Build on Jeff Roberson's linker-set based dynamic per-CPU allocator

(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)

1 files changed, 27 insertions, 11 deletions

diff --git a/sys/netinet/ip_var.h b/sys/netinet/ip_var.h
index c0b02eb1ea19..0db34d28d6b1 100644
--- a/sys/netinet/ip_var.h
+++ b/sys/netinet/ip_var.h
@@ -129,6 +129,8 @@ struct	ipstat {
 
 #ifdef _KERNEL
 
+#include <net/vnet.h>
+
 #define	IPSTAT_ADD(name, val)	V_ipstat.name += (val)
 #define	IPSTAT_SUB(name, val)	V_ipstat.name -= (val)
 #define	IPSTAT_INC(name)	IPSTAT_ADD(name, 1)
@@ -158,19 +160,27 @@ struct inpcb;
 struct route;
 struct sockopt;
 
-#ifdef VIMAGE_GLOBALS
-extern struct	ipstat	ipstat;
-extern u_short	ip_id;			/* ip packet ctr, for ids */
-extern int	ip_do_randomid;
-extern int	ip_defttl;		/* default IP ttl */
-extern int	ipforwarding;		/* ip forwarding */
+VNET_DECLARE(struct ipstat, ipstat);
+VNET_DECLARE(u_short, ip_id);			/* ip packet ctr, for ids */
+VNET_DECLARE(int, ip_defttl);			/* default IP ttl */
+VNET_DECLARE(int, ipforwarding);		/* ip forwarding */
+#ifdef IPSTEALTH
+VNET_DECLARE(int, ipstealth);			/* stealth forwarding */
+#endif
+VNET_DECLARE(int, rsvp_on);
+VNET_DECLARE(struct socket *, ip_rsvpd);	/* reservation protocol daemon*/
+VNET_DECLARE(struct socket *, ip_mrouter);	/* multicast routing daemon */
+
+#define	V_ipstat		VNET_GET(ipstat)
+#define	V_ip_id			VNET_GET(ip_id)
+#define	V_ip_defttl		VNET_GET(ip_defttl)
+#define	V_ipforwarding		VNET_GET(ipforwarding)
 #ifdef IPSTEALTH
-extern int	ipstealth;		/* stealth forwarding */
+#define	V_ipstealth		VNET_GET(ipstealth)
 #endif
-extern int rsvp_on;
-extern struct socket *ip_rsvpd;		/* reservation protocol daemon */
-extern struct socket *ip_mrouter;	/* multicast routing daemon */
-#endif /* VIMAGE_GLOBALS */
+#define	V_rsvp_on		VNET_GET(rsvp_on)
+#define	V_ip_rsvpd		VNET_GET(ip_rsvpd)
+#define	V_ip_mrouter		VNET_GET(ip_mrouter)
 
 extern u_char	ip_protox[];
 extern int	(*legal_vif_num)(int);
@@ -231,6 +241,12 @@ extern int	(*ip_fw_ctl_ptr)(struct sockopt *);
 extern int	(*ip_dn_ctl_ptr)(struct sockopt *);
 extern int	(*ip_dn_io_ptr)(struct mbuf **m, int dir, struct ip_fw_args *fwa);
 extern void	(*ip_dn_ruledel_ptr)(void *);		/* in ip_fw2.c */
+
+VNET_DECLARE(int, ip_do_randomid);
+#define	V_ip_do_randomid	VNET_GET(ip_do_randomid)
+#define	ip_newid()	((V_ip_do_randomid != 0) ? ip_randomid() : \
+			    htons(V_ip_id++))
+
 #endif /* _KERNEL */
 
 #endif /* !_NETINET_IP_VAR_H_ */