DRiKE

static __always_inline
void csum_remove_data(uint32_t *csum, struct cursor *c, uint16_t len)
{
    if (c->pos + len <= c->end) {
        *csum = bpf_csum_diff(c->pos, len, 0, 0, *csum);
        c->pos += len;
    }
}

int xdp_dns_says_no(struct xdp_md *ctx)

DRiKE

 // continuing:

    if (dns->arcount) {
        struct dns_rr  *opt_rr;
        uint8_t        *opt_owner = c->pos;
 
        opt_owner = c->pos;
        if (++c->pos > c->end || *opt_owner
        || !(opt_rr = parse_dns_rr(c))
        ||   opt_rr->type != __bpf_htons(RR_TYPE_OPT))

DRiKE

static __always_inline
int udp_dns_reply(struct cursor *c)
{
    struct udphdr  *udp;
    struct dnshdr  *dns;
 
    if (!(udp = parse_udphdr(c))|| udp->dest != __bpf_htons(DNS_PORT)
    ||  !(dns = parse_dnshdr(c)))
        return -1;
 

DRiKE

struct dns_qrr {
        uint16_t qtype;
        uint16_t qclass;
};
 
struct dns_rr {
        uint16_t type;
        uint16_t class;
        uint32_t ttl;
        uint16_t rdata_len;

DRiKE

static __always_inline
uint8_t *parse_dname(struct cursor *c, uint8_t *pkt)
{
        uint8_t *dname = c->pos;
 
        int  i;
        for (i = 0; i < 128; i++) { /* Maximum 128 labels */
                uint8_t o;
 
                if (c->pos + 1 > c->end)

DRiKE

struct dnshdr {
    uint16_t id;
    union {
        struct {
            uint8_t  rd     : 1;
            uint8_t  tc     : 1;
            uint8_t  aa     : 1;
            uint8_t  opcode : 4;
            uint8_t  qr     : 1;
 

DRiKE

SEC("xdp-dns-says-no-v1")
int xdp_dns_says_no(struct xdp_md *ctx)
{
    struct cursor   c;
    struct ethhdr  *eth;
    uint16_t        eth_proto;
    struct iphdr   *ipv4;
    struct ipv6hdr *ipv6;
 
    cursor_init(&c, ctx);

DRiKE

# Copyright 1999-2017 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

EAPI=6

inherit qmake-utils
inherit versionator

MY_PN="GoldenCheetah"
MY_PV=$(replace_version_separator 2 '-DEV')

DRiKE

#
# A fastbike could be a racing bike or a speed pedelec.
# But also at night or in rainy whether you might want
# to fallback to this one.
#
# Structure is similar to trekking.brf, see this for documenation.
# 

---context:global   # following code refers to global config

DRiKE

#include <stdio.h>
#include <pcap.h>
#include <arpa/inet.h>
#include <linux/if_ether.h>
#include <netinet/ip6.h>

#define SNAP_LEN	1500

int main(int argc, char *argv[]) {