| /* MIT License |
| * |
| * Copyright (c) 2024 Brad House |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| * |
| * SPDX-License-Identifier: MIT |
| */ |
| #ifndef __ARES_CONN_H |
| #define __ARES_CONN_H |
| |
| #include "ares_socket.h" |
| |
| struct ares_conn; |
| typedef struct ares_conn ares_conn_t; |
| |
| struct ares_server; |
| typedef struct ares_server ares_server_t; |
| |
| typedef enum { |
| /*! No flags */ |
| ARES_CONN_FLAG_NONE = 0, |
| /*! TCP connection, not UDP */ |
| ARES_CONN_FLAG_TCP = 1 << 0, |
| /*! TCP Fast Open is enabled and being used if supported by the OS */ |
| ARES_CONN_FLAG_TFO = 1 << 1, |
| /*! TCP Fast Open has not yet sent its first packet. Gets unset on first |
| * write to a connection */ |
| ARES_CONN_FLAG_TFO_INITIAL = 1 << 2 |
| } ares_conn_flags_t; |
| |
| typedef enum { |
| ARES_CONN_STATE_NONE = 0, |
| ARES_CONN_STATE_READ = 1 << 0, |
| ARES_CONN_STATE_WRITE = 1 << 1, |
| ARES_CONN_STATE_CONNECTED = 1 << 2, /* This doesn't get a callback */ |
| ARES_CONN_STATE_CBFLAGS = ARES_CONN_STATE_READ | ARES_CONN_STATE_WRITE |
| } ares_conn_state_flags_t; |
| |
| struct ares_conn { |
| ares_server_t *server; |
| ares_socket_t fd; |
| struct ares_addr self_ip; |
| ares_conn_flags_t flags; |
| ares_conn_state_flags_t state_flags; |
| |
| /*! Outbound buffered data that is not yet sent. Exists as one contiguous |
| * stream in TCP format (big endian 16bit length prefix followed by DNS |
| * wire-format message). For TCP this can be sent as-is, UDP this must |
| * be sent per-packet (stripping the length prefix) */ |
| ares_buf_t *out_buf; |
| |
| /*! Inbound buffered data that is not yet parsed. Exists as one contiguous |
| * stream in TCP format (big endian 16bit length prefix followed by DNS |
| * wire-format message). TCP may have partial data and this needs to be |
| * handled gracefully, but UDP will always have a full message */ |
| ares_buf_t *in_buf; |
| |
| /* total number of queries run on this connection since it was established */ |
| size_t total_queries; |
| |
| /* list of outstanding queries to this connection */ |
| ares_llist_t *queries_to_conn; |
| }; |
| |
| /*! Various buckets for grouping history */ |
| typedef enum { |
| ARES_METRIC_1MINUTE = 0, /*!< Bucket for tracking over the last minute */ |
| ARES_METRIC_15MINUTES, /*!< Bucket for tracking over the last 15 minutes */ |
| ARES_METRIC_1HOUR, /*!< Bucket for tracking over the last hour */ |
| ARES_METRIC_1DAY, /*!< Bucket for tracking over the last day */ |
| ARES_METRIC_INCEPTION, /*!< Bucket for tracking since inception */ |
| ARES_METRIC_COUNT /*!< Count of buckets, not a real bucket */ |
| } ares_server_bucket_t; |
| |
| /*! Data metrics collected for each bucket */ |
| typedef struct { |
| time_t ts; /*!< Timestamp divided by bucket divisor */ |
| unsigned int latency_min_ms; /*!< Minimum latency for queries */ |
| unsigned int latency_max_ms; /*!< Maximum latency for queries */ |
| ares_uint64_t total_ms; /*!< Cumulative query time for bucket */ |
| ares_uint64_t total_count; /*!< Number of queries for bucket */ |
| |
| time_t prev_ts; /*!< Previous period bucket timestamp */ |
| ares_uint64_t |
| prev_total_ms; /*!< Previous period bucket cumulative query time */ |
| ares_uint64_t prev_total_count; /*!< Previous period bucket query count */ |
| } ares_server_metrics_t; |
| |
| typedef enum { |
| ARES_COOKIE_INITIAL = 0, |
| ARES_COOKIE_GENERATED = 1, |
| ARES_COOKIE_SUPPORTED = 2, |
| ARES_COOKIE_UNSUPPORTED = 3 |
| } ares_cookie_state_t; |
| |
| /*! Structure holding tracking data for RFC 7873/9018 DNS cookies. |
| * Implementation plan for this feature is here: |
| * https://github.com/c-ares/c-ares/issues/620 |
| */ |
| typedef struct { |
| /*! starts at INITIAL, transitions as needed. */ |
| ares_cookie_state_t state; |
| /*! randomly-generate client cookie */ |
| unsigned char client[8]; |
| /*! timestamp client cookie was generated, used for rotation purposes */ |
| ares_timeval_t client_ts; |
| /*! IP address last used for client to connect to server. If this changes |
| * The client cookie gets invalidated */ |
| struct ares_addr client_ip; |
| /*! Server Cookie last received, 8-32 bytes in length */ |
| unsigned char server[32]; |
| /*! Length of server cookie on file. */ |
| size_t server_len; |
| /*! Timestamp of last attempt to use cookies, but it was determined that the |
| * server didn't support them */ |
| ares_timeval_t unsupported_ts; |
| } ares_cookie_t; |
| |
| struct ares_server { |
| /* Configuration */ |
| size_t idx; /* index for server in system configuration */ |
| struct ares_addr addr; |
| unsigned short udp_port; /* host byte order */ |
| unsigned short tcp_port; /* host byte order */ |
| char ll_iface[64]; /* IPv6 Link Local Interface */ |
| unsigned int ll_scope; /* IPv6 Link Local Scope */ |
| |
| size_t consec_failures; /* Consecutive query failure count |
| * can be hard errors or timeouts |
| */ |
| ares_bool_t probe_pending; /* Whether a probe is pending for this |
| * server due to prior failures */ |
| ares_llist_t *connections; |
| ares_conn_t *tcp_conn; |
| |
| /* The next time when we will retry this server if it has hit failures */ |
| ares_timeval_t next_retry_time; |
| |
| /*! Buckets for collecting metrics about the server */ |
| ares_server_metrics_t metrics[ARES_METRIC_COUNT]; |
| |
| /*! RFC 7873/9018 DNS Cookies */ |
| ares_cookie_t cookie; |
| |
| /* Link back to owning channel */ |
| ares_channel_t *channel; |
| }; |
| |
| void ares_close_connection(ares_conn_t *conn, ares_status_t requeue_status); |
| void ares_close_sockets(ares_server_t *server); |
| void ares_check_cleanup_conns(const ares_channel_t *channel); |
| |
| void ares_destroy_servers_state(ares_channel_t *channel); |
| ares_status_t ares_open_connection(ares_conn_t **conn_out, |
| ares_channel_t *channel, |
| ares_server_t *server, ares_bool_t is_tcp); |
| |
| ares_conn_err_t ares_conn_write(ares_conn_t *conn, const void *data, size_t len, |
| size_t *written); |
| ares_status_t ares_conn_flush(ares_conn_t *conn); |
| ares_conn_err_t ares_conn_read(ares_conn_t *conn, void *data, size_t len, |
| size_t *read_bytes); |
| ares_conn_t *ares_conn_from_fd(const ares_channel_t *channel, ares_socket_t fd); |
| void ares_conn_sock_state_cb_update(ares_conn_t *conn, |
| ares_conn_state_flags_t flags); |
| ares_conn_err_t ares_socket_recv(ares_channel_t *channel, ares_socket_t s, |
| ares_bool_t is_tcp, void *data, |
| size_t data_len, size_t *read_bytes); |
| ares_conn_err_t ares_socket_recvfrom(ares_channel_t *channel, ares_socket_t s, |
| ares_bool_t is_tcp, void *data, |
| size_t data_len, int flags, |
| struct sockaddr *from, |
| ares_socklen_t *from_len, |
| size_t *read_bytes); |
| |
| void ares_destroy_server(ares_server_t *server); |
| |
| #endif |
