// SPDX-License-Identifier: GPL-2.0-or-later /* SCTP kernel 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 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. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <[email protected]> * * Written or modified by: * La Monte H.P. Yarroll <[email protected]> * Karl Knutson <[email protected]> * Jon Grimm <[email protected]> * Hui Huang <[email protected]> * Dajiang Zhang <[email protected]> * Daisy Chang <[email protected]> * Sridhar Samudrala <[email protected]> * Ardelle Fan <[email protected]> */ #define pr_fmt(fmt) … #include <linux/skbuff.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/ip.h> #include <linux/gfp.h> #include <net/sock.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> #include <net/sctp/stream_sched.h> static int sctp_cmd_interpreter(enum sctp_event_type event_type, union sctp_subtype subtype, enum sctp_state state, struct sctp_endpoint *ep, struct sctp_association *asoc, void *event_arg, enum sctp_disposition status, struct sctp_cmd_seq *commands, gfp_t gfp); static int sctp_side_effects(enum sctp_event_type event_type, union sctp_subtype subtype, enum sctp_state state, struct sctp_endpoint *ep, struct sctp_association **asoc, void *event_arg, enum sctp_disposition status, struct sctp_cmd_seq *commands, gfp_t 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) { … } /* 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) { … } /* Helper function to do delayed processing of ECN CWR chunk. */ static void sctp_do_ecn_cwr_work(struct sctp_association *asoc, __u32 lowest_tsn) { … } /* Generate SACK if necessary. We call this at the end of a packet. */ static int sctp_gen_sack(struct sctp_association *asoc, int force, struct sctp_cmd_seq *commands) { … } /* When the T3-RTX timer expires, it calls this function to create the * relevant state machine event. */ void sctp_generate_t3_rtx_event(struct timer_list *t) { … } /* 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, enum sctp_event_timeout timeout_type) { … } static void sctp_generate_t1_cookie_event(struct timer_list *t) { … } static void sctp_generate_t1_init_event(struct timer_list *t) { … } static void sctp_generate_t2_shutdown_event(struct timer_list *t) { … } static void sctp_generate_t4_rto_event(struct timer_list *t) { … } static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t) { … } /* sctp_generate_t5_shutdown_guard_event() */ static void sctp_generate_autoclose_event(struct timer_list *t) { … } /* Generate a heart beat event. If the sock is busy, reschedule. Make * sure that the transport is still valid. */ void sctp_generate_heartbeat_event(struct timer_list *t) { … } /* Handle the timeout of the ICMP protocol unreachable timer. Trigger * the correct state machine transition that will close the association. */ void sctp_generate_proto_unreach_event(struct timer_list *t) { … } /* Handle the timeout of the RE-CONFIG timer. */ void sctp_generate_reconf_event(struct timer_list *t) { … } /* Handle the timeout of the probe timer. */ void sctp_generate_probe_event(struct timer_list *t) { … } /* Inject a SACK Timeout event into the state machine. */ static void sctp_generate_sack_event(struct timer_list *t) { … } sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = …; /* 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_cmd_seq *commands, struct sctp_association *asoc, struct sctp_transport *transport, int is_hb) { … } /* Worker routine to handle INIT command failure. */ static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands, struct sctp_association *asoc, unsigned int error) { … } /* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */ static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands, struct sctp_association *asoc, enum sctp_event_type event_type, union sctp_subtype subtype, struct sctp_chunk *chunk, unsigned int error) { … } /* 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(struct sctp_cmd_seq *commands, struct sctp_association *asoc, struct sctp_chunk *chunk, struct sctp_init_chunk *peer_init, gfp_t gfp) { … } /* Helper function to break out starting up of heartbeat timers. */ static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds, struct sctp_association *asoc) { … } static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds, struct sctp_association *asoc) { … } /* Helper function to stop any pending T3-RTX timers */ static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds, struct sctp_association *asoc) { … } /* Helper function to handle the reception of an HEARTBEAT ACK. */ static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, struct sctp_transport *t, struct sctp_chunk *chunk) { … } /* Helper function to process the process SACK command. */ static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, struct sctp_chunk *chunk) { … } /* 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(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, struct sctp_chunk *chunk) { … } /* Helper function to change the state of an association. */ static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, enum sctp_state state) { … } /* Helper function to delete an association. */ static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds, struct sctp_association *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(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, struct sctp_chunk *chunk) { … } /* Process an incoming Operation Error Chunk. */ static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds, struct sctp_association *asoc, struct sctp_chunk *chunk) { … } /* Helper function to remove the association non-primary peer * transports. */ static void sctp_cmd_del_non_primary(struct sctp_association *asoc) { … } /* Helper function to set sk_err on a 1-1 style socket. */ static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error) { … } /* Helper function to generate an association change event */ static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands, struct sctp_association *asoc, u8 state) { … } static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands, struct sctp_association *asoc) { … } /* Helper function to generate an adaptation indication event */ static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands, struct sctp_association *asoc) { … } static void sctp_cmd_t1_timer_update(struct sctp_association *asoc, enum sctp_event_timeout timer, char *name) { … } /* Send the whole message, chunk by chunk, to the outqueue. * This way the whole message is queued up and bundling if * encouraged for small fragments. */ static void sctp_cmd_send_msg(struct sctp_association *asoc, struct sctp_datamsg *msg, gfp_t gfp) { … } /* 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_sfn() … #define debug_post_sfn() … #define debug_post_sfx() … /* * 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(struct net *net, enum sctp_event_type event_type, union sctp_subtype subtype, enum sctp_state state, struct sctp_endpoint *ep, struct sctp_association *asoc, void *event_arg, gfp_t gfp) { … } /***************************************************************** * This the master state function side effect processing function. *****************************************************************/ static int sctp_side_effects(enum sctp_event_type event_type, union sctp_subtype subtype, enum sctp_state state, struct sctp_endpoint *ep, struct sctp_association **asoc, void *event_arg, enum sctp_disposition status, struct sctp_cmd_seq *commands, gfp_t gfp) { … } /******************************************************************** * 2nd Level Abstractions ********************************************************************/ /* This is the side-effect interpreter. */ static int sctp_cmd_interpreter(enum sctp_event_type event_type, union sctp_subtype subtype, enum sctp_state state, struct sctp_endpoint *ep, struct sctp_association *asoc, void *event_arg, enum sctp_disposition status, struct sctp_cmd_seq *commands, gfp_t gfp) { … }
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