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Diffstat (limited to '')
| -rw-r--r-- | src/libknot/xdp/xdp.h | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/libknot/xdp/xdp.h b/src/libknot/xdp/xdp.h new file mode 100644 index 0000000..74a845a --- /dev/null +++ b/src/libknot/xdp/xdp.h @@ -0,0 +1,167 @@ +/* Copyright (C) 2020 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 <stdint.h> +#include <stdio.h> +#include <netinet/in.h> + +#include "libknot/xdp/bpf-consts.h" + +#ifdef ENABLE_XDP +#define KNOT_XDP_AVAILABLE 1 +#endif + +/*! \brief A packet with src & dst MAC & IP addrs + UDP payload. */ +typedef struct knot_xdp_msg knot_xdp_msg_t; +struct knot_xdp_msg { + struct sockaddr_in6 ip_from; + struct sockaddr_in6 ip_to; + uint8_t *eth_from; + uint8_t *eth_to; + struct iovec payload; +}; + +/*! + * \brief Styles of loading BPF program. + * + * \note In *all* the cases loading can only succeed if at the end + * a compatible BPF program is loaded on the interface. + */ +typedef enum { + KNOT_XDP_LOAD_BPF_NEVER, /*!< Do not load; error out if not loaded already. */ + KNOT_XDP_LOAD_BPF_ALWAYS, /*!< Always load a program (overwrite it). */ + KNOT_XDP_LOAD_BPF_ALWAYS_UNLOAD, /*!< KNOT_XDP_LOAD_BPF_ALWAYS + unload previous. */ + KNOT_XDP_LOAD_BPF_MAYBE, /*!< Try with present program or load if none. */ + /* Implementation caveat: when re-using program in _MAYBE case, we get a message: + * libbpf: Kernel error message: XDP program already attached */ +} knot_xdp_load_bpf_t; + +/*! \brief Context structure for one XDP socket. */ +typedef struct knot_xdp_socket knot_xdp_socket_t; + +/*! \brief Offset of DNS payload inside ethernet frame (IPv4 and v6 variants). */ +extern const size_t KNOT_XDP_PAYLOAD_OFFSET4; +extern const size_t KNOT_XDP_PAYLOAD_OFFSET6; + +/*! + * \brief Initialize XDP socket. + * + * \param socket Socket ctx. + * \param if_name Name of the net iface (e.g. eth0). + * \param if_queue Network card queue to be used (normally 1 socket per each queue). + * \param listen_port Port to listen on, or KNOT_XDP_LISTEN_PORT_* flag. + * \param load_bpf Insert BPF program into packet processing. + * + * \return KNOT_E* or -errno + */ +int knot_xdp_init(knot_xdp_socket_t **socket, const char *if_name, int if_queue, + uint32_t listen_port, knot_xdp_load_bpf_t load_bpf); + +/*! + * \brief De-init XDP socket. + * + * \param socket XDP socket. + */ +void knot_xdp_deinit(knot_xdp_socket_t *socket); + +/*! + * \brief Return a file descriptor to be polled on for incomming packets. + * + * \param socket XDP socket. + * + * \return KNOT_E* + */ +int knot_xdp_socket_fd(knot_xdp_socket_t *socket); + +/*! + * \brief Collect completed TX buffers, so they can be used by knot_xdp_send_alloc(). + * + * \param socket XDP socket. + */ +void knot_xdp_send_prepare(knot_xdp_socket_t *socket); + +/*! + * \brief Allocate one buffer for an outgoing packet. + * + * \param socket XDP socket. + * \param ipv6 The packet will use IPv6 (IPv4 otherwise). + * \param out Out: the allocated packet buffer. + * \param in_reply_to Optional: fill in addresses from this query. + * + * \return KNOT_E* + */ +int knot_xdp_send_alloc(knot_xdp_socket_t *socket, bool ipv6, knot_xdp_msg_t *out, + const knot_xdp_msg_t *in_reply_to); + +/*! + * \brief Send multiple packets thru XDP. + * + * \note The packets all must have been allocated by knot_xdp_send_alloc()! + * \note Do not free the packets payloads afterwards. + * \note Packets with zero length will be skipped. + * + * \param socket XDP socket. + * \param msgs Packets to be sent. + * \param count Number of packets. + * \param sent Out: number of packet successfully sent. + * + * \return KNOT_E* + */ +int knot_xdp_send(knot_xdp_socket_t *socket, const knot_xdp_msg_t msgs[], + uint32_t count, uint32_t *sent); + +/*! + * \brief Syscall to kernel to wake up the network card driver after knot_xdp_send(). + * + * \param socket XDP socket. + * + * \return KNOT_E* or -errno + */ +int knot_xdp_send_finish(knot_xdp_socket_t *socket); + +/*! + * \brief Receive multiple packets thru XDP. + * + * \param socket XDP socket. + * \param msgs Out: buffers to be filled in with incomming packets. + * \param max_count Limit for number of packets received at once. + * \param count Out: real number of received packets. + * + * \return KNOT_E* + */ +int knot_xdp_recv(knot_xdp_socket_t *socket, knot_xdp_msg_t msgs[], + uint32_t max_count, uint32_t *count); + +/*! + * \brief Free buffers with received packets. + * + * \param socket XDP socket. + * \param msgs Buffers with received packets. + * \param count Number of received packets to free. + */ +void knot_xdp_recv_finish(knot_xdp_socket_t *socket, const knot_xdp_msg_t msgs[], + uint32_t count); + +/*! + * \brief Print some info about the XDP socket. + * + * \param socket XDP socket. + * \param file Output file. + */ +void knot_xdp_info(const knot_xdp_socket_t *socket, FILE *file); |