// SPDX-License-Identifier: GPL-2.0-or-later /* SCTP kernel implementation * (C) Copyright IBM Corp. 2001, 2004 * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001 Intel Corp. * Copyright (c) 2001 La Monte H.P. Yarroll * * This file is part of the SCTP kernel implementation * * This module provides the abstraction for an SCTP association. * * 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]> * Xingang Guo <[email protected]> * Hui Huang <[email protected]> * Sridhar Samudrala <[email protected]> * Daisy Chang <[email protected]> * Ryan Layer <[email protected]> * Kevin Gao <[email protected]> */ #define pr_fmt(fmt) … #include <linux/types.h> #include <linux/fcntl.h> #include <linux/poll.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/in.h> #include <net/ipv6.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> /* Forward declarations for internal functions. */ static void sctp_select_active_and_retran_path(struct sctp_association *asoc); static void sctp_assoc_bh_rcv(struct work_struct *work); static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc); static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc); /* 1st Level Abstractions. */ /* Initialize a new association from provided memory. */ static struct sctp_association *sctp_association_init( struct sctp_association *asoc, const struct sctp_endpoint *ep, const struct sock *sk, enum sctp_scope scope, gfp_t gfp) { … } /* Allocate and initialize a new association */ struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk, enum sctp_scope scope, gfp_t gfp) { … } /* Free this association if possible. There may still be users, so * the actual deallocation may be delayed. */ void sctp_association_free(struct sctp_association *asoc) { … } /* Cleanup and free up an association. */ static void sctp_association_destroy(struct sctp_association *asoc) { … } /* Change the primary destination address for the peer. */ void sctp_assoc_set_primary(struct sctp_association *asoc, struct sctp_transport *transport) { … } /* Remove a transport from an association. */ void sctp_assoc_rm_peer(struct sctp_association *asoc, struct sctp_transport *peer) { … } /* Add a transport address to an association. */ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc, const union sctp_addr *addr, const gfp_t gfp, const int peer_state) { … } /* Delete a transport address from an association. */ void sctp_assoc_del_peer(struct sctp_association *asoc, const union sctp_addr *addr) { … } /* Lookup a transport by address. */ struct sctp_transport *sctp_assoc_lookup_paddr( const struct sctp_association *asoc, const union sctp_addr *address) { … } /* Remove all transports except a give one */ void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc, struct sctp_transport *primary) { … } /* Engage in transport control operations. * Mark the transport up or down and send a notification to the user. * Select and update the new active and retran paths. */ void sctp_assoc_control_transport(struct sctp_association *asoc, struct sctp_transport *transport, enum sctp_transport_cmd command, sctp_sn_error_t error) { … } /* Hold a reference to an association. */ void sctp_association_hold(struct sctp_association *asoc) { … } /* Release a reference to an association and cleanup * if there are no more references. */ void sctp_association_put(struct sctp_association *asoc) { … } /* Allocate the next TSN, Transmission Sequence Number, for the given * association. */ __u32 sctp_association_get_next_tsn(struct sctp_association *asoc) { … } /* Compare two addresses to see if they match. Wildcard addresses * only match themselves. */ int sctp_cmp_addr_exact(const union sctp_addr *ss1, const union sctp_addr *ss2) { … } /* Return an ecne chunk to get prepended to a packet. * Note: We are sly and return a shared, prealloced chunk. FIXME: * No we don't, but we could/should. */ struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc) { … } /* * Find which transport this TSN was sent on. */ struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc, __u32 tsn) { … } /* Do delayed input processing. This is scheduled by sctp_rcv(). */ static void sctp_assoc_bh_rcv(struct work_struct *work) { … } /* This routine moves an association from its old sk to a new sk. */ void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk) { … } /* Update an association (possibly from unexpected COOKIE-ECHO processing). */ int sctp_assoc_update(struct sctp_association *asoc, struct sctp_association *new) { … } /* Update the retran path for sending a retransmitted packet. * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints: * * When there is outbound data to send and the primary path * becomes inactive (e.g., due to failures), or where the * SCTP user explicitly requests to send data to an * inactive destination transport address, before reporting * an error to its ULP, the SCTP endpoint should try to send * the data to an alternate active destination transport * address if one exists. * * When retransmitting data that timed out, if the endpoint * is multihomed, it should consider each source-destination * address pair in its retransmission selection policy. * When retransmitting timed-out data, the endpoint should * attempt to pick the most divergent source-destination * pair from the original source-destination pair to which * the packet was transmitted. * * Note: Rules for picking the most divergent source-destination * pair are an implementation decision and are not specified * within this document. * * Our basic strategy is to round-robin transports in priorities * according to sctp_trans_score() e.g., if no such * transport with state SCTP_ACTIVE exists, round-robin through * SCTP_UNKNOWN, etc. You get the picture. */ static u8 sctp_trans_score(const struct sctp_transport *trans) { … } static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1, struct sctp_transport *trans2) { … } static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr, struct sctp_transport *best) { … } void sctp_assoc_update_retran_path(struct sctp_association *asoc) { … } static void sctp_select_active_and_retran_path(struct sctp_association *asoc) { … } struct sctp_transport * sctp_assoc_choose_alter_transport(struct sctp_association *asoc, struct sctp_transport *last_sent_to) { … } void sctp_assoc_update_frag_point(struct sctp_association *asoc) { … } void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu) { … } /* Update the association's pmtu and frag_point by going through all the * transports. This routine is called when a transport's PMTU has changed. */ void sctp_assoc_sync_pmtu(struct sctp_association *asoc) { … } /* Should we send a SACK to update our peer? */ static inline bool sctp_peer_needs_update(struct sctp_association *asoc) { … } /* Increase asoc's rwnd by len and send any window update SACK if needed. */ void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len) { … } /* Decrease asoc's rwnd by len. */ void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len) { … } /* Build the bind address list for the association based on info from the * local endpoint and the remote peer. */ int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc, enum sctp_scope scope, gfp_t gfp) { … } /* Build the association's bind address list from the cookie. */ int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc, struct sctp_cookie *cookie, gfp_t gfp) { … } /* Lookup laddr in the bind address list of an association. */ int sctp_assoc_lookup_laddr(struct sctp_association *asoc, const union sctp_addr *laddr) { … } /* Set an association id for a given association */ int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp) { … } /* Free the ASCONF queue */ static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc) { … } /* Free asconf_ack cache */ static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc) { … } /* Clean up the ASCONF_ACK queue */ void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc) { … } /* Find the ASCONF_ACK whose serial number matches ASCONF */ struct sctp_chunk *sctp_assoc_lookup_asconf_ack( const struct sctp_association *asoc, __be32 serial) { … } void sctp_asconf_queue_teardown(struct sctp_association *asoc) { … }
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