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-rw-r--r--net/sctp/chunk.c32
1 files changed, 23 insertions, 9 deletions
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 1748ef90950c..9292294dbc12 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -158,6 +158,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
{
int max, whole, i, offset, over, err;
int len, first_len;
+ int max_data;
struct sctp_chunk *chunk;
struct sctp_datamsg *msg;
struct list_head *pos, *temp;
@@ -179,8 +180,14 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
__func__, msg, msg->expires_at, jiffies);
}
- max = asoc->frag_point;
+ /* This is the biggest possible DATA chunk that can fit into
+ * the packet
+ */
+ max_data = asoc->pathmtu -
+ sctp_sk(asoc->base.sk)->pf->af->net_header_len -
+ sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
+ max = asoc->frag_point;
/* If the the peer requested that we authenticate DATA chunks
* we need to accound for bundling of the AUTH chunks along with
* DATA.
@@ -189,23 +196,30 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
if (hmac_desc)
- max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
+ max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
hmac_desc->hmac_len);
}
+ /* Now, check if we need to reduce our max */
+ if (max > max_data)
+ max = max_data;
+
whole = 0;
first_len = max;
/* Encourage Cookie-ECHO bundling. */
if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
- whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
+ max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
- /* Account for the DATA to be bundled with the COOKIE-ECHO. */
- if (whole) {
- first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
- msg_len -= first_len;
- whole = 1;
- }
+ /* This is the biggesr first_len we can have */
+ if (first_len > max_data)
+ first_len = max_data;
+ }
+
+ /* Account for a different sized first fragment */
+ if (msg_len >= first_len) {
+ msg_len -= first_len;
+ whole = 1;
}
/* How many full sized? How many bytes leftover? */
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