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Diffstat (limited to 'net/sctp/sm_sideeffect.c')
| -rw-r--r-- | net/sctp/sm_sideeffect.c | 1395 |
1 files changed, 1395 insertions, 0 deletions
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c new file mode 100644 index 000000000000..f65fa441952f --- /dev/null +++ b/net/sctp/sm_sideeffect.c @@ -0,0 +1,1395 @@ +/* SCTP kernel reference Implementation + * (C) Copyright IBM Corp. 2001, 2004 + * Copyright (c) 1999 Cisco, Inc. + * Copyright (c) 1999-2001 Motorola, Inc. + * + * This file is part of the SCTP kernel reference Implementation + * + * These functions work with the state functions in sctp_sm_statefuns.c + * to implement that state operations. These functions implement the + * steps which require modifying existing data structures. + * + * The SCTP reference implementation 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, or (at your option) + * any later version. + * + * The SCTP reference implementation is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * ************************ + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GNU CC; see the file COPYING. If not, write to + * the Free Software Foundation, 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + * + * Please send any bug reports or fixes you make to the + * email address(es): + * lksctp developers <lksctp-developers@lists.sourceforge.net> + * + * Or submit a bug report through the following website: + * http://www.sf.net/projects/lksctp + * + * Written or modified by: + * La Monte H.P. Yarroll <piggy@acm.org> + * Karl Knutson <karl@athena.chicago.il.us> + * Jon Grimm <jgrimm@austin.ibm.com> + * Hui Huang <hui.huang@nokia.com> + * Dajiang Zhang <dajiang.zhang@nokia.com> + * Daisy Chang <daisyc@us.ibm.com> + * Sridhar Samudrala <sri@us.ibm.com> + * Ardelle Fan <ardelle.fan@intel.com> + * + * Any bugs reported given to us we will try to fix... any fixes shared will + * be incorporated into the next SCTP release. + */ + +#include <linux/skbuff.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/ip.h> +#include <net/sock.h> +#include <net/sctp/sctp.h> +#include <net/sctp/sm.h> + +static int sctp_cmd_interpreter(sctp_event_t event_type, + sctp_subtype_t subtype, + sctp_state_t state, + struct sctp_endpoint *ep, + struct sctp_association *asoc, + void *event_arg, + sctp_disposition_t status, + sctp_cmd_seq_t *commands, + int gfp); +static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, + sctp_state_t state, + struct sctp_endpoint *ep, + struct sctp_association *asoc, + void *event_arg, + sctp_disposition_t status, + sctp_cmd_seq_t *commands, + int gfp); + +/******************************************************************** + * Helper functions + ********************************************************************/ + +/* A helper function for delayed processing of INET ECN CE bit. */ +static void sctp_do_ecn_ce_work(struct sctp_association *asoc, + __u32 lowest_tsn) +{ + /* Save the TSN away for comparison when we receive CWR */ + + asoc->last_ecne_tsn = lowest_tsn; + asoc->need_ecne = 1; +} + +/* Helper function for delayed processing of SCTP ECNE chunk. */ +/* RFC 2960 Appendix A + * + * RFC 2481 details a specific bit for a sender to send in + * the header of its next outbound TCP segment to indicate to + * its peer that it has reduced its congestion window. This + * is termed the CWR bit. For SCTP the same indication is made + * by including the CWR chunk. This chunk contains one data + * element, i.e. the TSN number that was sent in the ECNE chunk. + * This element represents the lowest TSN number in the datagram + * that was originally marked with the CE bit. + */ +static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc, + __u32 lowest_tsn, + struct sctp_chunk *chunk) +{ + struct sctp_chunk *repl; + + /* Our previously transmitted packet ran into some congestion + * so we should take action by reducing cwnd and ssthresh + * and then ACK our peer that we we've done so by + * sending a CWR. + */ + + /* First, try to determine if we want to actually lower + * our cwnd variables. Only lower them if the ECNE looks more + * recent than the last response. + */ + if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) { + struct sctp_transport *transport; + + /* Find which transport's congestion variables + * need to be adjusted. + */ + transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn); + + /* Update the congestion variables. */ + if (transport) + sctp_transport_lower_cwnd(transport, + SCTP_LOWER_CWND_ECNE); + asoc->last_cwr_tsn = lowest_tsn; + } + + /* Always try to quiet the other end. In case of lost CWR, + * resend last_cwr_tsn. + */ + repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk); + + /* If we run out of memory, it will look like a lost CWR. We'll + * get back in sync eventually. + */ + return repl; +} + +/* Helper function to do delayed processing of ECN CWR chunk. */ +static void sctp_do_ecn_cwr_work(struct sctp_association *asoc, + __u32 lowest_tsn) +{ + /* Turn off ECNE getting auto-prepended to every outgoing + * packet + */ + asoc->need_ecne = 0; +} + +/* Generate SACK if necessary. We call this at the end of a packet. */ +static int sctp_gen_sack(struct sctp_association *asoc, int force, + sctp_cmd_seq_t *commands) +{ + __u32 ctsn, max_tsn_seen; + struct sctp_chunk *sack; + int error = 0; + + if (force) + asoc->peer.sack_needed = 1; + + ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map); + max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map); + + /* From 12.2 Parameters necessary per association (i.e. the TCB): + * + * Ack State : This flag indicates if the next received packet + * : is to be responded to with a SACK. ... + * : When DATA chunks are out of order, SACK's + * : are not delayed (see Section 6). + * + * [This is actually not mentioned in Section 6, but we + * implement it here anyway. --piggy] + */ + if (max_tsn_seen != ctsn) + asoc->peer.sack_needed = 1; + + /* From 6.2 Acknowledgement on Reception of DATA Chunks: + * + * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, + * an acknowledgement SHOULD be generated for at least every + * second packet (not every second DATA chunk) received, and + * SHOULD be generated within 200 ms of the arrival of any + * unacknowledged DATA chunk. ... + */ + if (!asoc->peer.sack_needed) { + /* We will need a SACK for the next packet. */ + asoc->peer.sack_needed = 1; + goto out; + } else { + if (asoc->a_rwnd > asoc->rwnd) + asoc->a_rwnd = asoc->rwnd; + sack = sctp_make_sack(asoc); + if (!sack) + goto nomem; + + asoc->peer.sack_needed = 0; + + error = sctp_outq_tail(&asoc->outqueue, sack); + + /* Stop the SACK timer. */ + sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); + } +out: + return error; +nomem: + error = -ENOMEM; + return error; +} + +/* When the T3-RTX timer expires, it calls this function to create the + * relevant state machine event. + */ +void sctp_generate_t3_rtx_event(unsigned long peer) +{ + int error; + struct sctp_transport *transport = (struct sctp_transport *) peer; + struct sctp_association *asoc = transport->asoc; + + /* Check whether a task is in the sock. */ + + sctp_bh_lock_sock(asoc->base.sk); + if (sock_owned_by_user(asoc->base.sk)) { + SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__); + + /* Try again later. */ + if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20))) + sctp_transport_hold(transport); + goto out_unlock; + } + + /* Is this transport really dead and just waiting around for + * the timer to let go of the reference? + */ + if (transport->dead) + goto out_unlock; + + /* Run through the state machine. */ + error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT, + SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX), + asoc->state, + asoc->ep, asoc, + transport, GFP_ATOMIC); + + if (error) + asoc->base.sk->sk_err = -error; + +out_unlock: + sctp_bh_unlock_sock(asoc->base.sk); + sctp_transport_put(transport); +} + +/* This is a sa interface for producing timeout events. It works + * for timeouts which use the association as their parameter. + */ +static void sctp_generate_timeout_event(struct sctp_association *asoc, + sctp_event_timeout_t timeout_type) +{ + int error = 0; + + sctp_bh_lock_sock(asoc->base.sk); + if (sock_owned_by_user(asoc->base.sk)) { + SCTP_DEBUG_PRINTK("%s:Sock is busy: timer %d\n", + __FUNCTION__, + timeout_type); + + /* Try again later. */ + if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20))) + sctp_association_hold(asoc); + goto out_unlock; + } + + /* Is this association really dead and just waiting around for + * the timer to let go of the reference? + */ + if (asoc->base.dead) + goto out_unlock; + + /* Run through the state machine. */ + error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT, + SCTP_ST_TIMEOUT(timeout_type), + asoc->state, asoc->ep, asoc, + (void *)timeout_type, GFP_ATOMIC); + + if (error) + asoc->base.sk->sk_err = -error; + +out_unlock: + sctp_bh_unlock_sock(asoc->base.sk); + sctp_association_put(asoc); +} + +static void sctp_generate_t1_cookie_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE); +} + +static void sctp_generate_t1_init_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT); +} + +static void sctp_generate_t2_shutdown_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN); +} + +static void sctp_generate_t4_rto_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO); +} + +static void sctp_generate_t5_shutdown_guard_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *)data; + sctp_generate_timeout_event(asoc, + SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD); + +} /* sctp_generate_t5_shutdown_guard_event() */ + +static void sctp_generate_autoclose_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE); +} + +/* Generate a heart beat event. If the sock is busy, reschedule. Make + * sure that the transport is still valid. + */ +void sctp_generate_heartbeat_event(unsigned long data) +{ + int error = 0; + struct sctp_transport *transport = (struct sctp_transport *) data; + struct sctp_association *asoc = transport->asoc; + + sctp_bh_lock_sock(asoc->base.sk); + if (sock_owned_by_user(asoc->base.sk)) { + SCTP_DEBUG_PRINTK("%s:Sock is busy.\n", __FUNCTION__); + + /* Try again later. */ + if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20))) + sctp_transport_hold(transport); + goto out_unlock; + } + + /* Is this structure just waiting around for us to actually + * get destroyed? + */ + if (transport->dead) + goto out_unlock; + + error = sctp_do_sm(SCTP_EVENT_T_TIMEOUT, + SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT), + asoc->state, asoc->ep, asoc, + transport, GFP_ATOMIC); + + if (error) + asoc->base.sk->sk_err = -error; + +out_unlock: + sctp_bh_unlock_sock(asoc->base.sk); + sctp_transport_put(transport); +} + +/* Inject a SACK Timeout event into the state machine. */ +static void sctp_generate_sack_event(unsigned long data) +{ + struct sctp_association *asoc = (struct sctp_association *) data; + sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK); +} + +sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = { + NULL, + sctp_generate_t1_cookie_event, + sctp_generate_t1_init_event, + sctp_generate_t2_shutdown_event, + NULL, + sctp_generate_t4_rto_event, + sctp_generate_t5_shutdown_guard_event, + sctp_generate_heartbeat_event, + sctp_generate_sack_event, + sctp_generate_autoclose_event, +}; + + +/* RFC 2960 8.2 Path Failure Detection + * + * When its peer endpoint is multi-homed, an endpoint should keep a + * error counter for each of the destination transport addresses of the + * peer endpoint. + * + * Each time the T3-rtx timer expires on any address, or when a + * HEARTBEAT sent to an idle address is not acknowledged within a RTO, + * the error counter of that destination address will be incremented. + * When the value in the error counter exceeds the protocol parameter + * 'Path.Max.Retrans' of that destination address, the endpoint should + * mark the destination transport address as inactive, and a + * notification SHOULD be sent to the upper layer. + * + */ +static void sctp_do_8_2_transport_strike(struct sctp_association *asoc, + struct sctp_transport *transport) +{ + /* The check for association's overall error counter exceeding the + * threshold is done in the state function. + */ + asoc->overall_error_count++; + + if (transport->active && + (transport->error_count++ >= transport->max_retrans)) { + SCTP_DEBUG_PRINTK("transport_strike: transport " + "IP:%d.%d.%d.%d failed.\n", + NIPQUAD(transport->ipaddr.v4.sin_addr)); + sctp_assoc_control_transport(asoc, transport, + SCTP_TRANSPORT_DOWN, + SCTP_FAILED_THRESHOLD); + } + + /* E2) For the destination address for which the timer + * expires, set RTO <- RTO * 2 ("back off the timer"). The + * maximum value discussed in rule C7 above (RTO.max) may be + * used to provide an upper bound to this doubling operation. + */ + transport->rto = min((transport->rto * 2), transport->asoc->rto_max); +} + +/* Worker routine to handle INIT command failure. */ +static void sctp_cmd_init_failed(sctp_cmd_seq_t *commands, + struct sctp_association *asoc, + unsigned error) +{ + struct sctp_ulpevent *event; + + event = sctp_ulpevent_make_assoc_change(asoc,0, SCTP_CANT_STR_ASSOC, + (__u16)error, 0, 0, + GFP_ATOMIC); + + if (event) + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(event)); + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + + /* SEND_FAILED sent later when cleaning up the association. */ + asoc->outqueue.error = error; + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); +} + +/* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */ +static void sctp_cmd_assoc_failed(sctp_cmd_seq_t *commands, + struct sctp_association *asoc, + sctp_event_t event_type, + sctp_subtype_t subtype, + struct sctp_chunk *chunk, + unsigned error) +{ + struct sctp_ulpevent *event; + + /* Cancel any partial delivery in progress. */ + sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC); + + event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST, + (__u16)error, 0, 0, + GFP_ATOMIC); + if (event) + sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, + SCTP_ULPEVENT(event)); + + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, + SCTP_STATE(SCTP_STATE_CLOSED)); + + /* Set sk_err to ECONNRESET on a 1-1 style socket. */ + if (!sctp_style(asoc->base.sk, UDP)) + asoc->base.sk->sk_err = ECONNRESET; + + /* SEND_FAILED sent later when cleaning up the association. */ + asoc->outqueue.error = error; + sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); +} + +/* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT + * inside the cookie. In reality, this is only used for INIT-ACK processing + * since all other cases use "temporary" associations and can do all + * their work in statefuns directly. + */ +static int sctp_cmd_process_init(sctp_cmd_seq_t *commands, + struct sctp_association *asoc, + struct sctp_chunk *chunk, + sctp_init_chunk_t *peer_init, int gfp) +{ + int error; + + /* We only process the init as a sideeffect in a single + * case. This is when we process the INIT-ACK. If we + * fail during INIT processing (due to malloc problems), + * just return the error and stop processing the stack. + */ + if (!sctp_process_init(asoc, chunk->chunk_hdr->type, + sctp_source(chunk), peer_init, gfp)) + error = -ENOMEM; + else + error = 0; + + return error; +} + +/* Helper function to break out starting up of heartbeat timers. */ +static void sctp_cmd_hb_timers_start(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc) +{ + struct sctp_transport *t; + struct list_head *pos; + + /* Start a heartbeat timer for each transport on the association. + * hold a reference on the transport to make sure none of + * the needed data structures go away. + */ + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + + if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t))) + sctp_transport_hold(t); + } +} + +static void sctp_cmd_hb_timers_stop(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc) +{ + struct sctp_transport *t; + struct list_head *pos; + + /* Stop all heartbeat timers. */ + + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + if (del_timer(&t->hb_timer)) + sctp_transport_put(t); + } +} + +/* Helper function to stop any pending T3-RTX timers */ +static void sctp_cmd_t3_rtx_timers_stop(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc) +{ + struct sctp_transport *t; + struct list_head *pos; + + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + if (timer_pending(&t->T3_rtx_timer) && + del_timer(&t->T3_rtx_timer)) { + sctp_transport_put(t); + } + } +} + + +/* Helper function to update the heartbeat timer. */ +static void sctp_cmd_hb_timer_update(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_transport *t) +{ + /* Update the heartbeat timer. */ + if (!mod_timer(&t->hb_timer, sctp_transport_timeout(t))) + sctp_transport_hold(t); +} + +/* Helper function to handle the reception of an HEARTBEAT ACK. */ +static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_transport *t, + struct sctp_chunk *chunk) +{ + sctp_sender_hb_info_t *hbinfo; + + /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the + * HEARTBEAT should clear the error counter of the destination + * transport address to which the HEARTBEAT was sent. + * The association's overall error count is also cleared. + */ + t->error_count = 0; + t->asoc->overall_error_count = 0; + + /* Mark the destination transport address as active if it is not so + * marked. + */ + if (!t->active) + sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP, + SCTP_HEARTBEAT_SUCCESS); + + /* The receiver of the HEARTBEAT ACK should also perform an + * RTT measurement for that destination transport address + * using the time value carried in the HEARTBEAT ACK chunk. + */ + hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; + sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at)); +} + +/* Helper function to do a transport reset at the expiry of the hearbeat + * timer. + */ +static void sctp_cmd_transport_reset(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_transport *t) +{ + sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE); + + /* Mark one strike against a transport. */ + sctp_do_8_2_transport_strike(asoc, t); +} + +/* Helper function to process the process SACK command. */ +static int sctp_cmd_process_sack(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_sackhdr *sackh) +{ + int err; + + if (sctp_outq_sack(&asoc->outqueue, sackh)) { + /* There are no more TSNs awaiting SACK. */ + err = sctp_do_sm(SCTP_EVENT_T_OTHER, + SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN), + asoc->state, asoc->ep, asoc, NULL, + GFP_ATOMIC); + } else { + /* Windows may have opened, so we need + * to check if we have DATA to transmit + */ + err = sctp_outq_flush(&asoc->outqueue, 0); + } + + return err; +} + +/* Helper function to set the timeout value for T2-SHUTDOWN timer and to set + * the transport for a shutdown chunk. + */ +static void sctp_cmd_setup_t2(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_chunk *chunk) +{ + struct sctp_transport *t; + + t = sctp_assoc_choose_shutdown_transport(asoc); + asoc->shutdown_last_sent_to = t; + asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto; + chunk->transport = t; +} + +/* Helper function to change the state of an association. */ +static void sctp_cmd_new_state(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + sctp_state_t state) +{ + struct sock *sk = asoc->base.sk; + + asoc->state = state; + + if (sctp_style(sk, TCP)) { + /* Change the sk->sk_state of a TCP-style socket that has + * sucessfully completed a connect() call. + */ + if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED)) + sk->sk_state = SCTP_SS_ESTABLISHED; + + /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */ + if (sctp_state(asoc, SHUTDOWN_RECEIVED) && + sctp_sstate(sk, ESTABLISHED)) + sk->sk_shutdown |= RCV_SHUTDOWN; + } + + if (sctp_state(asoc, ESTABLISHED) || + sctp_state(asoc, CLOSED) || + sctp_state(asoc, SHUTDOWN_RECEIVED)) { + /* Wake up any processes waiting in the asoc's wait queue in + * sctp_wait_for_connect() or sctp_wait_for_sndbuf(). + */ + if (waitqueue_active(&asoc->wait)) + wake_up_interruptible(&asoc->wait); + + /* Wake up any processes waiting in the sk's sleep queue of + * a TCP-style or UDP-style peeled-off socket in + * sctp_wait_for_accept() or sctp_wait_for_packet(). + * For a UDP-style socket, the waiters are woken up by the + * notifications. + */ + if (!sctp_style(sk, UDP)) + sk->sk_state_change(sk); + } +} + +/* Helper function to delete an association. */ +static void sctp_cmd_delete_tcb(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc) +{ + struct sock *sk = asoc->base.sk; + + /* If it is a non-temporary association belonging to a TCP-style + * listening socket that is not closed, do not free it so that accept() + * can pick it up later. + */ + if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) && + (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK)) + return; + + sctp_unhash_established(asoc); + sctp_association_free(asoc); +} + +/* + * ADDIP Section 4.1 ASCONF Chunk Procedures + * A4) Start a T-4 RTO timer, using the RTO value of the selected + * destination address (we use active path instead of primary path just + * because primary path may be inactive. + */ +static void sctp_cmd_setup_t4(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_chunk *chunk) +{ + struct sctp_transport *t; + + t = asoc->peer.active_path; + asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto; + chunk->transport = t; +} + +/* Process an incoming Operation Error Chunk. */ +static void sctp_cmd_process_operr(sctp_cmd_seq_t *cmds, + struct sctp_association *asoc, + struct sctp_chunk *chunk) +{ + struct sctp_operr_chunk *operr_chunk; + struct sctp_errhdr *err_hdr; + + operr_chunk = (struct sctp_operr_chunk *)chunk->chunk_hdr; + err_hdr = &operr_chunk->err_hdr; + + switch (err_hdr->cause) { + case SCTP_ERROR_UNKNOWN_CHUNK: + { + struct sctp_chunkhdr *unk_chunk_hdr; + + unk_chunk_hdr = (struct sctp_chunkhdr *)err_hdr->variable; + switch (unk_chunk_hdr->type) { + /* ADDIP 4.1 A9) If the peer responds to an ASCONF with an + * ERROR chunk reporting that it did not recognized the ASCONF + * chunk type, the sender of the ASCONF MUST NOT send any + * further ASCONF chunks and MUST stop its T-4 timer. + */ + case SCTP_CID_ASCONF: + asoc->peer.asconf_capable = 0; + sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP, + SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); + break; + default: + break; + } + break; + } + default: + break; + } +} + +/* Process variable FWDTSN chunk information. */ +static void sctp_cmd_process_fwdtsn(struct sctp_ulpq *ulpq, + struct sctp_chunk *chunk) +{ + struct sctp_fwdtsn_skip *skip; + /* Walk through all the skipped SSNs */ + sctp_walk_fwdtsn(skip, chunk) { + sctp_ulpq_skip(ulpq, ntohs(skip->stream), ntohs(skip->ssn)); + } + + return; +} + +/* Helper function to remove the association non-primary peer + * transports. + */ +static void sctp_cmd_del_non_primary(struct sctp_association *asoc) +{ + struct sctp_transport *t; + struct list_head *pos; + struct list_head *temp; + + list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, transports); + if (!sctp_cmp_addr_exact(&t->ipaddr, + &asoc->peer.primary_addr)) { + sctp_assoc_del_peer(asoc, &t->ipaddr); + } + } + + return; +} + +/* These three macros allow us to pull the debugging code out of the + * main flow of sctp_do_sm() to keep attention focused on the real + * functionality there. + */ +#define DEBUG_PRE \ + SCTP_DEBUG_PRINTK("sctp_do_sm prefn: " \ + "ep %p, %s, %s, asoc %p[%s], %s\n", \ + ep, sctp_evttype_tbl[event_type], \ + (*debug_fn)(subtype), asoc, \ + sctp_state_tbl[state], state_fn->name) + +#define DEBUG_POST \ + SCTP_DEBUG_PRINTK("sctp_do_sm postfn: " \ + "asoc %p, status: %s\n", \ + asoc, sctp_status_tbl[status]) + +#define DEBUG_POST_SFX \ + SCTP_DEBUG_PRINTK("sctp_do_sm post sfx: error %d, asoc %p[%s]\n", \ + error, asoc, \ + sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \ + sctp_assoc2id(asoc)))?asoc->state:SCTP_STATE_CLOSED]) + +/* + * This is the master state machine processing function. + * + * If you want to understand all of lksctp, this is a + * good place to start. + */ +int sctp_do_sm(sctp_event_t event_type, sctp_subtype_t subtype, + sctp_state_t state, + struct sctp_endpoint *ep, + struct sctp_association *asoc, + void *event_arg, + int gfp) +{ + sctp_cmd_seq_t commands; + const sctp_sm_table_entry_t *state_fn; + sctp_disposition_t status; + int error = 0; + typedef const char *(printfn_t)(sctp_subtype_t); + + static printfn_t *table[] = { + NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname, + }; + printfn_t *debug_fn __attribute__ ((unused)) = table[event_type]; + + /* Look up the state function, run it, and then process the + * side effects. These three steps are the heart of lksctp. + */ + state_fn = sctp_sm_lookup_event(event_type, state, subtype); + + sctp_init_cmd_seq(&commands); + + DEBUG_PRE; + status = (*state_fn->fn)(ep, asoc, subtype, event_arg, &commands); + DEBUG_POST; + + error = sctp_side_effects(event_type, subtype, state, + ep, asoc, event_arg, status, + &commands, gfp); + DEBUG_POST_SFX; + + return error; +} + +#undef DEBUG_PRE +#undef DEBUG_POST + +/***************************************************************** + * This the master state function side effect processing function. + *****************************************************************/ +static int sctp_side_effects(sctp_event_t event_type, sctp_subtype_t subtype, + sctp_state_t state, + struct sctp_endpoint *ep, + struct sctp_association *asoc, + void *event_arg, + sctp_disposition_t status, + sctp_cmd_seq_t *commands, + int gfp) +{ + int error; + + /* FIXME - Most of the dispositions left today would be categorized + * as "exceptional" dispositions. For those dispositions, it + * may not be proper to run through any of the commands at all. + * For example, the command interpreter might be run only with + * disposition SCTP_DISPOSITION_CONSUME. + */ + if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state, + ep, asoc, + event_arg, status, + commands, gfp))) + goto bail; + + switch (status) { + case SCTP_DISPOSITION_DISCARD: + SCTP_DEBUG_PRINTK("Ignored sctp protocol event - state %d, " + "event_type %d, event_id %d\n", + state, event_type, subtype.chunk); + break; + + case SCTP_DISPOSITION_NOMEM: + /* We ran out of memory, so we need to discard this + * packet. + */ + /* BUG--we should now recover some memory, probably by + * reneging... + */ + error = -ENOMEM; + break; + + case SCTP_DISPOSITION_DELETE_TCB: + /* This should now be a command. */ + break; + + case SCTP_DISPOSITION_CONSUME: + case SCTP_DISPOSITION_ABORT: + /* + * We should no longer have much work to do here as the + * real work has been done as explicit commands above. + */ + break; + + case SCTP_DISPOSITION_VIOLATION: + printk(KERN_ERR "sctp protocol violation state %d " + "chunkid %d\n", state, subtype.chunk); + break; + + case SCTP_DISPOSITION_NOT_IMPL: + printk(KERN_WARNING "sctp unimplemented feature in state %d, " + "event_type %d, event_id %d\n", + state, event_type, subtype.chunk); + break; + + case SCTP_DISPOSITION_BUG: + printk(KERN_ERR "sctp bug in state %d, " + "event_type %d, event_id %d\n", + state, event_type, subtype.chunk); + BUG(); + break; + + default: + printk(KERN_ERR "sctp impossible disposition %d " + "in state %d, event_type %d, event_id %d\n", + status, state, event_type, subtype.chunk); + BUG(); + break; + }; + +bail: + return error; +} + +/******************************************************************** + * 2nd Level Abstractions + ********************************************************************/ + +/* This is the side-effect interpreter. */ +static int sctp_cmd_interpreter(sctp_event_t event_type, + sctp_subtype_t subtype, + sctp_state_t state, + struct sctp_endpoint *ep, + struct sctp_association *asoc, + void *event_arg, + sctp_disposition_t status, + sctp_cmd_seq_t *commands, + int gfp) +{ + int error = 0; + int force; + sctp_cmd_t *cmd; + struct sctp_chunk *new_obj; + struct sctp_chunk *chunk = NULL; + struct sctp_packet *packet; + struct list_head *pos; + struct timer_list *timer; + unsigned long timeout; + struct sctp_transport *t; + struct sctp_sackhdr sackh; + int local_cork = 0; + + if (SCTP_EVENT_T_TIMEOUT != event_type) + chunk = (struct sctp_chunk *) event_arg; + + /* Note: This whole file is a huge candidate for rework. + * For example, each command could either have its own handler, so + * the loop would look like: + * while (cmds) + * cmd->handle(x, y, z) + * --jgrimm + */ + while (NULL != (cmd = sctp_next_cmd(commands))) { + switch (cmd->verb) { + case SCTP_CMD_NOP: + /* Do nothing. */ + break; + + case SCTP_CMD_NEW_ASOC: + /* Register a new association. */ + if (local_cork) { + sctp_outq_uncork(&asoc->outqueue); + local_cork = 0; + } + asoc = cmd->obj.ptr; + /* Register with the endpoint. */ + sctp_endpoint_add_asoc(ep, asoc); + sctp_hash_established(asoc); + break; + + case SCTP_CMD_UPDATE_ASSOC: + sctp_assoc_update(asoc, cmd->obj.ptr); + break; + + case SCTP_CMD_PURGE_OUTQUEUE: + sctp_outq_teardown(&asoc->outqueue); + break; + + case SCTP_CMD_DELETE_TCB: + if (local_cork) { + sctp_outq_uncork(&asoc->outqueue); + local_cork = 0; + } + /* Delete the current association. */ + sctp_cmd_delete_tcb(commands, asoc); + asoc = NULL; + break; + + case SCTP_CMD_NEW_STATE: + /* Enter a new state. */ + sctp_cmd_new_state(commands, asoc, cmd->obj.state); + break; + + case SCTP_CMD_REPORT_TSN: + /* Record the arrival of a TSN. */ + sctp_tsnmap_mark(&asoc->peer.tsn_map, cmd->obj.u32); + break; + + case SCTP_CMD_REPORT_FWDTSN: + /* Move the Cumulattive TSN Ack ahead. */ + sctp_tsnmap_skip(&asoc->peer.tsn_map, cmd->obj.u32); + + /* Abort any in progress partial delivery. */ + sctp_ulpq_abort_pd(&asoc->ulpq, GFP_ATOMIC); + break; + + case SCTP_CMD_PROCESS_FWDTSN: + sctp_cmd_process_fwdtsn(&asoc->ulpq, cmd->obj.ptr); + break; + + case SCTP_CMD_GEN_SACK: + /* Generate a Selective ACK. + * The argument tells us whether to just count + * the packet and MAYBE generate a SACK, or + * force a SACK out. + */ + force = cmd->obj.i32; + error = sctp_gen_sack(asoc, force, commands); + break; + + case SCTP_CMD_PROCESS_SACK: + /* Process an inbound SACK. */ + error = sctp_cmd_process_sack(commands, asoc, + cmd->obj.ptr); + break; + + case SCTP_CMD_GEN_INIT_ACK: + /* Generate an INIT ACK chunk. */ + new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC, + 0); + if (!new_obj) + goto nomem; + + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(new_obj)); + break; + + case SCTP_CMD_PEER_INIT: + /* Process a unified INIT from the peer. + * Note: Only used during INIT-ACK processing. If + * there is an error just return to the outter + * layer which will bail. + */ + error = sctp_cmd_process_init(commands, asoc, chunk, + cmd->obj.ptr, gfp); + break; + + case SCTP_CMD_GEN_COOKIE_ECHO: + /* Generate a COOKIE ECHO chunk. */ + new_obj = sctp_make_cookie_echo(asoc, chunk); + if (!new_obj) { + if (cmd->obj.ptr) + sctp_chunk_free(cmd->obj.ptr); + goto nomem; + } + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(new_obj)); + + /* If there is an ERROR chunk to be sent along with + * the COOKIE_ECHO, send it, too. + */ + if (cmd->obj.ptr) + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(cmd->obj.ptr)); + + /* FIXME - Eventually come up with a cleaner way to + * enabling COOKIE-ECHO + DATA bundling during + * multihoming stale cookie scenarios, the following + * command plays with asoc->peer.retran_path to + * avoid the problem of sending the COOKIE-ECHO and + * DATA in different paths, which could result + * in the association being ABORTed if the DATA chunk + * is processed first by the server. Checking the + * init error counter simply causes this command + * to be executed only during failed attempts of + * association establishment. + */ + if ((asoc->peer.retran_path != + asoc->peer.primary_path) && + (asoc->counters[SCTP_COUNTER_INIT_ERROR] > 0)) { + sctp_add_cmd_sf(commands, + SCTP_CMD_FORCE_PRIM_RETRAN, + SCTP_NULL()); + } + + break; + + case SCTP_CMD_GEN_SHUTDOWN: + /* Generate SHUTDOWN when in SHUTDOWN_SENT state. + * Reset error counts. + */ + asoc->overall_error_count = 0; + + /* Generate a SHUTDOWN chunk. */ + new_obj = sctp_make_shutdown(asoc, chunk); + if (!new_obj) + goto nomem; + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(new_obj)); + break; + + case SCTP_CMD_CHUNK_ULP: + /* Send a chunk to the sockets layer. */ + SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n", + "chunk_up:", cmd->obj.ptr, + "ulpq:", &asoc->ulpq); + sctp_ulpq_tail_data(&asoc->ulpq, cmd->obj.ptr, + GFP_ATOMIC); + break; + + case SCTP_CMD_EVENT_ULP: + /* Send a notification to the sockets layer. */ + SCTP_DEBUG_PRINTK("sm_sideff: %s %p, %s %p.\n", + "event_up:",cmd->obj.ptr, + "ulpq:",&asoc->ulpq); + sctp_ulpq_tail_event(&asoc->ulpq, cmd->obj.ptr); + break; + + case SCTP_CMD_REPLY: + /* If an caller has not already corked, do cork. */ + if (!asoc->outqueue.cork) { + sctp_outq_cork(&asoc->outqueue); + local_cork = 1; + } + /* Send a chunk to our peer. */ + error = sctp_outq_tail(&asoc->outqueue, cmd->obj.ptr); + break; + + case SCTP_CMD_SEND_PKT: + /* Send a full packet to our peer. */ + packet = cmd->obj.ptr; + sctp_packet_transmit(packet); + sctp_ootb_pkt_free(packet); + break; + + case SCTP_CMD_RETRAN: + /* Mark a transport for retransmission. */ + sctp_retransmit(&asoc->outqueue, cmd->obj.transport, + SCTP_RTXR_T3_RTX); + break; + + case SCTP_CMD_TRANSMIT: + /* Kick start transmission. */ + error = sctp_outq_uncork(&asoc->outqueue); + local_cork = 0; + break; + + case SCTP_CMD_ECN_CE: + /* Do delayed CE processing. */ + sctp_do_ecn_ce_work(asoc, cmd->obj.u32); + break; + + case SCTP_CMD_ECN_ECNE: + /* Do delayed ECNE processing. */ + new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32, + chunk); + if (new_obj) + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, + SCTP_CHUNK(new_obj)); + break; + + case SCTP_CMD_ECN_CWR: + /* Do delayed CWR processing. */ + sctp_do_ecn_cwr_work(asoc, cmd->obj.u32); + break; + + case SCTP_CMD_SETUP_T2: + sctp_cmd_setup_t2(commands, asoc, cmd->obj.ptr); + break; + + case SCTP_CMD_TIMER_START: + timer = &asoc->timers[cmd->obj.to]; + timeout = asoc->timeouts[cmd->obj.to]; + if (!timeout) + BUG(); + + timer->expires = jiffies + timeout; + sctp_association_hold(asoc); + add_timer(timer); + break; + + case SCTP_CMD_TIMER_RESTART: + timer = &asoc->timers[cmd->obj.to]; + timeout = asoc->timeouts[cmd->obj.to]; + if (!mod_timer(timer, jiffies + timeout)) + sctp_association_hold(asoc); + break; + + case SCTP_CMD_TIMER_STOP: + timer = &asoc->timers[cmd->obj.to]; + if (timer_pending(timer) && del_timer(timer)) + sctp_association_put(asoc); + break; + + case SCTP_CMD_INIT_RESTART: + /* Do the needed accounting and updates + * associated with restarting an initialization + * timer. + */ + asoc->counters[SCTP_COUNTER_INIT_ERROR]++; + asoc->timeouts[cmd->obj.to] *= 2; + if (asoc->timeouts[cmd->obj.to] > + asoc->max_init_timeo) { + asoc->timeouts[cmd->obj.to] = + asoc->max_init_timeo; + } + + /* If we've sent any data bundled with + * COOKIE-ECHO we need to resend. + */ + list_for_each(pos, &asoc->peer.transport_addr_list) { + t = list_entry(pos, struct sctp_transport, + transports); + sctp_retransmit_mark(&asoc->outqueue, t, 0); + } + + sctp_add_cmd_sf(commands, + SCTP_CMD_TIMER_RESTART, + SCTP_TO(cmd->obj.to)); + break; + + case SCTP_CMD_INIT_FAILED: + sctp_cmd_init_failed(commands, asoc, cmd->obj.u32); + break; + + case SCTP_CMD_ASSOC_FAILED: + sctp_cmd_assoc_failed(commands, asoc, event_type, + subtype, chunk, cmd->obj.u32); + break; + + case SCTP_CMD_COUNTER_INC: + asoc->counters[cmd->obj.counter]++; + break; + + case SCTP_CMD_COUNTER_RESET: + asoc->counters[cmd->obj.counter] = 0; + break; + + case SCTP_CMD_REPORT_DUP: + sctp_tsnmap_mark_dup(&asoc->peer.tsn_map, + cmd->obj.u32); + break; + + case SCTP_CMD_REPORT_BAD_TAG: + SCTP_DEBUG_PRINTK("vtag mismatch!\n"); + break; + + case SCTP_CMD_STRIKE: + /* Mark one strike against a transport. */ + sctp_do_8_2_transport_strike(asoc, cmd->obj.transport); + break; + + case SCTP_CMD_TRANSPORT_RESET: + t = cmd->obj.transport; + sctp_cmd_transport_reset(commands, asoc, t); + break; + + case SCTP_CMD_TRANSPORT_ON: + t = cmd->obj.transport; + sctp_cmd_transport_on(commands, asoc, t, chunk); + break; + + case SCTP_CMD_HB_TIMERS_START: + sctp_cmd_hb_timers_start(commands, asoc); + break; + + case SCTP_CMD_HB_TIMER_UPDATE: + t = cmd->obj.transport; + sctp_cmd_hb_timer_update(commands, asoc, t); + break; + + case SCTP_CMD_HB_TIMERS_STOP: + sctp_cmd_hb_timers_stop(commands, asoc); + break; + + case SCTP_CMD_REPORT_ERROR: + error = cmd->obj.error; + break; + + case SCTP_CMD_PROCESS_CTSN: + /* Dummy up a SACK for processing. */ + sackh.cum_tsn_ack = cmd->obj.u32; + sackh.a_rwnd = 0; + sackh.num_gap_ack_blocks = 0; + sackh.num_dup_tsns = 0; + sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, + SCTP_SACKH(&sackh)); + break; + + case SCTP_CMD_DISCARD_PACKET: + /* We need to discard the whole packet. */ + chunk->pdiscard = 1; + break; + + case SCTP_CMD_RTO_PENDING: + t = cmd->obj.transport; + t->rto_pending = 1; + break; + + case SCTP_CMD_PART_DELIVER: + sctp_ulpq_partial_delivery(&asoc->ulpq, cmd->obj.ptr, + GFP_ATOMIC); + break; + + case SCTP_CMD_RENEGE: + sctp_ulpq_renege(&asoc->ulpq, cmd->obj.ptr, + GFP_ATOMIC); + break; + + case SCTP_CMD_SETUP_T4: + sctp_cmd_setup_t4(commands, asoc, cmd->obj.ptr); + break; + + case SCTP_CMD_PROCESS_OPERR: + sctp_cmd_process_operr(commands, asoc, chunk); + break; + case SCTP_CMD_CLEAR_INIT_TAG: + asoc->peer.i.init_tag = 0; + break; + case SCTP_CMD_DEL_NON_PRIMARY: + sctp_cmd_del_non_primary(asoc); + break; + case SCTP_CMD_T3_RTX_TIMERS_STOP: + sctp_cmd_t3_rtx_timers_stop(commands, asoc); + break; + case SCTP_CMD_FORCE_PRIM_RETRAN: + t = asoc->peer.retran_path; + asoc->peer.retran_path = asoc->peer.primary_path; + error = sctp_outq_uncork(&asoc->outqueue); + local_cork = 0; + asoc->peer.retran_path = t; + break; + default: + printk(KERN_WARNING "Impossible command: %u, %p\n", + cmd->verb, cmd->obj.ptr); + break; + }; + if (error) + break; + } + +out: + if (local_cork) + sctp_outq_uncork(&asoc->outqueue); + return error; +nomem: + error = -ENOMEM; + goto out; +} + |