Summer of Code 2005: improve libalias - part 1 of 2

With the first part of my previous Summer of Code work, we get:

-made libalias modular:

 -support for 'particular' protocols (like ftp/irc/etcetc) is no more
  hardcoded inside libalias, but it's available through external
  modules loadable at runtime

 -modules are available both in kernel (/boot/kernel/alias_*.ko) and
  user land (/lib/libalias_*)

 -protocols/applications modularized are: cuseeme, ftp, irc, nbt, pptp,
  skinny and smedia

-added logging support for kernel side

-cleanup

After a buildworld, do a 'mergemaster -i' to install the file libalias.conf
in /etc or manually copy it.

During startup (and after every HUP signal) user land applications running
the new libalias will try to read a file in /etc called libalias.conf:
that file contains the list of modules to load.

User land applications affected by this commit are ppp and natd:
if libalias.conf is present in /etc you won't notice any difference.

The only kernel land bit affected by this commit is ng_nat:
if you are using ng_nat, and it doesn't correctly handle
ftp/irc/etcetc sessions anymore, remember to kldload
the correspondent module (i.e. kldload alias_ftp).

General information and details about the inner working are available
in the libalias man page under the section 'MODULAR ARCHITECTURE
(AND ipfw(4) SUPPORT)'.

NOTA BENE: this commit affects _ONLY_ libalias, ipfw in-kernel nat
support will be part of the next libalias-related commit.

Approved by: glebius
Reviewed by: glebius, ru

1 files changed, 10 insertions, 4 deletions

diff --git a/sys/netinet/libalias/alias.h b/sys/netinet/libalias/alias.h
index 2c50943..4a809f4 100644
--- a/sys/netinet/libalias/alias.h
+++ b/sys/netinet/libalias/alias.h
@@ -28,7 +28,7 @@
  * $FreeBSD$
  */
 
-/*-
+/*
  * Alias.h defines the outside world interfaces for the packet aliasing
  * software.
  *
@@ -39,12 +39,16 @@
 #ifndef _ALIAS_H_
 #define	_ALIAS_H_
 
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+
+#define LIBALIAS_BUF_SIZE 128
 #ifdef	_KERNEL
 /*
  * The kernel version of libalias does not support these features.
  */
 #define	NO_FW_PUNCH
-#define	NO_LOGGING
 #define	NO_USE_SOCKETS
 #endif
 
@@ -180,6 +184,10 @@ void		LibAliasSetTarget(struct libalias *, struct in_addr _target_addr);
 /* Transparent proxying routines. */
 int		LibAliasProxyRule(struct libalias *, const char *_cmd);
 
+/* Module handling API */
+int             LibAliasLoadModule(char *);
+int             LibAliasUnLoadAllModule(void);
+int             LibAliasRefreshModules(void);
 
 /*
  * Mode flags and other constants.
@@ -192,9 +200,7 @@ int		LibAliasProxyRule(struct libalias *, const char *_cmd);
  * If PKT_ALIAS_LOG is set, a message will be printed to /var/log/alias.log
  * every time a link is created or deleted.  This is useful for debugging.
  */
-#ifndef	NO_LOGGING
 #define	PKT_ALIAS_LOG			0x01
-#endif
 
 /*
  * If PKT_ALIAS_DENY_INCOMING is set, then incoming connections (e.g. to ftp,