Diff: lwip/core/netif.c

Revision:

12:8dc6b255af6c

Parent:

11:da4498f591ee

--- a/lwip/core/netif.c	Thu Aug 05 15:01:33 2010 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,752 +0,0 @@
-/**
- * @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_impl.h"
-#include "lwip/snmp.h"
-#include "lwip/igmp.h"
-#include "netif/etharp.h"
-#include "lwip/stats.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) do{ if (n->status_callback) { (n->status_callback)(n); }}while(0)
-#else
-#define NETIF_STATUS_CALLBACK(n)
-#endif /* LWIP_NETIF_STATUS_CALLBACK */ 
-
-#if LWIP_NETIF_LINK_CALLBACK
-#define NETIF_LINK_CALLBACK(n) do{ if (n->link_callback) { (n->link_callback)(n); }}while(0)
-#else
-#define NETIF_LINK_CALLBACK(n)
-#endif /* LWIP_NETIF_LINK_CALLBACK */ 
-
-struct netif *netif_list;
-struct netif *netif_default;
-
-#if LWIP_HAVE_LOOPIF
-static struct netif loop_netif;
-
-/**
- * Initialize a lwip network interface structure for a loopback interface
- *
- * @param netif the lwip network interface structure for this loopif
- * @return ERR_OK if the loopif is initialized
- *         ERR_MEM if private data couldn't be allocated
- */
-static err_t
-netif_loopif_init(struct netif *netif)
-{
-  /* initialize the snmp variables and counters inside the struct netif
-   * ifSpeed: no assumption can be made!
-   */
-  NETIF_INIT_SNMP(netif, snmp_ifType_softwareLoopback, 0);
-
-  netif->name[0] = 'l';
-  netif->name[1] = 'o';
-  netif->output = netif_loop_output;
-  return ERR_OK;
-}
-#endif /* LWIP_HAVE_LOOPIF */
-
-void
-netif_init(void)
-{
-#if LWIP_HAVE_LOOPIF
-  ip_addr_t loop_ipaddr, loop_netmask, loop_gw;
-  IP4_ADDR(&loop_gw, 127,0,0,1);
-  IP4_ADDR(&loop_ipaddr, 127,0,0,1);
-  IP4_ADDR(&loop_netmask, 255,0,0,0);
-
-#if NO_SYS
-  netif_add(&loop_netif, &loop_ipaddr, &loop_netmask, &loop_gw, NULL, netif_loopif_init, ip_input);
-#else  /* NO_SYS */
-  netif_add(&loop_netif, &loop_ipaddr, &loop_netmask, &loop_gw, NULL, netif_loopif_init, tcpip_input);
-#endif /* NO_SYS */
-  netif_set_up(&loop_netif);
-
-#endif /* LWIP_HAVE_LOOPIF */
-}
-
-/**
- * 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, ip_addr_t *ipaddr, ip_addr_t *netmask,
-  ip_addr_t *gw, void *state, netif_init_fn init, netif_input_fn input)
-{
-  static u8_t netifnum = 0;
-
-  LWIP_ASSERT("No init function given", init != NULL);
-
-  /* reset new interface configuration state */
-  ip_addr_set_zero(&netif->ip_addr);
-  ip_addr_set_zero(&netif->netmask);
-  ip_addr_set_zero(&netif->gw);
-  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, ip_addr_t *ipaddr, ip_addr_t *netmask,
-    ip_addr_t *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 */
-  if (netif_is_up(netif)) {
-    /* set netif down before removing (call callback function) */
-    netif_set_down(netif);
-  }
-
-  snmp_delete_ipaddridx_tree(netif);
-
-  /*  is it the first netif? */
-  if (netif_list == netif) {
-    netif_list = netif->next;
-  } 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;
-        break;
-      }
-    }
-    if (tmpNetif == NULL)
-      return; /*  we didn't find any netif today */
-  }
-  snmp_dec_iflist();
-  /* 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, ip_addr_t *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))
-#if LWIP_AUTOIP
-        /* connections to link-local addresses must persist (RFC3927 ch. 1.9) */
-        && !ip_addr_islinklocal(&(pcb->local_ip))
-#endif /* LWIP_AUTOIP */
-        ) {
-        /* 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_16(&netif->ip_addr),
-    ip4_addr2_16(&netif->ip_addr),
-    ip4_addr3_16(&netif->ip_addr),
-    ip4_addr4_16(&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, ip_addr_t *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_16(&netif->gw),
-    ip4_addr2_16(&netif->gw),
-    ip4_addr3_16(&netif->gw),
-    ip4_addr4_16(&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, ip_addr_t *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_16(&netif->netmask),
-    ip4_addr2_16(&netif->netmask),
-    ip4_addr3_16(&netif->netmask),
-    ip4_addr4_16(&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_STATUS_CALLBACK(netif);
-
-    if (netif->flags & NETIF_FLAG_LINK_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 */
-    }
-  }
-}
-
-/**
- * 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_STATUS_CALLBACK(netif);
-  }
-}
-
-#if LWIP_NETIF_STATUS_CALLBACK
-/**
- * Set callback to be called when interface is brought up/down
- */
-void netif_set_status_callback(struct netif *netif, netif_status_callback_fn status_callback)
-{
-  if (netif) {
-    netif->status_callback = status_callback;
-  }
-}
-#endif /* LWIP_NETIF_STATUS_CALLBACK */
-
-/**
- * Called by a driver when its link goes up
- */
-void netif_set_link_up(struct netif *netif )
-{
-  if (!(netif->flags & NETIF_FLAG_LINK_UP)) {
-    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 )
-{
-  if (netif->flags & NETIF_FLAG_LINK_UP) {
-    netif->flags &= ~NETIF_FLAG_LINK_UP;
-    NETIF_LINK_CALLBACK(netif);
-  }
-}
-
-#if LWIP_NETIF_LINK_CALLBACK
-/**
- * Set callback to be called when link is brought up/down
- */
-void netif_set_link_callback(struct netif *netif, netif_status_callback_fn link_callback)
-{
-  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,
-       ip_addr_t *ipaddr)
-{
-  struct pbuf *r;
-  err_t err;
-  struct pbuf *last;
-#if LWIP_LOOPBACK_MAX_PBUFS
-  u8_t clen = 0;
-#endif /* LWIP_LOOPBACK_MAX_PBUFS */
-  /* If we have a loopif, SNMP counters are adjusted for it,
-   * if not they are adjusted for 'netif'. */
-#if LWIP_SNMP
-#if LWIP_HAVE_LOOPIF
-  struct netif *stats_if = &loop_netif;
-#else /* LWIP_HAVE_LOOPIF */
-  struct netif *stats_if = netif;
-#endif /* LWIP_HAVE_LOOPIF */
-#endif /* LWIP_SNMP */
-  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) {
-    LINK_STATS_INC(link.memerr);
-    LINK_STATS_INC(link.drop);
-    snmp_inc_ifoutdiscards(stats_if);
-    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);
-    LINK_STATS_INC(link.memerr);
-    LINK_STATS_INC(link.drop);
-    snmp_inc_ifoutdiscards(stats_if);
-    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);
-    LINK_STATS_INC(link.memerr);
-    LINK_STATS_INC(link.drop);
-    snmp_inc_ifoutdiscards(stats_if);
-    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);
-
-  LINK_STATS_INC(link.xmit);
-  snmp_add_ifoutoctets(stats_if, p->tot_len);
-  snmp_inc_ifoutucastpkts(stats_if);
-
-#if LWIP_NETIF_LOOPBACK_MULTITHREADING
-  /* For multithreading environment, schedule a call to netif_poll */
-  tcpip_callback((tcpip_callback_fn)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;
-  /* If we have a loopif, SNMP counters are adjusted for it,
-   * if not they are adjusted for 'netif'. */
-#if LWIP_SNMP
-#if LWIP_HAVE_LOOPIF
-  struct netif *stats_if = &loop_netif;
-#else /* LWIP_HAVE_LOOPIF */
-  struct netif *stats_if = netif;
-#endif /* LWIP_HAVE_LOOPIF */
-#endif /* LWIP_SNMP */
-  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) {
-      LINK_STATS_INC(link.recv);
-      snmp_add_ifinoctets(stats_if, in->tot_len);
-      snmp_inc_ifinucastpkts(stats_if);
-      /* 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 */