dccp_send.c

   1 /*
   2  * Copyright (C) 2006-2013 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 <netinet/in.h>
  15 #include <sys/socket.h>
  16 #include <regex.h>
  17 #include <sys/types.h>
  18 #include <osl.h>
  19 #include <arpa/inet.h>
  20 #include <sys/un.h>
  21 #include <netdb.h>
  22
  23 #include "para.h"
  24 #include "error.h"
  25 #include "string.h"
  26 #include "afh.h"
  27 #include "afs.h"
  28 #include "server.h"
  29 #include "net.h"
  30 #include "list.h"
  31 #include "send.h"
  32 #include "sched.h"
  33 #include "vss.h"
  34 #include "fd.h"
  35 #include "close_on_fork.h"
  36 #include "chunk_queue.h"
  37 #include "server.cmdline.h"
  38 #include "acl.h"
  39
  40 static struct sender_status dccp_sender_status, *dss = &dccp_sender_status;
  41
  42 struct dccp_fec_client {
  43         struct fec_client_parms fcp;
  44         struct fec_client *fc;
  45 };
  46
  47 static void dccp_pre_select(int *max_fileno, fd_set *rfds,
  48                 __a_unused fd_set *wfds)
  49 {
  50         if (dss->listen_fd >= 0)
  51                 para_fd_set(dss->listen_fd, rfds, max_fileno);
  52 }
  53
  54 /**
  55  * Query the TX CCID used on the sender-client half connection.
  56  * \param sockfd Server socket descriptor to query (after accept(2)).
  57  * \return CCID number > 0, -1 on error/incompatibility.
  58  *
  59  * NB: This feature is only available on Linux > 2.6.30; on older kernels
  60  * ENOPROTOOPT ("Protocol not available") will be returned.
  61  */
  62 static int dccp_get_tx_ccid(int sockfd)
  63 {
  64         int tx_ccid;
  65         socklen_t len = sizeof(tx_ccid);
  66
  67         if (getsockopt(sockfd, SOL_DCCP,
  68                        DCCP_SOCKOPT_TX_CCID, &tx_ccid, &len) < 0) {
  69                 PARA_WARNING_LOG("DCCP_SOCKOPT_TX_CCID: %s\n", strerror(errno));
  70                 return -1;
  71         }
  72         return tx_ccid;
  73 }
  74
  75 static void dccp_shutdown_client(struct sender_client *sc)
  76 {
  77         struct dccp_fec_client *dfc = sc->private_data;
  78
  79         vss_del_fec_client(dfc->fc);
  80         shutdown_client(sc, dss);
  81 }
  82
  83 static void dccp_shutdown_clients(void)
  84 {
  85         struct sender_client *sc, *tmp;
  86
  87         list_for_each_entry_safe(sc, tmp, &dss->client_list, node)
  88                 dccp_shutdown_client(sc);
  89 }
  90
  91 /** * Obtain current MPS according to RFC 4340, sec. 14. */
  92 static int dccp_init_fec(struct sender_client *sc)
  93 {
  94         int mps, ret;
  95         socklen_t ml = sizeof(mps);
  96
  97         /* If call fails, return some sensible minimum value */
  98         ret = getsockopt(sc->fd, SOL_DCCP, DCCP_SOCKOPT_GET_CUR_MPS, &mps, &ml);
  99         if (ret < 0) {
 100                 PARA_NOTICE_LOG("can not determine MPS: %s\n", strerror(errno));
 101                 mps = generic_max_transport_msg_size(sc->fd) - DCCP_MAX_HEADER;
 102         }
 103         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 104         assert(mps > 0);
 105         if (conf.dccp_max_slice_size_arg > 0)
 106                 mps = PARA_MIN(mps, conf.dccp_max_slice_size_arg);
 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
 124         sc = accept_sender_client(dss, rfds);
 125         if (!sc)
 126                 return;
 127
 128         /* If CCID identifiable, present client as <host>#<port>~<ccid> */
 129         tx_ccid = dccp_get_tx_ccid(sc->fd);
 130         if (tx_ccid != -1) {
 131                 char *tmp = make_message("%s~%d", sc->name, tx_ccid);
 132
 133                 free(sc->name);
 134                 sc->name = tmp;
 135         }
 136         /*
 137          * Bypass unused CCID paths: the sender does not receive application data
 138          * from the client; by shutting down this unused communication path we can
 139          * reduce processing costs a bit. See analogous comment in dccp_recv.c.
 140          */
 141         if (shutdown(sc->fd, SHUT_RD) < 0) {
 142                 PARA_WARNING_LOG("%s\n", strerror(errno));
 143                 shutdown_client(sc, dss);
 144                 return;
 145         }
 146         dfc = para_calloc(sizeof(*dfc));
 147         sc->private_data = dfc;
 148         dfc->fcp.data_slices_per_group  = conf.dccp_data_slices_per_group_arg;
 149         dfc->fcp.slices_per_group       = conf.dccp_slices_per_group_arg;
 150         dfc->fcp.init_fec               = dccp_init_fec;
 151         dfc->fcp.send_fec               = dccp_send_fec;
 152         dfc->fcp.need_periodic_header   = false;
 153         dfc->fc = vss_add_fec_client(sc, &dfc->fcp);
 154 }
 155
 156 static int dccp_com_on(__a_unused struct sender_command_data *scd)
 157 {
 158         return generic_com_on(dss, IPPROTO_DCCP);
 159 }
 160
 161 static int dccp_com_off(__a_unused struct sender_command_data *scd)
 162 {
 163         dccp_shutdown_clients();
 164         generic_com_off(dss);
 165         return 1;
 166 }
 167
 168
 169 static int dccp_com_deny(struct sender_command_data *scd)
 170 {
 171         generic_com_deny(scd, dss);
 172         return 1;
 173 }
 174
 175 static int dccp_com_allow(struct sender_command_data *scd)
 176 {
 177         generic_com_allow(scd, dss);
 178         return 1;
 179 }
 180
 181 /**
 182  * Return list of available CCIDs or warning, in static buffer.
 183  */
 184 static const char *dccp_list_available_ccids(void)
 185 {
 186         /* Worst case length: n * 3 digits + n-1 spaces + '\0' */
 187         static char list[DCCP_MAX_HOST_CCIDS * 4];
 188         uint8_t *ccids;
 189         int i, len, nccids;
 190
 191         nccids = dccp_available_ccids(&ccids);
 192         if (nccids < 0) {
 193                 snprintf(list, sizeof(list), "Unable to query available CCIDs");
 194         } else {
 195                 for (i = len = 0; i < nccids; i++)
 196                         len += snprintf(list + len, sizeof(list) - len,
 197                                         "%s%d", i ? " " : "", ccids[i]);
 198         }
 199         return list;
 200 }
 201
 202 static char *dccp_info(void)
 203 {
 204         char *info = get_sender_info(dss, "dccp");
 205         char *ret  = make_message("%s" "\tsupported ccids: %s\n",
 206                                   info, dccp_list_available_ccids());
 207         free(info);
 208         return ret;
 209 }
 210
 211 /**
 212  * The init function of the dccp sender.
 213  *
 214  * \param s pointer to the dccp sender struct.
 215  *
 216  * It initializes all function pointers of \a s and starts
 217  * listening on the given port.
 218  */
 219 void dccp_send_init(struct sender *s)
 220 {
 221         int ret, k, n;
 222
 223         s->info = dccp_info;
 224         s->send = NULL;
 225         s->pre_select = dccp_pre_select;
 226         s->post_select = dccp_post_select;
 227         s->shutdown_clients = dccp_shutdown_clients;
 228         s->resolve_target = NULL;
 229         s->help = generic_sender_help;
 230         s->client_cmds[SENDER_ON] = dccp_com_on;
 231         s->client_cmds[SENDER_OFF] = dccp_com_off;
 232         s->client_cmds[SENDER_DENY] = dccp_com_deny;
 233         s->client_cmds[SENDER_ALLOW] = dccp_com_allow;
 234         s->client_cmds[SENDER_ADD] = NULL;
 235         s->client_cmds[SENDER_DELETE] = NULL;
 236
 237         k = conf.dccp_data_slices_per_group_arg;
 238         n = conf.dccp_slices_per_group_arg;
 239
 240         if (k <= 0 || n <= 0 || k >= n) {
 241                 PARA_WARNING_LOG("invalid FEC parameters, using defaults\n");
 242                 conf.dccp_data_slices_per_group_arg = 3;
 243                 conf.dccp_slices_per_group_arg = 4;
 244         }
 245
 246         init_sender_status(dss, conf.dccp_access_arg, conf.dccp_access_given,
 247                 conf.dccp_port_arg, conf.dccp_max_clients_arg,
 248                 conf.dccp_default_deny_given);
 249         ret = generic_com_on(dss, IPPROTO_DCCP);
 250         if (ret < 0)
 251                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 252 }