net_add_domain pfctlinput pfctlinput2 pffindproto pffindtype DOMAIN_SET - network domain management
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 (Vt 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
Vt void *
argument that is passed directly to the protocol's
pr_ctlinput ();
function.
Unlike
pfctlinput (,);
pfctlinput2 ();
verifies that
Fa sa
is not
NULL
and that only the protocol families that are the same as
Fa sa
have their
pr_ctlinput ();
function called.
net_add_domain ();
adds a new protocol domain to the system.
The argument
Fa data
is cast directly to
Vt struct domain *
within the function, but is declared
Vt 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
``Fa name domain
''
where
Fa 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);
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