diff --git a/hw/net/allwinner-sun8i-emac.c b/hw/net/allwinner-sun8i-emac.c
index 38d3285..0427689 100644
--- a/hw/net/allwinner-sun8i-emac.c
+++ b/hw/net/allwinner-sun8i-emac.c
@@ -514,7 +514,7 @@ static void allwinner_sun8i_emac_transmit(AwSun8iEmacState *s)
         /* After the last descriptor, send the packet */
         if (desc.status2 & TX_DESC_STATUS2_LAST_DESC) {
             if (desc.status2 & TX_DESC_STATUS2_CHECKSUM_MASK) {
-                net_checksum_calculate(packet_buf, packet_bytes);
+                net_checksum_calculate(packet_buf, packet_bytes, CSUM_ALL);
             }
 
             qemu_send_packet(nc, packet_buf, packet_bytes);
diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index 7a53469..9a4474a 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -1266,7 +1266,7 @@ static void gem_transmit(CadenceGEMState *s)
 
                 /* Is checksum offload enabled? */
                 if (s->regs[GEM_DMACFG] & GEM_DMACFG_TXCSUM_OFFL) {
-                    net_checksum_calculate(s->tx_packet, total_bytes);
+                    net_checksum_calculate(s->tx_packet, total_bytes, CSUM_ALL);
                 }
 
                 /* Update MAC statistics */
diff --git a/hw/net/fsl_etsec/rings.c b/hw/net/fsl_etsec/rings.c
index 628648a..121415a 100644
--- a/hw/net/fsl_etsec/rings.c
+++ b/hw/net/fsl_etsec/rings.c
@@ -183,13 +183,11 @@ static void process_tx_fcb(eTSEC *etsec)
     uint8_t *l3_header = etsec->tx_buffer + 8 + l3_header_offset;
     /* L4 header */
     uint8_t *l4_header = l3_header + l4_header_offset;
+    int csum = 0;
 
     /* if packet is IP4 and IP checksum is requested */
     if (flags & FCB_TX_IP && flags & FCB_TX_CIP) {
-        /* do IP4 checksum (TODO This function does TCP/UDP checksum
-         * but not sure if it also does IP4 checksum.) */
-        net_checksum_calculate(etsec->tx_buffer + 8,
-                etsec->tx_buffer_len - 8);
+        csum |= CSUM_IP;
     }
     /* TODO Check the correct usage of the PHCS field of the FCB in case the NPH
      * flag is on */
@@ -201,9 +199,7 @@ static void process_tx_fcb(eTSEC *etsec)
             /* if checksum is requested */
             if (flags & FCB_TX_CTU) {
                 /* do UDP checksum */
-
-                net_checksum_calculate(etsec->tx_buffer + 8,
-                        etsec->tx_buffer_len - 8);
+                csum |= CSUM_UDP;
             } else {
                 /* set checksum field to 0 */
                 l4_header[6] = 0;
@@ -211,10 +207,14 @@ static void process_tx_fcb(eTSEC *etsec)
             }
         } else if (flags & FCB_TX_CTU) { /* if TCP and checksum is requested */
             /* do TCP checksum */
-            net_checksum_calculate(etsec->tx_buffer + 8,
-                                   etsec->tx_buffer_len - 8);
+            csum |= CSUM_TCP;
         }
     }
+
+    if (csum) {
+        net_checksum_calculate(etsec->tx_buffer + 8,
+                               etsec->tx_buffer_len - 8, csum);
+    }
 }
 
 static void process_tx_bd(eTSEC         *etsec,
diff --git a/hw/net/ftgmac100.c b/hw/net/ftgmac100.c
index 782ff19..25685ba 100644
--- a/hw/net/ftgmac100.c
+++ b/hw/net/ftgmac100.c
@@ -564,6 +564,7 @@ static void ftgmac100_do_tx(FTGMAC100State *s, uint32_t tx_ring,
         ptr += len;
         frame_size += len;
         if (bd.des0 & FTGMAC100_TXDES0_LTS) {
+            int csum = 0;
 
             /* Check for VLAN */
             if (flags & FTGMAC100_TXDES1_INS_VLANTAG &&
@@ -573,8 +574,18 @@ static void ftgmac100_do_tx(FTGMAC100State *s, uint32_t tx_ring,
             }
 
             if (flags & FTGMAC100_TXDES1_IP_CHKSUM) {
-                net_checksum_calculate(s->frame, frame_size);
+                csum |= CSUM_IP;
             }
+            if (flags & FTGMAC100_TXDES1_TCP_CHKSUM) {
+                csum |= CSUM_TCP;
+            }
+            if (flags & FTGMAC100_TXDES1_UDP_CHKSUM) {
+                csum |= CSUM_UDP;
+            }
+            if (csum) {
+                net_checksum_calculate(s->frame, frame_size, csum);
+            }
+
             /* Last buffer in frame.  */
             qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
             ptr = s->frame;
diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
index 2c14804..f03450c 100644
--- a/hw/net/imx_fec.c
+++ b/hw/net/imx_fec.c
@@ -561,22 +561,18 @@ static void imx_enet_do_tx(IMXFECState *s, uint32_t index)
         ptr += len;
         frame_size += len;
         if (bd.flags & ENET_BD_L) {
+            int csum = 0;
+
             if (bd.option & ENET_BD_PINS) {
-                struct ip_header *ip_hd = PKT_GET_IP_HDR(s->frame);
-                if (IP_HEADER_VERSION(ip_hd) == 4) {
-                    net_checksum_calculate(s->frame, frame_size);
-                }
+                csum |= (CSUM_TCP | CSUM_UDP);
             }
             if (bd.option & ENET_BD_IINS) {
-                struct ip_header *ip_hd = PKT_GET_IP_HDR(s->frame);
-                /* We compute checksum only for IPv4 frames */
-                if (IP_HEADER_VERSION(ip_hd) == 4) {
-                    uint16_t csum;
-                    ip_hd->ip_sum = 0;
-                    csum = net_raw_checksum((uint8_t *)ip_hd, sizeof(*ip_hd));
-                    ip_hd->ip_sum = cpu_to_be16(csum);
-                }
+                csum |= CSUM_IP;
+            }
+            if (csum) {
+                net_checksum_calculate(s->frame, frame_size, csum);
             }
+
             /* Last buffer in frame.  */
 
             qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 09ceb02..5150f29 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1464,7 +1464,7 @@ static void work_around_broken_dhclient(struct virtio_net_hdr *hdr,
         (buf[12] == 0x08 && buf[13] == 0x00) && /* ethertype == IPv4 */
         (buf[23] == 17) && /* ip.protocol == UDP */
         (buf[34] == 0 && buf[35] == 67)) { /* udp.srcport == bootps */
-        net_checksum_calculate(buf, size);
+        net_checksum_calculate(buf, size, CSUM_UDP);
         hdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM;
     }
 }
diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c
index 00a7fdf..5c815b4 100644
--- a/hw/net/xen_nic.c
+++ b/hw/net/xen_nic.c
@@ -174,7 +174,7 @@ static void net_tx_packets(struct XenNetDev *netdev)
                     tmpbuf = g_malloc(XC_PAGE_SIZE);
                 }
                 memcpy(tmpbuf, page + txreq.offset, txreq.size);
-                net_checksum_calculate(tmpbuf, txreq.size);
+                net_checksum_calculate(tmpbuf, txreq.size, CSUM_ALL);
                 qemu_send_packet(qemu_get_queue(netdev->nic), tmpbuf,
                                  txreq.size);
             } else {
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 05a0d27..7dec37e 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -21,11 +21,16 @@
 #include "qemu/bswap.h"
 struct iovec;
 
+#define CSUM_IP     0x01
+#define CSUM_TCP    0x02
+#define CSUM_UDP    0x04
+#define CSUM_ALL    (CSUM_IP | CSUM_TCP | CSUM_UDP)
+
 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq);
 uint16_t net_checksum_finish(uint32_t sum);
 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
                              uint8_t *addrs, uint8_t *buf);
-void net_checksum_calculate(uint8_t *data, int length);
+void net_checksum_calculate(uint8_t *data, int length, int csum_flag);
 
 static inline uint32_t
 net_checksum_add(int len, uint8_t *buf)
diff --git a/net/checksum.c b/net/checksum.c
index dabd290..70f4eae 100644
--- a/net/checksum.c
+++ b/net/checksum.c
@@ -57,7 +57,7 @@ uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
     return net_checksum_finish(sum);
 }
 
-void net_checksum_calculate(uint8_t *data, int length)
+void net_checksum_calculate(uint8_t *data, int length, int csum_flag)
 {
     int mac_hdr_len, ip_len;
     struct ip_header *ip;
@@ -108,9 +108,11 @@ void net_checksum_calculate(uint8_t *data, int length)
     }
 
     /* Calculate IP checksum */
-    stw_he_p(&ip->ip_sum, 0);
-    csum = net_raw_checksum((uint8_t *)ip, IP_HDR_GET_LEN(ip));
-    stw_be_p(&ip->ip_sum, csum);
+    if (csum_flag & CSUM_IP) {
+        stw_he_p(&ip->ip_sum, 0);
+        csum = net_raw_checksum((uint8_t *)ip, IP_HDR_GET_LEN(ip));
+        stw_be_p(&ip->ip_sum, csum);
+    }
 
     if (IP4_IS_FRAGMENT(ip)) {
         return; /* a fragmented IP packet */
@@ -128,6 +130,10 @@ void net_checksum_calculate(uint8_t *data, int length)
     switch (ip->ip_p) {
     case IP_PROTO_TCP:
     {
+        if (!(csum_flag & CSUM_TCP)) {
+            return;
+        }
+
         tcp_header *tcp = (tcp_header *)(ip + 1);
 
         if (ip_len < sizeof(tcp_header)) {
@@ -148,6 +154,10 @@ void net_checksum_calculate(uint8_t *data, int length)
     }
     case IP_PROTO_UDP:
     {
+        if (!(csum_flag & CSUM_UDP)) {
+            return;
+        }
+
         udp_header *udp = (udp_header *)(ip + 1);
 
         if (ip_len < sizeof(udp_header)) {
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index fc0e64c..10fe393 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -114,7 +114,7 @@ static int handle_primary_tcp_pkt(RewriterState *rf,
             tcp_pkt->th_ack = htonl(ntohl(tcp_pkt->th_ack) + conn->offset);
 
             net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
-                                   pkt->size - pkt->vnet_hdr_len);
+                                   pkt->size - pkt->vnet_hdr_len, CSUM_TCP);
         }
 
         /*
@@ -216,7 +216,7 @@ static int handle_secondary_tcp_pkt(RewriterState *rf,
             tcp_pkt->th_seq = htonl(ntohl(tcp_pkt->th_seq) - conn->offset);
 
             net_checksum_calculate((uint8_t *)pkt->data + pkt->vnet_hdr_len,
-                                   pkt->size - pkt->vnet_hdr_len);
+                                   pkt->size - pkt->vnet_hdr_len, CSUM_TCP);
         }
     }
 
