/* * 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, .hashinfo = &dccp_hashinfo, }; EXPORT_SYMBOL_GPL(dccp_death_row); void dccp_time_wait(struct sock *sk, int state, int timeo) { struct inet_timewait_sock *tw; tw = inet_twsk_alloc(sk, &dccp_death_row, 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 IS_ENABLED(CONFIG_IPV6) if (tw->tw_family == PF_INET6) { tw->tw_v6_daddr = sk->sk_v6_daddr; tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr; tw->tw_ipv6only = sk->sk_ipv6only; } #endif /* 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, timeo); /* Linkage updates. */ __inet_twsk_hashdance(tw, sk, &dccp_hashinfo); 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(const 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_lock(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 from packet (or Init Cookies) * * Setting AWL/AWH and SWL/SWH happens as part of the feature * activation below, as these windows all depend on the local * and remote Sequence Window feature values (7.5.2). */ newdp->dccps_iss = dreq->dreq_iss; newdp->dccps_gss = dreq->dreq_gss; newdp->dccps_gar = newdp->dccps_iss; newdp->dccps_isr = dreq->dreq_isr; newdp->dccps_gsr = dreq->dreq_gsr; /* * Activate features: initialise CCIDs, sequence windows 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(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 sock *child = NULL; struct dccp_request_sock *dreq = dccp_rsk(req); bool own_req; /* Check for retransmitted REQUEST */ if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) { if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) { dccp_pr_debug("Retransmitted REQUEST\n"); dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq; /* * Send another RESPONSE packet * To protect against Request floods, increment retrans * counter (backoff, monitored by dccp_response_timer). */ inet_rtx_syn_ack(sk, req); } /* 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 (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, dreq->dreq_iss, dreq->dreq_gss)) { dccp_pr_debug("Invalid ACK number: ack_seq=%llu, " "dreq_iss=%llu, dreq_gss=%llu\n", (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq, (unsigned long long) dreq->dreq_iss, (unsigned long long) dreq->dreq_gss); 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, req, &own_req); if (!child) goto listen_overflow; return inet_csk_complete_hashdance(sk, child, req, own_req); 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); return NULL; } 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); } 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(const 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)->ir_rmt_port = dccp_hdr(skb)->dccph_sport; inet_rsk(req)->ir_num = ntohs(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);