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 #include "close_on_fork.h"
  32 #include "chunk_queue.h"
  33 #include "acl.h"
  34
  35 static struct sender_status dccp_sender_status, *dss = &dccp_sender_status;
  36
  37 struct dccp_fec_client {
  38         struct fec_client_parms fcp;
  39         struct fec_client *fc;
  40 };
  41
  42 static void dccp_pre_select(int *max_fileno, fd_set *rfds,
  43                 __a_unused fd_set *wfds)
  44 {
  45         if (dss->listen_fd >= 0)
  46                 para_fd_set(dss->listen_fd, 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 /** * Obtain current MPS according to RFC 4340, sec. 14. */
  87 static int dccp_init_fec(struct sender_client *sc)
  88 {
  89         int mps, ret;
  90         socklen_t ml = sizeof(mps);
  91         uint32_t mss; /* max slize size */
  92
  93         /* If call fails, return some sensible minimum value */
  94         ret = getsockopt(sc->fd, SOL_DCCP, DCCP_SOCKOPT_GET_CUR_MPS, &mps, &ml);
  95         if (ret < 0) {
  96                 PARA_NOTICE_LOG("can not determine MPS: %s\n", strerror(errno));
  97                 mps = generic_max_transport_msg_size(sc->fd) - DCCP_MAX_HEADER;
  98         }
  99         PARA_INFO_LOG("current MPS = %d bytes\n", mps);
 100         assert(mps > 0);
 101         mss = OPT_UINT32_VAL(DCCP_MAX_SLICE_SIZE);
 102         if (mss > 0 && mss <= INT_MAX)
 103                 mps = PARA_MIN(mps, (int)mss);
 104         return mps;
 105 }
 106
 107 static void dccp_send_fec(struct sender_client *sc, char *buf, size_t len)
 108 {
 109         int ret = xwrite(sc->fd, buf, len);
 110
 111         if (ret < 0)
 112                 dccp_shutdown_client(sc);
 113 }
 114
 115 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
 116 {
 117         struct sender_client *sc;
 118         struct dccp_fec_client *dfc;
 119         int tx_ccid;
 120         uint32_t k, n;
 121
 122         sc = accept_sender_client(dss, rfds);
 123         if (!sc)
 124                 return;
 125
 126         /* If CCID identifiable, present client as <host>#<port>~<ccid> */
 127         tx_ccid = dccp_get_tx_ccid(sc->fd);
 128         if (tx_ccid != -1) {
 129                 char *tmp = make_message("%s~%d", sc->name, tx_ccid);
 130
 131                 free(sc->name);
 132                 sc->name = tmp;
 133         }
 134         /*
 135          * Bypass unused CCID paths: the sender does not receive application data
 136          * from the client; by shutting down this unused communication path we can
 137          * reduce processing costs a bit. See analogous comment in \ref dccp_recv.c.
 138          */
 139         if (shutdown(sc->fd, SHUT_RD) < 0) {
 140                 PARA_WARNING_LOG("%s\n", strerror(errno));
 141                 shutdown_client(sc, dss);
 142                 return;
 143         }
 144         dfc = para_calloc(sizeof(*dfc));
 145         sc->private_data = dfc;
 146         k = OPT_UINT32_VAL(DCCP_DATA_SLICES_PER_GROUP);
 147         n = OPT_UINT32_VAL(DCCP_SLICES_PER_GROUP);
 148         if (k == 0 || n == 0 || k >= n) {
 149                 PARA_WARNING_LOG("invalid FEC parameters, using defaults\n");
 150                 dfc->fcp.data_slices_per_group = 3;
 151                 dfc->fcp.slices_per_group = 4;
 152         } else {
 153                 dfc->fcp.data_slices_per_group = k;
 154                 dfc->fcp.slices_per_group = n;
 155         }
 156         dfc->fcp.init_fec               = dccp_init_fec;
 157         dfc->fcp.send_fec               = dccp_send_fec;
 158         dfc->fcp.need_periodic_header   = false;
 159         dfc->fc = vss_add_fec_client(sc, &dfc->fcp);
 160 }
 161
 162 static int dccp_com_on(__a_unused struct sender_command_data *scd)
 163 {
 164         generic_com_on(dss, IPPROTO_DCCP);
 165         return 1;
 166 }
 167
 168 static int dccp_com_off(__a_unused struct sender_command_data *scd)
 169 {
 170         dccp_shutdown_clients();
 171         generic_com_off(dss);
 172         return 1;
 173 }
 174
 175
 176 static int dccp_com_deny(struct sender_command_data *scd)
 177 {
 178         generic_com_deny(scd, dss);
 179         return 1;
 180 }
 181
 182 static int dccp_com_allow(struct sender_command_data *scd)
 183 {
 184         generic_com_allow(scd, dss);
 185         return 1;
 186 }
 187
 188 /**
 189  * Return list of available CCIDs or warning, in static buffer.
 190  */
 191 static const char *dccp_list_available_ccids(void)
 192 {
 193         /* Worst case length: n * 3 digits + n-1 spaces + '\0' */
 194         static char list[DCCP_MAX_HOST_CCIDS * 4];
 195         uint8_t *ccids;
 196         int i, len, nccids;
 197
 198         nccids = dccp_available_ccids(&ccids);
 199         if (nccids < 0) {
 200                 snprintf(list, sizeof(list), "Unable to query available CCIDs");
 201         } else {
 202                 for (i = len = 0; i < nccids; i++)
 203                         len += snprintf(list + len, sizeof(list) - len,
 204                                         "%s%d", i ? " " : "", ccids[i]);
 205         }
 206         return list;
 207 }
 208
 209 static char *dccp_status(void)
 210 {
 211         char *status = generic_sender_status(dss, "dccp");
 212         char *result = make_message("%ssupported ccids: %s\n", status,
 213                 dccp_list_available_ccids());
 214         free(status);
 215         return result;
 216 }
 217
 218 /**
 219  * The init function of the dccp sender.
 220  *
 221  * \param s pointer to the dccp sender struct.
 222  *
 223  * It initializes all function pointers of \a s and starts
 224  * listening on the given port.
 225  */
 226 void dccp_send_init(struct sender *s)
 227 {
 228         s->status = dccp_status;
 229         s->send = NULL;
 230         s->pre_select = dccp_pre_select;
 231         s->post_select = dccp_post_select;
 232         s->shutdown_clients = dccp_shutdown_clients;
 233         s->resolve_target = NULL;
 234         s->help = generic_sender_help;
 235         s->client_cmds[SENDER_on] = dccp_com_on;
 236         s->client_cmds[SENDER_off] = dccp_com_off;
 237         s->client_cmds[SENDER_deny] = dccp_com_deny;
 238         s->client_cmds[SENDER_allow] = dccp_com_allow;
 239         s->client_cmds[SENDER_add] = NULL;
 240         s->client_cmds[SENDER_delete] = NULL;
 241
 242         init_sender_status(dss, OPT_RESULT(DCCP_ACCESS),
 243                 OPT_UINT32_VAL(DCCP_PORT), OPT_UINT32_VAL(DCCP_MAX_CLIENTS),
 244                 OPT_GIVEN(DCCP_DEFAULT_DENY));
 245         generic_com_on(dss, IPPROTO_DCCP);
 246 }