/* * pdesc.h * ptunnel is licensed under the BSD license: * * Copyright (c) 2004-2011, Daniel Stoedle , * Yellow Lemon Software. All rights reserved. * * Copyright (c) 2017-2019, Toni Uhlig * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * - Neither the name of the Yellow Lemon Software nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * Contacting the author: * You can get in touch with me, Daniel Stødle (that's the Norwegian letter oe, * in case your text editor didn't realize), here: * * The official ptunnel website is here: * * * Note that the source code is best viewed with tabs set to 4 spaces. */ #ifndef PDESC_H #define PDESC_H 1 #include #ifndef WIN32 #include #include #include #endif #include "pkt.h" #include "challenge.h" #include "pconfig.h" /** forward_desc_t: Describes a piece of that needs to be forwarded. This * structure is used for receiving data from the network, and for subsequent * forwarding over TCP: * * 1. Client sends data to proxy over ICMP * 2. Proxy receives the data, and puts it into a forward_desc_t * 3. The proxy starts send()-ing the data over the TCP socket to the destination, * decreasing forward_desc_t->remaining with the number of bytes transferred. * 4. Once remaining reaches 0, the forward_desc_t is removed from the receive * ring. * * The same procedure is followed in proxy-to-client communication. Just replace * proxy with client and vice versa in the list above. */ typedef struct forward_desc_t { /** ping_tunnel_pkt_t seq_no */ uint16_t seq_no; /** length of data */ uint16_t length; /** amount of data not yet transferred */ size_t remaining; char data[0]; } forward_desc_t; /** icmp_desc_t: This structure is used to track the ICMP packets sent by either * the client or proxy. The last_resend variable is used to prevent resending * the packet too often. Once the packet is acknowledged by the remote end, * it will be removed from the send-ring, freeing up space for more outgoing * ICMP packets. */ typedef struct icmp_desc_t { /** total length of ICMP packet, including ICMP header and ptunnel data. */ uint16_t pkt_len; double last_resend; uint16_t seq_no; uint16_t icmp_id; icmp_echo_packet_t *pkt; } icmp_desc_t; /** xfer_stats_t: Various transfer statistics, such as bytes sent and received, * number of ping packets sent/received, etc. */ typedef struct xfer_stats_t { double bytes_in; double bytes_out; uint32_t icmp_in; uint32_t icmp_out; uint32_t icmp_resent; uint32_t icmp_ack_out; } xfer_stats_t; /** proxy_desc_t: This massive structure describes a tunnel instance. */ typedef struct proxy_desc_t { /** ICMP or UDP socket */ int sock; /** number of bytes in receive buffer */ int bytes; /** set to true once this instance should be removed */ int should_remove; /** data buffer, used to receive ping and pong packets */ char *buf; uint16_t id_no; uint16_t my_seq; uint16_t ping_seq; uint16_t next_remote_seq; uint16_t pkt_type; uint16_t remote_ack_val; uint16_t icmp_id; /** first available slot in recv ring */ int recv_idx; /** current slot in recv ring being transferred */ int recv_xfer_idx; /** first available slot in send ring */ int send_idx; /** first packet in send ring not yet acked */ int send_first_ack; /** number of items in recv ring awaiting send */ int recv_wait_send; /** number of items in send ring awaiting ack */ int send_wait_ack; int next_resend_start; int authenticated; /** Contains the challenge, if used. */ challenge_t *challenge; /** Protocol state */ uint32_t state; /** Either kProxy_flag or kUser_flag */ uint32_t type_flag; /** IP and port to which data should be forwarded. */ uint32_t dst_ip; uint32_t dst_port; /** Same as above */ struct sockaddr_in dest_addr; /** Time when last ack packet was sent. */ double last_ack; /** Time when a packet was last received. */ double last_activity; double last_data_activity; uint16_t window_size; double ack_interval; double resend_interval; uint16_t payload_size; uint16_t extended_options[4]; icmp_desc_t *send_ring; forward_desc_t **recv_ring; xfer_stats_t xfer; struct proxy_desc_t *next; } proxy_desc_t; proxy_desc_t* create_and_insert_proxy_desc(uint16_t id_no, uint16_t icmp_id, int sock, struct sockaddr_in *addr, uint32_t dst_ip, uint32_t dst_port, uint32_t init_state, uint32_t type); void remove_proxy_desc(proxy_desc_t *cur, proxy_desc_t *prev); void remove_proxy_desc_rings(proxy_desc_t *cur); forward_desc_t* create_fwd_desc(uint16_t seq_no, uint32_t data_len, char *data); int queue_packet(int sock_fd, proxy_desc_t *cur, char *buf, size_t bufsiz, uint32_t dest_ip, uint32_t dest_port, uint32_t state); uint32_t send_packets(forward_desc_t *ring[], int *xfer_idx, int *await_send, int *sock, uint16_t window_size); #endif