[PATCHv5 net-next 5/5] sctp: implement sender-side procedures for Add Incoming/Outgoing Streams Request Parameter

[Xin Long]

This patch is to implement Sender-Side Procedures for the Add
Outgoing and Incoming Streams Request Parameter described in
rfc6525 section 5.1.5-5.1.6.

It is also to add sockopt SCTP_ADD_STREAMS in rfc6525 section
6.3.4 for users.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/net/sctp/sctp.h   |  2 ++
 include/uapi/linux/sctp.h |  7 ++++
 net/sctp/socket.c         | 29 +++++++++++++++++
 net/sctp/stream.c         | 81 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 119 insertions(+)

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index b93820f..68ee1a6 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -199,6 +199,8 @@ int sctp_offload_init(void);
 int sctp_send_reset_streams(struct sctp_association *asoc,
                            struct sctp_reset_streams *params);
 int sctp_send_reset_assoc(struct sctp_association *asoc);
+int sctp_send_add_streams(struct sctp_association *asoc,
+                         struct sctp_add_streams *params);
 
 /*
  * Module global variables
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index c0bd8c3..a91a9cc 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -118,6 +118,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_ENABLE_STREAM_RESET       118
 #define SCTP_RESET_STREAMS     119
 #define SCTP_RESET_ASSOC       120
+#define SCTP_ADD_STREAMS       121
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE      0x0000
@@ -1027,4 +1028,10 @@ struct sctp_reset_streams {
        uint16_t srs_stream_list[];     /* list if srs_num_streams is not 0 */
 };
 
+struct sctp_add_streams {
+       sctp_assoc_t sas_assoc_id;
+       uint16_t sas_instrms;
+       uint16_t sas_outstrms;
+};
+
 #endif /* _UAPI_SCTP_H */
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 2c5c9ca..ae0a99e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3838,6 +3838,32 @@ static int sctp_setsockopt_reset_assoc(struct sock *sk,
        return retval;
 }
 
+static int sctp_setsockopt_add_streams(struct sock *sk,
+                                      char __user *optval,
+                                      unsigned int optlen)
+{
+       struct sctp_association *asoc;
+       struct sctp_add_streams params;
+       int retval = -EINVAL;
+
+       if (optlen != sizeof(params))
+               goto out;
+
+       if (copy_from_user(&params, optval, optlen)) {
+               retval = -EFAULT;
+               goto out;
+       }
+
+       asoc = sctp_id2assoc(sk, params.sas_assoc_id);
+       if (!asoc)
+               goto out;
+
+       retval = sctp_send_add_streams(asoc, &params);
+
+out:
+       return retval;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4013,6 +4039,9 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        case SCTP_RESET_ASSOC:
                retval = sctp_setsockopt_reset_assoc(sk, optval, optlen);
                break;
+       case SCTP_ADD_STREAMS:
+               retval = sctp_setsockopt_add_streams(sk, optval, optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 53e49fc..7d467f0 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -217,3 +217,84 @@ int sctp_send_reset_assoc(struct sctp_association *asoc)
 
        return 0;
 }
+
+int sctp_send_add_streams(struct sctp_association *asoc,
+                         struct sctp_add_streams *params)
+{
+       struct sctp_stream *stream = asoc->stream;
+       struct sctp_chunk *chunk = NULL;
+       int retval = -ENOMEM;
+       __u16 out, in, nums;
+
+       if (!asoc->peer.reconf_capable ||
+           !(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
+               retval = -ENOPROTOOPT;
+               goto out;
+       }
+
+       if (asoc->strreset_outstanding) {
+               retval = -EINPROGRESS;
+               goto out;
+       }
+
+       out = params->sas_outstrms;
+       in  = params->sas_instrms;
+       if (stream->outcnt + out > SCTP_MAX_STREAM ||
+           stream->incnt + in > SCTP_MAX_STREAM || (!out && !in)) {
+               retval = -EINVAL;
+               goto out;
+       }
+
+       nums = stream->outcnt + out;
+       /* Use ksize to check if stream array really needs to realloc */
+       if (out && ksize(stream->out) < nums * sizeof(*stream->out)) {
+               struct sctp_stream_out *streamout;
+
+               streamout = kcalloc(nums, sizeof(*streamout), GFP_KERNEL);
+               if (!streamout)
+                       goto out;
+
+               memcpy(streamout, stream->out,
+                      sizeof(*streamout) * stream->outcnt);
+
+               kfree(stream->out);
+               stream->out = streamout;
+       }
+
+       nums = stream->incnt + in;
+       if (in && ksize(stream->in) < nums * sizeof(*stream->in)) {
+               struct sctp_stream_in *streamin;
+
+               streamin = kcalloc(nums, sizeof(*streamin), GFP_KERNEL);
+               if (!streamin)
+                       goto out;
+
+               memcpy(streamin, stream->in,
+                      sizeof(*streamin) * stream->incnt);
+
+               kfree(stream->in);
+               stream->in = streamin;
+       }
+
+       chunk = sctp_make_strreset_addstrm(asoc, out, in);
+       if (!chunk)
+               goto out;
+
+       asoc->strreset_chunk = chunk;
+       sctp_chunk_hold(asoc->strreset_chunk);
+
+       retval = sctp_send_reconf(asoc, chunk);
+       if (retval) {
+               sctp_chunk_put(asoc->strreset_chunk);
+               asoc->strreset_chunk = NULL;
+               goto out;
+       }
+
+       stream->incnt += in;
+       stream->outcnt += out;
+
+       asoc->strreset_outstanding = !!out + !!in;
+
+out:
+       return retval;
+}
-- 
2.1.0