ip6_frag.h

00001 /**
00002  * @file
00003  *
00004  * IPv6 fragmentation and reassembly.
00005  */
00006 
00007 /*
00008  * Copyright (c) 2010 Inico Technologies Ltd.
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without modification,
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  *
00035  * Author: Ivan Delamer <delamer@inicotech.com>
00036  *
00037  *
00038  * Please coordinate changes and requests with Ivan Delamer
00039  * <delamer@inicotech.com>
00040  */
00041 #ifndef LWIP_HDR_IP6_FRAG_H
00042 #define LWIP_HDR_IP6_FRAG_H
00043 
00044 #include "lwip/opt.h"
00045 #include "lwip/pbuf.h"
00046 #include "lwip/ip6_addr.h"
00047 #include "lwip/ip6.h"
00048 #include "lwip/netif.h"
00049 
00050 #ifdef __cplusplus
00051 extern "C" {
00052 #endif
00053 
00054 
00055 #if LWIP_IPV6 && LWIP_IPV6_REASS  /* don't build if not configured for use in lwipopts.h */
00056 
00057 /** The IPv6 reassembly timer interval in milliseconds. */
00058 #define IP6_REASS_TMR_INTERVAL 1000
00059 
00060 /** IP6_FRAG_COPYHEADER==1: for platforms where sizeof(void*) > 4, "struct
00061  * ip6_reass_helper" is too large to be stored in the IPv6 fragment header, and
00062  * will bleed into the header before it, which may be the IPv6 header or an
00063  * extension header. This means that for each first fragment packet, we need to
00064  * 1) make a copy of some IPv6 header fields (src+dest) that we need later on,
00065  * just in case we do overwrite part of the IPv6 header, and 2) make a copy of
00066  * the header data that we overwrote, so that we can restore it before either
00067  * completing reassembly or sending an ICMPv6 reply. The last part is true even
00068  * if this setting is disabled, but if it is enabled, we need to save a bit
00069  * more data (up to the size of a pointer) because we overwrite more. */
00070 #ifndef IPV6_FRAG_COPYHEADER
00071 #define IPV6_FRAG_COPYHEADER   0
00072 #endif
00073 
00074 /* With IPV6_FRAG_COPYHEADER==1, a helper structure may (or, depending on the
00075  * presence of extensions, may not) overwrite part of the IP header. Therefore,
00076  * we copy the fields that we need from the IP header for as long as the helper
00077  * structure may still be in place. This is easier than temporarily restoring
00078  * those fields in the IP header each time we need to perform checks on them. */
00079 #if IPV6_FRAG_COPYHEADER
00080 #define IPV6_FRAG_SRC(ipr) ((ipr)->src)
00081 #define IPV6_FRAG_DEST(ipr) ((ipr)->dest)
00082 #else /* IPV6_FRAG_COPYHEADER */
00083 #define IPV6_FRAG_SRC(ipr) ((ipr)->iphdr->src)
00084 #define IPV6_FRAG_DEST(ipr) ((ipr)->iphdr->dest)
00085 #endif /* IPV6_FRAG_COPYHEADER */
00086 
00087 /** IPv6 reassembly helper struct.
00088  * This is exported because memp needs to know the size.
00089  */
00090 struct ip6_reassdata {
00091   struct ip6_reassdata *next;
00092   struct pbuf *p;
00093   struct ip6_hdr *iphdr; /* pointer to the first (original) IPv6 header */
00094 #if IPV6_FRAG_COPYHEADER
00095   ip6_addr_p_t src; /* copy of the source address in the IP header */
00096   ip6_addr_p_t dest; /* copy of the destination address in the IP header */
00097   /* This buffer (for the part of the original header that we overwrite) will
00098    * be slightly oversized, but we cannot compute the exact size from here. */
00099   u8_t orig_hdr[sizeof(struct ip6_frag_hdr) + sizeof(void*)];
00100 #else /* IPV6_FRAG_COPYHEADER */
00101   /* In this case we still need the buffer, for sending ICMPv6 replies. */
00102   u8_t orig_hdr[sizeof(struct ip6_frag_hdr)];
00103 #endif /* IPV6_FRAG_COPYHEADER */
00104   u32_t identification;
00105   u16_t datagram_len;
00106   u8_t nexth;
00107   u8_t timer;
00108 #if LWIP_IPV6_SCOPES
00109   u8_t src_zone; /* zone of original packet's source address */
00110   u8_t dest_zone; /* zone of original packet's destination address */
00111 #endif /* LWIP_IPV6_SCOPES */
00112 };
00113 
00114 #define ip6_reass_init() /* Compatibility define */
00115 void ip6_reass_tmr(void);
00116 struct pbuf *ip6_reass(struct pbuf *p);
00117 
00118 #endif /* LWIP_IPV6 && LWIP_IPV6_REASS */
00119 
00120 #if LWIP_IPV6 && LWIP_IPV6_FRAG  /* don't build if not configured for use in lwipopts.h */
00121 
00122 #ifndef LWIP_PBUF_CUSTOM_REF_DEFINED
00123 #define LWIP_PBUF_CUSTOM_REF_DEFINED
00124 /** A custom pbuf that holds a reference to another pbuf, which is freed
00125  * when this custom pbuf is freed. This is used to create a custom PBUF_REF
00126  * that points into the original pbuf. */
00127 struct pbuf_custom_ref {
00128   /** 'base class' */
00129   struct pbuf_custom pc;
00130   /** pointer to the original pbuf that is referenced */
00131   struct pbuf *original;
00132 };
00133 #endif /* LWIP_PBUF_CUSTOM_REF_DEFINED */
00134 
00135 err_t ip6_frag(struct pbuf *p, struct netif *netif, const ip6_addr_t *dest);
00136 
00137 #endif /* LWIP_IPV6 && LWIP_IPV6_FRAG */
00138 
00139 
00140 #ifdef __cplusplus
00141 }
00142 #endif
00143 
00144 #endif /* LWIP_HDR_IP6_FRAG_H */