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incubator-nuttx/net/ipfrag/ipv6_frag.c

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/****************************************************************************
* net/ipfrag/ipv6_frag.c
* Handling incoming IPv6 fragment input
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET_IPv6) && defined (CONFIG_NET_IPFRAG)
#include <sys/ioctl.h>
#include <stdint.h>
#include <stdlib.h>
#include <debug.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <net/if.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/netstats.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/ipv6ext.h>
#include "netdev/netdev.h"
#include "inet/inet.h"
#include "ipfrag.h"
/****************************************************************************
* Private Data
****************************************************************************/
/* The increasing number used for the IP ID field of IPv6 Fragment Header. */
static uint32_t g_ipv6id;
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int32_t ipv6_fragin_getinfo(FAR struct iob_s *iob,
FAR struct ip_fraglink_s *fraglink);
static uint32_t ipv6_fragin_reassemble(FAR struct ip_fragsnode_s *node);
static inline void
ipv6_fragout_buildipv6header(FAR struct ipv6_hdr_s *ref,
FAR struct ipv6_hdr_s *ipv6,
uint16_t hdrlen, uint16_t datalen,
uint16_t nxthdroff, uint16_t nxtprot);
static inline void
ipv6_fragout_buildipv6fragheader(FAR struct ipv6_fragment_extension_s *frag,
uint8_t nxthdr, uint16_t ipoff,
uint32_t ipid);
static uint16_t ipv6_fragout_getunfraginfo(FAR struct iob_s *iob,
uint16_t *hdroff,
uint16_t *hdrtype);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ipv6_fragin_getinfo
*
* Description:
* Polulate fragment information from the input ipv6 packet data.
*
* Input Parameters:
* iob - An IPv6 fragment
* fraglink - node of the lower-level linked list, it maintains information
* of one fragment
*
* Returned Value:
* OK - Got fragment information.
* EINVAL - The input ipv6 packet is not a fragment.
*
****************************************************************************/
static int32_t ipv6_fragin_getinfo(FAR struct iob_s *iob,
FAR struct ip_fraglink_s *fraglink)
{
FAR struct ipv6_hdr_s *ipv6 = (FAR struct ipv6_hdr_s *)
(iob->io_data + iob->io_offset);
FAR struct ipv6_extension_s *exthdr;
FAR uint8_t *payload;
uint16_t paylen;
uint8_t nxthdr;
paylen = ((uint16_t)ipv6->len[0] << 8) + (uint16_t)ipv6->len[1];
payload = (FAR uint8_t *)(ipv6 + 1);
exthdr = (FAR struct ipv6_extension_s *)payload;
nxthdr = ipv6->proto;
while (nxthdr != NEXT_FRAGMENT_EH && ipv6_exthdr(nxthdr))
{
uint16_t extlen;
exthdr = (FAR struct ipv6_extension_s *)payload;
extlen = EXTHDR_LEN((unsigned int)exthdr->len);
payload += extlen;
paylen -= extlen;
nxthdr = exthdr->nxthdr;
};
if (nxthdr == NEXT_FRAGMENT_EH)
{
FAR struct ipv6_fragment_extension_s *fraghdr;
fraghdr = (FAR struct ipv6_fragment_extension_s *)exthdr;
/* Cut the size of fragment header, notice fragment header don't has a
* length filed.
*/
paylen -= EXTHDR_FRAG_LEN;
fraglink->flink = NULL;
fraglink->fragsnode = NULL;
fraglink->isipv4 = FALSE;
fraglink->fragoff = (fraghdr->msoffset << 8) + fraghdr->lsoffset;
fraglink->morefrags = fraglink->fragoff & 0x1;
fraglink->fragoff &= 0xfff8;
fraglink->fraglen = paylen;
fraglink->ipid = NTOHL((*(uint16_t *)(&fraghdr->id[0]) << 16) +
*(uint16_t *)(&fraghdr->id[2]));
fraglink->frag = iob;
return OK;
}
else
{
return -EINVAL;
}
}
/****************************************************************************
* Name: ipv6_fragin_reassemble
*
* Description:
* Reassemble all ipv6 fragments to build an IP frame.
*
* Input Parameters:
* node - node of the upper-level linked list, it maintains
* information about all fragments belonging to an IP datagram
*
* Returned Value:
* The length of the reassembled IP frame
*
****************************************************************************/
static uint32_t ipv6_fragin_reassemble(FAR struct ip_fragsnode_s *node)
{
FAR struct iob_s *head = NULL;
FAR struct ipv6_hdr_s *ipv6;
FAR struct ip_fraglink_s *fraglink;
/* Loop to walk through the fragment list and reassemble those fragments,
* the fraglink list was ordered by fragment offset value
*/
fraglink = node->frags;
node->frags = NULL;
while (fraglink != NULL)
{
FAR uint8_t *payload;
uint8_t nxthdr;
FAR struct iob_s *iob;
FAR struct ip_fraglink_s *linknext;
FAR struct ipv6_extension_s *exthdr;
FAR struct ipv6_fragment_extension_s *fraghdr;
iob = fraglink->frag;
ipv6 = (FAR struct ipv6_hdr_s *)(iob->io_data + iob->io_offset);
payload = (FAR uint8_t *)(ipv6 + 1);
exthdr = (FAR struct ipv6_extension_s *)payload;
nxthdr = ipv6->proto;
/* Find fragment header and the front header which is close to the
* fragment header
*/
while (nxthdr != NEXT_FRAGMENT_EH && ipv6_exthdr(nxthdr))
{
uint16_t extlen;
exthdr = (FAR struct ipv6_extension_s *)payload;
extlen = EXTHDR_LEN((unsigned int)exthdr->len);
payload += extlen;
nxthdr = exthdr->nxthdr;
};
fraghdr = (FAR struct ipv6_fragment_extension_s *)payload;
/* Skip fragment header, notice fragment header don't has a length
* filed
*/
payload += EXTHDR_FRAG_LEN;
if (fraglink->fragoff == 0)
{
/* This is the zero fragment, Set the front header's next header
* filed to the next header value of the fragment header
*/
if (ipv6->proto == NEXT_FRAGMENT_EH)
{
ipv6->proto = fraghdr->nxthdr;
}
else
{
exthdr->nxthdr = fraghdr->nxthdr;
}
/* Remove fragment header and fix up the data length */
memmove(fraghdr, payload,
iob->io_len - (payload - (iob->io_data + iob->io_offset)));
iob->io_len -= EXTHDR_FRAG_LEN;
iob->io_pktlen -= EXTHDR_FRAG_LEN;
/* Remember the head iob */
head = iob;
}
else
{
uint16_t new_off;
/* Fix up the value of offset and length for this none zero
* fragment
*/
new_off = payload - iob->io_data;
iob->io_len -= new_off - iob->io_offset;
iob->io_pktlen -= new_off - iob->io_offset;
iob->io_offset = new_off;
/* Concatenate this iob to the reassembly chain */
iob_concat(head, iob);
}
linknext = fraglink->flink;
kmm_free(fraglink);
fraglink = linknext;
}
/* Remember the reassembled outgoing IP frame */
node->outgoframe = head;
/* Adjust the length value in the IP Header */
ipv6 = (FAR struct ipv6_hdr_s *)(head->io_data + head->io_offset);
ipv6->len[0] = (head->io_pktlen - IPv6_HDRLEN) >> 8;
ipv6->len[1] = (head->io_pktlen - IPv6_HDRLEN) & 0xff;
return head->io_pktlen;
}
/****************************************************************************
* Name: ipv6_fragout_buildipv6header
*
* Description:
* Build IPv6 header for an IPv6 fragment.
*
* Input Parameters:
* ref - The reference IPv6 Header
* ipv6 - The pointer of the newly generated IPv6 Header
* hdrlen - Including the length of IPv6 basic header and all
* extention headers
* datalen - The data length follows the IPv6 basic header
* nxthdroff - The offset of 'next header' to be updated
* nxtprot - The value of 'next header' to be updated
*
* Returned Value:
* None
*
****************************************************************************/
static inline void
ipv6_fragout_buildipv6header(FAR struct ipv6_hdr_s *ref,
FAR struct ipv6_hdr_s *ipv6,
uint16_t hdrlen, uint16_t datalen,
uint16_t nxthdroff, uint16_t nxtprot)
{
if (ref != ipv6)
{
/* Copy unfragmentable header data from reference header */
memcpy(ipv6, ref, hdrlen);
}
/* Update length filed */
ipv6->len[0] = datalen >> 8;
ipv6->len[1] = datalen & 0xff;
/* If extension headers exist, update the Next Header field in the
* last extension header of the unfragmentable part; Otherwise update
* the Next Header field of the basic IPv6 header.
*/
*((uint8_t *)ipv6 + nxthdroff) = nxtprot;
}
/****************************************************************************
* Name: ipv6_fragout_buildipv6fragheader
*
* Description:
* Build IPv6 fragment extension header for an IPv6 fragment.
*
* Input Parameters:
* frag - The pointer of the newly generated IPv6 fragment Header
* nxthdr - The first header type in the fragmentable part
* ipoff - Fragment offset
* ipid - The value of IPv6 IP ID
*
* Returned Value:
* None
*
****************************************************************************/
static inline void
ipv6_fragout_buildipv6fragheader(FAR struct ipv6_fragment_extension_s *frag,
uint8_t nxthdr, uint16_t ipoff,
uint32_t ipid)
{
frag->nxthdr = nxthdr;
frag->reserved = 0;
frag->msoffset = ipoff >> 8;
frag->lsoffset = ipoff & 0xff;
*(uint16_t *)&frag->id[0] = HTONL(ipid) & 0xffff;
*(uint16_t *)&frag->id[2] = HTONL(ipid) >> 16;
}
/****************************************************************************
* Name: ipv6_fragout_getunfraginfo
*
* Description:
* Get the length of Unfragmentable Part of the original ipv6 packet,
* remember the offset and value of nextheader in the last extension
* header of the unfragmentable part.
* Refer to rfc2460, section-4.1, section-4.5
*
* Input Parameters:
* iob - Outgoing data waiting for fragment
* hdroff - The offset of the last next header position in the
* unfragmentable part
* hdrtype - The first header type in the fragmentable part
*
* Returned Value:
* Unfragmentable Part length
*
****************************************************************************/
static uint16_t ipv6_fragout_getunfraginfo(FAR struct iob_s *iob,
uint16_t *hdroff,
uint16_t *hdrtype)
{
uint32_t iter = 0;
bool destopt = false;
uint16_t delta = sizeof(struct ipv6_hdr_s);
uint16_t unfraglen = delta;
uint8_t nxthdr;
FAR struct ipv6_hdr_s *ipv6;
FAR struct ipv6_extension_s *exthdr;
FAR uint8_t *payload;
ipv6 = (FAR struct ipv6_hdr_s *)(iob->io_data + iob->io_offset);
payload = (FAR uint8_t *)(ipv6 + 1);
exthdr = (FAR struct ipv6_extension_s *)payload;
nxthdr = ipv6->proto;
*hdroff = offsetof(struct ipv6_hdr_s, proto);
*hdrtype = ipv6->proto;
/* Traverse up to three extension headers, if the Destination Options
* Header appears repeatedly, ingore the secondary one and end the search.
* refer to rfc2460, section-4.1
*/
while (ipv6_exthdr(nxthdr) && iter++ < 3)
{
uint16_t extlen;
exthdr = (FAR struct ipv6_extension_s *)payload;
extlen = EXTHDR_LEN((unsigned int)exthdr->len);
switch (nxthdr)
{
case NEXT_DESTOPT_EH:
if (!destopt)
{
destopt = true;
}
else
{
/* This is the secondary Destination Options Header,
* end the search
*/
goto done;
}
case NEXT_ROUTING_EH:
case NEXT_HOPBYBOT_EH:
unfraglen = delta + extlen;
*hdroff = delta;
*hdrtype = exthdr->nxthdr;
}
payload += extlen;
delta += extlen;
nxthdr = exthdr->nxthdr;
}
done:
return unfraglen;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipv6_fragin
*
* Description:
* Handling incoming IPv6 fragment input, the input data
* (dev->d_iob) can be an I/O buffer chain
*
* Input Parameters:
* dev - The NIC device that the fragmented data comes from
*
* Returned Value:
* ENOMEM - No memory
* OK - The input fragment is processed as expected
*
****************************************************************************/
int32_t ipv6_fragin(FAR struct net_driver_s *dev)
{
FAR struct ip_fragsnode_s *node = NULL;
FAR struct ip_fraglink_s *fraginfo = NULL;
bool restartwdog;
if (dev->d_len != dev->d_iob->io_pktlen)
{
nerr("ERROR: Parameters error.\n");
return -EINVAL;
}
fraginfo = kmm_malloc(sizeof(struct ip_fraglink_s));
if (fraginfo == NULL)
{
nerr("ERROR: Failed to allocate buffer.\n");
return -ENOMEM;
}
/* Polulate fragment information from input packet data */
ipv6_fragin_getinfo(dev->d_iob, fraginfo);
nxmutex_lock(&g_ipfrag_lock);
/* Need to restart reassembly worker if the original linked list is empty */
restartwdog = ip_fragin_enqueue(dev, fraginfo);
node = fraginfo->fragsnode;
if (node->verifyflag & IP_FRAGVERIFY_RECVDALLFRAGS)
{
/* Well, all fragments of an IP frame have been received, remove
* node from link list first, then reassemble and dispatch to the
* stack.
*/
ip_frag_remnode(node);
/* All fragments belonging to one IP frame have been separated
* from the fragment processing module, unlocks mutex as soon
* as possible
*/
nxmutex_unlock(&g_ipfrag_lock);
/* Reassemble fragments to one IP frame and set the resulting
* IP frame to dev->d_iob
*/
ipv6_fragin_reassemble(node);
netdev_iob_replace(dev, node->outgoframe);
/* Free the memory of node */
kmm_free(node);
return ipv6_input(dev);
}
nxmutex_unlock(&g_ipfrag_lock);
if (restartwdog)
{
/* Restart the work queue for fragment processing */
ip_frag_startwdog();
}
return OK;
}
/****************************************************************************
* Name: ipv6_fragout
*
* Description:
* Execute the ipv6 fragment function. After this work is done, all
* fragments are maintained by dev->d_fragout. In order to reduce the
* cyclomatic complexity and facilitate maintenance, fragmentation is
* performed in two steps:
* 1. Reconstruct I/O Buffer according to MTU, which will reserve
* the space for the L3 header;
* 2. Fill the L3 header into the reserved space.
*
* Input Parameters:
* dev - The NIC device
* mtu - The MTU of current NIC
*
* Returned Value:
* 0 if success or a negative value if fail.
*
* Assumptions:
* Data length(dev->d_iob->io_pktlen) is grater than the MTU of
* current NIC
*
****************************************************************************/
int32_t ipv6_fragout(FAR struct net_driver_s *dev, uint16_t mtu)
{
uint16_t unfraglen;
uint16_t offset = 0;
uint32_t ipid;
uint32_t iter;
uint32_t nfrags;
uint16_t hdroff;
uint16_t hdrtype;
FAR struct iob_s *frag;
FAR struct ipv6_hdr_s *ref = NULL;
FAR struct ipv6_fragment_extension_s *fraghdr;
struct iob_queue_s fragq =
{
NULL, NULL
};
/* Get the length of Unfragmentable Part of the original ipv6 packet,
* Get the offset and value of nextheader filed in the last extension
* header of the unfragmentable part.
*/
unfraglen = ipv6_fragout_getunfraginfo(dev->d_iob, &hdroff, &hdrtype);
/* Reconstruct I/O Buffer according to MTU, which will reserve
* the space for the L3 header
*/
nfrags = ip_fragout_slice(dev->d_iob, PF_INET6, mtu, unfraglen, &fragq);
ASSERT(nfrags > 1);
netdev_iob_clear(dev);
ipid = ++g_ipv6id;
/* Fill the L3 header into the reserved space */
for (iter = 0; iter < nfrags; iter++)
{
frag = iob_remove_queue(&fragq);
if (iter == 0)
{
ref = (FAR struct ipv6_hdr_s *)(frag->io_data + frag->io_offset);
/* Update the IPv6 header for the zero fragment */
ipv6_fragout_buildipv6header(ref, ref, unfraglen,
frag->io_pktlen - IPv6_HDRLEN, hdroff, NEXT_FRAGMENT_EH);
/* Build the fragment header for the zero fragment */
fraghdr = (FAR struct ipv6_fragment_extension_s *)
(frag->io_data + frag->io_offset + unfraglen);
ipv6_fragout_buildipv6fragheader(fraghdr, hdrtype,
FRAGHDR_FRAG_MOREFRAGS, ipid);
}
else
{
uint16_t ipoff = offset - iter * (unfraglen + EXTHDR_FRAG_LEN);
if (iter < nfrags - 1)
{
ipoff |= FRAGHDR_FRAG_MOREFRAGS;
}
/* Refer to the zero fragment ipv6 header to construct the ipv6
* header of non-zero fragment
*/
ipv6_fragout_buildipv6header(ref,
(FAR struct ipv6_hdr_s *)(frag->io_data + frag->io_offset),
unfraglen, frag->io_pktlen - IPv6_HDRLEN, hdroff,
NEXT_FRAGMENT_EH);
/* Build extension fragment header for non-zero fragment */
fraghdr = (FAR struct ipv6_fragment_extension_s *)
(frag->io_data + frag->io_offset + unfraglen);
ipv6_fragout_buildipv6fragheader(fraghdr, hdrtype, ipoff, ipid);
}
/* Enqueue this fragment to dev->d_fragout */
if (iob_tryadd_queue(frag, &dev->d_fragout) < 0)
{
goto fail;
}
offset += frag->io_pktlen;
}
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.sent += nfrags - 1;
#endif
netdev_txnotify_dev(dev);
return OK;
fail:
netdev_iob_release(dev);
iob_free_chain(frag);
iob_free_queue(&fragq);
iob_free_queue(&dev->d_fragout);
--g_ipv6id;
return -ENOMEM;
}
#endif /* CONFIG_NET_IPv6 && CONFIG_NET_IPFRAG */
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