Index: sys/net/if_pflog.h
===================================================================
--- sys/net/if_pflog.h
+++ sys/net/if_pflog.h
@@ -31,6 +31,8 @@
 #ifndef _NET_IF_PFLOG_H_
 #define	_NET_IF_PFLOG_H_
 
+#include <net/bpf.h>
+
 #define	PFLOGIFS_MAX	16
 
 #define	PFLOG_RULESET_NAME_SIZE	16
@@ -51,11 +53,13 @@
 	u_int8_t	dir;
 	u_int8_t	pad[3];
 	u_int32_t	ridentifier;
+	u_int8_t	reserve;	/* Appease broken software like Wireshark. */
+	u_int8_t	pad2[3];
 };
 
-#define	PFLOG_HDRLEN		sizeof(struct pfloghdr)
+#define	PFLOG_HDRLEN		BPF_WORDALIGN(offsetof(struct pfloghdr, pad2))
 /* minus pad, also used as a signature */
-#define	PFLOG_REAL_HDRLEN	offsetof(struct pfloghdr, pad)
+#define	PFLOG_REAL_HDRLEN	offsetof(struct pfloghdr, pad2)
 
 #ifdef _KERNEL
 struct pf_rule;
Index: sys/netpfil/pf/if_pflog.c
===================================================================
--- sys/netpfil/pf/if_pflog.c
+++ sys/netpfil/pf/if_pflog.c
@@ -215,7 +215,7 @@
 		return (0);
 
 	bzero(&hdr, sizeof(hdr));
-	hdr.length = PFLOG_HDRLEN;
+	hdr.length = PFLOG_REAL_HDRLEN;
 	hdr.af = af;
 	hdr.action = rm->action;
 	hdr.reason = reason;