sctp: add asoc intl_enable negotiation during 4 shakehands

asoc intl_enable will be set when local sp strm_interleave is set
and there's I-DATA chunk in init and init_ack extensions, as said
in section 2.2.1 of RFC8260.

asoc intl_enable indicates all data will be sent as I-DATA chunks.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 2 deletions

diff --git a/include/linux/sctp.h b/include/linux/sctp.h
index da803dfc7a39..6d2bd64b6ffe 100644
--- a/include/linux/sctp.h
+++ b/include/linux/sctp.h
@@ -102,6 +102,9 @@ enum sctp_cid {
         /* AUTH Extension Section 4.1 */
         SCTP_CID_AUTH                   = 0x0F,
 
+        /* sctp ndata 5.1. I-DATA */
+        SCTP_CID_I_DATA                 = 0x40,
+
         /* PR-SCTP Sec 3.2 */
         SCTP_CID_FWD_TSN                = 0xC0,
 
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 9bf575f2e8ed..da33c8550170 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -228,7 +228,7 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
         struct sctp_inithdr init;
         union sctp_params addrs;
         struct sctp_sock *sp;
-        __u8 extensions[4];
+        __u8 extensions[5];
         size_t chunksize;
         __be16 types[2];
         int num_ext = 0;
@@ -278,6 +278,11 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
         if (sp->adaptation_ind)
                 chunksize += sizeof(aiparam);
 
+        if (sp->strm_interleave) {
+                extensions[num_ext] = SCTP_CID_I_DATA;
+                num_ext += 1;
+        }
+
         chunksize += vparam_len;
 
         /* Account for AUTH related parameters */
@@ -392,7 +397,7 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
         struct sctp_inithdr initack;
         union sctp_params addrs;
         struct sctp_sock *sp;
-        __u8 extensions[4];
+        __u8 extensions[5];
         size_t chunksize;
         int num_ext = 0;
         int cookie_len;
@@ -442,6 +447,11 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
         if (sp->adaptation_ind)
                 chunksize += sizeof(aiparam);
 
+        if (asoc->intl_enable) {
+                extensions[num_ext] = SCTP_CID_I_DATA;
+                num_ext += 1;
+        }
+
         if (asoc->peer.auth_capable) {
                 auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
                 chunksize += ntohs(auth_random->length);
@@ -2032,6 +2042,10 @@ static void sctp_process_ext_param(struct sctp_association *asoc,
                         if (net->sctp.addip_enable)
                                 asoc->peer.asconf_capable = 1;
                         break;
+                case SCTP_CID_I_DATA:
+                        if (sctp_sk(asoc->base.sk)->strm_interleave)
+                                asoc->intl_enable = 1;
+                        break;
                 default:
                         break;
                 }