1 /*
2 * libwebsockets - small server side websockets and web server implementation
3 *
4 * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 */
24
25 #include "private-lib-core.h"
26
27 int
lws_plat_pipe_create(struct lws * wsi)28 lws_plat_pipe_create(struct lws *wsi)
29 {
30 struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
31 struct sockaddr_in *si = &wsi->context->frt_pipe_si;
32 lws_sockfd_type *fd = pt->dummy_pipe_fds;
33
34 /*
35 * There's no pipe abstraction on lwip / freertos... use a UDP socket
36 * listening on 127.0.0.1:54321 and send a byte to it from a second UDP
37 * socket to cancel the wait.
38 */
39
40 fd[0] = socket(AF_INET, SOCK_DGRAM, 0);
41 if (fd[0] < 0)
42 goto bail;
43
44 fd[1] = socket(AF_INET, SOCK_DGRAM, 0);
45 if (fd[1] < 0)
46 goto bail;
47
48 /*
49 * No need for memset since it's in zalloc'd context... it's in the
50 * context so we can reuse the prepared sockaddr to send tp fd[0] whem
51 * we want to cancel the wait
52 */
53
54 si->sin_family = AF_INET;
55 si->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
56 si->sin_port = htons(54321);
57
58 if (bind(fd[0], (const struct sockaddr *)si, sizeof(*si)) < 0)
59 goto bail;
60
61 return 0;
62
63 bail:
64 lwsl_err("%s: failed\n", __func__);
65
66 return 1;
67 }
68
69 int
lws_plat_pipe_signal(struct lws * wsi)70 lws_plat_pipe_signal(struct lws *wsi)
71 {
72 struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
73 struct sockaddr_in *si = &wsi->context->frt_pipe_si;
74 lws_sockfd_type *fd = pt->dummy_pipe_fds;
75 uint8_t u = 0;
76 int n;
77
78 /*
79 * Send a single UDP byte payload to the listening socket fd[0], forcing
80 * the event loop wait to wake. fd[1] and context->frt_pipe_si are
81 * set at context creation and are static, the UDP sendto is supposed to
82 * be threadsafe for lwip:
83 *
84 * https://lwip.fandom.com/wiki/LwIP_and_multithreading
85 *
86 * Sockets generally can't be used by more than one application thread
87 * (on udp/raw netconn, doing a sendto/recv is currently possible).
88 */
89
90 n = sendto(fd[1], &u, 1, 0, (struct sockaddr *)si, sizeof(*si));
91
92 return n != 1;
93 }
94
95 void
lws_plat_pipe_close(struct lws * wsi)96 lws_plat_pipe_close(struct lws *wsi)
97 {
98 struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
99 lws_sockfd_type *fd = pt->dummy_pipe_fds;
100
101 if (fd[0] && fd[0] != -1)
102 close(fd[0]);
103 if (fd[1] && fd[1] != -1)
104 close(fd[1]);
105
106 fd[0] = fd[1] = -1;
107 }
108