hw/net/net_rx_pkt: Enforce alignment for eth_header

eth_strip_vlan and eth_strip_vlan_ex refers to ehdr_buf as struct
eth_header. Enforce alignment for the structure.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/net_rx_pkt.c

@@ -23,7 +23,10 @@
 
 struct NetRxPkt {
     struct virtio_net_hdr virt_hdr;
-    uint8_t ehdr_buf[sizeof(struct eth_header) + sizeof(struct vlan_header)];
+    struct {
+        struct eth_header eth;
+        struct vlan_header vlan;
+    } ehdr_buf;
     struct iovec *vec;
     uint16_t vec_len_total;
     uint16_t vec_len;
@@ -89,7 +92,7 @@ net_rx_pkt_pull_data(struct NetRxPkt *pkt,
     if (pkt->ehdr_buf_len) {
         net_rx_pkt_iovec_realloc(pkt, iovcnt + 1);
 
-        pkt->vec[0].iov_base = pkt->ehdr_buf;
+        pkt->vec[0].iov_base = &pkt->ehdr_buf;
         pkt->vec[0].iov_len = pkt->ehdr_buf_len;
 
         pkt->tot_len = pllen + pkt->ehdr_buf_len;
@@ -120,7 +123,7 @@ void net_rx_pkt_attach_iovec(struct NetRxPkt *pkt,
     assert(pkt);
 
     if (strip_vlan) {
-        pkt->ehdr_buf_len = eth_strip_vlan(iov, iovcnt, iovoff, pkt->ehdr_buf,
+        pkt->ehdr_buf_len = eth_strip_vlan(iov, iovcnt, iovoff, &pkt->ehdr_buf,
                                            &ploff, &tci);
     } else {
         pkt->ehdr_buf_len = 0;
@@ -142,7 +145,7 @@ void net_rx_pkt_attach_iovec_ex(struct NetRxPkt *pkt,
 
     if (strip_vlan) {
         pkt->ehdr_buf_len = eth_strip_vlan_ex(iov, iovcnt, iovoff, vet,
-                                              pkt->ehdr_buf,
+                                              &pkt->ehdr_buf,
                                               &ploff, &tci);
     } else {
         pkt->ehdr_buf_len = 0;