/*
* 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/config.h>
#include <linux/dccp.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
#include <net/sock.h>
#include <net/xfrm.h>
#include <net/inet_timewait_sock.h>
#include "ccid.h"
#include "dccp.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,
.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,
&dccp_death_row),
/* Short-time timewait calendar */
.twcal_hand = -1,
.twcal_timer = TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
(unsigned long)&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);
/* 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.
*/
LIMIT_NETDEBUG(KERN_INFO "DCCP: 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) {
const struct dccp_request_sock *dreq = dccp_rsk(req);
struct inet_connection_sock *newicsk = inet_csk(sk);
struct dccp_sock *newdp = dccp_sk(newsk);
newdp->dccps_hc_rx_ackpkts = NULL;
newdp->dccps_role = DCCP_ROLE_SERVER;
newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
if (newdp->dccps_options.dccpo_send_ack_vector) {
newdp->dccps_hc_rx_ackpkts =
dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
GFP_ATOMIC);
/*
* XXX: We're using the same CCIDs set on the parent,
* i.e. sk_clone copied the master sock and left the
* CCID pointers for this child, that is why we do the
* __ccid_get calls.
*/
if (unlikely(newdp->dccps_hc_rx_ackpkts == NULL))
goto out_free;
}
if (unlikely(ccid_hc_rx_init(newdp->dccps_hc_rx_ccid,
newsk) != 0 ||
ccid_hc_tx_init(newdp->dccps_hc_tx_ccid,
newsk) != 0)) {
dccp_ackpkts_free(newdp->dccps_hc_rx_ackpkts);
ccid_hc_rx_exit(newdp->dccps_hc_rx_ccid, newsk);
ccid_hc_tx_exit(newdp->dccps_hc_tx_ccid, newsk);
out_free:
/* It is still raw copy of parent, so invalidate
* destructor and make plain sk_free() */
newsk->sk_destruct = NULL;
sk_free(newsk);
return NULL;
}
__ccid_get(newdp->dccps_hc_rx_ccid);
__ccid_get(newdp->dccps_hc_tx_ccid);
/*
* Step 3: Process LISTEN state
*
* Choose S.ISS (initial seqno) or set from Init Cookie
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
* Cookie
*/
/* See dccp_v4_conn_request */
newdp->dccps_options.dccpo_sequence_window = req->rcv_wnd;
newdp->dccps_gar = newdp->dccps_isr = dreq->dreq_isr;
dccp_update_gsr(newsk, dreq->dreq_isr);
newdp->dccps_iss = dreq->dreq_iss;
dccp_update_gss(newsk, dreq->dreq_iss);
/*
* 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));
dccp_init_xmit_timers(newsk);
DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
}
return newsk;
}
/*
* 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;
/* Check for retransmitted REQUEST */
if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
if (after48(DCCP_SKB_CB(skb)->dccpd_seq,
dccp_rsk(req)->dreq_isr)) {
struct dccp_request_sock *dreq = dccp_rsk(req);
dccp_pr_debug("Retransmitted REQUEST\n");
/* Send another RESPONSE packet */
dccp_set_seqno(&dreq->dreq_iss, dreq->dreq_iss + 1);
dccp_set_seqno(&dreq->dreq_isr,
DCCP_SKB_CB(skb)->dccpd_seq);
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 != dccp_rsk(req)->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)
dccp_rsk(req)->dreq_iss);
goto drop;
}
child = dccp_v4_request_recv_sock(sk, skb, req, NULL);
if (child == NULL)
goto listen_overflow;
/* FIXME: deal with options */
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(skb);
inet_csk_reqsk_queue_drop(sk, req, prev);
goto out;
}
/*
* 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;
}
