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 void dccp_time_wait(struct sock *sk, int state, int timeo) 44 { 45 struct inet_timewait_sock *tw = NULL; 46 47 if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets) 48 tw = inet_twsk_alloc(sk, state); 49 50 if (tw != NULL) { 51 const struct inet_connection_sock *icsk = inet_csk(sk); 52 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); 53 54 /* Linkage updates. */ 55 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); 56 57 /* Get the TIME_WAIT timeout firing. */ 58 if (timeo < rto) 59 timeo = rto; 60 61 tw->tw_timeout = DCCP_TIMEWAIT_LEN; 62 if (state == DCCP_TIME_WAIT) 63 timeo = DCCP_TIMEWAIT_LEN; 64 65 inet_twsk_schedule(tw, &dccp_death_row, timeo, 66 DCCP_TIMEWAIT_LEN); 67 inet_twsk_put(tw); 68 } else { 69 /* Sorry, if we're out of memory, just CLOSE this 70 * socket up. We've got bigger problems than 71 * non-graceful socket closings. 72 */ 73 LIMIT_NETDEBUG(KERN_INFO "DCCP: time wait bucket " 74 "table overflow\n"); 75 } 76 77 dccp_done(sk); 78 } 79 80 struct sock *dccp_create_openreq_child(struct sock *sk, 81 const struct request_sock *req, 82 const struct sk_buff *skb) 83 { 84 /* 85 * Step 3: Process LISTEN state 86 * 87 * // Generate a new socket and switch to that socket 88 * Set S := new socket for this port pair 89 */ 90 struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); 91 92 if (newsk != NULL) { 93 const struct dccp_request_sock *dreq = dccp_rsk(req); 94 struct inet_connection_sock *newicsk = inet_csk(sk); 95 struct dccp_sock *newdp = dccp_sk(newsk); 96 97 newdp->dccps_role = DCCP_ROLE_SERVER; 98 newdp->dccps_hc_rx_ackvec = NULL; 99 newdp->dccps_service_list = NULL; 100 newdp->dccps_service = dreq->dreq_service; 101 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 102 do_gettimeofday(&newdp->dccps_epoch); 103 104 if (newdp->dccps_options.dccpo_send_ack_vector) { 105 newdp->dccps_hc_rx_ackvec = 106 dccp_ackvec_alloc(DCCP_MAX_ACKVEC_LEN, 107 GFP_ATOMIC); 108 /* 109 * XXX: We're using the same CCIDs set on the parent, 110 * i.e. sk_clone copied the master sock and left the 111 * CCID pointers for this child, that is why we do the 112 * __ccid_get calls. 113 */ 114 if (unlikely(newdp->dccps_hc_rx_ackvec == NULL)) 115 goto out_free; 116 } 117 118 if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid, 119 newsk) != 0 || 120 ccid_hc_tx_init(newdp->dccps_hc_tx_ccid, 121 newsk) != 0)) { 122 dccp_ackvec_free(newdp->dccps_hc_rx_ackvec); 123 ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk); 124 ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk); 125 out_free: 126 /* It is still raw copy of parent, so invalidate 127 * destructor and make plain sk_free() */ 128 newsk->sk_destruct = NULL; 129 sk_free(newsk); 130 return NULL; 131 } 132 133 __ccid_get(newdp->dccps_hc_rx_ccid); 134 __ccid_get(newdp->dccps_hc_tx_ccid); 135 136 /* 137 * Step 3: Process LISTEN state 138 * 139 * Choose S.ISS (initial seqno) or set from Init Cookie 140 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init 141 * Cookie 142 */ 143 144 /* See dccp_v4_conn_request */ 145 newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd; 146 147 newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr; 148 dccp_update_gsr(newsk, dreq->dreq_isr); 149 150 newdp->dccps_iss = dreq->dreq_iss; 151 dccp_update_gss(newsk, dreq->dreq_iss); 152 153 /* 154 * SWL and AWL are initially adjusted so that they are not less than 155 * the initial Sequence Numbers received and sent, respectively: 156 * SWL := max(GSR + 1 - floor(W/4), ISR), 157 * AWL := max(GSS - W' + 1, ISS). 158 * These adjustments MUST be applied only at the beginning of the 159 * connection. 160 */ 161 dccp_set_seqno(&newdp->dccps_swl, 162 max48(newdp->dccps_swl, newdp->dccps_isr)); 163 dccp_set_seqno(&newdp->dccps_awl, 164 max48(newdp->dccps_awl, newdp->dccps_iss)); 165 166 dccp_init_xmit_timers(newsk); 167 168 DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); 169 } 170 return newsk; 171 } 172 173 /* 174 * Process an incoming packet for RESPOND sockets represented 175 * as an request_sock. 176 */ 177 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 178 struct request_sock *req, 179 struct request_sock **prev) 180 { 181 struct sock *child = NULL; 182 183 /* Check for retransmitted REQUEST */ 184 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 185 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, 186 dccp_rsk(req)->dreq_isr)) { 187 struct dccp_request_sock *dreq = dccp_rsk(req); 188 189 dccp_pr_debug("Retransmitted REQUEST\n"); 190 /* Send another RESPONSE packet */ 191 dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1); 192 dccp_set_seqno(&dreq->dreq_isr, 193 DCCP_SKB_CB(skb)->dccpd_seq); 194 req->rsk_ops->rtx_syn_ack(sk, req, NULL); 195 } 196 /* Network Duplicate, discard packet */ 197 return NULL; 198 } 199 200 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 201 202 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 203 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 204 goto drop; 205 206 /* Invalid ACK */ 207 if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dccp_rsk(req)->dreq_iss) { 208 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 209 "dreq_iss=%llu\n", 210 (unsigned long long) 211 DCCP_SKB_CB(skb)->dccpd_ack_seq, 212 (unsigned long long) 213 dccp_rsk(req)->dreq_iss); 214 goto drop; 215 } 216 217 child = dccp_v4_request_recv_sock(sk, skb, req, NULL); 218 if (child == NULL) 219 goto listen_overflow; 220 221 /* FIXME: deal with options */ 222 223 inet_csk_reqsk_queue_unlink(sk, req, prev); 224 inet_csk_reqsk_queue_removed(sk, req); 225 inet_csk_reqsk_queue_add(sk, req, child); 226 out: 227 return child; 228 listen_overflow: 229 dccp_pr_debug("listen_overflow!\n"); 230 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 231 drop: 232 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 233 req->rsk_ops->send_reset(skb); 234 235 inet_csk_reqsk_queue_drop(sk, req, prev); 236 goto out; 237 } 238 239 /* 240 * Queue segment on the new socket if the new socket is active, 241 * otherwise we just shortcircuit this and continue with 242 * the new socket. 243 */ 244 int dccp_child_process(struct sock *parent, struct sock *child, 245 struct sk_buff *skb) 246 { 247 int ret = 0; 248 const int state = child->sk_state; 249 250 if (!sock_owned_by_user(child)) { 251 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 252 skb->len); 253 254 /* Wakeup parent, send SIGIO */ 255 if (state == DCCP_RESPOND && child->sk_state != state) 256 parent->sk_data_ready(parent, 0); 257 } else { 258 /* Alas, it is possible again, because we do lookup 259 * in main socket hash table and lock on listening 260 * socket does not protect us more. 261 */ 262 sk_add_backlog(child, skb); 263 } 264 265 bh_unlock_sock(child); 266 sock_put(child); 267 return ret; 268 } 269