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nuttx/net/sixlowpan/sixlowpan_hc1.c

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/****************************************************************************
* net/sixlowpan/sixlowpan_hc1.c
*
* Copyright (C) 2017, Gregory Nutt, all rights reserved
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derives from Contiki:
*
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
* Authors: Adam Dunkels <adam@sics.se>
* Nicolas Tsiftes <nvt@sics.se>
* Niclas Finne <nfi@sics.se>
* Mathilde Durvy <mdurvy@cisco.com>
* Julien Abeille <jabeille@cisco.com>
* Joakim Eriksson <joakime@sics.se>
* Joel Hoglund <joel@sics.se>
*
* 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/net/netdev.h>
#include "sixlowpan/sixlowpan_internal.h"
#ifdef CONFIG_NET_6LOWPAN_COMPRESSION_HC1
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sixlowpan_compresshdr_hc1
*
* Description:
* Compress IP/UDP header using HC1 and HC_UDP
*
* This function is called by the 6lowpan code to create a compressed
* 6lowpan packet in the packetbuf buffer from a full IPv6 packet in the
* uip_buf buffer.
*
* If we can compress everything, we use HC1 dispatch, if not we use
* IPv6 dispatch. We can compress everything if:
*
* - IP version is
* - Flow label and traffic class are 0
* - Both src and dest ip addresses are link local
* - Both src and dest interface ID are recoverable from lower layer
* header
* - Next header is either ICMP, UDP or TCP
*
* Moreover, if next header is UDP, we try to compress it using HC_UDP.
* This is feasible is both ports are between F0B0 and F0B0 + 15\n\n
*
* Resulting header structure:
* - For ICMP, TCP, non compressed UDP\n
* HC1 encoding = 11111010 (UDP) 11111110 (TCP) 11111100 (ICMP)\n
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | LoWPAN HC1 Dsp | HC1 encoding | IPv6 Hop limit| L4 hdr + data|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | ...
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* - For compressed UDP
* HC1 encoding = 11111011, HC_UDP encoding = 11100000\n
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | LoWPAN HC1 Dsp| HC1 encoding | HC_UDP encod.| IPv6 Hop limit|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | src p.| dst p.| UDP checksum | L4 data...
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Input Parmeters:
* ieee - A reference to the IEE802.15.4 network device state
* ipv6 - The IPv6 header followd by TCP, UDP, or ICMPv6 header to be
* compressed
* destmac - L2 destination address, needed to compress the IP
* destination field
* fptr - Pointer to frame to be compressed.
*
* Returned Value:
* None
*
****************************************************************************/
void sixlowpan_compresshdr_hc1(FAR struct ieee802154_driver_s *ieee,
FAR const struct ipv6_hdr_s *ipv6,
FAR const struct sixlowpan_tagaddr_s *destmac,
FAR uint8_t *fptr)
{
FAR uint8_t *hc1 = fptr + g_frame_hdrlen;
/* Check if all the assumptions for full compression are valid */
if (ipv6->vtc != 0x60 || ipv6->tcf != 0 || ipv6->flow != 0 ||
!sixlowpan_islinklocal(ipv6->srcipaddr) ||
!sixlowpan_ismacbased(ipv6->srcipaddr, &ieee->i_dev.d_mac.ieee802154) ||
!sixlowpan_islinklocal(ipv6->destipaddr) ||
!sixlowpan_ismacbased(ipv6->destipaddr, destmac) ||
(ipv6->proto != IP_PROTO_ICMP6 && ipv6->proto != IP_PROTO_UDP &&
ipv6->proto != IP_PROTO_TCP))
{
/* IPV6 DISPATCH
* Something cannot be compressed, use IPV6 DISPATCH, compress
* nothing, copy IPv6 header into the frame buffer
*/
/* IPv6 dispatch header (1 byte) */
hc1[SIXLOWPAN_HC1_DISPATCH] = SIXLOWPAN_DISPATCH_IPV6;
g_frame_hdrlen += SIXLOWPAN_IPV6_HDR_LEN;
memcpy(fptr + g_frame_hdrlen, ipv6, IPv6_HDRLEN);
g_frame_hdrlen += IPv6_HDRLEN;
g_uncomp_hdrlen += IPv6_HDRLEN;
}
else
{
/* HC1 DISPATCH maximum compresssion:
* All fields in the IP header but Hop Limit are elided. If next
* header is UDP, we compress UDP header using HC2
*/
hc1[SIXLOWPAN_HC1_DISPATCH] = SIXLOWPAN_DISPATCH_HC1;
g_uncomp_hdrlen += IPv6_HDRLEN;
switch (ipv6->proto)
{
case IP_PROTO_ICMP6:
/* HC1 encoding and ttl */
hc1[SIXLOWPAN_HC1_ENCODING] = 0xfc;
hc1[SIXLOWPAN_HC1_TTL] = ipv6->ttl;
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
break;
#if CONFIG_NET_TCP
case IP_PROTO_TCP:
/* HC1 encoding and ttl */
hc1[SIXLOWPAN_HC1_ENCODING] = 0xfe;
hc1[SIXLOWPAN_HC1_TTL] = ipv6->ttl;
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
break;
#endif /* CONFIG_NET_TCP */
#if CONFIG_NET_UDP
case IP_PROTO_UDP:
{
FAR struct udp_hdr_s *udp =
&(((FAR struct ipv6udp_hdr_s *)ipv6)->udp);
/* Try to compress UDP header (we do only full compression).
* This is feasible if both src and dest ports are between
* CONFIG_NET_6LOWPAN_MINPORT and CONFIG_NET_6LOWPAN_MINPORT +
* 15
*/
ninfo("local/remote port %u/%u\n", udp->srcport, udp->destport);
if (ntohs(udp->srcport) >= CONFIG_NET_6LOWPAN_MINPORT &&
ntohs(udp->srcport) < (CONFIG_NET_6LOWPAN_MINPORT + 16) &&
ntohs(udp->destport) >= CONFIG_NET_6LOWPAN_MINPORT &&
ntohs(udp->destport) < (CONFIG_NET_6LOWPAN_MINPORT + 16))
{
FAR uint8_t *hcudp = fptr + g_frame_hdrlen;
/* HC1 encoding */
hcudp[SIXLOWPAN_HC1_HC_UDP_HC1_ENCODING] = 0xfb;
/* HC_UDP encoding, ttl, src and dest ports, checksum */
hcudp[SIXLOWPAN_HC1_HC_UDP_UDP_ENCODING] = 0xe0;
hcudp[SIXLOWPAN_HC1_HC_UDP_TTL] = ipv6->ttl;
hcudp[SIXLOWPAN_HC1_HC_UDP_PORTS] =
(uint8_t)((ntohs(udp->srcport) - CONFIG_NET_6LOWPAN_MINPORT) << 4) +
(uint8_t)((ntohs(udp->destport) - CONFIG_NET_6LOWPAN_MINPORT));
memcpy(&hcudp[SIXLOWPAN_HC1_HC_UDP_CHKSUM], &udp->udpchksum, 2);
g_frame_hdrlen += SIXLOWPAN_HC1_HC_UDP_HDR_LEN;
g_uncomp_hdrlen += UDP_HDRLEN;
}
else
{
/* HC1 encoding and ttl */
hc1[SIXLOWPAN_HC1_ENCODING] = 0xfa;
hc1[SIXLOWPAN_HC1_TTL] = ipv6->ttl;
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
}
}
break;
#endif /* CONFIG_NET_UDP */
}
}
}
/****************************************************************************
* Name: sixlowpan_uncompresshdr_hc1
*
* Description:
* Uncompress HC1 (and HC_UDP) headers and put them in sixlowpan_buf
*
* This function is called by the input function when the dispatch is
* HC1. It processes the frame in the IOB buffer, uncompresses the
* header fields, and copies the result in the packet buffer. At the
* end of the decompression, g_frame_hdrlen and uncompressed_hdr_len
* are set to the appropriate values
*
* Input Parameters:
* iplen - Equal to 0 if the packet is not a fragment (IP length is then
* inferred from the L2 length), non 0 if the packet is a 1st
* fragment.
* iob - Pointer to the IOB containing the received frame.
* fptr - Pointer to frame to be uncompressed.
* bptr - Output goes here. Normally this is a known offset into d_buf,
* may be redirected to a "bitbucket" on the case of FRAGN frames.
*
* Returned Value:
* Zero (OK) is returned on success, on failure a negater errno value is
* returned.
*
****************************************************************************/
int sixlowpan_uncompresshdr_hc1(uint16_t iplen, FAR struct iob_s *iob,
FAR uint8_t *fptr, FAR uint8_t *bptr)
{
FAR struct ipv6_hdr_s *ipv6 = (FAR struct ipv6_hdr_s *)bptr;
FAR uint8_t *hc1 = fptr + g_frame_hdrlen;
/* Format the IPv6 header in the device d_buf */
/* Set version, traffic clase, and flow label */
ipv6->vtc = 0x60; /* Bits 0-3: version, bits 4-7: traffic class (MS) */
ipv6->tcf = 0; /* Bits 0-3: traffic class (LS), 4-bits: flow label (MS) */
ipv6->flow = 0; /* 16-bit flow label (LS) */
g_uncomp_hdrlen += IPv6_HDRLEN;
/* len[], proto, and ttl depend on the encoding */
switch (hc1[SIXLOWPAN_HC1_ENCODING] & 0x06)
{
case SIXLOWPAN_HC1_NH_ICMP6:
ipv6->proto = IP_PROTO_ICMP6;
ipv6->ttl = hc1[SIXLOWPAN_HC1_TTL];
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
break;
#if CONFIG_NET_TCP
case SIXLOWPAN_HC1_NH_TCP:
ipv6->proto = IP_PROTO_TCP;
ipv6->ttl = hc1[SIXLOWPAN_HC1_TTL];
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
break;
#endif /* CONFIG_NET_TCP */
#if CONFIG_NET_UDP
case SIXLOWPAN_HC1_NH_UDP:
{
FAR struct udp_hdr_s *udp = (FAR struct udp_hdr_s *)(bptr + IPv6_HDRLEN);
FAR uint8_t *hcudp = fptr + g_frame_hdrlen;
ipv6->proto = IP_PROTO_UDP;
if ((hcudp[SIXLOWPAN_HC1_HC_UDP_HC1_ENCODING] & 0x01) != 0)
{
/* UDP header is compressed with HC_UDP */
if (hcudp[SIXLOWPAN_HC1_HC_UDP_UDP_ENCODING] !=
SIXLOWPAN_HC_UDP_ALL_C)
{
nwarn("WARNING: sixlowpan (uncompress_hdr), packet not supported");
return -EOPNOTSUPP;
}
/* IP TTL */
ipv6->ttl = hcudp[SIXLOWPAN_HC1_HC_UDP_TTL];
/* UDP ports, len, checksum */
udp->srcport =
htons(CONFIG_NET_6LOWPAN_MINPORT + (hcudp[SIXLOWPAN_HC1_HC_UDP_PORTS] >> 4));
udp->destport =
htons(CONFIG_NET_6LOWPAN_MINPORT + (hcudp[SIXLOWPAN_HC1_HC_UDP_PORTS] & 0x0F));
memcpy(&udp->udpchksum, &hcudp[SIXLOWPAN_HC1_HC_UDP_CHKSUM], 2);
g_uncomp_hdrlen += UDP_HDRLEN;
g_frame_hdrlen += SIXLOWPAN_HC1_HC_UDP_HDR_LEN;
}
else
{
g_frame_hdrlen += SIXLOWPAN_HC1_HDR_LEN;
}
}
break;
#endif /* CONFIG_NET_UDP */
default:
return -EPROTONOSUPPORT;
}
/* IP length field. */
if (iplen == 0)
{
/* This is not a fragmented packet */
ipv6->len[0] = 0;
ipv6->len[1] = iob->io_len - g_frame_hdrlen + g_uncomp_hdrlen -
IPv6_HDRLEN;
}
else
{
/* This is a 1st fragment */
ipv6->len[0] = (iplen - IPv6_HDRLEN) >> 8;
ipv6->len[1] = (iplen - IPv6_HDRLEN) & 0x00FF;
}
#if CONFIG_NET_UDP
/* Length field in UDP header */
if (ipv6->proto == IP_PROTO_UDP)
{
FAR struct udp_hdr_s *udp = (FAR struct udp_hdr_s *)(bptr + IPv6_HDRLEN);
memcpy(&udp->udplen, &ipv6->len[0], 2);
}
#endif
return OK;
}
#endif /* CONFIG_NET_6LOWPAN_COMPRESSION_HC1 */
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