PIPEX(4)

NAME
pipex - PPP IP EXtension to handle IP/PPP frames in-kernel

SYNOPSIS
option PIPEX

#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/pipex.h>

DESCRIPTION
pipex is used with tun(4) and pppx, and handles PPP frames and forwards IP packets in-kernel. It accelerates the performance of packet forwarding, because it reduces copying of packets between kernel and userland. pipex is disabled by default. To enable it, set net.pipex.enable to ‘1’ using sysctl(8).

pipex adds some extensions to the ioctl(2) requests to tun(4) or pppx devices. The added requests are as follows:

PIPEXGMODE int *
    Get the devices's pipex operation mode. 1 to enable pipex on this device; 0 to disable.

PIPEXSMODE int *
    Set the device's pipex operation mode. 1 to enable pipex on this device; 0 to disable.

PIPEXASESSION struct pipex_session_req *
    Add a new PPP session to be handled by pipex. The status of the session is passed as a pipex_session_req structure. The pipex_session_req structure has the following definition:

        struct pipex_session_req {
            int         pr_protocol;         /* tunnel protocol  */
        #define PIPEX_PROTO_L2TP   1         /* protocol L2TP */
        #define PIPEX_PROTO_PPTP   2         /* protocol PPTP */
        #define PIPEX_PROTO_PPPOE  3         /* protocol PPPoE */
            uint16_t    pr_session_id;       /* session-id */
            uint16_t    pr_peer_session_id;  /* peer's session-id */
            uint32_t    pr_ppp_flags;        /* ppp configuration flags */
        #define PIPEX_PPP_ACFC_ACCEPTED  0x0001 /* ACFC accepted */
        #define PIPEX_PPP_PFC_ACCEPTED   0x0002 /* PFC accepted */
        #define PIPEX_PPP_ACFC_ENABLED   0x0004 /* ACFC enabled */
        #define PIPEX_PPP_PFC_ENABLED    0x0008 /* PFC enabled */
        #define PIPEX_PPP_MPPE_ACCEPTED  0x0010 /* MPPE accepted */
        #define PIPEX_PPP_MPPE_ENABLED   0x0020 /* MPPE enabled */
        #define PIPEX_PPP_MPPE_REQUIRED  0x0040 /* MPPE is required */
        #define PIPEX_PPP_HAS_ACF        0x0080 /* has ACF */
        #define PIPEX_PPP_ADJUST_TCPMSS  0x0100 /* do tcpmss adjustment */
        #define PIPEX_PPP_INGRESS_FILTER 0x0200 /* do ingress filter */
            int8_t      pr_ccp_id;           /* ccp current packet id */
            int         pr_ppp_id;           /* ppp id. */
            uint16_t    pr_peer_mru;         /* peer's mru */
            uint16_t    pr_timeout_sec;      /* idle timer */
            struct in_addr      pr_ip_srcaddr;    /* local IP address.
        					     not used by tun(4) */
            struct in_addr      pr_ip_address;    /* framed IP address */
            struct in_addr      pr_ip_netmask;    /* framed IP netmask */
            struct sockaddr_in6 pr_ip6_address;   /* framed IPv6 address */
            int                 pr_ip6_prefixlen; /* framed IPv6 prefix
                                                     length */
            union {
                struct {
                    uint32_t snd_nxt;         /* send next */
                    uint32_t rcv_nxt;         /* receive next */
                    uint32_t snd_una;         /* unacked */
                    uint32_t rcv_acked;       /* recv acked */
                    int winsz;                /* window size */
                    int maxwinsz;             /* max window size */
                    int peer_maxwinsz;        /* peer's max window size */
                } pptp;
                struct {
                    /* select protocol options: 1 for enable */
                    uint32_t option_flags;
            #define PIPEX_L2TP_USE_SEQUENCING  0x00000001
                                              /* use sequence number
        					 on L2TP data messages */
                    uint16_t tunnel_id;       /* our tunnel-id */
                    uint16_t peer_tunnel_id;  /* peer's tunnel-id */
                    uint32_t ns_nxt;          /* send next */
                    uint32_t nr_nxt;          /* receive next */
                    uint32_t ns_una;          /* unacked */
                    uint32_t nr_acked;        /* recv acked */
                    uint32_t ipsecflowinfo;   /* IPsec flow id for NAT-T */
                } l2tp;
                struct {
                    char over_ifname[IF_NAMESIZE];
                                              /* ethernet ifname */
                } pppoe;
            } pr_proto;
            struct sockaddr_storage  pr_peer_address;
                                              /* peer address of tunnel */
            struct sockaddr_storage  pr_local_address;
        				      /* our address of tunnel */
            struct pipex_mppe_req    pr_mppe_recv;
        				      /* mppe key for receive */
            struct pipex_mppe_req    pr_mppe_send;
        				      /* mppe key for send */
        };

    The pipex_mppe_req structure that was used by pr_mppe_recv and pr_mppe_send has the following definition:

        struct pipex_mppe_req {
            int16_t  stateless;            /* mppe key mode.
                                              1 for stateless */
            int16_t  keylenbits;           /* mppe key length(in bits)*/
            u_char   master_key[PIPEX_MPPE_KEYLEN];
                                           /* mppe mastter key */
        };

PIPEXDSESSION struct pipex_session_close_req *
    Delete the specified session from the kernel. Specify the session using a pipex_session_stat_req structure, which has the following definition:

        struct pipex_session_stat_req {
            int                      psr_protocol;   /* tunnel protocol */
            uint16_t                 psr_session_id; /* session-id */
            struct pipex_statistics  psr_stat;       /* statistics */
        };

    The psr_protocol and psr_session_id fields used to specify the session are mandatory. On successful return, the psr_stat field is filled by the kernel. See PIPEXGSTAT section for a description of the pipex_statistics structure.

PIPEXCSESSION struct pipex_session_config_req *
    Change the configuration of the specified session. The session and configuration are specified by a pipex_session_config_req structure, which has the following definition:

        struct pipex_session_config_req {
            int       pcr_protocol;           /* tunnel protocol  */
            uint16_t  pcr_session_id;         /* session-id */
            int       pcr_ip_forward;         /* ip_forwarding on/off */
        };

PIPEXGSTAT struct pipex_session_stat_req *
    Get statistics for the specified session. Specify the session using a pipex_session_stat_req structure, which has the following definition:

        struct pipex_session_stat_req {
            int                      psr_protocol;   /* tunnel protocol */
            uint16_t                 psr_session_id; /* session-id */
            struct pipex_statistics  psr_stat;       /* statistics */
        };

    The psr_protocol and psr_session_id fields used to specify the session are mandoatory. On successful return, the psr_stat field is filled by the kernel. The pipex_statistics structure has the following definition:

        struct pipex_statistics {
            uint32_t ipackets;   /* packets received from tunnel */
            uint32_t ierrors;    /* error packets received from tunnel */
            uint64_t ibytes;     /* number of received bytes from tunnel */
            uint32_t opackets;   /* packets sent to tunnel */
            uint32_t oerrors;    /* error packets on sending to tunnel */
            uint64_t obytes;     /* number of sent bytes to tunnel */
            uint32_t idle_time;  /* idle time in seconds */
        };

PIPEXGCLOSED struct pipex_session_list_req *
    Get a list of closed sessions. pipex reserves closed sessions for 30 seconds for userland programs to get statistical information. On successful return, the pipex_session_list_req structure is filled by the kernel. The structure has the following definition.

        struct pipex_session_list_req {
            uint8_t  plr_flags;
        #define PIPEX_LISTREQ_MORE         0x01      /* has more session */
            int      plr_ppp_id_count;               /* count of PPP id */
            int      plr_ppp_id[PIPEX_MAX_LISTREQ];  /* PPP id */
        };

PIPEXSIFDESCR struct pipex_session_descr_req *
    Set the pppx interface's description of the session. This command doesn't work on tun(4) devices. Specify the session and its description using a pipex_session_descr_req structure, which has the following definition:

        struct pipex_session_descr_req {
            int       pdr_protocol;           /* tunnel protocol */
            uint16_t  pdr_session_id;         /* session-id */
            char      pdr_descr[IFDESCRSIZE]; /* description */
        };

SEE ALSO
ioctl(2), pppx(4), tun(4), npppd(8), sysctl(8)

AUTHORS
The pipex was written by Internet Initiative Japan Inc.