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gnrc_sixlowpan_iphc: add extension header decoding

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This commit is contained in:
Martine S. Lenders 2019-12-05 11:39:56 +01:00
parent 3bf426e6fc
commit 0b3f785dfe
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GPG Key ID: CCD317364F63286F
2 changed files with 240 additions and 16 deletions
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48
sys/net/gnrc/network_layer/ipv6/ext/gnrc_ipv6_ext.c
View File

@ -25,6 +25,11 @@
#include "net/gnrc/ipv6.h"
#include "net/gnrc/ipv6/ext/frag.h"
#include "net/gnrc/ipv6/ext/rh.h"
#if defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) && \
defined(MODULE_GNRC_IPV6_EXT_FRAG)
#include "net/udp.h"
#endif /* defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) &&
* defined(MODULE_GNRC_IPV6_EXT_FRAG) */
#include "net/gnrc/ipv6/ext.h"
@ -101,7 +106,22 @@ gnrc_pktsnip_t *gnrc_ipv6_ext_process_all(gnrc_pktsnip_t *pkt,
uint8_t *protnum)
{
bool is_ext = true;
#if defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) && \
defined(MODULE_GNRC_IPV6_EXT_FRAG)
bool is_frag = false;
#endif /* defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) &&
* defined(MODULE_GNRC_IPV6_EXT_FRAG) */
while (is_ext) {
#if defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) && \
defined(MODULE_GNRC_IPV6_EXT_FRAG)
if (*protnum == PROTNUM_IPV6_EXT_FRAG) {
/* just assigning the if expression might override it if
* fragment header is not the last extension header ;-) */
is_frag = true;
}
#endif /* defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) &&
* defined(MODULE_GNRC_IPV6_EXT_FRAG) */
switch (*protnum) {
case PROTNUM_IPV6_EXT_DST:
case PROTNUM_IPV6_EXT_RH:
@ -127,6 +147,34 @@ gnrc_pktsnip_t *gnrc_ipv6_ext_process_all(gnrc_pktsnip_t *pkt,
}
break;
}
#if defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) && \
defined(MODULE_GNRC_IPV6_EXT_FRAG)
case PROTNUM_UDP:
if (is_frag) {
DEBUG("gnrc_ipv6_ext: adapting compressed header length\n");
/* we can only really now determine the length of the UDP
* packet, after the IPv6 datagram is fully reassembled */
udp_hdr_t *udp_hdr = pkt->data;
udp_hdr->length = byteorder_htons((uint16_t)pkt->size);
}
is_ext = false;
break;
case PROTNUM_IPV6:
if (is_frag) {
DEBUG("gnrc_ipv6_ext: adapting compressed header length\n");
/* we can only really now determine the length of the
* encapsulated IPv6 header, after the IPv6 datagram is
* fully reassembled */
ipv6_hdr_t *ipv6_hdr = pkt->data;
ipv6_hdr->len = byteorder_htons((uint16_t)pkt->size -
sizeof(ipv6_hdr_t));
}
is_ext = false;
break;
#endif /* defined(MODULE_GNRC_SIXLOWPAN_IPHC_NHC) &&
* defined(MODULE_GNRC_IPV6_EXT_FRAG) */
default:
is_ext = false;
break;

208
sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c
View File

@ -98,6 +98,8 @@
#define NHC_UDP_8BIT_MASK (0xFF00)
#define NHC_IPV6_EXT_ID (0xE0)
#define NHC_IPV6_EXT_ID_ALT (0xE8) /* first bit of EID 1 */
#define NHC_IPV6_EXT_EID_MASK (0x0E)
#define NHC_IPV6_EXT_NH (0x01)
#define NHC_IPV6_EXT_EID_HOPOPT (0x00 << 1)
@ -429,6 +431,151 @@ static size_t _iphc_ipv6_decode(const uint8_t *iphc_hdr,
}
#ifdef MODULE_GNRC_SIXLOWPAN_IPHC_NHC
static size_t _iphc_nhc_ipv6_ext_decode(gnrc_pktsnip_t *sixlo, size_t offset,
size_t *prev_nh_offset,
gnrc_pktsnip_t *ipv6,
size_t *uncomp_hdr_len)
{
uint8_t *payload = sixlo->data;
ipv6_ext_t *ext_hdr;
uint8_t ipv6_ext_nhc = payload[offset++];
uint8_t protnum;
uint8_t ext_len = (ipv6_ext_nhc & NHC_IPV6_EXT_NH)
? payload[offset]
: payload[offset + 1];
/* realloc size for uncompressed snip, if too small */
if (ipv6->size < (*uncomp_hdr_len + sizeof(ipv6_ext_t) + ext_len)) {
if (gnrc_pktbuf_realloc_data(ipv6,
*uncomp_hdr_len + sizeof(ipv6_ext_t) +
ext_len)) {
DEBUG("6lo iphc: unable to decode IPv6 Extension header NHC "
"(not enough buffer space)\n");
return 0;
}
}
ext_hdr = (ipv6_ext_t *)((uint8_t *)ipv6->data + *uncomp_hdr_len);
switch (ipv6_ext_nhc & NHC_IPV6_EXT_EID_MASK) {
case NHC_IPV6_EXT_EID_HOPOPT:
protnum = PROTNUM_IPV6_EXT_HOPOPT;
break;
case NHC_IPV6_EXT_EID_RH:
protnum = PROTNUM_IPV6_EXT_RH;
break;
case NHC_IPV6_EXT_EID_FRAG:
protnum = PROTNUM_IPV6_EXT_FRAG;
break;
case NHC_IPV6_EXT_EID_DST:
protnum = PROTNUM_IPV6_EXT_DST;
break;
case NHC_IPV6_EXT_EID_MOB:
protnum = PROTNUM_IPV6_EXT_MOB;
break;
default:
DEBUG("6lo iphc: unexpected extension header EID %u\n",
(ipv6_ext_nhc & NHC_IPV6_EXT_EID_MASK) >> 1U);
return 0;
}
((uint8_t *)ipv6->data)[*prev_nh_offset] = protnum;
if (!(ipv6_ext_nhc & NHC_IPV6_EXT_NH)) {
ext_hdr->nh = payload[offset++];
/* signal end of next header compression to caller */
*prev_nh_offset = 0;
}
else {
*prev_nh_offset = (&ext_hdr->nh) - ((uint8_t *)ipv6->data);
}
/* skip already fetched length field */
offset++;
ext_hdr->len = ((sizeof(ipv6_ext_t) + ext_len) - IPV6_EXT_LEN_UNIT) /
IPV6_EXT_LEN_UNIT;
memcpy(ext_hdr + 1, &payload[offset], ext_len);
offset += ext_len;
*uncomp_hdr_len += sizeof(ipv6_ext_t) + ext_len;
return offset;
}
static size_t _iphc_nhc_ipv6_decode(gnrc_pktsnip_t *sixlo, size_t offset,
const gnrc_sixlowpan_frag_rb_t *rbuf,
size_t *prev_nh_offset,
gnrc_pktsnip_t *ipv6,
size_t *uncomp_hdr_len)
{
uint8_t *payload = sixlo->data;
uint8_t ipv6_nhc = payload[offset];
switch (ipv6_nhc & NHC_IPV6_EXT_EID_MASK) {
case NHC_IPV6_EXT_EID_HOPOPT:
case NHC_IPV6_EXT_EID_RH:
case NHC_IPV6_EXT_EID_FRAG:
case NHC_IPV6_EXT_EID_DST:
case NHC_IPV6_EXT_EID_MOB: {
size_t tmp;
tmp = _iphc_nhc_ipv6_ext_decode(sixlo, offset, prev_nh_offset,
ipv6, uncomp_hdr_len);
if (tmp == 0) {
/* unable to parse IPHC header */
return 0;
}
offset = tmp;
break;
}
case NHC_IPV6_EXT_EID_IPV6: {
gnrc_pktsnip_t *netif = gnrc_pktsnip_search_type(sixlo,
GNRC_NETTYPE_NETIF);
ipv6_hdr_t *ipv6_hdr;
uint16_t payload_len;
size_t tmp;
offset++; /* move over NHC header */
/* realloc size for uncompressed snip, if too small */
if (ipv6->size < (*uncomp_hdr_len + sizeof(ipv6_hdr_t))) {
if (gnrc_pktbuf_realloc_data(ipv6,
*uncomp_hdr_len +
sizeof(ipv6_hdr_t))) {
DEBUG("6lo iphc: unable to decode IPv6 encapsulated header "
"NHC (not enough buffer space)\n");
return 0;
}
}
ipv6_hdr = (ipv6_hdr_t *)(((uint8_t *)ipv6->data) + *uncomp_hdr_len);
tmp = _iphc_ipv6_decode(&payload[offset], netif->data,
gnrc_netif_hdr_get_netif(netif->data),
ipv6_hdr);
if (tmp == 0) {
/* unable to parse IPHC header */
return 0;
}
((uint8_t *)ipv6->data)[*prev_nh_offset] = PROTNUM_IPV6;
if (payload[offset + IPHC1_IDX] & SIXLOWPAN_IPHC1_NH) {
*prev_nh_offset = (&ipv6_hdr->nh) - ((uint8_t *)ipv6->data);
}
else {
/* signal end of next header compression to caller */
*prev_nh_offset = 0;
}
offset += tmp;
/* might be needed to be overwritten by IPv6 reassembly after the IPv6
* packet was reassembled to get complete length */
if (rbuf != NULL) {
payload_len = rbuf->super.datagram_size - *uncomp_hdr_len-
sizeof(ipv6_hdr_t);
}
else {
payload_len = (sixlo->size + *uncomp_hdr_len) -
sizeof(ipv6_hdr_t) - offset;
}
ipv6_hdr->len = byteorder_htons(payload_len);
*uncomp_hdr_len += sizeof(ipv6_hdr_t);
break;
}
default:
DEBUG("6lo iphc: unknown IPv6 extension header EID\n");
break;
}
return offset;
}
/**
* @brief Decodes UDP NHC
*
@ -437,6 +584,8 @@ static size_t _iphc_ipv6_decode(const uint8_t *iphc_hdr,
* @param[in] rbuf Reassembly buffer entry if @p ipv6 is a
* fragmented datagram. May be NULL, if @p ipv6
* is not fragmented
* @param[out] prev_nh_offset Offset to previous nh field in
* gnrc_pktsnip_t::data of @p ipv6
* @param[out] ipv6 The packet to write the decoded data to
* @param[in,out] uncomp_hdr_len Number of bytes already decoded into @p ipv6
* by IPHC and other NHC. Adds size of @ref
@ -448,10 +597,10 @@ static size_t _iphc_ipv6_decode(const uint8_t *iphc_hdr,
*/
static size_t _iphc_nhc_udp_decode(gnrc_pktsnip_t *sixlo, size_t offset,
const gnrc_sixlowpan_frag_rb_t *rbuf,
gnrc_pktsnip_t *ipv6, size_t *uncomp_hdr_len)
size_t prev_nh_offset, gnrc_pktsnip_t *ipv6,
size_t *uncomp_hdr_len)
{
uint8_t *payload = sixlo->data;
ipv6_hdr_t *ipv6_hdr;
udp_hdr_t *udp_hdr;
uint16_t payload_len;
uint8_t udp_nhc = payload[offset++];
@ -465,7 +614,6 @@ static size_t _iphc_nhc_udp_decode(gnrc_pktsnip_t *sixlo, size_t offset,
return 0;
}
}
ipv6_hdr = ipv6->data;
udp_hdr = (udp_hdr_t *)((uint8_t *)ipv6->data + *uncomp_hdr_len);
network_uint16_t *src_port = &(udp_hdr->src_port);
network_uint16_t *dst_port = &(udp_hdr->dst_port);
@ -524,7 +672,7 @@ static size_t _iphc_nhc_udp_decode(gnrc_pktsnip_t *sixlo, size_t offset,
}
udp_hdr->length = byteorder_htons(payload_len);
*uncomp_hdr_len += sizeof(udp_hdr_t);
ipv6_hdr->nh = PROTNUM_UDP;
((uint8_t *)ipv6->data)[prev_nh_offset] = PROTNUM_UDP;
return offset;
}
@ -582,19 +730,47 @@ void gnrc_sixlowpan_iphc_recv(gnrc_pktsnip_t *sixlo, void *rbuf_ptr,
}
#ifdef MODULE_GNRC_SIXLOWPAN_IPHC_NHC
if (iphc_hdr[IPHC1_IDX] & SIXLOWPAN_IPHC1_NH) {
switch (iphc_hdr[payload_offset] & NHC_ID_MASK) {
case NHC_UDP_ID: {
payload_offset = _iphc_nhc_udp_decode(sixlo, payload_offset,
rbuf, ipv6,
&uncomp_hdr_len);
if (payload_offset == 0) {
_recv_error_release(sixlo, ipv6, rbuf);
return;
bool nhc_header = true;
ipv6_hdr = ipv6->data;
size_t prev_nh_offset = (&ipv6_hdr->nh) - ((uint8_t *)ipv6->data);
while (nhc_header) {
switch (iphc_hdr[payload_offset] & NHC_ID_MASK) {
case NHC_IPV6_EXT_ID:
case NHC_IPV6_EXT_ID_ALT:
payload_offset = _iphc_nhc_ipv6_decode(sixlo,
payload_offset,
rbuf,
&prev_nh_offset,
ipv6,
&uncomp_hdr_len);
if (payload_offset == 0) {
_recv_error_release(sixlo, ipv6, rbuf);
return;
}
/* prev_nh_offset is set to 0 if next header is not
* compressed (== NH flag in compression header not set) */
nhc_header = (prev_nh_offset > 0);
break;
case NHC_UDP_ID: {
payload_offset = _iphc_nhc_udp_decode(sixlo,
payload_offset,
rbuf,
prev_nh_offset,
ipv6,
&uncomp_hdr_len);
if (payload_offset == 0) {
_recv_error_release(sixlo, ipv6, rbuf);
return;
}
/* no NHC after UDP header */
nhc_header = false;
break;
}
break;
default:
nhc_header = false;
break;
}
default:
break;
}
}
#endif
@ -649,7 +825,7 @@ void gnrc_sixlowpan_iphc_recv(gnrc_pktsnip_t *sixlo, void *rbuf_ptr,
_recv_error_release(sixlo, ipv6, rbuf);
return;
}
/* assign IPv6 header only here in case realloc changed the address */
/* re-assign IPv6 header in case realloc changed the address */
ipv6_hdr = ipv6->data;
ipv6_hdr->len = byteorder_htons(payload_len);
memcpy(((uint8_t *)ipv6->data) + uncomp_hdr_len,