/* SCTP kernel reference 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). * * The SCTP reference 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. * * The SCTP reference 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, write to * the Free Software Foundation, 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers * * Or submit a bug report through the following website: * http://www.sf.net/projects/lksctp * * Written or modified by: * Jon Grimm * La Monte H.P. Yarroll * Sridhar Samudrala * * Any bugs reported given to us we will try to fix... any fixes shared will * be incorporated into the next SCTP release. */ #include #include #include #include #include #include /* 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 *); /* 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; ulpq->malloced = 0; return ulpq; } /* Flush the reassembly and ordering queues. */ static 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); if (ulpq->malloced) kfree(ulpq); } /* Process an incoming DATA chunk. */ int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, unsigned int __nocast gfp) { struct sk_buff_head temp; sctp_data_chunk_t *hdr; struct sctp_ulpevent *event; hdr = (sctp_data_chunk_t *) chunk->chunk_hdr; /* 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. */ if (event) sctp_ulpq_tail_event(ulpq, event); return 0; } /* 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_sock *sp = sctp_sk(sk); sp->pd_mode = 0; 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; } return 0; } /* 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; return sctp_clear_pd(ulpq->asoc->base.sk); } 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; int clear_pd = 0; /* 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; /* 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 (!sctp_sk(sk)->pd_mode) { queue = &sk->sk_receive_queue; } else if (ulpq->pd_mode) { if (event->msg_flags & MSG_NOTIFICATION) queue = &sctp_sk(sk)->pd_lobby; else { clear_pd = event->msg_flags & MSG_EOR; 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 (sctp_event2skb(event)->list) sctp_skb_list_tail(sctp_event2skb(event)->list, queue); else __skb_queue_tail(queue, sctp_event2skb(event)); /* 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, 0); return 1; out_free: if (sctp_event2skb(event)->list) sctp_queue_purge_ulpevents(sctp_event2skb(event)->list); else sctp_ulpevent_free(event); return 0; } /* 2nd Level Abstractions */ /* Helper function to store chunks that need to be reassembled. */ static inline 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_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->reasm); } /* 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 sk_buff *f_frag, struct sk_buff *l_frag) { struct sk_buff *pos; 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 skb_shinfo(f_frag)->frag_list = pos; /* Remove the first fragment from the reassembly queue. */ __skb_unlink(f_frag, f_frag->list); 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, pos->list); /* 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(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 inline 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; /* 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. */ 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: first_frag = pos; next_tsn = ctsn + 1; break; case SCTP_DATA_MIDDLE_FRAG: if ((first_frag) && (ctsn == next_tsn)) next_tsn++; else first_frag = NULL; break; case SCTP_DATA_LAST_FRAG: if (first_frag && (ctsn == next_tsn)) goto found; else first_frag = NULL; break; }; } done: return retval; found: retval = sctp_make_reassembled_event(first_frag, pos); if (retval) retval->msg_flags |= MSG_EOR; goto done; } /* Retrieve the next set of fragments of a partial message. */ static inline 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_MIDDLE_FRAG: if (!first_frag) { first_frag = pos; next_tsn = ctsn + 1; last_frag = pos; } else if (next_tsn == ctsn) next_tsn++; 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(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 inline 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; default: return NULL; }; } /* We have the reassembled event. There is no need to look * further. */ done: retval = sctp_make_reassembled_event(first_frag, last_frag); return retval; } /* Helper function to gather skbs that have possibly become * ordered by an an incoming chunk. */ static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event) { struct sk_buff *pos, *tmp; struct sctp_ulpevent *cevent; struct sctp_stream *in; __u16 sid, csid; __u16 ssn, cssn; sid = event->stream; ssn = event->ssn; in = &ulpq->asoc->ssnmap->in; /* 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, pos->list); /* Attach all gathered skbs to the event. */ __skb_queue_tail(sctp_event2skb(event)->list, pos); } } /* Helper function to store chunks needing ordering. */ static inline 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_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->lobby); } 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 inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq) { struct sk_buff *pos, *tmp; struct sctp_ulpevent *cevent; struct sctp_ulpevent *event = NULL; struct sctp_stream *in; struct sk_buff_head temp; __u16 csid, cssn; in = &ulpq->asoc->ssnmap->in; /* 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; if (cssn != sctp_ssn_peek(in, csid)) break; /* Found it, so mark in the ssnmap. */ sctp_ssn_next(in, csid); __skb_unlink(pos, pos->list); if (!event) { /* Create a temporary list to collect chunks on. */ event = sctp_skb2event(pos); skb_queue_head_init(&temp); __skb_queue_tail(&temp, sctp_event2skb(event)); } else { /* Attach all gathered skbs to the event. */ __skb_queue_tail(sctp_event2skb(event)->list, pos); } } /* Send event to the ULP. */ if (event) sctp_ulpq_tail_event(ulpq, event); } /* Skip over an SSN. */ 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); return; } /* Renege 'needed' bytes from the ordering queue. */ static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed) { __u16 freed = 0; __u32 tsn; struct sk_buff *skb; struct sctp_ulpevent *event; struct sctp_tsnmap *tsnmap; tsnmap = &ulpq->asoc->peer.tsn_map; while ((skb = __skb_dequeue_tail(&ulpq->lobby)) != NULL) { freed += skb_headlen(skb); event = sctp_skb2event(skb); tsn = event->tsn; sctp_ulpevent_free(event); sctp_tsnmap_renege(tsnmap, tsn); if (freed >= needed) return freed; } return freed; } /* Renege 'needed' bytes from the reassembly queue. */ static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed) { __u16 freed = 0; __u32 tsn; struct sk_buff *skb; struct sctp_ulpevent *event; struct sctp_tsnmap *tsnmap; tsnmap = &ulpq->asoc->peer.tsn_map; /* Walk backwards through the list, reneges the newest tsns. */ while ((skb = __skb_dequeue_tail(&ulpq->reasm)) != NULL) { freed += skb_headlen(skb); event = sctp_skb2event(skb); tsn = event->tsn; sctp_ulpevent_free(event); sctp_tsnmap_renege(tsnmap, tsn); if (freed >= needed) return freed; } return freed; } /* Partial deliver the first message as there is pressure on rwnd. */ void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, unsigned int __nocast gfp) { struct sctp_ulpevent *event; struct sctp_association *asoc; asoc = ulpq->asoc; /* Are we already in partial delivery mode? */ if (!sctp_sk(asoc->base.sk)->pd_mode) { /* Is partial delivery possible? */ event = sctp_ulpq_retrieve_first(ulpq); /* Send event to the ULP. */ if (event) { sctp_ulpq_tail_event(ulpq, event); sctp_sk(asoc->base.sk)->pd_mode = 1; ulpq->pd_mode = 1; return; } } } /* Renege some packets to make room for an incoming chunk. */ void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, unsigned int __nocast 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)) { __u32 tsn; tsn = ntohl(chunk->subh.data_hdr->tsn); sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn); sctp_ulpq_tail_data(ulpq, chunk, gfp); sctp_ulpq_partial_delivery(ulpq, chunk, gfp); } return; } /* 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, unsigned int __nocast 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, 0); }