Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

ng_deflate(4) [freebsd man page]

NG_DEFLATE(4)						   BSD Kernel Interfaces Manual 					     NG_DEFLATE(4)

NAME
ng_deflate -- Deflate PPP compression (RFC 1979) netgraph node type SYNOPSIS
#include <sys/types.h> #include <netgraph/ng_deflate.h> DESCRIPTION
The deflate node type implements the Deflate sub-protocols of the Compression Control Protocol (CCP). The node has two hooks, comp for compression and decomp for decompression. Only one of them can be connected at the same time, specifying node's operation mode. Typically that hooks would be connected to the ng_ppp(4) node type hook of the same name. Corresponding ng_ppp(4) node hook must be switched to NG_PPP_DECOMPRESS_FULL mode to permit sending uncompressed frames. HOOKS
This node type supports the following hooks: comp Connection to ng_ppp(4) comp hook. Incoming frames are compressed (if possible) and sent back out the same hook. decomp Connection to ng_ppp(4) decomp hook. Incoming frames are decompressed (if they are compressed), and sent back out the same hook. Only one hook can be connected at the same time, specifying node's operation mode. CONTROL MESSAGES
This node type supports the generic control messages, plus the following: NGM_DEFLATE_CONFIG (config) This command resets and configures the node for a session (i.e., for compression or decompression). This command takes a struct ng_deflate_config as an argument: struct ng_deflate_config { u_char enable; /* node enabled */ u_char windowBits; /* log2(Window size) */ }; The enabled field enables traffic flow through the node. The windowBits specify compression windows size as negotiated by the Compres- sion Control Protocol (CCP) in PPP. NGM_DEFLATE_RESETREQ (resetreq) This message contains no arguments, and is bi-directional. If an error is detected during decompression, this message is sent by the node to the originator of the NGM_DEFLATE_CONFIG message that initiated the session. The receiver should respond by sending a PPP CCP Reset-Request to the peer. This message may also be received by this node type when a CCP Reset-Request or Reset-Ack is received by the local PPP entity. The node will respond by flushing its compression state so the sides can resynchronize. NGM_DEFLATE_GET_STATS (getstats) This control message obtains statistics for a given hook. The statistics are returned in struct ng_deflate_stats: struct ng_deflate_stats { uint64_t FramesPlain; uint64_t FramesComp; uint64_t FramesUncomp; uint64_t InOctets; uint64_t OutOctets; uint64_t Errors; }; NGM_DEFLATE_CLR_STATS (clrstats) This control message clears statistics for a given hook. NGM_DEFLATE_GETCLR_STATS (getclrstats) This control message obtains and clears statistics for a given hook. SHUTDOWN
This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when hook have been disconnected. SEE ALSO
netgraph(4), ng_ppp(4), ngctl(8) J. Woods, PPP Deflate Protocol, RFC 1979. W. Simpson, The Point-to-Point Protocol (PPP), RFC 1661. AUTHORS
Alexander Motin <mav@alkar.net> BUGS
Due to nature of netgraph PPP implementation there are possible race conditions between data packet and ResetAck CCP packet in case of packet loss. As result, packet loss can produce bigger performance degradation than supposed by protocol. BSD
December 23, 2006 BSD

Check Out this Related Man Page

NG_MPPC(4)						   BSD Kernel Interfaces Manual 						NG_MPPC(4)

NAME
ng_mppc -- Microsoft MPPC/MPPE compression and encryption netgraph node type SYNOPSIS
#include <sys/types.h> #include <netgraph/ng_mppc.h> DESCRIPTION
The mppc node type implements the Microsoft Point-to-Point Compression (MPPC) and Microsoft Point-to-Point Encryption (MPPE) sub-protocols of the PPP protocol. These protocols are often used in conjunction with the Point-to-Point Tunneling Protocol (PPTP). The node has two hooks, comp for compression and decomp for decompression. Typically one or both of these hooks would be connected to the ng_ppp(4) node type hook of the same name. Each direction of traffic flow is independent of the other. HOOKS
This node type supports the following hooks: comp Connection to ng_ppp(4) comp hook. Incoming frames are compressed and/or encrypted, and sent back out the same hook. decomp Connection to ng_ppp(4) decomp hook. Incoming frames are decompressed and/or decrypted, and sent back out the same hook. CONTROL MESSAGES
This node type supports the generic control messages, plus the following: NGM_MPPC_CONFIG_COMP This command resets and configures the node for a session in the outgoing traffic direction (i.e., for compression and/or encryption). This command takes a struct ng_mppc_config as an argument: /* Length of MPPE key */ #define MPPE_KEY_LEN 16 /* MPPC/MPPE PPP negotiation bits */ #define MPPC_BIT 0x00000001 /* mppc compression bits */ #define MPPE_40 0x00000020 /* use 40 bit key */ #define MPPE_56 0x00000080 /* use 56 bit key */ #define MPPE_128 0x00000040 /* use 128 bit key */ #define MPPE_BITS 0x000000e0 /* mppe encryption bits */ #define MPPE_STATELESS 0x01000000 /* use stateless mode */ #define MPPC_VALID_BITS 0x010000e1 /* possibly valid bits */ /* Configuration for a session */ struct ng_mppc_config { u_char enable; /* enable */ u_int32_t bits; /* config bits */ u_char startkey[MPPE_KEY_LEN]; /* start key */ }; The enabled field enables traffic flow through the node. The bits field contains the bits as negotiated by the Compression Control Pro- tocol (CCP) in PPP. The startkey is only necessary if MPPE was negotiated, and must be equal to the session start key as defined for MPPE. This key is based on the MS-CHAP credentials used at link authentication time. NGM_MPPC_CONFIG_DECOMP This command resets and configures the node for a session in the incoming traffic direction (i.e., for decompression and/or decryption). This command takes a struct ng_mppc_config as an argument. NGM_MPPC_RESETREQ This message contains no arguments, and is bi-directional. If an error is detected during decompression, this message is sent by the node to the originator of the NGM_MPPC_CONFIG_DECOMP message that initiated the session. The receiver should respond by sending a PPP CCP Reset-Request to the peer. This message may also be received by this node type when a CCP Reset-Request is received by the local PPP entity. The node will respond by flushing its outgoing compression and encryption state so the remote side can resynchronize. SHUTDOWN
This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when both hooks have been disconnected. COMPILATION
The kernel options NETGRAPH_MPPC_COMPRESSION and NETGRAPH_MPPC_ENCRYPTION are supplied to selectively compile in either or both capabilities. At least one of these must be defined, or else this node type is useless. The MPPC protocol requires proprietary compression code available from Hi/Fn (formerly STAC). These files must be obtained elsewhere and added to the kernel sources before this node type will compile with the NETGRAPH_MPPC_COMPRESSION option. SEE ALSO
netgraph(4), ng_ppp(4), ngctl(8) G. Pall, Microsoft Point-To-Point Compression (MPPC) Protocol, RFC 2118. G. S. Pall and G. Zorn, Microsoft Point-To-Point Encryption (MPPE) Protocol, draft-ietf-pppext-mppe-04.txt. K. Hamzeh, G. Pall, W. Verthein, J. Taarud, W. Little, and G. Zorn, Point-to-Point Tunneling Protocol (PPTP), RFC 2637. AUTHORS
Archie Cobbs <archie@FreeBSD.org> BUGS
In PPP, encryption should be handled by the Encryption Control Protocol (ECP) rather than CCP. However, Microsoft combined both compression and encryption into their ``compression'' algorithm, which is confusing. BSD
December 8, 1999 BSD
Man Page