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Support for dynamically loadable and unloadable IP protocols in the ipmux.

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With pr_proto_register() it has become possible to dynamically load protocols
within the PF_INET domain.  However the PF_INET domain has a second important
structure called ip_protox[] that is derived from the 'struct protosw inetsw[]'
and takes care of the de-multiplexing of the various protocols that ride on
top of IP packets.

The functions ipproto_[un]register() allow to dynamically adjust the ip_protox[]
array mux in a consistent and easy way.  To register a protocol within
ip_protox[] the existence of a corresponding and matching protocol definition
in inetsw[] is required.  The function does not allow to overwrite an already
registered protocol.  The unregister function simply replaces the mux slot with
the default index pointer to IPPROTO_RAW as it was previously.
This commit is contained in:
Andre Oppermann 2004-10-19 15:45:57 +00:00
parent 33bab57d1e
commit de38924dc0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=136694
2 changed files with 64 additions and 1 deletions
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63
sys/netinet/ip_input.c
View File

@ -261,7 +261,7 @@ ip_init()
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
/* Be careful to only index valid IP protocols. */
if (pr->pr_protocol && pr->pr_protocol < IPPROTO_MAX)
if (pr->pr_protocol <= IPPROTO_MAX)
ip_protox[pr->pr_protocol] = pr - inetsw;
}
@ -1144,6 +1144,67 @@ ip_drain()
in_rtqdrain();
}
/*
* The protocol to be inserted into ip_protox[] must be already registered
* in inetsw[], either statically or through pf_proto_register().
*/
int
ipproto_register(u_char ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto == 0)
return (EPROTONOSUPPORT);
/*
* The protocol slot must not be occupied by another protocol
* already. An index pointing to IPPROTO_RAW is unused.
*/
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
return (EEXIST);
/* Find the protocol position in inetsw[] and set the index. */
for (pr = inetdomain.dom_protosw;
pr < inetdomain.dom_protoswNPROTOSW; pr++) {
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol == ipproto) {
/* Be careful to only index valid IP protocols. */
if (pr->pr_protocol <= IPPROTO_MAX) {
ip_protox[pr->pr_protocol] = pr - inetsw;
return (0);
} else
return (EINVAL);
}
}
return (EPROTONOSUPPORT);
}
int
ipproto_unregister(u_char ipproto)
{
struct protosw *pr;
/* Sanity checks. */
if (ipproto == 0)
return (EPROTONOSUPPORT);
/* Check if the protocol was indeed registered. */
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
return (EPFNOSUPPORT);
if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
return (ENOENT);
/* Reset the protocol slot to IPPROTO_RAW. */
ip_protox[ipproto] = pr - inetsw;
return (0);
}
/*
* Do option processing on a datagram,
* possibly discarding it if bad options are encountered,

2
sys/netinet/ip_var.h
View File

@ -168,6 +168,8 @@ extern int (*ip_mforward)(struct ip *, struct ifnet *, struct mbuf *,
int ip_output(struct mbuf *,
struct mbuf *, struct route *, int, struct ip_moptions *,
struct inpcb *);
int ipproto_register(u_char);
int ipproto_unregister(u_char);
struct mbuf *
ip_reass(struct mbuf *);
struct in_ifaddr *