diff -aur a/debian/include/linux/netfilter_ipv4/ipt_ULOG.h b/debian/include/linux/netfilter_ipv4/ipt_ULOG.h
--- a/debian/include/linux/netfilter_ipv4/ipt_ULOG.h	2010-04-08 22:18:47.000000000 +0100
+++ b/debian/include/linux/netfilter_ipv4/ipt_ULOG.h	2010-04-08 22:25:50.000000000 +0100
@@ -31,15 +31,28 @@
 	char prefix[ULOG_PREFIX_LEN];
 };
 
+/* This is needed to fix the mismatch between the field sizes in kernel
+ * and userspace. In particular, Debian sparc port features 32-bit
+ * userspace, but 64-bit kernel, leading to size mismatch. Structure
+ * above is not used anywhere in ulogd, otherwise it would need to be
+ * similarly mangled. */
+#ifdef __sparc__
+#define KERNEL_LONG long long
+#define KERNEL_SIZE_T unsigned long long
+#else
+#define KERNEL_LONG long
+#define KERNEL_SIZE_T size_t
+#endif
+
 /* Format of the ULOG packets passed through netlink */
 typedef struct ulog_packet_msg {
-	unsigned long mark;
-	long timestamp_sec;
-	long timestamp_usec;
+	unsigned KERNEL_LONG mark;
+	KERNEL_LONG timestamp_sec;
+	KERNEL_LONG timestamp_usec;
 	unsigned int hook;
 	char indev_name[IFNAMSIZ];
 	char outdev_name[IFNAMSIZ];
-	size_t data_len;
+	KERNEL_SIZE_T data_len;
 	char prefix[ULOG_PREFIX_LEN];
 	unsigned char mac_len;
 	unsigned char mac[ULOG_MAC_LEN];
diff -aur a/debian/patches/ipt_ULOG.patch b/debian/patches/ipt_ULOG.patch
--- a/debian/patches/ipt_ULOG.patch	2010-04-08 22:18:47.000000000 +0100
+++ b/debian/patches/ipt_ULOG.patch	2010-04-08 22:19:26.000000000 +0100
@@ -5,7 +5,7 @@
  # doesn't work for subdirs
  #CFLAGS+=$(INCIPULOG) $(INCCONFFILE)
 -CFLAGS+=-I/lib/modules/`uname -r`/build/include
-+CFLAGS+=-I@srcdir@/debian/include
++CFLAGS+=-I$(PWD)/debian/include
  #CFLAGS+=@DEFS@
  #CFLAGS+=-g -DDEBUG -DDEBUG_MYSQL -DDEBUG_PGSQL
  
diff -aur a/extensions/ulogd_BASE.c b/extensions/ulogd_BASE.c
--- a/extensions/ulogd_BASE.c	2005-11-25 19:58:26.000000000 +0000
+++ b/extensions/ulogd_BASE.c	2010-04-08 22:18:35.000000000 +0100
@@ -203,7 +203,13 @@
 				ulog_packet_msg_t *pkt)
 {
 	ulog_iret_t *ret = ip->result;
+#ifdef STRICT_ALIGNMENT
+	struct iphdr aligned_iph;
+	memcpy(&aligned_iph, pkt->payload, sizeof(struct iphdr));
+	struct iphdr *iph = &aligned_iph;
+#else
 	struct iphdr *iph = (struct iphdr *) pkt->payload;
+#endif
 
 	ret[0].value.ui32 = ntohl(iph->saddr);
 	ret[0].flags |= ULOGD_RETF_VALID;
@@ -308,7 +314,13 @@
 {
 	struct iphdr *iph = (struct iphdr *) pkt->payload;
 	void *protoh = (u_int32_t *)iph + iph->ihl;
+#ifdef STRICT_ALIGNMENT
+	struct tcphdr aligned_tcph;
+	memcpy(&aligned_tcph, protoh, sizeof(struct tcphdr));
+	struct tcphdr *tcph = &aligned_tcph;
+#else
 	struct tcphdr *tcph = (struct tcphdr *) protoh;
+#endif
 	ulog_iret_t *ret = ip->result;
 
 	if (iph->protocol != IPPROTO_TCP)
@@ -382,7 +394,13 @@
 {
 	struct iphdr *iph = (struct iphdr *) pkt->payload;
 	void *protoh = (u_int32_t *)iph + iph->ihl;
-	struct udphdr *udph = protoh;
+#ifdef STRICT_ALIGNMENT
+	struct udphdr aligned_udph;
+	memcpy(&aligned_udph, protoh, sizeof(struct udphdr));
+	struct udphdr *udph = &aligned_udph;
+#else
+	struct udphdr *udph = (struct udphdr *) protoh;
+#endif
 	ulog_iret_t *ret = ip->result;
 
 	if (iph->protocol != IPPROTO_UDP)
@@ -440,7 +458,13 @@
 {
 	struct iphdr *iph = (struct iphdr *) pkt->payload;
 	void *protoh = (u_int32_t *)iph + iph->ihl;
-	struct icmphdr *icmph = protoh;
+#ifdef STRICT_ALIGNMENT
+	struct icmphdr aligned_icmph;
+	memcpy(&aligned_icmph, protoh, sizeof(struct icmphdr));
+	struct icmphdr *icmph = &aligned_icmph;
+#else
+	struct icmphdr *icmph = (struct icmphdr *) protoh;
+#endif
 	ulog_iret_t *ret = ip->result;
 
 	if (iph->protocol != IPPROTO_ICMP)
diff -aur a/extensions/ulogd_PWSNIFF.c b/extensions/ulogd_PWSNIFF.c
--- a/extensions/ulogd_PWSNIFF.c	2005-11-25 19:58:26.000000000 +0000
+++ b/extensions/ulogd_PWSNIFF.c	2010-04-08 22:16:43.000000000 +0100
@@ -64,7 +64,13 @@
 
 static ulog_iret_t *_interp_pwsniff(ulog_interpreter_t *ip, ulog_packet_msg_t *pkt)
 {
+#ifdef STRICT_ALIGNMENT
+	char aligned_payload[sizeof(struct iphdr) + sizeof(struct tcphdr)];
+	memcpy(aligned_payload, pkt->payload, sizeof(struct iphdr) + sizeof(struct tcphdr));
+	struct iphdr *iph = (struct iphdr *) aligned_payload;
+#else
 	struct iphdr *iph = (struct iphdr *) pkt->payload;
+#endif
 	void *protoh = (u_int32_t *)iph + iph->ihl;
 	struct tcphdr *tcph = protoh;
 	u_int32_t tcplen = ntohs(iph->tot_len) - iph->ihl * 4;
diff -aur a/include/ulogd/ulogd.h b/include/ulogd/ulogd.h
--- a/include/ulogd/ulogd.h	2005-11-25 19:58:25.000000000 +0000
+++ b/include/ulogd/ulogd.h	2010-04-08 21:49:22.000000000 +0100
@@ -56,6 +56,12 @@
 #define ULOGD_ERROR	7	/* error condition, requires user action */
 #define ULOGD_FATAL	8	/* fatal, program aborted */
 
+
+/* whether the platform has strict alignment requirements */
+#ifdef __sparc__
+#define STRICT_ALIGNMENT
+#endif
+
 typedef struct ulog_iret {
 	/* next interpreter return (key) in the global list */
 	struct ulog_iret *next;