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353 lines
9.5 KiB
353 lines
9.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* SCTP kernel implementation |
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* (C) Copyright IBM Corp. 2003, 2004 |
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* |
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* This file is part of the SCTP kernel implementation |
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* |
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* This file contains the code relating the chunk abstraction. |
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* |
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* Please send any bug reports or fixes you make to the |
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* email address(es): |
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* lksctp developers <[email protected]> |
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* |
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* Written or modified by: |
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* Jon Grimm <[email protected]> |
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* Sridhar Samudrala <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/net.h> |
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#include <linux/inet.h> |
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#include <linux/skbuff.h> |
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#include <linux/slab.h> |
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#include <net/sock.h> |
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#include <net/sctp/sctp.h> |
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#include <net/sctp/sm.h> |
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/* This file is mostly in anticipation of future work, but initially |
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* populate with fragment tracking for an outbound message. |
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*/ |
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/* Initialize datamsg from memory. */ |
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static void sctp_datamsg_init(struct sctp_datamsg *msg) |
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{ |
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refcount_set(&msg->refcnt, 1); |
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msg->send_failed = 0; |
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msg->send_error = 0; |
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msg->can_delay = 1; |
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msg->abandoned = 0; |
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msg->expires_at = 0; |
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INIT_LIST_HEAD(&msg->chunks); |
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} |
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/* Allocate and initialize datamsg. */ |
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static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) |
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{ |
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struct sctp_datamsg *msg; |
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msg = kmalloc(sizeof(struct sctp_datamsg), gfp); |
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if (msg) { |
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sctp_datamsg_init(msg); |
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SCTP_DBG_OBJCNT_INC(datamsg); |
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} |
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return msg; |
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} |
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void sctp_datamsg_free(struct sctp_datamsg *msg) |
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{ |
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struct sctp_chunk *chunk; |
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/* This doesn't have to be a _safe vairant because |
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* sctp_chunk_free() only drops the refs. |
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*/ |
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list_for_each_entry(chunk, &msg->chunks, frag_list) |
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sctp_chunk_free(chunk); |
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sctp_datamsg_put(msg); |
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} |
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/* Final destructruction of datamsg memory. */ |
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static void sctp_datamsg_destroy(struct sctp_datamsg *msg) |
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{ |
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struct sctp_association *asoc = NULL; |
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struct list_head *pos, *temp; |
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struct sctp_chunk *chunk; |
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struct sctp_ulpevent *ev; |
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int error, sent; |
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/* Release all references. */ |
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list_for_each_safe(pos, temp, &msg->chunks) { |
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list_del_init(pos); |
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chunk = list_entry(pos, struct sctp_chunk, frag_list); |
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if (!msg->send_failed) { |
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sctp_chunk_put(chunk); |
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continue; |
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} |
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asoc = chunk->asoc; |
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error = msg->send_error ?: asoc->outqueue.error; |
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sent = chunk->has_tsn ? SCTP_DATA_SENT : SCTP_DATA_UNSENT; |
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if (sctp_ulpevent_type_enabled(asoc->subscribe, |
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SCTP_SEND_FAILED)) { |
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ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, |
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error, GFP_ATOMIC); |
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if (ev) |
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asoc->stream.si->enqueue_event(&asoc->ulpq, ev); |
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} |
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if (sctp_ulpevent_type_enabled(asoc->subscribe, |
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SCTP_SEND_FAILED_EVENT)) { |
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ev = sctp_ulpevent_make_send_failed_event(asoc, chunk, |
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sent, error, |
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GFP_ATOMIC); |
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if (ev) |
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asoc->stream.si->enqueue_event(&asoc->ulpq, ev); |
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} |
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sctp_chunk_put(chunk); |
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} |
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SCTP_DBG_OBJCNT_DEC(datamsg); |
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kfree(msg); |
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} |
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/* Hold a reference. */ |
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static void sctp_datamsg_hold(struct sctp_datamsg *msg) |
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{ |
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refcount_inc(&msg->refcnt); |
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} |
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/* Release a reference. */ |
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void sctp_datamsg_put(struct sctp_datamsg *msg) |
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{ |
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if (refcount_dec_and_test(&msg->refcnt)) |
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sctp_datamsg_destroy(msg); |
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} |
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/* Assign a chunk to this datamsg. */ |
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static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) |
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{ |
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sctp_datamsg_hold(msg); |
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chunk->msg = msg; |
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} |
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/* A data chunk can have a maximum payload of (2^16 - 20). Break |
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* down any such message into smaller chunks. Opportunistically, fragment |
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* the chunks down to the current MTU constraints. We may get refragmented |
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* later if the PMTU changes, but it is _much better_ to fragment immediately |
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* with a reasonable guess than always doing our fragmentation on the |
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* soft-interrupt. |
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*/ |
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struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, |
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struct sctp_sndrcvinfo *sinfo, |
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struct iov_iter *from) |
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{ |
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size_t len, first_len, max_data, remaining; |
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size_t msg_len = iov_iter_count(from); |
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struct sctp_shared_key *shkey = NULL; |
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struct list_head *pos, *temp; |
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struct sctp_chunk *chunk; |
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struct sctp_datamsg *msg; |
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int err; |
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msg = sctp_datamsg_new(GFP_KERNEL); |
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if (!msg) |
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return ERR_PTR(-ENOMEM); |
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/* Note: Calculate this outside of the loop, so that all fragments |
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* have the same expiration. |
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*/ |
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if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive && |
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(SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) || |
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!SCTP_PR_POLICY(sinfo->sinfo_flags))) |
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msg->expires_at = jiffies + |
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msecs_to_jiffies(sinfo->sinfo_timetolive); |
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/* This is the biggest possible DATA chunk that can fit into |
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* the packet |
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*/ |
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max_data = asoc->frag_point; |
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if (unlikely(!max_data)) { |
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max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk), |
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sctp_datachk_len(&asoc->stream)); |
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pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%zu)", |
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__func__, asoc, max_data); |
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} |
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/* If the peer requested that we authenticate DATA chunks |
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* we need to account for bundling of the AUTH chunks along with |
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* DATA. |
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*/ |
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if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { |
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struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); |
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if (hmac_desc) |
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max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) + |
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hmac_desc->hmac_len); |
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if (sinfo->sinfo_tsn && |
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sinfo->sinfo_ssn != asoc->active_key_id) { |
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shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn); |
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if (!shkey) { |
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err = -EINVAL; |
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goto errout; |
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} |
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} else { |
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shkey = asoc->shkey; |
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} |
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} |
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/* Set first_len and then account for possible bundles on first frag */ |
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first_len = max_data; |
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/* Check to see if we have a pending SACK and try to let it be bundled |
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* with this message. Do this if we don't have any data queued already. |
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* To check that, look at out_qlen and retransmit list. |
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* NOTE: we will not reduce to account for SACK, if the message would |
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* not have been fragmented. |
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*/ |
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if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && |
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asoc->outqueue.out_qlen == 0 && |
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list_empty(&asoc->outqueue.retransmit) && |
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msg_len > max_data) |
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first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk)); |
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/* Encourage Cookie-ECHO bundling. */ |
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if (asoc->state < SCTP_STATE_COOKIE_ECHOED) |
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first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; |
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/* Account for a different sized first fragment */ |
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if (msg_len >= first_len) { |
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msg->can_delay = 0; |
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if (msg_len > first_len) |
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SCTP_INC_STATS(asoc->base.net, |
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SCTP_MIB_FRAGUSRMSGS); |
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} else { |
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/* Which may be the only one... */ |
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first_len = msg_len; |
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} |
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/* Create chunks for all DATA chunks. */ |
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for (remaining = msg_len; remaining; remaining -= len) { |
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u8 frag = SCTP_DATA_MIDDLE_FRAG; |
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if (remaining == msg_len) { |
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/* First frag, which may also be the last */ |
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frag |= SCTP_DATA_FIRST_FRAG; |
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len = first_len; |
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} else { |
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/* Middle frags */ |
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len = max_data; |
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} |
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if (len >= remaining) { |
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/* Last frag, which may also be the first */ |
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len = remaining; |
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frag |= SCTP_DATA_LAST_FRAG; |
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/* The application requests to set the I-bit of the |
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* last DATA chunk of a user message when providing |
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* the user message to the SCTP implementation. |
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*/ |
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if ((sinfo->sinfo_flags & SCTP_EOF) || |
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(sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) |
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frag |= SCTP_DATA_SACK_IMM; |
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} |
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chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, |
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GFP_KERNEL); |
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if (!chunk) { |
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err = -ENOMEM; |
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goto errout; |
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} |
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err = sctp_user_addto_chunk(chunk, len, from); |
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if (err < 0) |
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goto errout_chunk_free; |
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chunk->shkey = shkey; |
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/* Put the chunk->skb back into the form expected by send. */ |
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__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - |
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chunk->skb->data); |
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sctp_datamsg_assign(msg, chunk); |
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list_add_tail(&chunk->frag_list, &msg->chunks); |
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} |
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return msg; |
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errout_chunk_free: |
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sctp_chunk_free(chunk); |
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errout: |
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list_for_each_safe(pos, temp, &msg->chunks) { |
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list_del_init(pos); |
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chunk = list_entry(pos, struct sctp_chunk, frag_list); |
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sctp_chunk_free(chunk); |
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} |
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sctp_datamsg_put(msg); |
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return ERR_PTR(err); |
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} |
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/* Check whether this message has expired. */ |
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int sctp_chunk_abandoned(struct sctp_chunk *chunk) |
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{ |
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if (!chunk->asoc->peer.prsctp_capable) |
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return 0; |
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if (chunk->msg->abandoned) |
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return 1; |
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if (!chunk->has_tsn && |
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!(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG)) |
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return 0; |
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if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && |
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time_after(jiffies, chunk->msg->expires_at)) { |
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struct sctp_stream_out *streamout = |
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SCTP_SO(&chunk->asoc->stream, |
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chunk->sinfo.sinfo_stream); |
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if (chunk->sent_count) { |
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chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; |
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streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++; |
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} else { |
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chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; |
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streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; |
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} |
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chunk->msg->abandoned = 1; |
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return 1; |
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} else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && |
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chunk->sent_count > chunk->sinfo.sinfo_timetolive) { |
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struct sctp_stream_out *streamout = |
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SCTP_SO(&chunk->asoc->stream, |
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chunk->sinfo.sinfo_stream); |
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chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; |
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streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++; |
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chunk->msg->abandoned = 1; |
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return 1; |
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} else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && |
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chunk->msg->expires_at && |
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time_after(jiffies, chunk->msg->expires_at)) { |
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chunk->msg->abandoned = 1; |
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return 1; |
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} |
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/* PRIO policy is processed by sendmsg, not here */ |
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return 0; |
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} |
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/* This chunk (and consequently entire message) has failed in its sending. */ |
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void sctp_chunk_fail(struct sctp_chunk *chunk, int error) |
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{ |
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chunk->msg->send_failed = 1; |
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chunk->msg->send_error = error; |
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}
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