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net_add_domain, pfctlinput, pfctlinput2, pffindproto, pffindtype,

 

NAME

      net_add_domain, pfctlinput, pfctlinput2, pffindproto, pffindtype,
      DOMAIN_SET - network domain management
 

SYNOPSIS

      #include <sys/param.h>
      #include <sys/kernel.h>
      #include <sys/protosw.h>
      #include <sys/domain.h>
 
      void
      net_add_domain(void *data);
 
      void
      pfctlinput(int cmd, struct sockaddr *sa);
 
      void
      pfctlinput2(int cmd, struct sockaddr *sa, void *ctlparam);
 
      struct protosw *
      pffindproto(int family, int protocol, int type);
 
      struct protosw *
      pffindtype(int family, int type);
 
      void
      DOMAIN_SET(name);
 

DESCRIPTION

      Network protocols installed in the system are maintained within what are
      called domains (for example the inetdomain and localdomain).
 
      struct domain {
              int     dom_family;             /* AF_xxx */
              char    *dom_name;
              void    (*dom_init)             /* initialize domain data structures */
                      (void);
              int     (*dom_externalize)      /* externalize access rights */
                      (struct mbuf *, struct mbuf **);
              void    (*dom_dispose)          /* dispose of internalized rights */
                      (struct mbuf *);
              struct  protosw *dom_protosw, *dom_protoswNPROTOSW;
              struct  domain *dom_next;
              int     (*dom_rtattach)         /* initialize routing table */
                      (void **, int);
              int     dom_rtoffset;           /* an arg to rtattach, in bits */
              int     dom_maxrtkey;           /* for routing layer */
      };
 
      Each domain contains an array of protocol switch structures (struct
      protosw *), one for each socket type supported.
 
      struct protosw {
              short   pr_type;                /* socket type used for */
              struct  domain *pr_domain;      /* domain protocol a member of */
              short   pr_protocol;            /* protocol number */
              short   pr_flags;               /* see below */
      /* protocol-protocol hooks */
              pr_input_t *pr_input;           /* input to protocol (from below) */
              pr_output_t *pr_output;         /* output to protocol (from above) */
              pr_ctlinput_t *pr_ctlinput;     /* control input (from below) */
              pr_ctloutput_t *pr_ctloutput;   /* control output (from above) */
      /* user-protocol hook */
              pr_usrreq_t     *pr_ousrreq;
      /* utility hooks */
              pr_init_t *pr_init;
              pr_fasttimo_t *pr_fasttimo;     /* fast timeout (200ms) */
              pr_slowtimo_t *pr_slowtimo;     /* slow timeout (500ms) */
              pr_drain_t *pr_drain;           /* flush any excess space possible */
 
              struct  pr_usrreqs *pr_usrreqs; /* supersedes pr_usrreq() */
              struct  pfil_head       pr_pfh;
      };
 
      The following functions handle the registration of a new domain, lookups
      of specific protocols and protocol types within those domains, and handle
      control messages from the system.
 
      pfctlinput() is called by the system whenever an event occurs that could
      affect every domain.  Examples of those types of events are routing table
      changes, interface shutdowns or certain ICMP message types.  When called,
      pfctlinput() calls the protocol specific pr_ctlinput() function for each
      protocol in that has defined one, in every domain.
 
      pfctlinput2() provides that same functionality of pfctlinput(), but with
      a few additional checks and a new void * argument that is passed directly
      to the protocol’s pr_ctlinput() function.  Unlike pfctlinput(),
      pfctlinput2() verifies that sa is not NULL, and that only the protocol
      families that are the same as sa have their pr_ctlinput() function
      called.
 
      net_add_domain() adds a new protocol domain to the system.  The argument
      data is cast directly to struct domain * within the function, but is
      declared void * in order to prevent compiler warnings when new domains
      are registered with SYSINIT().  In most cases net_add_domain() is not
      called directly, instead DOMAIN_SET() is used.
 
      If the new domain has defined an initialization routine, it is called by
      net_add_domain(); as well, each of the protocols within the domain that
      have defined an initialization routine will have theirs called.
 
      Once a domain is added it cannot be unloaded.  This is because there is
      no reference counting system in place to determine if there are any
      active references from sockets within that domain.
 
      pffindtype() and pffindproto() look up a protocol by its number or by its
      type.  In most cases, if the protocol or type cannot be found, NULL is
      returned, but pffindproto() may return the default if the requested type
      is SOCK_RAW, a protocol switch type of SOCK_RAW is found, and the domain
      has a default raw protocol.
 
      Both functions are called by socreate() in order to resolve the protocol
      for the socket currently being created.
 
      DOMAIN_SET() is a macro that simplifies the registration of a domain via
      SYSINIT().  The code resulting from the macro expects there to be a
      domain structure named “namedomain” where name is the argument to
      DOMAIN_SET():
 
      struct domain localdomain =
      { AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose,
        localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] };
 
      DOMAIN_SET(local);
      Both pffindtype() and pffindproto() return a struct protosw * for the
      protocol requested.  If the protocol or socket type is not found, NULL is
      returned.  In the case of pffindproto(), the default protocol may be
      returned for SOCK_RAW types if the domain has a default raw protocol.
      socket(2)
 

AUTHORS

      This manual page was written by Chad David 〈davidc@acns.ab.ca〉.
 

Sections

Based on BSD UNIX
FreeBSD is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. Additional platforms are in various stages of development.