diff options
| author | grothoff <grothoff@140774ce-b5e7-0310-ab8b-a85725594a96> | 2012-01-17 19:39:52 +0000 |
|---|---|---|
| committer | grothoff <grothoff@140774ce-b5e7-0310-ab8b-a85725594a96> | 2012-01-17 19:39:52 +0000 |
| commit | bf8b298c753f2dcd202939380b58aedf2b0fc05b (patch) | |
| tree | 7de9ae93ccde2ec4ccaf11b590d9ec5c339e26a6 /src/tun | |
| parent | 54b312343894bbd7ad76e9b0498f0782d72287b4 (diff) | |
-move IPv6-TCP checksum calculation to tun library
git-svn-id: https://gnunet.org/svn/gnunet@19216 140774ce-b5e7-0310-ab8b-a85725594a96
Diffstat (limited to 'src/tun')
| -rw-r--r-- | src/tun/tun.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/tun/tun.c b/src/tun/tun.c index 005c7013dd..c30861cce8 100644 --- a/src/tun/tun.c +++ b/src/tun/tun.c @@ -95,5 +95,37 @@ GNUNET_TUN_initialize_ipv6_header (struct GNUNET_TUN_IPv6Header *ip, } +/** + * Calculate IPv6 TCP checksum. + * + * @param ipv6 header fully initialized + * @param tcp header (initialized except for CRC) + * @param payload the TCP payload + * @param payload_length number of bytes of TCP payload + */ +void +GNUNET_TUN_calculate_tcp6_checksum (const struct GNUNET_TUN_IPv6Header *ip, + struct GNUNET_TUN_TcpHeader *tcp, + const void *payload, + uint16_t payload_length) +{ + uint32_t sum; + uint32_t tmp; + + GNUNET_assert (payload_length + sizeof (struct GNUNET_TUN_IPv6Header) + sizeof (struct GNUNET_TUN_TcpHeader) == + ntohs (ip->payload_length)); + tcp->crc = 0; + sum = GNUNET_CRYPTO_crc16_step (0, &ip->source_address, 2 * sizeof (struct in6_addr)); + tmp = htonl (sizeof (struct GNUNET_TUN_TcpHeader) + payload_length); + sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); + tmp = htonl (IPPROTO_TCP); + sum = GNUNET_CRYPTO_crc16_step (sum, &tmp, sizeof (uint32_t)); + sum = GNUNET_CRYPTO_crc16_step (sum, tcp, + sizeof (struct GNUNET_TUN_TcpHeader)); + sum = GNUNET_CRYPTO_crc16_step (sum, payload, payload_length); + tcp->crc = GNUNET_CRYPTO_crc16_finish (sum); +} + + /* end of tun.c */ |