@@ -1170,6 +1170,8 @@ void tcp_set_state(struct sock *sk, int state);
void tcp_done(struct sock *sk);
+int tcp_abort(struct sock *sk, int err);
+
static inline void tcp_sack_reset(struct tcp_options_received *rx_opt)
{
rx_opt->dsack = 0;
@@ -436,6 +436,19 @@ config INET_UDP_DIAG
Support for UDP socket monitoring interface used by the ss tool.
If unsure, say Y.
+config INET_DIAG_DESTROY
+ bool "INET: allow privileged process to administratively close sockets"
+ depends on INET_DIAG
+ default n
+ ---help---
+ Provides a SOCK_DESTROY operation that allows privileged processes
+ (e.g., a connection manager or a network administration tool such as
+ ss) to close sockets opened by other processes. Closing a socket in
+ this way interrupts any blocking read/write/connect operations on
+ the socket and causes future socket calls to behave as if the socket
+ had been disconnected.
+ If unsure, say N.
+
menuconfig TCP_CONG_ADVANCED
bool "TCP: advanced congestion control"
---help---
@@ -3080,6 +3080,38 @@ void tcp_done(struct sock *sk)
}
EXPORT_SYMBOL_GPL(tcp_done);
+int tcp_abort(struct sock *sk, int err)
+{
+ if (!sk_fullsock(sk)) {
+ sock_gen_put(sk);
+ return -EOPNOTSUPP;
+ }
+
+ /* Don't race with userspace socket closes such as tcp_close. */
+ lock_sock(sk);
+
+ /* Don't race with BH socket closes such as inet_csk_listen_stop. */
+ local_bh_disable();
+ bh_lock_sock(sk);
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ sk->sk_err = err;
+ /* This barrier is coupled with smp_rmb() in tcp_poll() */
+ smp_wmb();
+ sk->sk_error_report(sk);
+ if (tcp_need_reset(sk->sk_state))
+ tcp_send_active_reset(sk, GFP_ATOMIC);
+ tcp_done(sk);
+ }
+
+ bh_unlock_sock(sk);
+ local_bh_enable();
+ release_sock(sk);
+ sock_put(sk);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tcp_abort);
+
extern struct tcp_congestion_ops tcp_reno;
static __initdata unsigned long thash_entries;
@@ -10,6 +10,8 @@
*/
#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
#include <linux/tcp.h>
@@ -46,12 +48,29 @@ static int tcp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
return inet_diag_dump_one_icsk(&tcp_hashinfo, in_skb, nlh, req);
}
+#ifdef CONFIG_INET_DIAG_DESTROY
+static int tcp_diag_destroy(struct sk_buff *in_skb,
+ const struct inet_diag_req_v2 *req)
+{
+ struct net *net = sock_net(in_skb->sk);
+ struct sock *sk = inet_diag_find_one_icsk(net, &tcp_hashinfo, req);
+
+ if (IS_ERR(sk))
+ return PTR_ERR(sk);
+
+ return sock_diag_destroy(sk, ECONNABORTED);
+}
+#endif
+
static const struct inet_diag_handler tcp_diag_handler = {
.dump = tcp_diag_dump,
.dump_one = tcp_diag_dump_one,
.idiag_get_info = tcp_diag_get_info,
.idiag_type = IPPROTO_TCP,
.idiag_info_size = sizeof(struct tcp_info),
+#ifdef CONFIG_INET_DIAG_DESTROY
+ .destroy = tcp_diag_destroy,
+#endif
};
static int __init tcp_diag_init(void)
@@ -2342,6 +2342,7 @@ struct proto tcp_prot = {
.destroy_cgroup = tcp_destroy_cgroup,
.proto_cgroup = tcp_proto_cgroup,
#endif
+ .diag_destroy = tcp_abort,
};
EXPORT_SYMBOL(tcp_prot);
@@ -1890,6 +1890,7 @@ struct proto tcpv6_prot = {
.proto_cgroup = tcp_proto_cgroup,
#endif
.clear_sk = tcp_v6_clear_sk,
+ .diag_destroy = tcp_abort,
};
static const struct inet6_protocol tcpv6_protocol = {
This implements SOCK_DESTROY for TCP sockets. It causes all blocking calls on the socket to fail fast with ECONNABORTED and causes a protocol close of the socket. It informs the other end of the connection by sending a RST, i.e., initiating a TCP ABORT as per RFC 793. ECONNABORTED was chosen for consistency with FreeBSD. Signed-off-by: Lorenzo Colitti <lorenzo@google.com> --- include/net/tcp.h | 2 ++ net/ipv4/Kconfig | 13 +++++++++++++ net/ipv4/tcp.c | 32 ++++++++++++++++++++++++++++++++ net/ipv4/tcp_diag.c | 19 +++++++++++++++++++ net/ipv4/tcp_ipv4.c | 1 + net/ipv6/tcp_ipv6.c | 1 + 6 files changed, 68 insertions(+)