From 84df3d4d0278e21a36a453bfee94799f0df67c2a Mon Sep 17 00:00:00 2001 From: Hans Nilsson Date: Tue, 6 Oct 2015 21:18:23 +0200 Subject: ssh: Option max_channels added. It actually counts the number of subsystem alive. Allocating a channel does not consume any resources (except some cpu cycles), but the subsystem start spawns processes. --- lib/ssh/doc/src/ssh.xml | 9 +++++ lib/ssh/src/ssh.erl | 4 ++ lib/ssh/src/ssh_connection.erl | 27 ++++++++++--- lib/ssh/test/ssh_connection_SUITE.erl | 75 ++++++++++++++++++++++++++++++++++- 4 files changed, 108 insertions(+), 7 deletions(-) diff --git a/lib/ssh/doc/src/ssh.xml b/lib/ssh/doc/src/ssh.xml index cf5e8f1aff..37ed016099 100644 --- a/lib/ssh/doc/src/ssh.xml +++ b/lib/ssh/doc/src/ssh.xml @@ -501,6 +501,15 @@ kex is implicit but public_key is set explicitly.

+ + +

The maximum number of channels with active remote subsystem that are accepted for + each connection to this daemon

+

By default, this option is not set. This means that the number is not limited. +

+ + +

If set to false (the default value), only one login is handled at a time. diff --git a/lib/ssh/src/ssh.erl b/lib/ssh/src/ssh.erl index 132de71aed..ee44324c12 100644 --- a/lib/ssh/src/ssh.erl +++ b/lib/ssh/src/ssh.erl @@ -385,6 +385,8 @@ handle_option([{rekey_limit, _} = Opt|Rest], SocketOptions, SshOptions) -> handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]); handle_option([{max_sessions, _} = Opt|Rest], SocketOptions, SshOptions) -> handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]); +handle_option([{max_channels, _} = Opt|Rest], SocketOptions, SshOptions) -> + handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]); handle_option([{negotiation_timeout, _} = Opt|Rest], SocketOptions, SshOptions) -> handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]); handle_option([{parallel_login, _} = Opt|Rest], SocketOptions, SshOptions) -> @@ -443,6 +445,8 @@ handle_ssh_option({connect_timeout, Value} = Opt) when is_integer(Value); Value Opt; handle_ssh_option({max_sessions, Value} = Opt) when is_integer(Value), Value>0 -> Opt; +handle_ssh_option({max_channels, Value} = Opt) when is_integer(Value), Value>0 -> + Opt; handle_ssh_option({negotiation_timeout, Value} = Opt) when is_integer(Value); Value == infinity -> Opt; handle_ssh_option({parallel_login, Value} = Opt) when Value==true ; Value==false -> diff --git a/lib/ssh/src/ssh_connection.erl b/lib/ssh/src/ssh_connection.erl index 64d2113125..266c64fd4f 100644 --- a/lib/ssh/src/ssh_connection.erl +++ b/lib/ssh/src/ssh_connection.erl @@ -935,14 +935,27 @@ encode_ip(Addr) when is_list(Addr) -> end end. -start_channel(Cb, Id, Args, SubSysSup) -> - start_channel(Cb, Id, Args, SubSysSup, undefined). +start_channel(Cb, Id, Args, SubSysSup, Opts) -> + start_channel(Cb, Id, Args, SubSysSup, undefined, Opts). -start_channel(Cb, Id, Args, SubSysSup, Exec) -> +start_channel(Cb, Id, Args, SubSysSup, Exec, Opts) -> ChildSpec = child_spec(Cb, Id, Args, Exec), ChannelSup = ssh_subsystem_sup:channel_supervisor(SubSysSup), + assert_limit_num_channels_not_exceeded(ChannelSup, Opts), ssh_channel_sup:start_child(ChannelSup, ChildSpec). +assert_limit_num_channels_not_exceeded(ChannelSup, Opts) -> + MaxNumChannels = proplists:get_value(max_channels, Opts, infinity), + NumChannels = length([x || {_,_,worker,[ssh_channel]} <- + supervisor:which_children(ChannelSup)]), + if + %% Note that NumChannels is BEFORE starting a new one + NumChannels < MaxNumChannels -> + ok; + true -> + throw(max_num_channels_exceeded) + end. + %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- @@ -998,9 +1011,11 @@ child_spec(Callback, Id, Args, Exec) -> start_cli(#connection{cli_spec = no_cli}, _) -> {error, cli_disabled}; -start_cli(#connection{cli_spec = {CbModule, Args}, exec = Exec, +start_cli(#connection{options = Options, + cli_spec = {CbModule, Args}, + exec = Exec, sub_system_supervisor = SubSysSup}, ChannelId) -> - start_channel(CbModule, ChannelId, Args, SubSysSup, Exec). + start_channel(CbModule, ChannelId, Args, SubSysSup, Exec, Options). start_subsytem(BinName, #connection{options = Options, sub_system_supervisor = SubSysSup}, @@ -1008,7 +1023,7 @@ start_subsytem(BinName, #connection{options = Options, Name = binary_to_list(BinName), case check_subsystem(Name, Options) of {Callback, Opts} when is_atom(Callback), Callback =/= none -> - start_channel(Callback, ChannelId, Opts, SubSysSup); + start_channel(Callback, ChannelId, Opts, SubSysSup, Options); {Other, _} when Other =/= none -> {error, legacy_option_not_supported} end. diff --git a/lib/ssh/test/ssh_connection_SUITE.erl b/lib/ssh/test/ssh_connection_SUITE.erl index fbcf06290a..37bba07440 100644 --- a/lib/ssh/test/ssh_connection_SUITE.erl +++ b/lib/ssh/test/ssh_connection_SUITE.erl @@ -48,7 +48,8 @@ all() -> gracefull_invalid_long_start, gracefull_invalid_long_start_no_nl, stop_listener, - start_subsystem_on_closed_channel + start_subsystem_on_closed_channel, + max_channels_option ]. groups() -> [{openssh, [], payload() ++ ptty()}]. @@ -605,6 +606,78 @@ start_subsystem_on_closed_channel(Config) -> ssh:close(ConnectionRef), ssh:stop_daemon(Pid). +%%-------------------------------------------------------------------- +max_channels_option() -> + [{doc, "Test max_channels option"}]. + +max_channels_option(Config) when is_list(Config) -> + PrivDir = ?config(priv_dir, Config), + UserDir = filename:join(PrivDir, nopubkey), % to make sure we don't use public-key-auth + file:make_dir(UserDir), + SysDir = ?config(data_dir, Config), + {Pid, Host, Port} = ssh_test_lib:daemon([{system_dir, SysDir}, + {user_dir, UserDir}, + {password, "morot"}, + {max_channels, 3}, + {subsystems, [{"echo_n", {ssh_echo_server, [4000000]}}]} + ]), + + ConnectionRef = ssh_test_lib:connect(Host, Port, [{silently_accept_hosts, true}, + {user, "foo"}, + {password, "morot"}, + {user_interaction, true}, + {user_dir, UserDir}]), + + {ok, ChannelId0} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, ChannelId1} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, ChannelId2} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, ChannelId3} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, ChannelId4} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, ChannelId5} = ssh_connection:session_channel(ConnectionRef, infinity), + {ok, _ChannelId6} = ssh_connection:session_channel(ConnectionRef, infinity), + + %%%---- shell + ok = ssh_connection:shell(ConnectionRef,ChannelId0), + receive + {ssh_cm,ConnectionRef, {data, ChannelId0, 0, <<"Eshell",_/binary>>}} -> + ok + after 5000 -> + ct:fail("CLI Timeout") + end, + + %%%---- subsystem "echo_n" + success = ssh_connection:subsystem(ConnectionRef, ChannelId1, "echo_n", infinity), + + %%%---- exec #1 + success = ssh_connection:exec(ConnectionRef, ChannelId2, "testing1.\n", infinity), + receive + {ssh_cm, ConnectionRef, {data, ChannelId2, 0, <<"testing1",_/binary>>}} -> + ok + after 5000 -> + ct:fail("Exec #1 Timeout") + end, + + %%%---- ptty + success = ssh_connection:ptty_alloc(ConnectionRef, ChannelId3, []), + + %%%---- exec #2 + failure = ssh_connection:exec(ConnectionRef, ChannelId4, "testing2.\n", infinity), + + %%%---- close the shell + ok = ssh_connection:send(ConnectionRef, ChannelId0, "exit().\n", 5000), + + %%%---- exec #3 + success = ssh_connection:exec(ConnectionRef, ChannelId5, "testing3.\n", infinity), + receive + {ssh_cm, ConnectionRef, {data, ChannelId5, 0, <<"testing3",_/binary>>}} -> + ok + after 5000 -> + ct:fail("Exec #3 Timeout") + end, + + ssh:close(ConnectionRef), + ssh:stop_daemon(Pid). + %%-------------------------------------------------------------------- %% Internal functions ------------------------------------------------ %%-------------------------------------------------------------------- -- cgit v1.2.3