lib/liblwip/core/raw.c

   1 /**
   2  * @file
   3  * Implementation of raw protocol PCBs for low-level handling of
   4  * different types of protocols besides (or overriding) those
   5  * already available in lwIP.
   6  *
   7  */
   8
   9 /*
  10  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
  11  * All rights reserved.
  12  *
  13  * Redistribution and use in source and binary forms, with or without modification,
  14  * are permitted provided that the following conditions are met:
  15  *
  16  * 1. Redistributions of source code must retain the above copyright notice,
  17  *    this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright notice,
  19  *    this list of conditions and the following disclaimer in the documentation
  20  *    and/or other materials provided with the distribution.
  21  * 3. The name of the author may not be used to endorse or promote products
  22  *    derived from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  25  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  26  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  27  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  28  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  29  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  32  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  33  * OF SUCH DAMAGE.
  34  *
  35  * This file is part of the lwIP TCP/IP stack.
  36  *
  37  * Author: Adam Dunkels <adam@sics.se>
  38  *
  39  */
  40
  41 #include "lwip/opt.h"
  42
  43 #if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
  44
  45 #include "lwip/def.h"
  46 #include "lwip/memp.h"
  47 #include "lwip/ip_addr.h"
  48 #include "lwip/netif.h"
  49 #include "lwip/raw.h"
  50 #include "lwip/stats.h"
  51 #include "arch/perf.h"
  52
  53 #include <string.h>
  54
  55 /** The list of RAW PCBs */
  56 static struct raw_pcb *raw_pcbs;
  57
  58 /**
  59  * Determine if in incoming IP packet is covered by a RAW PCB
  60  * and if so, pass it to a user-provided receive callback function.
  61  *
  62  * Given an incoming IP datagram (as a chain of pbufs) this function
  63  * finds a corresponding RAW PCB and calls the corresponding receive
  64  * callback function.
  65  *
  66  * @param p pbuf to be demultiplexed to a RAW PCB.
  67  * @param inp network interface on which the datagram was received.
  68  * @return - 1 if the packet has been eaten by a RAW PCB receive
  69  *           callback function. The caller MAY NOT not reference the
  70  *           packet any longer, and MAY NOT call pbuf_free().
  71  * @return - 0 if packet is not eaten (pbuf is still referenced by the
  72  *           caller).
  73  *
  74  */
  75 u8_t
  76 raw_input(struct pbuf *p, struct netif *inp)
  77 {
  78   struct raw_pcb *pcb, *prev;
  79   struct ip_hdr *iphdr;
  80   s16_t proto;
  81   u8_t eaten = 0;
  82
  83   LWIP_UNUSED_ARG(inp);
  84
  85   iphdr = (struct ip_hdr *)p->payload;
  86   proto = IPH_PROTO(iphdr);
  87
  88   prev = NULL;
  89   pcb = raw_pcbs;
  90   /* loop through all raw pcbs until the packet is eaten by one */
  91   /* this allows multiple pcbs to match against the packet by design */
  92   while ((eaten == 0) && (pcb != NULL)) {
  93     if ((pcb->protocol == IP_PROTO_ANY || pcb->protocol == proto) &&
  94         (ip_addr_isany(&pcb->local_ip) ||
  95          ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest))) {
  96 #if IP_SOF_BROADCAST_RECV
  97       /* broadcast filter? */
  98       if ((pcb->so_options & SOF_BROADCAST) || !ip_addr_isbroadcast(&current_iphdr_dest, inp))
  99 #endif /* IP_SOF_BROADCAST_RECV */
 100       {
 101         /* receive callback function available? */
 102         if (pcb->recv != NULL) {
 103           /* the receive callback function did not eat the packet? */
 104           if (pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr()) != 0) {
 105             /* receive function ate the packet */
 106             p = NULL;
 107             eaten = 1;
 108             if (prev != NULL) {
 109             /* move the pcb to the front of raw_pcbs so that is
 110                found faster next time */
 111               prev->next = pcb->next;
 112               pcb->next = raw_pcbs;
 113               raw_pcbs = pcb;
 114             }
 115           }
 116         }
 117         /* no receive callback function was set for this raw PCB */
 118       }
 119       /* drop the packet */
 120     }
 121     prev = pcb;
 122     pcb = pcb->next;
 123   }
 124   return eaten;
 125 }
 126
 127 /**
 128  * Bind a RAW PCB.
 129  *
 130  * @param pcb RAW PCB to be bound with a local address ipaddr.
 131  * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
 132  * bind to all local interfaces.
 133  *
 134  * @return lwIP error code.
 135  * - ERR_OK. Successful. No error occured.
 136  * - ERR_USE. The specified IP address is already bound to by
 137  * another RAW PCB.
 138  *
 139  * @see raw_disconnect()
 140  */
 141 err_t
 142 raw_bind(struct raw_pcb *pcb, ip_addr_t *ipaddr)
 143 {
 144   ip_addr_set(&pcb->local_ip, ipaddr);
 145   return ERR_OK;
 146 }
 147
 148 /**
 149  * Connect an RAW PCB. This function is required by upper layers
 150  * of lwip. Using the raw api you could use raw_sendto() instead
 151  *
 152  * This will associate the RAW PCB with the remote address.
 153  *
 154  * @param pcb RAW PCB to be connected with remote address ipaddr and port.
 155  * @param ipaddr remote IP address to connect with.
 156  *
 157  * @return lwIP error code
 158  *
 159  * @see raw_disconnect() and raw_sendto()
 160  */
 161 err_t
 162 raw_connect(struct raw_pcb *pcb, ip_addr_t *ipaddr)
 163 {
 164   ip_addr_set(&pcb->remote_ip, ipaddr);
 165   return ERR_OK;
 166 }
 167
 168
 169 /**
 170  * Set the callback function for received packets that match the
 171  * raw PCB's protocol and binding.
 172  *
 173  * The callback function MUST either
 174  * - eat the packet by calling pbuf_free() and returning non-zero. The
 175  *   packet will not be passed to other raw PCBs or other protocol layers.
 176  * - not free the packet, and return zero. The packet will be matched
 177  *   against further PCBs and/or forwarded to another protocol layers.
 178  *
 179  * @return non-zero if the packet was free()d, zero if the packet remains
 180  * available for others.
 181  */
 182 void
 183 raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
 184 {
 185   /* remember recv() callback and user data */
 186   pcb->recv = recv;
 187   pcb->recv_arg = recv_arg;
 188 }
 189
 190 /**
 191  * Send the raw IP packet to the given address. Note that actually you cannot
 192  * modify the IP headers (this is inconsistent with the receive callback where
 193  * you actually get the IP headers), you can only specify the IP payload here.
 194  * It requires some more changes in lwIP. (there will be a raw_send() function
 195  * then.)
 196  *
 197  * @param pcb the raw pcb which to send
 198  * @param p the IP payload to send
 199  * @param ipaddr the destination address of the IP packet
 200  *
 201  */
 202 err_t
 203 raw_sendto(struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *ipaddr)
 204 {
 205   err_t err;
 206   struct netif *netif;
 207   ip_addr_t *src_ip;
 208   struct pbuf *q; /* q will be sent down the stack */
 209
 210   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
 211
 212   /* not enough space to add an IP header to first pbuf in given p chain? */
 213   if (pbuf_header(p, IP_HLEN)) {
 214     /* allocate header in new pbuf */
 215     q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
 216     /* new header pbuf could not be allocated? */
 217     if (q == NULL) {
 218       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
 219       return ERR_MEM;
 220     }
 221     /* chain header q in front of given pbuf p */
 222     pbuf_chain(q, p);
 223     /* { first pbuf q points to header pbuf } */
 224     LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
 225   }  else {
 226     /* first pbuf q equals given pbuf */
 227     q = p;
 228     if(pbuf_header(q, -IP_HLEN)) {
 229       LWIP_ASSERT("Can't restore header we just removed!", 0);
 230       return ERR_MEM;
 231     }
 232   }
 233
 234   if ((netif = ip_route(ipaddr)) == NULL) {
 235     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
 236       ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
 237     /* free any temporary header pbuf allocated by pbuf_header() */
 238     if (q != p) {
 239       pbuf_free(q);
 240     }
 241     return ERR_RTE;
 242   }
 243
 244 #if IP_SOF_BROADCAST
 245   /* broadcast filter? */
 246   if (((pcb->so_options & SOF_BROADCAST) == 0) && ip_addr_isbroadcast(ipaddr, netif)) {
 247     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
 248     /* free any temporary header pbuf allocated by pbuf_header() */
 249     if (q != p) {
 250       pbuf_free(q);
 251     }
 252     return ERR_VAL;
 253   }
 254 #endif /* IP_SOF_BROADCAST */
 255
 256   if (ip_addr_isany(&pcb->local_ip)) {
 257     /* use outgoing network interface IP address as source address */
 258     src_ip = &(netif->ip_addr);
 259   } else {
 260     /* use RAW PCB local IP address as source address */
 261     src_ip = &(pcb->local_ip);
 262   }
 263
 264 #if LWIP_NETIF_HWADDRHINT
 265   netif->addr_hint = &(pcb->addr_hint);
 266 #endif /* LWIP_NETIF_HWADDRHINT*/
 267   err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
 268 #if LWIP_NETIF_HWADDRHINT
 269   netif->addr_hint = NULL;
 270 #endif /* LWIP_NETIF_HWADDRHINT*/
 271
 272   /* did we chain a header earlier? */
 273   if (q != p) {
 274     /* free the header */
 275     pbuf_free(q);
 276   }
 277   return err;
 278 }
 279
 280 /**
 281  * Send the raw IP packet to the address given by raw_connect()
 282  *
 283  * @param pcb the raw pcb which to send
 284  * @param p the IP payload to send
 285  *
 286  */
 287 err_t
 288 raw_send(struct raw_pcb *pcb, struct pbuf *p)
 289 {
 290   return raw_sendto(pcb, p, &pcb->remote_ip);
 291 }
 292
 293 /**
 294  * Remove an RAW PCB.
 295  *
 296  * @param pcb RAW PCB to be removed. The PCB is removed from the list of
 297  * RAW PCB's and the data structure is freed from memory.
 298  *
 299  * @see raw_new()
 300  */
 301 void
 302 raw_remove(struct raw_pcb *pcb)
 303 {
 304   struct raw_pcb *pcb2;
 305   /* pcb to be removed is first in list? */
 306   if (raw_pcbs == pcb) {
 307     /* make list start at 2nd pcb */
 308     raw_pcbs = raw_pcbs->next;
 309     /* pcb not 1st in list */
 310   } else {
 311     for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
 312       /* find pcb in raw_pcbs list */
 313       if (pcb2->next != NULL && pcb2->next == pcb) {
 314         /* remove pcb from list */
 315         pcb2->next = pcb->next;
 316       }
 317     }
 318   }
 319   memp_free(MEMP_RAW_PCB, pcb);
 320 }
 321
 322 /**
 323  * Create a RAW PCB.
 324  *
 325  * @return The RAW PCB which was created. NULL if the PCB data structure
 326  * could not be allocated.
 327  *
 328  * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
 329  *
 330  * @see raw_remove()
 331  */
 332 struct raw_pcb *
 333 raw_new(u8_t proto)
 334 {
 335   struct raw_pcb *pcb;
 336
 337   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
 338
 339   pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
 340   /* could allocate RAW PCB? */
 341   if (pcb != NULL) {
 342     /* initialize PCB to all zeroes */
 343     memset(pcb, 0, sizeof(struct raw_pcb));
 344     pcb->protocol = proto;
 345     pcb->ttl = RAW_TTL;
 346     pcb->next = raw_pcbs;
 347     raw_pcbs = pcb;
 348   }
 349   return pcb;
 350 }
 351
 352 #endif /* LWIP_RAW */