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Diffstat (limited to 'src/libknot/xdp/xdp.h')
| -rw-r--r-- | src/libknot/xdp/xdp.h | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/src/libknot/xdp/xdp.h b/src/libknot/xdp/xdp.h new file mode 100644 index 0000000..a7606fe --- /dev/null +++ b/src/libknot/xdp/xdp.h @@ -0,0 +1,189 @@ +/* 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/>. + */ + +/*! + * \file + * + * \brief XDP IO interface. + * + * \addtogroup xdp + * @{ + */ + +#pragma once + +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <netinet/in.h> + +#include "libknot/xdp/bpf-consts.h" +#include "libknot/xdp/msg.h" + +/*! + * \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 Initialize XDP socket. + * + * \param socket XDP socket. + * \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 flags XDP filter configuration flags. + * \param udp_port UDP and/or TCP port to listen on if enabled via \a opts. + * \param quic_port QUIC/UDP port to listen on if enabled via \a opts. + * \param load_bpf Insert BPF program into packet processing. + * \param xdp_config Optional XDP socket configuration. + * + * \return KNOT_E* or -errno + */ +int knot_xdp_init(knot_xdp_socket_t **socket, const char *if_name, int if_queue, + knot_xdp_filter_flag_t flags, uint16_t udp_port, uint16_t quic_port, + knot_xdp_load_bpf_t load_bpf, const void *xdp_config); + +/*! + * \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 incoming 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 flags Flags for new message. + * \param out Out: the allocated packet buffer. + * + * \return KNOT_E* + */ +int knot_xdp_send_alloc(knot_xdp_socket_t *socket, knot_xdp_msg_flag_t flags, + knot_xdp_msg_t *out); + +/*! + * \brief Allocate one buffer for a reply packet. + * + * \param socket XDP socket. + * \param query The packet to be replied to. + * \param out Out: the allocated packet buffer. + * + * \return KNOT_E* + */ +int knot_xdp_reply_alloc(knot_xdp_socket_t *socket, const knot_xdp_msg_t *query, + knot_xdp_msg_t *out); + +/*! + * \brief Send multiple packets thru XDP. + * + * \note The packets all must have been allocated by knot_xdp_send_alloc()! + * \note Do not free the packet 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 Cleanup messages that have not been knot_xdp_send(). + * + * ...possibly due to some error. + * + * \param socket XDP socket. + * \param msgs Messages to be freed. + * \param count Number of messages. + */ +void knot_xdp_send_free(knot_xdp_socket_t *socket, const knot_xdp_msg_t msgs[], + uint32_t count); + +/*! + * \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 incoming packets. + * \param max_count Limit for number of packets received at once. + * \param count Out: real number of received packets. + * \param wire_size Out: (optional) total wire size 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, size_t *wire_size); + +/*! + * \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); + +/*! @} */ |