sm_sideeffect.c

在linux环境下的流控制传输协议（sctp）的源代码

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,
				gfp_t 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);

			/* purge the fragmentation queue */
			sctp_ulpq_reasm_flushtsn(&asoc->ulpq, 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->init_err_counter > 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_T1_RETRAN:
			/* Mark a transport for retransmission.  */
			sctp_retransmit(&asoc->outqueue, cmd->obj.transport,
					SCTP_RTXR_T1_RTX);
			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];
			BUG_ON(!timeout);

			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_CHOOSE_TRANSPORT:
			chunk = cmd->obj.ptr;
			t = sctp_assoc_choose_init_transport(asoc);
			asoc->init_last_sent_to = t;
			chunk->transport = t;
			t->init_sent_count++;
			break;

		case SCTP_CMD_INIT_RESTART:
			/* Do the needed accounting and updates
			 * associated with restarting an initialization
			 * timer. Only multiply the timeout by two if
			 * all transports have been tried at the current
			 * timeout.
			 */
			t = asoc->init_last_sent_to;
			asoc->init_err_counter++;

			if (t->init_sent_count > (asoc->init_cycle + 1)) {
				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] *= 2;
				if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] >
				    asoc->max_init_timeo) {
					asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
						asoc->max_init_timeo;
				}
				asoc->init_cycle++;
				SCTP_DEBUG_PRINTK(
					"T1 INIT Timeout adjustment"
					" init_err_counter: %d"
					" cycle: %d"
					" timeout: %ld\n",
					asoc->init_err_counter,
					asoc->init_cycle,
					asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT]);
			}

			sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
			break;

		case SCTP_CMD_COOKIEECHO_RESTART:
			/* Do the needed accounting and updates
			 * associated with restarting an initialization
			 * timer. Only multiply the timeout by two if
			 * all transports have been tried at the current
			 * timeout.
			 */
			asoc->init_err_counter++;

			asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] *= 2;
			if (asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] >
			    asoc->max_init_timeo) {
				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
					asoc->max_init_timeo;
			}
			SCTP_DEBUG_PRINTK(
				"T1 COOKIE Timeout adjustment"
				" init_err_counter: %d"
				" timeout: %ld\n",
				asoc->init_err_counter,
				asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE]);

			/* 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,
					    SCTP_RTXR_T1_RTX);
			}

			sctp_add_cmd_sf(commands,
					SCTP_CMD_TIMER_RESTART,
					SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
			break;

		case SCTP_CMD_INIT_FAILED:
			sctp_cmd_init_failed(commands, asoc, cmd->obj.err);
			break;

		case SCTP_CMD_ASSOC_FAILED:
			sctp_cmd_assoc_failed(commands, asoc, event_type,
					      subtype, chunk, cmd->obj.err);
			break;

		case SCTP_CMD_INIT_COUNTER_INC:
			asoc->init_err_counter++;
			break;

		case SCTP_CMD_INIT_COUNTER_RESET:
			asoc->init_err_counter = 0;
			asoc->init_cycle = 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.be32;
			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;
		case SCTP_CMD_SET_SK_ERR:
			sctp_cmd_set_sk_err(asoc, cmd->obj.error);
			break;
		case SCTP_CMD_ASSOC_CHANGE:
			sctp_cmd_assoc_change(commands, asoc,
					      cmd->obj.u8);
			break;
		case SCTP_CMD_ADAPTATION_IND:
			sctp_cmd_adaptation_ind(commands, asoc);
			break;

		case SCTP_CMD_ASSOC_SHKEY:
			error = sctp_auth_asoc_init_active_key(asoc,
						GFP_ATOMIC);
			break;
		case SCTP_CMD_UPDATE_INITTAG:
			asoc->peer.i.init_tag = cmd->obj.u32;
			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;
}