#include "buffer.h"
Go to the source code of this file.
Data Structures | |
| struct | frame |
| Packet geometry parameters. More... | |
Macros | |
| #define | ETHERNET_MTU 1500 |
| #define | TUN_MTU_MIN 100 |
| #define | LINK_MTU_DEFAULT 1500 |
| #define | TUN_MTU_DEFAULT 1500 |
| #define | TAP_MTU_EXTRA_DEFAULT 32 |
| #define | MSSFIX_DEFAULT 1492 |
| #define | TLS_MTU_DEFAULT 1250 |
| #define | PAYLOAD_ALIGN 4 |
| #define | BUF_SIZE(f) ((f)->buf.headroom + (f)->buf.payload_size + (f)->buf.tailroom) |
Functions | |
| void | frame_print (const struct frame *frame, int level, const char *prefix) |
| void | set_mtu_discover_type (socket_descriptor_t sd, int mtu_type, sa_family_t proto_af) |
| int | translate_mtu_discover_type_name (const char *name) |
| size_t | frame_calculate_payload_size (const struct frame *frame, const struct options *options, const struct key_type *kt) |
| Calculates the size of the payload according to tun-mtu and tap overhead. More... | |
| size_t | frame_calculate_payload_overhead (size_t extra_tun, const struct options *options, const struct key_type *kt) |
| Calculates the size of the payload overhead according to tun-mtu and tap overhead. More... | |
| size_t | frame_calculate_protocol_header_size (const struct key_type *kt, const struct options *options, bool occ) |
| Calculates the size of the OpenVPN protocol header. More... | |
| size_t | calc_options_string_link_mtu (const struct options *options, const struct frame *frame) |
| Calculate the link-mtu to advertise to our peer. More... | |
| unsigned int | calc_packet_id_size_dc (const struct options *options, const struct key_type *kt) |
| Return the size of the packet ID size that is currently in use by cipher and options for the data channel. More... | |
| void | alloc_buf_sock_tun (struct buffer *buf, const struct frame *frame) |
Macro Definition Documentation
◆ BUF_SIZE
| #define BUF_SIZE | ( | f | ) | ((f)->buf.headroom + (f)->buf.payload_size + (f)->buf.tailroom) |
◆ ETHERNET_MTU
◆ LINK_MTU_DEFAULT
◆ MSSFIX_DEFAULT
◆ PAYLOAD_ALIGN
◆ TAP_MTU_EXTRA_DEFAULT
◆ TLS_MTU_DEFAULT
◆ TUN_MTU_DEFAULT
◆ TUN_MTU_MIN
Function Documentation
◆ alloc_buf_sock_tun()
Definition at line 42 of file mtu.c.
References alloc_buf(), ASSERT, frame::buf, buf_init, buf_safe(), BUF_SIZE, frame::headroom, buffer::len, and frame::payload_size.
Referenced by overlapped_io_init(), and socket_frame_init().
◆ calc_options_string_link_mtu()
Calculate the link-mtu to advertise to our peer.
The actual value is not relevant, because we will possibly perform data channel cipher negotiation after this, but older clients will log warnings if we do not supply them the value they expect. This assumes that the traditional cipher/auth directives in the config match the config of the peer.
Definition at line 152 of file mtu.c.
References options::authname, options::ciphername, frame_calculate_payload_size(), frame_calculate_protocol_header_size(), init_key_type(), options::shared_secret_file, options::tls_client, and options::tls_server.
Referenced by options_string(), and test_occ_mtu_calculation().
◆ calc_packet_id_size_dc()
Return the size of the packet ID size that is currently in use by cipher and options for the data channel.
Definition at line 53 of file mtu.c.
References key_type::cipher, cipher_kt_mode_ofb_cfb(), packet_id_size(), options::tls_client, and options::tls_server.
Referenced by frame_calculate_fragment(), frame_calculate_payload_overhead(), and frame_calculate_protocol_header_size().
◆ frame_calculate_payload_overhead()
| size_t frame_calculate_payload_overhead | ( | size_t | extra_tun, |
| const struct options * | options, | ||
| const struct key_type * | kt | ||
| ) |
Calculates the size of the payload overhead according to tun-mtu and tap overhead.
This all the overhead that is considered part of the payload itself. The compression and fragmentation header and extra header from tap are considered part of this overhead that increases the payload larger than tun-mtu.
In CBC mode, the IV is part of the payload instead of part of the OpenVPN protocol header and is included in the returned value.
In this context payload is identical to the size of the plaintext and this method can be also understand as number of bytes that are added to the plaintext before encryption.
- [IP][UDP][OPENVPN PROTOCOL HEADER][ PAYLOAD incl compression header ]
Definition at line 101 of file mtu.c.
References compress_options::alg, calc_packet_id_size_dc(), options::ce, key_type::cipher, cipher_kt_mode_cbc(), options::comp, COMP_ALG_LZ4, COMP_ALG_LZO, COMP_ALG_STUB, and connection_entry::fragment.
Referenced by check_send_occ_msg_dowork(), frame_calculate_mssfix(), and frame_calculate_payload_size().
◆ frame_calculate_payload_size()
| size_t frame_calculate_payload_size | ( | const struct frame * | frame, |
| const struct options * | options, | ||
| const struct key_type * | kt | ||
| ) |
Calculates the size of the payload according to tun-mtu and tap overhead.
In this context payload is identical to the size of the plaintext. This also includes compression, fragmentation overhead, and packet id in CBC mode if these options are used.
- [IP][UDP][OPENVPN PROTOCOL HEADER][ PAYLOAD incl compression header ]
Definition at line 142 of file mtu.c.
References options::ce, frame::extra_tun, frame_calculate_payload_overhead(), and connection_entry::tun_mtu.
Referenced by calc_options_string_link_mtu(), and check_send_occ_load_test_dowork().
◆ frame_calculate_protocol_header_size()
| size_t frame_calculate_protocol_header_size | ( | const struct key_type * | kt, |
| const struct options * | options, | ||
| bool | occ | ||
| ) |
Calculates the size of the OpenVPN protocol header.
This includes the crypto IV/tag/HMAC but does not include the IP encapsulation
This does NOT include the padding and rounding of CBC size as the users (mssfix/fragment) of this function need to adjust for this and add it themselves.
[IP][UDP][ OPENVPN PROTOCOL HEADER][PAYLOAD incl compression header]
- Parameters
-
kt the key_type to use to calculate the crypto overhead options the options struct to be used to calculate occ Use the calculation for the OCC link-mtu
- Returns
- size of the overhead in bytes
Definition at line 63 of file mtu.c.
References calc_packet_id_size_dc(), calculate_crypto_overhead(), options::ce, connection_entry::proto, proto_is_tcp(), proto_is_udp(), connection_entry::socks_proxy_server, options::tls_client, options::tls_server, and options::use_peer_id.
Referenced by calc_options_string_link_mtu(), check_send_occ_load_test_dowork(), check_send_occ_msg_dowork(), frame_calculate_fragment(), frame_calculate_mssfix(), and get_frame_mtu().
◆ frame_print()
| void frame_print | ( | const struct frame * | frame, |
| int | level, | ||
| const char * | prefix | ||
| ) |
Definition at line 195 of file mtu.c.
References alloc_buf_gc(), frame::buf, buf_printf(), buffer::data, frame::extra_tun, gc_free(), gc_new(), frame::headroom, frame::max_fragment_size, msg, frame::mss_fix, frame::payload_size, frame::tailroom, frame::tun_max_mtu, and frame::tun_mtu.
Referenced by do_init_frame_tls(), do_print_data_channel_mtu_parms(), get_frame_mtu(), and tls_session_update_crypto_params_do_work().
◆ set_mtu_discover_type()
| void set_mtu_discover_type | ( | socket_descriptor_t | sd, |
| int | mtu_type, | ||
| sa_family_t | proto_af | ||
| ) |
Definition at line 225 of file mtu.c.
References M_ERR, M_FATAL, msg, and MTUDISC_NOT_SUPPORTED_MSG.
Referenced by phase2_set_socket_flags().
◆ translate_mtu_discover_type_name()
| int translate_mtu_discover_type_name | ( | const char * | name | ) |
Definition at line 261 of file mtu.c.
References M_FATAL, msg, and MTUDISC_NOT_SUPPORTED_MSG.
Referenced by add_option().
