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raw.c

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00001 /**
00002  * @file
00003  * Implementation of raw protocol PCBs for low-level handling of
00004  * different types of protocols besides (or overriding) those
00005  * already available in lwIP.
00006  *
00007  */
00008 
00009 /*
00010  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00011  * All rights reserved.
00012  *
00013  * Redistribution and use in source and binary forms, with or without modification,
00014  * are permitted provided that the following conditions are met:
00015  *
00016  * 1. Redistributions of source code must retain the above copyright notice,
00017  *    this list of conditions and the following disclaimer.
00018  * 2. Redistributions in binary form must reproduce the above copyright notice,
00019  *    this list of conditions and the following disclaimer in the documentation
00020  *    and/or other materials provided with the distribution.
00021  * 3. The name of the author may not be used to endorse or promote products
00022  *    derived from this software without specific prior written permission.
00023  *
00024  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00025  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00026  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00027  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00028  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00029  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00032  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00033  * OF SUCH DAMAGE.
00034  *
00035  * This file is part of the lwIP TCP/IP stack.
00036  *
00037  * Author: Adam Dunkels <adam@sics.se>
00038  *
00039  */
00040 
00041 #include "lwip/opt.h"
00042 
00043 #if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
00044 
00045 #include "lwip/def.h"
00046 #include "lwip/memp.h"
00047 #include "lwip/ip_addr.h"
00048 #include "lwip/netif.h"
00049 #include "lwip/raw.h"
00050 #include "lwip/stats.h"
00051 #include "arch/perf.h"
00052 
00053 #include <string.h>
00054 
00055 /** The list of RAW PCBs */
00056 static struct raw_pcb *raw_pcbs;
00057 
00058 /**
00059  * Determine if in incoming IP packet is covered by a RAW PCB
00060  * and if so, pass it to a user-provided receive callback function.
00061  *
00062  * Given an incoming IP datagram (as a chain of pbufs) this function
00063  * finds a corresponding RAW PCB and calls the corresponding receive
00064  * callback function.
00065  *
00066  * @param p pbuf to be demultiplexed to a RAW PCB.
00067  * @param inp network interface on which the datagram was received.
00068  * @return - 1 if the packet has been eaten by a RAW PCB receive
00069  *           callback function. The caller MAY NOT not reference the
00070  *           packet any longer, and MAY NOT call pbuf_free().
00071  * @return - 0 if packet is not eaten (pbuf is still referenced by the
00072  *           caller).
00073  *
00074  */
00075 u8_t
00076 raw_input(struct pbuf *p, struct netif *inp)
00077 {
00078   struct raw_pcb *pcb, *prev;
00079   struct ip_hdr *iphdr;
00080   s16_t proto;
00081   u8_t eaten = 0;
00082 
00083   LWIP_UNUSED_ARG(inp);
00084 
00085   iphdr = (struct ip_hdr *)p->payload;
00086   proto = IPH_PROTO(iphdr);
00087 
00088   prev = NULL;
00089   pcb = raw_pcbs;
00090   /* loop through all raw pcbs until the packet is eaten by one */
00091   /* this allows multiple pcbs to match against the packet by design */
00092   while ((eaten == 0) && (pcb != NULL)) {
00093     if ((pcb->protocol == proto) &&
00094         (ip_addr_isany(&pcb->local_ip) ||
00095          ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest))) {
00096 #if IP_SOF_BROADCAST_RECV
00097       /* broadcast filter? */
00098       if ((pcb->so_options & SOF_BROADCAST) || !ip_addr_isbroadcast(&current_iphdr_dest, inp))
00099 #endif /* IP_SOF_BROADCAST_RECV */
00100       {
00101         /* receive callback function available? */
00102         if (pcb->recv != NULL) {
00103           /* the receive callback function did not eat the packet? */
00104           if (pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr()) != 0) {
00105             /* receive function ate the packet */
00106             p = NULL;
00107             eaten = 1;
00108             if (prev != NULL) {
00109             /* move the pcb to the front of raw_pcbs so that is
00110                found faster next time */
00111               prev->next = pcb->next;
00112               pcb->next = raw_pcbs;
00113               raw_pcbs = pcb;
00114             }
00115           }
00116         }
00117         /* no receive callback function was set for this raw PCB */
00118       }
00119       /* drop the packet */
00120     }
00121     prev = pcb;
00122     pcb = pcb->next;
00123   }
00124   return eaten;
00125 }
00126 
00127 /**
00128  * Bind a RAW PCB.
00129  *
00130  * @param pcb RAW PCB to be bound with a local address ipaddr.
00131  * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
00132  * bind to all local interfaces.
00133  *
00134  * @return lwIP error code.
00135  * - ERR_OK. Successful. No error occured.
00136  * - ERR_USE. The specified IP address is already bound to by
00137  * another RAW PCB.
00138  *
00139  * @see raw_disconnect()
00140  */
00141 err_t
00142 raw_bind(struct raw_pcb *pcb, ip_addr_t *ipaddr)
00143 {
00144   ip_addr_set(&pcb->local_ip, ipaddr);
00145   return ERR_OK;
00146 }
00147 
00148 /**
00149  * Connect an RAW PCB. This function is required by upper layers
00150  * of lwip. Using the raw api you could use raw_sendto() instead
00151  *
00152  * This will associate the RAW PCB with the remote address.
00153  *
00154  * @param pcb RAW PCB to be connected with remote address ipaddr and port.
00155  * @param ipaddr remote IP address to connect with.
00156  *
00157  * @return lwIP error code
00158  *
00159  * @see raw_disconnect() and raw_sendto()
00160  */
00161 err_t
00162 raw_connect(struct raw_pcb *pcb, ip_addr_t *ipaddr)
00163 {
00164   ip_addr_set(&pcb->remote_ip, ipaddr);
00165   return ERR_OK;
00166 }
00167 
00168 
00169 /**
00170  * Set the callback function for received packets that match the
00171  * raw PCB's protocol and binding. 
00172  * 
00173  * The callback function MUST either
00174  * - eat the packet by calling pbuf_free() and returning non-zero. The
00175  *   packet will not be passed to other raw PCBs or other protocol layers.
00176  * - not free the packet, and return zero. The packet will be matched
00177  *   against further PCBs and/or forwarded to another protocol layers.
00178  * 
00179  * @return non-zero if the packet was free()d, zero if the packet remains
00180  * available for others.
00181  */
00182 void
00183 raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
00184 {
00185   /* remember recv() callback and user data */
00186   pcb->recv = recv;
00187   pcb->recv_arg = recv_arg;
00188 }
00189 
00190 /**
00191  * Send the raw IP packet to the given address. Note that actually you cannot
00192  * modify the IP headers (this is inconsistent with the receive callback where
00193  * you actually get the IP headers), you can only specify the IP payload here.
00194  * It requires some more changes in lwIP. (there will be a raw_send() function
00195  * then.)
00196  *
00197  * @param pcb the raw pcb which to send
00198  * @param p the IP payload to send
00199  * @param ipaddr the destination address of the IP packet
00200  *
00201  */
00202 err_t
00203 raw_sendto(struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *ipaddr)
00204 {
00205   err_t err;
00206   struct netif *netif;
00207   ip_addr_t *src_ip;
00208   struct pbuf *q; /* q will be sent down the stack */
00209   
00210   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
00211   
00212   /* not enough space to add an IP header to first pbuf in given p chain? */
00213   if (pbuf_header(p, IP_HLEN)) {
00214     /* allocate header in new pbuf */
00215     q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
00216     /* new header pbuf could not be allocated? */
00217     if (q == NULL) {
00218       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
00219       return ERR_MEM;
00220     }
00221     if (p->tot_len != 0) {
00222       /* chain header q in front of given pbuf p */
00223       pbuf_chain(q, p);
00224     }
00225     /* { first pbuf q points to header pbuf } */
00226     LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
00227   }  else {
00228     /* first pbuf q equals given pbuf */
00229     q = p;
00230     if(pbuf_header(q, -IP_HLEN)) {
00231       LWIP_ASSERT("Can't restore header we just removed!", 0);
00232       return ERR_MEM;
00233     }
00234   }
00235 
00236   if ((netif = ip_route(ipaddr)) == NULL) {
00237     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00238       ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
00239     /* free any temporary header pbuf allocated by pbuf_header() */
00240     if (q != p) {
00241       pbuf_free(q);
00242     }
00243     return ERR_RTE;
00244   }
00245 
00246 #if IP_SOF_BROADCAST
00247   /* broadcast filter? */
00248   if (((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(ipaddr, netif)) {
00249     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
00250     /* free any temporary header pbuf allocated by pbuf_header() */
00251     if (q != p) {
00252       pbuf_free(q);
00253     }
00254     return ERR_VAL;
00255   }
00256 #endif /* IP_SOF_BROADCAST */
00257 
00258   if (ip_addr_isany(&pcb->local_ip)) {
00259     /* use outgoing network interface IP address as source address */
00260     src_ip = &(netif->ip_addr);
00261   } else {
00262     /* use RAW PCB local IP address as source address */
00263     src_ip = &(pcb->local_ip);
00264   }
00265 
00266 #if LWIP_NETIF_HWADDRHINT
00267   netif->addr_hint = &(pcb->addr_hint);
00268 #endif /* LWIP_NETIF_HWADDRHINT*/
00269   err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
00270 #if LWIP_NETIF_HWADDRHINT
00271   netif->addr_hint = NULL;
00272 #endif /* LWIP_NETIF_HWADDRHINT*/
00273 
00274   /* did we chain a header earlier? */
00275   if (q != p) {
00276     /* free the header */
00277     pbuf_free(q);
00278   }
00279   return err;
00280 }
00281 
00282 /**
00283  * Send the raw IP packet to the address given by raw_connect()
00284  *
00285  * @param pcb the raw pcb which to send
00286  * @param p the IP payload to send
00287  *
00288  */
00289 err_t
00290 raw_send(struct raw_pcb *pcb, struct pbuf *p)
00291 {
00292   return raw_sendto(pcb, p, &pcb->remote_ip);
00293 }
00294 
00295 /**
00296  * Remove an RAW PCB.
00297  *
00298  * @param pcb RAW PCB to be removed. The PCB is removed from the list of
00299  * RAW PCB's and the data structure is freed from memory.
00300  *
00301  * @see raw_new()
00302  */
00303 void
00304 raw_remove(struct raw_pcb *pcb)
00305 {
00306   struct raw_pcb *pcb2;
00307   /* pcb to be removed is first in list? */
00308   if (raw_pcbs == pcb) {
00309     /* make list start at 2nd pcb */
00310     raw_pcbs = raw_pcbs->next;
00311     /* pcb not 1st in list */
00312   } else {
00313     for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
00314       /* find pcb in raw_pcbs list */
00315       if (pcb2->next != NULL && pcb2->next == pcb) {
00316         /* remove pcb from list */
00317         pcb2->next = pcb->next;
00318       }
00319     }
00320   }
00321   memp_free(MEMP_RAW_PCB, pcb);
00322 }
00323 
00324 /**
00325  * Create a RAW PCB.
00326  *
00327  * @return The RAW PCB which was created. NULL if the PCB data structure
00328  * could not be allocated.
00329  *
00330  * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
00331  *
00332  * @see raw_remove()
00333  */
00334 struct raw_pcb *
00335 raw_new(u8_t proto)
00336 {
00337   struct raw_pcb *pcb;
00338 
00339   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
00340 
00341   pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
00342   /* could allocate RAW PCB? */
00343   if (pcb != NULL) {
00344     /* initialize PCB to all zeroes */
00345     memset(pcb, 0, sizeof(struct raw_pcb));
00346     pcb->protocol = proto;
00347     pcb->ttl = RAW_TTL;
00348     pcb->next = raw_pcbs;
00349     raw_pcbs = pcb;
00350   }
00351   return pcb;
00352 }
00353 
00354 #endif /* LWIP_RAW */