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Merge pull request #2499 from gebart/pr/lowpan-address-decoding-fixes
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sixlowpan: Handle 16-bit addresses correctly (both decode and encode)
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@OlegHahm
OlegHahm committed Apr 1, 2015
2 parents cbdd262 + 334aeca commit 26710c1
Showing 1 changed file with 72 additions and 68 deletions.
140 changes: 72 additions & 68 deletions sys/net/network_layer/sixlowpan/lowpan.c
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Expand Up @@ -874,7 +874,7 @@ void lowpan_read(uint8_t *data, uint8_t length, net_if_eui64_t *s_addr,

}

/* draft-ietf-6lowpan-hc-13#section-3.1 */
/* RFC6282 https://tools.ietf.org/html/rfc6282#section-3.1 */
uint8_t lowpan_iphc_encoding(int if_id, const uint8_t *dest, int dest_len,
ipv6_hdr_t *ipv6_buf_extra, uint8_t *ptr)
{
Expand Down Expand Up @@ -1011,12 +1011,11 @@ uint8_t lowpan_iphc_encoding(int if_id, const uint8_t *dest, int dest_len,
* and possibly the link-layer addresses.*/
lowpan_iphc[1] |= 0x30;
}
else if ((ipv6_buf->srcaddr.uint16[4] == 0) &&
(ipv6_buf->srcaddr.uint16[5] == 0) &&
(ipv6_buf->srcaddr.uint16[6] == 0) &&
((ipv6_buf->srcaddr.uint8[14]) & 0x80) == 0) {
/* 49-bit of interface identifier are 0, so we can compress
* source address-iid to 16-bit */
else if ((ipv6_buf->srcaddr.uint32[2] == HTONL(0x000000ffu)) &&
(ipv6_buf->srcaddr.uint16[6] == HTONL(0xfe00u))) {
/* The 48 leading bits of the interface identifier are
* 0000:00FF:FE00, so we can compress the source address-iid to
* 16-bit */
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->srcaddr.uint16[7], 2);
hdr_pos += 2;
/* 16 bits. The address is derived using context information
Expand All @@ -1043,48 +1042,46 @@ uint8_t lowpan_iphc_encoding(int if_id, const uint8_t *dest, int dest_len,
/* 1: Destination address is a multicast address. */
lowpan_iphc[1] |= SIXLOWPAN_IPHC2_M;

/* just another cool if condition */
if ((ipv6_buf->destaddr.uint8[1] == 2) &&
(ipv6_buf->destaddr.uint16[1] == 0) &&
(ipv6_buf->destaddr.uint16[2] == 0) &&
(ipv6_buf->destaddr.uint16[3] == 0) &&
(ipv6_buf->destaddr.uint16[4] == 0) &&
(ipv6_buf->destaddr.uint16[5] == 0) &&
(ipv6_buf->destaddr.uint16[6] == 0) &&
(ipv6_buf->destaddr.uint8[14] == 0)) {
/* 11: 8 bits. The address takes the form FF02::00XX. */
lowpan_iphc[1] |= 0x03;
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[15];
hdr_pos++;
}
else if ((ipv6_buf->destaddr.uint16[1] == 0) &&
(ipv6_buf->destaddr.uint16[2] == 0) &&
(ipv6_buf->destaddr.uint16[3] == 0) &&
(ipv6_buf->destaddr.uint16[4] == 0) &&
(ipv6_buf->destaddr.uint16[5] == 0) &&
(ipv6_buf->destaddr.uint8[12] == 0)) {
/* 10: 32 bits. The address takes the form FFXX::00XX:XXXX. */
lowpan_iphc[1] |= 0x02;
/* copy second and last 3 byte */
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[1];
hdr_pos++;
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint8[13], 3);
hdr_pos += 3;
}
else if ((ipv6_buf->destaddr.uint16[1] == 0) &&
(ipv6_buf->destaddr.uint16[2] == 0) &&
(ipv6_buf->destaddr.uint16[3] == 0) &&
(ipv6_buf->destaddr.uint16[4] == 0) &&
(ipv6_buf->destaddr.uint8[10] == 0)) {
/* 01: 48 bits. The address takes the form FFXX::00XX:XXXX:XXXX */
lowpan_iphc[1] |= 0x01;
/* copy second and last 5 byte */
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[1];
hdr_pos++;
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint8[11], 5);
hdr_pos += 5;
/* Check if we can compress any part of the address */
if ((ipv6_buf->destaddr.uint8[0] == 0xff) &&
(ipv6_buf->destaddr.uint16[1] == HTONS(0x0000u)) &&
(ipv6_buf->destaddr.uint32[1] == HTONL(0x00000000u)) &&
(ipv6_buf->destaddr.uint16[4] == HTONS(0x0000u)) &&
(ipv6_buf->destaddr.uint8[10] == 0x00)) {
/* If we got here then the address is on the form:
* FFXX:0000:0000:0000:0000:00XX:XXXX:XXXX
* which means that it can be compressed. */
if ((ipv6_buf->destaddr.uint8[1] == 0x02) &&
(ipv6_buf->destaddr.uint16[5] == HTONS(0x0000u)) &&
(ipv6_buf->destaddr.uint16[6] == HTONS(0x0000u)) &&
(ipv6_buf->destaddr.uint8[14] == 0x00)) {
/* 11: 8 bits. The address takes the form FF02::00XX. */
lowpan_iphc[1] |= 0x03;
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[15];
hdr_pos++;
}
else if ((ipv6_buf->destaddr.uint16[5] == HTONS(0x0000u)) &&
(ipv6_buf->destaddr.uint8[12] == 0x00)) {
/* 10: 32 bits. The address takes the form FFXX::00XX:XXXX. */
lowpan_iphc[1] |= 0x02;
/* copy second and last 3 bytes */
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[1];
hdr_pos++;
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint8[13], 3);
hdr_pos += 3;
}
else {
/* 01: 48 bits. The address takes the form FFXX::00XX:XXXX:XXXX */
lowpan_iphc[1] |= 0x01;
/* copy second and last 5 byte */
ipv6_hdr_fields[hdr_pos] = ipv6_buf->destaddr.uint8[1];
hdr_pos++;
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint8[11], 5);
hdr_pos += 5;
}
}
else {
/* Full 128 bit address */
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint8[0], 16);
hdr_pos += 16;
}
Expand All @@ -1107,25 +1104,24 @@ uint8_t lowpan_iphc_encoding(int if_id, const uint8_t *dest, int dest_len,
* and possibly the link-layer addresses.*/
lowpan_iphc[1] |= 0x03;
}
else if (dest_len == 2 &&
ipv6_buf->destaddr.uint32[2] == HTONL(0x000000ff) &&
ipv6_buf->destaddr.uint16[6] == HTONS(0xfe00) &&
ipv6_buf->destaddr.uint16[7] == *((uint16_t *) dest)) {
/* 0 bits. The address is derived using context information
* and possibly the link-layer addresses.*/
lowpan_iphc[1] |= 0x03;
}
else if ((ipv6_buf->destaddr.uint16[4] == 0) &&
(ipv6_buf->destaddr.uint16[5] == 0) &&
(ipv6_buf->destaddr.uint16[6] == 0) &&
((ipv6_buf->destaddr.uint8[14]) & 0x80) == 0) {
/* 49-bit of interface identifier are 0, so we can compress
* source address-iid to 16-bit */
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint16[7], 2);
hdr_pos += 2;
/* 16 bits. The address is derived using context information
* and the 16 bits carried inline. */
lowpan_iphc[1] |= 0x02;
else if (ipv6_buf->destaddr.uint32[2] == HTONL(0x000000ff) &&
ipv6_buf->destaddr.uint16[6] == HTONS(0xfe00)) {
if (dest_len == 2 &&
ipv6_buf->destaddr.uint16[7] == *((uint16_t *) dest)) {
/* 0 bits. The address is derived using context information
* and possibly the link-layer addresses.*/
lowpan_iphc[1] |= 0x03;
}
else {
/* The 48 leading bits of the interface identifier are
* 0000:00FF:FE00, so we can compress the source address-iid to
* 16-bit */
memcpy(&ipv6_hdr_fields[hdr_pos], &ipv6_buf->destaddr.uint16[7], 2);
hdr_pos += 2;
/* 16 bits. The address is derived using context information
* and the 16 bits carried inline. */
lowpan_iphc[1] |= 0x02;
}
}
else {
memcpy(&ipv6_hdr_fields[hdr_pos], &(ipv6_buf->destaddr.uint16[4]), 8);
Expand All @@ -1136,6 +1132,7 @@ uint8_t lowpan_iphc_encoding(int if_id, const uint8_t *dest, int dest_len,
}
}
else {
/* Full 128 bit address */
memcpy(&ipv6_hdr_fields[hdr_pos], &(ipv6_buf->destaddr.uint8[0]), 16);
hdr_pos += 16;
}
Expand Down Expand Up @@ -1268,6 +1265,7 @@ void lowpan_iphc_decoding(uint8_t *data, uint8_t length, net_if_eui64_t *s_addr,
/* Generate IPv6 address from stateless information, if SAC=1 we will use
* this stateless information as a starting point for the stateful
* information. */
/* RFC 6282 describes each of the following address compression methods */
switch (((lowpan_iphc[1] & SIXLOWPAN_IPHC2_SAM) >> 4) & 0x03) {
case (0x01): {
/* 64-bits */
Expand All @@ -1281,7 +1279,10 @@ void lowpan_iphc_decoding(uint8_t *data, uint8_t length, net_if_eui64_t *s_addr,
case (0x02): {
/* 16-bits */
memcpy(&(ipv6_buf->srcaddr.uint8[0]), &ll_prefix[0], 2);
memset(&(ipv6_buf->srcaddr.uint8[2]), 0, 12);
ipv6_buf->srcaddr.uint16[1] = HTONS(0x0000u);
ipv6_buf->srcaddr.uint32[1] = HTONL(0x00000000u);
ipv6_buf->srcaddr.uint32[2] = HTONL(0x000000ffu);
ipv6_buf->srcaddr.uint16[6] = HTONS(0xfe00u);
memcpy(&(ipv6_buf->srcaddr.uint8[14]), &ipv6_hdr_fields[hdr_pos], 2);
hdr_pos += 2;
break;
Expand Down Expand Up @@ -1415,7 +1416,10 @@ void lowpan_iphc_decoding(uint8_t *data, uint8_t length, net_if_eui64_t *s_addr,
case (0x02): {
/* 16-bits */
memcpy(&(ipv6_buf->destaddr.uint8[0]), &ll_prefix[0], 2);
memset(&(ipv6_buf->destaddr.uint8[2]), 0, 12);
ipv6_buf->destaddr.uint16[1] = HTONS(0x0000u);
ipv6_buf->destaddr.uint32[1] = HTONL(0x00000000u);
ipv6_buf->destaddr.uint32[2] = HTONL(0x000000ffu);
ipv6_buf->destaddr.uint16[6] = HTONS(0xfe00u);
memcpy(&(ipv6_buf->destaddr.uint8[14]), &ipv6_hdr_fields[hdr_pos], 2);
hdr_pos += 2;
break;
Expand Down

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