From 046c052b475e7119b6a30e3483e2888fc606a2f8 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 29 Oct 2020 15:05:10 +0800 Subject: sctp: enable udp tunneling socks 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. v1->v2: - Also update ctl_sock udp_port in proc_sctp_do_udp_port() where netns udp_port gets changed. v2->v3: - Call htons() when setting sk udp_port from netns udp_port. v3->v4: - Not call sctp_udp_sock_start() when new_value is 0. - Add udp_port entry in ip-sysctl.rst. v4->v5: - Not call sctp_udp_sock_start/stop() in sctp_ctrlsock_init/exit(). - Improve the description of udp_port in ip-sysctl.rst. Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski --- Documentation/networking/ip-sysctl.rst | 15 ++++++++++ net/sctp/sysctl.c | 52 ++++++++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index dad3ba952989..2aaf40b2d2cd 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2642,6 +2642,21 @@ addr_scope_policy - INTEGER Default: 1 +udp_port - INTEGER + The listening port for the local UDP tunneling sock. Normally it's + using the IANA-assigned UDP port number 9899 (sctp-tunneling). + + This UDP sock is used for processing the incoming UDP-encapsulated + SCTP packets (from RFC6951), and shared by all applications in the + same net namespace. This UDP sock will be closed when the value is + set to 0. + + The value will also be used to set the src port of the UDP header + for the outgoing UDP-encapsulated SCTP packets. For the dest port, + please refer to 'encap_port' below. + + Default: 0 + encap_port - INTEGER The default remote UDP encapsulation port. diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c index ecc1b5e4c297..e92df779af73 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, @@ -291,6 +293,15 @@ static struct ctl_table sctp_net_table[] = { .mode = 0644, .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, @@ -487,6 +498,47 @@ 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) { + struct sock *sk = net->sctp.ctl_sock; + + if (new_value > max || new_value < min) + return -EINVAL; + + net->sctp.udp_port = new_value; + sctp_udp_sock_stop(net); + if (new_value) { + ret = sctp_udp_sock_start(net); + if (ret) + net->sctp.udp_port = 0; + } + + /* Update the value in the control socket */ + lock_sock(sk); + sctp_sk(sk)->udp_port = htons(net->sctp.udp_port); + release_sock(sk); + } + + return ret; +} + int sctp_sysctl_net_register(struct net *net) { struct ctl_table *table; -- cgit