udp session: allow dgram ip fragmentation

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Ida8f9e759b4990ea6e34e71dc45bdb3b5eabc27f

1 files changed, 26 insertions, 17 deletions

diff --git a/src/vnet/ip/ip4.h b/src/vnet/ip/ip4.h
index a7ed5c26690..6e13cc8ea3e 100644
--- a/src/vnet/ip/ip4.h
+++ b/src/vnet/ip/ip4.h
@@ -363,23 +363,10 @@ u32 ip4_tcp_udp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0);
 
 #define IP_DF 0x4000		/* don't fragment */
 
-/**
- * Push IPv4 header to buffer
- *
- * This does not support fragmentation.
- *
- * @param vm - vlib_main
- * @param b - buffer to write the header to
- * @param src - source IP
- * @param dst - destination IP
- * @param prot - payload proto
- *
- * @return - pointer to start of IP header
- */
 always_inline void *
-vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
-		      ip4_address_t * src, ip4_address_t * dst, int proto,
-		      u8 csum_offload)
+vlib_buffer_push_ip4_custom (vlib_main_t * vm, vlib_buffer_t * b,
+			     ip4_address_t * src, ip4_address_t * dst,
+			     int proto, u8 csum_offload, u8 is_df)
 {
   ip4_header_t *ih;
 
@@ -391,7 +378,7 @@ vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
   ih->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b));
 
   /* No fragments */
-  ih->flags_and_fragment_offset = clib_host_to_net_u16 (IP_DF);
+  ih->flags_and_fragment_offset = is_df ? clib_host_to_net_u16 (IP_DF) : 0;
   ih->ttl = 255;
   ih->protocol = proto;
   ih->src_address.as_u32 = src->as_u32;
@@ -412,6 +399,28 @@ vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
   return ih;
 }
 
+/**
+ * Push IPv4 header to buffer
+ *
+ * This does not support fragmentation.
+ *
+ * @param vm - vlib_main
+ * @param b - buffer to write the header to
+ * @param src - source IP
+ * @param dst - destination IP
+ * @param prot - payload proto
+ *
+ * @return - pointer to start of IP header
+ */
+always_inline void *
+vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
+		      ip4_address_t * src, ip4_address_t * dst, int proto,
+		      u8 csum_offload)
+{
+  return vlib_buffer_push_ip4_custom (vm, b, src, dst, proto, csum_offload,
+				      1 /* is_df */ );
+}
+
 always_inline u32
 vlib_buffer_get_ip4_fib_index (vlib_buffer_t * b)
 {