From 965ae44412f8c0c19945b3f62bc945ad0b15a8aa Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:04:58 +0800
Subject: sctp: create udp4 sock and add its encap_rcv

This patch is to add the functions to create/release udp4 sock,
and set the sock's encap_rcv to process the incoming udp encap
sctp packets. In sctp_udp_rcv(), as we can see, all we need to
do is fix the transport header for sctp_rcv(), then it would
implement the part of rfc6951#section-5.4:

  "When an encapsulated packet is received, the UDP header is removed.
   Then, the generic lookup is performed, as done by an SCTP stack
   whenever a packet is received, to find the association for the
   received SCTP packet"

Note that these functions will be called in the last patch of
this patchset when enabling this feature.

v1->v2:
  - Add pr_err() when fails to create udp v4 sock.
v2->v3:
  - Add 'select NET_UDP_TUNNEL' in sctp Kconfig.
v3->v4:
  - No change.
v4->v5:
  - Change to set udp_port to 0 by default.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/netns/sctp.h     | 5 +++++
 include/net/sctp/constants.h | 2 ++
 include/net/sctp/sctp.h      | 2 ++
 3 files changed, 9 insertions(+)

(limited to 'include')

diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h
index d8d02e4188d1..8cc9aff24329 100644
--- a/include/net/netns/sctp.h
+++ b/include/net/netns/sctp.h
@@ -22,6 +22,11 @@ struct netns_sctp {
 	 */
 	struct sock *ctl_sock;
 
+	/* UDP tunneling listening sock. */
+	struct sock *udp4_sock;
+	/* UDP tunneling listening port. */
+	int udp_port;
+
 	/* This is the global local address list.
 	 * We actively maintain this complete list of addresses on
 	 * the system by catching address add/delete events.
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 122d9e2d8dfd..14a0d22c9113 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -286,6 +286,8 @@ enum { SCTP_MAX_GABS = 16 };
 				 * functions simpler to write.
 				 */
 
+#define SCTP_DEFAULT_UDP_PORT 9899	/* default UDP tunneling port */
+
 /* These are the values for pf exposure, UNUSED is to keep compatible with old
  * applications by default.
  */
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 4fc747b778eb..bfd87a0aa2f1 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -84,6 +84,8 @@ int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
 int sctp_register_pf(struct sctp_pf *, sa_family_t);
 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
+int sctp_udp_sock_start(struct net *net);
+void sctp_udp_sock_stop(struct net *net);
 
 /*
  * sctp/socket.c
-- 
cgit v1.2.3


From 9d6ba260a0734d5e56243929a69d57ebbf0cb245 Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:04:59 +0800
Subject: sctp: create udp6 sock and set its encap_rcv

This patch is to add the udp6 sock part in sctp_udp_sock_start/stop().
udp_conf.use_udp6_rx_checksums is set to true, as:

   "The SCTP checksum MUST be computed for IPv4 and IPv6, and the UDP
    checksum SHOULD be computed for IPv4 and IPv6"

says in rfc6951#section-5.3.

v1->v2:
  - Add pr_err() when fails to create udp v6 sock.
  - Add #if IS_ENABLED(CONFIG_IPV6) not to create v6 sock when ipv6 is
    disabled.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/netns/sctp.h |  1 +
 net/sctp/protocol.c      | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

(limited to 'include')

diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h
index 8cc9aff24329..247b401a0f52 100644
--- a/include/net/netns/sctp.h
+++ b/include/net/netns/sctp.h
@@ -24,6 +24,7 @@ struct netns_sctp {
 
 	/* UDP tunneling listening sock. */
 	struct sock *udp4_sock;
+	struct sock *udp6_sock;
 	/* UDP tunneling listening port. */
 	int udp_port;
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 0f7933422d8e..8410c9a3f145 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -869,6 +869,28 @@ int sctp_udp_sock_start(struct net *net)
 	setup_udp_tunnel_sock(net, sock, &tuncfg);
 	net->sctp.udp4_sock = sock->sk;
 
+#if IS_ENABLED(CONFIG_IPV6)
+	memset(&udp_conf, 0, sizeof(udp_conf));
+
+	udp_conf.family = AF_INET6;
+	udp_conf.local_ip6 = in6addr_any;
+	udp_conf.local_udp_port = htons(net->sctp.udp_port);
+	udp_conf.use_udp6_rx_checksums = true;
+	udp_conf.ipv6_v6only = true;
+	err = udp_sock_create(net, &udp_conf, &sock);
+	if (err) {
+		pr_err("Failed to create the SCTP UDP tunneling v6 sock\n");
+		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
+		net->sctp.udp4_sock = NULL;
+		return err;
+	}
+
+	tuncfg.encap_type = 1;
+	tuncfg.encap_rcv = sctp_udp_rcv;
+	setup_udp_tunnel_sock(net, sock, &tuncfg);
+	net->sctp.udp6_sock = sock->sk;
+#endif
+
 	return 0;
 }
 
@@ -878,6 +900,10 @@ void sctp_udp_sock_stop(struct net *net)
 		udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
 		net->sctp.udp4_sock = NULL;
 	}
+	if (net->sctp.udp6_sock) {
+		udp_tunnel_sock_release(net->sctp.udp6_sock->sk_socket);
+		net->sctp.udp6_sock = NULL;
+	}
 }
 
 /* Register address family specific functions. */
-- 
cgit v1.2.3


From e8a3001c2120c760017da81a307308572a3cdbbc Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:05:01 +0800
Subject: sctp: add encap_port for netns sock asoc and transport

encap_port is added as per netns/sock/assoc/transport, and the
latter one's encap_port inherits the former one's by default.
The transport's encap_port value would mostly decide if one
packet should go out with udp encapsulated or not.

This patch also allows users to set netns' encap_port by sysctl.

v1->v2:
  - Change to define encap_port as __be16 for sctp_sock, asoc and
    transport.
v2->v3:
  - No change.
v3->v4:
  - Add 'encap_port' entry in ip-sysctl.rst.
v4->v5:
  - Improve the description of encap_port in ip-sysctl.rst.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 Documentation/networking/ip-sysctl.rst | 16 ++++++++++++++++
 include/net/netns/sctp.h               |  2 ++
 include/net/sctp/structs.h             |  6 ++++++
 net/sctp/associola.c                   |  4 ++++
 net/sctp/protocol.c                    |  3 +++
 net/sctp/socket.c                      |  1 +
 net/sctp/sysctl.c                      | 10 ++++++++++
 7 files changed, 42 insertions(+)

(limited to 'include')

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 25e6673a085a..dad3ba952989 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2642,6 +2642,22 @@ addr_scope_policy - INTEGER
 
 	Default: 1
 
+encap_port - INTEGER
+	The default remote UDP encapsulation port.
+
+	This value is used to set the dest port of the UDP header for the
+	outgoing UDP-encapsulated SCTP packets by default. Users can also
+	change the value for each sock/asoc/transport by using setsockopt.
+	For further information, please refer to RFC6951.
+
+	Note that when connecting to a remote server, the client should set
+	this to the port that the UDP tunneling sock on the peer server is
+	listening to and the local UDP tunneling sock on the client also
+	must be started. On the server, it would get the encap_port from
+	the incoming packet's source port.
+
+	Default: 0
+
 
 ``/proc/sys/net/core/*``
 ========================
diff --git a/include/net/netns/sctp.h b/include/net/netns/sctp.h
index 247b401a0f52..a0f315effa94 100644
--- a/include/net/netns/sctp.h
+++ b/include/net/netns/sctp.h
@@ -27,6 +27,8 @@ struct netns_sctp {
 	struct sock *udp6_sock;
 	/* UDP tunneling listening port. */
 	int udp_port;
+	/* UDP tunneling remote encap port. */
+	int encap_port;
 
 	/* This is the global local address list.
 	 * We actively maintain this complete list of addresses on
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 0bdff38eb4bb..aa98e7e659ac 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -178,6 +178,8 @@ struct sctp_sock {
 	 */
 	__u32 hbinterval;
 
+	__be16 encap_port;
+
 	/* This is the max_retrans value for new associations. */
 	__u16 pathmaxrxt;
 
@@ -877,6 +879,8 @@ struct sctp_transport {
 	 */
 	unsigned long last_time_ecne_reduced;
 
+	__be16 encap_port;
+
 	/* This is the max_retrans value for the transport and will
 	 * be initialized from the assocs value.  This can be changed
 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
@@ -1790,6 +1794,8 @@ struct sctp_association {
 	 */
 	unsigned long hbinterval;
 
+	__be16 encap_port;
+
 	/* This is the max_retrans value for new transports in the
 	 * association.
 	 */
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index fdb69d46276d..336df4b36655 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -99,6 +99,8 @@ static struct sctp_association *sctp_association_init(
 	 */
 	asoc->hbinterval = msecs_to_jiffies(sp->hbinterval);
 
+	asoc->encap_port = sp->encap_port;
+
 	/* Initialize path max retrans value. */
 	asoc->pathmaxrxt = sp->pathmaxrxt;
 
@@ -624,6 +626,8 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 	 */
 	peer->hbinterval = asoc->hbinterval;
 
+	peer->encap_port = asoc->encap_port;
+
 	/* Set the path max_retrans.  */
 	peer->pathmaxrxt = asoc->pathmaxrxt;
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 4d12a0c869b8..89dfd313e113 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1359,6 +1359,9 @@ static int __net_init sctp_defaults_init(struct net *net)
 	/* Set UDP tunneling listening port to 0 by default */
 	net->sctp.udp_port = 0;
 
+	/* Set remote encap port to 0 by default */
+	net->sctp.encap_port = 0;
+
 	/* Set SCOPE policy to enabled */
 	net->sctp.scope_policy = SCTP_SCOPE_POLICY_ENABLE;
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 53d0a4161df3..09b94cd7ca37 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4876,6 +4876,7 @@ static int sctp_init_sock(struct sock *sk)
 	 * be modified via SCTP_PEER_ADDR_PARAMS
 	 */
 	sp->hbinterval  = net->sctp.hb_interval;
+	sp->encap_port  = htons(net->sctp.encap_port);
 	sp->pathmaxrxt  = net->sctp.max_retrans_path;
 	sp->pf_retrans  = net->sctp.pf_retrans;
 	sp->ps_retrans  = net->sctp.ps_retrans;
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index c16c80963e55..ecc1b5e4c297 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -36,6 +36,7 @@ static int rto_alpha_max = 1000;
 static int rto_beta_max = 1000;
 static int pf_expose_max = SCTP_PF_EXPOSE_MAX;
 static int ps_retrans_max = SCTP_PS_RETRANS_MAX;
+static int udp_port_max = 65535;
 
 static unsigned long max_autoclose_min = 0;
 static unsigned long max_autoclose_max =
@@ -290,6 +291,15 @@ static struct ctl_table sctp_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.procname	= "encap_port",
+		.data		= &init_net.sctp.encap_port,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= &udp_port_max,
+	},
 	{
 		.procname	= "addr_scope_policy",
 		.data		= &init_net.sctp.scope_policy,
-- 
cgit v1.2.3


From 8dba29603b5c8bfca2bf90aeb83d05a236df967b Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:05:02 +0800
Subject: sctp: add SCTP_REMOTE_UDP_ENCAPS_PORT sockopt

This patch is to implement:

  rfc6951#section-6.1: Get or Set the Remote UDP Encapsulation Port Number

with the param of the struct:

  struct sctp_udpencaps {
    sctp_assoc_t sue_assoc_id;
    struct sockaddr_storage sue_address;
    uint16_t sue_port;
  };

the encap_port of sock, assoc or transport can be changed by users,
which also means it allows the different transports of the same asoc
to have different encap_port value.

v1->v2:
  - no change.
v2->v3:
  - fix the endian warning when setting values between encap_port and
    sue_port.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/uapi/linux/sctp.h |   7 +++
 net/sctp/socket.c         | 114 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)

(limited to 'include')

diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 28ad40d9acba..cb78e7a739da 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -140,6 +140,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_ECN_SUPPORTED	130
 #define SCTP_EXPOSE_POTENTIALLY_FAILED_STATE	131
 #define SCTP_EXPOSE_PF_STATE	SCTP_EXPOSE_POTENTIALLY_FAILED_STATE
+#define SCTP_REMOTE_UDP_ENCAPS_PORT	132
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE	0x0000
@@ -1197,6 +1198,12 @@ struct sctp_event {
 	uint8_t se_on;
 };
 
+struct sctp_udpencaps {
+	sctp_assoc_t sue_assoc_id;
+	struct sockaddr_storage sue_address;
+	uint16_t sue_port;
+};
+
 /* SCTP Stream schedulers */
 enum sctp_sched_type {
 	SCTP_SS_FCFS,
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 09b94cd7ca37..2a9ee9b3e46c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4417,6 +4417,55 @@ out:
 	return retval;
 }
 
+static int sctp_setsockopt_encap_port(struct sock *sk,
+				      struct sctp_udpencaps *encap,
+				      unsigned int optlen)
+{
+	struct sctp_association *asoc;
+	struct sctp_transport *t;
+	__be16 encap_port;
+
+	if (optlen != sizeof(*encap))
+		return -EINVAL;
+
+	/* If an address other than INADDR_ANY is specified, and
+	 * no transport is found, then the request is invalid.
+	 */
+	encap_port = (__force __be16)encap->sue_port;
+	if (!sctp_is_any(sk, (union sctp_addr *)&encap->sue_address)) {
+		t = sctp_addr_id2transport(sk, &encap->sue_address,
+					   encap->sue_assoc_id);
+		if (!t)
+			return -EINVAL;
+
+		t->encap_port = encap_port;
+		return 0;
+	}
+
+	/* Get association, if assoc_id != SCTP_FUTURE_ASSOC and the
+	 * socket is a one to many style socket, and an association
+	 * was not found, then the id was invalid.
+	 */
+	asoc = sctp_id2assoc(sk, encap->sue_assoc_id);
+	if (!asoc && encap->sue_assoc_id != SCTP_FUTURE_ASSOC &&
+	    sctp_style(sk, UDP))
+		return -EINVAL;
+
+	/* If changes are for association, also apply encap_port to
+	 * each transport.
+	 */
+	if (asoc) {
+		list_for_each_entry(t, &asoc->peer.transport_addr_list,
+				    transports)
+			t->encap_port = encap_port;
+
+		return 0;
+	}
+
+	sctp_sk(sk)->encap_port = encap_port;
+	return 0;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4636,6 +4685,9 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_EXPOSE_POTENTIALLY_FAILED_STATE:
 		retval = sctp_setsockopt_pf_expose(sk, kopt, optlen);
 		break;
+	case SCTP_REMOTE_UDP_ENCAPS_PORT:
+		retval = sctp_setsockopt_encap_port(sk, kopt, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
@@ -7791,6 +7843,65 @@ out:
 	return retval;
 }
 
+static int sctp_getsockopt_encap_port(struct sock *sk, int len,
+				      char __user *optval, int __user *optlen)
+{
+	struct sctp_association *asoc;
+	struct sctp_udpencaps encap;
+	struct sctp_transport *t;
+	__be16 encap_port;
+
+	if (len < sizeof(encap))
+		return -EINVAL;
+
+	len = sizeof(encap);
+	if (copy_from_user(&encap, optval, len))
+		return -EFAULT;
+
+	/* If an address other than INADDR_ANY is specified, and
+	 * no transport is found, then the request is invalid.
+	 */
+	if (!sctp_is_any(sk, (union sctp_addr *)&encap.sue_address)) {
+		t = sctp_addr_id2transport(sk, &encap.sue_address,
+					   encap.sue_assoc_id);
+		if (!t) {
+			pr_debug("%s: failed no transport\n", __func__);
+			return -EINVAL;
+		}
+
+		encap_port = t->encap_port;
+		goto out;
+	}
+
+	/* Get association, if assoc_id != SCTP_FUTURE_ASSOC and the
+	 * socket is a one to many style socket, and an association
+	 * was not found, then the id was invalid.
+	 */
+	asoc = sctp_id2assoc(sk, encap.sue_assoc_id);
+	if (!asoc && encap.sue_assoc_id != SCTP_FUTURE_ASSOC &&
+	    sctp_style(sk, UDP)) {
+		pr_debug("%s: failed no association\n", __func__);
+		return -EINVAL;
+	}
+
+	if (asoc) {
+		encap_port = asoc->encap_port;
+		goto out;
+	}
+
+	encap_port = sctp_sk(sk)->encap_port;
+
+out:
+	encap.sue_port = (__force uint16_t)encap_port;
+	if (copy_to_user(optval, &encap, len))
+		return -EFAULT;
+
+	if (put_user(len, optlen))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
 			   char __user *optval, int __user *optlen)
 {
@@ -8011,6 +8122,9 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname,
 	case SCTP_EXPOSE_POTENTIALLY_FAILED_STATE:
 		retval = sctp_getsockopt_pf_expose(sk, len, optval, optlen);
 		break;
+	case SCTP_REMOTE_UDP_ENCAPS_PORT:
+		retval = sctp_getsockopt_encap_port(sk, len, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
-- 
cgit v1.2.3


From a1dd2cf2f1aedabc2ca9bb4f90231a521c52d8eb Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:05:03 +0800
Subject: sctp: allow changing transport encap_port by peer packets

As rfc6951#section-5.4 says:

  "After finding the SCTP association (which
   includes checking the verification tag), the UDP source port MUST be
   stored as the encapsulation port for the destination address the SCTP
   packet is received from (see Section 5.1).

   When a non-encapsulated SCTP packet is received by the SCTP stack,
   the encapsulation of outgoing packets belonging to the same
   association and the corresponding destination address MUST be
   disabled."

transport encap_port should be updated by a validated incoming packet's
udp src port.

We save the udp src port in sctp_input_cb->encap_port, and then update
the transport in two places:

  1. right after vtag is verified, which is required by RFC, and this
     allows the existent transports to be updated by the chunks that
     can only be processed on an asoc.

  2. right before processing the 'init' where the transports are added,
     and this allows building a sctp over udp connection by client with
     the server not knowing the remote encap port.

  3. when processing ootb_pkt and creating the temporary transport for
     the reply pkt.

Note that sctp_input_cb->header is removed, as it's not used any more
in sctp.

v1->v2:
  - Change encap_port as __be16 for sctp_input_cb.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/sctp/sm.h      |  1 +
 include/net/sctp/structs.h |  7 +------
 net/sctp/ipv6.c            |  1 +
 net/sctp/protocol.c        | 11 ++++++++++-
 net/sctp/sm_make_chunk.c   |  1 +
 net/sctp/sm_statefuns.c    |  2 ++
 6 files changed, 16 insertions(+), 7 deletions(-)

(limited to 'include')

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 5c491a3bc27e..a499341472ad 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -380,6 +380,7 @@ sctp_vtag_verify(const struct sctp_chunk *chunk,
         if (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)
                 return 1;
 
+	chunk->transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
 	return 0;
 }
 
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index aa98e7e659ac..81464ae2b137 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1120,14 +1120,9 @@ static inline void sctp_outq_cork(struct sctp_outq *q)
  * sctp_input_cb is currently used on rx and sock rx queue
  */
 struct sctp_input_cb {
-	union {
-		struct inet_skb_parm	h4;
-#if IS_ENABLED(CONFIG_IPV6)
-		struct inet6_skb_parm	h6;
-#endif
-	} header;
 	struct sctp_chunk *chunk;
 	struct sctp_af *af;
+	__be16 encap_port;
 };
 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
 
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 8a58f42d6d19..a064bf252b17 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -1053,6 +1053,7 @@ static struct inet_protosw sctpv6_stream_protosw = {
 
 static int sctp6_rcv(struct sk_buff *skb)
 {
+	memset(skb->cb, 0, sizeof(skb->cb));
 	return sctp_rcv(skb) ? -1 : 0;
 }
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 89dfd313e113..f3de8c03a15e 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -843,6 +843,9 @@ static int sctp_ctl_sock_init(struct net *net)
 
 static int sctp_udp_rcv(struct sock *sk, struct sk_buff *skb)
 {
+	memset(skb->cb, 0, sizeof(skb->cb));
+	SCTP_INPUT_CB(skb)->encap_port = udp_hdr(skb)->source;
+
 	skb_set_transport_header(skb, sizeof(struct udphdr));
 	sctp_rcv(skb);
 	return 0;
@@ -1139,9 +1142,15 @@ static struct inet_protosw sctp_stream_protosw = {
 	.flags      = SCTP_PROTOSW_FLAG
 };
 
+static int sctp4_rcv(struct sk_buff *skb)
+{
+	memset(skb->cb, 0, sizeof(skb->cb));
+	return sctp_rcv(skb);
+}
+
 /* Register with IP layer.  */
 static const struct net_protocol sctp_protocol = {
-	.handler     = sctp_rcv,
+	.handler     = sctp4_rcv,
 	.err_handler = sctp_v4_err,
 	.no_policy   = 1,
 	.netns_ok    = 1,
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 9a56ae2f3651..21d0ff1c6ab9 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2321,6 +2321,7 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
 	 * added as the primary transport.  The source address seems to
 	 * be a better choice than any of the embedded addresses.
 	 */
+	asoc->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
 	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
 		goto nomem;
 
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index c669f8bd1eab..8edab1533057 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6268,6 +6268,8 @@ static struct sctp_packet *sctp_ootb_pkt_new(
 	if (!transport)
 		goto nomem;
 
+	transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
+
 	/* Cache a route for the transport with the chunk's destination as
 	 * the source address.
 	 */
-- 
cgit v1.2.3


From f1bfe8b5415171b5e70c2a47d399c91bd7c2752e Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:05:04 +0800
Subject: sctp: add udphdr to overhead when udp_port is set

sctp_mtu_payload() is for calculating the frag size before making
chunks from a msg. So we should only add udphdr size to overhead
when udp socks are listening, as only then sctp can handle the
incoming sctp over udp packets and outgoing sctp over udp packets
will be possible.

Note that we can't do this according to transport->encap_port, as
different transports may be set to different values, while the
chunks were made before choosing the transport, we could not be
able to meet all rfc6951#section-5.6 recommends.

v1->v2:
  - Add udp_port for sctp_sock to avoid a potential race issue, it
    will be used in xmit path in the next patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/sctp/sctp.h    | 7 +++++--
 include/net/sctp/structs.h | 1 +
 net/sctp/socket.c          | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

(limited to 'include')

diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index bfd87a0aa2f1..86f74f2fe6de 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -578,10 +578,13 @@ static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
 {
 	__u32 overhead = sizeof(struct sctphdr) + extra;
 
-	if (sp)
+	if (sp) {
 		overhead += sp->pf->af->net_header_len;
-	else
+		if (sp->udp_port)
+			overhead += sizeof(struct udphdr);
+	} else {
 		overhead += sizeof(struct ipv6hdr);
+	}
 
 	if (WARN_ON_ONCE(mtu && mtu <= overhead))
 		mtu = overhead;
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 81464ae2b137..80f71499b543 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -178,6 +178,7 @@ struct sctp_sock {
 	 */
 	__u32 hbinterval;
 
+	__be16 udp_port;
 	__be16 encap_port;
 
 	/* This is the max_retrans value for new associations. */
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 2a9ee9b3e46c..a710917c5ac7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4928,6 +4928,7 @@ static int sctp_init_sock(struct sock *sk)
 	 * be modified via SCTP_PEER_ADDR_PARAMS
 	 */
 	sp->hbinterval  = net->sctp.hb_interval;
+	sp->udp_port    = htons(net->sctp.udp_port);
 	sp->encap_port  = htons(net->sctp.encap_port);
 	sp->pathmaxrxt  = net->sctp.max_retrans_path;
 	sp->pf_retrans  = net->sctp.pf_retrans;
-- 
cgit v1.2.3


From e38d86b354f96e3ed6f5e6c7dbb442d7107fc0bd Mon Sep 17 00:00:00 2001
From: Xin Long <lucien.xin@gmail.com>
Date: Thu, 29 Oct 2020 15:05:08 +0800
Subject: sctp: add the error cause for new encapsulation port restart

This patch is to add the function to make the abort chunk with
the error cause for new encapsulation port restart, defined
on Section 4.4 in draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.

v1->v2:
  - no change.
v2->v3:
  - no need to call htons() when setting nep.cur_port/new_port.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/linux/sctp.h     | 20 ++++++++++++++++++++
 include/net/sctp/sm.h    |  3 +++
 net/sctp/sm_make_chunk.c | 20 ++++++++++++++++++++
 3 files changed, 43 insertions(+)

(limited to 'include')

diff --git a/include/linux/sctp.h b/include/linux/sctp.h
index 76731230bbc5..bb1926589693 100644
--- a/include/linux/sctp.h
+++ b/include/linux/sctp.h
@@ -482,11 +482,13 @@ enum sctp_error {
 	 *  11  Restart of an association with new addresses
 	 *  12  User Initiated Abort
 	 *  13  Protocol Violation
+	 *  14  Restart of an Association with New Encapsulation Port
 	 */
 
 	SCTP_ERROR_RESTART         = cpu_to_be16(0x0b),
 	SCTP_ERROR_USER_ABORT      = cpu_to_be16(0x0c),
 	SCTP_ERROR_PROTO_VIOLATION = cpu_to_be16(0x0d),
+	SCTP_ERROR_NEW_ENCAP_PORT  = cpu_to_be16(0x0e),
 
 	/* ADDIP Section 3.3  New Error Causes
 	 *
@@ -793,4 +795,22 @@ enum {
 	SCTP_FLOWLABEL_VAL_MASK = 0xfffff
 };
 
+/* UDP Encapsulation
+ * draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.html#section-4-4
+ *
+ *   The error cause indicating an "Restart of an Association with
+ *   New Encapsulation Port"
+ *
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |        Cause Code = 14        |       Cause Length = 8        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Current Encapsulation Port  |     New Encapsulation Port    |
+ * +-------------------------------+-------------------------------+
+ */
+struct sctp_new_encap_port_hdr {
+	__be16 cur_port;
+	__be16 new_port;
+};
+
 #endif /* __LINUX_SCTP_H__ */
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index a499341472ad..fd223c94589a 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -221,6 +221,9 @@ struct sctp_chunk *sctp_make_violation_paramlen(
 struct sctp_chunk *sctp_make_violation_max_retrans(
 					const struct sctp_association *asoc,
 					const struct sctp_chunk *chunk);
+struct sctp_chunk *sctp_make_new_encap_port(
+					const struct sctp_association *asoc,
+					const struct sctp_chunk *chunk);
 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
 				       const struct sctp_transport *transport);
 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 21d0ff1c6ab9..f77484df097b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1142,6 +1142,26 @@ nodata:
 	return retval;
 }
 
+struct sctp_chunk *sctp_make_new_encap_port(const struct sctp_association *asoc,
+					    const struct sctp_chunk *chunk)
+{
+	struct sctp_new_encap_port_hdr nep;
+	struct sctp_chunk *retval;
+
+	retval = sctp_make_abort(asoc, chunk,
+				 sizeof(struct sctp_errhdr) + sizeof(nep));
+	if (!retval)
+		goto nodata;
+
+	sctp_init_cause(retval, SCTP_ERROR_NEW_ENCAP_PORT, sizeof(nep));
+	nep.cur_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
+	nep.new_port = chunk->transport->encap_port;
+	sctp_addto_chunk(retval, sizeof(nep), &nep);
+
+nodata:
+	return retval;
+}
+
 /* Make a HEARTBEAT chunk.  */
 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
 				       const struct sctp_transport *transport)
-- 
cgit v1.2.3