Stripped down version of Segundos NetService library (http://mbed.org/users/segundo/libraries/NetServices ). I have removed all NetServices, and all functions which had been disabled. Use this version when you need only pure TCP or UDP functions - this library compiles faster.
Dependents: christmasLights device_server pop3demo device_server_udp ... more
Diff: lwip/core/ipv4/ip_frag.c
- Revision:
- 1:9d93f4dc2f46
- Parent:
- 0:8b387bed54c2
--- a/lwip/core/ipv4/ip_frag.c Mon Jan 10 21:03:11 2011 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,863 +0,0 @@ -/** - * @file - * This is the IPv4 packet segmentation and reassembly implementation. - * - */ - -/* - * 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: Jani Monoses <jani@iv.ro> - * Simon Goldschmidt - * original reassembly code by Adam Dunkels <adam@sics.se> - * - */ - -#include "lwip/opt.h" -#include "lwip/ip_frag.h" -#include "lwip/def.h" -#include "lwip/inet_chksum.h" -#include "lwip/netif.h" -#include "lwip/snmp.h" -#include "lwip/stats.h" -#include "lwip/icmp.h" - -#include <string.h> - -#if IP_REASSEMBLY -/** - * The IP reassembly code currently has the following limitations: - * - IP header options are not supported - * - fragments must not overlap (e.g. due to different routes), - * currently, overlapping or duplicate fragments are thrown away - * if IP_REASS_CHECK_OVERLAP=1 (the default)! - * - * @todo: work with IP header options - */ - -/** Setting this to 0, you can turn off checking the fragments for overlapping - * regions. The code gets a little smaller. Only use this if you know that - * overlapping won't occur on your network! */ -#ifndef IP_REASS_CHECK_OVERLAP -#define IP_REASS_CHECK_OVERLAP 1 -#endif /* IP_REASS_CHECK_OVERLAP */ - -/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is - * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller. - * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA - * is set to 1, so one datagram can be reassembled at a time, only. */ -#ifndef IP_REASS_FREE_OLDEST -#define IP_REASS_FREE_OLDEST 1 -#endif /* IP_REASS_FREE_OLDEST */ - -#define IP_REASS_FLAG_LASTFRAG 0x01 - -/** This is a helper struct which holds the starting - * offset and the ending offset of this fragment to - * easily chain the fragments. - * It has the same packing requirements as the IP header, since it replaces - * the IP header in memory in incoming fragments (after copying it) to keep - * track of the various fragments. (-> If the IP header doesn't need packing, - * this struct doesn't need packing, too.) - */ -#ifdef PACK_STRUCT_USE_INCLUDES -# include "arch/bpstruct.h" -#endif -PACK_STRUCT_BEGIN -struct ip_reass_helper { - PACK_STRUCT_FIELD(struct pbuf *next_pbuf); - PACK_STRUCT_FIELD(u16_t start); - PACK_STRUCT_FIELD(u16_t end); -} PACK_STRUCT_STRUCT; -PACK_STRUCT_END -#ifdef PACK_STRUCT_USE_INCLUDES -# include "arch/epstruct.h" -#endif - -#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB) \ - (ip_addr_cmp(&(iphdrA)->src, &(iphdrB)->src) && \ - ip_addr_cmp(&(iphdrA)->dest, &(iphdrB)->dest) && \ - IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0 - -/* global variables */ -static struct ip_reassdata *reassdatagrams; -static u16_t ip_reass_pbufcount; - -/* function prototypes */ -static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev); -static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev); - -/** - * Reassembly timer base function - * for both NO_SYS == 0 and 1 (!). - * - * Should be called every 1000 msec (defined by IP_TMR_INTERVAL). - */ -void -ip_reass_tmr(void) -{ - struct ip_reassdata *r, *prev = NULL; - - r = reassdatagrams; - while (r != NULL) { - /* Decrement the timer. Once it reaches 0, - * clean up the incomplete fragment assembly */ - if (r->timer > 0) { - r->timer--; - LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n",(u16_t)r->timer)); - prev = r; - r = r->next; - } else { - /* reassembly timed out */ - struct ip_reassdata *tmp; - LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n")); - tmp = r; - /* get the next pointer before freeing */ - r = r->next; - /* free the helper struct and all enqueued pbufs */ - ip_reass_free_complete_datagram(tmp, prev); - } - } -} - -/** - * Free a datagram (struct ip_reassdata) and all its pbufs. - * Updates the total count of enqueued pbufs (ip_reass_pbufcount), - * SNMP counters and sends an ICMP time exceeded packet. - * - * @param ipr datagram to free - * @param prev the previous datagram in the linked list - * @return the number of pbufs freed - */ -static int -ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev) -{ - u16_t pbufs_freed = 0; - u8_t clen; - struct pbuf *p; - struct ip_reass_helper *iprh; - - LWIP_ASSERT("prev != ipr", prev != ipr); - if (prev != NULL) { - LWIP_ASSERT("prev->next == ipr", prev->next == ipr); - } - - snmp_inc_ipreasmfails(); -#if LWIP_ICMP - iprh = (struct ip_reass_helper *)ipr->p->payload; - if (iprh->start == 0) { - /* The first fragment was received, send ICMP time exceeded. */ - /* First, de-queue the first pbuf from r->p. */ - p = ipr->p; - ipr->p = iprh->next_pbuf; - /* Then, copy the original header into it. */ - SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN); - icmp_time_exceeded(p, ICMP_TE_FRAG); - clen = pbuf_clen(p); - LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff); - pbufs_freed += clen; - pbuf_free(p); - } -#endif /* LWIP_ICMP */ - - /* First, free all received pbufs. The individual pbufs need to be released - separately as they have not yet been chained */ - p = ipr->p; - while (p != NULL) { - struct pbuf *pcur; - iprh = (struct ip_reass_helper *)p->payload; - pcur = p; - /* get the next pointer before freeing */ - p = iprh->next_pbuf; - clen = pbuf_clen(pcur); - LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff); - pbufs_freed += clen; - pbuf_free(pcur); - } - /* Then, unchain the struct ip_reassdata from the list and free it. */ - ip_reass_dequeue_datagram(ipr, prev); - LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= pbufs_freed); - ip_reass_pbufcount -= pbufs_freed; - - return pbufs_freed; -} - -#if IP_REASS_FREE_OLDEST -/** - * Free the oldest datagram to make room for enqueueing new fragments. - * The datagram 'fraghdr' belongs to is not freed! - * - * @param fraghdr IP header of the current fragment - * @param pbufs_needed number of pbufs needed to enqueue - * (used for freeing other datagrams if not enough space) - * @return the number of pbufs freed - */ -static int -ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed) -{ - /* @todo Can't we simply remove the last datagram in the - * linked list behind reassdatagrams? - */ - struct ip_reassdata *r, *oldest, *prev; - int pbufs_freed = 0, pbufs_freed_current; - int other_datagrams; - - /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs, - * but don't free the datagram that 'fraghdr' belongs to! */ - do { - oldest = NULL; - prev = NULL; - other_datagrams = 0; - r = reassdatagrams; - while (r != NULL) { - if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) { - /* Not the same datagram as fraghdr */ - other_datagrams++; - if (oldest == NULL) { - oldest = r; - } else if (r->timer <= oldest->timer) { - /* older than the previous oldest */ - oldest = r; - } - } - if (r->next != NULL) { - prev = r; - } - r = r->next; - } - if (oldest != NULL) { - pbufs_freed_current = ip_reass_free_complete_datagram(oldest, prev); - pbufs_freed += pbufs_freed_current; - } - } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1)); - return pbufs_freed; -} -#endif /* IP_REASS_FREE_OLDEST */ - -/** - * Enqueues a new fragment into the fragment queue - * @param fraghdr points to the new fragments IP hdr - * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space) - * @return A pointer to the queue location into which the fragment was enqueued - */ -static struct ip_reassdata* -ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen) -{ - struct ip_reassdata* ipr; - /* No matching previous fragment found, allocate a new reassdata struct */ - ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA); - if (ipr == NULL) { -#if IP_REASS_FREE_OLDEST - if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) { - ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA); - } - if (ipr == NULL) -#endif /* IP_REASS_FREE_OLDEST */ - { - IPFRAG_STATS_INC(ip_frag.memerr); - LWIP_DEBUGF(IP_REASS_DEBUG,("Failed to alloc reassdata struct\n")); - return NULL; - } - } - memset(ipr, 0, sizeof(struct ip_reassdata)); - ipr->timer = IP_REASS_MAXAGE; - - /* enqueue the new structure to the front of the list */ - ipr->next = reassdatagrams; - reassdatagrams = ipr; - /* copy the ip header for later tests and input */ - /* @todo: no ip options supported? */ - SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN); - return ipr; -} - -/** - * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs. - * @param ipr points to the queue entry to dequeue - */ -static void -ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev) -{ - - /* dequeue the reass struct */ - if (reassdatagrams == ipr) { - /* it was the first in the list */ - reassdatagrams = ipr->next; - } else { - /* it wasn't the first, so it must have a valid 'prev' */ - LWIP_ASSERT("sanity check linked list", prev != NULL); - prev->next = ipr->next; - } - - /* now we can free the ip_reass struct */ - memp_free(MEMP_REASSDATA, ipr); -} - -/** - * Chain a new pbuf into the pbuf list that composes the datagram. The pbuf list - * will grow over time as new pbufs are rx. - * Also checks that the datagram passes basic continuity checks (if the last - * fragment was received at least once). - * @param root_p points to the 'root' pbuf for the current datagram being assembled. - * @param new_p points to the pbuf for the current fragment - * @return 0 if invalid, >0 otherwise - */ -static int -ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p) -{ - struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL; - struct pbuf *q; - u16_t offset,len; - struct ip_hdr *fraghdr; - int valid = 1; - - /* Extract length and fragment offset from current fragment */ - fraghdr = (struct ip_hdr*)new_p->payload; - len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4; - offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8; - - /* overwrite the fragment's ip header from the pbuf with our helper struct, - * and setup the embedded helper structure. */ - /* make sure the struct ip_reass_helper fits into the IP header */ - LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN", - sizeof(struct ip_reass_helper) <= IP_HLEN); - iprh = (struct ip_reass_helper*)new_p->payload; - iprh->next_pbuf = NULL; - iprh->start = offset; - iprh->end = offset + len; - - /* Iterate through until we either get to the end of the list (append), - * or we find on with a larger offset (insert). */ - for (q = ipr->p; q != NULL;) { - iprh_tmp = (struct ip_reass_helper*)q->payload; - if (iprh->start < iprh_tmp->start) { - /* the new pbuf should be inserted before this */ - iprh->next_pbuf = q; - if (iprh_prev != NULL) { - /* not the fragment with the lowest offset */ -#if IP_REASS_CHECK_OVERLAP - if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) { - /* fragment overlaps with previous or following, throw away */ - goto freepbuf; - } -#endif /* IP_REASS_CHECK_OVERLAP */ - iprh_prev->next_pbuf = new_p; - } else { - /* fragment with the lowest offset */ - ipr->p = new_p; - } - break; - } else if(iprh->start == iprh_tmp->start) { - /* received the same datagram twice: no need to keep the datagram */ - goto freepbuf; -#if IP_REASS_CHECK_OVERLAP - } else if(iprh->start < iprh_tmp->end) { - /* overlap: no need to keep the new datagram */ - goto freepbuf; -#endif /* IP_REASS_CHECK_OVERLAP */ - } else { - /* Check if the fragments received so far have no wholes. */ - if (iprh_prev != NULL) { - if (iprh_prev->end != iprh_tmp->start) { - /* There is a fragment missing between the current - * and the previous fragment */ - valid = 0; - } - } - } - q = iprh_tmp->next_pbuf; - iprh_prev = iprh_tmp; - } - - /* If q is NULL, then we made it to the end of the list. Determine what to do now */ - if (q == NULL) { - if (iprh_prev != NULL) { - /* this is (for now), the fragment with the highest offset: - * chain it to the last fragment */ -#if IP_REASS_CHECK_OVERLAP - LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start); -#endif /* IP_REASS_CHECK_OVERLAP */ - iprh_prev->next_pbuf = new_p; - if (iprh_prev->end != iprh->start) { - valid = 0; - } - } else { -#if IP_REASS_CHECK_OVERLAP - LWIP_ASSERT("no previous fragment, this must be the first fragment!", - ipr->p == NULL); -#endif /* IP_REASS_CHECK_OVERLAP */ - /* this is the first fragment we ever received for this ip datagram */ - ipr->p = new_p; - } - } - - /* At this point, the validation part begins: */ - /* If we already received the last fragment */ - if ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0) { - /* and had no wholes so far */ - if (valid) { - /* then check if the rest of the fragments is here */ - /* Check if the queue starts with the first datagram */ - if (((struct ip_reass_helper*)ipr->p->payload)->start != 0) { - valid = 0; - } else { - /* and check that there are no wholes after this datagram */ - iprh_prev = iprh; - q = iprh->next_pbuf; - while (q != NULL) { - iprh = (struct ip_reass_helper*)q->payload; - if (iprh_prev->end != iprh->start) { - valid = 0; - break; - } - iprh_prev = iprh; - q = iprh->next_pbuf; - } - /* if still valid, all fragments are received - * (because to the MF==0 already arrived */ - if (valid) { - LWIP_ASSERT("sanity check", ipr->p != NULL); - LWIP_ASSERT("sanity check", - ((struct ip_reass_helper*)ipr->p->payload) != iprh); - LWIP_ASSERT("validate_datagram:next_pbuf!=NULL", - iprh->next_pbuf == NULL); - LWIP_ASSERT("validate_datagram:datagram end!=datagram len", - iprh->end == ipr->datagram_len); - } - } - } - /* If valid is 0 here, there are some fragments missing in the middle - * (since MF == 0 has already arrived). Such datagrams simply time out if - * no more fragments are received... */ - return valid; - } - /* If we come here, not all fragments were received, yet! */ - return 0; /* not yet valid! */ -#if IP_REASS_CHECK_OVERLAP -freepbuf: - ip_reass_pbufcount -= pbuf_clen(new_p); - pbuf_free(new_p); - return 0; -#endif /* IP_REASS_CHECK_OVERLAP */ -} - -/** - * Reassembles incoming IP fragments into an IP datagram. - * - * @param p points to a pbuf chain of the fragment - * @return NULL if reassembly is incomplete, ? otherwise - */ -struct pbuf * -ip_reass(struct pbuf *p) -{ - struct pbuf *r; - struct ip_hdr *fraghdr; - struct ip_reassdata *ipr; - struct ip_reass_helper *iprh; - u16_t offset, len; - u8_t clen; - struct ip_reassdata *ipr_prev = NULL; - - IPFRAG_STATS_INC(ip_frag.recv); - snmp_inc_ipreasmreqds(); - - fraghdr = (struct ip_hdr*)p->payload; - - if ((IPH_HL(fraghdr) * 4) != IP_HLEN) { - LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: IP options currently not supported!\n")); - IPFRAG_STATS_INC(ip_frag.err); - goto nullreturn; - } - - offset = (ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) * 8; - len = ntohs(IPH_LEN(fraghdr)) - IPH_HL(fraghdr) * 4; - - /* Check if we are allowed to enqueue more datagrams. */ - clen = pbuf_clen(p); - if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) { -#if IP_REASS_FREE_OLDEST - if (!ip_reass_remove_oldest_datagram(fraghdr, clen) || - ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS)) -#endif /* IP_REASS_FREE_OLDEST */ - { - /* No datagram could be freed and still too many pbufs enqueued */ - LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n", - ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS)); - IPFRAG_STATS_INC(ip_frag.memerr); - /* @todo: send ICMP time exceeded here? */ - /* drop this pbuf */ - goto nullreturn; - } - } - - /* Look for the datagram the fragment belongs to in the current datagram queue, - * remembering the previous in the queue for later dequeueing. */ - for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) { - /* Check if the incoming fragment matches the one currently present - in the reassembly buffer. If so, we proceed with copying the - fragment into the buffer. */ - if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) { - LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass: matching previous fragment ID=%"X16_F"\n", - ntohs(IPH_ID(fraghdr)))); - IPFRAG_STATS_INC(ip_frag.cachehit); - break; - } - ipr_prev = ipr; - } - - if (ipr == NULL) { - /* Enqueue a new datagram into the datagram queue */ - ipr = ip_reass_enqueue_new_datagram(fraghdr, clen); - /* Bail if unable to enqueue */ - if(ipr == NULL) { - goto nullreturn; - } - } else { - if (((ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) && - ((ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) { - /* ipr->iphdr is not the header from the first fragment, but fraghdr is - * -> copy fraghdr into ipr->iphdr since we want to have the header - * of the first fragment (for ICMP time exceeded and later, for copying - * all options, if supported)*/ - SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN); - } - } - /* Track the current number of pbufs current 'in-flight', in order to limit - the number of fragments that may be enqueued at any one time */ - ip_reass_pbufcount += clen; - - /* At this point, we have either created a new entry or pointing - * to an existing one */ - - /* check for 'no more fragments', and update queue entry*/ - if ((IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0) { - ipr->flags |= IP_REASS_FLAG_LASTFRAG; - ipr->datagram_len = offset + len; - LWIP_DEBUGF(IP_REASS_DEBUG, - ("ip_reass: last fragment seen, total len %"S16_F"\n", - ipr->datagram_len)); - } - /* find the right place to insert this pbuf */ - /* @todo: trim pbufs if fragments are overlapping */ - if (ip_reass_chain_frag_into_datagram_and_validate(ipr, p)) { - /* the totally last fragment (flag more fragments = 0) was received at least - * once AND all fragments are received */ - ipr->datagram_len += IP_HLEN; - - /* save the second pbuf before copying the header over the pointer */ - r = ((struct ip_reass_helper*)ipr->p->payload)->next_pbuf; - - /* copy the original ip header back to the first pbuf */ - fraghdr = (struct ip_hdr*)(ipr->p->payload); - SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN); - IPH_LEN_SET(fraghdr, htons(ipr->datagram_len)); - IPH_OFFSET_SET(fraghdr, 0); - IPH_CHKSUM_SET(fraghdr, 0); - /* @todo: do we need to set calculate the correct checksum? */ - IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN)); - - p = ipr->p; - - /* chain together the pbufs contained within the reass_data list. */ - while(r != NULL) { - iprh = (struct ip_reass_helper*)r->payload; - - /* hide the ip header for every succeding fragment */ - pbuf_header(r, -IP_HLEN); - pbuf_cat(p, r); - r = iprh->next_pbuf; - } - /* release the sources allocate for the fragment queue entry */ - ip_reass_dequeue_datagram(ipr, ipr_prev); - - /* and adjust the number of pbufs currently queued for reassembly. */ - ip_reass_pbufcount -= pbuf_clen(p); - - /* Return the pbuf chain */ - return p; - } - /* the datagram is not (yet?) reassembled completely */ - LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount)); - return NULL; - -nullreturn: - LWIP_DEBUGF(IP_REASS_DEBUG,("ip_reass: nullreturn\n")); - IPFRAG_STATS_INC(ip_frag.drop); - pbuf_free(p); - return NULL; -} -#endif /* IP_REASSEMBLY */ - -#if IP_FRAG -#if IP_FRAG_USES_STATIC_BUF -static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)]; -#else /* IP_FRAG_USES_STATIC_BUF */ - -#if !LWIP_NETIF_TX_SINGLE_PBUF -/** Allocate a new struct pbuf_custom_ref */ -static struct pbuf_custom_ref* -ip_frag_alloc_pbuf_custom_ref(void) -{ - return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF); -} - -/** Free a struct pbuf_custom_ref */ -static void -ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p) -{ - LWIP_ASSERT("p != NULL", p != NULL); - memp_free(MEMP_FRAG_PBUF, p); -} - -/** Free-callback function to free a 'struct pbuf_custom_ref', called by - * pbuf_free. */ -static void -ipfrag_free_pbuf_custom(struct pbuf *p) -{ - struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p; - LWIP_ASSERT("pcr != NULL", pcr != NULL); - LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p); - if (pcr->original != NULL) { - pbuf_free(pcr->original); - } - ip_frag_free_pbuf_custom_ref(pcr); -} -#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */ -#endif /* IP_FRAG_USES_STATIC_BUF */ - -/** - * Fragment an IP datagram if too large for the netif. - * - * Chop the datagram in MTU sized chunks and send them in order - * by using a fixed size static memory buffer (PBUF_REF) or - * point PBUF_REFs into p (depending on IP_FRAG_USES_STATIC_BUF). - * - * @param p ip packet to send - * @param netif the netif on which to send - * @param dest destination ip address to which to send - * - * @return ERR_OK if sent successfully, err_t otherwise - */ -err_t -ip_frag(struct pbuf *p, struct netif *netif, ip_addr_t *dest) -{ - struct pbuf *rambuf; -#if IP_FRAG_USES_STATIC_BUF - struct pbuf *header; -#else -#if !LWIP_NETIF_TX_SINGLE_PBUF - struct pbuf *newpbuf; -#endif - struct ip_hdr *original_iphdr; -#endif - struct ip_hdr *iphdr; - u16_t nfb; - u16_t left, cop; - u16_t mtu = netif->mtu; - u16_t ofo, omf; - u16_t last; - u16_t poff = IP_HLEN; - u16_t tmp; -#if !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF - u16_t newpbuflen = 0; - u16_t left_to_copy; -#endif - - /* Get a RAM based MTU sized pbuf */ -#if IP_FRAG_USES_STATIC_BUF - /* When using a static buffer, we use a PBUF_REF, which we will - * use to reference the packet (without link header). - * Layer and length is irrelevant. - */ - rambuf = pbuf_alloc(PBUF_LINK, 0, PBUF_REF); - if (rambuf == NULL) { - LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc(PBUF_LINK, 0, PBUF_REF) failed\n")); - return ERR_MEM; - } - rambuf->tot_len = rambuf->len = mtu; - rambuf->payload = LWIP_MEM_ALIGN((void *)buf); - - /* Copy the IP header in it */ - iphdr = (struct ip_hdr *)rambuf->payload; - SMEMCPY(iphdr, p->payload, IP_HLEN); -#else /* IP_FRAG_USES_STATIC_BUF */ - original_iphdr = (struct ip_hdr *)p->payload; - iphdr = original_iphdr; -#endif /* IP_FRAG_USES_STATIC_BUF */ - - /* Save original offset */ - tmp = ntohs(IPH_OFFSET(iphdr)); - ofo = tmp & IP_OFFMASK; - omf = tmp & IP_MF; - - left = p->tot_len - IP_HLEN; - - nfb = (mtu - IP_HLEN) / 8; - - while (left) { - last = (left <= mtu - IP_HLEN); - - /* Set new offset and MF flag */ - tmp = omf | (IP_OFFMASK & (ofo)); - if (!last) { - tmp = tmp | IP_MF; - } - - /* Fill this fragment */ - cop = last ? left : nfb * 8; - -#if IP_FRAG_USES_STATIC_BUF - poff += pbuf_copy_partial(p, (u8_t*)iphdr + IP_HLEN, cop, poff); -#else /* IP_FRAG_USES_STATIC_BUF */ -#if LWIP_NETIF_TX_SINGLE_PBUF - rambuf = pbuf_alloc(PBUF_IP, cop, PBUF_RAM); - if (rambuf == NULL) { - return ERR_MEM; - } - LWIP_ASSERT("this needs a pbuf in one piece!", - (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL)); - poff += pbuf_copy_partial(p, rambuf->payload, cop, poff); - /* make room for the IP header */ - if(pbuf_header(rambuf, IP_HLEN)) { - pbuf_free(rambuf); - return ERR_MEM; - } - /* fill in the IP header */ - SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN); - iphdr = rambuf->payload; -#else /* LWIP_NETIF_TX_SINGLE_PBUF */ - /* When not using a static buffer, create a chain of pbufs. - * The first will be a PBUF_RAM holding the link and IP header. - * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged, - * but limited to the size of an mtu. - */ - rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM); - if (rambuf == NULL) { - return ERR_MEM; - } - LWIP_ASSERT("this needs a pbuf in one piece!", - (p->len >= (IP_HLEN))); - SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN); - iphdr = (struct ip_hdr *)rambuf->payload; - - /* Can just adjust p directly for needed offset. */ - p->payload = (u8_t *)p->payload + poff; - p->len -= poff; - - left_to_copy = cop; - while (left_to_copy) { - struct pbuf_custom_ref *pcr; - newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len; - /* Is this pbuf already empty? */ - if (!newpbuflen) { - p = p->next; - continue; - } - pcr = ip_frag_alloc_pbuf_custom_ref(); - if (pcr == NULL) { - pbuf_free(rambuf); - return ERR_MEM; - } - /* Mirror this pbuf, although we might not need all of it. */ - newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen); - if (newpbuf == NULL) { - ip_frag_free_pbuf_custom_ref(pcr); - pbuf_free(rambuf); - return ERR_MEM; - } - pbuf_ref(p); - pcr->original = p; - pcr->pc.custom_free_function = ipfrag_free_pbuf_custom; - - /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain - * so that it is removed when pbuf_dechain is later called on rambuf. - */ - pbuf_cat(rambuf, newpbuf); - left_to_copy -= newpbuflen; - if (left_to_copy) { - p = p->next; - } - } - poff = newpbuflen; -#endif /* LWIP_NETIF_TX_SINGLE_PBUF */ -#endif /* IP_FRAG_USES_STATIC_BUF */ - - /* Correct header */ - IPH_OFFSET_SET(iphdr, htons(tmp)); - IPH_LEN_SET(iphdr, htons(cop + IP_HLEN)); - IPH_CHKSUM_SET(iphdr, 0); - IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN)); - -#if IP_FRAG_USES_STATIC_BUF - if (last) { - pbuf_realloc(rambuf, left + IP_HLEN); - } - - /* This part is ugly: we alloc a RAM based pbuf for - * the link level header for each chunk and then - * free it.A PBUF_ROM style pbuf for which pbuf_header - * worked would make things simpler. - */ - header = pbuf_alloc(PBUF_LINK, 0, PBUF_RAM); - if (header != NULL) { - pbuf_chain(header, rambuf); - netif->output(netif, header, dest); - IPFRAG_STATS_INC(ip_frag.xmit); - snmp_inc_ipfragcreates(); - pbuf_free(header); - } else { - LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_frag: pbuf_alloc() for header failed\n")); - pbuf_free(rambuf); - return ERR_MEM; - } -#else /* IP_FRAG_USES_STATIC_BUF */ - /* No need for separate header pbuf - we allowed room for it in rambuf - * when allocated. - */ - netif->output(netif, rambuf, dest); - IPFRAG_STATS_INC(ip_frag.xmit); - - /* Unfortunately we can't reuse rambuf - the hardware may still be - * using the buffer. Instead we free it (and the ensuing chain) and - * recreate it next time round the loop. If we're lucky the hardware - * will have already sent the packet, the free will really free, and - * there will be zero memory penalty. - */ - - pbuf_free(rambuf); -#endif /* IP_FRAG_USES_STATIC_BUF */ - left -= cop; - ofo += nfb; - } -#if IP_FRAG_USES_STATIC_BUF - pbuf_free(rambuf); -#endif /* IP_FRAG_USES_STATIC_BUF */ - snmp_inc_ipfragoks(); - return ERR_OK; -} -#endif /* IP_FRAG */