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/net/sctp/sctp.h b/include/net/sctp/sctp.h
index c2035c9..90c1ccc 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -109,6 +109,7 @@
struct sctp_association *asoc);
extern struct percpu_counter sctp_sockets_allocated;
int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
+struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
/*
* sctp/primitive.c
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 11d5df0..7741d1b 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -218,6 +218,7 @@
__u32 adaptation_ind;
__u32 pd_point;
__u8 recvrcvinfo;
+ __u8 recvnxtinfo;
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 e8095f9..cccdcfd 100644
--- a/include/net/sctp/ulpevent.h
+++ b/include/net/sctp/ulpevent.h
@@ -132,6 +132,8 @@
struct msghdr *);
void sctp_ulpevent_read_rcvinfo(const struct sctp_ulpevent *event,
struct msghdr *);
+void sctp_ulpevent_read_nxtinfo(const struct sctp_ulpevent *event,
+ struct msghdr *, struct sock *sk);
__u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event);
@@ -158,10 +160,3 @@
}
#endif /* __sctp_ulpevent_h__ */
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