diff options
Diffstat (limited to 'net/sctp/ulpqueue.c')
| -rw-r--r-- | net/sctp/ulpqueue.c | 1144 |
1 files changed, 1144 insertions, 0 deletions
diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c new file mode 100644 index 000000000..ce469d648 --- /dev/null +++ b/net/sctp/ulpqueue.c @@ -0,0 +1,1144 @@ +/* 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 Nokia, Inc. + * Copyright (c) 2001 La Monte H.P. Yarroll + * + * This abstraction carries sctp events to the ULP (sockets). + * + * This SCTP 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. + * + * This SCTP 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, see + * <http://www.gnu.org/licenses/>. + * + * Please send any bug reports or fixes you make to the + * email address(es): + * lksctp developers <linux-sctp@vger.kernel.org> + * + * Written or modified by: + * Jon Grimm <jgrimm@us.ibm.com> + * La Monte H.P. Yarroll <piggy@acm.org> + * Sridhar Samudrala <sri@us.ibm.com> + */ + +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/skbuff.h> +#include <net/sock.h> +#include <net/busy_poll.h> +#include <net/sctp/structs.h> +#include <net/sctp/sctp.h> +#include <net/sctp/sm.h> + +/* Forward declarations for internal helpers. */ +static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *); +static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *, + struct sctp_ulpevent *); +static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq); + +/* 1st Level Abstractions */ + +/* Initialize a ULP queue from a block of memory. */ +struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq, + struct sctp_association *asoc) +{ + memset(ulpq, 0, sizeof(struct sctp_ulpq)); + + ulpq->asoc = asoc; + skb_queue_head_init(&ulpq->reasm); + skb_queue_head_init(&ulpq->lobby); + ulpq->pd_mode = 0; + + return ulpq; +} + + +/* Flush the reassembly and ordering queues. */ +void sctp_ulpq_flush(struct sctp_ulpq *ulpq) +{ + struct sk_buff *skb; + struct sctp_ulpevent *event; + + while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) { + event = sctp_skb2event(skb); + sctp_ulpevent_free(event); + } + + while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) { + event = sctp_skb2event(skb); + sctp_ulpevent_free(event); + } + +} + +/* Dispose of a ulpqueue. */ +void sctp_ulpq_free(struct sctp_ulpq *ulpq) +{ + sctp_ulpq_flush(ulpq); +} + +/* Process an incoming DATA chunk. */ +int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, + gfp_t gfp) +{ + struct sk_buff_head temp; + struct sctp_ulpevent *event; + int event_eor = 0; + + /* Create an event from the incoming chunk. */ + event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp); + if (!event) + return -ENOMEM; + + /* Do reassembly if needed. */ + event = sctp_ulpq_reasm(ulpq, event); + + /* Do ordering if needed. */ + if ((event) && (event->msg_flags & MSG_EOR)) { + /* Create a temporary list to collect chunks on. */ + skb_queue_head_init(&temp); + __skb_queue_tail(&temp, sctp_event2skb(event)); + + event = sctp_ulpq_order(ulpq, event); + } + + /* Send event to the ULP. 'event' is the sctp_ulpevent for + * very first SKB on the 'temp' list. + */ + if (event) { + event_eor = (event->msg_flags & MSG_EOR) ? 1 : 0; + sctp_ulpq_tail_event(ulpq, event); + } + + return event_eor; +} + +/* Add a new event for propagation to the ULP. */ +/* Clear the partial delivery mode for this socket. Note: This + * assumes that no association is currently in partial delivery mode. + */ +int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc) +{ + struct sctp_sock *sp = sctp_sk(sk); + + if (atomic_dec_and_test(&sp->pd_mode)) { + /* This means there are no other associations in PD, so + * we can go ahead and clear out the lobby in one shot + */ + if (!skb_queue_empty(&sp->pd_lobby)) { + struct list_head *list; + sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue); + list = (struct list_head *)&sctp_sk(sk)->pd_lobby; + INIT_LIST_HEAD(list); + return 1; + } + } else { + /* There are other associations in PD, so we only need to + * pull stuff out of the lobby that belongs to the + * associations that is exiting PD (all of its notifications + * are posted here). + */ + if (!skb_queue_empty(&sp->pd_lobby) && asoc) { + struct sk_buff *skb, *tmp; + struct sctp_ulpevent *event; + + sctp_skb_for_each(skb, &sp->pd_lobby, tmp) { + event = sctp_skb2event(skb); + if (event->asoc == asoc) { + __skb_unlink(skb, &sp->pd_lobby); + __skb_queue_tail(&sk->sk_receive_queue, + skb); + } + } + } + } + + return 0; +} + +/* Set the pd_mode on the socket and ulpq */ +static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq) +{ + struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk); + + atomic_inc(&sp->pd_mode); + ulpq->pd_mode = 1; +} + +/* Clear the pd_mode and restart any pending messages waiting for delivery. */ +static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq) +{ + ulpq->pd_mode = 0; + sctp_ulpq_reasm_drain(ulpq); + return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc); +} + +/* If the SKB of 'event' is on a list, it is the first such member + * of that list. + */ +int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event) +{ + struct sock *sk = ulpq->asoc->base.sk; + struct sk_buff_head *queue, *skb_list; + struct sk_buff *skb = sctp_event2skb(event); + int clear_pd = 0; + + skb_list = (struct sk_buff_head *) skb->prev; + + /* If the socket is just going to throw this away, do not + * even try to deliver it. + */ + if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN)) + goto out_free; + + if (!sctp_ulpevent_is_notification(event)) { + sk_mark_napi_id(sk, skb); + sk_incoming_cpu_update(sk); + } + /* Check if the user wishes to receive this event. */ + if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe)) + goto out_free; + + /* If we are in partial delivery mode, post to the lobby until + * partial delivery is cleared, unless, of course _this_ is + * the association the cause of the partial delivery. + */ + + if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) { + queue = &sk->sk_receive_queue; + } else { + if (ulpq->pd_mode) { + /* If the association is in partial delivery, we + * need to finish delivering the partially processed + * packet before passing any other data. This is + * because we don't truly support stream interleaving. + */ + if ((event->msg_flags & MSG_NOTIFICATION) || + (SCTP_DATA_NOT_FRAG == + (event->msg_flags & SCTP_DATA_FRAG_MASK))) + queue = &sctp_sk(sk)->pd_lobby; + else { + clear_pd = event->msg_flags & MSG_EOR; + queue = &sk->sk_receive_queue; + } + } else { + /* + * If fragment interleave is enabled, we + * can queue this to the receive queue instead + * of the lobby. + */ + if (sctp_sk(sk)->frag_interleave) + queue = &sk->sk_receive_queue; + else + queue = &sctp_sk(sk)->pd_lobby; + } + } + + /* If we are harvesting multiple skbs they will be + * collected on a list. + */ + if (skb_list) + sctp_skb_list_tail(skb_list, queue); + else + __skb_queue_tail(queue, skb); + + /* Did we just complete partial delivery and need to get + * rolling again? Move pending data to the receive + * queue. + */ + if (clear_pd) + sctp_ulpq_clear_pd(ulpq); + + if (queue == &sk->sk_receive_queue) + sk->sk_data_ready(sk); + return 1; + +out_free: + if (skb_list) + sctp_queue_purge_ulpevents(skb_list); + else + sctp_ulpevent_free(event); + + return 0; +} + +/* 2nd Level Abstractions */ + +/* Helper function to store chunks that need to be reassembled. */ +static void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *event) +{ + struct sk_buff *pos; + struct sctp_ulpevent *cevent; + __u32 tsn, ctsn; + + tsn = event->tsn; + + /* See if it belongs at the end. */ + pos = skb_peek_tail(&ulpq->reasm); + if (!pos) { + __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event)); + return; + } + + /* Short circuit just dropping it at the end. */ + cevent = sctp_skb2event(pos); + ctsn = cevent->tsn; + if (TSN_lt(ctsn, tsn)) { + __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event)); + return; + } + + /* Find the right place in this list. We store them by TSN. */ + skb_queue_walk(&ulpq->reasm, pos) { + cevent = sctp_skb2event(pos); + ctsn = cevent->tsn; + + if (TSN_lt(tsn, ctsn)) + break; + } + + /* Insert before pos. */ + __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event)); + +} + +/* Helper function to return an event corresponding to the reassembled + * datagram. + * This routine creates a re-assembled skb given the first and last skb's + * as stored in the reassembly queue. The skb's may be non-linear if the sctp + * payload was fragmented on the way and ip had to reassemble them. + * We add the rest of skb's to the first skb's fraglist. + */ +static struct sctp_ulpevent *sctp_make_reassembled_event(struct net *net, + struct sk_buff_head *queue, struct sk_buff *f_frag, + struct sk_buff *l_frag) +{ + struct sk_buff *pos; + struct sk_buff *new = NULL; + struct sctp_ulpevent *event; + struct sk_buff *pnext, *last; + struct sk_buff *list = skb_shinfo(f_frag)->frag_list; + + /* Store the pointer to the 2nd skb */ + if (f_frag == l_frag) + pos = NULL; + else + pos = f_frag->next; + + /* Get the last skb in the f_frag's frag_list if present. */ + for (last = list; list; last = list, list = list->next) + ; + + /* Add the list of remaining fragments to the first fragments + * frag_list. + */ + if (last) + last->next = pos; + else { + if (skb_cloned(f_frag)) { + /* This is a cloned skb, we can't just modify + * the frag_list. We need a new skb to do that. + * Instead of calling skb_unshare(), we'll do it + * ourselves since we need to delay the free. + */ + new = skb_copy(f_frag, GFP_ATOMIC); + if (!new) + return NULL; /* try again later */ + + sctp_skb_set_owner_r(new, f_frag->sk); + + skb_shinfo(new)->frag_list = pos; + } else + skb_shinfo(f_frag)->frag_list = pos; + } + + /* Remove the first fragment from the reassembly queue. */ + __skb_unlink(f_frag, queue); + + /* if we did unshare, then free the old skb and re-assign */ + if (new) { + kfree_skb(f_frag); + f_frag = new; + } + + while (pos) { + + pnext = pos->next; + + /* Update the len and data_len fields of the first fragment. */ + f_frag->len += pos->len; + f_frag->data_len += pos->len; + + /* Remove the fragment from the reassembly queue. */ + __skb_unlink(pos, queue); + + /* Break if we have reached the last fragment. */ + if (pos == l_frag) + break; + pos->next = pnext; + pos = pnext; + } + + event = sctp_skb2event(f_frag); + SCTP_INC_STATS(net, SCTP_MIB_REASMUSRMSGS); + + return event; +} + + +/* Helper function to check if an incoming chunk has filled up the last + * missing fragment in a SCTP datagram and return the corresponding event. + */ +static struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq) +{ + struct sk_buff *pos; + struct sctp_ulpevent *cevent; + struct sk_buff *first_frag = NULL; + __u32 ctsn, next_tsn; + struct sctp_ulpevent *retval = NULL; + struct sk_buff *pd_first = NULL; + struct sk_buff *pd_last = NULL; + size_t pd_len = 0; + struct sctp_association *asoc; + u32 pd_point; + + /* Initialized to 0 just to avoid compiler warning message. Will + * never be used with this value. It is referenced only after it + * is set when we find the first fragment of a message. + */ + next_tsn = 0; + + /* The chunks are held in the reasm queue sorted by TSN. + * Walk through the queue sequentially and look for a sequence of + * fragmented chunks that complete a datagram. + * 'first_frag' and next_tsn are reset when we find a chunk which + * is the first fragment of a datagram. Once these 2 fields are set + * we expect to find the remaining middle fragments and the last + * fragment in order. If not, first_frag is reset to NULL and we + * start the next pass when we find another first fragment. + * + * There is a potential to do partial delivery if user sets + * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here + * to see if can do PD. + */ + skb_queue_walk(&ulpq->reasm, pos) { + cevent = sctp_skb2event(pos); + ctsn = cevent->tsn; + + switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { + case SCTP_DATA_FIRST_FRAG: + /* If this "FIRST_FRAG" is the first + * element in the queue, then count it towards + * possible PD. + */ + if (pos == ulpq->reasm.next) { + pd_first = pos; + pd_last = pos; + pd_len = pos->len; + } else { + pd_first = NULL; + pd_last = NULL; + pd_len = 0; + } + + first_frag = pos; + next_tsn = ctsn + 1; + break; + + case SCTP_DATA_MIDDLE_FRAG: + if ((first_frag) && (ctsn == next_tsn)) { + next_tsn++; + if (pd_first) { + pd_last = pos; + pd_len += pos->len; + } + } else + first_frag = NULL; + break; + + case SCTP_DATA_LAST_FRAG: + if (first_frag && (ctsn == next_tsn)) + goto found; + else + first_frag = NULL; + break; + } + } + + asoc = ulpq->asoc; + if (pd_first) { + /* Make sure we can enter partial deliver. + * We can trigger partial delivery only if framgent + * interleave is set, or the socket is not already + * in partial delivery. + */ + if (!sctp_sk(asoc->base.sk)->frag_interleave && + atomic_read(&sctp_sk(asoc->base.sk)->pd_mode)) + goto done; + + cevent = sctp_skb2event(pd_first); + pd_point = sctp_sk(asoc->base.sk)->pd_point; + if (pd_point && pd_point <= pd_len) { + retval = sctp_make_reassembled_event(sock_net(asoc->base.sk), + &ulpq->reasm, + pd_first, + pd_last); + if (retval) + sctp_ulpq_set_pd(ulpq); + } + } +done: + return retval; +found: + retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk), + &ulpq->reasm, first_frag, pos); + if (retval) + retval->msg_flags |= MSG_EOR; + goto done; +} + +/* Retrieve the next set of fragments of a partial message. */ +static struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq) +{ + struct sk_buff *pos, *last_frag, *first_frag; + struct sctp_ulpevent *cevent; + __u32 ctsn, next_tsn; + int is_last; + struct sctp_ulpevent *retval; + + /* The chunks are held in the reasm queue sorted by TSN. + * Walk through the queue sequentially and look for the first + * sequence of fragmented chunks. + */ + + if (skb_queue_empty(&ulpq->reasm)) + return NULL; + + last_frag = first_frag = NULL; + retval = NULL; + next_tsn = 0; + is_last = 0; + + skb_queue_walk(&ulpq->reasm, pos) { + cevent = sctp_skb2event(pos); + ctsn = cevent->tsn; + + switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { + case SCTP_DATA_FIRST_FRAG: + if (!first_frag) + return NULL; + goto done; + case SCTP_DATA_MIDDLE_FRAG: + if (!first_frag) { + first_frag = pos; + next_tsn = ctsn + 1; + last_frag = pos; + } else if (next_tsn == ctsn) { + next_tsn++; + last_frag = pos; + } else + goto done; + break; + case SCTP_DATA_LAST_FRAG: + if (!first_frag) + first_frag = pos; + else if (ctsn != next_tsn) + goto done; + last_frag = pos; + is_last = 1; + goto done; + default: + return NULL; + } + } + + /* We have the reassembled event. There is no need to look + * further. + */ +done: + retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk), + &ulpq->reasm, first_frag, last_frag); + if (retval && is_last) + retval->msg_flags |= MSG_EOR; + + return retval; +} + + +/* Helper function to reassemble chunks. Hold chunks on the reasm queue that + * need reassembling. + */ +static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *event) +{ + struct sctp_ulpevent *retval = NULL; + + /* Check if this is part of a fragmented message. */ + if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) { + event->msg_flags |= MSG_EOR; + return event; + } + + sctp_ulpq_store_reasm(ulpq, event); + if (!ulpq->pd_mode) + retval = sctp_ulpq_retrieve_reassembled(ulpq); + else { + __u32 ctsn, ctsnap; + + /* Do not even bother unless this is the next tsn to + * be delivered. + */ + ctsn = event->tsn; + ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map); + if (TSN_lte(ctsn, ctsnap)) + retval = sctp_ulpq_retrieve_partial(ulpq); + } + + return retval; +} + +/* Retrieve the first part (sequential fragments) for partial delivery. */ +static struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq) +{ + struct sk_buff *pos, *last_frag, *first_frag; + struct sctp_ulpevent *cevent; + __u32 ctsn, next_tsn; + struct sctp_ulpevent *retval; + + /* The chunks are held in the reasm queue sorted by TSN. + * Walk through the queue sequentially and look for a sequence of + * fragmented chunks that start a datagram. + */ + + if (skb_queue_empty(&ulpq->reasm)) + return NULL; + + last_frag = first_frag = NULL; + retval = NULL; + next_tsn = 0; + + skb_queue_walk(&ulpq->reasm, pos) { + cevent = sctp_skb2event(pos); + ctsn = cevent->tsn; + + switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { + case SCTP_DATA_FIRST_FRAG: + if (!first_frag) { + first_frag = pos; + next_tsn = ctsn + 1; + last_frag = pos; + } else + goto done; + break; + + case SCTP_DATA_MIDDLE_FRAG: + if (!first_frag) + return NULL; + if (ctsn == next_tsn) { + next_tsn++; + last_frag = pos; + } else + goto done; + break; + + case SCTP_DATA_LAST_FRAG: + if (!first_frag) + return NULL; + else + goto done; + break; + + default: + return NULL; + } + } + + /* We have the reassembled event. There is no need to look + * further. + */ +done: + retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk), + &ulpq->reasm, first_frag, last_frag); + return retval; +} + +/* + * Flush out stale fragments from the reassembly queue when processing + * a Forward TSN. + * + * RFC 3758, Section 3.6 + * + * After receiving and processing a FORWARD TSN, the data receiver MUST + * take cautions in updating its re-assembly queue. The receiver MUST + * remove any partially reassembled message, which is still missing one + * or more TSNs earlier than or equal to the new cumulative TSN point. + * In the event that the receiver has invoked the partial delivery API, + * a notification SHOULD also be generated to inform the upper layer API + * that the message being partially delivered will NOT be completed. + */ +void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn) +{ + struct sk_buff *pos, *tmp; + struct sctp_ulpevent *event; + __u32 tsn; + + if (skb_queue_empty(&ulpq->reasm)) + return; + + skb_queue_walk_safe(&ulpq->reasm, pos, tmp) { + event = sctp_skb2event(pos); + tsn = event->tsn; + + /* Since the entire message must be abandoned by the + * sender (item A3 in Section 3.5, RFC 3758), we can + * free all fragments on the list that are less then + * or equal to ctsn_point + */ + if (TSN_lte(tsn, fwd_tsn)) { + __skb_unlink(pos, &ulpq->reasm); + sctp_ulpevent_free(event); + } else + break; + } +} + +/* + * Drain the reassembly queue. If we just cleared parted delivery, it + * is possible that the reassembly queue will contain already reassembled + * messages. Retrieve any such messages and give them to the user. + */ +static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq) +{ + struct sctp_ulpevent *event = NULL; + struct sk_buff_head temp; + + if (skb_queue_empty(&ulpq->reasm)) + return; + + while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) { + /* Do ordering if needed. */ + if ((event) && (event->msg_flags & MSG_EOR)) { + skb_queue_head_init(&temp); + __skb_queue_tail(&temp, sctp_event2skb(event)); + + event = sctp_ulpq_order(ulpq, event); + } + + /* Send event to the ULP. 'event' is the + * sctp_ulpevent for very first SKB on the temp' list. + */ + if (event) + sctp_ulpq_tail_event(ulpq, event); + } +} + + +/* Helper function to gather skbs that have possibly become + * ordered by an an incoming chunk. + */ +static void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *event) +{ + struct sk_buff_head *event_list; + struct sk_buff *pos, *tmp; + struct sctp_ulpevent *cevent; + struct sctp_stream *in; + __u16 sid, csid, cssn; + + sid = event->stream; + in = &ulpq->asoc->ssnmap->in; + + event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev; + + /* We are holding the chunks by stream, by SSN. */ + sctp_skb_for_each(pos, &ulpq->lobby, tmp) { + cevent = (struct sctp_ulpevent *) pos->cb; + csid = cevent->stream; + cssn = cevent->ssn; + + /* Have we gone too far? */ + if (csid > sid) + break; + + /* Have we not gone far enough? */ + if (csid < sid) + continue; + + if (cssn != sctp_ssn_peek(in, sid)) + break; + + /* Found it, so mark in the ssnmap. */ + sctp_ssn_next(in, sid); + + __skb_unlink(pos, &ulpq->lobby); + + /* Attach all gathered skbs to the event. */ + __skb_queue_tail(event_list, pos); + } +} + +/* Helper function to store chunks needing ordering. */ +static void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *event) +{ + struct sk_buff *pos; + struct sctp_ulpevent *cevent; + __u16 sid, csid; + __u16 ssn, cssn; + + pos = skb_peek_tail(&ulpq->lobby); + if (!pos) { + __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); + return; + } + + sid = event->stream; + ssn = event->ssn; + + cevent = (struct sctp_ulpevent *) pos->cb; + csid = cevent->stream; + cssn = cevent->ssn; + if (sid > csid) { + __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); + return; + } + + if ((sid == csid) && SSN_lt(cssn, ssn)) { + __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); + return; + } + + /* Find the right place in this list. We store them by + * stream ID and then by SSN. + */ + skb_queue_walk(&ulpq->lobby, pos) { + cevent = (struct sctp_ulpevent *) pos->cb; + csid = cevent->stream; + cssn = cevent->ssn; + + if (csid > sid) + break; + if (csid == sid && SSN_lt(ssn, cssn)) + break; + } + + + /* Insert before pos. */ + __skb_queue_before(&ulpq->lobby, pos, sctp_event2skb(event)); +} + +static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq, + struct sctp_ulpevent *event) +{ + __u16 sid, ssn; + struct sctp_stream *in; + + /* Check if this message needs ordering. */ + if (SCTP_DATA_UNORDERED & event->msg_flags) + return event; + + /* Note: The stream ID must be verified before this routine. */ + sid = event->stream; + ssn = event->ssn; + in = &ulpq->asoc->ssnmap->in; + + /* Is this the expected SSN for this stream ID? */ + if (ssn != sctp_ssn_peek(in, sid)) { + /* We've received something out of order, so find where it + * needs to be placed. We order by stream and then by SSN. + */ + sctp_ulpq_store_ordered(ulpq, event); + return NULL; + } + + /* Mark that the next chunk has been found. */ + sctp_ssn_next(in, sid); + + /* Go find any other chunks that were waiting for + * ordering. + */ + sctp_ulpq_retrieve_ordered(ulpq, event); + + return event; +} + +/* Helper function to gather skbs that have possibly become + * ordered by forward tsn skipping their dependencies. + */ +static void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid) +{ + struct sk_buff *pos, *tmp; + struct sctp_ulpevent *cevent; + struct sctp_ulpevent *event; + struct sctp_stream *in; + struct sk_buff_head temp; + struct sk_buff_head *lobby = &ulpq->lobby; + __u16 csid, cssn; + + in = &ulpq->asoc->ssnmap->in; + + /* We are holding the chunks by stream, by SSN. */ + skb_queue_head_init(&temp); + event = NULL; + sctp_skb_for_each(pos, lobby, tmp) { + cevent = (struct sctp_ulpevent *) pos->cb; + csid = cevent->stream; + cssn = cevent->ssn; + + /* Have we gone too far? */ + if (csid > sid) + break; + + /* Have we not gone far enough? */ + if (csid < sid) + continue; + + /* see if this ssn has been marked by skipping */ + if (!SSN_lt(cssn, sctp_ssn_peek(in, csid))) + break; + + __skb_unlink(pos, lobby); + if (!event) + /* Create a temporary list to collect chunks on. */ + event = sctp_skb2event(pos); + + /* Attach all gathered skbs to the event. */ + __skb_queue_tail(&temp, pos); + } + + /* If we didn't reap any data, see if the next expected SSN + * is next on the queue and if so, use that. + */ + if (event == NULL && pos != (struct sk_buff *)lobby) { + cevent = (struct sctp_ulpevent *) pos->cb; + csid = cevent->stream; + cssn = cevent->ssn; + + if (csid == sid && cssn == sctp_ssn_peek(in, csid)) { + sctp_ssn_next(in, csid); + __skb_unlink(pos, lobby); + __skb_queue_tail(&temp, pos); + event = sctp_skb2event(pos); + } + } + + /* Send event to the ULP. 'event' is the sctp_ulpevent for + * very first SKB on the 'temp' list. + */ + if (event) { + /* see if we have more ordered that we can deliver */ + sctp_ulpq_retrieve_ordered(ulpq, event); + sctp_ulpq_tail_event(ulpq, event); + } +} + +/* Skip over an SSN. This is used during the processing of + * Forwared TSN chunk to skip over the abandoned ordered data + */ +void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn) +{ + struct sctp_stream *in; + + /* Note: The stream ID must be verified before this routine. */ + in = &ulpq->asoc->ssnmap->in; + + /* Is this an old SSN? If so ignore. */ + if (SSN_lt(ssn, sctp_ssn_peek(in, sid))) + return; + + /* Mark that we are no longer expecting this SSN or lower. */ + sctp_ssn_skip(in, sid, ssn); + + /* Go find any other chunks that were waiting for + * ordering and deliver them if needed. + */ + sctp_ulpq_reap_ordered(ulpq, sid); +} + +static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq, + struct sk_buff_head *list, __u16 needed) +{ + __u16 freed = 0; + __u32 tsn, last_tsn; + struct sk_buff *skb, *flist, *last; + struct sctp_ulpevent *event; + struct sctp_tsnmap *tsnmap; + + tsnmap = &ulpq->asoc->peer.tsn_map; + + while ((skb = skb_peek_tail(list)) != NULL) { + event = sctp_skb2event(skb); + tsn = event->tsn; + + /* Don't renege below the Cumulative TSN ACK Point. */ + if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap))) + break; + + /* Events in ordering queue may have multiple fragments + * corresponding to additional TSNs. Sum the total + * freed space; find the last TSN. + */ + freed += skb_headlen(skb); + flist = skb_shinfo(skb)->frag_list; + for (last = flist; flist; flist = flist->next) { + last = flist; + freed += skb_headlen(last); + } + if (last) + last_tsn = sctp_skb2event(last)->tsn; + else + last_tsn = tsn; + + /* Unlink the event, then renege all applicable TSNs. */ + __skb_unlink(skb, list); + sctp_ulpevent_free(event); + while (TSN_lte(tsn, last_tsn)) { + sctp_tsnmap_renege(tsnmap, tsn); + tsn++; + } + if (freed >= needed) + return freed; + } + + return freed; +} + +/* Renege 'needed' bytes from the ordering queue. */ +static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed) +{ + return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed); +} + +/* Renege 'needed' bytes from the reassembly queue. */ +static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed) +{ + return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed); +} + +/* Partial deliver the first message as there is pressure on rwnd. */ +void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq, + gfp_t gfp) +{ + struct sctp_ulpevent *event; + struct sctp_association *asoc; + struct sctp_sock *sp; + __u32 ctsn; + struct sk_buff *skb; + + asoc = ulpq->asoc; + sp = sctp_sk(asoc->base.sk); + + /* If the association is already in Partial Delivery mode + * we have nothing to do. + */ + if (ulpq->pd_mode) + return; + + /* Data must be at or below the Cumulative TSN ACK Point to + * start partial delivery. + */ + skb = skb_peek(&asoc->ulpq.reasm); + if (skb != NULL) { + ctsn = sctp_skb2event(skb)->tsn; + if (!TSN_lte(ctsn, sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map))) + return; + } + + /* If the user enabled fragment interleave socket option, + * multiple associations can enter partial delivery. + * Otherwise, we can only enter partial delivery if the + * socket is not in partial deliver mode. + */ + if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) { + /* Is partial delivery possible? */ + event = sctp_ulpq_retrieve_first(ulpq); + /* Send event to the ULP. */ + if (event) { + sctp_ulpq_tail_event(ulpq, event); + sctp_ulpq_set_pd(ulpq); + return; + } + } +} + +/* Renege some packets to make room for an incoming chunk. */ +void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, + gfp_t gfp) +{ + struct sctp_association *asoc; + __u16 needed, freed; + + asoc = ulpq->asoc; + + if (chunk) { + needed = ntohs(chunk->chunk_hdr->length); + needed -= sizeof(sctp_data_chunk_t); + } else + needed = SCTP_DEFAULT_MAXWINDOW; + + freed = 0; + + if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) { + freed = sctp_ulpq_renege_order(ulpq, needed); + if (freed < needed) { + freed += sctp_ulpq_renege_frags(ulpq, needed - freed); + } + } + /* If able to free enough room, accept this chunk. */ + if (chunk && (freed >= needed)) { + int retval; + retval = sctp_ulpq_tail_data(ulpq, chunk, gfp); + /* + * Enter partial delivery if chunk has not been + * delivered; otherwise, drain the reassembly queue. + */ + if (retval <= 0) + sctp_ulpq_partial_delivery(ulpq, gfp); + else if (retval == 1) + sctp_ulpq_reasm_drain(ulpq); + } + + sk_mem_reclaim(asoc->base.sk); +} + + + +/* Notify the application if an association is aborted and in + * partial delivery mode. Send up any pending received messages. + */ +void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp) +{ + struct sctp_ulpevent *ev = NULL; + struct sock *sk; + + if (!ulpq->pd_mode) + return; + + sk = ulpq->asoc->base.sk; + if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT, + &sctp_sk(sk)->subscribe)) + ev = sctp_ulpevent_make_pdapi(ulpq->asoc, + SCTP_PARTIAL_DELIVERY_ABORTED, + gfp); + if (ev) + __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev)); + + /* If there is data waiting, send it up the socket now. */ + if (sctp_ulpq_clear_pd(ulpq) || ev) + sk->sk_data_ready(sk); +} |