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/* Copyright (C) 2023 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 <sys/socket.h>
#include <sys/stat.h>
// 1280 (IPv6 minimum link MTU) - 40 (IPv6 fixed header) - 20 (TCP fixed header)
#define KNOT_TCP_MSS 1220
/*!
* \brief Network interface flags.
*/
typedef enum {
NET_BIND_NONLOCAL = (1 << 0), //!< Allow to bind unavailable address.
NET_BIND_MULTIPLE = (1 << 1), //!< Allow to bind address multiple times.
} net_bind_flag_t;
/*!
* \brief Create unbound socket of given family and type.
*
* \note The socket is set to non-blocking mode.
*
* \param type Socket transport type (SOCK_STREAM, SOCK_DGRAM).
* \param addr Socket address.
*
* \return socket or error code
*/
int net_unbound_socket(int type, const struct sockaddr_storage *addr);
/*!
* \brief Create socket bound to given address.
*
* The socket is set to non-blocking mode.
*
* \param type Socket transport type (SOCK_STREAM, SOCK_DGRAM).
* \param addr Socket address.
* \param flags Socket binding options.
* \param unix_mode Socket file mode (UNIX socket only). 0 means don't set mode.
*
* \return socket or error code
*/
int net_bound_socket(int type, const struct sockaddr_storage *addr,
net_bind_flag_t flags, mode_t unix_mode);
/*!
* \brief Create socket connected (asynchronously) to destination address.
*
* \note The socket is set to non-blocking mode.
*
* \param type Socket transport type (SOCK_STREAM, SOCK_DGRAM).
* \param dst_addr Destination address.
* \param src_addr Source address (can be NULL).
* \param tfo Enable TCP Fast Open.
*
* \return socket or error code
*/
int net_connected_socket(int type, const struct sockaddr_storage *dst_addr,
const struct sockaddr_storage *src_addr, bool tfo);
/*!
* \brief Enables TCP Fast Open on a bound socket.
*
* \param sock Socket.
*
* \return KNOT_EOK or error code
*/
int net_bound_tfo(int sock, int backlog);
/*!
* \brief Tell kernel to send ECN bits thru CMSG on packet receival.
*
* \param sock Socket to enable receiving ECN bits.
* \param family Address family on that socket.
*
* \return KNOT_E*
*/
int net_cmsg_ecn_enable(int sock, int family);
/*!
* \brief Return pointer to possible ECN value in cmsg.
*
* \note The function also updates cmsg_type for outgoing use.
*
* \param cmsg Received control message.
*
* \return Pointer to ECN value or NULL.
*/
int *net_cmsg_ecn_ptr(struct cmsghdr *cmsg);
/*!
* \brief Get ECN bits of packets received by recv(m)msg.
*
* \param msg Received message header.
*
* \return 0..3
*/
uint8_t net_cmsg_ecn(struct msghdr *msg);
/*!
* \brief Set ECN for outgoing packets on this socket.
*
* \param sock Socket file descriptor.
* \param family Address family for outgoing packets.
* \param ecn ECN bits to be set.
*
* \return KNOT_E*
*/
int net_ecn_set(int sock, int family, uint8_t ecn);
/*!
* \brief Return true if the socket is fully connected.
*
* \param sock Socket.
*
* \return true if connected
*/
bool net_is_connected(int sock);
/*!
* \brief Get socket type (e.g. \a SOCK_STREAM).
*
* \param sock Socket.
*/
int net_socktype(int sock);
/*!
* \brief Check if socket is a SOCK_STREAM socket.
*/
bool net_is_stream(int sock);
/*!
* \brief Accept a connection on a listening socket.
*
* \brief The socket is set to non-blocking mode.
*
* \param sock Socket
* \param addr Remote address (can be NULL).
*
* \return socket or error code
*/
int net_accept(int sock, struct sockaddr_storage *addr);
/*!
* \brief Reset a TCP connection (with a RST packet).
*/
void net_reset(int sock);
/*!
* \brief Send a message on a socket.
*
* The socket can be SOCK_STREAM or SOCK_DGRAM.
*
* The implementation handles partial-writes automatically.
*
* \param[in] sock Socket.
* \param[in] buffer Message buffer.
* \param[in] size Size of the message.
* \param[in] addr Remote address (ignored for SOCK_STREAM).
* \param[in] timeout_ms Write timeout in milliseconds (-1 for infinity,
* not valid for SOCK_DGRAM).
*
* \return Number of bytes sent or negative error code.
*/
ssize_t net_base_send(int sock, const uint8_t *buffer, size_t size,
const struct sockaddr_storage *addr, int timeout_ms);
/*!
* \brief Receive a message from a socket.
*
* \param[in] sock Socket.
* \param[out] buffer Receiving buffer.
* \param[in] size Capacity of the receiving buffer.
* \param[out] addr Remote address (can be NULL).
* \param[in] timeout_ms Read timeout in milliseconds (-1 for infinity).
*
* \return Number of bytes read or negative error code.
*/
ssize_t net_base_recv(int sock, uint8_t *buffer, size_t size,
struct sockaddr_storage *addr, int timeout_ms);
/*!
* \brief Send a message with prepared msghdr structure.
*
* \see net_base_send
*/
ssize_t net_msg_send(int sock, struct msghdr *msg, int timeout_ms);
/*!
* \brief Receive a message into msghdr structure.
*
* \see net_base_send
*/
ssize_t net_msg_recv(int sock, struct msghdr *msg, int timeout_ms);
/*!
* \brief Send a message on a SOCK_DGRAM socket.
*
* \see net_base_send
*/
ssize_t net_dgram_send(int sock, const uint8_t *buffer, size_t size,
const struct sockaddr_storage *addr);
/*!
* \brief Receive a message from a SOCK_DGRAM socket.
*
* \see net_base_recv
*/
ssize_t net_dgram_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms);
/*!
* \brief Send a message on a SOCK_STREAM socket.
*
* \see net_base_send
*/
ssize_t net_stream_send(int sock, const uint8_t *buffer, size_t size, int timeout_ms);
/*!
* \brief Receive a message from a SOCK_STREAM socket.
*
* \see net_base_recv
*/
ssize_t net_stream_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms);
/*!
* \brief Send a DNS message on a TCP socket.
*
* The outgoing message is prefixed with a two-byte value carrying the DNS
* message size according to the specification. These two bytes are not
* reflected in the return value.
*
* \param[in] tfo_addr If not NULL, send using TCP Fast Open to this address.
*
* \see net_base_send
*/
ssize_t net_dns_tcp_send(int sock, const uint8_t *buffer, size_t size, int timeout_ms,
struct sockaddr_storage *tfo_addr);
/*!
* \brief Receive a DNS message from a TCP socket.
*
* The first two bytes of the incoming message are interpreted as a DNS message
* size according to the specification. These two bytes are not included in
* the returned size. Only a complete DNS message is retrieved.
*
* \see net_base_recv
*/
ssize_t net_dns_tcp_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms);
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