Merge branch 'refs/heads/t/clean_server_exit'
[paraslash.git] / dccp_send.c
1 /* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file dccp_send.c Paraslash's dccp sender. */
4
5 /*
6 * based on server.c of dccp-cs-0.01.tar.bz2,
7 * (C) 2005 Ian McDonald <imcdnzl@gmail.com>
8 */
9
10 #include <netinet/in.h>
11 #include <sys/socket.h>
12 #include <regex.h>
13 #include <sys/types.h>
14 #include <arpa/inet.h>
15 #include <sys/un.h>
16 #include <netdb.h>
17 #include <lopsub.h>
18
19 #include "server.lsg.h"
20 #include "para.h"
21 #include "error.h"
22 #include "string.h"
23 #include "afh.h"
24 #include "net.h"
25 #include "server.h"
26 #include "list.h"
27 #include "send.h"
28 #include "sched.h"
29 #include "vss.h"
30 #include "fd.h"
31
32 static struct sender_status dccp_sender_status, *dss = &dccp_sender_status;
33
34 struct dccp_fec_client {
35 struct fec_client_parms fcp;
36 struct fec_client *fc;
37 };
38
39 static void dccp_pre_select(int *max_fileno, fd_set *rfds,
40 __a_unused fd_set *wfds)
41 {
42 if (dss->listen_fd >= 0)
43 para_fd_set(dss->listen_fd, rfds, max_fileno);
44 }
45
46 /**
47 * Query the TX CCID used on the sender-client half connection.
48 * \param sockfd Server socket descriptor to query (after accept(2)).
49 * \return CCID number > 0, -1 on error/incompatibility.
50 *
51 * NB: This feature is only available on Linux > 2.6.30; on older kernels
52 * ENOPROTOOPT ("Protocol not available") will be returned.
53 */
54 static int dccp_get_tx_ccid(int sockfd)
55 {
56 int tx_ccid;
57 socklen_t len = sizeof(tx_ccid);
58
59 if (getsockopt(sockfd, SOL_DCCP,
60 DCCP_SOCKOPT_TX_CCID, &tx_ccid, &len) < 0) {
61 PARA_WARNING_LOG("DCCP_SOCKOPT_TX_CCID: %s\n", strerror(errno));
62 return -1;
63 }
64 return tx_ccid;
65 }
66
67 static void dccp_shutdown_client(struct sender_client *sc)
68 {
69 struct dccp_fec_client *dfc = sc->private_data;
70
71 vss_del_fec_client(dfc->fc);
72 shutdown_client(sc, dss);
73 }
74
75 static void dccp_shutdown_clients(void)
76 {
77 struct sender_client *sc, *tmp;
78
79 list_for_each_entry_safe(sc, tmp, &dss->client_list, node)
80 dccp_shutdown_client(sc);
81 }
82
83 static void dccp_shutdown(void)
84 {
85 dccp_shutdown_clients();
86 generic_acl_deplete(&dss->acl);
87 }
88
89 /** * Obtain current MPS according to RFC 4340, sec. 14. */
90 static int dccp_init_fec(struct sender_client *sc)
91 {
92 int mps, ret;
93 socklen_t ml = sizeof(mps);
94 uint32_t mss; /* max slize size */
95
96 /* If call fails, return some sensible minimum value */
97 ret = getsockopt(sc->fd, SOL_DCCP, DCCP_SOCKOPT_GET_CUR_MPS, &mps, &ml);
98 if (ret < 0) {
99 PARA_NOTICE_LOG("can not determine MPS: %s\n", strerror(errno));
100 mps = generic_max_transport_msg_size(sc->fd) - DCCP_MAX_HEADER;
101 }
102 PARA_INFO_LOG("current MPS = %d bytes\n", mps);
103 assert(mps > 0);
104 mss = OPT_UINT32_VAL(DCCP_MAX_SLICE_SIZE);
105 if (mss > 0 && mss <= INT_MAX)
106 mps = PARA_MIN(mps, (int)mss);
107 return mps;
108 }
109
110 static void dccp_send_fec(struct sender_client *sc, char *buf, size_t len)
111 {
112 int ret = xwrite(sc->fd, buf, len);
113
114 if (ret < 0)
115 dccp_shutdown_client(sc);
116 }
117
118 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
119 {
120 struct sender_client *sc;
121 struct dccp_fec_client *dfc;
122 int tx_ccid;
123 uint32_t k, n;
124
125 sc = accept_sender_client(dss, rfds);
126 if (!sc)
127 return;
128
129 /* If CCID identifiable, present client as <host>#<port>~<ccid> */
130 tx_ccid = dccp_get_tx_ccid(sc->fd);
131 if (tx_ccid != -1) {
132 char *tmp = make_message("%s~%d", sc->name, tx_ccid);
133
134 free(sc->name);
135 sc->name = tmp;
136 }
137 /*
138 * Bypass unused CCID paths: the sender does not receive application data
139 * from the client; by shutting down this unused communication path we can
140 * reduce processing costs a bit. See analogous comment in \ref dccp_recv.c.
141 */
142 if (shutdown(sc->fd, SHUT_RD) < 0) {
143 PARA_WARNING_LOG("%s\n", strerror(errno));
144 shutdown_client(sc, dss);
145 return;
146 }
147 dfc = para_calloc(sizeof(*dfc));
148 sc->private_data = dfc;
149 k = OPT_UINT32_VAL(DCCP_DATA_SLICES_PER_GROUP);
150 n = OPT_UINT32_VAL(DCCP_SLICES_PER_GROUP);
151 if (k == 0 || n == 0 || k >= n) {
152 PARA_WARNING_LOG("invalid FEC parameters, using defaults\n");
153 dfc->fcp.data_slices_per_group = 3;
154 dfc->fcp.slices_per_group = 4;
155 } else {
156 dfc->fcp.data_slices_per_group = k;
157 dfc->fcp.slices_per_group = n;
158 }
159 dfc->fcp.init_fec = dccp_init_fec;
160 dfc->fcp.send_fec = dccp_send_fec;
161 dfc->fcp.need_periodic_header = false;
162 dfc->fc = vss_add_fec_client(sc, &dfc->fcp);
163 }
164
165 static int dccp_com_on(__a_unused struct sender_command_data *scd)
166 {
167 generic_com_on(dss, IPPROTO_DCCP);
168 return 1;
169 }
170
171 static int dccp_com_off(__a_unused struct sender_command_data *scd)
172 {
173 dccp_shutdown_clients();
174 generic_com_off(dss);
175 return 1;
176 }
177
178
179 static int dccp_com_deny(struct sender_command_data *scd)
180 {
181 generic_com_deny(scd, dss);
182 return 1;
183 }
184
185 static int dccp_com_allow(struct sender_command_data *scd)
186 {
187 generic_com_allow(scd, dss);
188 return 1;
189 }
190
191 /**
192 * Return list of available CCIDs or warning, in static buffer.
193 */
194 static const char *dccp_list_available_ccids(void)
195 {
196 /* Worst case length: n * 3 digits + n-1 spaces + '\0' */
197 static char list[DCCP_MAX_HOST_CCIDS * 4];
198 uint8_t *ccids;
199 int i, len, nccids;
200
201 nccids = dccp_available_ccids(&ccids);
202 if (nccids < 0) {
203 snprintf(list, sizeof(list), "Unable to query available CCIDs");
204 } else {
205 for (i = len = 0; i < nccids; i++)
206 len += snprintf(list + len, sizeof(list) - len,
207 "%s%d", i ? " " : "", ccids[i]);
208 }
209 return list;
210 }
211
212 static char *dccp_status(void)
213 {
214 char *status = generic_sender_status(dss, "dccp");
215 char *result = make_message("%ssupported ccids: %s\n", status,
216 dccp_list_available_ccids());
217 free(status);
218 return result;
219 }
220
221 /*
222 * Initialize the client list and the access control list and listen on the
223 * dccp port.
224 */
225 static void dccp_send_init(void)
226 {
227 init_sender_status(dss, OPT_RESULT(DCCP_ACCESS),
228 OPT_UINT32_VAL(DCCP_PORT), OPT_UINT32_VAL(DCCP_MAX_CLIENTS),
229 OPT_GIVEN(DCCP_DEFAULT_DENY));
230 generic_com_on(dss, IPPROTO_DCCP);
231 }
232
233 /**
234 * The DCCP sender.
235 *
236 * This sender offers congestion control not available in plain TCP. Most
237 * methods of the sender structure are implemented as simple wrappers for the
238 * generic functions defined in \ref send_common.c. Like UDP streams, DCCP
239 * streams are sent FEC-encoded.
240 */
241 const struct sender dccp_sender = {
242 .name = "dccp",
243 .init = dccp_send_init,
244 .shutdown = dccp_shutdown,
245 .pre_select = dccp_pre_select,
246 .post_select = dccp_post_select,
247 .shutdown_clients = dccp_shutdown_clients,
248 .client_cmds = {
249 [SENDER_on] = dccp_com_on,
250 [SENDER_off] = dccp_com_off,
251 [SENDER_deny] = dccp_com_deny,
252 [SENDER_allow] = dccp_com_allow,
253 },
254 .help = generic_sender_help,
255 .status = dccp_status,
256 };