[SCTP] Implement Sec 2.41 of SCTP Implementers guide.
- Fixed sctp_vtag_verify_either() to comply with impguide 2.41 B) and C).
- Make sure vtag is reflected when T-bit is set in SHUTDOWN-COMPLETE sent
due to an OOTB SHUTDOWN-ACK and in ABORT sent due to an OOTB packet.
- Do not set T-Bit in ABORT chunk in response to INIT.
- Fixed some comments to reflect the new meaning of the T-Bit.
Signed-off-by: Jerome Forissier <jerome.forissier@xxxxxx>
Signed-off-by: Sridhar Samudrala <sri@xxxxxxxxxx>
--------------------------------------------------------------------------
diff -Nru a/include/net/sctp/sm.h b/include/net/sctp/sm.h
--- a/include/net/sctp/sm.h 2005-04-21 16:20:59 -07:00
+++ b/include/net/sctp/sm.h 2005-04-21 16:20:59 -07:00
@@ -407,32 +407,38 @@
return 0;
}
-/* Check VTAG of the packet matches the sender's own tag OR its peer's
- * tag and the T bit is set in the Chunk Flags.
+/* Check VTAG of the packet matches the sender's own tag and the T bit is
+ * not set, OR its peer's tag and the T bit is set in the Chunk Flags.
*/
static inline int
sctp_vtag_verify_either(const struct sctp_chunk *chunk,
const struct sctp_association *asoc)
{
- /* RFC 2960 Section 8.5.1, sctpimpguide-06 Section 2.13.2
+ /* RFC 2960 Section 8.5.1, sctpimpguide Section 2.41
*
- * B) The receiver of a ABORT shall accept the packet if the
- * Verification Tag field of the packet matches its own tag OR it
- * is set to its peer's tag and the T bit is set in the Chunk
- * Flags. Otherwise, the receiver MUST silently discard the packet
- * and take no further action.
- *
- * (C) The receiver of a SHUTDOWN COMPLETE shall accept the
- * packet if the Verification Tag field of the packet
- * matches its own tag OR it is set to its peer's tag and
- * the T bit is set in the Chunk Flags. Otherwise, the
- * receiver MUST silently discard the packet and take no
- * further action....
+ * B) The receiver of a ABORT MUST accept the packet
+ * if the Verification Tag field of the packet matches its own tag
+ * and the T bit is not set
+ * OR
+ * it is set to its peer's tag and the T bit is set in the Chunk
+ * Flags.
+ * Otherwise, the receiver MUST silently discard the packet
+ * and take no further action.
*
+ * C) The receiver of a SHUTDOWN COMPLETE shall accept the packet
+ * if the Verification Tag field of the packet matches its own tag
+ * and the T bit is not set
+ * OR
+ * it is set to its peer's tag and the T bit is set in the Chunk
+ * Flags.
+ * Otherwise, the receiver MUST silently discard the packet
+ * and take no further action. An endpoint MUST ignore the
+ * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
*/
- if ((ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag) ||
- (sctp_test_T_bit(chunk) && (ntohl(chunk->sctp_hdr->vtag)
- == asoc->c.peer_vtag))) {
+ if ((!sctp_test_T_bit(chunk) &&
+ (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)) ||
+ (sctp_test_T_bit(chunk) &&
+ (ntohl(chunk->sctp_hdr->vtag) == asoc->c.peer_vtag))) {
return 1;
}
diff -Nru a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
--- a/net/sctp/sm_make_chunk.c 2005-04-21 16:20:59 -07:00
+++ b/net/sctp/sm_make_chunk.c 2005-04-21 16:20:59 -07:00
@@ -710,7 +710,9 @@
struct sctp_chunk *retval;
__u8 flags = 0;
- /* Maybe set the T-bit if we have no association. */
+ /* Set the T-bit if we have no association (vtag will be
+ * reflected)
+ */
flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
@@ -732,7 +734,7 @@
}
/* Create an ABORT. Note that we set the T bit if we have no
- * association.
+ * association, except when responding to an INIT (sctpimpguide 2.41).
*/
struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
const struct sctp_chunk *chunk,
@@ -741,8 +743,16 @@
struct sctp_chunk *retval;
__u8 flags = 0;
- /* Maybe set the T-bit if we have no association. */
- flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
+ /* Set the T-bit if we have no association and 'chunk' is not
+ * an INIT (vtag will be reflected).
+ */
+ if (!asoc) {
+ if (chunk && chunk->chunk_hdr &&
+ chunk->chunk_hdr->type == SCTP_CID_INIT)
+ flags = 0;
+ else
+ flags = SCTP_CHUNK_FLAG_T;
+ }
retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
@@ -2744,7 +2754,6 @@
hint = (nstreams + 1) * sizeof(__u32);
- /* Maybe set the T-bit if we have no association. */
retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);
if (!retval)
diff -Nru a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
--- a/net/sctp/sm_statefuns.c 2005-04-21 16:20:59 -07:00
+++ b/net/sctp/sm_statefuns.c 2005-04-21 16:20:59 -07:00
@@ -126,15 +126,18 @@
* should stop the T2-shutdown timer and remove all knowledge of the
* association (and thus the association enters the CLOSED state).
*
- * Verification Tag: 8.5.1(C)
+ * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
* C) Rules for packet carrying SHUTDOWN COMPLETE:
* ...
- * - The receiver of a SHUTDOWN COMPLETE shall accept the packet if the
- * Verification Tag field of the packet matches its own tag OR it is
- * set to its peer's tag and the T bit is set in the Chunk Flags.
- * Otherwise, the receiver MUST silently discard the packet and take
- * no further action. An endpoint MUST ignore the SHUTDOWN COMPLETE if
- * it is not in the SHUTDOWN-ACK-SENT state.
+ * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
+ * if the Verification Tag field of the packet matches its own tag and
+ * the T bit is not set
+ * OR
+ * it is set to its peer's tag and the T bit is set in the Chunk
+ * Flags.
+ * Otherwise, the receiver MUST silently discard the packet
+ * and take no further action. An endpoint MUST ignore the
+ * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
*
* Inputs
* (endpoint, asoc, chunk)
@@ -2858,16 +2861,16 @@
/*
* Generate an ABORT in response to a packet.
*
- * Section: 8.4 Handle "Out of the blue" Packets
+ * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
*
- * 8) The receiver should respond to the sender of the OOTB packet
- * with an ABORT. When sending the ABORT, the receiver of the
- * OOTB packet MUST fill in the Verification Tag field of the
- * outbound packet with the value found in the Verification Tag
- * field of the OOTB packet and set the T-bit in the Chunk Flags
- * to indicate that no TCB was found. After sending this ABORT,
- * the receiver of the OOTB packet shall discard the OOTB packet
- * and take no further action.
+ * 8) The receiver should respond to the sender of the OOTB packet with
+ * an ABORT. When sending the ABORT, the receiver of the OOTB packet
+ * MUST fill in the Verification Tag field of the outbound packet
+ * with the value found in the Verification Tag field of the OOTB
+ * packet and set the T-bit in the Chunk Flags to indicate that the
+ * Verification Tag is reflected. After sending this ABORT, the
+ * receiver of the OOTB packet shall discard the OOTB packet and take
+ * no further action.
*
* Verification Tag:
*
@@ -2895,6 +2898,10 @@
return SCTP_DISPOSITION_NOMEM;
}
+ /* Reflect vtag if T-Bit is set */
+ if (sctp_test_T_bit(abort))
+ packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
/* Set the skb to the belonging sock for accounting. */
abort->skb->sk = ep->base.sk;
@@ -3026,22 +3033,24 @@
}
/*
- * RFC 2960, 8.4 - Handle "Out of the blue" Packets
+ * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
+ *
* 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
* respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
* When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
* packet must fill in the Verification Tag field of the outbound
* packet with the Verification Tag received in the SHUTDOWN ACK and
- * set the T-bit in the Chunk Flags to indicate that no TCB was
- * found. Otherwise,
+ * set the T-bit in the Chunk Flags to indicate that the Verification
+ * Tag is reflected.
*
* 8) The receiver should respond to the sender of the OOTB packet with
* an ABORT. When sending the ABORT, the receiver of the OOTB packet
* MUST fill in the Verification Tag field of the outbound packet
* with the value found in the Verification Tag field of the OOTB
- * packet and set the T-bit in the Chunk Flags to indicate that no
- * TCB was found. After sending this ABORT, the receiver of the OOTB
- * packet shall discard the OOTB packet and take no further action.
+ * packet and set the T-bit in the Chunk Flags to indicate that the
+ * Verification Tag is reflected. After sending this ABORT, the
+ * receiver of the OOTB packet shall discard the OOTB packet and take
+ * no further action.
*/
sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
@@ -3090,13 +3099,15 @@
/*
* Handle an "Out of the blue" SHUTDOWN ACK.
*
- * Section: 8.4 5)
+ * Section: 8.4 5, sctpimpguide 2.41.
+ *
* 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
- * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
- * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB packet
- * must fill in the Verification Tag field of the outbound packet with
- * the Verification Tag received in the SHUTDOWN ACK and set the
- * T-bit in the Chunk Flags to indicate that no TCB was found.
+ * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
+ * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
+ * packet must fill in the Verification Tag field of the outbound
+ * packet with the Verification Tag received in the SHUTDOWN ACK and
+ * set the T-bit in the Chunk Flags to indicate that the Verification
+ * Tag is reflected.
*
* Inputs
* (endpoint, asoc, type, arg, commands)
@@ -3128,6 +3139,10 @@
return SCTP_DISPOSITION_NOMEM;
}
+ /* Reflect vtag if T-Bit is set */
+ if (sctp_test_T_bit(shut))
+ packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
/* Set the skb to the belonging sock for accounting. */
shut->skb->sk = ep->base.sk;
@@ -3591,7 +3606,6 @@
*
* 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
* silently discard the OOTB packet and take no further action.
- * Otherwise,
*
* Verification Tag: No verification necessary
*
@@ -4961,6 +4975,11 @@
sctp_ootb_pkt_free(packet);
return NULL;
}
+
+ /* Reflect vtag if T-Bit is set */
+ if (sctp_test_T_bit(abort))
+ packet->vtag = ntohl(chunk->sctp_hdr->vtag);
+
/* Add specified error causes, i.e., payload, to the
* end of the chunk.
*/
|