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: Boris Pismenny <borisp@xxxxxxxxxxxx> Signed-off-by: Dave Watson <davejwatson@xxxxxx> --- include/net/inet_connection_sock.h | 4 ++ include/net/tcp.h | 25 +++++++ include/uapi/linux/tcp.h | 1 + net/ipv4/Makefile | 2 +- net/ipv4/sysctl_net_ipv4.c | 25 +++++++ net/ipv4/tcp.c | 28 ++++++++ net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_ulp.c | 134 +++++++++++++++++++++++++++++++++++++ 8 files changed, 220 insertions(+), 1 deletion(-) create mode 100644 net/ipv4/tcp_ulp.c diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index c7a5779..13e4c89 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -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, diff --git a/include/net/tcp.h b/include/net/tcp.h index 82462db..fcc39f8 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1992,4 +1992,29 @@ 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 */ diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 38a2b07..8204dce 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/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; diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index f83de23..afcb435 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -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 \ diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 86957e9..6a40837c 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -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; } @@ -707,6 +726,12 @@ static struct ctl_table ipv4_table[] = { .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, .maxlen = sizeof(int), diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index aaf663a..9f06faa 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2458,6 +2458,24 @@ 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; @@ -3014,6 +3032,16 @@ 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; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 191b2f7..c2f5538 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -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); diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c new file mode 100644 index 0000000..e2beb80 --- /dev/null +++ b/net/ipv4/tcp_ulp.c @@ -0,0 +1,134 @@ +/* + * Pluggable TCP upper layer protocol support. + * + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson <davejwatson@xxxxxx>. 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(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(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; +} -- 2.9.3