diff options
| -rw-r--r-- | net/sctp/chunk.c | 32 |
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? */ |