01_DCCP_shutdown-unnecessary.diff
[paraslash.git] / dccp_send.c
1 /*
2 * Copyright (C) 2006-2007 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 (!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 add_close_on_fork_list(listen_fd);
102 mark_fd_nonblocking(listen_fd);
103 return 1;
104 }
105
106 static void dccp_shutdown_client(struct dccp_client *dc)
107 {
108 PARA_DEBUG_LOG("shutting down %s (fd %d)\n", dc->name, dc->fd);
109 free(dc->name);
110 close(dc->fd);
111 del_close_on_fork_list(dc->fd);
112 cq_destroy(dc->cq);
113 list_del(&dc->node);
114 free(dc);
115 }
116
117 /*
118 * ret: Negative on errors, zero if nothing was written and write returned
119 * EAGAIN, number of bytes written else.
120 */
121 static int dccp_write(int fd, const char *buf, size_t len)
122 {
123 size_t written = 0;
124 int ret = 0;
125
126 while (written < len) {
127 ret = write(fd, buf + written, PARA_MIN(1024, len - written));
128 /*
129 * Error handling: CCID3 has a sending wait queue which fills up and is
130 * emptied asynchronously. The EAGAIN case means that there is currently
131 * no space in the wait queue, but this can change at any moment and is
132 * thus not an error condition.
133 */
134 if (ret < 0 && errno == EAGAIN)
135 return written;
136 if (ret < 0) {
137 PARA_ERROR_LOG("%s\n", strerror(errno));
138 return -E_DCCP_WRITE;
139 }
140 written += ret;
141 }
142 return written;
143 }
144
145 static int queue_chunk_or_shutdown(struct dccp_client *dc, long unsigned chunk_num,
146 size_t sent)
147 {
148 int ret = cq_enqueue(dc->cq, chunk_num, sent);
149 if (ret < 0) {
150 PARA_NOTICE_LOG("enqueue error\n");
151 dccp_shutdown_client(dc);
152 }
153 return ret;
154 }
155
156 static int send_queued_chunks(struct dccp_client *dc)
157 {
158 struct queued_chunk *qc;
159 while ((qc = cq_peek(dc->cq))) {
160 char *buf;
161 size_t len;
162 int ret;
163 cq_get(qc, &buf, &len);
164 ret = dccp_write(dc->fd, buf, len);
165 if (ret < 0)
166 return ret;
167 cq_update(dc->cq, ret);
168 if (ret != len)
169 return 1;
170 cq_dequeue(dc->cq);
171 }
172 return 1;
173 }
174
175 static void dccp_send(long unsigned current_chunk,
176 __a_unused long unsigned chunks_sent, const char *buf, size_t len)
177 {
178 struct dccp_client *dc, *tmp;
179 int ret;
180 char *header_buf;
181 size_t header_len;
182
183 if (listen_fd < 0 || !len)
184 return;
185
186 list_for_each_entry_safe(dc, tmp, &clients, node) {
187 if (!dc->header_sent && current_chunk) {
188 header_buf = vss_get_header(&header_len);
189 if (header_buf && header_len > 0) {
190 if (queue_chunk_or_shutdown(dc, -1U, 0) < 0)
191 continue;
192 }
193 dc->header_sent = 1;
194 }
195 ret = send_queued_chunks(dc);
196 if (ret < 0) {
197 dccp_shutdown_client(dc);
198 continue;
199 }
200 // PARA_DEBUG_LOG("writing %d bytes to fd %d\n", len, dc->fd);
201 ret = dccp_write(dc->fd, buf, len);
202 if (ret < 0) {
203 PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
204 dccp_shutdown_client(dc);
205 continue;
206 }
207 if (ret != len)
208 queue_chunk_or_shutdown(dc, current_chunk, ret);
209 }
210 }
211
212 static void dccp_shutdown_clients(void)
213 {
214 struct dccp_client *dc, *tmp;
215
216 list_for_each_entry_safe(dc, tmp, &clients, node)
217 dccp_shutdown_client(dc);
218 }
219
220 static char *dccp_info(void)
221 {
222 static char *buf;
223 int num_clients = 0;
224 struct dccp_client *dc, *tmp;
225
226 free(buf);
227 list_for_each_entry_safe(dc, tmp, &clients, node)
228 num_clients++;
229 buf = make_message("dccp connected clients: %d\n", num_clients);
230 return buf;
231 }
232
233 static char *dccp_help(void)
234 {
235 return make_message("no help available\n");
236 }
237
238 /**
239 * the init function of the dccp sender
240 *
241 * \param s pointer to the dccp sender struct
242 *
243 * It initializes all function pointers of \a s and starts
244 * listening on the given port.
245 */
246 void dccp_send_init(struct sender *s)
247 {
248 int ret;
249
250 INIT_LIST_HEAD(&clients);
251 s->info = dccp_info;
252 s->send = dccp_send;
253 s->pre_select = dccp_pre_select;
254 s->post_select = dccp_post_select;
255 s->shutdown_clients = dccp_shutdown_clients;
256 s->help = dccp_help;
257 s->client_cmds[SENDER_ON] = NULL;
258 s->client_cmds[SENDER_OFF] = NULL;
259 s->client_cmds[SENDER_DENY] = NULL;
260 s->client_cmds[SENDER_ALLOW] = NULL;
261 s->client_cmds[SENDER_ADD] = NULL;
262 s->client_cmds[SENDER_DELETE] = NULL;
263 self = s;
264 ret = dccp_open();
265 if (ret < 0) {
266 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
267 s->status = SENDER_OFF;
268 } else
269 s->status = SENDER_ON;
270 }