ICMP for IPv4

The ICMPv4 library provides functions for creating and manipulation ICMP packets.

Functionality

Create ICMP packets of any length
Create and extract ICMP headers
Verify checksum of ICMP packets

Example use

Include the libraries:

library nw_util;
context nw_util.nw_util_context;
library nw_ipv4;
context nw_ipv4.nw_ipv4_context;

Assume the variable v_payload contains the ICMP payload. The variables are defined:

variable v_header   : t_icmpv4_header; -- ICMP header record
variable v_payload  : t_slv_arr(0 to 31)(7 downto 0);
variable v_icmp_pkt : t_slv_arr(0 to 39)(7 downto 0); -- byte array
variable v_len      : natural;

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

v_header                   := C_DEFAULT_ICMPV4_HEADER; -- copy default header (ping request)
v_payload                  := f_gen_nrs(x"80", 32); -- payload contents
v_len                      := f_icmpv4_create_pkt_len(v_header, v_payload); -- calculate total packet length
v_icmp_pkt(0 to v_len - 1) := f_icmpv4_create_pkt(v_header, v_payload); -- create the packet (no checksum)

The variable v_icmp_pkt is an 8-bit array. This can of course be rearranged to any word width with f_repack().

v_icmpv4_pkt_32 := f_repack(v_icmp_pkt, 32, C_MSB_FIRST); -- repack to 32bit words (padded with zeros if required)

See further examples in the test bench nw_ipv4_tb.vhd.

Table of Contents

ICMP for IPv4

Functionality

Example use