M1 progress: engine port compiles except pf.c; AF_DIVERT socket family; ifq framework

- compat layer extended through the full BSD API surface pf_ioctl/pf_lb/
  pf_if/pf_norm/pf_table/pf_ruleset/radix/md5/sha2 need (all compile):
  cpumem/counters model, ifaddr/ifg groups, cred view, endian+in6 names,
  NAT46/64, SipHash24, mbuf_list, frag6 helpers, ip6 forward/checksum,
  tcp options/FSM names, taskqueue & sysctl shims (documented in
  docs/porting-notes.md)
- pfsrc/divert_sock.c: real BSD divert(4) as runtime-registered PF_DIVERT=32
  socket family inside the module (sock_register; NPROTO=AF_MAX=45 -> zero
  core patches); divert_packet/divert6_packet wired for pf.c
- compat/pfk_ifq.c: OpenBSD 8.0 ifq framework with priq back end; hfsc and
  fq_codel aliases pending M5 (recorded in feature matrix as pending)
- design + plan updated for the divert decision (user-requested)
- stage-port.sh: single deterministic rename program for headers and .c

module/include/compat/net/if_var.h

@@ -1,5 +1,48 @@
-/* PFLINUX compat: <net/if_var.h> — ifnet view comes from pfk_if.h */
+/* PFLINUX compat: <net/if_var.h> — the ifnet view comes from pfk_if.h;
+ * the BSD interface-group types are reproduced here (they need the BSD
+ * queue macros and the refcnt type). */
 #ifndef _PFK_IF_VAR_H
 #define _PFK_IF_VAR_H
-/* intentionally minimal; struct pfk_ifnet is the ifnet */
+
+#include "compat/sys/queue.h"
+#include "compat/sys/refcnt.h"
+
+struct ifg_member {
+	TAILQ_ENTRY(ifg_member)	 ifgm_next;	/* [N] all members are chained */
+	struct pfk_ifnet	*ifgm_ifp;	/* [I] member interface */
+};
+
+struct ifg_group {
+	char			 ifg_group[IFNAMSIZ];
+	u_int			 ifg_refcnt;
+	caddr_t			 ifg_pf_kif;
+	int			 ifg_carp_demoted;
+	TAILQ_HEAD(, ifg_member)	 ifg_members;
+	TAILQ_ENTRY(ifg_group)	 ifg_next;
+	struct refcnt		 ifg_tmprefcnt;
+	TAILQ_ENTRY(ifg_group)	 ifg_tmplist;
+};
+
+/* BSD struct ifaddr (net/if_var.h) — the ported PF code walks interface
+ * addresses through this type. */
+struct pfk_ifnet;
+
+struct ifaddr {
+	struct sockaddr	*ifa_addr;	/* address of interface */
+	struct sockaddr	*ifa_dstaddr;	/* other end of p-to-p link */
+#define	ifa_broadaddr	ifa_dstaddr
+	struct sockaddr	*ifa_netmask;	/* used to determine subnet */
+	struct pfk_ifnet	*ifa_ifp;	/* back-pointer to interface */
+	TAILQ_ENTRY(ifaddr) ifa_list;	/* [N] list of addresses */
+	TAILQ_ENTRY(ifaddr) ifa_tmplist;/* [T] temporary list */
+	u_int		 ifa_flags;
+	struct refcnt	 ifa_refcnt;
+	int		 ifa_metric;
+};
+
+struct ifg_list {
+	struct ifg_group	*ifgl_group;	/* [I] interface group */
+	TAILQ_ENTRY(ifg_list)	 ifgl_next;	/* [N] all groups are chained */
+};
+
 #endif