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@gamemann
gamemann / matrix.md
Last active August 2, 2023 22:06
Matrix Linux Command

Linux command that outputs code animations similar to the movie The Matrix.

while :; do \
    echo \
        $LINES \
        $COLUMNS \
        $(( $RANDOM % $COLUMNS)) \
        $(printf "\U$(($RANDOM % 500))"); \
 sleep 0.05; \
@gamemann
gamemann / ipv6_send.c
Created December 18, 2020 03:39
Small C program I made to send empty UDP packets per second over IPv6.
#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/if_ether.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>
@gamemann
gamemann / xdp_fw_ipv6_maps.c
Last active December 16, 2020 15:19
XDP FW trying to implement IPv6 support with BPF maps.
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/in.h>
#include <inttypes.h>
#include <stdint.h>
@gamemann
gamemann / xdp_fw_ipv6.c
Created December 16, 2020 15:06
XDP IPv6 support #1.
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/in.h>
#include <inttypes.h>
#include <stdint.h>
@gamemann
gamemann / xdp_bpf_maps.c
Created December 16, 2020 14:49
Small XDP program that stores IP and ICMP headers into a per-CPU map and prints out data later on. Not sure how well storing these in a per-CPU map will do in regards to performance.
#include <linux/bpf.h>
#include <linux/bpf_common.h>
#include <inttypes.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/in.h>
#include "/home/dev/XDP-Firewall/libbpf/src/bpf_helpers.h"
@gamemann
gamemann / udp_stress.c
Last active December 4, 2020 19:24
Program I made to get the most out of sending packets via Linux sockets. Was able to push 24 gbps at 61 bytes per packet with an older Intel Xeon.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysinfo.h>
#include <netinet/in.h>
#include <net/if.h>
#include <linux/if.h>
#include <linux/if_ether.h>
@gamemann
gamemann / xdp-payload-match.c
Last active May 8, 2020 13:47
Payload matching attempt via goto.
// Payload match.
if (filter[i]->payloadLen > 0)
{
// Initialize packet data.
for (uint16_t j = 0; j < MAX_PCKT_LENGTH; j++)
{
if ((j + 1) > filter[i]->payloadLen)
{
break;
}
@gamemann
gamemann / namespace.sh
Created April 25, 2020 01:38
Commands I ran to get NAT working on the endpoint machines for SRCDS servers. This allows Steam traffic to go out in IPIP form so the Master Server gets the correct IP. All other traffic is sent back to the forwarding server normally as long as the static route exists inside the network namespace.
#!/bin/bash
# Forwarding Server:
# IP - 10.50.0.3
# Do DNAT to game server machine.
iptables -t nat -A PREROUTING -d 10.50.0.3 -p udp --dport 27015 -j DNAT --to-destination 10.50.0.4
# Masquerade connections to game server machine (not sure if needed, can use SNAT rule as well if need to be).
iptables -t nat -A POSTROUTING -d 10.50.0.4 -j MASQUERADE
@gamemann
gamemann / test_veth.c
Created March 19, 2020 14:24
Testing sending outbound packets inside network namespace via AF_PACKET sockets
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <linux/if.h>
@gamemann
gamemann / TestServerv2.c
Created March 2, 2020 03:17
Altered version of TestServer.c.
/* Testing forwarding packets to destination. */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <linux/if_packet.h>