1 /*
2 * Copyright (c) 2006-2021, RT-Thread Development Team
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 *
6 * Change Logs:
7 * Date Author Notes
8 */
9
10 #include <rtthread.h>
11 #include <sys/socket.h>
12
13 #ifdef SAL_USING_POSIX
14 #include <sys/select.h> // only dfs_net
15 #include <dfs_file.h>
16 #include <unistd.h>
17 #include <stdio.h>
18 #include <sys/stat.h>
19 #include <sys/statfs.h>
20 #else
21 #define read lwip_read
22 #define write lwip_write
23 #endif /* SAL_USING_POSIX */
24
25 #include "netdb.h"
26
27 #define MAX_SERV 32 /* Maximum number of chargen services. Don't need too many */
28 #define CHARGEN_THREAD_NAME "chargen"
29 #if RT_THREAD_PRIORITY_MAX == 32
30 #define CHARGEN_PRIORITY 20 /* Really low priority */
31 #else
32 #define CHARGEN_PRIORITY 200 /* Really low priority */
33 #endif
34 #define CHARGEN_THREAD_STACKSIZE 1024
35 struct charcb
36 {
37 struct charcb *next;
38 int socket;
39 struct sockaddr_in cliaddr;
40 socklen_t clilen;
41 char nextchar;
42 };
43
44 static struct charcb *charcb_list = 0;
45 static int do_read(struct charcb *p_charcb);
46 static void close_chargen(struct charcb *p_charcb);
47 extern int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);
48
49 /**************************************************************
50 * void chargen_thread(void *arg)
51 *
52 * chargen task. This server will wait for connections on well
53 * known TCP port number: 19. For every connection, the server will
54 * write as much data as possible to the tcp port.
55 **************************************************************/
chargen_thread(void * arg)56 static void chargen_thread(void *arg)
57 {
58 int listenfd;
59 struct sockaddr_in chargen_saddr;
60 fd_set readset;
61 fd_set writeset;
62 int i, maxfdp1;
63 struct charcb *p_charcb;
64
65 /* First acquire our socket for listening for connections */
66 listenfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
67 LWIP_ASSERT("chargen_thread(): Socket create failed.", listenfd >= 0);
68 memset(&chargen_saddr, 0, sizeof(chargen_saddr));
69 chargen_saddr.sin_family = AF_INET;
70 chargen_saddr.sin_addr.s_addr = htonl(INADDR_ANY);
71 chargen_saddr.sin_port = htons(19); // Chargen server port
72
73 if (bind(listenfd, (struct sockaddr *) &chargen_saddr, sizeof(chargen_saddr)) == -1)
74 LWIP_ASSERT("chargen_thread(): Socket bind failed.", 0);
75
76 /* Put socket into listening mode */
77 if (listen(listenfd, MAX_SERV) == -1)
78 LWIP_ASSERT("chargen_thread(): Listen failed.", 0);
79
80
81 /* Wait forever for network input: This could be connections or data */
82 for (;;)
83 {
84 maxfdp1 = listenfd + 1;
85
86 /* Determine what sockets need to be in readset */
87 FD_ZERO(&readset);
88 FD_ZERO(&writeset);
89 FD_SET(listenfd, &readset);
90 for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next)
91 {
92 if (maxfdp1 < p_charcb->socket + 1)
93 maxfdp1 = p_charcb->socket + 1;
94 FD_SET(p_charcb->socket, &readset);
95 FD_SET(p_charcb->socket, &writeset);
96 }
97
98 /* Wait for data or a new connection */
99 i = select(maxfdp1, &readset, &writeset, 0, 0);
100
101 if (i == 0) continue;
102
103 /* At least one descriptor is ready */
104 if (FD_ISSET(listenfd, &readset))
105 {
106 /* We have a new connection request!!! */
107 /* Lets create a new control block */
108 p_charcb = (struct charcb *)rt_calloc(1, sizeof(struct charcb));
109 if (p_charcb)
110 {
111 p_charcb->socket = accept(listenfd,
112 (struct sockaddr *) &p_charcb->cliaddr,
113 &p_charcb->clilen);
114 if (p_charcb->socket < 0)
115 rt_free(p_charcb);
116 else
117 {
118 /* Keep this tecb in our list */
119 p_charcb->next = charcb_list;
120 charcb_list = p_charcb;
121 p_charcb->nextchar = 0x21;
122 }
123 }
124 else
125 {
126 /* No memory to accept connection. Just accept and then close */
127 int sock;
128 struct sockaddr cliaddr;
129 socklen_t clilen;
130
131 sock = accept(listenfd, &cliaddr, &clilen);
132 if (sock >= 0)
133 closesocket(sock);
134 }
135 }
136
137 /* Go through list of connected clients and process data */
138 for (p_charcb = charcb_list; p_charcb; p_charcb = p_charcb->next)
139 {
140 if (FD_ISSET(p_charcb->socket, &readset))
141 {
142 /* This socket is ready for reading. This could be because someone typed
143 * some characters or it could be because the socket is now closed. Try reading
144 * some data to see. */
145 if (do_read(p_charcb) < 0)
146 break;
147 }
148
149 if (FD_ISSET(p_charcb->socket, &writeset))
150 {
151 char line[80];
152 char setchar = p_charcb->nextchar;
153
154 for (i = 0; i < 59; i++)
155 {
156 line[i] = setchar;
157 if (++setchar == 0x7f)
158 setchar = 0x21;
159 }
160
161 line[i] = 0;
162 strcat(line, "\n\r");
163 if (write(p_charcb->socket, line, strlen(line)) < 0)
164 {
165 close_chargen(p_charcb);
166 break;
167 }
168
169 if (++p_charcb->nextchar == 0x7f)
170 p_charcb->nextchar = 0x21;
171 }
172 }
173 }
174 }
175
176 /**************************************************************
177 * void close_chargen(struct charcb *p_charcb)
178 *
179 * Close the socket and remove this charcb from the list.
180 **************************************************************/
close_chargen(struct charcb * p_charcb)181 static void close_chargen(struct charcb *p_charcb)
182 {
183 struct charcb *p_search_charcb;
184
185 /* Either an error or tcp connection closed on other
186 * end. Close here */
187 closesocket(p_charcb->socket);
188
189 /* Free charcb */
190 if (charcb_list == p_charcb)
191 charcb_list = p_charcb->next;
192 else
193 for (p_search_charcb = charcb_list; p_search_charcb; p_search_charcb = p_search_charcb->next)
194 {
195 if (p_search_charcb->next == p_charcb)
196 {
197 p_search_charcb->next = p_charcb->next;
198 break;
199 }
200 }
201
202 rt_free(p_charcb);
203 }
204
205 /**************************************************************
206 * void do_read(struct charcb *p_charcb)
207 *
208 * Socket definitely is ready for reading. Read a buffer from the socket and
209 * discard the data. If no data is read, then the socket is closed and the
210 * charcb is removed from the list and freed.
211 **************************************************************/
do_read(struct charcb * p_charcb)212 static int do_read(struct charcb *p_charcb)
213 {
214 char buffer[80];
215 int readcount;
216
217 /* Read some data */
218 readcount = read(p_charcb->socket, &buffer, 80);
219 if (readcount <= 0)
220 {
221 close_chargen(p_charcb);
222 return -1;
223 }
224 return 0;
225 }
226
chargen_init(void)227 void chargen_init(void)
228 {
229 rt_thread_t chargen;
230
231 chargen = rt_thread_create(CHARGEN_THREAD_NAME,
232 chargen_thread, RT_NULL,
233 CHARGEN_THREAD_STACKSIZE,
234 CHARGEN_PRIORITY, 5);
235 if (chargen != RT_NULL) rt_thread_startup(chargen);
236 }
237 #ifdef RT_USING_FINSH
238 #include <finsh.h>
chargen()239 void chargen()
240 {
241 chargen_init();
242 }
243 FINSH_FUNCTION_EXPORT(chargen, start chargen server);
244 #endif
245