[SCTP]: Update ASCONF processing to conform to spec.
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>
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 8a0808e..fa87873 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -744,6 +744,7 @@
__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_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 @@
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);
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 61bebb9..a016e78 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -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 @@
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 @@
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 @@
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;
+}
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index fa76f23..a42af86 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -716,7 +716,29 @@
new_transport = chunk->transport;
if (!new_transport) {
- new_transport = asoc->peer.active_path;
+ /*
+ * 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)) {
/* If the chunk is Heartbeat or Heartbeat Ack,
@@ -729,9 +751,12 @@
* 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;
}
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 8138bbd..7fd6a6b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1275,6 +1275,9 @@
/* 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 @@
/* 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 @@
* 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;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b6aaa7e..a1be9d9 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -3402,48 +3402,68 @@
/* Verify the ASCONF chunk before processing it. */
if (!sctp_verify_asconf(asoc,
- (sctp_paramhdr_t *)((void *)addr_param + length),
- (void *)chunk->chunk_end,
- &err_param))
+ (sctp_paramhdr_t *)((void *)addr_param + length),
+ (void *)chunk->chunk_end,
+ &err_param))
return sctp_sf_violation_paramlen(ep, asoc, type,
- (void *)&err_param, commands);
+ (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;