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/**

 * @file

 * Implementation of raw protocol PCBs for low-level handling of

 * different types of protocols besides (or overriding) those

 * already available in lwIP.

 *

 */

/*

 * 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"

#if LWIP_RAW /* don't build if not configured for use in lwipopts.h */

#include "lwip/def.h"

#include "lwip/memp.h"

#include "lwip/inet.h"

#include "lwip/ip_addr.h"

#include "lwip/netif.h"

#include "lwip/raw.h"

#include "lwip/stats.h"

#include "lwip/snmp.h"

#include "arch/perf.h"

#include <string.h>

/** The list of RAW PCBs */

static struct raw_pcb *raw_pcbs;

/**

 * Determine if in incoming IP packet is covered by a RAW PCB

 * and if so, pass it to a user-provided receive callback function.

 *

 * Given an incoming IP datagram (as a chain of pbufs) this function

 * finds a corresponding RAW PCB and calls the corresponding receive

 * callback function.

 *

 * @param p pbuf to be demultiplexed to a RAW PCB.

 * @param inp network interface on which the datagram was received.

 * @return - 1 if the packet has been eaten by a RAW PCB receive

 *           callback function. The caller MAY NOT not reference the

 *           packet any longer, and MAY NOT call pbuf_free().

 * @return - 0 if packet is not eaten (pbuf is still referenced by the

 *           caller).

 *

 */

u8_t

raw_input(struct pbuf *p, struct netif *inp)

{

  struct raw_pcb *pcb, *prev;

  struct ip_hdr *iphdr;

  s16_t proto;

  u8_t eaten = 0;

  LWIP_UNUSED_ARG(inp);

  iphdr = p->payload;

  proto = IPH_PROTO(iphdr);

  prev = NULL;

  pcb = raw_pcbs;

  /* loop through all raw pcbs until the packet is eaten by one */

  /* this allows multiple pcbs to match against the packet by design */

  while ((eaten == 0) && (pcb != NULL)) {

    if (pcb->protocol == proto) {

      /* receive callback function available? */

      if (pcb->recv != NULL) {

        /* the receive callback function did not eat the packet? */

        if (pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src)) != 0)

        {

          /* receive function ate the packet */

          p = NULL;

          eaten = 1;

          if (prev != NULL) {

          /* move the pcb to the front of raw_pcbs so that is

             found faster next time */

            prev->next = pcb->next;

            pcb->next = raw_pcbs;

            raw_pcbs = pcb;

          }

        }

      }

      /* no receive callback function was set for this raw PCB */

      /* drop the packet */

    }

    prev = pcb;

    pcb = pcb->next;

  }

  return eaten;

}

/**

 * Bind a RAW PCB.

 *

 * @param pcb RAW PCB to be bound with a local address ipaddr.

 * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to

 * bind to all local interfaces.

 *

 * @return lwIP error code.

 * - ERR_OK. Successful. No error occured.

 * - ERR_USE. The specified IP address is already bound to by

 * another RAW PCB.

 *

 * @see raw_disconnect()

 */

err_t

raw_bind(struct raw_pcb *pcb, struct ip_addr *ipaddr)

{

  ip_addr_set(&pcb->local_ip, ipaddr);

  return ERR_OK;

}

/**

 * Connect an RAW PCB. This function is required by upper layers

 * of lwip. Using the raw api you could use raw_sendto() instead

 *

 * This will associate the RAW PCB with the remote address.

 *

 * @param pcb RAW PCB to be connected with remote address ipaddr and port.

 * @param ipaddr remote IP address to connect with.

 *

 * @return lwIP error code

 *

 * @see raw_disconnect() and raw_sendto()

 */

err_t

raw_connect(struct raw_pcb *pcb, struct ip_addr *ipaddr)

{

  ip_addr_set(&pcb->remote_ip, ipaddr);

  return ERR_OK;

}

/**

 * Set the callback function for received packets that match the

 * raw PCB's protocol and binding.

 *

 * The callback function MUST either

 * - eat the packet by calling pbuf_free() and returning non-zero. The

 *   packet will not be passed to other raw PCBs or other protocol layers.

 * - not free the packet, and return zero. The packet will be matched

 *   against further PCBs and/or forwarded to another protocol layers.

 *

 * @return non-zero if the packet was free()d, zero if the packet remains

 * available for others.

 */

void

raw_recv(struct raw_pcb *pcb,

         u8_t (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p,

                      struct ip_addr *addr),

         void *recv_arg)

{

  /* remember recv() callback and user data */

  pcb->recv = recv;

  pcb->recv_arg = recv_arg;

}

/**

 * Send the raw IP packet to the given address. Note that actually you cannot

 * modify the IP headers (this is inconsistent with the receive callback where

 * you actually get the IP headers), you can only specify the IP payload here.

 * It requires some more changes in lwIP. (there will be a raw_send() function

 * then.)

 *

 * @param pcb the raw pcb which to send

 * @param p the IP payload to send

 * @param ipaddr the destination address of the IP packet

 *

 */

err_t

raw_sendto(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)

{

  err_t err;

  struct netif *netif;

  struct ip_addr *src_ip;

  struct pbuf *q; /* q will be sent down the stack */

  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_sendto\n"));

  /* not enough space to add an IP header to first pbuf in given p chain? */

  if (pbuf_header(p, IP_HLEN)) {

    /* allocate header in new pbuf */

    q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);

    /* new header pbuf could not be allocated? */

    if (q == NULL) {

      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 2, ("raw_sendto: could not allocate header\n"));

      return ERR_MEM;

    }

    /* chain header q in front of given pbuf p */

    pbuf_chain(q, p);

    /* { first pbuf q points to header pbuf } */

    LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));

  }  else {

    /* first pbuf q equals given pbuf */

    q = p;

    if(pbuf_header(q, -IP_HLEN)) {

      LWIP_ASSERT("Can't restore header we just removed!", 0);

      return ERR_MEM;

    }

  }

  if ((netif = ip_route(ipaddr)) == NULL) {

    LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_sendto: No route to 0x%"X32_F"\n", ipaddr->addr));

    /* free any temporary header pbuf allocated by pbuf_header() */

    if (q != p) {

      pbuf_free(q);

    }

    return ERR_RTE;

  }

  if (ip_addr_isany(&pcb->local_ip)) {

    /* use outgoing network interface IP address as source address */

    src_ip = &(netif->ip_addr);

  } else {

    /* use RAW PCB local IP address as source address */

    src_ip = &(pcb->local_ip);

  }

#if LWIP_NETIF_HWADDRHINT

  netif->addr_hint = &(pcb->addr_hint);

#endif /* LWIP_NETIF_HWADDRHINT*/

  err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);

#if LWIP_NETIF_HWADDRHINT

  netif->addr_hint = NULL;

#endif /* LWIP_NETIF_HWADDRHINT*/

  /* did we chain a header earlier? */

  if (q != p) {

    /* free the header */

    pbuf_free(q);

  }

  return err;

}

/**

 * Send the raw IP packet to the address given by raw_connect()

 *

 * @param pcb the raw pcb which to send

 * @param p the IP payload to send

 *

 */

err_t

raw_send(struct raw_pcb *pcb, struct pbuf *p)

{

  return raw_sendto(pcb, p, &pcb->remote_ip);

}

/**

 * Remove an RAW PCB.

 *

 * @param pcb RAW PCB to be removed. The PCB is removed from the list of

 * RAW PCB's and the data structure is freed from memory.

 *

 * @see raw_new()

 */

void

raw_remove(struct raw_pcb *pcb)

{

  struct raw_pcb *pcb2;

  /* pcb to be removed is first in list? */

  if (raw_pcbs == pcb) {

    /* make list start at 2nd pcb */

    raw_pcbs = raw_pcbs->next;

    /* pcb not 1st in list */

  } else {

    for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {

      /* find pcb in raw_pcbs list */

      if (pcb2->next != NULL && pcb2->next == pcb) {

        /* remove pcb from list */

        pcb2->next = pcb->next;

      }

    }

  }

  memp_free(MEMP_RAW_PCB, pcb);

}

/**

 * Create a RAW PCB.

 *

 * @return The RAW PCB which was created. NULL if the PCB data structure

 * could not be allocated.

 *

 * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)

 *

 * @see raw_remove()

 */

struct raw_pcb *

raw_new(u8_t proto) {

  struct raw_pcb *pcb;

  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_new\n"));

  pcb = memp_malloc(MEMP_RAW_PCB);

  /* could allocate RAW PCB? */

  if (pcb != NULL) {

    /* initialize PCB to all zeroes */

    memset(pcb, 0, sizeof(struct raw_pcb));

    pcb->protocol = proto;

    pcb->ttl = RAW_TTL;

    pcb->next = raw_pcbs;

    raw_pcbs = pcb;

  }

  return pcb;

}

#endif /* LWIP_RAW */