sctp: drop SHUTDOWN chunk if the TSN is less than the CTSN

If Cumulative TSN Ack field of SHUTDOWN chunk is less than the
Cumulative TSN Ack Point then drop the SHUTDOWN chunk.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 910926906a3ac19f2f00ab97abb1da737490f047..73bdeb2b6c62302f0fe8ef0621b5ac2b6383723f 100644 (file)
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2570,6 +2570,12 @@ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep,
        chunk->subh.shutdown_hdr = sdh;
        ctsn = ntohl(sdh->cum_tsn_ack);
 
+       if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
+               SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
+               SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
+               return SCTP_DISPOSITION_DISCARD;
+       }
+
        /* If Cumulative TSN Ack beyond the max tsn currently
         * send, terminating the association and respond to the
         * sender with an ABORT.
@@ -2633,6 +2639,7 @@ sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
 {
        struct sctp_chunk *chunk = arg;
        sctp_shutdownhdr_t *sdh;
+       __u32 ctsn;
 
        if (!sctp_vtag_verify(chunk, asoc))
                return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
@@ -2644,12 +2651,19 @@ sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep,
                                                  commands);
 
        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
+       ctsn = ntohl(sdh->cum_tsn_ack);
+
+       if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
+               SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn);
+               SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point);
+               return SCTP_DISPOSITION_DISCARD;
+       }
 
        /* If Cumulative TSN Ack beyond the max tsn currently
         * send, terminating the association and respond to the
         * sender with an ABORT.
         */
-       if (!TSN_lt(ntohl(sdh->cum_tsn_ack), asoc->next_tsn))
+       if (!TSN_lt(ctsn, asoc->next_tsn))
                return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands);
 
        /* verify, by checking the Cumulative TSN Ack field of the