text: /**
   * @file
   * lwIP network interface abstraction
   *
   */
  
  /*
   * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
   * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
   * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   * OF SUCH DAMAGE.
   *
   * This file is part of the lwIP TCP/IP stack.
   *
   * Author: Adam Dunkels <adam@sics.se>
   *
   */
  
  #include "lwip/opt.h"
  
  #include "lwip/def.h"
  #include "lwip/ip_addr.h"
  #include "lwip/netif.h"
  #include "lwip/tcp.h"
  #include "lwip/snmp.h"
  #include "lwip/igmp.h"
  #include "netif/etharp.h"
  #if ENABLE_LOOPBACK
  #include "lwip/sys.h"
  #if LWIP_NETIF_LOOPBACK_MULTITHREADING
  #include "lwip/tcpip.h"
  #endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
  #endif /* ENABLE_LOOPBACK */
  
  #if LWIP_AUTOIP
  #include "lwip/autoip.h"
  #endif /* LWIP_AUTOIP */
  #if LWIP_DHCP
  #include "lwip/dhcp.h"
  #endif /* LWIP_DHCP */
  
  #if LWIP_NETIF_STATUS_CALLBACK
  #define NETIF_STATUS_CALLBACK(n) { if (n->status_callback) (n->status_callback)(n); }
  #else
  #define NETIF_STATUS_CALLBACK(n) { /* NOP */ }
  #endif /* LWIP_NETIF_STATUS_CALLBACK */ 
  
  #if LWIP_NETIF_LINK_CALLBACK
  #define NETIF_LINK_CALLBACK(n) { if (n->link_callback) (n->link_callback)(n); }
  #else
  #define NETIF_LINK_CALLBACK(n) { /* NOP */ }
  #endif /* LWIP_NETIF_LINK_CALLBACK */ 
  
  struct netif *netif_list;
  struct netif *netif_default;
  
  /**
   * Add a network interface to the list of lwIP netifs.
   *
   * @param netif a pre-allocated netif structure
   * @param ipaddr IP address for the new netif
   * @param netmask network mask for the new netif
   * @param gw default gateway IP address for the new netif
   * @param state opaque data passed to the new netif
   * @param init callback function that initializes the interface
   * @param input callback function that is called to pass
   * ingress packets up in the protocol layer stack.
   *
   * @return netif, or NULL if failed.
   */
  struct netif *
  netif_add(struct netif *netif, struct ip_addr *ipaddr, struct ip_addr *netmask,
    struct ip_addr *gw,
    void *state,
    err_t (* init)(struct netif *netif),
    err_t (* input)(struct pbuf *p, struct netif *netif))
  {
    static u8_t netifnum = 0;
  
    /* reset new interface configuration state */
    netif->ip_addr.addr = 0;
    netif->netmask.addr = 0;
    netif->gw.addr = 0;
    netif->flags = 0;
  #if LWIP_DHCP
    /* netif not under DHCP control by default */
    netif->dhcp = NULL;
  #endif /* LWIP_DHCP */
  #if LWIP_AUTOIP
    /* netif not under AutoIP control by default */
    netif->autoip = NULL;
  #endif /* LWIP_AUTOIP */
  #if LWIP_NETIF_STATUS_CALLBACK
    netif->status_callback = NULL;
  #endif /* LWIP_NETIF_STATUS_CALLBACK */
  #if LWIP_NETIF_LINK_CALLBACK
    netif->link_callback = NULL;
  #endif /* LWIP_NETIF_LINK_CALLBACK */
  #if LWIP_IGMP
    netif->igmp_mac_filter = NULL;
  #endif /* LWIP_IGMP */
  #if ENABLE_LOOPBACK
    netif->loop_first = NULL;
    netif->loop_last = NULL;
  #endif /* ENABLE_LOOPBACK */
  
    /* remember netif specific state information data */
    netif->state = state;
    netif->num = netifnum++;
    netif->input = input;
  #if LWIP_NETIF_HWADDRHINT
    netif->addr_hint = NULL;
  #endif /* LWIP_NETIF_HWADDRHINT*/
  #if ENABLE_LOOPBACK && LWIP_LOOPBACK_MAX_PBUFS
    netif->loop_cnt_current = 0;
  #endif /* ENABLE_LOOPBACK && LWIP_LOOPBACK_MAX_PBUFS */
  
    netif_set_addr(netif, ipaddr, netmask, gw);
  
    /* call user specified initialization function for netif */
    if (init(netif) != ERR_OK) {
      return NULL;
    }
  
    /* add this netif to the list */
    netif->next = netif_list;
    netif_list = netif;
    snmp_inc_iflist();
  
  #if LWIP_IGMP
    /* start IGMP processing */
    if (netif->flags & NETIF_FLAG_IGMP) {
      igmp_start( netif);
    }
  #endif /* LWIP_IGMP */
  
    LWIP_DEBUGF(NETIF_DEBUG, ("netif: added interface %c%c IP addr ",
      netif->name[0], netif->name[1]));
    ip_addr_debug_print(NETIF_DEBUG, ipaddr);
    LWIP_DEBUGF(NETIF_DEBUG, (" netmask "));
    ip_addr_debug_print(NETIF_DEBUG, netmask);
    LWIP_DEBUGF(NETIF_DEBUG, (" gw "));
    ip_addr_debug_print(NETIF_DEBUG, gw);
    LWIP_DEBUGF(NETIF_DEBUG, ("\n"));
    return netif;
  }
  
  /**
   * Change IP address configuration for a network interface (including netmask
   * and default gateway).
   *
   * @param netif the network interface to change
   * @param ipaddr the new IP address
   * @param netmask the new netmask
   * @param gw the new default gateway
   */
  void
  netif_set_addr(struct netif *netif, struct ip_addr *ipaddr, struct ip_addr *netmask,
      struct ip_addr *gw)
  {
    netif_set_ipaddr(netif, ipaddr);
    netif_set_netmask(netif, netmask);
    netif_set_gw(netif, gw);
  }
  
  /**
   * Remove a network interface from the list of lwIP netifs.
   *
   * @param netif the network interface to remove
   */
  void netif_remove(struct netif * netif)
  {
    if ( netif == NULL ) return;
  
  #if LWIP_IGMP
    /* stop IGMP processing */
    if (netif->flags & NETIF_FLAG_IGMP) {
      igmp_stop( netif);
    }
  #endif /* LWIP_IGMP */
  
    snmp_delete_ipaddridx_tree(netif);
  
    /*  is it the first netif? */
    if (netif_list == netif) {
      netif_list = netif->next;
      snmp_dec_iflist();
    }
    else {
      /*  look for netif further down the list */
      struct netif * tmpNetif;
      for (tmpNetif = netif_list; tmpNetif != NULL; tmpNetif = tmpNetif->next) {
        if (tmpNetif->next == netif) {
          tmpNetif->next = netif->next;
          snmp_dec_iflist();
          break;
        }
      }
      if (tmpNetif == NULL)
        return; /*  we didn't find any netif today */
    }
    /* this netif is default? */
    if (netif_default == netif)
      /* reset default netif */
      netif_set_default(NULL);
    LWIP_DEBUGF( NETIF_DEBUG, ("netif_remove: removed netif\n") );
  }
  
  /**
   * Find a network interface by searching for its name
   *
   * @param name the name of the netif (like netif->name) plus concatenated number
   * in ascii representation (e.g. 'en0')
   */
  struct netif *
  netif_find(char *name)
  {
    struct netif *netif;
    u8_t num;
  
    if (name == NULL) {
      return NULL;
    }
  
    num = name[2] - '0';
  
    for(netif = netif_list; netif != NULL; netif = netif->next) {
      if (num == netif->num &&
         name[0] == netif->name[0] &&
         name[1] == netif->name[1]) {
        LWIP_DEBUGF(NETIF_DEBUG, ("netif_find: found %c%c\n", name[0], name[1]));
        return netif;
      }
    }
    LWIP_DEBUGF(NETIF_DEBUG, ("netif_find: didn't find %c%c\n", name[0], name[1]));
    return NULL;
  }
  
  /**
   * Change the IP address of a network interface
   *
   * @param netif the network interface to change
   * @param ipaddr the new IP address
   *
   * @note call netif_set_addr() if you also want to change netmask and
   * default gateway
   */
  void
  netif_set_ipaddr(struct netif *netif, struct ip_addr *ipaddr)
  {
    /* TODO: Handling of obsolete pcbs */
    /* See:  http://mail.gnu.org/archive/html/lwip-users/2003-03/msg00118.html */
  #if LWIP_TCP
    struct tcp_pcb *pcb;
    struct tcp_pcb_listen *lpcb;
  
    /* address is actually being changed? */
    if ((ip_addr_cmp(ipaddr, &(netif->ip_addr))) == 0)
    {
      /* extern struct tcp_pcb *tcp_active_pcbs; defined by tcp.h */
      LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_STATE, ("netif_set_ipaddr: netif address being changed\n"));
      pcb = tcp_active_pcbs;
      while (pcb != NULL) {
        /* PCB bound to current local interface address? */
        if (ip_addr_cmp(&(pcb->local_ip), &(netif->ip_addr))) {
          /* this connection must be aborted */
          struct tcp_pcb *next = pcb->next;
          LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_STATE, ("netif_set_ipaddr: aborting TCP pcb %p\n", (void *)pcb));
          tcp_abort(pcb);
          pcb = next;
        } else {
          pcb = pcb->next;
        }
      }
      for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
        /* PCB bound to current local interface address? */
        if ((!(ip_addr_isany(&(lpcb->local_ip)))) &&
            (ip_addr_cmp(&(lpcb->local_ip), &(netif->ip_addr)))) {
          /* The PCB is listening to the old ipaddr and
           * is set to listen to the new one instead */
          ip_addr_set(&(lpcb->local_ip), ipaddr);
        }
      }
    }
  #endif
    snmp_delete_ipaddridx_tree(netif);
    snmp_delete_iprteidx_tree(0,netif);
    /* set new IP address to netif */
    ip_addr_set(&(netif->ip_addr), ipaddr);
    snmp_insert_ipaddridx_tree(netif);
    snmp_insert_iprteidx_tree(0,netif);
  
    LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: IP address of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
      netif->name[0], netif->name[1],
      ip4_addr1(&netif->ip_addr),
      ip4_addr2(&netif->ip_addr),
      ip4_addr3(&netif->ip_addr),
      ip4_addr4(&netif->ip_addr)));
  }
  
  /**
   * Change the default gateway for a network interface
   *
   * @param netif the network interface to change
   * @param gw the new default gateway
   *
   * @note call netif_set_addr() if you also want to change ip address and netmask
   */
  void
  netif_set_gw(struct netif *netif, struct ip_addr *gw)
  {
    ip_addr_set(&(netif->gw), gw);
    LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: GW address of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
      netif->name[0], netif->name[1],
      ip4_addr1(&netif->gw),
      ip4_addr2(&netif->gw),
      ip4_addr3(&netif->gw),
      ip4_addr4(&netif->gw)));
  }
  
  /**
   * Change the netmask of a network interface
   *
   * @param netif the network interface to change
   * @param netmask the new netmask
   *
   * @note call netif_set_addr() if you also want to change ip address and
   * default gateway
   */
  void
  netif_set_netmask(struct netif *netif, struct ip_addr *netmask)
  {
    snmp_delete_iprteidx_tree(0, netif);
    /* set new netmask to netif */
    ip_addr_set(&(netif->netmask), netmask);
    snmp_insert_iprteidx_tree(0, netif);
    LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: netmask of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
      netif->name[0], netif->name[1],
      ip4_addr1(&netif->netmask),
      ip4_addr2(&netif->netmask),
      ip4_addr3(&netif->netmask),
      ip4_addr4(&netif->netmask)));
  }
  
  /**
   * Set a network interface as the default network interface
   * (used to output all packets for which no specific route is found)
   *
   * @param netif the default network interface
   */
  void
  netif_set_default(struct netif *netif)
  {
    if (netif == NULL)
    {
      /* remove default route */
      snmp_delete_iprteidx_tree(1, netif);
    }
    else
    {
      /* install default route */
      snmp_insert_iprteidx_tree(1, netif);
    }
    netif_default = netif;
    LWIP_DEBUGF(NETIF_DEBUG, ("netif: setting default interface %c%c\n",
             netif ? netif->name[0] : '\'', netif ? netif->name[1] : '\''));
  }
  
  /**
   * Bring an interface up, available for processing
   * traffic.
   * 
   * @note: Enabling DHCP on a down interface will make it come
   * up once configured.
   * 
   * @see dhcp_start()
   */ 
  void netif_set_up(struct netif *netif)
  {
    if ( !(netif->flags & NETIF_FLAG_UP )) {
      netif->flags |= NETIF_FLAG_UP;
      
  #if LWIP_SNMP
      snmp_get_sysuptime(&netif->ts);
  #endif /* LWIP_SNMP */
  
      NETIF_LINK_CALLBACK(netif);
      NETIF_STATUS_CALLBACK(netif);
  
  #if LWIP_ARP
      /* For Ethernet network interfaces, we would like to send a "gratuitous ARP" */ 
      if (netif->flags & NETIF_FLAG_ETHARP) {
        etharp_gratuitous(netif);
      }
  #endif /* LWIP_ARP */
  
  #if LWIP_IGMP
      /* resend IGMP memberships */
      if (netif->flags & NETIF_FLAG_IGMP) {
        igmp_report_groups( netif);
      }
  #endif /* LWIP_IGMP */
    }
  }
  
  /**
   * Bring an interface down, disabling any traffic processing.
   *
   * @note: Enabling DHCP on a down interface will make it come
   * up once configured.
   * 
   * @see dhcp_start()
   */ 
  void netif_set_down(struct netif *netif)
  {
    if ( netif->flags & NETIF_FLAG_UP )
      {
        netif->flags &= ~NETIF_FLAG_UP;
  #if LWIP_SNMP
        snmp_get_sysuptime(&netif->ts);
  #endif
        
        NETIF_LINK_CALLBACK(netif);
        NETIF_STATUS_CALLBACK(netif);
      }
  }
  
  /**
   * Ask if an interface is up
   */ 
  u8_t netif_is_up(struct netif *netif)
  {
    return (netif->flags & NETIF_FLAG_UP)?1:0;
  }
  
  #if LWIP_NETIF_STATUS_CALLBACK
  /**
   * Set callback to be called when interface is brought up/down
   */
  void netif_set_status_callback(struct netif *netif, void (* status_callback)(struct netif *netif ))
  {
      if ( netif )
          netif->status_callback = status_callback;
  }
  #endif /* LWIP_NETIF_STATUS_CALLBACK */
  
  #if LWIP_NETIF_LINK_CALLBACK
  /**
   * Called by a driver when its link goes up
   */
  void netif_set_link_up(struct netif *netif )
  {
    netif->flags |= NETIF_FLAG_LINK_UP;
  
  #if LWIP_DHCP
    if (netif->dhcp) {
      dhcp_network_changed(netif);
    }
  #endif /* LWIP_DHCP */
  
  #if LWIP_AUTOIP
    if (netif->autoip) {
      autoip_network_changed(netif);
    }
  #endif /* LWIP_AUTOIP */
  
    if (netif->flags & NETIF_FLAG_UP) {
  #if LWIP_ARP
    /* For Ethernet network interfaces, we would like to send a "gratuitous ARP" */ 
    if (netif->flags & NETIF_FLAG_ETHARP) {
      etharp_gratuitous(netif);
    }
  #endif /* LWIP_ARP */
  
  #if LWIP_IGMP
      /* resend IGMP memberships */
      if (netif->flags & NETIF_FLAG_IGMP) {
        igmp_report_groups( netif);
      }
  #endif /* LWIP_IGMP */
    }
    NETIF_LINK_CALLBACK(netif);
  }
  
  /**
   * Called by a driver when its link goes down
   */
  void netif_set_link_down(struct netif *netif )
  {
    netif->flags &= ~NETIF_FLAG_LINK_UP;
    NETIF_LINK_CALLBACK(netif);
  }
  
  /**
   * Ask if a link is up
   */ 
  u8_t netif_is_link_up(struct netif *netif)
  {
    return (netif->flags & NETIF_FLAG_LINK_UP) ? 1 : 0;
  }
  
  /**
   * Set callback to be called when link is brought up/down
   */
  void netif_set_link_callback(struct netif *netif, void (* link_callback)(struct netif *netif ))
  {
    if (netif) {
      netif->link_callback = link_callback;
    }
  }
  #endif /* LWIP_NETIF_LINK_CALLBACK */
  
  #if ENABLE_LOOPBACK
  /**
   * Send an IP packet to be received on the same netif (loopif-like).
   * The pbuf is simply copied and handed back to netif->input.
   * In multithreaded mode, this is done directly since netif->input must put
   * the packet on a queue.
   * In callback mode, the packet is put on an internal queue and is fed to
   * netif->input by netif_poll().
   *
   * @param netif the lwip network interface structure
   * @param p the (IP) packet to 'send'
   * @param ipaddr the ip address to send the packet to (not used)
   * @return ERR_OK if the packet has been sent
   *         ERR_MEM if the pbuf used to copy the packet couldn't be allocated
   */
  err_t
  netif_loop_output(struct netif *netif, struct pbuf *p,
         struct ip_addr *ipaddr)
  {
    struct pbuf *r;
    err_t err;
    struct pbuf *last;
  #if LWIP_LOOPBACK_MAX_PBUFS
    u8_t clen = 0;
  #endif /* LWIP_LOOPBACK_MAX_PBUFS */
    SYS_ARCH_DECL_PROTECT(lev);
    LWIP_UNUSED_ARG(ipaddr);
  
    /* Allocate a new pbuf */
    r = pbuf_alloc(PBUF_LINK, p->tot_len, PBUF_RAM);
    if (r == NULL) {
      return ERR_MEM;
    }
  #if LWIP_LOOPBACK_MAX_PBUFS
    clen = pbuf_clen(r);
    /* check for overflow or too many pbuf on queue */
    if(((netif->loop_cnt_current + clen) < netif->loop_cnt_current) ||
      ((netif->loop_cnt_current + clen) > LWIP_LOOPBACK_MAX_PBUFS)) {
        pbuf_free(r);
        r = NULL;
        return ERR_MEM;
    }
    netif->loop_cnt_current += clen;
  #endif /* LWIP_LOOPBACK_MAX_PBUFS */
  
    /* Copy the whole pbuf queue p into the single pbuf r */
    if ((err = pbuf_copy(r, p)) != ERR_OK) {
      pbuf_free(r);
      r = NULL;
      return err;
    }
  
    /* Put the packet on a linked list which gets emptied through calling
       netif_poll(). */
  
    /* let last point to the last pbuf in chain r */
    for (last = r; last->next != NULL; last = last->next);
  
    SYS_ARCH_PROTECT(lev);
    if(netif->loop_first != NULL) {
      LWIP_ASSERT("if first != NULL, last must also be != NULL", netif->loop_last != NULL);
      netif->loop_last->next = r;
      netif->loop_last = last;
    } else {
      netif->loop_first = r;
      netif->loop_last = last;
    }
    SYS_ARCH_UNPROTECT(lev);
  
  #if LWIP_NETIF_LOOPBACK_MULTITHREADING
    /* For multithreading environment, schedule a call to netif_poll */
    tcpip_callback((void (*)(void *))(netif_poll), netif);
  #endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
  
    return ERR_OK;
  }
  
  /**
   * Call netif_poll() in the main loop of your application. This is to prevent
   * reentering non-reentrant functions like tcp_input(). Packets passed to
   * netif_loop_output() are put on a list that is passed to netif->input() by
   * netif_poll().
   */
  void
  netif_poll(struct netif *netif)
  {
    struct pbuf *in;
    SYS_ARCH_DECL_PROTECT(lev);
  
    do {
      /* Get a packet from the list. With SYS_LIGHTWEIGHT_PROT=1, this is protected */
      SYS_ARCH_PROTECT(lev);
      in = netif->loop_first;
      if(in != NULL) {
        struct pbuf *in_end = in;
  #if LWIP_LOOPBACK_MAX_PBUFS
        u8_t clen = pbuf_clen(in);
        /* adjust the number of pbufs on queue */
        LWIP_ASSERT("netif->loop_cnt_current underflow",
          ((netif->loop_cnt_current - clen) < netif->loop_cnt_current));
        netif->loop_cnt_current -= clen;
  #endif /* LWIP_LOOPBACK_MAX_PBUFS */
        while(in_end->len != in_end->tot_len) {
          LWIP_ASSERT("bogus pbuf: len != tot_len but next == NULL!", in_end->next != NULL);
          in_end = in_end->next;
        }
        /* 'in_end' now points to the last pbuf from 'in' */
        if(in_end == netif->loop_last) {
          /* this was the last pbuf in the list */
          netif->loop_first = netif->loop_last = NULL;
        } else {
          /* pop the pbuf off the list */
          netif->loop_first = in_end->next;
          LWIP_ASSERT("should not be null since first != last!", netif->loop_first != NULL);
        }
        /* De-queue the pbuf from its successors on the 'loop_' list. */
        in_end->next = NULL;
      }
      SYS_ARCH_UNPROTECT(lev);
  
      if(in != NULL) {
        /* loopback packets are always IP packets! */
        if(ip_input(in, netif) != ERR_OK) {
          pbuf_free(in);
        }
        /* Don't reference the packet any more! */
        in = NULL;
      }
    /* go on while there is a packet on the list */
    } while(netif->loop_first != NULL);
  }
  
  #if !LWIP_NETIF_LOOPBACK_MULTITHREADING
  /**
   * Calls netif_poll() for every netif on the netif_list.
   */
  void
  netif_poll_all(void)
  {
    struct netif *netif = netif_list;
    /* loop through netifs */
    while (netif != NULL) {
      netif_poll(netif);
      /* proceed to next network interface */
      netif = netif->next;
    }
  }
  #endif /* !LWIP_NETIF_LOOPBACK_MULTITHREADING */
  #endif /* ENABLE_LOOPBACK */
  