/* Make a SHUTDOWN chunk. */
struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
const struct sctp_chunk *chunk)
{
struct sctp_chunk *retval;
sctp_shutdownhdr_t shut;
__u32 ctsn;
ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
shut.cum_tsn_ack = htonl(ctsn);
retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
sizeof(sctp_shutdownhdr_t));
if (!retval)
goto nodata;
retval->subh.shutdown_hdr =
sctp_addto_chunk(retval, sizeof(shut), &shut);
if (chunk)
retval->transport = chunk->transport;
nodata:
return retval;
}
/* A message has been received. Package this message as a notification
* to pass it to the upper layers. Go ahead and calculate the sndrcvinfo
* even if filtered out later.
*
* Socket Extensions for SCTP
* 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
*/
struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
struct sctp_chunk *chunk,
gfp_t gfp)
{
struct sctp_ulpevent *event = NULL;
struct sk_buff *skb;
size_t padding, len;
int rx_count;
/*
* check to see if we need to make space for this
* new skb, expand the rcvbuffer if needed, or drop
* the frame
*/
if (asoc->ep->rcvbuf_policy)
rx_count = atomic_read(&asoc->rmem_alloc);
else
rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
if (rx_count >= asoc->base.sk->sk_rcvbuf) {
if ((asoc->base.sk->sk_userlocks & SOCK_RCVBUF_LOCK) ||
(!sk_rmem_schedule(asoc->base.sk, chunk->skb->truesize)))
goto fail;
}
/* Clone the original skb, sharing the data. */
skb = skb_clone(chunk->skb, gfp);
if (!skb)
goto fail;
/* Now that all memory allocations for this chunk succeeded, we
* can mark it as received so the tsn_map is updated correctly.
*/
if (sctp_tsnmap_mark(&asoc->peer.tsn_map,
ntohl(chunk->subh.data_hdr->tsn)))
goto fail_mark;
/* First calculate the padding, so we don't inadvertently
* pass up the wrong length to the user.
*
* RFC 2960 - Section 3.2 Chunk Field Descriptions
*
* The total length of a chunk(including Type, Length and Value fields)
* MUST be a multiple of 4 bytes. If the length of the chunk is not a
* multiple of 4 bytes, the sender MUST pad the chunk with all zero
* bytes and this padding is not included in the chunk length field.
* The sender should never pad with more than 3 bytes. The receiver
* MUST ignore the padding bytes.
*/
len = ntohs(chunk->chunk_hdr->length);
padding = WORD_ROUND(len) - len;
/* Fixup cloned skb with just this chunks data. */
skb_trim(skb, chunk->chunk_end - padding - skb->data);
/* Embed the event fields inside the cloned skb. */
event = sctp_skb2event(skb);
/* Initialize event with flags 0 and correct length
* Since this is a clone of the original skb, only account for
* the data of this chunk as other chunks will be accounted separately.
*/
sctp_ulpevent_init(event, 0, skb->len + sizeof(struct sk_buff));
sctp_ulpevent_receive_data(event, asoc);
event->stream = ntohs(chunk->subh.data_hdr->stream);
event->ssn = ntohs(chunk->subh.data_hdr->ssn);
event->ppid = chunk->subh.data_hdr->ppid;
if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
event->flags |= SCTP_UNORDERED;
event->cumtsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
}
event->tsn = ntohl(chunk->subh.data_hdr->tsn);
event->msg_flags |= chunk->chunk_hdr->flags;
event->iif = sctp_chunk_iif(chunk);
return event;
fail_mark:
kfree_skb(skb);
fail:
return NULL;
}
/* Create a selective ackowledgement (SACK) for the given
* association. This reports on which TSN's we've seen to date,
* including duplicates and gaps.
*/
struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
{
struct sctp_chunk *retval;
struct sctp_sackhdr sack;
int len;
__u32 ctsn;
__u16 num_gabs, num_dup_tsns;
struct sctp_association *aptr = (struct sctp_association *)asoc;
struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
struct sctp_transport *trans;
memset(gabs, 0, sizeof(gabs));
ctsn = sctp_tsnmap_get_ctsn(map);
pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
/* How much room is needed in the chunk? */
num_gabs = sctp_tsnmap_num_gabs(map, gabs);
num_dup_tsns = sctp_tsnmap_num_dups(map);
/* Initialize the SACK header. */
sack.cum_tsn_ack = htonl(ctsn);
sack.a_rwnd = htonl(asoc->a_rwnd);
sack.num_gap_ack_blocks = htons(num_gabs);
sack.num_dup_tsns = htons(num_dup_tsns);
len = sizeof(sack)
+ sizeof(struct sctp_gap_ack_block) * num_gabs
+ sizeof(__u32) * num_dup_tsns;
/* Create the chunk. */
retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len);
if (!retval)
goto nodata;
/* RFC 2960 6.4 Multi-homed SCTP Endpoints
*
* An endpoint SHOULD transmit reply chunks (e.g., SACK,
* HEARTBEAT ACK, etc.) to the same destination transport
* address from which it received the DATA or control chunk to
* which it is replying. This rule should also be followed if
* the endpoint is bundling DATA chunks together with the
* reply chunk.
*
* However, when acknowledging multiple DATA chunks received
* in packets from different source addresses in a single
* SACK, the SACK chunk may be transmitted to one of the
* destination transport addresses from which the DATA or
* control chunks being acknowledged were received.
*
* [BUG: We do not implement the following paragraph.
* Perhaps we should remember the last transport we used for a
* SACK and avoid that (if possible) if we have seen any
* duplicates. --piggy]
*
* When a receiver of a duplicate DATA chunk sends a SACK to a
* multi- homed endpoint it MAY be beneficial to vary the
* destination address and not use the source address of the
* DATA chunk. The reason being that receiving a duplicate
* from a multi-homed endpoint might indicate that the return
* path (as specified in the source address of the DATA chunk)
* for the SACK is broken.
*
* [Send to the address from which we last received a DATA chunk.]
*/
retval->transport = asoc->peer.last_data_from;
retval->subh.sack_hdr =
sctp_addto_chunk(retval, sizeof(sack), &sack);
/* Add the gap ack block information. */
if (num_gabs)
sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
gabs);
/* Add the duplicate TSN information. */
if (num_dup_tsns) {
aptr->stats.idupchunks += num_dup_tsns;
sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
sctp_tsnmap_get_dups(map));
}
/* Once we have a sack generated, check to see what our sack
* generation is, if its 0, reset the transports to 0, and reset
* the association generation to 1
*
* The idea is that zero is never used as a valid generation for the
* association so no transport will match after a wrap event like this,
* Until the next sack
*/
if (++aptr->peer.sack_generation == 0) {
list_for_each_entry(trans, &asoc->peer.transport_addr_list,
transports)
trans->sack_generation = 0;
aptr->peer.sack_generation = 1;
}
nodata:
return retval;
}
struct sctp_chunk *sctp_process_strreset_outreq(
struct sctp_association *asoc,
union sctp_params param,
struct sctp_ulpevent **evp)
{
struct sctp_strreset_outreq *outreq = param.v;
struct sctp_stream *stream = asoc->stream;
__u16 i, nums, flags = 0, *str_p = NULL;
__u32 result = SCTP_STRRESET_DENIED;
__u32 request_seq;
request_seq = ntohl(outreq->request_seq);
if (ntohl(outreq->send_reset_at_tsn) >
sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)) {
result = SCTP_STRRESET_IN_PROGRESS;
goto out;
}
if (request_seq > asoc->strreset_inseq) {
result = SCTP_STRRESET_ERR_BAD_SEQNO;
goto out;
} else if (request_seq == asoc->strreset_inseq) {
asoc->strreset_inseq++;
}
/* Check strreset_enable after inseq inc, as sender cannot tell
* the peer doesn't enable strreset after receiving response with
* result denied, as well as to keep consistent with bsd.
*/
if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
goto out;
if (asoc->strreset_chunk) {
sctp_paramhdr_t *param_hdr;
struct sctp_transport *t;
param_hdr = sctp_chunk_lookup_strreset_param(
asoc, outreq->response_seq);
if (!param_hdr || param_hdr->type !=
SCTP_PARAM_RESET_IN_REQUEST) {
/* same process with outstanding isn't 0 */
result = SCTP_STRRESET_ERR_IN_PROGRESS;
goto out;
}
asoc->strreset_outstanding--;
asoc->strreset_outseq++;
if (!asoc->strreset_outstanding) {
t = asoc->strreset_chunk->transport;
if (del_timer(&t->reconf_timer))
sctp_transport_put(t);
sctp_chunk_put(asoc->strreset_chunk);
asoc->strreset_chunk = NULL;
}
flags = SCTP_STREAM_RESET_INCOMING_SSN;
}
nums = (ntohs(param.p->length) - sizeof(*outreq)) / 2;
if (nums) {
str_p = outreq->list_of_streams;
for (i = 0; i < nums; i++) {
if (ntohs(str_p[i]) >= stream->incnt) {
result = SCTP_STRRESET_ERR_WRONG_SSN;
goto out;
}
}
for (i = 0; i < nums; i++)
stream->in[ntohs(str_p[i])].ssn = 0;
} else {
for (i = 0; i < stream->incnt; i++)
stream->in[i].ssn = 0;
}
result = SCTP_STRRESET_PERFORMED;
*evp = sctp_ulpevent_make_stream_reset_event(asoc,
flags | SCTP_STREAM_RESET_OUTGOING_SSN, nums, str_p,
GFP_ATOMIC);
out:
return sctp_make_strreset_resp(asoc, result, request_seq);
}
