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authorNeale Ranns <neale@graphiant.com>2020-12-21 08:29:34 +0000
committerOle Tr�an <otroan@employees.org>2021-02-15 17:27:48 +0000
commit8f5fef2c78b95de1a636ce27111722b71702212a (patch)
treea0ebd0189969ccae1f0bdd7c1a9c18dd7a066f2e /src/vnet/ip/ip_path_mtu_node.c
parent54be0cc044f445853fae7b8995c477605250af16 (diff)
ip: Path MTU
Type: feature Support setting the MTU for a peer on an interface. The minimum value of the path and interface MTU is used at forwarding time. the path MTU is specified for a given peer, by address and table-ID. In the forwarding plane the MTU is enfored either: 1 - if the peer is attached, then the MTU is set on the peer's adjacency 2 - if the peer is not attached, it is remote, then a DPO is added to the peer's FIB entry to perform the necessary fragmentation. Signed-off-by: Neale Ranns <neale@graphiant.com> Change-Id: I8b9ea6a07868b50e97e2561f18d9335407dea7ae
Diffstat (limited to 'src/vnet/ip/ip_path_mtu_node.c')
-rw-r--r--src/vnet/ip/ip_path_mtu_node.c206
1 files changed, 206 insertions, 0 deletions
diff --git a/src/vnet/ip/ip_path_mtu_node.c b/src/vnet/ip/ip_path_mtu_node.c
new file mode 100644
index 00000000000..b13f9de849c
--- /dev/null
+++ b/src/vnet/ip/ip_path_mtu_node.c
@@ -0,0 +1,206 @@
+/*
+ *------------------------------------------------------------------
+ * ip_path_mtu.c
+ *
+ * Copyright (c) 2020 Graphiant.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <vnet/ip/ip_path_mtu.h>
+#include <vnet/ip/ip_frag.h>
+
+typedef enum
+{
+ IP_PMTU_DROP,
+ IP_PMTU_N_NEXT,
+} ip_pmtu_next_t;
+
+typedef struct ip_pmtu_trace_t_
+{
+ u16 pmtu;
+ u16 packet_size;
+} ip_pmtu_trace_t;
+
+static u8 *
+format_ip_pmtu_trace (u8 *s, va_list *args)
+{
+ CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+ CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+ ip_pmtu_trace_t *t = va_arg (*args, ip_pmtu_trace_t *);
+
+ s = format (s, "path mtu:%d packet size:%d", t->pmtu, t->packet_size);
+
+ return s;
+}
+
+static inline uword
+ip_pmtu_dpo_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+ vlib_frame_t *frame, ip_address_family_t af)
+{
+ u32 n_left_from, *from, next_index, *to_next, n_left_to_next;
+ u32 frag_sent = 0, small_packets = 0;
+
+ from = vlib_frame_vector_args (frame);
+ n_left_from = frame->n_vectors;
+ next_index = node->cached_next_index;
+
+ u32 *buffer = 0;
+
+ while (n_left_from > 0)
+ {
+ vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+ while (n_left_from > 0 && n_left_to_next > 0)
+ {
+ const ip_pmtu_dpo_t *ipm0;
+ u32 pi0, *frag_from, frag_left;
+ vlib_buffer_t *p0;
+ ip_frag_error_t error0;
+ u16 next0;
+
+ /*
+ * Note: The packet is not enqueued now. It is instead put
+ * in a vector where other fragments will be put as well.
+ */
+ pi0 = from[0];
+ from += 1;
+ n_left_from -= 1;
+
+ p0 = vlib_get_buffer (vm, pi0);
+ ipm0 = ip_pmtu_dpo_get (vnet_buffer (p0)->ip.adj_index[VLIB_TX]);
+ vnet_buffer (p0)->ip.adj_index[VLIB_TX] = ipm0->ipm_dpo.dpoi_index;
+ next0 = ipm0->ipm_dpo.dpoi_next_node;
+
+ if (PREDICT_FALSE (p0->flags & VLIB_BUFFER_IS_TRACED))
+ {
+ ip_pmtu_trace_t *t;
+ t = vlib_add_trace (vm, node, p0, sizeof (*t));
+ t->pmtu = ipm0->ipm_pmtu;
+ t->packet_size = vlib_buffer_length_in_chain (vm, p0);
+ }
+
+ if (AF_IP6 == af)
+ error0 =
+ ip6_frag_do_fragment (vm, pi0, ipm0->ipm_pmtu, 0, &buffer);
+ else
+ error0 =
+ ip4_frag_do_fragment (vm, pi0, ipm0->ipm_pmtu, 0, &buffer);
+
+ if (AF_IP4 == af && error0 == IP_FRAG_ERROR_DONT_FRAGMENT_SET)
+ {
+ icmp4_error_set_vnet_buffer (
+ p0, ICMP4_destination_unreachable,
+ ICMP4_destination_unreachable_fragmentation_needed_and_dont_fragment_set,
+ ipm0->ipm_pmtu);
+ next0 = IP_FRAG_NEXT_ICMP_ERROR;
+ }
+ else
+ {
+ next0 =
+ (error0 == IP_FRAG_ERROR_NONE ? next0 : IP_FRAG_NEXT_DROP);
+ }
+
+ if (error0 == IP_FRAG_ERROR_NONE)
+ {
+ /* Free original buffer chain */
+ frag_sent += vec_len (buffer);
+ small_packets += (vec_len (buffer) == 1);
+ vlib_buffer_free_one (vm, pi0); /* Free original packet */
+ }
+ else
+ {
+ vlib_error_count (vm, node->node_index, error0, 1);
+ vec_add1 (buffer, pi0); /* Get rid of the original buffer */
+ }
+
+ /* Send fragments that were added in the frame */
+ frag_from = buffer;
+ frag_left = vec_len (buffer);
+
+ while (frag_left > 0)
+ {
+ while (frag_left > 0 && n_left_to_next > 0)
+ {
+ u32 i;
+ i = to_next[0] = frag_from[0];
+ frag_from += 1;
+ frag_left -= 1;
+ to_next += 1;
+ n_left_to_next -= 1;
+
+ vlib_get_buffer (vm, i)->error = node->errors[error0];
+ vlib_validate_buffer_enqueue_x1 (
+ vm, node, next_index, to_next, n_left_to_next, i, next0);
+ }
+ vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+ vlib_get_next_frame (vm, node, next_index, to_next,
+ n_left_to_next);
+ }
+ vec_reset_length (buffer);
+ }
+ vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+ }
+ vec_free (buffer);
+
+ return frame->n_vectors;
+}
+
+// clang-format off
+
+VLIB_NODE_FN (ip4_ip_pmtu_dpo_node) (vlib_main_t *vm,
+ vlib_node_runtime_t *node,
+ vlib_frame_t *from_frame)
+{
+ return (ip_pmtu_dpo_inline (vm, node, from_frame, 0));
+}
+
+VLIB_NODE_FN (ip6_ip_pmtu_dpo_node) (vlib_main_t *vm,
+ vlib_node_runtime_t *node,
+ vlib_frame_t *from_frame)
+{
+ return (ip_pmtu_dpo_inline (vm, node, from_frame, 1));
+}
+
+VLIB_REGISTER_NODE (ip4_ip_pmtu_dpo_node) = {
+ .name = "ip4-pmtu-dpo",
+ .vector_size = sizeof (u32),
+ .format_trace = format_ip_pmtu_trace,
+ .n_errors = 0,
+ .n_next_nodes = IP_PMTU_N_NEXT,
+ .next_nodes =
+ {
+ [IP_PMTU_DROP] = "ip4-drop",
+ }
+};
+VLIB_REGISTER_NODE (ip6_ip_pmtu_dpo_node) = {
+ .name = "ip6-pmtu-dpo",
+ .vector_size = sizeof (u32),
+ .format_trace = format_ip_pmtu_trace,
+ .n_errors = 0,
+ .n_next_nodes = IP_PMTU_N_NEXT,
+ .next_nodes =
+ {
+ [IP_PMTU_DROP] = "ip6-drop",
+ }
+};
+
+// clang-format on
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */