flow: Split flow_extract

Split the L3 and above portion of flow_extract() out into flow_extract_l3_onwards() and call flow_extract_l3_onwards() from flow_extract(). This is to allow re-extraction of l3 and higher information using flow->encap_dl_type which may be set using information contained in actions. Signed-off-by: Simon Horman <[email protected]> Signed-off-by: Ben Pfaff <[email protected]>
wxgospel · Dec 27, 2012 · ad128cc · ad128cc
1 parent e0c91c0
commit ad128cc
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Showing 2 changed files with 31 additions and 5 deletions.
diff --git a/lib/flow.c b/lib/flow.c
@@ -375,9 +375,33 @@ flow_extract(struct ofpbuf *packet, uint32_t skb_priority, uint32_t skb_mark,
     }
     flow->dl_type = parse_ethertype(&b);
 
-    /* Network layer. */
     packet->l3 = b.data;
-    if (flow->dl_type == htons(ETH_TYPE_IP)) {
+    flow_extract_l3_onwards(packet, flow, flow->dl_type);
+}
+
+/* Initializes l3 and higher 'flow' members from 'packet'
+ *
+ * This should be called by or after flow_extract()
+ *
+ * Initializes 'packet' header pointers as follows:
+ *
+ *    - packet->l4 to just past the IPv4 header, if one is present and has a
+ *      correct length, and otherwise NULL.
+ *
+ *    - packet->l7 to just past the TCP or UDP or ICMP header, if one is
+ *      present and has a correct length, and otherwise NULL.
+ */
+void
+flow_extract_l3_onwards(struct ofpbuf *packet, struct flow *flow,
+                        ovs_be16 dl_type)
+{
+    struct ofpbuf b;
+
+    ofpbuf_use_const(&b, packet->l3, packet->size -
+                     (size_t)((char *)packet->l3 - (char *)packet->l2));
+
+    /* Network layer. */
+    if (dl_type == htons(ETH_TYPE_IP)) {
         const struct ip_header *nh = pull_ip(&b);
         if (nh) {
             packet->l4 = b.data;
@@ -410,7 +434,7 @@ flow_extract(struct ofpbuf *packet, uint32_t skb_priority, uint32_t skb_mark,
                 }
             }
         }
-    } else if (flow->dl_type == htons(ETH_TYPE_IPV6)) {
+    } else if (dl_type == htons(ETH_TYPE_IPV6)) {
         if (parse_ipv6(&b, flow)) {
             return;
         }
@@ -425,8 +449,8 @@ flow_extract(struct ofpbuf *packet, uint32_t skb_priority, uint32_t skb_mark,
                 packet->l7 = b.data;
             }
         }
-    } else if (flow->dl_type == htons(ETH_TYPE_ARP) ||
-               flow->dl_type == htons(ETH_TYPE_RARP)) {
+    } else if (dl_type == htons(ETH_TYPE_ARP) ||
+               dl_type == htons(ETH_TYPE_RARP)) {
         const struct arp_eth_header *arp = pull_arp(&b);
         if (arp && arp->ar_hrd == htons(1)
             && arp->ar_pro == htons(ETH_TYPE_IP)

diff --git a/lib/flow.h b/lib/flow.h
@@ -123,6 +123,8 @@ struct flow_metadata {
 
 void flow_extract(struct ofpbuf *, uint32_t priority, uint32_t mark,
                   const struct flow_tnl *, uint16_t in_port, struct flow *);
+void flow_extract_l3_onwards(struct ofpbuf *, struct flow *,
+                             ovs_be16 dl_type);
 void flow_zero_wildcards(struct flow *, const struct flow_wildcards *);
 void flow_get_metadata(const struct flow *, struct flow_metadata *);