Factor out fixed/1-1 processing from vxlnat_vxlan_one(), paving way for
future processing types.
Initial definitions of NAT flows.

*** 67,84 ****
                  vxlnat_rule_free(vxnr);                         \
  }
  extern void vxlnat_rule_free(vxlnat_rule_t *);
  
  /*
   * 1-1 IP mapping.
   */
  typedef struct vxlnat_fixed_s {
          avl_node_t vxnf_treenode;
!         in6_addr_t vxnf_addr;   /* XXX KEBE ASKS - must it match to a rule? */
          in6_addr_t vxnf_pubaddr; /* External IP. */
          struct vxlnat_vnet_s *vxnf_vnet;
!         ire_t *vxnf_ire;        /* Should be a local IRE from the ftable. */
          struct vxlnat_remote_s *vxnf_remote;
          uint8_t vxnf_myether[ETHERADDRL];
          uint16_t vxnf_vlanid;   /* Stored in network order for quick xmit. */
          uint32_t vxnf_refcount;
          boolean_t vxnf_clear_router;    /* XXX KEBE SAYS CHEESY HACK */
--- 67,114 ----
                  vxlnat_rule_free(vxnr);                         \
  }
  extern void vxlnat_rule_free(vxlnat_rule_t *);
  
  /*
+  * NAT FLOWS.  These are per-vnet, and keyed/searched by:
+  * <inner-IP-source,IP-dest,inner-source-port,dest-port,protocol>.
+  * They will be tied-to/part-of
+  */
+ typedef struct vxlnat_flow_s {
+         avl_node_t vxnfl_treenode;
+         /*
+          * I'm guessing that dst varies more than src.  Also
+          * the plan is for the comparitor function to bcmp() both
+          * of these as one call for IPv6 (if we ever get to that..).
+          */
+         in6_addr_t vxnfl_dst;
+         in6_addr_t vxnfl_src;   /* INNER source address. */
+         uint32_t vxnfl_ports;
+         uint8_t vxnfl_protocol;
+         uint8_t vxnfl_isv4 : 1, /* Will save us 12 bytes of compares... */
+                 vxlfl_reserved1 : 7;
+         conn_t *vxnfl_connp;    /* Question - embed instead? */
+         vxlnat_rule_t *vxnfl_rule; /* Refhold to rule that generated me. */
+ } vxlnat_flow_t;
+ /* Exploit endianisms, maintain network order... */
+ #ifdef _BIG_ENDIAN
+ #define VXNFL_SPORT(ports) (uint16_t)((ports) >> 16) /* Unsigned all around. */
+ #define VXNFL_DPORT(ports) ((ports) & 0xFFFF)
+ #else
+ #define VXNFL_SPORT(ports) ((ports) & 0xFFFF)
+ #define VXNFL_DPORT(ports) (uint16_t)((ports) >> 16) /* Unsigned all around. */
+ #endif
+ 
+ /*
   * 1-1 IP mapping.
   */
  typedef struct vxlnat_fixed_s {
          avl_node_t vxnf_treenode;
!         in6_addr_t vxnf_addr;   /* For now it needn't match to a rule. */
          in6_addr_t vxnf_pubaddr; /* External IP. */
          struct vxlnat_vnet_s *vxnf_vnet;
!         ire_t *vxnf_ire;        /* Should be an IRE_LOCAL from the ftable. */
          struct vxlnat_remote_s *vxnf_remote;
          uint8_t vxnf_myether[ETHERADDRL];
          uint16_t vxnf_vlanid;   /* Stored in network order for quick xmit. */
          uint32_t vxnf_refcount;
          boolean_t vxnf_clear_router;    /* XXX KEBE SAYS CHEESY HACK */
*** 98,108 ****
  /*
   * REMOTE VXLAN destinations.
   */
  typedef struct vxlnat_remote_s {
          avl_node_t vxnrem_treenode;
!         in6_addr_t vxnrem_addr; /* Same prefix as one in rule. */
          in6_addr_t vxnrem_uaddr; /* Underlay VXLAN destination. */
          struct vxlnat_vnet_s *vxnrem_vnet;      /* Reference-held. */
          uint32_t vxnrem_refcount;
          uint8_t vxnrem_ether[ETHERADDRL];
          uint16_t vxnrem_vlan;
--- 128,138 ----
  /*
   * REMOTE VXLAN destinations.
   */
  typedef struct vxlnat_remote_s {
          avl_node_t vxnrem_treenode;
!         in6_addr_t vxnrem_addr; /* Same prefix as one in rule, or fixed addr. */
          in6_addr_t vxnrem_uaddr; /* Underlay VXLAN destination. */
          struct vxlnat_vnet_s *vxnrem_vnet;      /* Reference-held. */
          uint32_t vxnrem_refcount;
          uint8_t vxnrem_ether[ETHERADDRL];
          uint16_t vxnrem_vlan;
*** 131,155 ****
   */
  typedef struct vxlnat_vnet_s {
          avl_node_t vxnv_treenode;
          /*
           * 1-1 IP mappings. (1st lookup for an in-to-out packet.)
!          * Will map to SOMETHING in IP.
!          * XXX KEBE ASKS - conn_t or something else TBD?!
           */
          krwlock_t vxnv_fixed_lock;
          avl_tree_t vxnv_fixed_ips;
          /*
           * NAT flows. (2nd lookup for an in-to-out packet.)
           * These are also conn_ts with outer-packet fields for out-to-in
           * matches against a conn_t.
           */
!         krwlock_t vxnv_flow_lock;
!         avl_tree_t vxnv_flows;
          /* NAT rules. (3rd lookup for an in-to-out packet.) */
          kmutex_t vxnv_rule_lock;
          list_t vxnv_rules;
          /*
           * Internal-network remote-nodes. (only lookup for out-to-in packet.)
           * Entries here are also refheld by 1-1s or NAT flows.
           */
          kmutex_t vxnv_remote_lock;
--- 161,190 ----
   */
  typedef struct vxlnat_vnet_s {
          avl_node_t vxnv_treenode;
          /*
           * 1-1 IP mappings. (1st lookup for an in-to-out packet.)
!          * Will map to an IRE_LOCAL in IP.
           */
          krwlock_t vxnv_fixed_lock;
          avl_tree_t vxnv_fixed_ips;
+ 
          /*
           * NAT flows. (2nd lookup for an in-to-out packet.)
           * These are also conn_ts with outer-packet fields for out-to-in
           * matches against a conn_t.
+          *
+          * NOTE: We're going to keep a separate tree for inner IPv6 NAT, if
+          * we ever need it.
           */
!         krwlock_t vxnv_flowv4_lock;
!         avl_tree_t vxnv_flows_v4;
! 
          /* NAT rules. (3rd lookup for an in-to-out packet.) */
          kmutex_t vxnv_rule_lock;
          list_t vxnv_rules;
+ 
          /*
           * Internal-network remote-nodes. (only lookup for out-to-in packet.)
           * Entries here are also refheld by 1-1s or NAT flows.
           */
          kmutex_t vxnv_remote_lock;