lwip_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.\n
00006  * See also @ref raw_raw
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 /**
00042  * @defgroup raw_api RAW API
00043  * @ingroup callbackstyle_api
00044  * @verbinclude "rawapi.txt"
00045  */
00046 
00047 /**
00048  * @defgroup raw_raw RAW
00049  * @ingroup raw_api
00050  * Implementation of raw protocol PCBs for low-level handling of
00051  * different types of protocols besides (or overriding) those
00052  * already available in lwIP.\n
00053  * @see @ref raw_api
00054  */
00055 
00056 #include "lwip/opt.h"
00057 
00058 #if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
00059 
00060 #include "lwip/def.h"
00061 #include "lwip/memp.h"
00062 #include "lwip/ip_addr.h"
00063 #include "lwip/netif.h"
00064 #include "lwip/raw.h"
00065 #include "lwip/stats.h"
00066 #include "lwip/ip6.h"
00067 #include "lwip/ip6_addr.h"
00068 #include "lwip/inet_chksum.h"
00069 
00070 #include <string.h>
00071 
00072 /** The list of RAW PCBs */
00073 static struct raw_pcb *raw_pcbs;
00074 
00075 static u8_t
00076 raw_input_match(struct raw_pcb *pcb, u8_t broadcast)
00077 {
00078   LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */
00079 
00080 #if LWIP_IPV4 && LWIP_IPV6
00081   /* Dual-stack: PCBs listening to any IP type also listen to any IP address */
00082   if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
00083 #if IP_SOF_BROADCAST_RECV
00084     if ((broadcast != 0) && !ip_get_option(pcb, SOF_BROADCAST)) {
00085       return 0;
00086     }
00087 #endif /* IP_SOF_BROADCAST_RECV */
00088     return 1;
00089   }
00090 #endif /* LWIP_IPV4 && LWIP_IPV6 */
00091   
00092   /* Only need to check PCB if incoming IP version matches PCB IP version */
00093   if (IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ip_current_dest_addr())) {
00094 #if LWIP_IPV4
00095     /* Special case: IPv4 broadcast: receive all broadcasts
00096      * Note: broadcast variable can only be 1 if it is an IPv4 broadcast */
00097     if (broadcast != 0) {
00098 #if IP_SOF_BROADCAST_RECV
00099       if (ip_get_option(pcb, SOF_BROADCAST))
00100 #endif /* IP_SOF_BROADCAST_RECV */
00101       {
00102         if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip))) {
00103           return 1;
00104         }
00105       }
00106     } else
00107 #endif /* LWIP_IPV4 */
00108     /* Handle IPv4 and IPv6: catch all or exact match */
00109     if (ip_addr_isany(&pcb->local_ip) ||
00110        ip_addr_cmp(&pcb->local_ip, ip_current_dest_addr())) {
00111       return 1;
00112     }
00113   }
00114   
00115   return 0;
00116 }
00117 
00118 /**
00119  * Determine if in incoming IP packet is covered by a RAW PCB
00120  * and if so, pass it to a user-provided receive callback function.
00121  *
00122  * Given an incoming IP datagram (as a chain of pbufs) this function
00123  * finds a corresponding RAW PCB and calls the corresponding receive
00124  * callback function.
00125  *
00126  * @param p pbuf to be demultiplexed to a RAW PCB.
00127  * @param inp network interface on which the datagram was received.
00128  * @return - 1 if the packet has been eaten by a RAW PCB receive
00129  *           callback function. The caller MAY NOT not reference the
00130  *           packet any longer, and MAY NOT call pbuf_free().
00131  * @return - 0 if packet is not eaten (pbuf is still referenced by the
00132  *           caller).
00133  *
00134  */
00135 u8_t
00136 raw_input(struct pbuf *p, struct netif *inp)
00137 {
00138   struct raw_pcb *pcb, *prev;
00139   s16_t proto;
00140   u8_t eaten = 0;
00141   u8_t broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif());
00142 
00143   LWIP_UNUSED_ARG(inp);
00144 
00145 #if LWIP_IPV6
00146 #if LWIP_IPV4
00147   if (IP_HDR_GET_VERSION(p->payload) == 6)
00148 #endif /* LWIP_IPV4 */
00149   {
00150     struct ip6_hdr *ip6hdr = (struct ip6_hdr *)p->payload;
00151     proto = IP6H_NEXTH(ip6hdr);
00152   }
00153 #if LWIP_IPV4
00154   else
00155 #endif /* LWIP_IPV4 */
00156 #endif /* LWIP_IPV6 */
00157 #if LWIP_IPV4
00158   {
00159     proto = IPH_PROTO((struct ip_hdr *)p->payload);
00160   }
00161 #endif /* LWIP_IPV4 */
00162 
00163   prev = NULL;
00164   pcb = raw_pcbs;
00165   /* loop through all raw pcbs until the packet is eaten by one */
00166   /* this allows multiple pcbs to match against the packet by design */
00167   while ((eaten == 0) && (pcb != NULL)) {
00168     if ((pcb->protocol == proto) && raw_input_match(pcb, broadcast)) {
00169       /* receive callback function available? */
00170       if (pcb->recv != NULL) {
00171 #ifndef LWIP_NOASSERT
00172         void* old_payload = p->payload;
00173 #endif
00174         /* the receive callback function did not eat the packet? */
00175         eaten = pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr());
00176         if (eaten != 0) {
00177           /* receive function ate the packet */
00178           p = NULL;
00179           eaten = 1;
00180           if (prev != NULL) {
00181           /* move the pcb to the front of raw_pcbs so that is
00182              found faster next time */
00183             prev->next = pcb->next;
00184             pcb->next = raw_pcbs;
00185             raw_pcbs = pcb;
00186           }
00187         } else {
00188           /* sanity-check that the receive callback did not alter the pbuf */
00189           LWIP_ASSERT("raw pcb recv callback altered pbuf payload pointer without eating packet",
00190             p->payload == old_payload);
00191         }
00192       }
00193       /* no receive callback function was set for this raw PCB */
00194     }
00195     /* drop the packet */
00196     prev = pcb;
00197     pcb = pcb->next;
00198   }
00199   return eaten;
00200 }
00201 
00202 /**
00203  * @ingroup raw_raw
00204  * Bind a RAW PCB.
00205  *
00206  * @param pcb RAW PCB to be bound with a local address ipaddr.
00207  * @param ipaddr local IP address to bind with. Use IP_ADDR_ANY to
00208  * bind to all local interfaces.
00209  *
00210  * @return lwIP error code.
00211  * - ERR_OK. Successful. No error occurred.
00212  * - ERR_USE. The specified IP address is already bound to by
00213  * another RAW PCB.
00214  *
00215  * @see raw_disconnect()
00216  */
00217 err_t
00218 raw_bind(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
00219 {
00220   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ipaddr)) {
00221     return ERR_VAL;
00222   }
00223   ip_addr_set_ipaddr(&pcb->local_ip, ipaddr);
00224   return ERR_OK;
00225 }
00226 
00227 /**
00228  * @ingroup raw_raw
00229  * Connect an RAW PCB. This function is required by upper layers
00230  * of lwip. Using the raw api you could use raw_sendto() instead
00231  *
00232  * This will associate the RAW PCB with the remote address.
00233  *
00234  * @param pcb RAW PCB to be connected with remote address ipaddr and port.
00235  * @param ipaddr remote IP address to connect with.
00236  *
00237  * @return lwIP error code
00238  *
00239  * @see raw_disconnect() and raw_sendto()
00240  */
00241 err_t
00242 raw_connect(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
00243 {
00244   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ipaddr)) {
00245     return ERR_VAL;
00246   }
00247   ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr);
00248   return ERR_OK;
00249 }
00250 
00251 /**
00252  * @ingroup raw_raw
00253  * Set the callback function for received packets that match the
00254  * raw PCB's protocol and binding.
00255  *
00256  * The callback function MUST either
00257  * - eat the packet by calling pbuf_free() and returning non-zero. The
00258  *   packet will not be passed to other raw PCBs or other protocol layers.
00259  * - not free the packet, and return zero. The packet will be matched
00260  *   against further PCBs and/or forwarded to another protocol layers.
00261  *
00262  * @return non-zero if the packet was free()d, zero if the packet remains
00263  * available for others.
00264  */
00265 void
00266 raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
00267 {
00268   /* remember recv() callback and user data */
00269   pcb->recv = recv;
00270   pcb->recv_arg = recv_arg;
00271 }
00272 
00273 /**
00274  * @ingroup raw_raw
00275  * Send the raw IP packet to the given address. Note that actually you cannot
00276  * modify the IP headers (this is inconsistent with the receive callback where
00277  * you actually get the IP headers), you can only specify the IP payload here.
00278  * It requires some more changes in lwIP. (there will be a raw_send() function
00279  * then.)
00280  *
00281  * @param pcb the raw pcb which to send
00282  * @param p the IP payload to send
00283  * @param ipaddr the destination address of the IP packet
00284  *
00285  */
00286 err_t
00287 raw_sendto(struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *ipaddr)
00288 {
00289   err_t err;
00290   struct netif *netif;
00291   const ip_addr_t *src_ip;
00292   struct pbuf *q; /* q will be sent down the stack */
00293   s16_t header_size;
00294   const ip_addr_t *dst_ip = ipaddr;
00295 
00296   if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) {
00297     return ERR_VAL;
00298   }
00299 
00300   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
00301 
00302   header_size = (
00303 #if LWIP_IPV4 && LWIP_IPV6
00304     IP_IS_V6(ipaddr) ? IP6_HLEN : IP_HLEN);
00305 #elif LWIP_IPV4
00306     IP_HLEN);
00307 #else
00308     IP6_HLEN);
00309 #endif
00310 
00311   /* not enough space to add an IP header to first pbuf in given p chain? */
00312   if (pbuf_header(p, header_size)) {
00313     /* allocate header in new pbuf */
00314     q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
00315     /* new header pbuf could not be allocated? */
00316     if (q == NULL) {
00317       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
00318       return ERR_MEM;
00319     }
00320     if (p->tot_len != 0) {
00321       /* chain header q in front of given pbuf p */
00322       pbuf_chain(q, p);
00323     }
00324     /* { first pbuf q points to header pbuf } */
00325     LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
00326   } else {
00327     /* first pbuf q equals given pbuf */
00328     q = p;
00329     if (pbuf_header(q, -header_size)) {
00330       LWIP_ASSERT("Can't restore header we just removed!", 0);
00331       return ERR_MEM;
00332     }
00333   }
00334 
00335   netif = ip_route(&pcb->local_ip, dst_ip);
00336   if (netif == NULL) {
00337     LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to "));
00338     ip_addr_debug_print(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, dst_ip);
00339     /* free any temporary header pbuf allocated by pbuf_header() */
00340     if (q != p) {
00341       pbuf_free(q);
00342     }
00343     return ERR_RTE;
00344   }
00345 
00346 #if IP_SOF_BROADCAST
00347   if (IP_IS_V4(ipaddr))
00348   {
00349     /* broadcast filter? */
00350     if (!ip_get_option(pcb, SOF_BROADCAST) && ip_addr_isbroadcast(ipaddr, netif)) {
00351       LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
00352       /* free any temporary header pbuf allocated by pbuf_header() */
00353       if (q != p) {
00354         pbuf_free(q);
00355       }
00356       return ERR_VAL;
00357     }
00358   }
00359 #endif /* IP_SOF_BROADCAST */
00360 
00361   if (ip_addr_isany(&pcb->local_ip)) {
00362     /* use outgoing network interface IP address as source address */
00363     src_ip = ip_netif_get_local_ip(netif, dst_ip);
00364 #if LWIP_IPV6
00365     if (src_ip == NULL) {
00366       if (q != p) {
00367         pbuf_free(q);
00368       }
00369       return ERR_RTE;
00370     }
00371 #endif /* LWIP_IPV6 */
00372   } else {
00373     /* use RAW PCB local IP address as source address */
00374     src_ip = &pcb->local_ip;
00375   }
00376 
00377 #if LWIP_IPV6
00378   /* If requested, based on the IPV6_CHECKSUM socket option per RFC3542,
00379      compute the checksum and update the checksum in the payload. */
00380   if (IP_IS_V6(dst_ip) && pcb->chksum_reqd) {
00381     u16_t chksum = ip6_chksum_pseudo(p, pcb->protocol, p->tot_len, ip_2_ip6(src_ip), ip_2_ip6(dst_ip));
00382     LWIP_ASSERT("Checksum must fit into first pbuf", p->len >= (pcb->chksum_offset + 2));
00383     SMEMCPY(((u8_t *)p->payload) + pcb->chksum_offset, &chksum, sizeof(u16_t));
00384   }
00385 #endif
00386 
00387   NETIF_SET_HWADDRHINT(netif, &pcb->addr_hint);
00388   err = ip_output_if(q, src_ip, dst_ip, pcb->ttl, pcb->tos, pcb->protocol, netif);
00389   NETIF_SET_HWADDRHINT(netif, NULL);
00390 
00391   /* did we chain a header earlier? */
00392   if (q != p) {
00393     /* free the header */
00394     pbuf_free(q);
00395   }
00396   return err;
00397 }
00398 
00399 /**
00400  * @ingroup raw_raw
00401  * Send the raw IP packet to the address given by raw_connect()
00402  *
00403  * @param pcb the raw pcb which to send
00404  * @param p the IP payload to send
00405  *
00406  */
00407 err_t
00408 raw_send(struct raw_pcb *pcb, struct pbuf *p)
00409 {
00410   return raw_sendto(pcb, p, &pcb->remote_ip);
00411 }
00412 
00413 /**
00414  * @ingroup raw_raw
00415  * Remove an RAW PCB.
00416  *
00417  * @param pcb RAW PCB to be removed. The PCB is removed from the list of
00418  * RAW PCB's and the data structure is freed from memory.
00419  *
00420  * @see raw_new()
00421  */
00422 void
00423 raw_remove(struct raw_pcb *pcb)
00424 {
00425   struct raw_pcb *pcb2;
00426   /* pcb to be removed is first in list? */
00427   if (raw_pcbs == pcb) {
00428     /* make list start at 2nd pcb */
00429     raw_pcbs = raw_pcbs->next;
00430     /* pcb not 1st in list */
00431   } else {
00432     for (pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
00433       /* find pcb in raw_pcbs list */
00434       if (pcb2->next != NULL && pcb2->next == pcb) {
00435         /* remove pcb from list */
00436         pcb2->next = pcb->next;
00437         break;
00438       }
00439     }
00440   }
00441   memp_free(MEMP_RAW_PCB, pcb);
00442 }
00443 
00444 /**
00445  * @ingroup raw_raw
00446  * Create a RAW PCB.
00447  *
00448  * @return The RAW PCB which was created. NULL if the PCB data structure
00449  * could not be allocated.
00450  *
00451  * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
00452  *
00453  * @see raw_remove()
00454  */
00455 struct raw_pcb *
00456 raw_new(u8_t proto)
00457 {
00458   struct raw_pcb *pcb;
00459 
00460   LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
00461 
00462   pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
00463   /* could allocate RAW PCB? */
00464   if (pcb != NULL) {
00465     /* initialize PCB to all zeroes */
00466     memset(pcb, 0, sizeof(struct raw_pcb));
00467     pcb->protocol = proto;
00468     pcb->ttl = RAW_TTL;
00469     pcb->next = raw_pcbs;
00470     raw_pcbs = pcb;
00471   }
00472   return pcb;
00473 }
00474 
00475 /**
00476  * @ingroup raw_raw
00477  * Create a RAW PCB for specific IP type.
00478  *
00479  * @return The RAW PCB which was created. NULL if the PCB data structure
00480  * could not be allocated.
00481  *
00482  * @param type IP address type, see IPADDR_TYPE_XX definitions.
00483  * @param proto the protocol number (next header) of the IPv6 packet payload
00484  *              (e.g. IP6_NEXTH_ICMP6)
00485  *
00486  * @see raw_remove()
00487  */
00488 struct raw_pcb *
00489 raw_new_ip_type(u8_t type, u8_t proto)
00490 {
00491   struct raw_pcb *pcb;
00492   pcb = raw_new(proto);
00493 #if LWIP_IPV4 && LWIP_IPV6
00494   if (pcb != NULL) {
00495     IP_SET_TYPE_VAL(pcb->local_ip,  type);
00496     IP_SET_TYPE_VAL(pcb->remote_ip, type);
00497   }
00498 #else /* LWIP_IPV4 && LWIP_IPV6 */
00499   LWIP_UNUSED_ARG(type);
00500 #endif /* LWIP_IPV4 && LWIP_IPV6 */
00501   return pcb;
00502 }
00503 
00504 #endif /* LWIP_RAW */