struct arp_eth_header *arp;
ofpbuf_clear(b);
- ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN
+ ofpbuf_prealloc_tailroom(b, 2 + ETH_HEADER_LEN + VLAN_HEADER_LEN
+ ARP_ETH_HEADER_LEN);
- ofpbuf_reserve(b, VLAN_HEADER_LEN);
+ ofpbuf_reserve(b, 2 + VLAN_HEADER_LEN);
eth = ofpbuf_put_uninit(b, sizeof *eth);
memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
/* Converts hex digits in 'hex' to an Ethernet packet in '*packetp'. The
* caller must free '*packetp'. On success, returns NULL. On failure, returns
- * an error message and stores NULL in '*packetp'. */
+ * an error message and stores NULL in '*packetp'.
+ *
+ * Aligns the L3 header of '*packetp' on a 32-bit boundary. */
const char *
eth_from_hex(const char *hex, struct ofpbuf **packetp)
{
struct ofpbuf *packet;
- packet = *packetp = ofpbuf_new(strlen(hex) / 2);
+ /* Use 2 bytes of headroom to 32-bit align the L3 header. */
+ packet = *packetp = ofpbuf_new_with_headroom(strlen(hex) / 2, 2);
if (ofpbuf_put_hex(packet, hex, NULL)[0] != '\0') {
ofpbuf_delete(packet);
* 'eth_src' and 'eth_type' parameters. A payload of 'size' bytes is allocated
* in 'b' and returned. This payload may be populated with appropriate
* information by the caller. Sets 'b''s 'l2' and 'l3' pointers to the
- * Ethernet header and payload respectively.
+ * Ethernet header and payload respectively. Aligns b->l3 on a 32-bit
+ * boundary.
*
* The returned packet has enough headroom to insert an 802.1Q VLAN header if
* desired. */
ofpbuf_clear(b);
- ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN + size);
- ofpbuf_reserve(b, VLAN_HEADER_LEN);
+ /* The magic 2 here ensures that the L3 header (when it is added later)
+ * will be 32-bit aligned. */
+ ofpbuf_prealloc_tailroom(b, 2 + ETH_HEADER_LEN + VLAN_HEADER_LEN + size);
+ ofpbuf_reserve(b, 2 + VLAN_HEADER_LEN);
eth = ofpbuf_put_uninit(b, ETH_HEADER_LEN);
data = ofpbuf_put_uninit(b, size);