diff --git a/iov.h b/iov.h
index 6058af7..5668ca5 100644
--- a/iov.h
+++ b/iov.h
@@ -18,6 +18,9 @@
 #include <unistd.h>
 #include <string.h>
 
+#define IOV_OF_LVALUE(lval) \
+	(struct iovec){ .iov_base = &(lval), .iov_len = sizeof(lval) }
+
 size_t iov_skip_bytes(const struct iovec *iov, size_t n,
 		      size_t skip, size_t *offset);
 size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
diff --git a/tap.c b/tap.c
index c6864ac..91fd2e2 100644
--- a/tap.c
+++ b/tap.c
@@ -79,8 +79,7 @@ void tap_send_single(const struct ctx *c, const void *data, size_t l2len)
 	size_t iovcnt = 0;
 
 	if (c->mode == MODE_PASST) {
-		iov[iovcnt].iov_base = &vnet_len;
-		iov[iovcnt].iov_len = sizeof(vnet_len);
+		iov[iovcnt] = IOV_OF_LVALUE(vnet_len);
 		iovcnt++;
 	}
 
diff --git a/tcp.c b/tcp.c
index d42c01d..845afce 100644
--- a/tcp.c
+++ b/tcp.c
@@ -290,6 +290,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "iov.h"
 #include "ip.h"
 #include "passt.h"
 #include "tap.h"
@@ -954,10 +955,8 @@ static void tcp_sock4_iov_init(const struct ctx *c)
 		iov = tcp4_l2_iov[i];
 
 		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp4_payload_tap_hdr[i]);
-		iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
-		iov[TCP_IOV_ETH].iov_len = sizeof(tcp4_eth_src);
-		iov[TCP_IOV_IP].iov_base = &tcp4_payload_ip[i];
-		iov[TCP_IOV_IP].iov_len = sizeof(tcp4_payload_ip[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp4_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_payload_ip[i]);
 		iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_payload[i];
 	}
 
@@ -966,9 +965,8 @@ static void tcp_sock4_iov_init(const struct ctx *c)
 
 		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp4_flags_tap_hdr[i]);
 		iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
-		iov[TCP_IOV_ETH].iov_len = sizeof(tcp4_eth_src);
-		iov[TCP_IOV_IP].iov_base = &tcp4_flags_ip[i];
-		iov[TCP_IOV_IP].iov_len = sizeof(tcp4_flags_ip[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp4_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp4_flags_ip[i]);
 		iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_flags[i];
 	}
 }
@@ -1001,10 +999,8 @@ static void tcp_sock6_iov_init(const struct ctx *c)
 		iov = tcp6_l2_iov[i];
 
 		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp6_payload_tap_hdr[i]);
-		iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
-		iov[TCP_IOV_ETH].iov_len = sizeof(tcp6_eth_src);
-		iov[TCP_IOV_IP].iov_base = &tcp6_payload_ip[i];
-		iov[TCP_IOV_IP].iov_len = sizeof(tcp6_payload_ip[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp6_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_payload_ip[i]);
 		iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_payload[i];
 	}
 
@@ -1012,10 +1008,8 @@ static void tcp_sock6_iov_init(const struct ctx *c)
 		iov = tcp6_l2_flags_iov[i];
 
 		iov[TCP_IOV_TAP] = tap_hdr_iov(c, &tcp6_flags_tap_hdr[i]);
-		iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
-		iov[TCP_IOV_ETH].iov_len = sizeof(tcp6_eth_src);
-		iov[TCP_IOV_IP].iov_base = &tcp6_flags_ip[i];
-		iov[TCP_IOV_IP].iov_len = sizeof(tcp6_flags_ip[i]);
+		iov[TCP_IOV_ETH] = IOV_OF_LVALUE(tcp6_eth_src);
+		iov[TCP_IOV_IP] = IOV_OF_LVALUE(tcp6_flags_ip[i]);
 		iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_flags[i];
 	}
 }
diff --git a/udp.c b/udp.c
index 2d27eae..7186fae 100644
--- a/udp.c
+++ b/udp.c
@@ -113,6 +113,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "iov.h"
 #include "ip.h"
 #include "siphash.h"
 #include "inany.h"
@@ -315,8 +316,7 @@ static void udp_sock4_iov_init_one(const struct ctx *c, size_t i)
 		.iph = L2_BUF_IP4_INIT(IPPROTO_UDP)
 	};
 
-	siov->iov_base	= buf->data;
-	siov->iov_len	= sizeof(buf->data);
+	*siov		= IOV_OF_LVALUE(buf->data);
 
 	mh->msg_name	= &buf->s_in;
 	mh->msg_namelen	= sizeof(buf->s_in);
@@ -343,8 +343,7 @@ static void udp_sock6_iov_init_one(const struct ctx *c, size_t i)
 		.ip6h = L2_BUF_IP6_INIT(IPPROTO_UDP)
 	};
 
-	siov->iov_base	= buf->data;
-	siov->iov_len	= sizeof(buf->data);
+	*siov		= IOV_OF_LVALUE(buf->data);
 
 	mh->msg_name	= &buf->s_in6;
 	mh->msg_namelen	= sizeof(buf->s_in6);