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1 | /* |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2023 Gerhard Sittig <gerhard.sittig@gmx.net> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include "config.h" | |
21 | ||
22 | #include <libsigrok/libsigrok.h> | |
23 | #include <string.h> | |
24 | ||
25 | #include "libsigrok-internal.h" | |
26 | ||
27 | #define LOG_PREFIX "serial-tcpraw" | |
28 | ||
29 | #define SER_TCPRAW_CONN_PREFIX "tcp-raw" | |
30 | ||
31 | /** | |
32 | * @file | |
33 | * | |
34 | * Serial port handling, raw TCP support. | |
35 | */ | |
36 | ||
37 | /** | |
38 | * @defgroup grp_serial_tcpraw Serial port handling, raw TCP group | |
39 | * | |
40 | * Disguise raw byte sequences over TCP sockets as a serial transport. | |
41 | * | |
42 | * @{ | |
43 | */ | |
44 | ||
45 | /* {{{ TCP specific helper routines */ | |
46 | ||
47 | /** | |
48 | * Parse conn= specs for serial over TCP communication. | |
49 | * | |
50 | * @param[in] serial The serial port that is about to get opened. | |
51 | * @param[in] spec The caller provided conn= specification. | |
52 | * @param[out] host_ref Pointer to host name or IP addr (text string). | |
53 | * @param[out] port_ref Pointer to a TCP port (text string). | |
54 | * | |
55 | * @return 0 upon success, non-zero upon failure. Fills the *_ref output | |
56 | * values. | |
57 | * | |
58 | * Summary of parsing rules as they are implemented: | |
59 | * - The 'spec' MUST start with "tcp-raw" followed by a separator. The | |
60 | * prefix alone is not sufficient, host address and port number are | |
61 | * mandatory. | |
62 | * - Host name follows. It's a DNS name or an IP address. | |
63 | * - TCP port follows. Can be a number or a "service" name. | |
64 | * - More than three fields are accepted, but currently don't take any | |
65 | * effect. It's yet to be seen whether "options" or "variants" are | |
66 | * needed or desired. For now any trailing fields are ignored. Cisco | |
67 | * style serial-over-TCP as seen in ser2net(1) comes to mind (which | |
68 | * includes configuration and control beyond data transmission). But | |
69 | * its spec is rather involved, and ser2net can already derive COM | |
70 | * port configurations from TCP port numbers, so it's not a blocker. | |
71 | * That variant probably should go under a different name anyway. | |
72 | * | |
73 | * Supported format resulting from these rules: | |
74 | * tcp-raw/<ipaddr>/<port> | |
75 | */ | |
76 | static int ser_tcpraw_parse_conn_spec( | |
77 | struct sr_serial_dev_inst *serial, const char *spec, | |
78 | char **host_ref, char **port_ref) | |
79 | { | |
80 | char **fields; | |
81 | size_t count; | |
82 | gboolean valid; | |
83 | char *host, *port; | |
84 | ||
85 | if (host_ref) | |
86 | *host_ref = NULL; | |
87 | if (port_ref) | |
88 | *port_ref = NULL; | |
89 | ||
90 | host = NULL; | |
91 | port = NULL; | |
92 | if (!serial || !spec || !*spec) | |
93 | return SR_ERR_ARG; | |
94 | ||
95 | fields = g_strsplit(spec, "/", 0); | |
96 | if (!fields) | |
97 | return SR_ERR_ARG; | |
98 | count = g_strv_length(fields); | |
99 | ||
100 | valid = TRUE; | |
101 | if (count < 3) | |
102 | valid = FALSE; | |
103 | if (valid && strcmp(fields[0], SER_TCPRAW_CONN_PREFIX) != 0) | |
104 | valid = FALSE; | |
105 | if (valid) { | |
106 | host = fields[1]; | |
107 | if (!host || !*host) | |
108 | valid = FALSE; | |
109 | } | |
110 | if (valid) { | |
111 | port = fields[2]; | |
112 | if (!port || !*port) | |
113 | valid = FALSE; | |
114 | } | |
115 | /* Silently ignore trailing fields. Could be future options. */ | |
116 | if (count > 3) | |
117 | sr_warn("Ignoring excess parameters in %s.", spec); | |
118 | ||
119 | if (valid) { | |
120 | if (host_ref && host) | |
121 | *host_ref = g_strdup(host); | |
122 | if (port_ref && port) | |
123 | *port_ref = g_strdup(port); | |
124 | } | |
125 | g_strfreev(fields); | |
126 | return valid ? SR_OK : SR_ERR_ARG; | |
127 | } | |
128 | ||
129 | /* }}} */ | |
130 | /* {{{ transport methods called by the common serial.c code */ | |
131 | ||
132 | /* See if a serial port's name refers to a raw TCP connection. */ | |
133 | SR_PRIV int ser_name_is_tcpraw(struct sr_serial_dev_inst *serial) | |
134 | { | |
135 | char *p; | |
136 | ||
137 | if (!serial) | |
138 | return 0; | |
139 | if (!serial->port || !*serial->port) | |
140 | return 0; | |
141 | ||
142 | p = serial->port; | |
143 | if (!g_str_has_prefix(p, SER_TCPRAW_CONN_PREFIX)) | |
144 | return 0; | |
145 | p += strlen(SER_TCPRAW_CONN_PREFIX); | |
146 | if (*p != '/') | |
147 | return 0; | |
148 | ||
149 | return 1; | |
150 | } | |
151 | ||
152 | static int ser_tcpraw_open(struct sr_serial_dev_inst *serial, int flags) | |
153 | { | |
154 | char *host, *port; | |
155 | int ret; | |
156 | ||
157 | (void)flags; | |
158 | ||
159 | ret = ser_tcpraw_parse_conn_spec(serial, serial->port, | |
160 | &host, &port); | |
161 | if (ret != SR_OK) { | |
162 | g_free(host); | |
163 | g_free(port); | |
164 | return SR_ERR_ARG; | |
165 | } | |
166 | serial->tcp_dev = sr_tcp_dev_inst_new(host, port); | |
167 | g_free(host); | |
168 | g_free(port); | |
169 | if (!serial->tcp_dev) | |
170 | return SR_ERR_MALLOC; | |
171 | ||
172 | /* | |
173 | * Open the TCP socket. Only keep caller's parameters (and the | |
174 | * resulting socket fd) when open completes successfully. | |
175 | */ | |
176 | ret = sr_tcp_connect(serial->tcp_dev); | |
177 | if (ret != SR_OK) { | |
178 | sr_err("Failed to establish TCP connection."); | |
179 | sr_tcp_dev_inst_free(serial->tcp_dev); | |
180 | serial->tcp_dev = NULL; | |
181 | return SR_ERR_IO; | |
182 | } | |
183 | ||
184 | return SR_OK; | |
185 | } | |
186 | ||
187 | static int ser_tcpraw_close(struct sr_serial_dev_inst *serial) | |
188 | { | |
189 | ||
190 | if (!serial) | |
191 | return SR_ERR_ARG; | |
192 | ||
193 | if (!serial->tcp_dev) | |
194 | return SR_OK; | |
195 | ||
196 | (void)sr_tcp_disconnect(serial->tcp_dev); | |
197 | return SR_OK; | |
198 | } | |
199 | ||
200 | static int ser_tcpraw_setup_source_add(struct sr_session *session, | |
201 | struct sr_serial_dev_inst *serial, int events, int timeout, | |
202 | sr_receive_data_callback cb, void *cb_data) | |
203 | { | |
204 | if (!serial || !serial->tcp_dev) | |
205 | return SR_ERR_ARG; | |
206 | return sr_tcp_source_add(session, serial->tcp_dev, | |
207 | events, timeout, cb, cb_data); | |
208 | } | |
209 | ||
210 | static int ser_tcpraw_setup_source_remove(struct sr_session *session, | |
211 | struct sr_serial_dev_inst *serial) | |
212 | { | |
213 | if (!serial || !serial->tcp_dev) | |
214 | return SR_ERR_ARG; | |
215 | (void)sr_tcp_source_remove(session, serial->tcp_dev); | |
216 | return SR_OK; | |
217 | } | |
218 | ||
219 | static int ser_tcpraw_write(struct sr_serial_dev_inst *serial, | |
220 | const void *buf, size_t count, | |
221 | int nonblocking, unsigned int timeout_ms) | |
222 | { | |
223 | size_t total, written; | |
224 | ssize_t ret; | |
225 | ||
226 | /* Non-blocking writes, and write timeouts, are not supported. */ | |
227 | (void)nonblocking; | |
228 | (void)timeout_ms; | |
229 | ||
230 | if (!serial || !serial->tcp_dev) | |
231 | return SR_ERR_ARG; | |
232 | ||
233 | total = 0; | |
234 | while (count) { | |
235 | ret = sr_tcp_write_bytes(serial->tcp_dev, buf, count); | |
236 | if (ret < 0 && !total) { | |
237 | sr_err("Error sending TCP transmit data."); | |
238 | return total; | |
239 | } | |
240 | if (ret <= 0) { | |
241 | count += total; | |
242 | sr_warn("Short transmission of TCP data (%zu/%zu).", | |
243 | total, count); | |
244 | return total; | |
245 | } | |
246 | written = (size_t)ret; | |
247 | buf += written; | |
248 | count -= written; | |
249 | total += written; | |
250 | } | |
251 | ||
252 | return total; | |
253 | } | |
254 | ||
255 | static int ser_tcpraw_read(struct sr_serial_dev_inst *serial, | |
256 | void *buf, size_t count, | |
257 | int nonblocking, unsigned int timeout_ms) | |
258 | { | |
259 | guint64 deadline_us, now_us; | |
260 | size_t total, chunk; | |
261 | ssize_t ret; | |
262 | ||
263 | if (!serial || !serial->tcp_dev) | |
264 | return SR_ERR_ARG; | |
265 | if (!count) | |
266 | return 0; | |
267 | ||
268 | /* | |
269 | * Timeouts are only useful in blocking mode, non-blocking read | |
270 | * will return as soon as an iteration sees no more data. | |
271 | * Silence a (false) compiler warning, always assign to 'now_us'. | |
272 | */ | |
273 | if (nonblocking) | |
274 | timeout_ms = 0; | |
275 | deadline_us = now_us = 0; | |
276 | if (timeout_ms) { | |
277 | now_us = g_get_monotonic_time(); | |
278 | deadline_us = now_us + timeout_ms * 1000; | |
279 | } | |
280 | ||
281 | /* | |
282 | * Keep reading until the caller's requested length is reached, | |
283 | * or fatal errors are seen, or specified timeouts have expired. | |
284 | */ | |
285 | total = 0; | |
286 | while (count) { | |
287 | ret = sr_tcp_read_bytes(serial->tcp_dev, | |
288 | buf, count, nonblocking); | |
289 | if (ret < 0 && !total) { | |
290 | sr_err("Failed to receive TCP data."); | |
291 | break; | |
292 | } | |
293 | if (ret < 0) { | |
294 | /* Short read, not worth warning about. */ | |
295 | break; | |
296 | } | |
297 | if (ret == 0 && nonblocking) | |
298 | break; | |
299 | if (ret == 0 && deadline_us) { | |
300 | now_us = g_get_monotonic_time(); | |
301 | if (now_us >= deadline_us) | |
302 | break; | |
303 | g_usleep(10 * 1000); | |
304 | continue; | |
305 | } | |
306 | chunk = (size_t)ret; | |
307 | buf += chunk; | |
308 | count -= chunk; | |
309 | total += chunk; | |
310 | } | |
311 | ||
312 | return total; | |
313 | } | |
314 | ||
315 | static struct ser_lib_functions serlib_tcpraw = { | |
316 | .open = ser_tcpraw_open, | |
317 | .close = ser_tcpraw_close, | |
318 | .write = ser_tcpraw_write, | |
319 | .read = ser_tcpraw_read, | |
320 | .set_params = std_dummy_set_params, | |
321 | .set_handshake = std_dummy_set_handshake, | |
322 | .setup_source_add = ser_tcpraw_setup_source_add, | |
323 | .setup_source_remove = ser_tcpraw_setup_source_remove, | |
324 | .get_frame_format = NULL, | |
325 | }; | |
326 | SR_PRIV struct ser_lib_functions *ser_lib_funcs_tcpraw = &serlib_tcpraw; | |
327 | ||
328 | /** @} */ |