[PATCH net-next 15/15] sctp: enable udp tunneling socks

[Xin Long]

This patch is to enable udp tunneling socks by calling
sctp_udp_sock_start() in sctp_ctrlsock_init(), and
sctp_udp_sock_stop() in sctp_ctrlsock_exit().

Also add sysctl udp_port to allow changing the listening
sock's port by users.

Wit this patch, the whole sctp over udp feature can be
enabled and used.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/sctp/protocol.c |  5 +++++
 net/sctp/sysctl.c   | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 6606a63..4b63883 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1466,6 +1466,10 @@ static int __net_init sctp_ctrlsock_init(struct net *net)
        if (status)
                pr_err("Failed to initialize the SCTP control sock\n");
 
+       status = sctp_udp_sock_start(net);
+       if (status)
+               pr_err("Failed to initialize the SCTP udp tunneling sock\n");
+
        return status;
 }
 
@@ -1473,6 +1477,7 @@ static void __net_exit sctp_ctrlsock_exit(struct net *net)
 {
        /* Free the control endpoint.  */
        inet_ctl_sock_destroy(net->sctp.ctl_sock);
+       sctp_udp_sock_stop(net);
 }
 
 static struct pernet_operations sctp_ctrlsock_ops = {
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index ecc1b5e..7afe904 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -49,6 +49,8 @@ static int proc_sctp_do_rto_min(struct ctl_table *ctl, int 
write,
                                void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write, void *buffer,
                                size_t *lenp, loff_t *ppos);
+static int proc_sctp_do_udp_port(struct ctl_table *ctl, int write, void 
*buffer,
+                                size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
                                   void *buffer, size_t *lenp, loff_t *ppos);
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
@@ -292,6 +294,15 @@ static struct ctl_table sctp_net_table[] = {
                .proc_handler   = proc_dointvec,
        },
        {
+               .procname       = "udp_port",
+               .data           = &init_net.sctp.udp_port,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_sctp_do_udp_port,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = &udp_port_max,
+       },
+       {
                .procname       = "encap_port",
                .data           = &init_net.sctp.encap_port,
                .maxlen         = sizeof(int),
@@ -487,6 +498,38 @@ static int proc_sctp_do_auth(struct ctl_table *ctl, int 
write,
        return ret;
 }
 
+static int proc_sctp_do_udp_port(struct ctl_table *ctl, int write,
+                                void *buffer, size_t *lenp, loff_t *ppos)
+{
+       struct net *net = current->nsproxy->net_ns;
+       unsigned int min = *(unsigned int *)ctl->extra1;
+       unsigned int max = *(unsigned int *)ctl->extra2;
+       struct ctl_table tbl;
+       int ret, new_value;
+
+       memset(&tbl, 0, sizeof(struct ctl_table));
+       tbl.maxlen = sizeof(unsigned int);
+
+       if (write)
+               tbl.data = &new_value;
+       else
+               tbl.data = &net->sctp.udp_port;
+
+       ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
+       if (write && ret == 0) {
+               if (new_value > max || new_value < min)
+                       return -EINVAL;
+
+               net->sctp.udp_port = new_value;
+               sctp_udp_sock_stop(net);
+               ret = sctp_udp_sock_start(net);
+               if (ret)
+                       net->sctp.udp_port = 0;
+       }
+
+       return ret;
+}
+
 int sctp_sysctl_net_register(struct net *net)
 {
        struct ctl_table *table;
-- 
2.1.0