net: sctp: implement rfc6458, 5.3.6. SCTP_NXTINFO cmsg support
This patch implements section 5.3.6. of RFC6458, that is, support
for 'SCTP Next Receive Information Structure' (SCTP_NXTINFO) which
is placed into ancillary data cmsghdr structure for each recvmsg()
call, if this information is already available when delivering the
current message.
This option can be enabled/disabled via setsockopt(2) on SOL_SCTP
level by setting an int value with 1/0 for SCTP_RECVNXTINFO in
user space applications as per RFC6458, section 8.1.30.
The sctp_nxtinfo structure is defined as per RFC as below ...
struct sctp_nxtinfo {
uint16_t nxt_sid;
uint16_t nxt_flags;
uint32_t nxt_ppid;
uint32_t nxt_length;
sctp_assoc_t nxt_assoc_id;
};
... and provided under cmsg_level IPPROTO_SCTP, cmsg_type
SCTP_NXTINFO, while cmsg_data[] contains struct sctp_nxtinfo.
Joint work with Daniel Borkmann.
Signed-off-by: Geir Ola Vaagland <geirola@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 29b81bb..222f82f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -96,6 +96,7 @@
#define SCTP_AUTO_ASCONF 30
#define SCTP_PEER_ADDR_THLDS 31
#define SCTP_RECVRCVINFO 32
+#define SCTP_RECVNXTINFO 33
/* Internal Socket Options. Some of the sctp library functions are
* implemented using these socket options.
@@ -111,6 +112,13 @@
#define SCTP_SOCKOPT_CONNECTX3 111 /* CONNECTX requests (updated) */
#define SCTP_GET_ASSOC_STATS 112 /* Read only */
+/* These are bit fields for msghdr->msg_flags. See section 5.1. */
+/* On user space Linux, these live in <bits/socket.h> as an enum. */
+enum sctp_msg_flags {
+ MSG_NOTIFICATION = 0x8000,
+#define MSG_NOTIFICATION MSG_NOTIFICATION
+};
+
/* 5.3.1 SCTP Initiation Structure (SCTP_INIT)
*
* This cmsghdr structure provides information for initializing new
@@ -187,6 +195,25 @@
sctp_assoc_t rcv_assoc_id;
};
+/* 5.3.6 SCTP Next Receive Information Structure (SCTP_NXTINFO)
+ *
+ * This cmsghdr structure describes SCTP receive information
+ * of the next message that will be delivered through recvmsg()
+ * if this information is already available when delivering
+ * the current message.
+ *
+ * cmsg_level cmsg_type cmsg_data[]
+ * ------------ ------------ -------------------
+ * IPPROTO_SCTP SCTP_NXTINFO struct sctp_nxtinfo
+ */
+struct sctp_nxtinfo {
+ __u16 nxt_sid;
+ __u16 nxt_flags;
+ __u32 nxt_ppid;
+ __u32 nxt_length;
+ sctp_assoc_t nxt_assoc_id;
+};
+
/*
* sinfo_flags: 16 bits (unsigned integer)
*
@@ -194,11 +221,12 @@
* 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. */
- SCTP_ABORT=4, /* Send an ABORT message to the peer. */
- SCTP_SACK_IMMEDIATELY = 8, /* SACK should be sent without delay */
- SCTP_EOF=MSG_FIN, /* Initiate graceful shutdown process. */
+ SCTP_UNORDERED = (1 << 0), /* Send/receive message unordered. */
+ SCTP_ADDR_OVER = (1 << 1), /* Override the primary destination. */
+ SCTP_ABORT = (1 << 2), /* Send an ABORT message to the peer. */
+ SCTP_SACK_IMMEDIATELY = (1 << 3), /* SACK should be sent without delay. */
+ SCTP_NOTIFICATION = MSG_NOTIFICATION, /* Next message is not user msg but notification. */
+ SCTP_EOF = MSG_FIN, /* Initiate graceful shutdown process. */
};
typedef union {
@@ -217,6 +245,8 @@
#define SCTP_SNDINFO SCTP_SNDINFO
SCTP_RCVINFO, /* 5.3.5 SCTP Receive Information Structure */
#define SCTP_RCVINFO SCTP_RCVINFO
+ SCTP_NXTINFO, /* 5.3.6 SCTP Next Receive Information Structure */
+#define SCTP_NXTINFO SCTP_NXTINFO
} sctp_cmsg_t;
/*
@@ -844,13 +874,6 @@
__u64 sas_ictrlchunks; /* Control chunks received */
};
-/* These are bit fields for msghdr->msg_flags. See section 5.1. */
-/* On user space Linux, these live in <bits/socket.h> as an enum. */
-enum sctp_msg_flags {
- MSG_NOTIFICATION = 0x8000,
-#define MSG_NOTIFICATION MSG_NOTIFICATION
-};
-
/*
* 8.1 sctp_bindx()
*