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103 lines
3.2 KiB
103 lines
3.2 KiB
3 years ago
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#pragma once
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#include <assert.h>
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#include <errno.h>
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#include <netdb.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h>
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#include "debuglog.h"
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#include "likely.h"
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/*
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* Defines the listen backlog, the queue length for completely established socketeds waiting to be accepted
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* If this value is greater than the value in /proc/sys/net/core/somaxconn (typically 128), then it is silently
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* truncated to this value. See man listen(2) for info
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*
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* When configuring the number of sockets to handle, the queue length of incomplete sockets defined in
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* /proc/sys/net/ipv4/tcp_max_syn_backlog should also be considered. Optionally, enabling syncookies removes this
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* maximum logical length. See tcp(7) for more info.
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*/
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#define TCP_SERVER_MAX_PENDING_CLIENT_REQUESTS 128
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#if TCP_SERVER_MAX_PENDING_CLIENT_REQUESTS > 128
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#warning \
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"TCP_SERVER_MAX_PENDING_CLIENT_REQUESTS likely exceeds the value in /proc/sys/net/core/somaxconn and thus may be silently truncated";
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#endif
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/* L4 TCP State */
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struct tcp_server {
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uint16_t port;
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struct sockaddr_in socket_address;
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int socket_descriptor;
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};
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static inline void
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tcp_server_init(struct tcp_server *server, uint16_t port)
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{
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server->port = port;
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server->socket_descriptor = -1;
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}
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/**
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* Start the module as a server listening at module->port
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* @param module
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* @returns 0 on success, -1 on error
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*/
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static inline int
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tcp_server_listen(struct tcp_server *server)
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{
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int rc;
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int optval = 1;
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/* Allocate a new TCP/IP socket, setting it to be non-blocking */
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int socket_descriptor = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
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if (unlikely(socket_descriptor < 0)) goto err_create_socket;
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/* Socket should never have returned on fd 0, 1, or 2 */
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assert(socket_descriptor != STDIN_FILENO);
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assert(socket_descriptor != STDOUT_FILENO);
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assert(socket_descriptor != STDERR_FILENO);
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/* Configure the socket to allow multiple sockets to bind to the same host and port */
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rc = setsockopt(socket_descriptor, SOL_SOCKET, SO_REUSEPORT, &optval, sizeof(optval));
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if (unlikely(rc < 0)) goto err_set_socket_option;
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optval = 1;
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rc = setsockopt(socket_descriptor, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
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if (unlikely(rc < 0)) goto err_set_socket_option;
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/* Bind name [all addresses]:[module->port] to socket */
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server->socket_descriptor = socket_descriptor;
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server->socket_address.sin_family = AF_INET;
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server->socket_address.sin_addr.s_addr = htonl(INADDR_ANY);
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server->socket_address.sin_port = htons((unsigned short)server->port);
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rc = bind(socket_descriptor, (struct sockaddr *)&server->socket_address, sizeof(server->socket_address));
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if (unlikely(rc < 0)) goto err_bind_socket;
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/* Listen to the interface */
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rc = listen(socket_descriptor, TCP_SERVER_MAX_PENDING_CLIENT_REQUESTS);
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if (unlikely(rc < 0)) goto err_listen;
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rc = 0;
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done:
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return rc;
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err_listen:
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err_bind_socket:
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server->socket_descriptor = -1;
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err_set_socket_option:
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close(socket_descriptor);
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err_create_socket:
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err:
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debuglog("Socket Error: %s", strerror(errno));
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rc = -1;
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goto done;
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}
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static inline int
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tcp_server_close(struct tcp_server *server)
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{
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return close(server->socket_descriptor);
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}
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