ether: add soft vlan encap/decap

It is helpful to allow device drivers that don't support hardware
VLAN stripping to emulate this in software. This allows application
to be device independent.

Avoid discarding shared mbufs. Make a copy in rte_vlan_insert() of any
packet to be tagged that has a reference count > 1.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>

diff --git a/lib/librte_ether/rte_ether.h b/lib/librte_ether/rte_ether.h
index 7e7d22c..0797908 100644 (file)
--- a/lib/librte_ether/rte_ether.h
+++ b/lib/librte_ether/rte_ether.h
@@ -49,6 +49,8 @@ extern "C" {
 
 #include <rte_memcpy.h>
 #include <rte_random.h>
+#include <rte_mbuf.h>
+#include <rte_byteorder.h>
 
 #define ETHER_ADDR_LEN  6 /**< Length of Ethernet address. */
 #define ETHER_TYPE_LEN  2 /**< Length of Ethernet type field. */
@@ -333,6 +335,80 @@ struct vxlan_hdr {
 #define ETHER_VXLAN_HLEN (sizeof(struct udp_hdr) + sizeof(struct vxlan_hdr))
 /**< VXLAN tunnel header length. */
 
+/**
+ * Extract VLAN tag information into mbuf
+ *
+ * Software version of VLAN stripping
+ *
+ * @param m
+ *   The packet mbuf.
+ * @return
+ *   - 0: Success
+ *   - 1: not a vlan packet
+ */
+static inline int rte_vlan_strip(struct rte_mbuf *m)
+{
+       struct ether_hdr *eh
+                = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+       if (eh->ether_type != rte_cpu_to_be_16(ETHER_TYPE_VLAN))
+               return -1;
+
+       struct vlan_hdr *vh = (struct vlan_hdr *)(eh + 1);
+       m->ol_flags |= PKT_RX_VLAN_PKT;
+       m->vlan_tci = rte_be_to_cpu_16(vh->vlan_tci);
+
+       /* Copy ether header over rather than moving whole packet */
+       memmove(rte_pktmbuf_adj(m, sizeof(struct vlan_hdr)),
+               eh, 2 * ETHER_ADDR_LEN);
+
+       return 0;
+}
+
+/**
+ * Insert VLAN tag into mbuf.
+ *
+ * Software version of VLAN unstripping
+ *
+ * @param m
+ *   The packet mbuf.
+ * @return
+ *   - 0: On success
+ *   -EPERM: mbuf is is shared overwriting would be unsafe
+ *   -ENOSPC: not enough headroom in mbuf
+ */
+static inline int rte_vlan_insert(struct rte_mbuf **m)
+{
+       struct ether_hdr *oh, *nh;
+       struct vlan_hdr *vh;
+
+#ifdef RTE_MBUF_REFCNT
+       /* Can't insert header if mbuf is shared */
+       if (rte_mbuf_refcnt_read(*m) > 1) {
+               struct rte_mbuf *copy;
+
+               copy = rte_pktmbuf_clone(*m, (*m)->pool);
+               if (unlikely(copy == NULL))
+                       return -ENOMEM;
+               rte_pktmbuf_free(*m);
+               *m = copy;
+       }
+#endif
+       oh = rte_pktmbuf_mtod(*m, struct ether_hdr *);
+       nh = (struct ether_hdr *)
+               rte_pktmbuf_prepend(*m, sizeof(struct vlan_hdr));
+       if (nh == NULL)
+               return -ENOSPC;
+
+       memmove(nh, oh, 2 * ETHER_ADDR_LEN);
+       nh->ether_type = rte_cpu_to_be_16(ETHER_TYPE_VLAN);
+
+       vh = (struct vlan_hdr *) (nh + 1);
+       vh->vlan_tci = rte_cpu_to_be_16((*m)->vlan_tci);
+
+       return 0;
+}
+
 #ifdef __cplusplus
 }
 #endif