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