diff --git a/include/net/net_pkt.h b/include/net/net_pkt.h
index 51d59516020..3d285404609 100644
--- a/include/net/net_pkt.h
+++ b/include/net/net_pkt.h
@@ -82,8 +82,8 @@ struct net_pkt {
 
 #if defined(CONFIG_NET_IPV6)
 	uint8_t ipv6_hop_limit;	/* IPv6 hop limit for this network packet. */
-	uint8_t ext_len;	/* length of extension headers */
-	uint8_t ext_opt_len;	/* IPv6 ND option length */
+	uint8_t ipv6_ext_len;	/* length of extension headers */
+	uint8_t ipv6_ext_opt_len; /* IPv6 ND option length */
 
 	/* Where is the start of the last header before payload data
 	 * in IPv6 packet. This is offset value from start of the IPv6
@@ -215,24 +215,25 @@ static inline bool net_pkt_forwarding(struct net_pkt *pkt)
 #endif
 
 #if defined(CONFIG_NET_IPV6)
-static inline uint8_t net_pkt_ext_opt_len(struct net_pkt *pkt)
+static inline uint8_t net_pkt_ipv6_ext_opt_len(struct net_pkt *pkt)
 {
-	return pkt->ext_opt_len;
+	return pkt->ipv6_ext_opt_len;
 }
 
-static inline void net_pkt_set_ext_opt_len(struct net_pkt *pkt, uint8_t len)
+static inline void net_pkt_set_ipv6_ext_opt_len(struct net_pkt *pkt,
+						uint8_t len)
 {
-	pkt->ext_opt_len = len;
+	pkt->ipv6_ext_opt_len = len;
 }
 
-static inline uint8_t net_pkt_ext_len(struct net_pkt *pkt)
+static inline uint8_t net_pkt_ipv6_ext_len(struct net_pkt *pkt)
 {
-	return pkt->ext_len;
+	return pkt->ipv6_ext_len;
 }
 
-static inline void net_pkt_set_ext_len(struct net_pkt *pkt, uint8_t len)
+static inline void net_pkt_set_ipv6_ext_len(struct net_pkt *pkt, uint8_t len)
 {
-	pkt->ext_len = len;
+	pkt->ipv6_ext_len = len;
 }
 
 static inline uint16_t net_pkt_ipv6_hdr_prev(struct net_pkt *pkt)
@@ -292,8 +293,8 @@ static inline void net_pkt_set_ipv6_fragment_id(struct net_pkt *pkt,
 }
 #endif /* CONFIG_NET_IPV6_FRAGMENT */
 #else /* CONFIG_NET_IPV6 */
-#define net_pkt_ext_len(...) 0
-#define net_pkt_set_ext_len(...)
+#define net_pkt_ipv6_ext_len(...) 0
+#define net_pkt_set_ipv6_ext_len(...)
 #endif /* CONFIG_NET_IPV6 */
 
 static inline size_t net_pkt_get_len(struct net_pkt *pkt)
@@ -309,19 +310,19 @@ static inline uint8_t *net_pkt_ip_data(struct net_pkt *pkt)
 static inline uint8_t *net_pkt_udp_data(struct net_pkt *pkt)
 {
 	return &pkt->frags->data[net_pkt_ip_hdr_len(pkt) +
-				 net_pkt_ext_len(pkt)];
+				 net_pkt_ipv6_ext_len(pkt)];
 }
 
 static inline uint8_t *net_pkt_tcp_data(struct net_pkt *pkt)
 {
 	return &pkt->frags->data[net_pkt_ip_hdr_len(pkt) +
-				 net_pkt_ext_len(pkt)];
+				 net_pkt_ipv6_ext_len(pkt)];
 }
 
 static inline uint8_t *net_pkt_icmp_data(struct net_pkt *pkt)
 {
 	return &pkt->frags->data[net_pkt_ip_hdr_len(pkt) +
-				 net_pkt_ext_len(pkt)];
+				 net_pkt_ipv6_ext_len(pkt)];
 }
 
 static inline uint8_t *net_pkt_appdata(struct net_pkt *pkt)
diff --git a/subsys/net/ip/icmpv6.c b/subsys/net/ip/icmpv6.c
index 899cf40ebd5..ba22e278229 100644
--- a/subsys/net/ip/icmpv6.c
+++ b/subsys/net/ip/icmpv6.c
@@ -154,10 +154,10 @@ static enum net_verdict handle_echo_request(struct net_pkt *orig)
 	net_pkt_set_ll_reserve(pkt, net_buf_headroom(frag));
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 
-	if (net_pkt_ext_len(orig)) {
-		net_pkt_set_ext_len(pkt, net_pkt_ext_len(orig));
+	if (net_pkt_ipv6_ext_len(orig)) {
+		net_pkt_set_ipv6_ext_len(pkt, net_pkt_ipv6_ext_len(orig));
 	} else {
-		net_pkt_set_ext_len(pkt, 0);
+		net_pkt_set_ipv6_ext_len(pkt, 0);
 	}
 
 	/* Set up IPv6 Header fields */
@@ -291,7 +291,7 @@ int net_icmpv6_send_error(struct net_pkt *orig, uint8_t type, uint8_t code,
 	net_pkt_set_family(pkt, AF_INET6);
 	net_pkt_set_iface(pkt, iface);
 	net_pkt_set_ll_reserve(pkt, net_buf_headroom(frag));
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	setup_ipv6_header(pkt, extra_len, net_if_ipv6_get_hop_limit(iface),
 			  type, code);
diff --git a/subsys/net/ip/icmpv6.h b/subsys/net/ip/icmpv6.h
index a846d0132c4..2e6c3049d50 100644
--- a/subsys/net/ip/icmpv6.h
+++ b/subsys/net/ip/icmpv6.h
@@ -82,7 +82,7 @@ struct net_icmpv6_nd_opt_6co {
 #define NET_ICMPV6_ND_OPT_HDR_HDR(pkt)					\
 	((struct net_icmpv6_nd_opt_hdr *)(net_pkt_icmp_data(pkt) +	\
 					  sizeof(struct net_icmp_hdr) +	\
-					  net_pkt_ext_opt_len(pkt)))
+					  net_pkt_ipv6_ext_opt_len(pkt)))
 
 #define NET_ICMPV6_NA_HDR(pkt)						\
 	((struct net_icmpv6_na_hdr *)(net_pkt_icmp_data(pkt) +		\
diff --git a/subsys/net/ip/ipv6.c b/subsys/net/ip/ipv6.c
index 5320e9d6e7d..95001661be2 100644
--- a/subsys/net/ip/ipv6.c
+++ b/subsys/net/ip/ipv6.c
@@ -597,7 +597,7 @@ struct net_pkt *net_ipv6_create_raw(struct net_pkt *pkt,
 	net_ipaddr_copy(&NET_IPV6_HDR(pkt)->dst, dst);
 	net_ipaddr_copy(&NET_IPV6_HDR(pkt)->src, src);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 	NET_IPV6_HDR(pkt)->nexthdr = next_header;
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
@@ -1083,7 +1083,7 @@ int net_ipv6_send_na(struct net_if *iface, struct in6_addr *src,
 
 	llao_len = get_llao_len(iface);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	setup_headers(pkt, sizeof(struct net_icmpv6_na_hdr) + llao_len,
 		      NET_ICMPV6_NA);
@@ -1155,7 +1155,7 @@ static enum net_verdict handle_ns_input(struct net_pkt *pkt)
 		goto drop;
 	}
 
-	net_pkt_set_ext_opt_len(pkt, sizeof(struct net_icmpv6_ns_hdr));
+	net_pkt_set_ipv6_ext_opt_len(pkt, sizeof(struct net_icmpv6_ns_hdr));
 	hdr = NET_ICMPV6_ND_OPT_HDR_HDR(pkt);
 
 	/* The parsing gets tricky if the ND struct is split
@@ -1169,7 +1169,7 @@ static enum net_verdict handle_ns_input(struct net_pkt *pkt)
 	left_len = pkt->frags->len - (sizeof(struct net_ipv6_hdr) +
 				      sizeof(struct net_icmp_hdr));
 
-	while (net_pkt_ext_opt_len(pkt) < left_len &&
+	while (net_pkt_ipv6_ext_opt_len(pkt) < left_len &&
 	       left_len < pkt->frags->len) {
 
 		if (!hdr->len) {
@@ -1191,12 +1191,13 @@ static enum net_verdict handle_ns_input(struct net_pkt *pkt)
 			break;
 		}
 
-		prev_opt_len = net_pkt_ext_opt_len(pkt);
+		prev_opt_len = net_pkt_ipv6_ext_opt_len(pkt);
 
-		net_pkt_set_ext_opt_len(pkt, net_pkt_ext_opt_len(pkt) +
-					 (hdr->len << 3));
+		net_pkt_set_ipv6_ext_opt_len(pkt,
+					     net_pkt_ipv6_ext_opt_len(pkt) +
+					     (hdr->len << 3));
 
-		if (prev_opt_len == net_pkt_ext_opt_len(pkt)) {
+		if (prev_opt_len == net_pkt_ipv6_ext_opt_len(pkt)) {
 			NET_ERR("Corrupted NS message");
 			goto drop;
 		}
@@ -1597,7 +1598,7 @@ static enum net_verdict handle_na_input(struct net_pkt *pkt)
 		goto drop;
 	}
 
-	net_pkt_set_ext_opt_len(pkt, sizeof(struct net_icmpv6_na_hdr));
+	net_pkt_set_ipv6_ext_opt_len(pkt, sizeof(struct net_icmpv6_na_hdr));
 	hdr = NET_ICMPV6_ND_OPT_HDR_HDR(pkt);
 
 	/* The parsing gets tricky if the ND struct is split
@@ -1611,7 +1612,7 @@ static enum net_verdict handle_na_input(struct net_pkt *pkt)
 	left_len = pkt->frags->len - (sizeof(struct net_ipv6_hdr) +
 				      sizeof(struct net_icmp_hdr));
 
-	while (net_pkt_ext_opt_len(pkt) < left_len &&
+	while (net_pkt_ipv6_ext_opt_len(pkt) < left_len &&
 	       left_len < pkt->frags->len) {
 
 		if (!hdr->len) {
@@ -1628,12 +1629,13 @@ static enum net_verdict handle_na_input(struct net_pkt *pkt)
 			break;
 		}
 
-		prev_opt_len = net_pkt_ext_opt_len(pkt);
+		prev_opt_len = net_pkt_ipv6_ext_opt_len(pkt);
 
-		net_pkt_set_ext_opt_len(pkt, net_pkt_ext_opt_len(pkt) +
-					 (hdr->len << 3));
+		net_pkt_set_ipv6_ext_opt_len(pkt,
+					     net_pkt_ipv6_ext_opt_len(pkt) +
+					     (hdr->len << 3));
 
-		if (prev_opt_len == net_pkt_ext_opt_len(pkt)) {
+		if (prev_opt_len == net_pkt_ipv6_ext_opt_len(pkt)) {
 			NET_ERR("Corrupted NA message");
 			goto drop;
 		}
@@ -2207,7 +2209,7 @@ static enum net_verdict handle_ra_input(struct net_pkt *pkt)
 	}
 
 	frag = pkt->frags;
-	offset = sizeof(struct net_ipv6_hdr) + net_pkt_ext_len(pkt) +
+	offset = sizeof(struct net_ipv6_hdr) + net_pkt_ipv6_ext_len(pkt) +
 		sizeof(struct net_icmp_hdr);
 
 	frag = net_frag_read_u8(frag, offset, &offset, &hop_limit);
@@ -2453,7 +2455,7 @@ static int send_mldv2_raw(struct net_if *iface, struct net_buf *frags)
 		goto drop;
 	}
 
-	net_pkt_set_ext_len(pkt, ROUTER_ALERT_LEN);
+	net_pkt_set_ipv6_ext_len(pkt, ROUTER_ALERT_LEN);
 
 	net_pkt_write_be16(pkt, pkt->frags,
 			   NET_IPV6H_LEN + ROUTER_ALERT_LEN + 2,
@@ -2608,7 +2610,7 @@ static enum net_verdict handle_mld_query(struct net_pkt *pkt)
 		goto drop;
 	}
 
-	pkt_len = sizeof(struct net_ipv6_hdr) +	net_pkt_ext_len(pkt) +
+	pkt_len = sizeof(struct net_ipv6_hdr) +	net_pkt_ipv6_ext_len(pkt) +
 		sizeof(struct net_icmp_hdr) + (2 + 2 + 16 + 2 + 2) +
 		sizeof(struct in6_addr) * num_src;
 
@@ -2873,11 +2875,11 @@ static void reassemble_packet(struct net_ipv6_reassembly *reass)
 	}
 
 	/* Fix the total length of the IPv6 packet. */
-	len = net_pkt_ext_len(pkt);
+	len = net_pkt_ipv6_ext_len(pkt);
 	if (len > 0) {
 		NET_DBG("Old pkt %p IPv6 ext len is %d bytes", pkt, len);
-		net_pkt_set_ext_len(pkt,
-				    len - sizeof(struct net_ipv6_frag_hdr));
+		net_pkt_set_ipv6_ext_len(pkt,
+				len - sizeof(struct net_ipv6_frag_hdr));
 	}
 
 	len = net_pkt_get_len(pkt) - sizeof(struct net_ipv6_hdr);
@@ -3157,8 +3159,8 @@ static int send_ipv6_fragment(struct net_if *iface,
 	/* Update the extension length metadata so that upper layer checksum
 	 * will be calculated properly by net_ipv6_finalize_raw().
 	 */
-	ext_len = net_pkt_ext_len(ipv6) + sizeof(struct net_ipv6_frag_hdr);
-	net_pkt_set_ext_len(ipv6, ext_len);
+	ext_len = net_pkt_ipv6_ext_len(ipv6) + sizeof(struct net_ipv6_frag_hdr);
+	net_pkt_set_ipv6_ext_len(ipv6, ext_len);
 
 	orig_copy = net_buf_clone(orig, FRAG_BUF_WAIT);
 	if (!orig_copy) {
@@ -3262,7 +3264,7 @@ int net_ipv6_send_fragmented_pkt(struct net_if *iface, struct net_pkt *pkt,
 	 * fragmentation header.
 	 */
 	ret = net_pkt_split(pkt, frag,
-			    net_pkt_ip_hdr_len(pkt) + net_pkt_ext_len(pkt),
+			    net_pkt_ip_hdr_len(pkt) + net_pkt_ipv6_ext_len(pkt),
 			    &orig_ipv6, &rest, FRAG_BUF_WAIT);
 	if (ret < 0) {
 		return -ENOMEM;
@@ -3556,7 +3558,7 @@ enum net_verdict net_ipv6_process_pkt(struct net_pkt *pkt)
 
 	/* Check extension headers */
 	net_pkt_set_next_hdr(pkt, &hdr->nexthdr);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 
 	/* Fast path for main upper layer protocols. The handling of extension
@@ -3581,8 +3583,8 @@ enum net_verdict net_ipv6_process_pkt(struct net_pkt *pkt)
 
 		if (is_upper_layer_protocol_header(next)) {
 			NET_DBG("IPv6 next header %d", next);
-			net_pkt_set_ext_len(pkt, offset -
-					    sizeof(struct net_ipv6_hdr));
+			net_pkt_set_ipv6_ext_len(pkt, offset -
+						 sizeof(struct net_ipv6_hdr));
 			goto upper_proto;
 		}
 
@@ -3659,7 +3661,7 @@ enum net_verdict net_ipv6_process_pkt(struct net_pkt *pkt)
 upper_proto:
 	if (total_len > 0) {
 		NET_DBG("Extension len %d", total_len);
-		net_pkt_set_ext_len(pkt, total_len);
+		net_pkt_set_ipv6_ext_len(pkt, total_len);
 	}
 
 	switch (next) {
diff --git a/subsys/net/ip/rpl.c b/subsys/net/ip/rpl.c
index 21d262531c0..2500edf56bb 100644
--- a/subsys/net/ip/rpl.c
+++ b/subsys/net/ip/rpl.c
@@ -3783,7 +3783,7 @@ struct net_buf *net_rpl_verify_header(struct net_pkt *pkt, struct net_buf *frag,
 
 static inline int add_rpl_opt(struct net_pkt *pkt, uint16_t offset)
 {
-	int ext_len = net_pkt_ext_len(pkt);
+	int ext_len = net_pkt_ipv6_ext_len(pkt);
 	bool ret;
 
 	/* next header */
@@ -3836,7 +3836,7 @@ static inline int add_rpl_opt(struct net_pkt *pkt, uint16_t offset)
 
 	NET_IPV6_HDR(pkt)->nexthdr = NET_IPV6_NEXTHDR_HBHO;
 
-	net_pkt_set_ext_len(pkt, ext_len + NET_RPL_HOP_BY_HOP_LEN);
+	net_pkt_set_ipv6_ext_len(pkt, ext_len + NET_RPL_HOP_BY_HOP_LEN);
 
 	return 0;
 }
diff --git a/subsys/net/ip/utils.c b/subsys/net/ip/utils.c
index a1d9ee4cf5f..a3b1fa23fe0 100644
--- a/subsys/net/ip/utils.c
+++ b/subsys/net/ip/utils.c
@@ -405,7 +405,7 @@ static inline uint16_t calc_chksum_pkt(uint16_t sum, struct net_pkt *pkt,
 {
 	struct net_buf *frag = pkt->frags;
 	uint16_t proto_len = net_pkt_ip_hdr_len(pkt) +
-		net_pkt_ext_len(pkt);
+		net_pkt_ipv6_ext_len(pkt);
 	int16_t len = frag->len - proto_len;
 	uint8_t *ptr = frag->data + proto_len;
 
@@ -453,7 +453,7 @@ uint16_t net_calc_chksum(struct net_pkt *pkt, uint8_t proto)
 	case AF_INET:
 		upper_layer_len = (NET_IPV4_HDR(pkt)->len[0] << 8) +
 			NET_IPV4_HDR(pkt)->len[1] -
-			net_pkt_ext_len(pkt) -
+			net_pkt_ipv6_ext_len(pkt) -
 			net_pkt_ip_hdr_len(pkt);
 
 		if (proto == IPPROTO_ICMP) {
@@ -470,7 +470,7 @@ uint16_t net_calc_chksum(struct net_pkt *pkt, uint8_t proto)
 #if defined(CONFIG_NET_IPV6)
 	case AF_INET6:
 		upper_layer_len = (NET_IPV6_HDR(pkt)->len[0] << 8) +
-			NET_IPV6_HDR(pkt)->len[1] - net_pkt_ext_len(pkt);
+			NET_IPV6_HDR(pkt)->len[1] - net_pkt_ipv6_ext_len(pkt);
 		sum = calc_chksum(upper_layer_len + proto,
 				  (uint8_t *)&NET_IPV6_HDR(pkt)->src,
 				  2 * sizeof(struct in6_addr));
diff --git a/tests/net/tcp/src/main.c b/tests/net/tcp/src/main.c
index 86bf1e750c9..a7a9294db31 100644
--- a/tests/net/tcp/src/main.c
+++ b/tests/net/tcp/src/main.c
@@ -277,7 +277,7 @@ static void setup_ipv6_tcp(struct net_pkt *pkt,
 	NET_TCP_HDR(pkt)->src_port = htons(remote_port);
 	NET_TCP_HDR(pkt)->dst_port = htons(local_port);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	net_buf_add(pkt->frags, net_pkt_ip_hdr_len(pkt) +
 				sizeof(struct net_tcp_hdr));
@@ -305,7 +305,7 @@ static void setup_ipv4_tcp(struct net_pkt *pkt,
 	NET_TCP_HDR(pkt)->src_port = htons(remote_port);
 	NET_TCP_HDR(pkt)->dst_port = htons(local_port);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	net_buf_add(pkt->frags, net_pkt_ip_hdr_len(pkt) +
 				sizeof(struct net_tcp_hdr));
diff --git a/tests/net/udp/src/main.c b/tests/net/udp/src/main.c
index 078c05cb015..1e96b563114 100644
--- a/tests/net/udp/src/main.c
+++ b/tests/net/udp/src/main.c
@@ -194,7 +194,7 @@ static void setup_ipv6_udp(struct net_pkt *pkt,
 	NET_UDP_HDR(pkt)->src_port = htons(remote_port);
 	NET_UDP_HDR(pkt)->dst_port = htons(local_port);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	net_buf_add(pkt->frags, net_pkt_ip_hdr_len(pkt) +
 				sizeof(struct net_udp_hdr));
@@ -222,7 +222,7 @@ static void setup_ipv4_udp(struct net_pkt *pkt,
 	NET_UDP_HDR(pkt)->src_port = htons(remote_port);
 	NET_UDP_HDR(pkt)->dst_port = htons(local_port);
 
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	net_buf_add(pkt->frags, net_pkt_ip_hdr_len(pkt) +
 				sizeof(struct net_udp_hdr));
diff --git a/tests/net/utils/src/main.c b/tests/net/utils/src/main.c
index 359bd5aaa7f..e00c6768df3 100644
--- a/tests/net/utils/src/main.c
+++ b/tests/net/utils/src/main.c
@@ -168,7 +168,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 	net_pkt_set_family(pkt, AF_INET6);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	/* We need to zero the ICMP checksum */
 	hdr_len = net_pkt_ip_hdr_len(pkt);
@@ -192,7 +192,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 	net_pkt_set_family(pkt, AF_INET6);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	hdr_len = net_pkt_ip_hdr_len(pkt);
 	orig_chksum = (frag->data[hdr_len + 2] << 8) + frag->data[hdr_len + 3];
@@ -221,7 +221,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 	net_pkt_set_family(pkt, AF_INET6);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	hdr_len = net_pkt_ip_hdr_len(pkt);
 	orig_chksum = (frag->data[hdr_len + 2] << 8) + frag->data[hdr_len + 3];
@@ -253,7 +253,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv6_hdr));
 	net_pkt_set_family(pkt, AF_INET6);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	chunk = 29;
 	datalen = sizeof(pkt3) - sizeof(struct net_ipv6_hdr);
@@ -321,7 +321,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv4_hdr));
 	net_pkt_set_family(pkt, AF_INET);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	hdr_len = net_pkt_ip_hdr_len(pkt);
 	orig_chksum = (frag->data[hdr_len + 2] << 8) + frag->data[hdr_len + 3];
@@ -350,7 +350,7 @@ static bool run_tests(void)
 
 	net_pkt_set_ip_hdr_len(pkt, sizeof(struct net_ipv4_hdr));
 	net_pkt_set_family(pkt, AF_INET);
-	net_pkt_set_ext_len(pkt, 0);
+	net_pkt_set_ipv6_ext_len(pkt, 0);
 
 	hdr_len = net_pkt_ip_hdr_len(pkt);
 	orig_chksum = (frag->data[hdr_len + 2] << 8) + frag->data[hdr_len + 3];