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[SCTP]: Update ASCONF processing to conform to spec.

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The processing of the ASCONF chunks has changed a lot in the
spec.  New items are:
    1. A list of ASCONF-ACK chunks is now cached
    2. The source of the packet is used in response.
    3. New handling for unexpect ASCONF chunks.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Yasevich 2007-12-20 14:11:47 -08:00 committed by David S. Miller
parent ba8a06daed
commit a08de64d07
5 changed files with 143 additions and 44 deletions
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24
include/net/sctp/structs.h
View file

@ -744,6 +744,7 @@ struct sctp_chunk {
__u8 tsn_missing_report; /* Data chunk missing counter. */
__u8 data_accepted; /* At least 1 chunk in this packet accepted */
__u8 auth; /* IN: was auth'ed | OUT: needs auth */
__u8 has_asconf; /* IN: have seen an asconf before */
};
void sctp_chunk_hold(struct sctp_chunk *);
@ -1785,20 +1786,16 @@ struct sctp_association {
*/
struct sctp_chunk *addip_last_asconf;
/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
*
* IMPLEMENTATION NOTE: As an optimization a receiver may wish
* to save the last ASCONF-ACK for some predetermined period
* of time and instead of re-processing the ASCONF (with the
* same serial number) it may just re-transmit the
* ASCONF-ACK. It may wish to use the arrival of a new serial
* number to discard the previously saved ASCONF-ACK or any
* other means it may choose to expire the saved ASCONF-ACK.
* This is needed to implement itmes E1 - E4 of the updated
* spec. Here is the justification:
*
* [This is our saved ASCONF-ACK. We invalidate it when a new
* ASCONF serial number arrives.]
* Since the peer may bundle multiple ASCONF chunks toward us,
* we now need the ability to cache multiple ACKs. The section
* describes in detail how they are cached and cleaned up.
*/
struct sctp_chunk *addip_last_asconf_ack;
struct list_head asconf_ack_list;
/* These ASCONF chunks are waiting to be sent.
*
@ -1947,6 +1944,11 @@ int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
struct sctp_cookie*,
gfp_t gfp);
int sctp_assoc_set_id(struct sctp_association *, gfp_t);
void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
const struct sctp_association *asoc,
__be32 serial);
int sctp_cmp_addr_exact(const union sctp_addr *ss1,
const union sctp_addr *ss2);

58
net/sctp/associola.c
View file

@ -61,6 +61,7 @@
/* Forward declarations for internal functions. */
static void sctp_assoc_bh_rcv(struct work_struct *work);
static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
/* 1st Level Abstractions. */
@ -242,6 +243,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
asoc->addip_serial = asoc->c.initial_tsn;
INIT_LIST_HEAD(&asoc->addip_chunk_list);
INIT_LIST_HEAD(&asoc->asconf_ack_list);
/* Make an empty list of remote transport addresses. */
INIT_LIST_HEAD(&asoc->peer.transport_addr_list);
@ -431,8 +433,7 @@ void sctp_association_free(struct sctp_association *asoc)
asoc->peer.transport_count = 0;
/* Free any cached ASCONF_ACK chunk. */
if (asoc->addip_last_asconf_ack)
sctp_chunk_free(asoc->addip_last_asconf_ack);
sctp_assoc_free_asconf_acks(asoc);
/* Free any cached ASCONF chunk. */
if (asoc->addip_last_asconf)
@ -1485,3 +1486,56 @@ retry:
asoc->assoc_id = (sctp_assoc_t) assoc_id;
return error;
}
/* Free asconf_ack cache */
static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc)
{
struct sctp_chunk *ack;
struct sctp_chunk *tmp;
list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
transmitted_list) {
list_del_init(&ack->transmitted_list);
sctp_chunk_free(ack);
}
}
/* Clean up the ASCONF_ACK queue */
void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc)
{
struct sctp_chunk *ack;
struct sctp_chunk *tmp;
/* We can remove all the entries from the queue upto
* the "Peer-Sequence-Number".
*/
list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list,
transmitted_list) {
if (ack->subh.addip_hdr->serial ==
htonl(asoc->peer.addip_serial))
break;
list_del_init(&ack->transmitted_list);
sctp_chunk_free(ack);
}
}
/* Find the ASCONF_ACK whose serial number matches ASCONF */
struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
const struct sctp_association *asoc,
__be32 serial)
{
struct sctp_chunk *ack = NULL;
/* Walk through the list of cached ASCONF-ACKs and find the
* ack chunk whose serial number matches that of the request.
*/
list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) {
if (ack->subh.addip_hdr->serial == serial) {
sctp_chunk_hold(ack);
break;
}
}
return ack;
}

27
net/sctp/outqueue.c
View file

@ -716,6 +716,28 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
new_transport = chunk->transport;
if (!new_transport) {
/*
* If we have a prior transport pointer, see if
* the destination address of the chunk
* matches the destination address of the
* current transport. If not a match, then
* try to look up the transport with a given
* destination address. We do this because
* after processing ASCONFs, we may have new
* transports created.
*/
if (transport &&
sctp_cmp_addr_exact(&chunk->dest,
&transport->ipaddr))
new_transport = transport;
else
new_transport = sctp_assoc_lookup_paddr(asoc,
&chunk->dest);
/* if we still don't have a new transport, then
* use the current active path.
*/
if (!new_transport)
new_transport = asoc->peer.active_path;
} else if ((new_transport->state == SCTP_INACTIVE) ||
(new_transport->state == SCTP_UNCONFIRMED)) {
@ -729,9 +751,12 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
* address of the IP datagram containing the
* HEARTBEAT chunk to which this ack is responding.
* ...
*
* ASCONF_ACKs also must be sent to the source.
*/
if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
new_transport = asoc->peer.active_path;
}

12
net/sctp/sm_make_chunk.c
View file

@ -1275,6 +1275,9 @@ nodata:
/* Release the memory occupied by a chunk. */
static void sctp_chunk_destroy(struct sctp_chunk *chunk)
{
BUG_ON(!list_empty(&chunk->list));
list_del_init(&chunk->transmitted_list);
/* Free the chunk skb data and the SCTP_chunk stub itself. */
dev_kfree_skb(chunk->skb);
@ -1285,9 +1288,6 @@ static void sctp_chunk_destroy(struct sctp_chunk *chunk)
/* Possibly, free the chunk. */
void sctp_chunk_free(struct sctp_chunk *chunk)
{
BUG_ON(!list_empty(&chunk->list));
list_del_init(&chunk->transmitted_list);
/* Release our reference on the message tracker. */
if (chunk->msg)
sctp_datamsg_put(chunk->msg);
@ -2980,11 +2980,9 @@ done:
* after freeing the reference to old asconf ack if any.
*/
if (asconf_ack) {
if (asoc->addip_last_asconf_ack)
sctp_chunk_free(asoc->addip_last_asconf_ack);
sctp_chunk_hold(asconf_ack);
asoc->addip_last_asconf_ack = asconf_ack;
list_add_tail(&asconf_ack->transmitted_list,
&asoc->asconf_ack_list);
}
return asconf_ack;

56
net/sctp/sm_statefuns.c
View file

@ -3408,42 +3408,62 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
return sctp_sf_violation_paramlen(ep, asoc, type,
(void *)&err_param, commands);
/* ADDIP 4.2 C1) Compare the value of the serial number to the value
/* ADDIP 5.2 E1) Compare the value of the serial number to the value
* the endpoint stored in a new association variable
* 'Peer-Serial-Number'.
*/
if (serial == asoc->peer.addip_serial + 1) {
/* ADDIP 4.2 C2) If the value found in the serial number is
* equal to the ('Peer-Serial-Number' + 1), the endpoint MUST
* do V1-V5.
/* If this is the first instance of ASCONF in the packet,
* we can clean our old ASCONF-ACKs.
*/
if (!chunk->has_asconf)
sctp_assoc_clean_asconf_ack_cache(asoc);
/* ADDIP 5.2 E4) When the Sequence Number matches the next one
* expected, process the ASCONF as described below and after
* processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
* the response packet and cache a copy of it (in the event it
* later needs to be retransmitted).
*
* Essentially, do V1-V5.
*/
asconf_ack = sctp_process_asconf((struct sctp_association *)
asoc, chunk);
if (!asconf_ack)
return SCTP_DISPOSITION_NOMEM;
} else if (serial == asoc->peer.addip_serial) {
/* ADDIP 4.2 C3) If the value found in the serial number is
* equal to the value stored in the 'Peer-Serial-Number'
* IMPLEMENTATION NOTE: As an optimization a receiver may wish
* to save the last ASCONF-ACK for some predetermined period of
* time and instead of re-processing the ASCONF (with the same
* serial number) it may just re-transmit the ASCONF-ACK.
} else if (serial < asoc->peer.addip_serial + 1) {
/* ADDIP 5.2 E2)
* If the value found in the Sequence Number is less than the
* ('Peer- Sequence-Number' + 1), simply skip to the next
* ASCONF, and include in the outbound response packet
* any previously cached ASCONF-ACK response that was
* sent and saved that matches the Sequence Number of the
* ASCONF. Note: It is possible that no cached ASCONF-ACK
* Chunk exists. This will occur when an older ASCONF
* arrives out of order. In such a case, the receiver
* should skip the ASCONF Chunk and not include ASCONF-ACK
* Chunk for that chunk.
*/
if (asoc->addip_last_asconf_ack)
asconf_ack = asoc->addip_last_asconf_ack;
else
asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
if (!asconf_ack)
return SCTP_DISPOSITION_DISCARD;
} else {
/* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since
/* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
* it must be either a stale packet or from an attacker.
*/
return SCTP_DISPOSITION_DISCARD;
}
/* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent
* back to the source address contained in the IP header of the ASCONF
* being responded to.
/* ADDIP 5.2 E6) The destination address of the SCTP packet
* containing the ASCONF-ACK Chunks MUST be the source address of
* the SCTP packet that held the ASCONF Chunks.
*
* To do this properly, we'll set the destination address of the chunk
* and at the transmit time, will try look up the transport to use.
* Since ASCONFs may be bundled, the correct transport may not be
* created untill we process the entire packet, thus this workaround.
*/
asconf_ack->dest = chunk->source;
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
return SCTP_DISPOSITION_CONSUME;