(ib, &rule);
  
          /* (c) Allow ARP requests from the local port's MAC address.  */
          cls_rule_init_catchall(&rule, IBR_FROM_LOCAL_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_dl_src(&rule, ib->local_mac);
          cls_rule_set_nw_proto(&rule, ARP_OP_REQUEST);
          add_rule(ib, &rule);
      }
  
      for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
          const uint8_t *remote_mac = r->remote_mac;
  
          if (eth_addr_is_zero(remote_mac)) {
              continue;
          }
  
          /* (d) Allow ARP replies to the next hop's MAC address. */
          cls_rule_init_catchall(&rule, IBR_TO_NEXT_HOP_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_dl_dst(&rule, remote_mac);
          cls_rule_set_nw_proto(&rule, ARP_OP_REPLY);
          add_rule(ib, &rule);
  
          /* (e) Allow ARP requests from the next hop's MAC address. */
          cls_rule_init_catchall(&rule, IBR_FROM_NEXT_HOP_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_dl_src(&rule, remote_mac);
          cls_rule_set_nw_proto(&rule, ARP_OP_REQUEST);
          add_rule(ib, &rule);
      }
  
      for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
          const struct sockaddr_in *a = &r->remote_addr;
  
          /* (f) Allow ARP replies containing the remote's IP address as a
           * target. */
          cls_rule_init_catchall(&rule, IBR_TO_REMOTE_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_nw_proto(&rule, ARP_OP_REPLY);
          cls_rule_set_nw_dst(&rule, a->sin_addr.s_addr);
          add_rule(ib, &rule);
  
          /* (g) Allow ARP requests containing the remote's IP address as a
           * source. */
          cls_rule_init_catchall(&rule, IBR_FROM_REMOTE_ARP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_ARP));
          cls_rule_set_nw_proto(&rule, ARP_OP_REQUEST);
          cls_rule_set_nw_src(&rule, a->sin_addr.s_addr);
          add_rule(ib, &rule);
  
          /* (h) Allow TCP traffic to the remote's IP and port. */
          cls_rule_init_catchall(&rule, IBR_TO_REMOTE_TCP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_IP));
          cls_rule_set_nw_proto(&rule, IPPROTO_TCP);
          cls_rule_set_nw_dst(&rule, a->sin_addr.s_addr);
          cls_rule_set_tp_dst(&rule, a->sin_port);
          add_rule(ib, &rule);
  
          /* (i) Allow TCP traffic from the remote's IP and port. */
          cls_rule_init_catchall(&rule, IBR_FROM_REMOTE_TCP);
          cls_rule_set_dl_type(&rule, htons(ETH_TYPE_IP));
          cls_rule_set_nw_proto(&rule, IPPROTO_TCP);
          cls_rule_set_nw_src(&rule, a->sin_addr.s_addr);
          cls_rule_set_tp_src(&rule, a->sin_port);
          add_rule(ib, &rule);
      }
  }
  
  /* Updates the OpenFlow flow table for the current state of in-band control.
   * Returns true ordinarily.  Returns false if no remotes are configured on 'ib'
   * and 'ib' doesn't have any rules left to remove from the OpenFlow flow
   * table.  Thus, a false return value means that the caller can destroy 'ib'
   * without leaving extra flows hanging around in the flow table. */
  bool
  in_band_run(struct in_band *ib)
  {
      struct {
          struct nx_action_set_queue nxsq;
          union ofp_action oa;
      } actions;
      const void *a;
      size_t na;
  
      struct in_band_rule *rule, *next;
  
      memset(&actions, 0, sizeof actions);
      actions.oa.output.type = htons(OFPAT_OUTPUT);
      actions.oa.output.len = htons(sizeof actions.oa);
      actions.oa.output.port = htons(OFPP_NORMAL);
      actions.oa.output.max_len = htons(0);
      if (ib->queue_id < 0) {
          a = &actions.oa;
          na = sizeof actions.oa / sizeof(union ofp_action);
      } else {
          actions.nxsq.type = htons(OFPAT_VENDOR);
          actions.nxsq.len = htons(sizeof actions.nxsq);
          actions.nxsq.vendor = htonl(NX_VENDOR_ID);
          actions.nxsq.subtype = htons(NXAST_SET_QUEUE);
          actions.nxsq.queue_id = htonl(ib->queue_id);
          a = &actions;
          na = sizeof actions / sizeof(union ofp_action);
      }
  
      refresh_local(ib);
      refresh_remotes(ib);
  
      update_rules(ib);
  
      HMAP_FOR_EACH_SAFE (rule, next, cls_rule.hmap_node, &ib->rules) {
          switch (rule->op) {
          case ADD:
              ofproto_add_flow(ib->ofproto, &rule->cls_rule, a, na);
              break;
  
          case DELETE:
              if (ofproto_delete_flow(ib->ofproto, &rule->cls_rule)) {
                  /* ofproto doesn't have the rule anymore so there's no reason
                   * for us to track it any longer. */
                  hmap_remove(&ib->rules, &rule->cls_rule.hmap_node);
                  free(rule);
              }
              break;
          }
      }
  
      return ib->n_remotes || !hmap_is_empty(&ib->rules);
  }
  
  void
  in_band_wait(struct in_band *in_band)
  {
      long long int wakeup
              = MIN(in_band->next_remote_refresh, in_band->next_local_refresh);
      poll_timer_wait_until(wakeup * 1000);
  }
  
  int
  in_band_create(struct ofproto *ofproto, const char *local_name,
                 struct in_band **in_bandp)
  {
      struct in_band *in_band;
      struct netdev *local_netdev;
      int error;
  
      *in_bandp = NULL;
      error = netdev_open(local_name, "system", &local_netdev);
      if (error) {
          VLOG_ERR("failed to initialize in-band control: cannot open "
                   "datapath local port %s (%s)", local_name, strerror(error));
          return error;
      }
  
      in_band = xzalloc(sizeof *in_band);
      in_band->ofproto = ofproto;
      in_band->queue_id = -1;
      in_band->next_remote_refresh = TIME_MIN;
      in_band->next_local_refresh = TIME_MIN;
      in_band->local_netdev = local_netdev;
      hmap_init(&in_band->rules);
  
      *in_bandp = in_band;
  
      return 0;
  }
  
  void
  in_band_destroy(struct in_band *ib)
  {
      if (ib) {
          struct in_band_rule *rule, *next;
  
          HMAP_FOR_EACH_SAFE (rule, next, cls_rule.hmap_node, &ib->rules) {
              hmap_remove(&ib->rules, &rule->cls_rule.hmap_node);
              free(rule);
          }
          hmap_destroy(&ib->rules);
          in_band_set_remotes(ib, NULL, 0);
          netdev_close(ib->local_netdev);
          free(ib);
      }
  }
  
  static bool
  any_addresses_changed(struct in_band *ib,
                        const struct sockaddr_in *addresses, size_t n)
  {
      size_t i;
  
      if (n != ib->n_remotes) {
          return true;
      }
  
      for (i = 0; i < n; i++) {
          const struct sockaddr_in *old = &ib->remotes[i].remote_addr;
          const struct sockaddr_in *new = &addresses[i];
  
          if (old->sin_addr.s_addr != new->sin_addr.s_addr ||
              old->sin_port != new->sin_port) {
              return true;
          }
      }
  
      return false;
  }
  
  void
  in_band_set_remotes(struct in_band *ib,
                      const struct sockaddr_in *addresses, size_t n)
  {
      size_t i;
  
      if (!any_addresses_changed(ib, addresses, n)) {
          return;
      }
  
      /* Clear old remotes. */
      for (i = 0; i < ib->n_remotes; i++) {
          netdev_close(ib->remotes[i].remote_netdev);
      }
      free(ib->remotes);
  
      /* Set up new remotes. */
      ib->remotes = n ? xzalloc(n * sizeof *ib->remotes) : NULL;
      ib->n_remotes = n;
      for (i = 0; i < n; i++) {
          ib->remotes[i].remote_addr = addresses[i];
      }
  
      /* Force refresh in next call to in_band_run(). */
      ib->next_remote_refresh = TIME_MIN;
  }
  
  /* Sets the OpenFlow queue used by flows set up by 'ib' to 'queue_id'.  If
   * 'queue_id' is negative, 'ib' will not set any queue (which is also the
   * default). */
  void
  in_band_set_queue(struct in_band *ib, int queue_id)
  {
      ib->queue_id = queue_id;
  }
  
  