diff --git a/Makefile b/Makefile
index 151fa9d..cdc1202 100644
--- a/Makefile
+++ b/Makefile
@@ -331,7 +331,7 @@ WARNINGS += -Wundef
 WARNINGS += -Wvolatile-register-var
 WARNINGS += -Wwrite-strings
 
-CFLAGS	+= $(WARNINGS)
+CFLAGS	+= $(WARNINGS) -DCONFIG_HAS_AIO
 
 ifneq ($(WERROR),0)
 	CFLAGS += -Werror
diff --git a/include/kvm/uip.h b/include/kvm/uip.h
index a9a8d85..5d33532 100644
--- a/include/kvm/uip.h
+++ b/include/kvm/uip.h
@@ -21,6 +21,10 @@
 #define UIP_IP_P_TCP		0X06
 #define UIP_IP_P_ICMP		0X01
 
+#define UIP_ICMP_ECHO_REPLY	0
+#define UIP_ICMP_UNREACH	5
+#define UIP_ICMP_ECHO		8
+
 #define UIP_TCP_HDR_LEN		0x50
 #define UIP_TCP_WIN_SIZE	14600
 #define UIP_TCP_FLAG_FIN	1
@@ -116,7 +120,6 @@ struct uip_ip {
 } __attribute__((packed));
 
 struct uip_icmp {
-	struct uip_ip ip;
 	u8 type;
 	u8 code;
 	u16 csum;
@@ -125,10 +128,6 @@ struct uip_icmp {
 } __attribute__((packed));
 
 struct uip_udp {
-	/*
-	 * FIXME: IP Options (IP hdr len > 20 bytes) are not supported
-	 */
-	struct uip_ip ip;
 	u16 sport;
 	u16 dport;
 	/*
@@ -140,10 +139,6 @@ struct uip_udp {
 } __attribute__((packed));
 
 struct uip_tcp {
-	/*
-	 * FIXME: IP Options (IP hdr len > 20 bytes) are not supported
-	 */
-	struct uip_ip ip;
 	u16 sport;
 	u16 dport;
 	u32 seq;
@@ -250,6 +245,7 @@ struct uip_tcp_socket {
 	u32 dip, sip;
 	u8 *payload;
 	int fd;
+	int dead;
 };
 
 struct uip_tx_arg {
@@ -265,6 +261,11 @@ static inline u16 uip_ip_hdrlen(struct uip_ip *ip)
 	return (ip->vhl & 0x0f) * 4;
 }
 
+static inline void *uip_ip_proto(struct uip_ip *ip)
+{
+	return ((uint8_t *)&(ip->vhl)) + (ip->vhl & 0x0f) * 4;
+}
+
 static inline u16 uip_ip_len(struct uip_ip *ip)
 {
 	return htons(ip->len);
@@ -285,18 +286,14 @@ static inline u16 uip_tcp_hdrlen(struct uip_tcp *tcp)
 	return (tcp->off >> 4) * 4;
 }
 
-static inline u16 uip_tcp_len(struct uip_tcp *tcp)
+static inline u16 uip_tcp_len(struct uip_ip *ip, struct uip_tcp *tcp)
 {
-	struct uip_ip *ip;
-
-	ip = &tcp->ip;
-
 	return uip_ip_len(ip) - uip_ip_hdrlen(ip);
 }
 
-static inline u16 uip_tcp_payloadlen(struct uip_tcp *tcp)
+static inline u16 uip_tcp_payloadlen(struct uip_ip *ip, struct uip_tcp *tcp)
 {
-	return uip_tcp_len(tcp) - uip_tcp_hdrlen(tcp);
+	return uip_tcp_len(ip, tcp) - uip_tcp_hdrlen(tcp);
 }
 
 static inline u8 *uip_tcp_payload(struct uip_tcp *tcp)
@@ -304,6 +301,11 @@ static inline u8 *uip_tcp_payload(struct uip_tcp *tcp)
 	return (u8 *)&tcp->sport + uip_tcp_hdrlen(tcp);
 }
 
+static inline bool uip_tcp_is_rst(struct uip_tcp *tcp)
+{
+	return (tcp->flg & UIP_TCP_FLAG_RST) != 0;
+}
+
 static inline bool uip_tcp_is_syn(struct uip_tcp *tcp)
 {
 	return (tcp->flg & UIP_TCP_FLAG_SYN) != 0;
@@ -314,6 +316,11 @@ static inline bool uip_tcp_is_fin(struct uip_tcp *tcp)
 	return (tcp->flg & UIP_TCP_FLAG_FIN) != 0;
 }
 
+static inline bool uip_tcp_is_ack(struct uip_tcp *tcp)
+{
+	return (tcp->flg & UIP_TCP_FLAG_ACK) != 0;
+}
+
 static inline u32 uip_tcp_isn(struct uip_tcp *tcp)
 {
 	return ntohl(tcp->seq);
@@ -344,9 +351,9 @@ int uip_tx_do_ipv4_udp(struct uip_tx_arg *arg);
 int uip_tx_do_ipv4(struct uip_tx_arg *arg);
 int uip_tx_do_arp(struct uip_tx_arg *arg);
 
-u16 uip_csum_icmp(struct uip_icmp *icmp);
-u16 uip_csum_udp(struct uip_udp *udp);
-u16 uip_csum_tcp(struct uip_tcp *tcp);
+u16 uip_csum_icmp(struct uip_ip *ip, struct uip_icmp *icmp);
+u16 uip_csum_udp(struct uip_ip *ip, struct uip_udp *udp);
+u16 uip_csum_tcp(struct uip_ip *ip, struct uip_tcp *tcp);
 u16 uip_csum_ip(struct uip_ip *ip);
 
 struct uip_buf *uip_buf_set_used(struct uip_info *info, struct uip_buf *buf);
diff --git a/net/uip/csum.c b/net/uip/csum.c
index 7ca8bad..8f21da5 100644
--- a/net/uip/csum.c
+++ b/net/uip/csum.c
@@ -24,23 +24,17 @@ u16 uip_csum_ip(struct uip_ip *ip)
 	return uip_csum(0, &ip->vhl, uip_ip_hdrlen(ip));
 }
 
-u16 uip_csum_icmp(struct uip_icmp *icmp)
+u16 uip_csum_icmp(struct uip_ip *ip, struct uip_icmp *icmp)
 {
-	struct uip_ip *ip;
-
-	ip = &icmp->ip;
 	return icmp->csum = uip_csum(0, &icmp->type, htons(ip->len) - uip_ip_hdrlen(ip) - 8); /* icmp header len = 8 */
 }
 
-u16 uip_csum_udp(struct uip_udp *udp)
+u16 uip_csum_udp(struct uip_ip *ip, struct uip_udp *udp)
 {
 	struct uip_pseudo_hdr hdr;
-	struct uip_ip *ip;
 	int udp_len;
 	u8 *pad;
 
-	ip	  = &udp->ip;
-
 	hdr.sip   = ip->sip;
 	hdr.dip	  = ip->dip;
 	hdr.zero  = 0;
@@ -61,14 +55,12 @@ u16 uip_csum_udp(struct uip_udp *udp)
 
 }
 
-u16 uip_csum_tcp(struct uip_tcp *tcp)
+u16 uip_csum_tcp(struct uip_ip *ip, struct uip_tcp *tcp)
 {
 	struct uip_pseudo_hdr hdr;
-	struct uip_ip *ip;
 	u16 tcp_len;
 	u8 *pad;
 
-	ip	  = &tcp->ip;
 	tcp_len   = ntohs(ip->len) - uip_ip_hdrlen(ip);
 
 	hdr.sip   = ip->sip;
diff --git a/net/uip/dhcp.c b/net/uip/dhcp.c
index b17d352..f706eba 100644
--- a/net/uip/dhcp.c
+++ b/net/uip/dhcp.c
@@ -144,9 +144,10 @@ static int uip_dhcp_fill_option(struct uip_info *info, struct uip_dhcp *dhcp, in
 static int uip_dhcp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, struct uip_buf *buf, u8 reply_msg_type)
 {
 	struct uip_dhcp *dhcp;
+	struct uip_ip *ip;
 
-	dhcp		= (struct uip_dhcp *)buf->eth;
-
+	ip		= (struct uip_ip *)buf->eth;
+	dhcp		= (struct uip_dhcp *)(ip + 1);
 	dhcp->msg_type	= 2;
 	dhcp->client_ip	= 0;
 	dhcp->your_ip	= htonl(info->guest_ip);
@@ -166,12 +167,14 @@ static int uip_dhcp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, s
 int uip_tx_do_ipv4_udp_dhcp(struct uip_tx_arg *arg)
 {
 	struct uip_udp_socket sk;
+	struct uip_ip *ip;
 	struct uip_dhcp *dhcp;
 	struct uip_info *info;
 	struct uip_buf *buf;
 	u8 reply_msg_type;
 
-	dhcp = (struct uip_dhcp *)arg->eth;
+	ip = (struct uip_ip *)arg->eth;
+	dhcp = (struct uip_dhcp *)(((uint8_t *)ip) + uip_ip_hdrlen(ip));
 
 	if (uip_dhcp_is_discovery(dhcp))
 		reply_msg_type = UIP_DHCP_OFFER;
diff --git a/net/uip/icmp.c b/net/uip/icmp.c
index 233297c..ee98ebc 100644
--- a/net/uip/icmp.c
+++ b/net/uip/icmp.c
@@ -4,26 +4,35 @@ int uip_tx_do_ipv4_icmp(struct uip_tx_arg *arg)
 {
 	struct uip_ip *ip, *ip2;
 	struct uip_icmp *icmp2;
+	struct uip_icmp *icmp;
 	struct uip_buf *buf;
 
-	buf		= uip_buf_clone(arg);
-
-	icmp2		= (struct uip_icmp *)(buf->eth);
-	ip2		= (struct uip_ip *)(buf->eth);
 	ip		= (struct uip_ip *)(arg->eth);
+	icmp		= uip_ip_proto(ip);
 
-	ip2->sip	= ip->dip;
-	ip2->dip	= ip->sip;
-	ip2->csum	= 0;
-	/*
-	 * ICMP reply: 0
-	 */
-	icmp2->type	= 0;
-	icmp2->csum	= 0;
-	ip2->csum	= uip_csum_ip(ip2);
-	icmp2->csum	= uip_csum_icmp(icmp2);
+	/* Check the icmp type first.. */
 
-	uip_buf_set_used(arg->info, buf);
+	switch(icmp->type) {
+	case UIP_ICMP_ECHO:
+		buf		= uip_buf_clone(arg);
+		ip2		= (struct uip_ip *)(buf->eth);
+		icmp2		= uip_ip_proto(ip2);
+		ip2->sip	= ip->dip;
+		ip2->dip	= ip->sip;
+		ip2->csum	= 0;
+		/*
+		 * ICMP reply: 0
+		 */
+		icmp2->type	= UIP_ICMP_ECHO_REPLY;
+		icmp2->csum	= 0;
+		ip2->csum	= uip_csum_ip(ip2);
+		icmp2->csum	= uip_csum_icmp(ip2, icmp2);
 
-	return 0;
+		uip_buf_set_used(arg->info, buf);
+
+		return 0;
+	/* FIXME: need to process unreachable reports */
+	default:
+		return 0;
+	}
 }
diff --git a/net/uip/ipv4.c b/net/uip/ipv4.c
index 58373fd..97812e2 100644
--- a/net/uip/ipv4.c
+++ b/net/uip/ipv4.c
@@ -3,14 +3,18 @@
 int uip_tx_do_ipv4(struct uip_tx_arg *arg)
 {
 	struct uip_ip *ip;
+	int n;
+	uint8_t *p;
 
 	ip = (struct uip_ip *)(arg->eth);
 
-	if (uip_ip_hdrlen(ip) != 20) {
-		pr_warning("IP header length is not 20 bytes");
-		return -1;
-	}
+	p = (uint8_t *)arg->eth;
 
+	for (n = 0; n < 64; n++) {
+		printf("%02X ", *p++);
+		if ((n & 7) == 7)
+			printf("\n");
+	}
 	switch (ip->proto) {
 	case UIP_IP_P_ICMP:
 		uip_tx_do_ipv4_icmp(arg);
diff --git a/net/uip/tcp.c b/net/uip/tcp.c
index 3c30ade..964c929 100644
--- a/net/uip/tcp.c
+++ b/net/uip/tcp.c
@@ -45,54 +45,6 @@ static struct uip_tcp_socket *uip_tcp_socket_find(struct uip_tx_arg *arg, u32 si
 	return NULL;
 }
 
-static struct uip_tcp_socket *uip_tcp_socket_alloc(struct uip_tx_arg *arg, u32 sip, u32 dip, u16 sport, u16 dport)
-{
-	struct list_head *sk_head;
-	struct uip_tcp_socket *sk;
-	struct mutex *sk_lock;
-	struct uip_tcp *tcp;
-	struct uip_ip *ip;
-	int ret;
-
-	tcp = (struct uip_tcp *)arg->eth;
-	ip = (struct uip_ip *)arg->eth;
-
-	sk_head = &arg->info->tcp_socket_head;
-	sk_lock = &arg->info->tcp_socket_lock;
-
-	sk = malloc(sizeof(*sk));
-	memset(sk, 0, sizeof(*sk));
-
-	sk->lock			= sk_lock;
-	sk->info			= arg->info;
-
-	sk->fd				= socket(AF_INET, SOCK_STREAM, 0);
-	sk->addr.sin_family		= AF_INET;
-	sk->addr.sin_port		= dport;
-	sk->addr.sin_addr.s_addr	= dip;
-
-	pthread_cond_init(&sk->cond, NULL);
-
-	if (ntohl(dip) == arg->info->host_ip)
-		sk->addr.sin_addr.s_addr = inet_addr("127.0.0.1");
-
-	ret = connect(sk->fd, (struct sockaddr *)&sk->addr, sizeof(sk->addr));
-	if (ret) {
-		free(sk);
-		return NULL;
-	}
-
-	sk->sip		= ip->sip;
-	sk->dip		= ip->dip;
-	sk->sport	= tcp->sport;
-	sk->dport	= tcp->dport;
-
-	mutex_lock(sk_lock);
-	list_add_tail(&sk->list, sk_head);
-	mutex_unlock(sk_lock);
-
-	return sk;
-}
 
 static int uip_tcp_payload_send(struct uip_tcp_socket *sk, u8 flag, u16 payload_len)
 {
@@ -112,9 +64,9 @@ static int uip_tcp_payload_send(struct uip_tcp_socket *sk, u8 flag, u16 payload_
 	/*
 	 * Cook a ethernet frame
 	 */
-	tcp2		= (struct uip_tcp *)buf->eth;
 	eth2		= (struct uip_eth *)buf->eth;
 	ip2		= (struct uip_ip *)buf->eth;
+	tcp2		= (struct uip_tcp *)(ip2 + 1);
 
 	eth2->src	= info->host_mac;
 	eth2->dst	= info->guest_mac;
@@ -148,7 +100,7 @@ static int uip_tcp_payload_send(struct uip_tcp_socket *sk, u8 flag, u16 payload_
 
 	ip2->len	= htons(uip_tcp_hdrlen(tcp2) + payload_len + uip_ip_hdrlen(ip2));
 	ip2->csum	= uip_csum_ip(ip2);
-	tcp2->csum	= uip_csum_tcp(tcp2);
+	tcp2->csum	= uip_csum_tcp(ip2, tcp2);
 
 	/*
 	 * virtio_net_hdr
@@ -171,6 +123,57 @@ static int uip_tcp_payload_send(struct uip_tcp_socket *sk, u8 flag, u16 payload_
 	return 0;
 }
 
+static struct uip_tcp_socket *uip_tcp_socket_alloc(struct uip_tx_arg *arg, u32 sip, u32 dip, u16 sport, u16 dport)
+{
+	struct list_head *sk_head;
+	struct uip_tcp_socket *sk;
+	struct mutex *sk_lock;
+	struct uip_tcp *tcp;
+	struct uip_ip *ip;
+	int ret;
+
+	ip = (struct uip_ip *)arg->eth;
+	tcp = (struct uip_tcp *)(ip + 1);
+
+	sk_head = &arg->info->tcp_socket_head;
+	sk_lock = &arg->info->tcp_socket_lock;
+
+	sk = malloc(sizeof(*sk));
+	memset(sk, 0, sizeof(*sk));
+
+	sk->lock			= sk_lock;
+	sk->info			= arg->info;
+
+	sk->fd				= socket(AF_INET, SOCK_STREAM, 0);
+	sk->addr.sin_family		= AF_INET;
+	sk->addr.sin_port		= dport;
+	sk->addr.sin_addr.s_addr	= dip;
+
+	pthread_cond_init(&sk->cond, NULL);
+
+	if (ntohl(dip) == arg->info->host_ip)
+		sk->addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+	sk->sip		= ip->sip;
+	sk->dip		= ip->dip;
+	sk->sport	= tcp->sport;
+	sk->dport	= tcp->dport;
+
+	ret = connect(sk->fd, (struct sockaddr *)&sk->addr, sizeof(sk->addr));
+	if (ret) {
+		perror("connect");
+		uip_tcp_payload_send(sk, UIP_TCP_FLAG_RST, 0);
+		free(sk);
+		return NULL;
+	}
+
+	mutex_lock(sk_lock);
+	list_add_tail(&sk->list, sk_head);
+	mutex_unlock(sk_lock);
+
+	return sk;
+}
+
 static void *uip_tcp_socket_thread(void *p)
 {
 	struct uip_tcp_socket *sk;
@@ -190,7 +193,7 @@ static void *uip_tcp_socket_thread(void *p)
 
 		ret = read(sk->fd, payload, UIP_MAX_TCP_PAYLOAD);
 
-		if (ret <= 0 || ret > UIP_MAX_TCP_PAYLOAD)
+		if (ret <= 0 || ret > UIP_MAX_TCP_PAYLOAD || sk->dead)
 			goto out;
 
 		left = ret;
@@ -238,7 +241,8 @@ static int uip_tcp_socket_receive(struct uip_tcp_socket *sk)
 	return 0;
 }
 
-static int uip_tcp_socket_send(struct uip_tcp_socket *sk, struct uip_tcp *tcp)
+static int uip_tcp_socket_send(struct uip_tcp_socket *sk, struct uip_ip *ip,
+				struct uip_tcp *tcp)
 {
 	int len;
 	int ret;
@@ -248,7 +252,7 @@ static int uip_tcp_socket_send(struct uip_tcp_socket *sk, struct uip_tcp *tcp)
 		return 0;
 
 	payload = uip_tcp_payload(tcp);
-	len = uip_tcp_payloadlen(tcp);
+	len = uip_tcp_payloadlen(ip, tcp);
 
 	ret = write(sk->fd, payload, len);
 	if (ret != len)
@@ -264,44 +268,44 @@ int uip_tx_do_ipv4_tcp(struct uip_tx_arg *arg)
 	struct uip_ip *ip;
 	int ret;
 
-	tcp = (struct uip_tcp *)arg->eth;
 	ip = (struct uip_ip *)arg->eth;
-
-	/*
-	 * Guest is trying to start a TCP session, let's fake SYN-ACK to guest
-	 */
-	if (uip_tcp_is_syn(tcp)) {
-		sk = uip_tcp_socket_alloc(arg, ip->sip, ip->dip, tcp->sport, tcp->dport);
-		if (!sk)
-			return -1;
-
-		sk->window_size = ntohs(tcp->win);
-
-		/*
-		 * Setup ISN number
-		 */
-		sk->isn_guest  = uip_tcp_isn(tcp);
-		sk->isn_server = uip_tcp_isn_alloc();
-
-		sk->seq_server = sk->isn_server;
-		sk->ack_server = sk->isn_guest + 1;
-		uip_tcp_payload_send(sk, UIP_TCP_FLAG_SYN | UIP_TCP_FLAG_ACK, 0);
-		sk->seq_server += 1;
-
-		/*
-		 * Start receive thread for data from remote to guest
-		 */
-		uip_tcp_socket_receive(sk);
-
-		goto out;
-	}
+	tcp = uip_ip_proto(ip);
 
 	/*
 	 * Find socket we have allocated
 	 */
 	sk = uip_tcp_socket_find(arg, ip->sip, ip->dip, tcp->sport, tcp->dport);
-	if (!sk)
-		return -1;
+	if (!sk) {
+		/*
+		 * Guest is trying to start a TCP session, let's fake SYN-ACK to guest
+		 */
+		if (uip_tcp_is_syn(tcp) && !uip_tcp_is_rst(tcp)) {
+			sk = uip_tcp_socket_alloc(arg, ip->sip, ip->dip, tcp->sport, tcp->dport);
+			if (!sk)
+				return -1;
+			sk->window_size = ntohs(tcp->win);
+
+			/*
+			 * Setup ISN number
+			 */
+			sk->isn_guest  = uip_tcp_isn(tcp);
+			sk->isn_server = uip_tcp_isn_alloc();
+
+			sk->seq_server = sk->isn_server;
+			sk->ack_server = sk->isn_guest + 1;
+			uip_tcp_payload_send(sk,
+				UIP_TCP_FLAG_SYN | UIP_TCP_FLAG_ACK, 0);
+			sk->seq_server += 1;
+
+			/*
+			 * Start receive thread for data from remote to guest
+			 */
+			uip_tcp_socket_receive(sk);
+
+			goto out;
+		}
+	}
+
 
 	mutex_lock(sk->lock);
 	sk->window_size = ntohs(tcp->win);
@@ -309,6 +313,12 @@ int uip_tx_do_ipv4_tcp(struct uip_tx_arg *arg)
 	pthread_cond_signal(&sk->cond);
 	mutex_unlock(sk->lock);
 
+	if (uip_tcp_is_rst(tcp)) {
+		sk->dead = 1;
+		goto out;
+	}
+
+	/* Really ought to do fin processing post data */
 	if (uip_tcp_is_fin(tcp)) {
 		if (sk->write_done)
 			goto out;
@@ -328,13 +338,13 @@ int uip_tx_do_ipv4_tcp(struct uip_tx_arg *arg)
 	/*
 	 * Ignore guest to server frames with zero tcp payload
 	 */
-	if (uip_tcp_payloadlen(tcp) == 0)
+	if (uip_tcp_payloadlen(ip, tcp) == 0)
 		goto out;
 
 	/*
 	 * Sent out TCP data to remote host
 	 */
-	ret = uip_tcp_socket_send(sk, tcp);
+	ret = uip_tcp_socket_send(sk, ip, tcp);
 	if (ret < 0)
 		return -1;
 	/*
diff --git a/net/uip/udp.c b/net/uip/udp.c
index dd288c5..9dddb4f 100644
--- a/net/uip/udp.c
+++ b/net/uip/udp.c
@@ -108,9 +108,9 @@ int uip_udp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, struct ui
 	/*
 	 * Cook a ethernet frame
 	 */
-	udp2		= (struct uip_udp *)(buf->eth);
 	eth2		= (struct uip_eth *)buf->eth;
 	ip2		= (struct uip_ip *)(buf->eth);
+	udp2		= (struct uip_udp *)(ip2 + 1);
 
 	eth2->src	= info->host_mac;
 	eth2->dst	= info->guest_mac;
@@ -137,7 +137,7 @@ int uip_udp_make_pkg(struct uip_info *info, struct uip_udp_socket *sk, struct ui
 
 	ip2->len	= udp2->len + htons(uip_ip_hdrlen(ip2));
 	ip2->csum	= uip_csum_ip(ip2);
-	udp2->csum	= uip_csum_udp(udp2);
+	udp2->csum	= uip_csum_udp(ip2, udp2);
 
 	/*
 	 * virtio_net_hdr
@@ -209,8 +209,8 @@ int uip_tx_do_ipv4_udp(struct uip_tx_arg *arg)
 	struct uip_ip *ip;
 	int ret;
 
-	udp	= (struct uip_udp *)(arg->eth);
 	ip	= (struct uip_ip *)(arg->eth);
+	udp	= uip_ip_proto(ip);
 	info	= arg->info;
 
 	if (uip_udp_is_dhcp(udp)) {
@@ -230,6 +230,7 @@ int uip_tx_do_ipv4_udp(struct uip_tx_arg *arg)
 	 */
 	ret = uip_udp_socket_send(sk, udp);
 	if (ret)
+		/* FIXME: icmp port unreach */
 		return -1;
 
 	if (!info->udp_thread)