9de618b2c2f018f428684f658626a1a6e5d00916
[paraslash.git] / dccp_send.c
1 /*
2 * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file dccp_send.c paraslash's dccp sender */
8
9 /*
10 * based on server.c of dccp-cs-0.01.tar.bz2,
11 * (C) 2005 Ian McDonald <imcdnzl@gmail.com>
12 */
13
14 #include <sys/types.h>
15 #include <dirent.h>
16
17 #include "para.h"
18 #include "error.h"
19 #include "string.h"
20 #include "afh.h"
21 #include "afs.h"
22 #include "server.h"
23 #include "net.h"
24 #include "list.h"
25 #include "vss.h"
26 #include "send.h"
27 #include "fd.h"
28 #include "close_on_fork.h"
29 #include "chunk_queue.h"
30 #include "server.cmdline.h"
31
32 /** the list of connected clients **/
33 static struct list_head clients;
34 static int listen_fd = -1;
35 static struct sender *self;
36
37 /** Maximal number of bytes in a chunk queue. */
38 #define DCCP_MAX_PENDING_BYTES 40000
39
40 /** describes one connected client */
41 struct dccp_client {
42 /** the dccp socket */
43 int fd;
44 /** The socket `name' of the client. */
45 char *name;
46 /** the position of this client in the client list */
47 struct list_head node;
48 /** non-zero if audio file header has been sent */
49 int header_sent;
50 /** The list of pending chunks for this client. */
51 struct chunk_queue *cq;
52 };
53
54 static void dccp_pre_select( int *max_fileno, fd_set *rfds,
55 __a_unused fd_set *wfds)
56 {
57 if (listen_fd < 0)
58 return;
59 FD_SET(listen_fd, rfds);
60 *max_fileno = PARA_MAX(*max_fileno, listen_fd);
61 }
62
63 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
64 {
65 struct dccp_client *dc;
66 int ret;
67
68 if (listen_fd < 0 || !FD_ISSET(listen_fd, rfds))
69 return;
70 ret = para_accept(listen_fd, NULL, 0);
71 if (ret < 0) {
72 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
73 return;
74 }
75 /*
76 * Bypass unused CCID paths: the sender does not receive application data
77 * from the client; by shutting down this unused communication path we can
78 * reduce processing costs a bit. See analogous comment in dccp_recv.c.
79 */
80 if (shutdown(ret, SHUT_RD) < 0) {
81 PARA_ERROR_LOG("shutdown(SHUT_RD): %s\n", strerror(errno));
82 return;
83 }
84 dc = para_calloc(sizeof(struct dccp_client));
85 dc->fd = ret;
86 dc->name = make_message("%s", remote_name(dc->fd));
87 PARA_NOTICE_LOG("connection from %s\n", dc->name);
88 para_list_add(&dc->node, &clients);
89 add_close_on_fork_list(dc->fd);
90 mark_fd_nonblocking(dc->fd);
91 dc->cq = cq_new(DCCP_MAX_PENDING_BYTES);
92 }
93
94 static int dccp_open(void)
95 {
96 int ret = para_listen(AF_UNSPEC, IPPROTO_DCCP, conf.dccp_port_arg);
97
98 if (ret < 0)
99 return ret;
100 listen_fd = ret;
101 ret = mark_fd_nonblocking(listen_fd);
102 if (ret < 0) {
103 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
104 exit(EXIT_FAILURE);
105 }
106 add_close_on_fork_list(listen_fd);
107 return 1;
108 }
109
110 static void dccp_shutdown_client(struct dccp_client *dc)
111 {
112 PARA_DEBUG_LOG("shutting down %s (fd %d)\n", dc->name, dc->fd);
113 free(dc->name);
114 close(dc->fd);
115 del_close_on_fork_list(dc->fd);
116 cq_destroy(dc->cq);
117 list_del(&dc->node);
118 free(dc);
119 }
120
121 /*
122 * ret: Negative on errors, zero if nothing was written and write returned
123 * EAGAIN, number of bytes written else.
124 */
125 static int dccp_write(int fd, const char *buf, size_t len)
126 {
127 size_t written = 0;
128 int ret = 0;
129
130 while (written < len) {
131 ret = write(fd, buf + written, PARA_MIN(1024, len - written));
132 /*
133 * Error handling: CCID3 has a sending wait queue which fills up and is
134 * emptied asynchronously. The EAGAIN case means that there is currently
135 * no space in the wait queue, but this can change at any moment and is
136 * thus not an error condition.
137 */
138 if (ret < 0 && errno == EAGAIN)
139 return written;
140 if (ret < 0) {
141 PARA_ERROR_LOG("%s\n", strerror(errno));
142 return -E_DCCP_WRITE;
143 }
144 written += ret;
145 }
146 return written;
147 }
148
149 static int queue_chunk_or_shutdown(struct dccp_client *dc, long unsigned chunk_num,
150 size_t sent)
151 {
152 int ret = cq_enqueue(dc->cq, chunk_num, sent);
153 if (ret < 0) {
154 PARA_NOTICE_LOG("enqueue error\n");
155 dccp_shutdown_client(dc);
156 }
157 return ret;
158 }
159
160 static int send_queued_chunks(struct dccp_client *dc)
161 {
162 struct queued_chunk *qc;
163 while ((qc = cq_peek(dc->cq))) {
164 char *buf;
165 size_t len;
166 int ret;
167 cq_get(qc, &buf, &len);
168 ret = dccp_write(dc->fd, buf, len);
169 if (ret < 0)
170 return ret;
171 cq_update(dc->cq, ret);
172 if (ret != len)
173 return 1;
174 cq_dequeue(dc->cq);
175 }
176 return 1;
177 }
178
179 static void dccp_send(long unsigned current_chunk,
180 __a_unused long unsigned chunks_sent, const char *buf, size_t len)
181 {
182 struct dccp_client *dc, *tmp;
183 int ret;
184 char *header_buf;
185 size_t header_len;
186
187 if (listen_fd < 0 || !len)
188 return;
189
190 list_for_each_entry_safe(dc, tmp, &clients, node) {
191 if (!dc->header_sent && current_chunk) {
192 header_buf = vss_get_header(&header_len);
193 if (header_buf && header_len > 0) {
194 if (queue_chunk_or_shutdown(dc, -1U, 0) < 0)
195 continue;
196 }
197 dc->header_sent = 1;
198 }
199 ret = send_queued_chunks(dc);
200 if (ret < 0) {
201 dccp_shutdown_client(dc);
202 continue;
203 }
204 // PARA_DEBUG_LOG("writing %d bytes to fd %d\n", len, dc->fd);
205 ret = dccp_write(dc->fd, buf, len);
206 if (ret < 0) {
207 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
208 dccp_shutdown_client(dc);
209 continue;
210 }
211 if (ret != len)
212 queue_chunk_or_shutdown(dc, current_chunk, ret);
213 }
214 }
215
216 static void dccp_shutdown_clients(void)
217 {
218 struct dccp_client *dc, *tmp;
219
220 list_for_each_entry_safe(dc, tmp, &clients, node)
221 dccp_shutdown_client(dc);
222 }
223
224 static char *dccp_info(void)
225 {
226 static char *buf;
227 int num_clients = 0;
228 struct dccp_client *dc, *tmp;
229
230 free(buf);
231 list_for_each_entry_safe(dc, tmp, &clients, node)
232 num_clients++;
233 buf = make_message("dccp connected clients: %d\n", num_clients);
234 return buf;
235 }
236
237 static char *dccp_help(void)
238 {
239 return make_message("no help available\n");
240 }
241
242 /**
243 * the init function of the dccp sender
244 *
245 * \param s pointer to the dccp sender struct
246 *
247 * It initializes all function pointers of \a s and starts
248 * listening on the given port.
249 */
250 void dccp_send_init(struct sender *s)
251 {
252 int ret;
253
254 INIT_LIST_HEAD(&clients);
255 s->info = dccp_info;
256 s->send = dccp_send;
257 s->pre_select = dccp_pre_select;
258 s->post_select = dccp_post_select;
259 s->shutdown_clients = dccp_shutdown_clients;
260 s->help = dccp_help;
261 s->client_cmds[SENDER_ON] = NULL;
262 s->client_cmds[SENDER_OFF] = NULL;
263 s->client_cmds[SENDER_DENY] = NULL;
264 s->client_cmds[SENDER_ALLOW] = NULL;
265 s->client_cmds[SENDER_ADD] = NULL;
266 s->client_cmds[SENDER_DELETE] = NULL;
267 self = s;
268 ret = dccp_open();
269 if (ret < 0)
270 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
271 }