ICMP46 error: Clone first buffer instead of "truncating" original buffer

[vpp.git] / src / vnet / ip / icmp6.c

diff --git a/src/vnet/ip/icmp6.c b/src/vnet/ip/icmp6.c
index 37deb76..ff83a0c 100644 (file)
--- a/src/vnet/ip/icmp6.c
+++ b/src/vnet/ip/icmp6.c
@@ -493,15 +493,29 @@ ip6_icmp_error (vlib_main_t * vm,
 
       while (n_left_from > 0 && n_left_to_next > 0)
        {
-         u32 pi0 = from[0];
+         /*
+          * Duplicate first buffer and free the original chain.  Keep
+          * as much of the original packet as possible, within the
+          * minimum MTU. We chat "a little" here by keeping whatever
+          * is available in the first buffer.
+          */
+
+         u32 pi0 = ~0;
+         u32 org_pi0 = from[0];
          u32 next0 = IP6_ICMP_ERROR_NEXT_LOOKUP;
          u8 error0 = ICMP6_ERROR_NONE;
-         vlib_buffer_t *p0;
+         vlib_buffer_t *p0, *org_p0;
          ip6_header_t *ip0, *out_ip0;
          icmp46_header_t *icmp0;
          u32 sw_if_index0, if_add_index0;
          int bogus_length;
 
+         org_p0 = vlib_get_buffer (vm, org_pi0);
+         p0 = vlib_buffer_copy_no_chain (vm, org_p0, &pi0);
+         vlib_buffer_free_one (vm, org_pi0);
+         if (!p0 || pi0 == ~0) /* Out of buffers */
+           continue;
+
          /* Speculatively enqueue p0 to the current next frame */
          to_next[0] = pi0;
          from += 1;
@@ -509,37 +523,14 @@ ip6_icmp_error (vlib_main_t * vm,
          n_left_from -= 1;
          n_left_to_next -= 1;
 
-         p0 = vlib_get_buffer (vm, pi0);
          ip0 = vlib_buffer_get_current (p0);
          sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];
 
-         /* RFC4443 says to keep as much of the original packet as possible
-          * within the minimum MTU. We cheat "a little" here by keeping whatever fits
-          * in the first buffer, to be more efficient */
-         if (PREDICT_FALSE (p0->total_length_not_including_first_buffer))
-           {                   /* clear current_length of all other buffers in chain */
-             vlib_buffer_t *b = p0;
-             p0->total_length_not_including_first_buffer = 0;
-             while (b->flags & VLIB_BUFFER_NEXT_PRESENT)
-               {
-                 b = vlib_get_buffer (vm, b->next_buffer);
-                 b->current_length = 0;
-                 // XXX: Buffer leak???
-               }
-           }
-
          /* Add IP header and ICMPv6 header including a 4 byte data field */
-         int headroom = sizeof (ip6_header_t) + sizeof (icmp46_header_t) + 4;
-
-         /* Verify that we're not falling off the edge */
-         if (p0->current_data - headroom < -VLIB_BUFFER_PRE_DATA_SIZE)
-           {
-             next0 = IP6_ICMP_ERROR_NEXT_DROP;
-             error0 = ICMP6_ERROR_DROP;
-             goto error;
-           }
+         vlib_buffer_advance (p0,
+                              -(sizeof (ip6_header_t) +
+                                sizeof (icmp46_header_t) + 4));
 
-         vlib_buffer_advance (p0, -headroom);
          vnet_buffer (p0)->sw_if_index[VLIB_TX] = ~0;
          p0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
          p0->current_length =
@@ -571,7 +562,6 @@ ip6_icmp_error (vlib_main_t * vm,
            {
              next0 = IP6_ICMP_ERROR_NEXT_DROP;
              error0 = ICMP6_ERROR_DROP;
-             goto error;
            }
 
          /* Fill icmp header fields */
@@ -588,7 +578,6 @@ ip6_icmp_error (vlib_main_t * vm,
          if (error0 == ICMP6_ERROR_NONE)
            error0 = icmp6_icmp_type_to_error (icmp0->type);
 
-       error:
          vlib_error_count (vm, node->node_index, error0, 1);
 
          /* Verify speculative enqueue, maybe switch current next frame */