diff --git a/encap.c b/encap.c
index ca90aa2..1af7376 100644
--- a/encap.c
+++ b/encap.c
@@ -268,7 +268,7 @@ static int gtp1u_udp_encap_recv(struct gtp5g_dev *gtp, struct sk_buff *skb)
 
     // recalculation gtpv1
     gtpv1 = (struct gtpv1_hdr *)(skb->data + sizeof(struct udphdr));
-    pdr = pdr_find_by_gtp1u(gtp, skb, hdrlen, gtpv1->tid);
+    pdr = pdr_find_by_gtp1u(gtp, skb, hdrlen, gtpv1->tid, gtpv1->type);
     // pskb_may_pull() is called in pdr_find_by_gtp1u(), so gtpv1 may be invalidated here.
     // recalculation gtpv1
     gtpv1 = (struct gtpv1_hdr *)(skb->data + sizeof(struct udphdr));
diff --git a/pdr.c b/pdr.c
index 60fe786..9118624 100644
--- a/pdr.c
+++ b/pdr.c
@@ -3,6 +3,7 @@
 #include "dev.h"
 #include "link.h"
 #include "pdr.h"
+#include "gtp.h"
 #include "genl_pdr.h"
 #include "genl_far.h"
 #include "seid.h"
@@ -238,7 +239,7 @@ static int sdf_filter_match(struct sdf_filter *sdf, struct sk_buff *skb,
 }
 
 struct pdr *pdr_find_by_gtp1u(struct gtp5g_dev *gtp, struct sk_buff *skb,
-        unsigned int hdrlen, u32 teid)
+        unsigned int hdrlen, u32 teid, u8 type)
 {
 #ifdef MATCH_IP
     struct iphdr *outer_iph;
@@ -248,6 +249,7 @@ struct pdr *pdr_find_by_gtp1u(struct gtp5g_dev *gtp, struct sk_buff *skb,
     struct hlist_head *head;
     struct pdr *pdr;
     struct pdi *pdi;
+    int may_pull_len;
 
     if (!gtp)
         return NULL;
@@ -255,7 +257,12 @@ struct pdr *pdr_find_by_gtp1u(struct gtp5g_dev *gtp, struct sk_buff *skb,
     if (ntohs(skb->protocol) != ETH_P_IP)
         return NULL;
 
-    if (!pskb_may_pull(skb, hdrlen))
+    if (type == GTPV1_MSG_TYPE_TPDU)
+        may_pull_len = hdrlen + sizeof(struct iphdr);
+    else
+        may_pull_len = hdrlen;
+
+    if (!pskb_may_pull(skb, may_pull_len))
         return NULL;
 
     iph = (struct iphdr *)(skb->data + hdrlen);
diff --git a/pdr.h b/pdr.h
index 3725c85..33b8475 100644
--- a/pdr.h
+++ b/pdr.h
@@ -96,7 +96,7 @@ struct pdr {
 extern void pdr_context_delete(struct pdr *);
 extern struct pdr *find_pdr_by_id(struct gtp5g_dev *, u64, u16);
 extern struct pdr *pdr_find_by_gtp1u(struct gtp5g_dev *, struct sk_buff *,
-        unsigned int, u32);
+        unsigned int, u32, u8);
 extern struct pdr *pdr_find_by_ipv4(struct gtp5g_dev *, struct sk_buff *,
         unsigned int, __be32);
 extern int find_qer_id_in_pdr(struct pdr *, u32);