| 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_BH(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); |