/* * net/dccp/minisocks.c * * An implementation of the DCCP protocol * Arnaldo Carvalho de Melo <acme@conectiva.com.br> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/dccp.h> #include <linux/gfp.h> #include <linux/kernel.h> #include <linux/skbuff.h> #include <linux/timer.h> #include <net/sock.h> #include <net/xfrm.h> #include <net/inet_timewait_sock.h> #include "ackvec.h" #include "ccid.h" #include "dccp.h" #include "feat.h" struct inet_timewait_death_row dccp_death_row = { .sysctl_max_tw_buckets = NR_FILE * 2, .period = DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS, .death_lock = __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock), .hashinfo = &dccp_hashinfo, .tw_timer = TIMER_INITIALIZER(inet_twdr_hangman, 0, (unsigned long)&dccp_death_row), .twkill_work = __WORK_INITIALIZER(dccp_death_row.twkill_work, inet_twdr_twkill_work), /* Short-time timewait calendar */ .twcal_hand = -1, .twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0, (unsigned long)&dccp_death_row), }; EXPORT_SYMBOL_GPL(dccp_death_row); void dccp_time_wait(struct sock *sk, int state, int timeo) { struct inet_timewait_sock *tw = NULL; if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets) tw = inet_twsk_alloc(sk, state); if (tw != NULL) { const struct inet_connection_sock *icsk = inet_csk(sk); const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1); #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) if (tw->tw_family == PF_INET6) { const struct ipv6_pinfo *np = inet6_sk(sk); struct inet6_timewait_sock *tw6; tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot); tw6 = inet6_twsk((struct sock *)tw); ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr); ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr); tw->tw_ipv6only = np->ipv6only; } #endif /* Linkage updates. */ __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); /* Get the TIME_WAIT timeout firing. */ if (timeo < rto) timeo = rto; tw->tw_timeout = DCCP_TIMEWAIT_LEN; if (state == DCCP_TIME_WAIT) timeo = DCCP_TIMEWAIT_LEN; inet_twsk_schedule(tw, &dccp_death_row, timeo, DCCP_TIMEWAIT_LEN); inet_twsk_put(tw); } else { /* Sorry, if we're out of memory, just CLOSE this * socket up. We've got bigger problems than * non-graceful socket closings. */ DCCP_WARN("time wait bucket table overflow\n"); } dccp_done(sk); } struct sock *dccp_create_openreq_child(struct sock *sk, const struct request_sock *req, const struct sk_buff *skb) { /* * Step 3: Process LISTEN state * * (* Generate a new socket and switch to that socket *) * Set S := new socket for this port pair */ struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC); if (newsk != NULL) { struct dccp_request_sock *dreq = dccp_rsk(req); struct inet_connection_sock *newicsk = inet_csk(newsk); struct dccp_sock *newdp = dccp_sk(newsk); newdp->dccps_role = DCCP_ROLE_SERVER; newdp->dccps_hc_rx_ackvec = NULL; newdp->dccps_service_list = NULL; newdp->dccps_service = dreq->dreq_service; newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo; newdp->dccps_timestamp_time = dreq->dreq_timestamp_time; newicsk->icsk_rto = DCCP_TIMEOUT_INIT; INIT_LIST_HEAD(&newdp->dccps_featneg); /* * Step 3: Process LISTEN state * * Choose S.ISS (initial seqno) or set from Init Cookies * Initialize S.GAR := S.ISS * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies */ newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss; dccp_update_gss(newsk, dreq->dreq_iss); newdp->dccps_isr = dreq->dreq_isr; dccp_update_gsr(newsk, dreq->dreq_isr); /* * SWL and AWL are initially adjusted so that they are not less than * the initial Sequence Numbers received and sent, respectively: * SWL := max(GSR + 1 - floor(W/4), ISR), * AWL := max(GSS - W' + 1, ISS). * These adjustments MUST be applied only at the beginning of the * connection. */ dccp_set_seqno(&newdp->dccps_swl, max48(newdp->dccps_swl, newdp->dccps_isr)); dccp_set_seqno(&newdp->dccps_awl, max48(newdp->dccps_awl, newdp->dccps_iss)); /* * Activate features after initialising the sequence numbers, * since CCID initialisation may depend on GSS, ISR, ISS etc. */ if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) { /* It is still raw copy of parent, so invalidate * destructor and make plain sk_free() */ newsk->sk_destruct = NULL; sk_free(newsk); return NULL; } dccp_init_xmit_timers(newsk); DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS); } return newsk; } EXPORT_SYMBOL_GPL(dccp_create_openreq_child); /* * Process an incoming packet for RESPOND sockets represented * as an request_sock. */ struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct request_sock **prev) { struct sock *child = NULL; struct dccp_request_sock *dreq = dccp_rsk(req); /* Check for retransmitted REQUEST */ if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) { dccp_pr_debug("Retransmitted REQUEST\n"); dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq; /* * Send another RESPONSE packet * To protect against Request floods, increment retrans * counter (backoff, monitored by dccp_response_timer). */ req->retrans++; req->rsk_ops->rtx_syn_ack(sk, req, NULL); } /* Network Duplicate, discard packet */ return NULL; } DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR; if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK && dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK) goto drop; /* Invalid ACK */ if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) { dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " "dreq_iss=%llu\n", (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq, (unsigned long long) dreq->dreq_iss); goto drop; } if (dccp_parse_options(sk, dreq, skb)) goto drop; child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL); if (child == NULL) goto listen_overflow; inet_csk_reqsk_queue_unlink(sk, req, prev); inet_csk_reqsk_queue_removed(sk, req); inet_csk_reqsk_queue_add(sk, req, child); out: return child; listen_overflow: dccp_pr_debug("listen_overflow!\n"); DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY; drop: if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET) req->rsk_ops->send_reset(sk, skb); inet_csk_reqsk_queue_drop(sk, req, prev); goto out; } EXPORT_SYMBOL_GPL(dccp_check_req); /* * Queue segment on the new socket if the new socket is active, * otherwise we just shortcircuit this and continue with * the new socket. */ int dccp_child_process(struct sock *parent, struct sock *child, struct sk_buff *skb) { int ret = 0; const int state = child->sk_state; if (!sock_owned_by_user(child)) { ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb), skb->len); /* Wakeup parent, send SIGIO */ if (state == DCCP_RESPOND && child->sk_state != state) parent->sk_data_ready(parent, 0); } else { /* Alas, it is possible again, because we do lookup * in main socket hash table and lock on listening * socket does not protect us more. */ __sk_add_backlog(child, skb); } bh_unlock_sock(child); sock_put(child); return ret; } EXPORT_SYMBOL_GPL(dccp_child_process); void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, struct request_sock *rsk) { DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state"); } EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack); int dccp_reqsk_init(struct request_sock *req, struct dccp_sock const *dp, struct sk_buff const *skb) { struct dccp_request_sock *dreq = dccp_rsk(req); inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport; inet_rsk(req)->loc_port = dccp_hdr(skb)->dccph_dport; inet_rsk(req)->acked = 0; dreq->dreq_timestamp_echo = 0; /* inherit feature negotiation options from listening socket */ return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg); } EXPORT_SYMBOL_GPL(dccp_reqsk_init);