IPv6

The IPv6 library provides functions for creating and manipulation IPv6 packets.

Functionality

Create IPv6 packets of any length
Create and extract IPv6 headers including extension headers
Verify checksum of IPv6 packets

Other libraries in IPv6 are:

Example use

Include the libraries:

library nw_util;
context nw_util.nw_util_context;
library nw_ipv6;
context nw_ipv6.nw_ipv6_context;

Assume the variable v_payload contains the IPv6 payload, for example an UDP packet. The variables are defined:

variable v_header   : t_ipv6_header; -- header record
variable v_ipv6_pkt : t_slv_arr(0 to 1500)(7 downto 0); -- byte array
variable v_len      : natural;

First setup the header, then calculate the total IPv6 packet length before creating the packet.

v_header                   := C_DEFAULT_IPV6_HEADER; -- copy default header
v_header.src_addr          := f_ipv6_addr_2_slv_arr("2102:ec7::2"); -- change source address
v_len                      := f_ipv6_create_pkt_len(v_header, v_payload); -- calculate total packet length
v_ipv6_pkt(0 to v_len - 1) := f_ipv6_create_pkt(v_header, v_payload); -- create the packet

Extension headers are used by first defining a variable holding a list of extension headers, then adding individual extension headers to this list.

v_ext_header_list : t_ext_header_list := C_DEFAULT_EXT_HEADER_LIST; -- init the extension header list to empty

v_ext_header : t_extension_header; -- extension header to be added to list

Extension headers can added to the list in any order (note that RFC 2460 recommends a specific order).
Add Hop-by-Hop Options Header:

v_ext_header              := C_DEFAULT_EXT_HEADER; -- start with a default header
v_ext_header.header_type  := C_HOPOPT; -- Hop-by-Hop Options
v_ext_header.hdr_ext_len  := 1; -- 16byte total length
v_ext_header.data(0 to 1) := (x"01", x"0c"); -- PadN option
v_ext_header_list         := f_ipv6_add_ext_header(v_ext_header_list, v_ext_header); -- add header to list. Note that v_ext_header.next_header is updated here.

Add Routing Header:

v_ext_header               := C_DEFAULT_EXT_HEADER; -- start with a default header
v_ext_header.header_type   := C_IPV6_ROUTE; -- Routing Header
v_ext_header.routing_type  := x"00";  -- routing type 0
v_ext_header.segments_left := x"01";
v_ext_header.hdr_ext_len   := 1; -- 16byte total length
v_ext_header.data(0 to 7)  := f_ipv6_addr_2_slv_arr("4200:8a::44");
v_ext_header_list          := f_ipv6_add_ext_header(v_ext_header_list, v_ext_header); -- add header to list. 

Add Fragment Header:

v_ext_header                  := C_DEFAULT_EXT_HEADER; -- start with a default header
v_ext_header.header_type      := C_IPV6_FRAG; -- Fragment header
v_ext_header.framgment_offset := "0011001000000"; -- 13bit offset
v_ext_header.m_flag           := '0'; -- last fragment
v_ext_header.identification   := x"00000042"; 
v_ext_header.hdr_ext_len      := 0; -- 8byte total length
v_ext_header_list             := f_ipv6_add_ext_header(v_ext_header_list, v_ext_header); -- add header to list.

Add Destination Options Header:

v_ext_header              := C_DEFAULT_EXT_HEADER; -- start with a default header
v_ext_header.header_type  := C_IPV6_OPTS; -- Destination Options
v_ext_header.hdr_ext_len  := 0; -- 8byte total length
v_ext_header.data(0 to 3) := (x"01", x"02"); -- PadN option
v_ext_header_list         := f_ipv6_add_ext_header(v_ext_header_list, v_ext_header); -- add header to list.

Add Authentication Header (RFC 2402):

v_ext_header               := C_DEFAULT_EXT_HEADER; -- start with a default header
v_ext_header.header_type   := C_AH; -- Authentication Header
v_ext_header.hdr_ext_len   := 4; -- Note! Number of 4byte words minus 2
v_ext_header.spi           := x"12345678"; -- Security Parameters Index
v_ext_header.seq_no        := x"000000f4"; -- sequence number
v_ext_header.data(0 to 11) := f_gen_prbs(C_POLY_X16_X15_X13_X4_1, 8, 12); -- random payload
v_ext_header_list          := f_ipv6_add_ext_header(v_ext_header_list, v_ext_header); -- add header to list.

Finally create the IPv6 packet with extension headers:

v_len := f_ipv6_create_pkt_len(v_header, v_payload, v_ext_header_list); -- calculate total packet length

v_ipv6_pkt(0 to v_len - 1) := f_ipv6_create_pkt(v_header, v_payload, v_ext_header_list); -- create the packet

See further examples in the test bench nw_ipv6_tb.vhd.

Table of Contents

IPv6

Functionality

Example use