err.no Git - linux-2.6/blob - net/dccp/minisocks.c

   1 /*
   2  *  net/dccp/minisocks.c
   3  *
   4  *  An implementation of the DCCP protocol
   5  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/dccp.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/timer.h>
  17
  18 #include <net/sock.h>
  19 #include <net/xfrm.h>
  20 #include <net/inet_timewait_sock.h>
  21
  22 #include "ackvec.h"
  23 #include "ccid.h"
  24 #include "dccp.h"
  25
  26 struct inet_timewait_death_row dccp_death_row = {
  27         .sysctl_max_tw_buckets = NR_FILE * 2,
  28         .period         = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
  29         .death_lock     = SPIN_LOCK_UNLOCKED,
  30         .hashinfo       = &dccp_hashinfo,
  31         .tw_timer       = TIMER_INITIALIZER(inet_twdr_hangman, 0,
  32                                             (unsigned long)&dccp_death_row),
  33         .twkill_work    = __WORK_INITIALIZER(dccp_death_row.twkill_work,
  34                                              inet_twdr_twkill_work,
  35                                              &dccp_death_row),
  36 /* Short-time timewait calendar */
  37
  38         .twcal_hand     = -1,
  39         .twcal_timer    = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
  40                                             (unsigned long)&dccp_death_row),
  41 };
  42
  43 EXPORT_SYMBOL_GPL(dccp_death_row);
  44
  45 void dccp_time_wait(struct sock *sk, int state, int timeo)
  46 {
  47         struct inet_timewait_sock *tw = NULL;
  48
  49         if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
  50                 tw = inet_twsk_alloc(sk, state);
  51
  52         if (tw != NULL) {
  53                 const struct inet_connection_sock *icsk = inet_csk(sk);
  54                 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
  55
  56                 /* Linkage updates. */
  57                 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
  58
  59                 /* Get the TIME_WAIT timeout firing. */
  60                 if (timeo < rto)
  61                         timeo = rto;
  62
  63                 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
  64                 if (state == DCCP_TIME_WAIT)
  65                         timeo = DCCP_TIMEWAIT_LEN;
  66
  67                 inet_twsk_schedule(tw, &dccp_death_row, timeo,
  68                                    DCCP_TIMEWAIT_LEN);
  69                 inet_twsk_put(tw);
  70         } else {
  71                 /* Sorry, if we're out of memory, just CLOSE this
  72                  * socket up.  We've got bigger problems than
  73                  * non-graceful socket closings.
  74                  */
  75                 LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket "
  76                                          "table overflow\n");
  77         }
  78
  79         dccp_done(sk);
  80 }
  81
  82 struct sock *dccp_create_openreq_child(struct sock *sk,
  83                                        const struct request_sock *req,
  84                                        const struct sk_buff *skb)
  85 {
  86         /*
  87          * Step 3: Process LISTEN state
  88          *
  89          * // Generate a new socket and switch to that socket
  90          * Set S := new socket for this port pair
  91          */
  92         struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
  93
  94         if (newsk != NULL) {
  95                 const struct dccp_request_sock *dreq = dccp_rsk(req);
  96                 struct inet_connection_sock *newicsk = inet_csk(sk);
  97                 struct dccp_sock *newdp = dccp_sk(newsk);
  98
  99                 newdp->dccps_role          = DCCP_ROLE_SERVER;
 100                 newdp->dccps_hc_rx_ackvec  = NULL;
 101                 newdp->dccps_service_list  = NULL;
 102                 newdp->dccps_service       = dreq->dreq_service;
 103                 newicsk->icsk_rto          = DCCP_TIMEOUT_INIT;
 104                 do_gettimeofday(&newdp->dccps_epoch);
 105
 106                 if (newdp->dccps_options.dccpo_send_ack_vector) {
 107                         newdp->dccps_hc_rx_ackvec =
 108                                 dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN,
 109                                                   GFP_ATOMIC);
 110                         /*
 111                          * XXX: We're using the same CCIDs set on the parent,
 112                          * i.e. sk_clone copied the master sock and left the
 113                          * CCID pointers for this child, that is why we do the
 114                          * __ccid_get calls.
 115                          */
 116                         if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
 117                                 goto out_free;
 118                 }
 119
 120                 if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid,
 121                                              newsk) != 0 ||
 122                              ccid_hc_tx_init(newdp->dccps_hc_tx_ccid,
 123                                              newsk) != 0)) {
 124                         dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
 125                         ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk);
 126                         ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk);
 127 out_free:
 128                         /* It is still raw copy of parent, so invalidate
 129                          * destructor and make plain sk_free() */
 130                         newsk->sk_destruct = NULL;
 131                         sk_free(newsk);
 132                         return NULL;
 133                 }
 134
 135                 __ccid_get(newdp->dccps_hc_rx_ccid);
 136                 __ccid_get(newdp->dccps_hc_tx_ccid);
 137
 138                 /*
 139                  * Step 3: Process LISTEN state
 140                  *
 141                  *      Choose S.ISS (initial seqno) or set from Init Cookie
 142                  *      Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
 143                  *      Cookie
 144                  */
 145
 146                 /* See dccp_v4_conn_request */
 147                 newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd;
 148
 149                 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
 150                 dccp_update_gsr(newsk, dreq->dreq_isr);
 151
 152                 newdp->dccps_iss = dreq->dreq_iss;
 153                 dccp_update_gss(newsk, dreq->dreq_iss);
 154
 155                 /*
 156                  * SWL and AWL are initially adjusted so that they are not less than
 157                  * the initial Sequence Numbers received and sent, respectively:
 158                  *      SWL := max(GSR + 1 - floor(W/4), ISR),
 159                  *      AWL := max(GSS - W' + 1, ISS).
 160                  * These adjustments MUST be applied only at the beginning of the
 161                  * connection.
 162                  */
 163                 dccp_set_seqno(&newdp->dccps_swl,
 164                                max48(newdp->dccps_swl, newdp->dccps_isr));
 165                 dccp_set_seqno(&newdp->dccps_awl,
 166                                max48(newdp->dccps_awl, newdp->dccps_iss));
 167
 168                 dccp_init_xmit_timers(newsk);
 169
 170                 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
 171         }
 172         return newsk;
 173 }
 174
 175 EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
 176
 177 /*
 178  * Process an incoming packet for RESPOND sockets represented
 179  * as an request_sock.
 180  */
 181 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 182                             struct request_sock *req,
 183                             struct request_sock **prev)
 184 {
 185         struct sock *child = NULL;
 186
 187         /* Check for retransmitted REQUEST */
 188         if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
 189                 if (after48(DCCP_SKB_CB(skb)->dccpd_seq,
 190                             dccp_rsk(req)->dreq_isr)) {
 191                         struct dccp_request_sock *dreq = dccp_rsk(req);
 192
 193                         dccp_pr_debug("Retransmitted REQUEST\n");
 194                         /* Send another RESPONSE packet */
 195                         dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1);
 196                         dccp_set_seqno(&dreq->dreq_isr,
 197                                        DCCP_SKB_CB(skb)->dccpd_seq);
 198                         req->rsk_ops->rtx_syn_ack(sk, req, NULL);
 199                 }
 200                 /* Network Duplicate, discard packet */
 201                 return NULL;
 202         }
 203
 204         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
 205
 206         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
 207             dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
 208                 goto drop;
 209
 210         /* Invalid ACK */
 211         if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) {
 212                 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
 213                               "dreq_iss=%llu\n",
 214                               (unsigned long long)
 215                               DCCP_SKB_CB(skb)->dccpd_ack_seq,
 216                               (unsigned long long)
 217                               dccp_rsk(req)->dreq_iss);
 218                 goto drop;
 219         }
 220
 221         child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
 222         if (child == NULL)
 223                 goto listen_overflow;
 224
 225         /* FIXME: deal with options */
 226
 227         inet_csk_reqsk_queue_unlink(sk, req, prev);
 228         inet_csk_reqsk_queue_removed(sk, req);
 229         inet_csk_reqsk_queue_add(sk, req, child);
 230 out:
 231         return child;
 232 listen_overflow:
 233         dccp_pr_debug("listen_overflow!\n");
 234         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
 235 drop:
 236         if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
 237                 req->rsk_ops->send_reset(skb);
 238
 239         inet_csk_reqsk_queue_drop(sk, req, prev);
 240         goto out;
 241 }
 242
 243 EXPORT_SYMBOL_GPL(dccp_check_req);
 244
 245 /*
 246  *  Queue segment on the new socket if the new socket is active,
 247  *  otherwise we just shortcircuit this and continue with
 248  *  the new socket.
 249  */
 250 int dccp_child_process(struct sock *parent, struct sock *child,
 251                        struct sk_buff *skb)
 252 {
 253         int ret = 0;
 254         const int state = child->sk_state;
 255
 256         if (!sock_owned_by_user(child)) {
 257                 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
 258                                              skb->len);
 259
 260                 /* Wakeup parent, send SIGIO */
 261                 if (state == DCCP_RESPOND && child->sk_state != state)
 262                         parent->sk_data_ready(parent, 0);
 263         } else {
 264                 /* Alas, it is possible again, because we do lookup
 265                  * in main socket hash table and lock on listening
 266                  * socket does not protect us more.
 267                  */
 268                 sk_add_backlog(child, skb);
 269         }
 270
 271         bh_unlock_sock(child);
 272         sock_put(child);
 273         return ret;
 274 }
 275
 276 EXPORT_SYMBOL_GPL(dccp_child_process);