1 /** @file
2 *
3 * chargen server for lwip
4 */
5 /*
6 * Copyright (c) 2003 NBS Card Technology, Paramus, NJ.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without modification,
10 * are permitted provided that the following conditions are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright notice,
15 * this list of conditions and the following disclaimer in the documentation
16 * and/or other materials provided with the distribution.
17 * 3. The name of the author may not be used to endorse or promote products
18 * derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
21 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
23 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
25 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
28 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
29 * OF SUCH DAMAGE.
30 *
31 * This file is part of the lwIP TCP/IP stack.
32 *
33 * Author: David Haas <dhaas@alum.rpi.edu>
34 *
35 * Purpose: chargen server for testing and demonstration purposes
36 *
37 * This file implements a nice example of handling multiple tcp sockets in a
38 * server environment. Just call chargen_init() from your application after
39 * you have initialized lwip and added your network interfaces. Change the
40 * MAX_SERV option to increase or decrease the number of sessions supported.
41 *
42 * chargen will jam as much data as possible into the output socket, so it
43 * will take up a lot of CPU time. Therefore it will be a good idea to run it
44 * as the lowest possible priority (just ahead of any idle task).
45 *
46 * This is also a good example of how to support multiple sessions in an
47 * embedded system where you might not have fork().
48 */
49
50 #include "lwip/opt.h"
51 #include "lwip/sys.h"
52 #include "lwip/sockets.h"
53 #include "lwip/mem.h"
54
55 #include <string.h>
56
57 #include "chargen.h"
58
59 #if LWIP_SOCKET && LWIP_SOCKET_SELECT
60
61 #define MAX_SERV 5 /* Maximum number of chargen services. Don't need too many */
62 #define CHARGEN_THREAD_NAME "chargen"
63 #define CHARGEN_PRIORITY 254 /* Really low priority */
64 #define CHARGEN_THREAD_STACKSIZE 0
65 #define SEND_SIZE TCP_SNDLOWAT /* If we only send this much, then when select
66 says we can send, we know we won't block */
67
68 struct charcb {
69 struct charcb *next;
70 int socket;
71 struct sockaddr_storage cliaddr;
72 socklen_t clilen;
73 char nextchar;
74 };
75
76 static struct charcb *charcb_list = NULL;
77
78 /**************************************************************
79 * void close_chargen(struct charcb *p_charcb)
80 *
81 * Close the socket and remove this charcb from the list.
82 **************************************************************/
83 static void
close_chargen(struct charcb * p_charcb)84 close_chargen(struct charcb *p_charcb)
85 {
86 struct charcb *p_search_charcb;
87
88 /* Either an error or tcp connection closed on other
89 * end. Close here */
90 lwip_close(p_charcb->socket);
91 /* Free charcb */
92 if (charcb_list == p_charcb) {
93 charcb_list = p_charcb->next;
94 } else {
95 for (p_search_charcb = charcb_list; p_search_charcb; p_search_charcb = p_search_charcb->next) {
96 if (p_search_charcb->next == p_charcb) {
97 p_search_charcb->next = p_charcb->next;
98 break;
99 }
100 }
101 }
102 mem_free(p_charcb);
103 }
104
105 /**************************************************************
106 * void do_read(struct charcb *p_charcb)
107 *
108 * Socket definitely is ready for reading. Read a buffer from the socket and
109 * discard the data. If no data is read, then the socket is closed and the
110 * charcb is removed from the list and freed.
111 **************************************************************/
112 static int
do_read(struct charcb * p_charcb)113 do_read(struct charcb *p_charcb)
114 {
115 char buffer[80];
116 int readcount;
117
118 /* Read some data */
119 readcount = lwip_read(p_charcb->socket, &buffer, 80);
120 if (readcount <= 0) {
121 close_chargen(p_charcb);
122 return -1;
123 }
124 return 0;
125 }
126
127 /**************************************************************
128 * void chargen_thread(void *arg)
129 *
130 * chargen task. This server will wait for connections on well
131 * known TCP port number: 19. For every connection, the server will
132 * write as much data as possible to the tcp port.
133 **************************************************************/
134 static void
chargen_thread(void * arg)135 chargen_thread(void *arg)
136 {
137 int listenfd;
138 #if LWIP_IPV6
139 struct sockaddr_in6 chargen_saddr;
140 #else /* LWIP_IPV6 */
141 struct sockaddr_in chargen_saddr;
142 #endif /* LWIP_IPV6 */
143 fd_set readset;
144 fd_set writeset;
145 int i, maxfdp1;
146 struct charcb *p_charcb;
147 LWIP_UNUSED_ARG(arg);
148
149 memset(&chargen_saddr, 0, sizeof (chargen_saddr));
150 #if LWIP_IPV6
151 /* First acquire our socket for listening for connections */
152 listenfd = lwip_socket(AF_INET6, SOCK_STREAM, 0);
153 chargen_saddr.sin6_family = AF_INET6;
154 chargen_saddr.sin6_addr = in6addr_any;
155 chargen_saddr.sin6_port = lwip_htons(19); /* Chargen server port */
156 #else /* LWIP_IPV6 */
157 /* First acquire our socket for listening for connections */
158 listenfd = lwip_socket(AF_INET, SOCK_STREAM, 0);
159 chargen_saddr.sin_family = AF_INET;
160 chargen_saddr.sin_addr.s_addr = PP_HTONL(INADDR_ANY);
161 chargen_saddr.sin_port = lwip_htons(19); /* Chargen server port */
162 #endif /* LWIP_IPV6 */
163
164 LWIP_ASSERT("chargen_thread(): Socket create failed.", listenfd >= 0);
165
166 if (lwip_bind(listenfd, (struct sockaddr *) &chargen_saddr, sizeof (chargen_saddr)) == -1) {
167 LWIP_ASSERT("chargen_thread(): Socket bind failed.", 0);
168 }
169
170 /* Put socket into listening mode */
171 if (lwip_listen(listenfd, MAX_SERV) == -1) {
172 LWIP_ASSERT("chargen_thread(): Listen failed.", 0);
173 }
174
175
176 /* Wait forever for network input: This could be connections or data */
177 for (;;) {
178 maxfdp1 = listenfd + 1;
179
180 /* Determine what sockets need to be in readset */
181 FD_ZERO(&readset);
182 FD_ZERO(&writeset);
183 FD_SET(listenfd, &readset);
184 for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next) {
185 if (maxfdp1 < p_charcb->socket + 1) {
186 maxfdp1 = p_charcb->socket + 1;
187 }
188 FD_SET(p_charcb->socket, &readset);
189 FD_SET(p_charcb->socket, &writeset);
190 }
191
192 /* Wait for data or a new connection */
193 i = lwip_select(maxfdp1, &readset, &writeset, NULL, NULL);
194
195 if (i == 0) {
196 continue;
197 }
198 /* At least one descriptor is ready */
199 if (FD_ISSET(listenfd, &readset)) {
200 /* We have a new connection request!!! */
201 /* Lets create a new control block */
202 p_charcb = (struct charcb *) mem_malloc(sizeof (struct charcb));
203 if (p_charcb) {
204 p_charcb->socket = lwip_accept(listenfd,
205 (struct sockaddr *) &p_charcb->cliaddr,
206 &p_charcb->clilen);
207 if (p_charcb->socket < 0) {
208 mem_free(p_charcb);
209 } else {
210 /* Keep this tecb in our list */
211 p_charcb->next = charcb_list;
212 charcb_list = p_charcb;
213 p_charcb->nextchar = 0x21;
214 }
215 } else {
216 /* No memory to accept connection. Just accept and then close */
217 int sock;
218 struct sockaddr cliaddr;
219 socklen_t clilen;
220
221 sock = lwip_accept(listenfd, &cliaddr, &clilen);
222 if (sock >= 0) {
223 lwip_close(sock);
224 }
225 }
226 }
227 /* Go through list of connected clients and process data */
228 for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next) {
229 if (FD_ISSET(p_charcb->socket, &readset)) {
230 /* This socket is ready for reading. This could be because someone typed
231 * some characters or it could be because the socket is now closed. Try reading
232 * some data to see. */
233 if (do_read(p_charcb) < 0) {
234 break;
235 }
236 }
237 if (FD_ISSET(p_charcb->socket, &writeset)) {
238 char line[80];
239 char setchar = p_charcb->nextchar;
240
241 for (i = 0; i < 59; i++) {
242 line[i] = setchar;
243 if (++setchar == 0x7f) {
244 setchar = 0x21;
245 }
246 }
247 line[i] = 0;
248 strcat(line, "\n\r");
249 if (lwip_write(p_charcb->socket, line, strlen(line)) < 0) {
250 close_chargen(p_charcb);
251 break;
252 }
253 if (++p_charcb->nextchar == 0x7f) {
254 p_charcb->nextchar = 0x21;
255 }
256 }
257 }
258 }
259 }
260
261
262 /**************************************************************
263 * void chargen_init(void)
264 *
265 * This function initializes the chargen service. This function
266 * may only be called either before or after tasking has started.
267 **************************************************************/
268 void
chargen_init(void)269 chargen_init(void)
270 {
271 sys_thread_new(CHARGEN_THREAD_NAME, chargen_thread, NULL, CHARGEN_THREAD_STACKSIZE, CHARGEN_PRIORITY);
272 }
273
274 #endif /* LWIP_SOCKET && LWIP_SOCKET_SELECT */
275