diff mbox

[net-next,3/5] net: sctp: implement rfc6458, 5.3.5. SCTP_RCVINFO cmsg support

Message ID 1404507908-6949-4-git-send-email-dborkman@redhat.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Daniel Borkmann July 4, 2014, 9:05 p.m. UTC 
From: Geir Ola Vaagland <geirola@gmail.com>

This patch implements section 5.3.5. of RFC6458, that is, support
for 'SCTP Receive Information Structure' (SCTP_RCVINFO) which is
placed into ancillary data cmsghdr structure for each recvmsg()
call.

This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
level by setting an int value with 1/0 for SCTP_RECVRCVINFO in user
space applications as per RFC6458, section 8.1.29.

The sctp_rcvinfo structure is defined as per RFC as below ...

  struct sctp_rcvinfo {
    uint16_t rcv_sid;
    uint16_t rcv_ssn;
    uint16_t rcv_flags;
    <-- 2 bytes hole  -->
    uint32_t rcv_ppid;
    uint32_t rcv_tsn;
    uint32_t rcv_cumtsn;
    uint32_t rcv_context;
    sctp_assoc_t rcv_assoc_id;
  };

... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_RCVINFO, while cmsg_data[] contains struct sctp_rcvinfo.
An sctp_rcvinfo item always corresponds to the data in msg_iov.

Joint work with Daniel Borkmann.

Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
---
 include/net/sctp/structs.h  |  3 +++
 include/net/sctp/ulpevent.h |  5 ++++-
 include/uapi/linux/sctp.h   | 32 ++++++++++++++++++++++-------
 net/sctp/socket.c           | 49 ++++++++++++++++++++++++++++++++++++++++++++-
 net/sctp/ulpevent.c         | 25 +++++++++++++++++++++++
 5 files changed, 105 insertions(+), 9 deletions(-)

Comments

David Laight July 7, 2014, 8:54 a.m. UTC | #1 
From: Daniel Borkmann
> From: Geir Ola Vaagland <geirola@gmail.com>
> 
> This patch implements section 5.3.5. of RFC6458, that is, support
> for 'SCTP Receive Information Structure' (SCTP_RCVINFO) which is
> placed into ancillary data cmsghdr structure for each recvmsg()
> call.
> 
> This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
> level by setting an int value with 1/0 for SCTP_RECVRCVINFO in user
> space applications as per RFC6458, section 8.1.29.
> 
> The sctp_rcvinfo structure is defined as per RFC as below ...
> 
>   struct sctp_rcvinfo {
>     uint16_t rcv_sid;
>     uint16_t rcv_ssn;
>     uint16_t rcv_flags;
>     <-- 2 bytes hole  -->
>     uint32_t rcv_ppid;
>     uint32_t rcv_tsn;
>     uint32_t rcv_cumtsn;
>     uint32_t rcv_context;
>     sctp_assoc_t rcv_assoc_id;
>   };
> 
> ... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
> SCTP_RCVINFO, while cmsg_data[] contains struct sctp_rcvinfo.
> An sctp_rcvinfo item always corresponds to the data in msg_iov.
> 
> Joint work with Daniel Borkmann.
...
> +/* RFC6458, Section 5.3.5 SCTP Receive Information Structure
> + * (SCTP_SNDRCV)
> + */
> +void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
> +				struct msghdr *msghdr)
> +{
> +	struct sctp_rcvinfo rinfo;
> +
> +	if (sctp_ulpevent_is_notification(event))
> +		return;
> +
> +	memset(&rinfo, 0, sizeof(struct sctp_rcvinfo));
> +	rinfo.rcv_sid = event->stream;
> +	rinfo.rcv_ssn = event->ssn;
> +	rinfo.rcv_ppid = event->ppid;
> +	rinfo.rcv_flags = event->flags;
> +	rinfo.rcv_tsn = event->tsn;
> +	rinfo.rcv_cumtsn = event->cumtsn;
> +	rinfo.rcv_assoc_id = sctp_assoc2id(event->asoc);
> +	rinfo.rcv_context = event->asoc->default_rcv_context;
> +
> +	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_RCVINFO,
> +		 sizeof(rinfo), &rinfo);
> +}

This gets called for every receive data chunk (since the user needs to
verify the ssn and stream).

It really ought to be possible to write the 'cmsg' data with quite so
many memory accesses.

Perhaps you should add named fields for the pads so they can be explicitly zeroed.

It also seems that put_cmsg() should be able to return the pointer to
where the data should be written - instead on copying the data itself.

	David



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David Laight July 7, 2014, 8:56 a.m. UTC | #2 
From: David Laight
...
> > +	memset(&rinfo, 0, sizeof(struct sctp_rcvinfo));
> > +	rinfo.rcv_sid = event->stream;
> > +	rinfo.rcv_ssn = event->ssn;
> > +	rinfo.rcv_ppid = event->ppid;
> > +	rinfo.rcv_flags = event->flags;
> > +	rinfo.rcv_tsn = event->tsn;
> > +	rinfo.rcv_cumtsn = event->cumtsn;
> > +	rinfo.rcv_assoc_id = sctp_assoc2id(event->asoc);
> > +	rinfo.rcv_context = event->asoc->default_rcv_context;
> > +
> > +	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_RCVINFO,
> > +		 sizeof(rinfo), &rinfo);
> > +}
> 
> This gets called for every receive data chunk (since the user needs to
> verify the ssn and stream).

Clearly I meant ppid and stream :-(

	David



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Daniel Borkmann July 8, 2014, 8:51 a.m. UTC | #3 
On 07/07/2014 10:54 AM, David Laight wrote:
> From: Daniel Borkmann
>> From: Geir Ola Vaagland <geirola@gmail.com>
>>
>> This patch implements section 5.3.5. of RFC6458, that is, support
>> for 'SCTP Receive Information Structure' (SCTP_RCVINFO) which is
>> placed into ancillary data cmsghdr structure for each recvmsg()
>> call.
>>
>> This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
>> level by setting an int value with 1/0 for SCTP_RECVRCVINFO in user
>> space applications as per RFC6458, section 8.1.29.
>>
>> The sctp_rcvinfo structure is defined as per RFC as below ...
>>
>>    struct sctp_rcvinfo {
>>      uint16_t rcv_sid;
>>      uint16_t rcv_ssn;
>>      uint16_t rcv_flags;
>>      <-- 2 bytes hole  -->
>>      uint32_t rcv_ppid;
>>      uint32_t rcv_tsn;
>>      uint32_t rcv_cumtsn;
>>      uint32_t rcv_context;
>>      sctp_assoc_t rcv_assoc_id;
>>    };
>>
>> ... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
>> SCTP_RCVINFO, while cmsg_data[] contains struct sctp_rcvinfo.
>> An sctp_rcvinfo item always corresponds to the data in msg_iov.
>>
>> Joint work with Daniel Borkmann.
> ...
>> +/* RFC6458, Section 5.3.5 SCTP Receive Information Structure
>> + * (SCTP_SNDRCV)
>> + */
>> +void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
>> +				struct msghdr *msghdr)
>> +{
>> +	struct sctp_rcvinfo rinfo;
>> +
>> +	if (sctp_ulpevent_is_notification(event))
>> +		return;
>> +
>> +	memset(&rinfo, 0, sizeof(struct sctp_rcvinfo));
>> +	rinfo.rcv_sid = event->stream;
>> +	rinfo.rcv_ssn = event->ssn;
>> +	rinfo.rcv_ppid = event->ppid;
>> +	rinfo.rcv_flags = event->flags;
>> +	rinfo.rcv_tsn = event->tsn;
>> +	rinfo.rcv_cumtsn = event->cumtsn;
>> +	rinfo.rcv_assoc_id = sctp_assoc2id(event->asoc);
>> +	rinfo.rcv_context = event->asoc->default_rcv_context;
>> +
>> +	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_RCVINFO,
>> +		 sizeof(rinfo), &rinfo);
>> +}

Sorry for the late answer, as I'm on travel this week.

> This gets called for every receive data chunk (since the user needs to
> verify the ssn and stream).
>
> It really ought to be possible to write the 'cmsg' data with quite so
> many memory accesses.
>
> Perhaps you should add named fields for the pads so they can be explicitly zeroed.

I really dislike the idea to put padding members into a uapi struct, we
should stick to the RFC though it specified it with holes in the struct.
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diff mbox

Patch

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7af9a0f..11d5df0 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -207,7 +207,9 @@  struct sctp_sock {
 	struct sctp_paddrparams paddrparam;
 	struct sctp_event_subscribe subscribe;
 	struct sctp_assocparams assocparams;
+
 	int user_frag;
+
 	__u32 autoclose;
 	__u8 nodelay;
 	__u8 disable_fragments;
@@ -215,6 +217,7 @@  struct sctp_sock {
 	__u8 frag_interleave;
 	__u32 adaptation_ind;
 	__u32 pd_point;
+	__u8 recvrcvinfo;
 
 	atomic_t pd_mode;
 	/* Receive to here while partial delivery is in effect. */
diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h
index daacb32..e8095f9 100644
--- a/include/net/sctp/ulpevent.h
+++ b/include/net/sctp/ulpevent.h
@@ -129,7 +129,10 @@  struct sctp_ulpevent *sctp_ulpevent_make_sender_dry_event(
 	const struct sctp_association *asoc, gfp_t gfp);
 
 void sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent *event,
-	struct msghdr *);
+				   struct msghdr *);
+void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
+				struct msghdr *);
+
 __u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event);
 
 /* Is this event type enabled? */
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index a387761..29b81bb 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -95,6 +95,7 @@  typedef __s32 sctp_assoc_t;
 #define SCTP_GET_ASSOC_ID_LIST	29	/* Read only */
 #define SCTP_AUTO_ASCONF       30
 #define SCTP_PEER_ADDR_THLDS	31
+#define SCTP_RECVRCVINFO	32
 
 /* Internal Socket Options. Some of the sctp library functions are
  * implemented using these socket options.
@@ -110,8 +111,7 @@  typedef __s32 sctp_assoc_t;
 #define SCTP_SOCKOPT_CONNECTX3	111	/* CONNECTX requests (updated) */
 #define SCTP_GET_ASSOC_STATS	112	/* Read only */
 
-/*
- * 5.2.1 SCTP Initiation Structure (SCTP_INIT)
+/* 5.3.1 SCTP Initiation Structure (SCTP_INIT)
  *
  *   This cmsghdr structure provides information for initializing new
  *   SCTP associations with sendmsg().  The SCTP_INITMSG socket option
@@ -121,7 +121,6 @@  typedef __s32 sctp_assoc_t;
  *   cmsg_level    cmsg_type      cmsg_data[]
  *   ------------  ------------   ----------------------
  *   IPPROTO_SCTP  SCTP_INIT      struct sctp_initmsg
- *
  */
 struct sctp_initmsg {
 	__u16 sinit_num_ostreams;
@@ -130,8 +129,7 @@  struct sctp_initmsg {
 	__u16 sinit_max_init_timeo;
 };
 
-/*
- * 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
+/* 5.3.2 SCTP Header Information Structure (SCTP_SNDRCV)
  *
  *   This cmsghdr structure specifies SCTP options for sendmsg() and
  *   describes SCTP header information about a received message through
@@ -140,7 +138,6 @@  struct sctp_initmsg {
  *   cmsg_level    cmsg_type      cmsg_data[]
  *   ------------  ------------   ----------------------
  *   IPPROTO_SCTP  SCTP_SNDRCV    struct sctp_sndrcvinfo
- *
  */
 struct sctp_sndrcvinfo {
 	__u16 sinfo_stream;
@@ -170,13 +167,32 @@  struct sctp_sndinfo {
 	sctp_assoc_t snd_assoc_id;
 };
 
+/* 5.3.5 SCTP Receive Information Structure (SCTP_RCVINFO)
+ *
+ *   This cmsghdr structure describes SCTP receive information
+ *   about a received message through recvmsg().
+ *
+ *   cmsg_level    cmsg_type      cmsg_data[]
+ *   ------------  ------------   -------------------
+ *   IPPROTO_SCTP  SCTP_RCVINFO   struct sctp_rcvinfo
+ */
+struct sctp_rcvinfo {
+	__u16 rcv_sid;
+	__u16 rcv_ssn;
+	__u16 rcv_flags;
+	__u32 rcv_ppid;
+	__u32 rcv_tsn;
+	__u32 rcv_cumtsn;
+	__u32 rcv_context;
+	sctp_assoc_t rcv_assoc_id;
+};
+
 /*
  *  sinfo_flags: 16 bits (unsigned integer)
  *
  *   This field may contain any of the following flags and is composed of
  *   a bitwise OR of these values.
  */
-
 enum sctp_sinfo_flags {
 	SCTP_UNORDERED = 1,  /* Send/receive message unordered. */
 	SCTP_ADDR_OVER = 2,  /* Override the primary destination. */
@@ -199,6 +215,8 @@  typedef enum sctp_cmsg_type {
 #define SCTP_SNDRCV	SCTP_SNDRCV
 	SCTP_SNDINFO,		/* 5.3.4 SCTP Send Information Structure */
 #define SCTP_SNDINFO	SCTP_SNDINFO
+	SCTP_RCVINFO,		/* 5.3.5 SCTP Receive Information Structure */
+#define SCTP_RCVINFO	SCTP_RCVINFO
 } sctp_cmsg_t;
 
 /*
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index d61729e..9c19388 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2112,9 +2112,13 @@  static int sctp_recvmsg(struct kiocb *iocb, struct sock *sk,
 		sp->pf->skb_msgname(skb, msg->msg_name, addr_len);
 	}
 
+	/* Check if we allow SCTP_RCVINFO. */
+	if (sp->recvrcvinfo)
+		sctp_ulpevent_read_rcvinfo(event, msg);
 	/* Check if we allow SCTP_SNDRCVINFO. */
 	if (sp->subscribe.sctp_data_io_event)
 		sctp_ulpevent_read_sndrcvinfo(event, msg);
+
 #if 0
 	/* FIXME: we should be calling IP/IPv6 layers.  */
 	if (sk->sk_protinfo.af_inet.cmsg_flags)
@@ -3541,7 +3545,6 @@  static int sctp_setsockopt_auto_asconf(struct sock *sk, char __user *optval,
 	return 0;
 }
 
-
 /*
  * SCTP_PEER_ADDR_THLDS
  *
@@ -3592,6 +3595,22 @@  static int sctp_setsockopt_paddr_thresholds(struct sock *sk,
 	return 0;
 }
 
+static int sctp_setsockopt_recvrcvinfo(struct sock *sk,
+				       char __user *optval,
+				       unsigned int optlen)
+{
+	int val;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+	if (get_user(val, (int __user *) optval))
+		return -EFAULT;
+
+	sctp_sk(sk)->recvrcvinfo = (val == 0) ? 0 : 1;
+
+	return 0;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -3743,6 +3762,9 @@  static int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_PEER_ADDR_THLDS:
 		retval = sctp_setsockopt_paddr_thresholds(sk, optval, optlen);
 		break;
+	case SCTP_RECVRCVINFO:
+		retval = sctp_setsockopt_recvrcvinfo(sk, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
@@ -3989,6 +4011,8 @@  static int sctp_init_sock(struct sock *sk)
 	/* Enable Nagle algorithm by default.  */
 	sp->nodelay           = 0;
 
+	sp->recvrcvinfo = 0;
+
 	/* Enable by default. */
 	sp->v4mapped          = 1;
 
@@ -5770,6 +5794,26 @@  static int sctp_getsockopt_assoc_stats(struct sock *sk, int len,
 	return 0;
 }
 
+static int sctp_getsockopt_recvrcvinfo(struct sock *sk,	int len,
+				       char __user *optval,
+				       int __user *optlen)
+{
+	int val = 0;
+
+	if (len < sizeof(int))
+		return -EINVAL;
+
+	len = sizeof(int);
+	if (sctp_sk(sk)->recvrcvinfo)
+		val = 1;
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
 			   char __user *optval, int __user *optlen)
 {
@@ -5913,6 +5957,9 @@  static int sctp_getsockopt(struct sock *sk, int level, int optname,
 	case SCTP_GET_ASSOC_STATS:
 		retval = sctp_getsockopt_assoc_stats(sk, len, optval, optlen);
 		break;
+	case SCTP_RECVRCVINFO:
+		retval = sctp_getsockopt_recvrcvinfo(sk, len, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index b6842fd..b31f365 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -886,6 +886,31 @@  void sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent *event,
 		 sizeof(sinfo), &sinfo);
 }
 
+/* RFC6458, Section 5.3.5 SCTP Receive Information Structure
+ * (SCTP_SNDRCV)
+ */
+void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
+				struct msghdr *msghdr)
+{
+	struct sctp_rcvinfo rinfo;
+
+	if (sctp_ulpevent_is_notification(event))
+		return;
+
+	memset(&rinfo, 0, sizeof(struct sctp_rcvinfo));
+	rinfo.rcv_sid = event->stream;
+	rinfo.rcv_ssn = event->ssn;
+	rinfo.rcv_ppid = event->ppid;
+	rinfo.rcv_flags = event->flags;
+	rinfo.rcv_tsn = event->tsn;
+	rinfo.rcv_cumtsn = event->cumtsn;
+	rinfo.rcv_assoc_id = sctp_assoc2id(event->asoc);
+	rinfo.rcv_context = event->asoc->default_rcv_context;
+
+	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_RCVINFO,
+		 sizeof(rinfo), &rinfo);
+}
+
 /* Do accounting for bytes received and hold a reference to the association
  * for each skb.
  */