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         unsigned n;
  43
  44         FOR_EACH_LISTEN_FD(n, dss)
  45                 if (dss->listen_fds[n] >= 0)
  46                         para_fd_set(dss->listen_fds[n], rfds, max_fileno);
  47 }
  48
  49 /**
  50  * Query the TX CCID used on the sender-client half connection.
  51  * \param sockfd Server socket descriptor to query (after accept(2)).
  52  * \return CCID number > 0, -1 on error/incompatibility.
  53  *
  54  * NB: This feature is only available on Linux > 2.6.30; on older kernels
  55  * ENOPROTOOPT ("Protocol not available") will be returned.
  56  */
  57 static int dccp_get_tx_ccid(int sockfd)
  58 {
  59         int tx_ccid;
  60         socklen_t len = sizeof(tx_ccid);
  61
  62         if (getsockopt(sockfd, SOL_DCCP,
  63                        DCCP_SOCKOPT_TX_CCID, &tx_ccid, &len) < 0) {
  64                 PARA_WARNING_LOG("DCCP_SOCKOPT_TX_CCID: %s\n", strerror(errno));
  65                 return -1;
  66         }
  67         return tx_ccid;
  68 }
  69
  70 static void dccp_shutdown_client(struct sender_client *sc)
  71 {
  72         struct dccp_fec_client *dfc = sc->private_data;
  73
  74         vss_del_fec_client(dfc->fc);
  75         shutdown_client(sc, dss);
  76 }
  77
  78 static void dccp_shutdown_clients(void)
  79 {
  80         struct sender_client *sc, *tmp;
  81
  82         list_for_each_entry_safe(sc, tmp, &dss->client_list, node)
  83                 dccp_shutdown_client(sc);
  84 }
  85
  86 static void dccp_shutdown(void)
  87 {
  88         dccp_shutdown_clients();
  89         generic_acl_deplete(&dss->acl);
  90 }
  91
  92 /** * Obtain current MPS according to RFC 4340, sec. 14. */
  93 static int dccp_init_fec(struct sender_client *sc)
  94 {
  95         int mps, ret;
  96         socklen_t ml = sizeof(mps);
  97         uint32_t mss; /* max slize size */
  98
  99         /* If call fails, return some sensible minimum value */
 100         ret = getsockopt(sc->fd, SOL_DCCP, DCCP_SOCKOPT_GET_CUR_MPS, &mps, &ml);
 101         if (ret < 0) {
 102                 PARA_NOTICE_LOG("can not determine MPS: %s\n", strerror(errno));
 103                 mps = generic_max_transport_msg_size(sc->fd) - DCCP_MAX_HEADER;
 104         }
 105         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 106         assert(mps > 0);
 107         mss = OPT_UINT32_VAL(DCCP_MAX_SLICE_SIZE);
 108         if (mss > 0 && mss <= INT_MAX)
 109                 mps = PARA_MIN(mps, (int)mss);
 110         return mps;
 111 }
 112
 113 static void dccp_send_fec(struct sender_client *sc, char *buf, size_t len)
 114 {
 115         int ret = xwrite(sc->fd, buf, len);
 116
 117         if (ret < 0)
 118                 dccp_shutdown_client(sc);
 119 }
 120
 121 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
 122 {
 123         struct sender_client *sc;
 124         struct dccp_fec_client *dfc;
 125         int tx_ccid;
 126         uint32_t k, n;
 127
 128         sc = accept_sender_client(dss, rfds);
 129         if (!sc)
 130                 return;
 131
 132         /* If CCID identifiable, present client as <host>#<port>~<ccid> */
 133         tx_ccid = dccp_get_tx_ccid(sc->fd);
 134         if (tx_ccid != -1) {
 135                 char *tmp = make_message("%s~%d", sc->name, tx_ccid);
 136
 137                 free(sc->name);
 138                 sc->name = tmp;
 139         }
 140         /*
 141          * Bypass unused CCID paths: the sender does not receive application data
 142          * from the client; by shutting down this unused communication path we can
 143          * reduce processing costs a bit. See analogous comment in \ref dccp_recv.c.
 144          */
 145         if (shutdown(sc->fd, SHUT_RD) < 0) {
 146                 PARA_WARNING_LOG("%s\n", strerror(errno));
 147                 shutdown_client(sc, dss);
 148                 return;
 149         }
 150         dfc = para_calloc(sizeof(*dfc));
 151         sc->private_data = dfc;
 152         k = OPT_UINT32_VAL(DCCP_DATA_SLICES_PER_GROUP);
 153         n = OPT_UINT32_VAL(DCCP_SLICES_PER_GROUP);
 154         if (k == 0 || n == 0 || k >= n) {
 155                 PARA_WARNING_LOG("invalid FEC parameters, using defaults\n");
 156                 dfc->fcp.data_slices_per_group = 3;
 157                 dfc->fcp.slices_per_group = 4;
 158         } else {
 159                 dfc->fcp.data_slices_per_group = k;
 160                 dfc->fcp.slices_per_group = n;
 161         }
 162         dfc->fcp.init_fec               = dccp_init_fec;
 163         dfc->fcp.send_fec               = dccp_send_fec;
 164         dfc->fcp.need_periodic_header   = false;
 165         dfc->fc = vss_add_fec_client(sc, &dfc->fcp);
 166 }
 167
 168 static int dccp_com_on(__a_unused struct sender_command_data *scd)
 169 {
 170         generic_com_on(dss, IPPROTO_DCCP);
 171         return 1;
 172 }
 173
 174 static int dccp_com_off(__a_unused struct sender_command_data *scd)
 175 {
 176         dccp_shutdown_clients();
 177         generic_com_off(dss);
 178         return 1;
 179 }
 180
 181
 182 static int dccp_com_deny(struct sender_command_data *scd)
 183 {
 184         generic_com_deny(scd, dss);
 185         return 1;
 186 }
 187
 188 static int dccp_com_allow(struct sender_command_data *scd)
 189 {
 190         generic_com_allow(scd, dss);
 191         return 1;
 192 }
 193
 194 /**
 195  * Return list of available CCIDs or warning, in static buffer.
 196  */
 197 static const char *dccp_list_available_ccids(void)
 198 {
 199         /* Worst case length: n * 3 digits + n-1 spaces + '\0' */
 200         static char list[DCCP_MAX_HOST_CCIDS * 4];
 201         uint8_t *ccids;
 202         int i, len, nccids;
 203
 204         nccids = dccp_available_ccids(&ccids);
 205         if (nccids < 0) {
 206                 snprintf(list, sizeof(list), "Unable to query available CCIDs");
 207         } else {
 208                 for (i = len = 0; i < nccids; i++)
 209                         len += snprintf(list + len, sizeof(list) - len,
 210                                         "%s%d", i ? " " : "", ccids[i]);
 211         }
 212         return list;
 213 }
 214
 215 static char *dccp_status(void)
 216 {
 217         char *status = generic_sender_status(dss, "dccp");
 218         char *result = make_message("%ssupported ccids: %s\n", status,
 219                 dccp_list_available_ccids());
 220         free(status);
 221         return result;
 222 }
 223
 224 /*
 225  * Initialize the client list and the access control list and listen on the
 226  * dccp port.
 227  */
 228 static void dccp_send_init(void)
 229 {
 230         init_sender_status(dss, OPT_RESULT(DCCP_ACCESS),
 231                 OPT_RESULT(DCCP_LISTEN_ADDRESS),
 232                 OPT_UINT32_VAL(DCCP_PORT), OPT_UINT32_VAL(DCCP_MAX_CLIENTS),
 233                 OPT_GIVEN(DCCP_DEFAULT_DENY));
 234         generic_com_on(dss, IPPROTO_DCCP);
 235 }
 236
 237 /**
 238  * The DCCP sender.
 239  *
 240  * This sender offers congestion control not available in plain TCP. Most
 241  * methods of the sender structure are implemented as simple wrappers for the
 242  * generic functions defined in \ref send_common.c. Like UDP streams, DCCP
 243  * streams are sent FEC-encoded.
 244  */
 245 const struct sender dccp_sender = {
 246         .name = "dccp",
 247         .init = dccp_send_init,
 248         .shutdown = dccp_shutdown,
 249         .pre_select = dccp_pre_select,
 250         .post_select = dccp_post_select,
 251         .shutdown_clients = dccp_shutdown_clients,
 252         .client_cmds = {
 253                 [SENDER_on] = dccp_com_on,
 254                 [SENDER_off] = dccp_com_off,
 255                 [SENDER_deny] = dccp_com_deny,
 256                 [SENDER_allow] = dccp_com_allow,
 257         },
 258         .help = generic_sender_help,
 259         .status = dccp_status,
 260 };