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 };