Commit 734942cc authored by Dave Watson's avatar Dave Watson Committed by David S. Miller

tcp: ULP infrastructure

Add the infrustructure for attaching Upper Layer Protocols (ULPs) over TCP
sockets. Based on a similar infrastructure in tcp_cong.  The idea is that any
ULP can add its own logic by changing the TCP proto_ops structure to its own
methods.

Example usage:

setsockopt(sock, SOL_TCP, TCP_ULP, "tls", sizeof("tls"));

modules will call:
tcp_register_ulp(&tcp_tls_ulp_ops);

to register/unregister their ulp, with an init function and name.

A list of registered ulps will be returned by tcp_get_available_ulp, which is
hooked up to /proc.  Example:

$ cat /proc/sys/net/ipv4/tcp_available_ulp
tls

There is currently no functionality to remove or chain ULPs, but
it should be possible to add these in the future if needed.
Signed-off-by: default avatarBoris Pismenny <borisp@mellanox.com>
Signed-off-by: default avatarDave Watson <davejwatson@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 206f60e1
......@@ -75,6 +75,8 @@ struct inet_connection_sock_af_ops {
* @icsk_pmtu_cookie Last pmtu seen by socket
* @icsk_ca_ops Pluggable congestion control hook
* @icsk_af_ops Operations which are AF_INET{4,6} specific
* @icsk_ulp_ops Pluggable ULP control hook
* @icsk_ulp_data ULP private data
* @icsk_ca_state: Congestion control state
* @icsk_retransmits: Number of unrecovered [RTO] timeouts
* @icsk_pending: Scheduled timer event
......@@ -97,6 +99,8 @@ struct inet_connection_sock {
__u32 icsk_pmtu_cookie;
const struct tcp_congestion_ops *icsk_ca_ops;
const struct inet_connection_sock_af_ops *icsk_af_ops;
const struct tcp_ulp_ops *icsk_ulp_ops;
void *icsk_ulp_data;
unsigned int (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
__u8 icsk_ca_state:6,
icsk_ca_setsockopt:1,
......
......@@ -1991,4 +1991,29 @@ static inline void tcp_listendrop(const struct sock *sk)
enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer);
/*
* Interface for adding Upper Level Protocols over TCP
*/
#define TCP_ULP_NAME_MAX 16
#define TCP_ULP_MAX 128
#define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX)
struct tcp_ulp_ops {
struct list_head list;
/* initialize ulp */
int (*init)(struct sock *sk);
/* cleanup ulp */
void (*release)(struct sock *sk);
char name[TCP_ULP_NAME_MAX];
struct module *owner;
};
int tcp_register_ulp(struct tcp_ulp_ops *type);
void tcp_unregister_ulp(struct tcp_ulp_ops *type);
int tcp_set_ulp(struct sock *sk, const char *name);
void tcp_get_available_ulp(char *buf, size_t len);
void tcp_cleanup_ulp(struct sock *sk);
#endif /* _TCP_H */
......@@ -117,6 +117,7 @@ enum {
#define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */
#define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */
#define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */
#define TCP_ULP 31 /* Attach a ULP to a TCP connection */
struct tcp_repair_opt {
__u32 opt_code;
......
......@@ -8,7 +8,7 @@ obj-y := route.o inetpeer.o protocol.o \
inet_timewait_sock.o inet_connection_sock.o \
tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \
tcp_rate.o tcp_recovery.o \
tcp_rate.o tcp_recovery.o tcp_ulp.o \
tcp_offload.o datagram.o raw.o udp.o udplite.o \
udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \
......
......@@ -360,6 +360,25 @@ static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table,
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (write && ret == 0)
tcp_fastopen_active_timeout_reset();
return ret;
}
static int proc_tcp_available_ulp(struct ctl_table *ctl,
int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, };
int ret;
tbl.data = kmalloc(tbl.maxlen, GFP_USER);
if (!tbl.data)
return -ENOMEM;
tcp_get_available_ulp(tbl.data, TCP_ULP_BUF_MAX);
ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
kfree(tbl.data);
return ret;
}
......@@ -685,6 +704,12 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_ms_jiffies,
},
{
.procname = "tcp_available_ulp",
.maxlen = TCP_ULP_BUF_MAX,
.mode = 0444,
.proc_handler = proc_tcp_available_ulp,
},
{
.procname = "icmp_msgs_per_sec",
.data = &sysctl_icmp_msgs_per_sec,
......
......@@ -2482,6 +2482,24 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
release_sock(sk);
return err;
}
case TCP_ULP: {
char name[TCP_ULP_NAME_MAX];
if (optlen < 1)
return -EINVAL;
val = strncpy_from_user(name, optval,
min_t(long, TCP_ULP_NAME_MAX - 1,
optlen));
if (val < 0)
return -EFAULT;
name[val] = 0;
lock_sock(sk);
err = tcp_set_ulp(sk, name);
release_sock(sk);
return err;
}
default:
/* fallthru */
break;
......@@ -3038,6 +3056,16 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
return -EFAULT;
return 0;
case TCP_ULP:
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, icsk->icsk_ulp_ops->name, len))
return -EFAULT;
return 0;
case TCP_THIN_LINEAR_TIMEOUTS:
val = tp->thin_lto;
break;
......
......@@ -1860,6 +1860,8 @@ void tcp_v4_destroy_sock(struct sock *sk)
tcp_cleanup_congestion_control(sk);
tcp_cleanup_ulp(sk);
/* Cleanup up the write buffer. */
tcp_write_queue_purge(sk);
......
/*
* Pluggable TCP upper layer protocol support.
*
* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
* Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
*
*/
#include<linux/module.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <net/tcp.h>
static DEFINE_SPINLOCK(tcp_ulp_list_lock);
static LIST_HEAD(tcp_ulp_list);
/* Simple linear search, don't expect many entries! */
static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
{
struct tcp_ulp_ops *e;
list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
if (strcmp(e->name, name) == 0)
return e;
}
return NULL;
}
static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
{
const struct tcp_ulp_ops *ulp = NULL;
rcu_read_lock();
ulp = tcp_ulp_find(name);
#ifdef CONFIG_MODULES
if (!ulp && capable(CAP_NET_ADMIN)) {
rcu_read_unlock();
request_module("%s", name);
rcu_read_lock();
ulp = tcp_ulp_find(name);
}
#endif
if (!ulp || !try_module_get(ulp->owner))
ulp = NULL;
rcu_read_unlock();
return ulp;
}
/* Attach new upper layer protocol to the list
* of available protocols.
*/
int tcp_register_ulp(struct tcp_ulp_ops *ulp)
{
int ret = 0;
spin_lock(&tcp_ulp_list_lock);
if (tcp_ulp_find(ulp->name)) {
pr_notice("%s already registered or non-unique name\n",
ulp->name);
ret = -EEXIST;
} else {
list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
}
spin_unlock(&tcp_ulp_list_lock);
return ret;
}
EXPORT_SYMBOL_GPL(tcp_register_ulp);
void tcp_unregister_ulp(struct tcp_ulp_ops *ulp)
{
spin_lock(&tcp_ulp_list_lock);
list_del_rcu(&ulp->list);
spin_unlock(&tcp_ulp_list_lock);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(tcp_unregister_ulp);
/* Build string with list of available upper layer protocl values */
void tcp_get_available_ulp(char *buf, size_t maxlen)
{
struct tcp_ulp_ops *ulp_ops;
size_t offs = 0;
rcu_read_lock();
list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
offs += snprintf(buf + offs, maxlen - offs,
"%s%s",
offs == 0 ? "" : " ", ulp_ops->name);
}
rcu_read_unlock();
}
void tcp_cleanup_ulp(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
if (!icsk->icsk_ulp_ops)
return;
if (icsk->icsk_ulp_ops->release)
icsk->icsk_ulp_ops->release(sk);
module_put(icsk->icsk_ulp_ops->owner);
}
/* Change upper layer protocol for socket */
int tcp_set_ulp(struct sock *sk, const char *name)
{
struct inet_connection_sock *icsk = inet_csk(sk);
const struct tcp_ulp_ops *ulp_ops;
int err = 0;
if (icsk->icsk_ulp_ops)
return -EEXIST;
ulp_ops = __tcp_ulp_find_autoload(name);
if (!ulp_ops)
err = -ENOENT;
else
err = ulp_ops->init(sk);
if (err)
goto out;
icsk->icsk_ulp_ops = ulp_ops;
out:
return err;
}
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