static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff_head *list = &sk->sk_receive_queue;
if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
return -ENOMEM;
if (!sk_rmem_schedule(sk, skb, skb->truesize))
return -ENOBUFS;
skb->dev = NULL;
skb_orphan(skb);
skb->sk = sk;
skb->destructor = kcm_rfree;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_charge(sk, skb->truesize);
skb_queue_tail(list, skb);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
return 0;
}
/* 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;
}
