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sockets.c
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sockets.c
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// Copyright 2020 Bonedaddy (Alexandre Trottier)
//
// licensed under GNU AFFERO GENERAL PUBLIC LICENSE;
// you may not use this file except in compliance with the License;
// You may obtain the license via the LICENSE file in the repository root;
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "sockets.h"
#include "deps/ulog/logger.h"
#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
/*!
* @brief creates a new client socket
* @todo should we enable usage of socket options
*/
socket_client_t *new_client_socket(thread_logger *thl, char *ip, char *port,
bool tcp, bool ipv4) {
addr_info hints = new_addr_info_hints(ipv4, tcp, true);
addr_info *peer_address;
int rc = getaddrinfo(ip, port, &hints, &peer_address);
if (rc != 0) {
freeaddrinfo(peer_address);
return NULL;
}
int client_socket_num = get_new_socket(thl, peer_address, NULL, 0, true, tcp);
if (client_socket_num == -1) {
LOG_ERROR(thl, 0, "failed to get new socket");
freeaddrinfo(peer_address);
return NULL;
}
socket_client_t *sock_client =
calloc(1, sizeof(sock_client) + sizeof(peer_address));
if (sock_client == NULL) {
LOG_ERROR(thl, 0, "failed to calloc socket_client_t");
return NULL;
}
sock_client->socket_number = client_socket_num;
sock_client->peer_address = peer_address;
LOG_INFO(thl, 0, "client successfully created");
return sock_client;
}
/*!
* @brief used to accept a connection queued up against the given socket
* @details it accepts an incoming connection on the socket returning
* @details the socket number that can be used to communicate on this connection
*/
int accept_socket(thread_logger *thl, int socket) {
sock_addr_storage incoming_address;
socklen_t addr_size = sizeof(incoming_address);
int new_fd = accept(socket, (struct sockaddr *)&incoming_address, &addr_size);
if (new_fd == -1) {
LOGF_ERROR(thl, 0, "failed to accept connection %s", strerror(errno));
return -1;
}
char hoststr[1025];
char portstr[32];
int rc = getnameinfo((struct sockaddr *)&incoming_address, addr_size, hoststr,
sizeof(hoststr), portstr, sizeof(portstr),
NI_NUMERICHOST | NI_NUMERICSERV);
if (rc == 0) {
LOGF_DEBUG(thl, 0, "accepted connection. ip: %s, port %s", hoststr, portstr);
}
return new_fd;
}
/*!
* @brief attempts to create a socket listening on the specified ip and port
* @details this is a helper function to abstract away the verbosity required to
* create a socket
*/
int listen_socket(thread_logger *thl, char *ip, char *port, bool tcp, bool ipv4,
SOCKET_OPTS sock_opts[], int num_opts) {
if (sock_opts == NULL || num_opts == 0) {
LOG_ERROR(thl, 0, "empty socket opts");
return -1;
}
addr_info hints = new_addr_info_hints(ipv4, tcp, false);
addr_info *bind_address;
int rc = getaddrinfo(ip, port, &hints, &bind_address);
if (rc != 0) {
freeaddrinfo(bind_address);
return -1;
}
int socket_num = get_new_socket(thl, bind_address, sock_opts, 2, false, tcp);
freeaddrinfo(bind_address);
if (socket_num == -1) {
LOG_ERROR(thl, 0, "failed to get new socket");
}
// if this is is a udp sockets, no need to start the listener
// only tcp sockets need to do this
if (tcp) {
rc = listen(socket_num, 10); // todo: enable customizable connection count
if (rc == -1) {
LOGF_ERROR(thl, 0, "failed to listen on tcp socket %s", strerror(errno));
return -1;
}
}
return socket_num;
}
/*! @brief gets an available socket attached to bind_address
* @return Success: file descriptor socket number greater than 0
* @return Failure: -1
* initializers a socket attached to bind_address with sock_opts, and binds the
* address
*/
int get_new_socket(thread_logger *thl, addr_info *bind_address,
SOCKET_OPTS sock_opts[], int num_opts, bool client, bool tcp) {
// creates the socket and gets us its file descriptor
int listen_socket_num =
socket(bind_address->ai_family, bind_address->ai_socktype,
bind_address->ai_protocol);
// less than 0 is an error
if (listen_socket_num < 0) {
LOG_ERROR(thl, 0, "socket creation failed");
return -1;
}
int one;
int rc;
bool passed;
for (int i = 0; i < num_opts; i++) {
switch (sock_opts[i]) {
case REUSEADDR:
one = 1;
// set socket options before doing anything else
// i tried setting it after listen, but I don't think that works
rc = setsockopt(listen_socket_num, SOL_SOCKET, SO_REUSEADDR, &one,
sizeof(int));
if (rc != 0) {
LOG_ERROR(thl, 0, "failed to set socket reuse addr");
return -1;
}
LOG_INFO(thl, 0, "set socket opt REUSEADDR");
break;
case BLOCK:
passed = set_socket_blocking_status(listen_socket_num, true);
if (passed == false) {
LOG_ERROR(thl, 0, "failed to set socket blocking mode");
return -1;
}
LOG_INFO(thl, 0, "set socket opt BLOCK");
break;
case NOBLOCK:
passed = set_socket_blocking_status(listen_socket_num, false);
if (passed == false) {
LOG_ERROR(thl, 0, "failed to set socket blocking mode");
return -1;
}
LOG_INFO(thl, 0, "set socket opt NOBLOCK");
break;
default:
LOG_ERROR(thl, 0, "invalid socket option");
return -1;
}
}
if (client == true) {
if (tcp == true) {
/*! @todo should we do this on UDP connections?? */
rc = connect(listen_socket_num, bind_address->ai_addr,
bind_address->ai_addrlen);
if (rc != 0) {
close(listen_socket_num);
return -1;
}
}
return listen_socket_num;
}
// binds the address to the socket
bind(listen_socket_num, bind_address->ai_addr, bind_address->ai_addrlen);
if (errno != 0) {
LOGF_ERROR(thl, 0, "socket bind failed with error %s", strerror(errno));
return -1;
}
return listen_socket_num;
}
/*! @brief used to enable/disable blocking sockets
* @return Failure: false
* @return Success: true
* @note see
* https://stackoverflow.com/questions/1543466/how-do-i-change-a-tcp-socket-to-be-non-blocking/1549344#1549344
*/
bool set_socket_blocking_status(int fd, bool blocking) {
if (fd < 0) {
return false;
} else {
int flags = fcntl(fd, F_GETFL, 0);
if (flags == -1) {
return false;
}
flags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
return (fcntl(fd, F_SETFL, flags) == 0) ? true : false;
}
}
/*! @brief returns the address the client is connecting from
*/
char *get_name_info(sock_addr *client_address) {
char address_info[256]; // destroy when function returns
getnameinfo(client_address, sizeof(*client_address),
address_info, // output buffer
sizeof(address_info), // size of the output buffer
0, // second buffer which outputs service name
0, // length of the second buffer
NI_NUMERICHOST // want to see hostnmae as an ip address
);
char *addr = malloc(sizeof(address_info));
if (addr == NULL) {
return NULL;
}
strcpy(addr, address_info);
return addr;
}
/*!
* @brief generates an addr_info struct with settings for
* being used to socket creation
*/
addr_info new_addr_info_hints(bool ipv4, bool tcp, bool client) {
addr_info hints;
memset(&hints, 0, sizeof(hints));
if (ipv4) {
hints.ai_family = AF_INET;
} else {
hints.ai_family = AF_INET6;
}
if (tcp) {
hints.ai_socktype = SOCK_STREAM;
} else {
hints.ai_socktype = SOCK_DGRAM;
}
// todo enable ai_flags control this is rudimentary
if (client) {
// indicates bind to wildcard address
hints.ai_flags = AI_PASSIVE;
}
return hints;
}
void free_socket_client_t(socket_client_t *sock_client) {
close(sock_client->socket_number);
freeaddrinfo(sock_client->peer_address);
free(sock_client);
}