1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
6 * This file is part of the SCTP kernel implementation
8 * These functions handle output processing.
10 * This SCTP implementation is free software;
11 * you can redistribute it and/or modify it under the terms of
12 * the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
16 * This SCTP implementation is distributed in the hope that it
17 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
18 * ************************
19 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
20 * See the GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with GNU CC; see the file COPYING. If not, write to
24 * the Free Software Foundation, 59 Temple Place - Suite 330,
25 * Boston, MA 02111-1307, USA.
27 * Please send any bug reports or fixes you make to the
29 * lksctp developers <lksctp-developers@lists.sourceforge.net>
31 * Or submit a bug report through the following website:
32 * http://www.sf.net/projects/lksctp
34 * Written or modified by:
35 * La Monte H.P. Yarroll <piggy@acm.org>
36 * Karl Knutson <karl@athena.chicago.il.us>
37 * Jon Grimm <jgrimm@austin.ibm.com>
38 * Sridhar Samudrala <sri@us.ibm.com>
40 * Any bugs reported given to us we will try to fix... any fixes shared will
41 * be incorporated into the next SCTP release.
44 #include <linux/types.h>
45 #include <linux/kernel.h>
46 #include <linux/wait.h>
47 #include <linux/time.h>
49 #include <linux/ipv6.h>
50 #include <linux/init.h>
51 #include <net/inet_ecn.h>
54 #include <net/net_namespace.h>
56 #include <linux/socket.h> /* for sa_family_t */
59 #include <net/sctp/sctp.h>
60 #include <net/sctp/sm.h>
61 #include <net/sctp/checksum.h>
63 /* Forward declarations for private helpers. */
64 static sctp_xmit_t
sctp_packet_can_append_data(struct sctp_packet
*packet
,
65 struct sctp_chunk
*chunk
);
66 static void sctp_packet_append_data(struct sctp_packet
*packet
,
67 struct sctp_chunk
*chunk
);
68 static sctp_xmit_t
sctp_packet_will_fit(struct sctp_packet
*packet
,
69 struct sctp_chunk
*chunk
,
73 * This appears to be a followup set of initializations.
75 struct sctp_packet
*sctp_packet_config(struct sctp_packet
*packet
,
76 __u32 vtag
, int ecn_capable
)
78 struct sctp_chunk
*chunk
= NULL
;
80 SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__
,
84 packet
->has_cookie_echo
= 0;
91 if (ecn_capable
&& sctp_packet_empty(packet
)) {
92 chunk
= sctp_get_ecne_prepend(packet
->transport
->asoc
);
94 /* If there a is a prepend chunk stick it on the list before
95 * any other chunks get appended.
98 sctp_packet_append_chunk(packet
, chunk
);
104 /* Initialize the packet structure. */
105 struct sctp_packet
*sctp_packet_init(struct sctp_packet
*packet
,
106 struct sctp_transport
*transport
,
107 __u16 sport
, __u16 dport
)
109 struct sctp_association
*asoc
= transport
->asoc
;
112 SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__
,
115 packet
->transport
= transport
;
116 packet
->source_port
= sport
;
117 packet
->destination_port
= dport
;
118 INIT_LIST_HEAD(&packet
->chunk_list
);
120 struct sctp_sock
*sp
= sctp_sk(asoc
->base
.sk
);
121 overhead
= sp
->pf
->af
->net_header_len
;
123 overhead
= sizeof(struct ipv6hdr
);
125 overhead
+= sizeof(struct sctphdr
);
126 packet
->overhead
= overhead
;
127 packet
->size
= overhead
;
129 packet
->has_cookie_echo
= 0;
130 packet
->has_sack
= 0;
131 packet
->has_auth
= 0;
132 packet
->has_data
= 0;
133 packet
->ipfragok
= 0;
134 packet
->malloced
= 0;
139 static void sctp_packet_reset(struct sctp_packet
*packet
)
141 packet
->size
= packet
->overhead
;
142 packet
->has_cookie_echo
= 0;
143 packet
->has_sack
= 0;
144 packet
->has_data
= 0;
145 packet
->has_auth
= 0;
146 packet
->ipfragok
= 0;
151 void sctp_packet_free(struct sctp_packet
*packet
)
153 struct sctp_chunk
*chunk
, *tmp
;
155 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__
, packet
);
157 list_for_each_entry_safe(chunk
, tmp
, &packet
->chunk_list
, list
) {
158 list_del_init(&chunk
->list
);
159 sctp_chunk_free(chunk
);
162 if (packet
->malloced
)
166 /* This routine tries to append the chunk to the offered packet. If adding
167 * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk
168 * is not present in the packet, it transmits the input packet.
169 * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long
170 * as it can fit in the packet, but any more data that does not fit in this
171 * packet can be sent only after receiving the COOKIE_ACK.
173 sctp_xmit_t
sctp_packet_transmit_chunk(struct sctp_packet
*packet
,
174 struct sctp_chunk
*chunk
,
180 SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__
,
183 switch ((retval
= (sctp_packet_append_chunk(packet
, chunk
)))) {
184 case SCTP_XMIT_PMTU_FULL
:
185 if (!packet
->has_cookie_echo
) {
186 error
= sctp_packet_transmit(packet
);
188 chunk
->skb
->sk
->sk_err
= -error
;
190 /* If we have an empty packet, then we can NOT ever
194 retval
= sctp_packet_append_chunk(packet
,
199 case SCTP_XMIT_RWND_FULL
:
201 case SCTP_XMIT_NAGLE_DELAY
:
208 /* Try to bundle an auth chunk into the packet. */
209 static sctp_xmit_t
sctp_packet_bundle_auth(struct sctp_packet
*pkt
,
210 struct sctp_chunk
*chunk
)
212 struct sctp_association
*asoc
= pkt
->transport
->asoc
;
213 struct sctp_chunk
*auth
;
214 sctp_xmit_t retval
= SCTP_XMIT_OK
;
216 /* if we don't have an association, we can't do authentication */
220 /* See if this is an auth chunk we are bundling or if
221 * auth is already bundled.
223 if (chunk
->chunk_hdr
->type
== SCTP_CID_AUTH
|| pkt
->has_auth
)
226 /* if the peer did not request this chunk to be authenticated,
232 auth
= sctp_make_auth(asoc
);
236 retval
= sctp_packet_append_chunk(pkt
, auth
);
241 /* Try to bundle a SACK with the packet. */
242 static sctp_xmit_t
sctp_packet_bundle_sack(struct sctp_packet
*pkt
,
243 struct sctp_chunk
*chunk
)
245 sctp_xmit_t retval
= SCTP_XMIT_OK
;
247 /* If sending DATA and haven't aleady bundled a SACK, try to
248 * bundle one in to the packet.
250 if (sctp_chunk_is_data(chunk
) && !pkt
->has_sack
&&
251 !pkt
->has_cookie_echo
) {
252 struct sctp_association
*asoc
;
253 struct timer_list
*timer
;
254 asoc
= pkt
->transport
->asoc
;
255 timer
= &asoc
->timers
[SCTP_EVENT_TIMEOUT_SACK
];
257 /* If the SACK timer is running, we have a pending SACK */
258 if (timer_pending(timer
)) {
259 struct sctp_chunk
*sack
;
260 asoc
->a_rwnd
= asoc
->rwnd
;
261 sack
= sctp_make_sack(asoc
);
263 retval
= sctp_packet_append_chunk(pkt
, sack
);
264 asoc
->peer
.sack_needed
= 0;
265 if (del_timer(timer
))
266 sctp_association_put(asoc
);
273 /* Append a chunk to the offered packet reporting back any inability to do
276 sctp_xmit_t
sctp_packet_append_chunk(struct sctp_packet
*packet
,
277 struct sctp_chunk
*chunk
)
279 sctp_xmit_t retval
= SCTP_XMIT_OK
;
280 __u16 chunk_len
= WORD_ROUND(ntohs(chunk
->chunk_hdr
->length
));
282 SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__
, packet
,
285 /* Data chunks are special. Before seeing what else we can
286 * bundle into this packet, check to see if we are allowed to
289 if (sctp_chunk_is_data(chunk
)) {
290 retval
= sctp_packet_can_append_data(packet
, chunk
);
291 if (retval
!= SCTP_XMIT_OK
)
295 /* Try to bundle AUTH chunk */
296 retval
= sctp_packet_bundle_auth(packet
, chunk
);
297 if (retval
!= SCTP_XMIT_OK
)
300 /* Try to bundle SACK chunk */
301 retval
= sctp_packet_bundle_sack(packet
, chunk
);
302 if (retval
!= SCTP_XMIT_OK
)
305 /* Check to see if this chunk will fit into the packet */
306 retval
= sctp_packet_will_fit(packet
, chunk
, chunk_len
);
307 if (retval
!= SCTP_XMIT_OK
)
310 /* We believe that this chunk is OK to add to the packet */
311 switch (chunk
->chunk_hdr
->type
) {
313 /* Account for the data being in the packet */
314 sctp_packet_append_data(packet
, chunk
);
315 /* Disallow SACK bundling after DATA. */
316 packet
->has_sack
= 1;
317 /* Disallow AUTH bundling after DATA */
318 packet
->has_auth
= 1;
319 /* Let it be knows that packet has DATA in it */
320 packet
->has_data
= 1;
321 /* timestamp the chunk for rtx purposes */
322 chunk
->sent_at
= jiffies
;
324 case SCTP_CID_COOKIE_ECHO
:
325 packet
->has_cookie_echo
= 1;
329 packet
->has_sack
= 1;
333 packet
->has_auth
= 1;
334 packet
->auth
= chunk
;
338 /* It is OK to send this chunk. */
339 list_add_tail(&chunk
->list
, &packet
->chunk_list
);
340 packet
->size
+= chunk_len
;
341 chunk
->transport
= packet
->transport
;
346 /* All packets are sent to the network through this function from
349 * The return value is a normal kernel error return value.
351 int sctp_packet_transmit(struct sctp_packet
*packet
)
353 struct sctp_transport
*tp
= packet
->transport
;
354 struct sctp_association
*asoc
= tp
->asoc
;
356 struct sk_buff
*nskb
;
357 struct sctp_chunk
*chunk
, *tmp
;
360 int padding
; /* How much padding do we need? */
362 struct dst_entry
*dst
= tp
->dst
;
363 unsigned char *auth
= NULL
; /* pointer to auth in skb data */
364 __u32 cksum_buf_len
= sizeof(struct sctphdr
);
366 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__
, packet
);
368 /* Do NOT generate a chunkless packet. */
369 if (list_empty(&packet
->chunk_list
))
372 /* Set up convenience variables... */
373 chunk
= list_entry(packet
->chunk_list
.next
, struct sctp_chunk
, list
);
376 /* Allocate the new skb. */
377 nskb
= alloc_skb(packet
->size
+ LL_MAX_HEADER
, GFP_ATOMIC
);
381 /* Make sure the outbound skb has enough header room reserved. */
382 skb_reserve(nskb
, packet
->overhead
+ LL_MAX_HEADER
);
384 /* Set the owning socket so that we know where to get the
385 * destination IP address.
387 skb_set_owner_w(nskb
, sk
);
389 /* The 'obsolete' field of dst is set to 2 when a dst is freed. */
390 if (!dst
|| (dst
->obsolete
> 1)) {
392 sctp_transport_route(tp
, NULL
, sctp_sk(sk
));
393 if (asoc
&& (asoc
->param_flags
& SPP_PMTUD_ENABLE
)) {
394 sctp_assoc_sync_pmtu(asoc
);
397 dst
= dst_clone(tp
->dst
);
398 skb_dst_set(nskb
, dst
);
402 /* Build the SCTP header. */
403 sh
= (struct sctphdr
*)skb_push(nskb
, sizeof(struct sctphdr
));
404 skb_reset_transport_header(nskb
);
405 sh
->source
= htons(packet
->source_port
);
406 sh
->dest
= htons(packet
->destination_port
);
408 /* From 6.8 Adler-32 Checksum Calculation:
409 * After the packet is constructed (containing the SCTP common
410 * header and one or more control or DATA chunks), the
413 * 1) Fill in the proper Verification Tag in the SCTP common
414 * header and initialize the checksum field to 0's.
416 sh
->vtag
= htonl(packet
->vtag
);
422 * An endpoint bundles chunks by simply including multiple
423 * chunks in one outbound SCTP packet. ...
427 * 3.2 Chunk Field Descriptions
429 * The total length of a chunk (including Type, Length and
430 * Value fields) MUST be a multiple of 4 bytes. If the length
431 * of the chunk is not a multiple of 4 bytes, the sender MUST
432 * pad the chunk with all zero bytes and this padding is not
433 * included in the chunk length field. The sender should
434 * never pad with more than 3 bytes.
436 * [This whole comment explains WORD_ROUND() below.]
438 SCTP_DEBUG_PRINTK("***sctp_transmit_packet***\n");
439 list_for_each_entry_safe(chunk
, tmp
, &packet
->chunk_list
, list
) {
440 list_del_init(&chunk
->list
);
441 if (sctp_chunk_is_data(chunk
)) {
443 if (!chunk
->has_tsn
) {
444 sctp_chunk_assign_ssn(chunk
);
445 sctp_chunk_assign_tsn(chunk
);
447 /* 6.3.1 C4) When data is in flight and when allowed
448 * by rule C5, a new RTT measurement MUST be made each
449 * round trip. Furthermore, new RTT measurements
450 * SHOULD be made no more than once per round-trip
451 * for a given destination transport address.
454 if (!tp
->rto_pending
) {
455 chunk
->rtt_in_progress
= 1;
464 padding
= WORD_ROUND(chunk
->skb
->len
) - chunk
->skb
->len
;
466 memset(skb_put(chunk
->skb
, padding
), 0, padding
);
468 /* if this is the auth chunk that we are adding,
469 * store pointer where it will be added and put
470 * the auth into the packet.
472 if (chunk
== packet
->auth
)
473 auth
= skb_tail_pointer(nskb
);
475 cksum_buf_len
+= chunk
->skb
->len
;
476 memcpy(skb_put(nskb
, chunk
->skb
->len
),
477 chunk
->skb
->data
, chunk
->skb
->len
);
479 SCTP_DEBUG_PRINTK("%s %p[%s] %s 0x%x, %s %d, %s %d, %s %d\n",
481 sctp_cname(SCTP_ST_CHUNK(
482 chunk
->chunk_hdr
->type
)),
483 chunk
->has_tsn
? "TSN" : "No TSN",
485 ntohl(chunk
->subh
.data_hdr
->tsn
) : 0,
486 "length", ntohs(chunk
->chunk_hdr
->length
),
487 "chunk->skb->len", chunk
->skb
->len
,
488 "rtt_in_progress", chunk
->rtt_in_progress
);
491 * If this is a control chunk, this is our last
492 * reference. Free data chunks after they've been
493 * acknowledged or have failed.
495 if (!sctp_chunk_is_data(chunk
))
496 sctp_chunk_free(chunk
);
499 /* SCTP-AUTH, Section 6.2
500 * The sender MUST calculate the MAC as described in RFC2104 [2]
501 * using the hash function H as described by the MAC Identifier and
502 * the shared association key K based on the endpoint pair shared key
503 * described by the shared key identifier. The 'data' used for the
504 * computation of the AUTH-chunk is given by the AUTH chunk with its
505 * HMAC field set to zero (as shown in Figure 6) followed by all
506 * chunks that are placed after the AUTH chunk in the SCTP packet.
509 sctp_auth_calculate_hmac(asoc
, nskb
,
510 (struct sctp_auth_chunk
*)auth
,
513 /* 2) Calculate the Adler-32 checksum of the whole packet,
514 * including the SCTP common header and all the
517 * Note: Adler-32 is no longer applicable, as has been replaced
518 * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
520 if (!sctp_checksum_disable
&&
521 !(dst
->dev
->features
& (NETIF_F_NO_CSUM
| NETIF_F_SCTP_CSUM
))) {
522 __u32 crc32
= sctp_start_cksum((__u8
*)sh
, cksum_buf_len
);
524 /* 3) Put the resultant value into the checksum field in the
525 * common header, and leave the rest of the bits unchanged.
527 sh
->checksum
= sctp_end_cksum(crc32
);
529 if (dst
->dev
->features
& NETIF_F_SCTP_CSUM
) {
530 /* no need to seed psuedo checksum for SCTP */
531 nskb
->ip_summed
= CHECKSUM_PARTIAL
;
532 nskb
->csum_start
= (skb_transport_header(nskb
) -
534 nskb
->csum_offset
= offsetof(struct sctphdr
, checksum
);
536 nskb
->ip_summed
= CHECKSUM_UNNECESSARY
;
540 /* IP layer ECN support
542 * "The ECN-Capable Transport (ECT) bit would be set by the
543 * data sender to indicate that the end-points of the
544 * transport protocol are ECN-capable."
546 * Now setting the ECT bit all the time, as it should not cause
547 * any problems protocol-wise even if our peer ignores it.
549 * Note: The works for IPv6 layer checks this bit too later
550 * in transmission. See IP6_ECN_flow_xmit().
552 (*tp
->af_specific
->ecn_capable
)(nskb
->sk
);
554 /* Set up the IP options. */
555 /* BUG: not implemented
556 * For v4 this all lives somewhere in sk->sk_opt...
559 /* Dump that on IP! */
560 if (asoc
&& asoc
->peer
.last_sent_to
!= tp
) {
561 /* Considering the multiple CPU scenario, this is a
562 * "correcter" place for last_sent_to. --xguo
564 asoc
->peer
.last_sent_to
= tp
;
568 struct timer_list
*timer
;
569 unsigned long timeout
;
571 tp
->last_time_used
= jiffies
;
573 /* Restart the AUTOCLOSE timer when sending data. */
574 if (sctp_state(asoc
, ESTABLISHED
) && asoc
->autoclose
) {
575 timer
= &asoc
->timers
[SCTP_EVENT_TIMEOUT_AUTOCLOSE
];
576 timeout
= asoc
->timeouts
[SCTP_EVENT_TIMEOUT_AUTOCLOSE
];
578 if (!mod_timer(timer
, jiffies
+ timeout
))
579 sctp_association_hold(asoc
);
583 SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n",
586 nskb
->local_df
= packet
->ipfragok
;
587 (*tp
->af_specific
->sctp_xmit
)(nskb
, tp
);
590 sctp_packet_reset(packet
);
594 IP_INC_STATS_BH(&init_net
, IPSTATS_MIB_OUTNOROUTES
);
596 /* FIXME: Returning the 'err' will effect all the associations
597 * associated with a socket, although only one of the paths of the
598 * association is unreachable.
599 * The real failure of a transport or association can be passed on
600 * to the user via notifications. So setting this error may not be
603 /* err = -EHOSTUNREACH; */
605 /* Control chunks are unreliable so just drop them. DATA chunks
606 * will get resent or dropped later.
609 list_for_each_entry_safe(chunk
, tmp
, &packet
->chunk_list
, list
) {
610 list_del_init(&chunk
->list
);
611 if (!sctp_chunk_is_data(chunk
))
612 sctp_chunk_free(chunk
);
620 /********************************************************************
621 * 2nd Level Abstractions
622 ********************************************************************/
624 /* This private function check to see if a chunk can be added */
625 static sctp_xmit_t
sctp_packet_can_append_data(struct sctp_packet
*packet
,
626 struct sctp_chunk
*chunk
)
628 sctp_xmit_t retval
= SCTP_XMIT_OK
;
629 size_t datasize
, rwnd
, inflight
, flight_size
;
630 struct sctp_transport
*transport
= packet
->transport
;
631 __u32 max_burst_bytes
;
632 struct sctp_association
*asoc
= transport
->asoc
;
633 struct sctp_outq
*q
= &asoc
->outqueue
;
635 /* RFC 2960 6.1 Transmission of DATA Chunks
637 * A) At any given time, the data sender MUST NOT transmit new data to
638 * any destination transport address if its peer's rwnd indicates
639 * that the peer has no buffer space (i.e. rwnd is 0, see Section
640 * 6.2.1). However, regardless of the value of rwnd (including if it
641 * is 0), the data sender can always have one DATA chunk in flight to
642 * the receiver if allowed by cwnd (see rule B below). This rule
643 * allows the sender to probe for a change in rwnd that the sender
644 * missed due to the SACK having been lost in transit from the data
645 * receiver to the data sender.
648 rwnd
= asoc
->peer
.rwnd
;
649 inflight
= q
->outstanding_bytes
;
650 flight_size
= transport
->flight_size
;
652 datasize
= sctp_data_size(chunk
);
654 if (datasize
> rwnd
) {
656 /* We have (at least) one data chunk in flight,
657 * so we can't fall back to rule 6.1 B).
659 retval
= SCTP_XMIT_RWND_FULL
;
664 /* sctpimpguide-05 2.14.2
665 * D) When the time comes for the sender to
666 * transmit new DATA chunks, the protocol parameter Max.Burst MUST
667 * first be applied to limit how many new DATA chunks may be sent.
668 * The limit is applied by adjusting cwnd as follows:
669 * if ((flightsize + Max.Burst * MTU) < cwnd)
670 * cwnd = flightsize + Max.Burst * MTU
672 max_burst_bytes
= asoc
->max_burst
* asoc
->pathmtu
;
673 if ((flight_size
+ max_burst_bytes
) < transport
->cwnd
) {
674 transport
->cwnd
= flight_size
+ max_burst_bytes
;
675 SCTP_DEBUG_PRINTK("%s: cwnd limited by max_burst: "
676 "transport: %p, cwnd: %d, "
677 "ssthresh: %d, flight_size: %d, "
682 transport
->flight_size
,
683 transport
->partial_bytes_acked
);
686 /* RFC 2960 6.1 Transmission of DATA Chunks
688 * B) At any given time, the sender MUST NOT transmit new data
689 * to a given transport address if it has cwnd or more bytes
690 * of data outstanding to that transport address.
692 /* RFC 7.2.4 & the Implementers Guide 2.8.
695 * When a Fast Retransmit is being performed the sender SHOULD
696 * ignore the value of cwnd and SHOULD NOT delay retransmission.
698 if (chunk
->fast_retransmit
!= SCTP_NEED_FRTX
)
699 if (flight_size
>= transport
->cwnd
) {
700 retval
= SCTP_XMIT_RWND_FULL
;
704 /* Nagle's algorithm to solve small-packet problem:
705 * Inhibit the sending of new chunks when new outgoing data arrives
706 * if any previously transmitted data on the connection remains
709 if (!sctp_sk(asoc
->base
.sk
)->nodelay
&& sctp_packet_empty(packet
) &&
710 inflight
&& sctp_state(asoc
, ESTABLISHED
)) {
711 unsigned max
= transport
->pathmtu
- packet
->overhead
;
712 unsigned len
= chunk
->skb
->len
+ q
->out_qlen
;
714 /* Check whether this chunk and all the rest of pending
715 * data will fit or delay in hopes of bundling a full
717 * Don't delay large message writes that may have been
718 * fragmeneted into small peices.
720 if ((len
< max
) && (chunk
->msg
->msg_size
< max
)) {
721 retval
= SCTP_XMIT_NAGLE_DELAY
;
730 /* This private function does management things when adding DATA chunk */
731 static void sctp_packet_append_data(struct sctp_packet
*packet
,
732 struct sctp_chunk
*chunk
)
734 struct sctp_transport
*transport
= packet
->transport
;
735 size_t datasize
= sctp_data_size(chunk
);
736 struct sctp_association
*asoc
= transport
->asoc
;
737 u32 rwnd
= asoc
->peer
.rwnd
;
739 /* Keep track of how many bytes are in flight over this transport. */
740 transport
->flight_size
+= datasize
;
742 /* Keep track of how many bytes are in flight to the receiver. */
743 asoc
->outqueue
.outstanding_bytes
+= datasize
;
745 /* Update our view of the receiver's rwnd. Include sk_buff overhead
746 * while updating peer.rwnd so that it reduces the chances of a
747 * receiver running out of receive buffer space even when receive
748 * window is still open. This can happen when a sender is sending
749 * sending small messages.
751 datasize
+= sizeof(struct sk_buff
);
757 asoc
->peer
.rwnd
= rwnd
;
758 /* Has been accepted for transmission. */
759 if (!asoc
->peer
.prsctp_capable
)
760 chunk
->msg
->can_abandon
= 0;
763 static sctp_xmit_t
sctp_packet_will_fit(struct sctp_packet
*packet
,
764 struct sctp_chunk
*chunk
,
770 sctp_xmit_t retval
= SCTP_XMIT_OK
;
772 psize
= packet
->size
;
773 pmtu
= ((packet
->transport
->asoc
) ?
774 (packet
->transport
->asoc
->pathmtu
) :
775 (packet
->transport
->pathmtu
));
777 too_big
= (psize
+ chunk_len
> pmtu
);
779 /* Decide if we need to fragment or resubmit later. */
781 /* It's OK to fragmet at IP level if any one of the following
783 * 1. The packet is empty (meaning this chunk is greater
785 * 2. The chunk we are adding is a control chunk
786 * 3. The packet doesn't have any data in it yet and data
787 * requires authentication.
789 if (sctp_packet_empty(packet
) || !sctp_chunk_is_data(chunk
) ||
790 (!packet
->has_data
&& chunk
->auth
)) {
791 /* We no longer do re-fragmentation.
792 * Just fragment at the IP layer, if we
793 * actually hit this condition
795 packet
->ipfragok
= 1;
797 retval
= SCTP_XMIT_PMTU_FULL
;