Re-Update: After compared the different result between ssh_message_global_request_reply_success before ssh_channel_open_reverse_forward or after it I found ssh_channel_listen_forward want a reply, so if I reply it immediately, the ssh client then said "ssh_global_request: Global request tcpip-forward success"and can't receive ssh_channel_open_reverse_forward request. Otherwise if I choose to reply it after ssh_channel_open_reverse_forward, the ssh_channel_listen_forward will hang there, continue wait for the reply.
So how to solve this dilemma... Thanks, Yuanzhe ------------------ ???????? ------------------ ??????: "????????????"<945695...@qq.com>; ????????: 2020??4??8??(??????) ????10:36 ??????: "libssh"<libssh@libssh.org>; ????: ??????HOW to use ssh_channel_open_reverse_forward function to implement a reverse tunnel? Re-Update: After change the sshd global_reply_success func location, now I can see the server ssh client side receive the ssh_packet: ssh_global_request: Sent a SSH_MSG_GLOBAL_REQUEST tcpip-forward ssh_socket_pollcallback: Poll callback on socket 632 (POLLIN POLLOUT ), out buffer 0 ssh_packet_socket_callback: packet: read type 90 [len=80,padding=13,comp=66,payload=66] ssh_packet_process: Dispatching handler for packet type 90 ssh_packet_channel_open: Clients wants to open a forwarded-tcpip channel ssh_packet_need_rekey: packet: [data_rekey_needed=0, out_blocks=4, in_blocks=31 ssh_socket_pollcallback: sending control flow event ssh_packet_socket_controlflow_callback: sending channel_write_wontblock callback ssh_socket_pollcallback: Poll callback on socket 632 (POLLOUT ), out buffer 0 ssh_socket_pollcallback: sending control flow event ssh_packet_socket_controlflow_callback: sending channel_write_wontblock callback However, I can't use ssh_message_get to get the channel open request, the ssh client hang here. So... Still need some help :-) Thanks, Yuanzhe ------------------ ???????? ------------------ ??????: "????????????"<945695...@qq.com>; ????????: 2020??4??8??(??????) ????7:07 ??????: "libssh"<libssh@libssh.org>; ????: ??????HOW to use ssh_channel_open_reverse_forward function to implement a reverse tunnel? Update: I open the log level to 3, found out my "server ssh client" side never received the channel_open request, although my local sshd definitely has sent that: channel_open: Creating a channel 43 with 64000 window and 32768 max packet ssh_packet_need_rekey: packet: [data_rekey_needed=0, out_blocks=31, in_blocks=8 packet_send2: packet: wrote [type=90, len=80, padding_size=13, comp=66, payload=66] channel_open: Sent a SSH_MSG_CHANNEL_OPEN type forwarded-tcpip for channel 43 Here my local sshd hang, and server client raised the error "No channel request of this type from server". I tried brute force all messages on "server ssh client", but unfortunately the server is windows, and vcpkg installed libssh didn't contain mics.h, so I don't know how to hardcode a message traverse func, BTW, message callback also not work, maybe it only worked on sshd? Thanks, Yuanzhe ------------------ ???????? ------------------ ??????: "????????????"<945695...@qq.com>; ????????: 2020??4??8??(??????) ????3:13 ??????: "libssh"<libssh@libssh.org>; ????: HOW to use ssh_channel_open_reverse_forward function to implement a reverse tunnel? Hi, I'm trying to implement a simple ssh reverse tunnel with libssh. The condition is I have a home computer(local), and a development server(server), the server is behind a firewall(NAT) and I want program with libssh to do intranet penetration. I run a client on server, connect to sshd on local, then ssh_channel_listen_forward && ssh_channel_accept_forward as tutorial said. But accept function always failed with error ''waiting for incoming connection: No channel request of this type from server''. So turn to the local sshd side, I have registered global_request function(Here I also have a question: what's the difference between message callback and global_request callback? I thought I can handle this kind global_request in message callback, so if I both have message callback and global_request callback, does the global_request come through message callback and global_request callback both?)In it I have handled reply_success, open socket on local, listen to it, allocate a new channel, and call ssh_channel_open_reverse_forward. I guessed I need another sshd on server, to communicate with this channel. But now I don't have code it because I'm not sure whether ssh_channel_accept_forward can handle this situation? Please clarify the architecture here, Thanks! I also stuck at ssh_channel_open_reverse_forward function, it never return. I believe the problem is parameter, remotehost/remoteport/sourcehost/sourceport. I have read the comment, see if I want the local sshd listen at 2222, should I set remotehost as "localhost", remoeport as "2222"? Then what is the sourcehost/souceport represent? the server client connected to my local sshd? Since the server here is in NAT, how could I get it's IP? Please kindly give me some hint on here, especially how the local sshd reverse connect to the server sshd. I tried use openssh -R, I saw without a server side sshd, the tunnel can't be established. So I thought there must be some mechanism, which I need to use ssh_channel_open_reverse_forward && ssh_channel_accept_forward && some magic function :-). Show me the mystery here, THANK U! Appreciate your patient, HAVE A NICE DAY! Yuanzhe
