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/** \file server/sock.c
* This file contains all the sockets code used by the server. This contains
* the code called upon by main() to initialize the listening socket, as well
* as code to deal with sending messages to clients, maintaining connections,
* accepting new connections, closing dead connections (or connections
* associated with dying/exiting clients), etc.
*/
/* This file is part of LCDd, the lcdproc server.
*
* This file is released under the GNU General Public License.
* Refer to the COPYING file distributed with this package.
*
* Copyright (c) 1999, William Ferrell, Selene Scriven
* 2004, F5 Networks, Inc. - IP-address input
* 2005, Peter Marschall - error checks, ...
* 2009, Markus Dolze - input ring buffer
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <unistd.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include "shared/report.h"
#include "shared/sring.h"
#include "shared/defines.h"
#include "clients.h"
#include "sock.h"
/****************************************************************************/
static fd_set active_fd_set, read_fd_set;
static int listening_fd;
/* For efficiency we maintain a list of open sockets. Nodes in this list
* are obtained from a pre-allocated pool - this removes heap operations
* from the polling loop. A list of open sockets is also required under WINSOCK
* as sockets can be arbitrary values instead of low value integers. */
static LinkedList* openSocketList = NULL;
static LinkedList* freeClientSocketList = NULL;
/* ring buffer for incoming messages */
static sring_buffer *messageRing;
/** Mapping between socket and associated client */
typedef struct _ClientSocketMap
{
int socket; /**< Socket for the client */
Client *client; /**< Pointer to client representation */
} ClientSocketMap;
/* The memory referenced from \c openSocketList and \c freeSocketList
* is obtained from the freeClientSocketPool array. */
ClientSocketMap *freeClientSocketPool;
/* Length of longest transmission allowed at once...*/
#define MAXMSG 8192
/**** Internal function declarations ****************************************/
static int sock_read_from_client(ClientSocketMap *clientSocketMap);
static void sock_destroy_socket(void);
/** Initialize sockets.
* Prepare server socket, and initialize socket management structures.
* \param bind_addr Hostname / IP address to bind to.
* \param bind_port Port to bind to.
* \retval <0 error
* \retval 0 success
*/
int
sock_init(char* bind_addr, int bind_port)
{
int i;
debug(RPT_DEBUG, "%s(bind_addr=\"%s\", port=%d)", __FUNCTION__, bind_addr, bind_port);
/* Create the socket and set it up to accept connections. */
listening_fd = sock_create_inet_socket(bind_addr, bind_port);
if (listening_fd < 0) {
report(RPT_ERR, "%s: error creating socket - %s",
__FUNCTION__, sock_geterror());
return -1;
}
/* Create the socket -> Client mapping pool */
/* How large can FD_SETSIZE be? Even if it is ~2000 this only uses a
few kilobytes of memory. Let's trade size for speed! */
freeClientSocketPool = (ClientSocketMap *)
calloc(FD_SETSIZE, sizeof(ClientSocketMap));
if (freeClientSocketPool == NULL) {
report(RPT_ERR, "%s: Error allocating client sockets.",
__FUNCTION__);
return -1;
}
freeClientSocketList = LL_new();
if (freeClientSocketList == NULL) {
report(RPT_ERR, "%s: error allocating free socket list.",
__FUNCTION__);
return -1;
}
for (i = 0; i < FD_SETSIZE; ++i) {
LL_AddNode(freeClientSocketList, (void*) &freeClientSocketPool[i]);
}
/* Create and initialize the open socket list with the server socket */
openSocketList = LL_new();
if (openSocketList == NULL) {
report(RPT_ERR, "%s: error allocating open socket list.",
__FUNCTION__);
return -1;
}
else {
ClientSocketMap *entry;
entry = (ClientSocketMap*) LL_Pop(freeClientSocketList);
entry->socket = listening_fd;
entry->client = NULL;
LL_AddNode(openSocketList, (void*) entry);
}
if ((messageRing = sring_create(MAXMSG)) == NULL) {
report(RPT_ERR, "%s: error allocating receive buffer.",
__FUNCTION__);
return -1;
}
return 0;
}
/** Cleanup socket management structures.
* \retval <0 error
* \retval 0 success
*/
int
sock_shutdown(void)
{
int retVal = 0;
debug(RPT_DEBUG, "%s()", __FUNCTION__);
/*ClientSocketMap* clientIt;*/
/* delete all clients */
/* This should be done by calling clients_shutdown */
/*
LL_Rewind(openSocketList);
for (clientIt = (ClientSocketMap*) LL_Get(openSocketList);
clientIt;
clientIt = LL_GetNext(openSocketList))
{
if (clientIt->client)
{
*/
/* destroying a client also closes its socket */
/* client_destroy(clientIt->client);
}
}
LL_Destroy(openSocketList);
*/
close(listening_fd);
LL_Destroy(freeClientSocketList);
free(freeClientSocketPool);
sring_destroy(messageRing);
return retVal;
}
/** Create an INET socket, bind to it and listen on it.
* \param addr Hostname / IP address to bind to.
* \param port Port to bind to.
* \retval <0 error
* \retval 0 success
*/
int
sock_create_inet_socket(char *addr, unsigned int port)
{
struct sockaddr_in name;
int sock;
int sockopt = 1;
debug(RPT_DEBUG, "%s(addr=\"%s\", port=%i)", __FUNCTION__, addr, port);
/* Create the socket. */
sock = socket(PF_INET, SOCK_STREAM, 0);
if (sock < 0)
{
report(RPT_ERR, "%s: cannot create socket - %s",
__FUNCTION__, sock_geterror());
return -1;
}
/* Set the socket so we can re-use it*/
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *) &sockopt, sizeof(sockopt)) < 0) {
report(RPT_ERR, "%s: error setting socket option SO_REUSEADDR - %s",
__FUNCTION__, sock_geterror());
return -1;
}
/* Give the socket a name. */
memset(&name, 0, sizeof(name));
name.sin_family = AF_INET;
name.sin_port = htons(port);
inet_aton(addr, &name.sin_addr);
if (bind(sock, (struct sockaddr *) &name, sizeof(name)) < 0) {
report(RPT_ERR, "%s: cannot bind to port %d at address %s - %s",
__FUNCTION__, port, addr, sock_geterror());
return -1;
}
if (listen(sock, 1) < 0) {
report(RPT_ERR, "%s: error in attempting to listen to port "
"%d at %s - %s",
__FUNCTION__, port, addr, sock_geterror());
return -1;
}
report(RPT_NOTICE, "Listening for queries on %s:%d", addr, port);
/* Initialize the set of active sockets. */
FD_ZERO(&active_fd_set);
FD_SET(sock, &active_fd_set);
return sock;
}
/** Service all clients with pending input.
* \retval <0 error
* \retval 0 success
*/
int
sock_poll_clients(void)
{
struct timeval t;
ClientSocketMap* clientSocket;
debug(RPT_DEBUG, "%s()", __FUNCTION__);
t.tv_sec = 0;
t.tv_usec = 0;
/* Block until input arrives on one or more active sockets. */
read_fd_set = active_fd_set;
if (select(FD_SETSIZE, &read_fd_set, NULL, NULL, &t) < 0) {
report(RPT_ERR, "%s: Select error - %s",
__FUNCTION__, sock_geterror());
return -1;
}
/* Service all the sockets with input pending. */
LL_Rewind(openSocketList);
for (clientSocket = (ClientSocketMap *) LL_Get(openSocketList);
clientSocket != NULL;
clientSocket = LL_GetNext(openSocketList)) {
if (FD_ISSET(clientSocket->socket, &read_fd_set)) {
if (clientSocket->socket == listening_fd) {
/* Connection request on original socket. */
Client *c;
int new_sock;
struct sockaddr_in clientname;
socklen_t size = sizeof(clientname);
new_sock = accept(listening_fd, (struct sockaddr *) &clientname, &size);
if (new_sock < 0) {
report(RPT_ERR, "%s: Accept error - %s",
__FUNCTION__, sock_geterror());
return -1;
}
report(RPT_NOTICE, "Connect from host %s:%hu on socket %i",
inet_ntoa(clientname.sin_addr), ntohs(clientname.sin_port), new_sock);
FD_SET(new_sock, &active_fd_set);
fcntl(new_sock, F_SETFL, O_NONBLOCK);
/* Create new client */
if ((c = client_create(new_sock)) == NULL) {
report(RPT_ERR, "%s: Error creating client on socket %i - %s",
__FUNCTION__, clientSocket->socket, sock_geterror());
return -1;
}
else {
/* add new_sock */
ClientSocketMap *newClientSocket;
newClientSocket = (ClientSocketMap *) LL_Pop(freeClientSocketList);
if (newClientSocket != NULL) {
newClientSocket->socket = new_sock;
newClientSocket->client = c;
LL_InsertNode(openSocketList, (void *) newClientSocket);
/* advance past the new node - check it on the next pass */
LL_Next(openSocketList);
}
else {
report(RPT_ERR, "%s: Error - free client socket list exhausted - %d clients.",
__FUNCTION__, FD_SETSIZE);
return -1;
}
}
if (clients_add_client(c) == NULL) {
report(RPT_ERR, "%s: Could not add client on socket %i",
__FUNCTION__, clientSocket->socket);
return -1;
}
}
else { /* Data arriving on an already-connected socket. */
int err = 0;
debug(RPT_DEBUG, "%s: reading...", __FUNCTION__);
err = sock_read_from_client(clientSocket);
debug(RPT_DEBUG, "%s: ...done", __FUNCTION__);
if (err < 0)
sock_destroy_socket();
}
}
}
return 0;
}
/** Read from a client's socket and store the messages in the client for further parsing.
* \retval <0 error
* \retval 0 success
*/
static int
sock_read_from_client(ClientSocketMap *clientSocketMap)
{
char buffer[MAXMSG];
int nbytes;
debug(RPT_DEBUG, "%s()", __FUNCTION__);
errno = 0;
nbytes = sock_recv(clientSocketMap->socket, buffer, MAXMSG);
while (nbytes > 0) { /* Data available */
int fr;
char *str;
debug(RPT_DEBUG, "%s: received %4d bytes", __FUNCTION__, nbytes);
/* Append to ring buffer */
sring_write(messageRing, buffer, nbytes);
/* Process all available message in ring buffer */
do {
str = sring_read_string(messageRing);
if (clientSocketMap->client) {
client_add_message(clientSocketMap->client, str);
} else {
report(RPT_DEBUG, "%s: Can't find client %d",
__FUNCTION__, clientSocketMap->socket);
}
} while (str != NULL);
/* Read again, but only as much as space is left */
fr = sring_getMaxWrite(messageRing);
if (fr == 0)
report(RPT_WARNING, "%s: Message buffer full", __FUNCTION__);
nbytes = sock_recv(clientSocketMap->socket, buffer, min(MAXMSG, fr));
}
if (sring_getMaxRead(messageRing) > 0) {
report(RPT_WARNING, "%s: left over bytes in message buffer",
__FUNCTION__);
sring_clear(messageRing);
}
if (nbytes < 0 && errno == EAGAIN)
return 0; /* No data is not an error */
return -1; /* EOF */
}
/* comparison function to find a ClientsocketMap entry by client */
int byClient(void *csm, void *client)
{
return (((ClientSocketMap *) csm)->client == (Client *) client) ? 0 : -1;
}
/** Close an open socket for a given client.
* \param client Client whose socket shall be closed.
* \retval <0 error
* \retval 0 success.
*/
int
sock_destroy_client_socket(Client *client)
{
ClientSocketMap *entry;
LL_Rewind(openSocketList);
entry = LL_Find(openSocketList, byClient, client);
if (entry != NULL) {
sock_destroy_socket();
return 0;
}
return -1;
}
/** Close the socket the openSocketList's \c current pointer points to.
*/
static void
sock_destroy_socket(void)
{
ClientSocketMap *entry = LL_Get(openSocketList);
if (entry != NULL) {
if (entry->client != NULL) {
report(RPT_NOTICE, "Client on socket %i disconnected",
entry->socket);
client_destroy(entry->client);
clients_remove_client(entry->client, PREV);
entry->client = NULL;
}
else {
report(RPT_ERR, "%s: Can't find client of socket %i",
__FUNCTION__, entry->socket);
}
/* close socket and remove it from select()'s mask of active sockets */
FD_CLR(entry->socket, &active_fd_set);
close(entry->socket);
/* re-add socket to the free socket pool */
entry = (ClientSocketMap *) LL_DeleteNode(openSocketList, PREV);
LL_Push(freeClientSocketList, (void*) entry);
}
}
/* return 1 if addr is valid IPv4 */
int verify_ipv4(const char *addr)
{
int result = -1;
if (addr != NULL) {
struct in_addr a;
/* inet_pton returns positive value if it worked */
result = inet_pton(AF_INET, addr, &a);
}
return (result > 0) ? 1 : 0;
}
/* return 1 if addr is valid IPv6 */
int verify_ipv6(const char *addr)
{
int result = 0;
if (addr != NULL) {
struct in6_addr a;
/* inet_pton returns positive value if it worked */
result = inet_pton(AF_INET6, addr, &a);
}
return (result > 0) ? 1 : 0;
}
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