lwip/contrib/apps/chargen/chargen.c

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/** @file
*
* chargen server for lwip
*/
/*
* Copyright (c) 2003 NBS Card Technology, Paramus, NJ.
* All rights reserved.
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*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
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*
* Author: David Haas <dhaas@alum.rpi.edu>
*
* Purpose: chargen server for testing and demonstration purposes
*
* This file implements a nice example of handling multiple tcp sockets in a
* server environment. Just call chargen_init() from your application after
* you have initialized lwip and added your network interfaces. Change the
* MAX_SERV option to increase or decrease the number of sessions supported.
*
* chargen will jam as much data as possible into the output socket, so it
* will take up a lot of CPU time. Therefore it will be a good idea to run it
* as the lowest possible priority (just ahead of any idle task).
*
* This is also a good example of how to support multiple sessions in an
* embedded system where you might not have fork().
*/
#include "lwip/opt.h"
#include "lwip/sys.h"
#include "lwip/sockets.h"
#include "lwip/mem.h"
#include <string.h>
#include "chargen.h"
#if LWIP_SOCKET && LWIP_SOCKET_SELECT
#define MAX_SERV 5 /* Maximum number of chargen services. Don't need too many */
#define CHARGEN_THREAD_NAME "chargen"
#define CHARGEN_PRIORITY 254 /* Really low priority */
#define CHARGEN_THREAD_STACKSIZE 0
#define SEND_SIZE TCP_SNDLOWAT /* If we only send this much, then when select
says we can send, we know we won't block */
struct charcb {
struct charcb *next;
int socket;
struct sockaddr_storage cliaddr;
socklen_t clilen;
char nextchar;
};
static struct charcb *charcb_list = 0;
/**************************************************************
* void close_chargen(struct charcb *p_charcb)
*
* Close the socket and remove this charcb from the list.
**************************************************************/
static void
close_chargen(struct charcb *p_charcb)
{
struct charcb *p_search_charcb;
/* Either an error or tcp connection closed on other
* end. Close here */
lwip_close(p_charcb->socket);
/* Free charcb */
if (charcb_list == p_charcb) {
charcb_list = p_charcb->next;
} else {
for (p_search_charcb = charcb_list; p_search_charcb; p_search_charcb = p_search_charcb->next) {
if (p_search_charcb->next == p_charcb) {
p_search_charcb->next = p_charcb->next;
break;
}
}
}
mem_free(p_charcb);
}
/**************************************************************
* void do_read(struct charcb *p_charcb)
*
* Socket definitely is ready for reading. Read a buffer from the socket and
* discard the data. If no data is read, then the socket is closed and the
* charcb is removed from the list and freed.
**************************************************************/
static int
do_read(struct charcb *p_charcb)
{
char buffer[80];
int readcount;
/* Read some data */
readcount = lwip_read(p_charcb->socket, &buffer, 80);
if (readcount <= 0) {
close_chargen(p_charcb);
return -1;
}
return 0;
}
/**************************************************************
* void chargen_thread(void *arg)
*
* chargen task. This server will wait for connections on well
* known TCP port number: 19. For every connection, the server will
* write as much data as possible to the tcp port.
**************************************************************/
static void
chargen_thread(void *arg)
{
int listenfd;
#if LWIP_IPV6
struct sockaddr_in6 chargen_saddr;
#else /* LWIP_IPV6 */
struct sockaddr_in chargen_saddr;
#endif /* LWIP_IPV6 */
fd_set readset;
fd_set writeset;
int i, maxfdp1;
struct charcb *p_charcb;
LWIP_UNUSED_ARG(arg);
memset(&chargen_saddr, 0, sizeof (chargen_saddr));
#if LWIP_IPV6
/* First acquire our socket for listening for connections */
listenfd = lwip_socket(AF_INET6, SOCK_STREAM, 0);
chargen_saddr.sin6_family = AF_INET6;
chargen_saddr.sin6_addr = in6addr_any;
chargen_saddr.sin6_port = lwip_htons(19); /* Chargen server port */
#else /* LWIP_IPV6 */
/* First acquire our socket for listening for connections */
listenfd = lwip_socket(AF_INET, SOCK_STREAM, 0);
chargen_saddr.sin_family = AF_INET;
chargen_saddr.sin_addr.s_addr = PP_HTONL(INADDR_ANY);
chargen_saddr.sin_port = lwip_htons(19); /* Chargen server port */
#endif /* LWIP_IPV6 */
LWIP_ASSERT("chargen_thread(): Socket create failed.", listenfd >= 0);
if (lwip_bind(listenfd, (struct sockaddr *) &chargen_saddr, sizeof (chargen_saddr)) == -1) {
LWIP_ASSERT("chargen_thread(): Socket bind failed.", 0);
}
/* Put socket into listening mode */
if (lwip_listen(listenfd, MAX_SERV) == -1) {
LWIP_ASSERT("chargen_thread(): Listen failed.", 0);
}
/* Wait forever for network input: This could be connections or data */
for (;;) {
maxfdp1 = listenfd + 1;
/* Determine what sockets need to be in readset */
FD_ZERO(&readset);
FD_ZERO(&writeset);
FD_SET(listenfd, &readset);
for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next) {
if (maxfdp1 < p_charcb->socket + 1) {
maxfdp1 = p_charcb->socket + 1;
}
FD_SET(p_charcb->socket, &readset);
FD_SET(p_charcb->socket, &writeset);
}
/* Wait for data or a new connection */
i = lwip_select(maxfdp1, &readset, &writeset, 0, 0);
if (i == 0) {
continue;
}
/* At least one descriptor is ready */
if (FD_ISSET(listenfd, &readset)) {
/* We have a new connection request!!! */
/* Lets create a new control block */
p_charcb = (struct charcb *) mem_malloc(sizeof (struct charcb));
if (p_charcb) {
p_charcb->socket = lwip_accept(listenfd,
(struct sockaddr *) &p_charcb->cliaddr,
&p_charcb->clilen);
if (p_charcb->socket < 0) {
mem_free(p_charcb);
} else {
/* Keep this tecb in our list */
p_charcb->next = charcb_list;
charcb_list = p_charcb;
p_charcb->nextchar = 0x21;
}
} else {
/* No memory to accept connection. Just accept and then close */
int sock;
struct sockaddr cliaddr;
socklen_t clilen;
sock = lwip_accept(listenfd, &cliaddr, &clilen);
if (sock >= 0) {
lwip_close(sock);
}
}
}
/* Go through list of connected clients and process data */
for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next) {
if (FD_ISSET(p_charcb->socket, &readset)) {
/* This socket is ready for reading. This could be because someone typed
* some characters or it could be because the socket is now closed. Try reading
* some data to see. */
if (do_read(p_charcb) < 0) {
break;
}
}
if (FD_ISSET(p_charcb->socket, &writeset)) {
char line[80];
char setchar = p_charcb->nextchar;
for (i = 0; i < 59; i++) {
line[i] = setchar;
if (++setchar == 0x7f) {
setchar = 0x21;
}
}
line[i] = 0;
strcat(line, "\n\r");
if (lwip_write(p_charcb->socket, line, strlen(line)) < 0) {
close_chargen(p_charcb);
break;
}
if (++p_charcb->nextchar == 0x7f) {
p_charcb->nextchar = 0x21;
}
}
}
}
}
/**************************************************************
* void chargen_init(void)
*
* This function initializes the chargen service. This function
* may only be called either before or after tasking has started.
**************************************************************/
void
chargen_init(void)
{
sys_thread_new(CHARGEN_THREAD_NAME, chargen_thread, 0, CHARGEN_THREAD_STACKSIZE, CHARGEN_PRIORITY);
}
#endif /* LWIP_SOCKET && LWIP_SOCKET_SELECT */