raw.c

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/inet.h"
00048 #include "lwip/ip_addr.h"
00049 #include "lwip/netif.h"
00050 #include "lwip/raw.h"
00051 #include "lwip/stats.h"
00052 #include "lwip/snmp.h"
00053 #include "arch/perf.h"
00054 
00055 #include <string.h>
00056 
00057 /** The list of RAW PCBs */
00058 static struct raw_pcb *raw_pcbs;
00059 
00060 /**
00061  * Determine if in incoming IP packet is covered by a RAW PCB
00062  * and if so, pass it to a user-provided receive callback function.
00063  *
00064  * Given an incoming IP datagram (as a chain of pbufs) this function
00065  * finds a corresponding RAW PCB and calls the corresponding receive
00066  * callback function.
00067  *
00068  * @param p pbuf to be demultiplexed to a RAW PCB.
00069  * @param inp network interface on which the datagram was received.
00070  * @return - 1 if the packet has been eaten by a RAW PCB receive
00071  *           callback function. The caller MAY NOT not reference the
00072  *           packet any longer, and MAY NOT call pbuf_free().
00073  * @return - 0 if packet is not eaten (pbuf is still referenced by the
00074  *           caller).
00075  *
00076  */
00077 u8_t
00078 raw_input(struct pbuf *p, struct netif *inp)
00079 {
00080   struct raw_pcb *pcb, *prev;
00081   struct ip_hdr *iphdr;
00082   s16_t proto;
00083   u8_t eaten = 0;
00084 
00085   LWIP_UNUSED_ARG(inp);
00086 
00087   iphdr = static_cast<struct ip_hdr *>(p->payload);
00088   proto = IPH_PROTO(iphdr);
00089 
00090   prev = NULL;
00091   pcb = raw_pcbs;
00092   /* loop through all raw pcbs until the packet is eaten by one */
00093   /* this allows multiple pcbs to match against the packet by design */
00094   while ((eaten == 0) && (pcb != NULL)) {
00095     if (pcb->protocol == proto) {
00096       /* receive callback function available? */
00097       if (pcb->recv != NULL) {
00098         /* the receive callback function did not eat the packet? */
00099         struct ip_addr iphdrsrc;
00100         iphdrsrc.addr = iphdr->src.addr;
00101         if (pcb->recv(pcb->recv_arg, pcb, p, &(iphdrsrc)) != 0)
00102         {
00103           /* receive function ate the packet */
00104           p = NULL;
00105           eaten = 1;
00106           if (prev != NULL) {
00107           /* move the pcb to the front of raw_pcbs so that is
00108              found faster next time */
00109             prev->next = pcb->next;
00110             pcb->next = raw_pcbs;
00111             raw_pcbs = pcb;
00112           }
00113         }
00114       }
00115       /* no receive callback function was set for this raw PCB */
00116       /* drop the packet */
00117     }
00118     prev = pcb;
00119     pcb = pcb->next;
00120   }
00121   return eaten;
00122 }
00123 
00124 /**
00125  * Bind a RAW PCB.
00126  *
00127  * @param pcb RAW PCB to be bound with a local address ipaddr.
00128  * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
00129  * bind to all local interfaces.
00130  *
00131  * @return lwIP error code.
00132  * - ERR_OK. Successful. No error occured.
00133  * - ERR_USE. The specified IP address is already bound to by
00134  * another RAW PCB.
00135  *
00136  * @see raw_disconnect()
00137  */
00138 err_t
00139 raw_bind(struct raw_pcb *pcb, struct ip_addr *ipaddr)
00140 {
00141   ip_addr_set(&pcb->local_ip, ipaddr);
00142   return ERR_OK;
00143 }
00144 
00145 /**
00146  * Connect an RAW PCB. This function is required by upper layers
00147  * of lwip. Using the raw api you could use raw_sendto() instead
00148  *
00149  * This will associate the RAW PCB with the remote address.
00150  *
00151  * @param pcb RAW PCB to be connected with remote address ipaddr and port.
00152  * @param ipaddr remote IP address to connect with.
00153  *
00154  * @return lwIP error code
00155  *
00156  * @see raw_disconnect() and raw_sendto()
00157  */
00158 err_t
00159 raw_connect(struct raw_pcb *pcb, struct ip_addr *ipaddr)
00160 {
00161   ip_addr_set(&pcb->remote_ip, ipaddr);
00162   return ERR_OK;
00163 }
00164 
00165 
00166 /**
00167  * Set the callback function for received packets that match the
00168  * raw PCB's protocol and binding. 
00169  * 
00170  * The callback function MUST either
00171  * - eat the packet by calling pbuf_free() and returning non-zero. The
00172  *   packet will not be passed to other raw PCBs or other protocol layers.
00173  * - not free the packet, and return zero. The packet will be matched
00174  *   against further PCBs and/or forwarded to another protocol layers.
00175  * 
00176  * @return non-zero if the packet was free()d, zero if the packet remains
00177  * available for others.
00178  */
00179 void
00180 raw_recv(struct raw_pcb *pcb,
00181          u8_t (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p,
00182                       struct ip_addr *addr),
00183          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, struct ip_addr *ipaddr)
00204 {
00205   err_t err;
00206   struct netif *netif;
00207   struct ip_addr *src_ip;
00208   struct pbuf *q; /* q will be sent down the stack */
00209   
00210   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("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 | 2, ("raw_sendto: could not allocate header\n"));
00219       return ERR_MEM;
00220     }
00221     /* chain header q in front of given pbuf p */
00222     pbuf_chain(q, p);
00223     /* { first pbuf q points to header pbuf } */
00224     LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
00225   }  else {
00226     /* first pbuf q equals given pbuf */
00227     q = p;
00228     if(pbuf_header(q, -IP_HLEN)) {
00229       LWIP_ASSERT("Can't restore header we just removed!", 0);
00230       return ERR_MEM;
00231     }
00232   }
00233   
00234   if ((netif = ip_route(ipaddr)) == NULL) {
00235     LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_sendto: No route to 0x%"X32_F"\n", ipaddr->addr));
00236     /* free any temporary header pbuf allocated by pbuf_header() */
00237     if (q != p) {
00238       pbuf_free(q);
00239     }
00240     return ERR_RTE;
00241   }
00242 
00243   if (ip_addr_isany(&pcb->local_ip)) {
00244     /* use outgoing network interface IP address as source address */
00245     src_ip = &(netif->ip_addr);
00246   } else {
00247     /* use RAW PCB local IP address as source address */
00248     src_ip = &(pcb->local_ip);
00249   }
00250 
00251 #if LWIP_NETIF_HWADDRHINT
00252   netif->addr_hint = &(pcb->addr_hint);
00253 #endif /* LWIP_NETIF_HWADDRHINT*/
00254   err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
00255 #if LWIP_NETIF_HWADDRHINT
00256   netif->addr_hint = NULL;
00257 #endif /* LWIP_NETIF_HWADDRHINT*/
00258 
00259   /* did we chain a header earlier? */
00260   if (q != p) {
00261     /* free the header */
00262     pbuf_free(q);
00263   }
00264   return err;
00265 }
00266 
00267 /**
00268  * Send the raw IP packet to the address given by raw_connect()
00269  *
00270  * @param pcb the raw pcb which to send
00271  * @param p the IP payload to send
00272  *
00273  */
00274 err_t
00275 raw_send(struct raw_pcb *pcb, struct pbuf *p)
00276 {
00277   return raw_sendto(pcb, p, &pcb->remote_ip);
00278 }
00279 
00280 /**
00281  * Remove an RAW PCB.
00282  *
00283  * @param pcb RAW PCB to be removed. The PCB is removed from the list of
00284  * RAW PCB's and the data structure is freed from memory.
00285  *
00286  * @see raw_new()
00287  */
00288 void
00289 raw_remove(struct raw_pcb *pcb)
00290 {
00291   struct raw_pcb *pcb2;
00292   /* pcb to be removed is first in list? */
00293   if (raw_pcbs == pcb) {
00294     /* make list start at 2nd pcb */
00295     raw_pcbs = raw_pcbs->next;
00296     /* pcb not 1st in list */
00297   } else {
00298     for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
00299       /* find pcb in raw_pcbs list */
00300       if (pcb2->next != NULL && pcb2->next == pcb) {
00301         /* remove pcb from list */
00302         pcb2->next = pcb->next;
00303       }
00304     }
00305   }
00306   memp_free(MEMP_RAW_PCB, pcb);
00307 }
00308 
00309 /**
00310  * Create a RAW PCB.
00311  *
00312  * @return The RAW PCB which was created. NULL if the PCB data structure
00313  * could not be allocated.
00314  *
00315  * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
00316  *
00317  * @see raw_remove()
00318  */
00319 struct raw_pcb *
00320 raw_new(u8_t proto) {
00321   struct raw_pcb *pcb;
00322 
00323   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | 3, ("raw_new\n"));
00324 
00325   pcb = static_cast<struct raw_pcb *>(memp_malloc(MEMP_RAW_PCB));
00326   /* could allocate RAW PCB? */
00327   if (pcb != NULL) {
00328     /* initialize PCB to all zeroes */
00329     memset(pcb, 0, sizeof(struct raw_pcb));
00330     pcb->protocol = proto;
00331     pcb->ttl = RAW_TTL;
00332     pcb->next = raw_pcbs;
00333     raw_pcbs = pcb;
00334   }
00335   return pcb;
00336 }
00337 
00338 #endif /* LWIP_RAW */