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/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include <stdbool.h>
#include <string.h>
#include "libknot/xdp/msg.h"
#include "libknot/xdp/tcp.h"
#include "libdnssec/random.h"
inline static bool empty_msg(const knot_xdp_msg_t *msg)
{
const unsigned tcp_flags = KNOT_XDP_MSG_SYN | KNOT_XDP_MSG_ACK |
KNOT_XDP_MSG_FIN | KNOT_XDP_MSG_RST;
return (msg->payload.iov_len == 0 && !(msg->flags & tcp_flags));
}
inline static void msg_init_base(knot_xdp_msg_t *msg, knot_xdp_msg_flag_t flags)
{
memset(msg, 0, sizeof(*msg));
msg->flags = flags;
}
inline static void msg_init(knot_xdp_msg_t *msg, knot_xdp_msg_flag_t flags)
{
msg_init_base(msg, flags);
if (flags & KNOT_XDP_MSG_TCP) {
msg->ackno = 0;
msg->seqno = dnssec_random_uint32_t();
if (flags & KNOT_XDP_MSG_SYN) {
msg->flags |= KNOT_XDP_MSG_MSS | KNOT_XDP_MSG_WSC;
}
}
}
inline static void msg_init_reply(knot_xdp_msg_t *msg, const knot_xdp_msg_t *query)
{
msg_init_base(msg, query->flags & (KNOT_XDP_MSG_IPV6 | KNOT_XDP_MSG_TCP |
KNOT_XDP_MSG_MSS | KNOT_XDP_MSG_WSC));
memcpy(msg->eth_from, query->eth_to, ETH_ALEN);
memcpy(msg->eth_to, query->eth_from, ETH_ALEN);
memcpy(&msg->ip_from, &query->ip_to, sizeof(msg->ip_from));
memcpy(&msg->ip_to, &query->ip_from, sizeof(msg->ip_to));
msg->vlan_tci = query->vlan_tci;
if (msg->flags & KNOT_XDP_MSG_TCP) {
msg->ackno = knot_tcp_next_seqno(query);
msg->seqno = query->ackno;
if (msg->seqno == 0) {
msg->seqno = dnssec_random_uint32_t();
}
}
}
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