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/dccp.h> 14 #include <linux/gfp.h> 15 #include <linux/kernel.h> 16 #include <linux/skbuff.h> 17 #include <linux/timer.h> 18 19 #include <net/sock.h> 20 #include <net/xfrm.h> 21 #include <net/inet_timewait_sock.h> 22 23 #include "ackvec.h" 24 #include "ccid.h" 25 #include "dccp.h" 26 #include "feat.h" 27 28 struct inet_timewait_death_row dccp_death_row = { 29 .sysctl_max_tw_buckets = NR_FILE * 2, 30 .hashinfo = &dccp_hashinfo, 31 }; 32 33 EXPORT_SYMBOL_GPL(dccp_death_row); 34 35 void dccp_time_wait(struct sock *sk, int state, int timeo) 36 { 37 struct inet_timewait_sock *tw; 38 39 tw = inet_twsk_alloc(sk, &dccp_death_row, state); 40 41 if (tw != NULL) { 42 const struct inet_connection_sock *icsk = inet_csk(sk); 43 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); 44 #if IS_ENABLED(CONFIG_IPV6) 45 if (tw->tw_family == PF_INET6) { 46 tw->tw_v6_daddr = sk->sk_v6_daddr; 47 tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr; 48 tw->tw_ipv6only = sk->sk_ipv6only; 49 } 50 #endif 51 52 /* Get the TIME_WAIT timeout firing. */ 53 if (timeo < rto) 54 timeo = rto; 55 56 tw->tw_timeout = DCCP_TIMEWAIT_LEN; 57 if (state == DCCP_TIME_WAIT) 58 timeo = DCCP_TIMEWAIT_LEN; 59 60 inet_twsk_schedule(tw, timeo); 61 /* Linkage updates. */ 62 __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); 63 inet_twsk_put(tw); 64 } else { 65 /* Sorry, if we're out of memory, just CLOSE this 66 * socket up. We've got bigger problems than 67 * non-graceful socket closings. 68 */ 69 DCCP_WARN("time wait bucket table overflow\n"); 70 } 71 72 dccp_done(sk); 73 } 74 75 struct sock *dccp_create_openreq_child(const struct sock *sk, 76 const struct request_sock *req, 77 const struct sk_buff *skb) 78 { 79 /* 80 * Step 3: Process LISTEN state 81 * 82 * (* Generate a new socket and switch to that socket *) 83 * Set S := new socket for this port pair 84 */ 85 struct sock *newsk = inet_csk_clone_lock(sk, req, GFP_ATOMIC); 86 87 if (newsk != NULL) { 88 struct dccp_request_sock *dreq = dccp_rsk(req); 89 struct inet_connection_sock *newicsk = inet_csk(newsk); 90 struct dccp_sock *newdp = dccp_sk(newsk); 91 92 newdp->dccps_role = DCCP_ROLE_SERVER; 93 newdp->dccps_hc_rx_ackvec = NULL; 94 newdp->dccps_service_list = NULL; 95 newdp->dccps_service = dreq->dreq_service; 96 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo; 97 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; 98 newicsk->icsk_rto = DCCP_TIMEOUT_INIT; 99 100 INIT_LIST_HEAD(&newdp->dccps_featneg); 101 /* 102 * Step 3: Process LISTEN state 103 * 104 * Choose S.ISS (initial seqno) or set from Init Cookies 105 * Initialize S.GAR := S.ISS 106 * Set S.ISR, S.GSR from packet (or Init Cookies) 107 * 108 * Setting AWL/AWH and SWL/SWH happens as part of the feature 109 * activation below, as these windows all depend on the local 110 * and remote Sequence Window feature values (7.5.2). 111 */ 112 newdp->dccps_iss = dreq->dreq_iss; 113 newdp->dccps_gss = dreq->dreq_gss; 114 newdp->dccps_gar = newdp->dccps_iss; 115 newdp->dccps_isr = dreq->dreq_isr; 116 newdp->dccps_gsr = dreq->dreq_gsr; 117 118 /* 119 * Activate features: initialise CCIDs, sequence windows etc. 120 */ 121 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) { 122 /* It is still raw copy of parent, so invalidate 123 * destructor and make plain sk_free() */ 124 newsk->sk_destruct = NULL; 125 sk_free(newsk); 126 return NULL; 127 } 128 dccp_init_xmit_timers(newsk); 129 130 __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS); 131 } 132 return newsk; 133 } 134 135 EXPORT_SYMBOL_GPL(dccp_create_openreq_child); 136 137 /* 138 * Process an incoming packet for RESPOND sockets represented 139 * as an request_sock. 140 */ 141 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 142 struct request_sock *req) 143 { 144 struct sock *child = NULL; 145 struct dccp_request_sock *dreq = dccp_rsk(req); 146 bool own_req; 147 148 /* Check for retransmitted REQUEST */ 149 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { 150 151 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) { 152 dccp_pr_debug("Retransmitted REQUEST\n"); 153 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq; 154 /* 155 * Send another RESPONSE packet 156 * To protect against Request floods, increment retrans 157 * counter (backoff, monitored by dccp_response_timer). 158 */ 159 inet_rtx_syn_ack(sk, req); 160 } 161 /* Network Duplicate, discard packet */ 162 return NULL; 163 } 164 165 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; 166 167 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && 168 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) 169 goto drop; 170 171 /* Invalid ACK */ 172 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, 173 dreq->dreq_iss, dreq->dreq_gss)) { 174 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " 175 "dreq_iss=%llu, dreq_gss=%llu\n", 176 (unsigned long long) 177 DCCP_SKB_CB(skb)->dccpd_ack_seq, 178 (unsigned long long) dreq->dreq_iss, 179 (unsigned long long) dreq->dreq_gss); 180 goto drop; 181 } 182 183 if (dccp_parse_options(sk, dreq, skb)) 184 goto drop; 185 186 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL, 187 req, &own_req); 188 if (!child) 189 goto listen_overflow; 190 191 return inet_csk_complete_hashdance(sk, child, req, own_req); 192 193 listen_overflow: 194 dccp_pr_debug("listen_overflow!\n"); 195 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; 196 drop: 197 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) 198 req->rsk_ops->send_reset(sk, skb); 199 200 inet_csk_reqsk_queue_drop(sk, req); 201 return NULL; 202 } 203 204 EXPORT_SYMBOL_GPL(dccp_check_req); 205 206 /* 207 * Queue segment on the new socket if the new socket is active, 208 * otherwise we just shortcircuit this and continue with 209 * the new socket. 210 */ 211 int dccp_child_process(struct sock *parent, struct sock *child, 212 struct sk_buff *skb) 213 { 214 int ret = 0; 215 const int state = child->sk_state; 216 217 if (!sock_owned_by_user(child)) { 218 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), 219 skb->len); 220 221 /* Wakeup parent, send SIGIO */ 222 if (state == DCCP_RESPOND && child->sk_state != state) 223 parent->sk_data_ready(parent); 224 } else { 225 /* Alas, it is possible again, because we do lookup 226 * in main socket hash table and lock on listening 227 * socket does not protect us more. 228 */ 229 __sk_add_backlog(child, skb); 230 } 231 232 bh_unlock_sock(child); 233 sock_put(child); 234 return ret; 235 } 236 237 EXPORT_SYMBOL_GPL(dccp_child_process); 238 239 void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, 240 struct request_sock *rsk) 241 { 242 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); 243 } 244 245 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); 246 247 int dccp_reqsk_init(struct request_sock *req, 248 struct dccp_sock const *dp, struct sk_buff const *skb) 249 { 250 struct dccp_request_sock *dreq = dccp_rsk(req); 251 252 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport; 253 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport); 254 inet_rsk(req)->acked = 0; 255 dreq->dreq_timestamp_echo = 0; 256 257 /* inherit feature negotiation options from listening socket */ 258 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg); 259 } 260 261 EXPORT_SYMBOL_GPL(dccp_reqsk_init); 262