--- /dev/null
+/*
+ * mss_clamp_node.c - Node implementing TCP MSS clamping
+ *
+ * Copyright (c) 2018 Cisco and/or its affiliates
+ * 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <mss_clamp/mss_clamp.h>
+#include <mss_clamp/mss_clamp.api_enum.h>
+#include <vnet/fib/fib_types.h>
+#include <vnet/feature/feature.h>
+#include <vnet/ip/ip4.h>
+#include <vnet/ip/ip6.h>
+
+extern vlib_node_registration_t mssc_ip4_in_node, mssc_ip4_out_node;
+extern vlib_node_registration_t mssc_ip6_in_node, mssc_ip6_out_node;
+
+typedef struct mssc_trace_t_
+{
+ u32 max_mss;
+ u32 clamped;
+} mssc_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_mssc_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 *);
+ mssc_trace_t *t = va_arg (*args, mssc_trace_t *);
+
+ s = format (s, "max mss: %d clamped: %d", t->max_mss, t->clamped);
+ return s;
+}
+
+typedef enum
+{
+ MSSC_NEXT_DROP,
+ MSSC_N_NEXT,
+} mssc_next_t;
+
+/*
+ * fixup the maximum segment size if it's a syn packet
+ * return 1 if the mss was changed otherwise 0
+ */
+always_inline u32
+mssc_mss_fixup (vlib_buffer_t *b0, tcp_header_t *tcp0, u16 max_mss0)
+{
+ ip_csum_t sum0;
+
+ if (PREDICT_FALSE (tcp_syn (tcp0)))
+ {
+ u8 opt_len, opts_len, kind;
+ const u8 *data;
+ u16 mss0, new_mss0;
+
+ opts_len = (tcp_doff (tcp0) << 2) - sizeof (tcp_header_t);
+ data = (const u8 *) (tcp0 + 1);
+
+ for (; opts_len > 0; opts_len -= opt_len, data += opt_len)
+ {
+ kind = data[0];
+
+ /* Get options length */
+ if (kind == TCP_OPTION_EOL)
+ break;
+ else if (kind == TCP_OPTION_NOOP)
+ {
+ opt_len = 1;
+ continue;
+ }
+ else
+ {
+ /* broken options */
+ if (opts_len < 2)
+ return 0;
+ opt_len = data[1];
+
+ /* weird option length */
+ if (opt_len < 2 || opt_len > opts_len)
+ return 0;
+ }
+
+ if (kind == TCP_OPTION_MSS)
+ {
+ mss0 = *(u16 *) (data + 2);
+ if (clib_net_to_host_u16 (mss0) > max_mss0)
+ {
+ new_mss0 = clib_host_to_net_u16 (max_mss0);
+ *((u16 *) (data + 2)) = new_mss0;
+ sum0 = tcp0->checksum;
+ sum0 = ip_csum_update (sum0, mss0, new_mss0, tcp_header_t,
+ checksum);
+ tcp0->checksum = ip_csum_fold (sum0);
+ return 1;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+always_inline uword
+mssc_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame,
+ vlib_dir_t dir, fib_protocol_t fproto)
+{
+ mssc_main_t *cm = &mssc_main;
+ vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
+ u16 nexts[VLIB_FRAME_SIZE], *next;
+ u32 n_left, *from;
+ u32 pkts_clamped = 0;
+
+ from = vlib_frame_vector_args (frame);
+ n_left = frame->n_vectors;
+ b = bufs;
+ next = nexts;
+
+ vlib_get_buffers (vm, from, bufs, n_left);
+
+ while (n_left >= 4)
+ {
+ u32 sw_if_index0, sw_if_index1;
+ const u8 *h0, *h1;
+ u32 clamped0, clamped1;
+
+ /* Prefetch next iteration. */
+ {
+ vlib_prefetch_buffer_header (b[2], LOAD);
+ vlib_prefetch_buffer_header (b[3], LOAD);
+ vlib_prefetch_buffer_data (b[2], LOAD);
+ vlib_prefetch_buffer_data (b[3], LOAD);
+ }
+
+ sw_if_index0 = vnet_buffer (b[0])->sw_if_index[dir];
+ sw_if_index1 = vnet_buffer (b[1])->sw_if_index[dir];
+ clamped0 = clamped1 = 0;
+
+ /* speculatively enqueue b0 to the current next frame */
+ vnet_feature_next_u16 (&next[0], b[0]);
+ vnet_feature_next_u16 (&next[1], b[1]);
+
+ h0 = (u8 *) vlib_buffer_get_current (b[0]);
+ h1 = (u8 *) vlib_buffer_get_current (b[1]);
+ if (VLIB_TX == dir)
+ {
+ h0 += vnet_buffer (b[0])->ip.save_rewrite_length;
+ h1 += vnet_buffer (b[1])->ip.save_rewrite_length;
+ }
+
+ if (FIB_PROTOCOL_IP4 == fproto)
+ {
+ ip4_header_t *ip0 = (ip4_header_t *) h0;
+ ip4_header_t *ip1 = (ip4_header_t *) h1;
+
+ if (IP_PROTOCOL_TCP == ip0->protocol)
+ {
+ clamped0 = mssc_mss_fixup (b[0], ip4_next_header (ip0),
+ cm->max_mss4[sw_if_index0]);
+ }
+ if (IP_PROTOCOL_TCP == ip1->protocol)
+ {
+ clamped1 = mssc_mss_fixup (b[1], ip4_next_header (ip1),
+ cm->max_mss4[sw_if_index1]);
+ }
+ }
+ else if (FIB_PROTOCOL_IP6 == fproto)
+ {
+ ip6_header_t *ip0 = (ip6_header_t *) h0;
+ ip6_header_t *ip1 = (ip6_header_t *) h1;
+
+ if (IP_PROTOCOL_TCP == ip0->protocol)
+ {
+ clamped0 = mssc_mss_fixup (b[0], ip6_next_header (ip0),
+ cm->max_mss6[sw_if_index0]);
+ }
+ if (IP_PROTOCOL_TCP == ip1->protocol)
+ {
+ clamped1 = mssc_mss_fixup (b[1], ip6_next_header (ip1),
+ cm->max_mss6[sw_if_index1]);
+ }
+ }
+
+ pkts_clamped += clamped0 + clamped1;
+
+ if (PREDICT_FALSE (node->flags & VLIB_NODE_FLAG_TRACE))
+ {
+ if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ mssc_trace_t *t;
+
+ t = vlib_add_trace (vm, node, b[0], sizeof (*t));
+ t->max_mss = (FIB_PROTOCOL_IP4 == fproto) ?
+ cm->max_mss4[sw_if_index0] :
+ cm->max_mss6[sw_if_index0];
+ t->clamped = clamped0;
+ }
+ if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ mssc_trace_t *t;
+
+ t = vlib_add_trace (vm, node, b[1], sizeof (*t));
+ t->max_mss = (FIB_PROTOCOL_IP4 == fproto) ?
+ cm->max_mss4[sw_if_index1] :
+ cm->max_mss6[sw_if_index1];
+ t->clamped = clamped1;
+ }
+ }
+
+ b += 2;
+ next += 2;
+ n_left -= 2;
+ }
+
+ while (n_left > 0)
+ {
+ u32 sw_if_index0;
+ const u8 *h0;
+ u32 clamped0;
+
+ sw_if_index0 = vnet_buffer (b[0])->sw_if_index[dir];
+ clamped0 = 0;
+
+ /* speculatively enqueue b0 to the current next frame */
+ vnet_feature_next_u16 (&next[0], b[0]);
+
+ h0 = (u8 *) vlib_buffer_get_current (b[0]);
+ if (VLIB_TX == dir)
+ h0 += vnet_buffer (b[0])->ip.save_rewrite_length;
+
+ if (FIB_PROTOCOL_IP4 == fproto)
+ {
+ ip4_header_t *ip0 = (ip4_header_t *) h0;
+
+ if (IP_PROTOCOL_TCP == ip0->protocol)
+ {
+ clamped0 = mssc_mss_fixup (b[0], ip4_next_header (ip0),
+ cm->max_mss4[sw_if_index0]);
+ }
+ }
+ else if (FIB_PROTOCOL_IP6 == fproto)
+ {
+ ip6_header_t *ip0 = (ip6_header_t *) h0;
+
+ if (IP_PROTOCOL_TCP == ip0->protocol)
+ {
+ clamped0 = mssc_mss_fixup (b[0], ip6_next_header (ip0),
+ cm->max_mss6[sw_if_index0]);
+ }
+ }
+
+ pkts_clamped += clamped0;
+
+ if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
+ (b[0]->flags & VLIB_BUFFER_IS_TRACED)))
+ {
+ mssc_trace_t *t;
+
+ t = vlib_add_trace (vm, node, b[0], sizeof (*t));
+ t->max_mss = (FIB_PROTOCOL_IP4 == fproto) ?
+ cm->max_mss4[sw_if_index0] :
+ cm->max_mss6[sw_if_index0];
+ t->clamped = clamped0;
+ }
+
+ b++;
+ next++;
+ n_left--;
+ }
+
+ vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
+ vlib_node_increment_counter (vm, node->node_index, MSS_CLAMP_ERROR_CLAMPED,
+ pkts_clamped);
+
+ return frame->n_vectors;
+}
+
+static uword
+mssc_ip4_in (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+ return (mssc_inline (vm, node, frame, VLIB_RX, FIB_PROTOCOL_IP4));
+}
+
+static uword
+mssc_ip4_out (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+ return (mssc_inline (vm, node, frame, VLIB_TX, FIB_PROTOCOL_IP4));
+}
+
+static uword
+mssc_ip6_in (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+ return (mssc_inline (vm, node, frame, VLIB_RX, FIB_PROTOCOL_IP6));
+}
+
+static uword
+mssc_ip6_out (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+{
+ return (mssc_inline (vm, node, frame, VLIB_TX, FIB_PROTOCOL_IP6));
+}
+
+VLIB_REGISTER_NODE (mssc_ip4_in_node) =
+{
+ .function = mssc_ip4_in,
+ .name = "tcp-mss-clamping-ip4-in",
+ .vector_size = sizeof (u32),
+ .format_trace = format_mssc_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = MSS_CLAMP_N_ERROR,
+ .error_counters = mss_clamp_error_counters,
+
+ .n_next_nodes = MSSC_N_NEXT,
+ .next_nodes = {
+ [MSSC_NEXT_DROP] = "error-drop",
+ },
+};
+
+VLIB_REGISTER_NODE (mssc_ip4_out_node) =
+{
+ .function = mssc_ip4_out,
+ .name = "tcp-mss-clamping-ip4-out",
+ .vector_size = sizeof (u32),
+ .format_trace = format_mssc_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = MSS_CLAMP_N_ERROR,
+ .error_counters = mss_clamp_error_counters,
+
+ .n_next_nodes = MSSC_N_NEXT,
+ .next_nodes = {
+ [MSSC_NEXT_DROP] = "error-drop",
+ },
+};
+
+VLIB_REGISTER_NODE (mssc_ip6_in_node) =
+{
+ .function = mssc_ip6_in,
+ .name = "tcp-mss-clamping-ip6-in",
+ .vector_size = sizeof (u32),
+ .format_trace = format_mssc_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = MSS_CLAMP_N_ERROR,
+ .error_counters = mss_clamp_error_counters,
+
+ .n_next_nodes = MSSC_N_NEXT,
+ .next_nodes = {
+ [MSSC_NEXT_DROP] = "error-drop",
+ },
+};
+
+VLIB_REGISTER_NODE (mssc_ip6_out_node) =
+{
+ .function = mssc_ip6_out,
+ .name = "tcp-mss-clamping-ip6-out",
+ .vector_size = sizeof (u32),
+ .format_trace = format_mssc_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = MSS_CLAMP_N_ERROR,
+ .error_counters = mss_clamp_error_counters,
+
+ .n_next_nodes = MSSC_N_NEXT,
+ .next_nodes = {
+ [MSSC_NEXT_DROP] = "error-drop",
+ },
+};
+
+VNET_FEATURE_INIT (mssc_ip4_in_feat, static) = {
+ .arc_name = "ip4-unicast",
+ .node_name = "tcp-mss-clamping-ip4-in",
+ .runs_after = VNET_FEATURES ("ip4-policer-classify"),
+};
+
+VNET_FEATURE_INIT (mssc_ip4_out_feat, static) = {
+ .arc_name = "ip4-output",
+ .node_name = "tcp-mss-clamping-ip4-out",
+};
+
+VNET_FEATURE_INIT (mssc_ip6_in_feat, static) = {
+ .arc_name = "ip6-unicast",
+ .node_name = "tcp-mss-clamping-ip6-in",
+ .runs_after = VNET_FEATURES ("ip6-policer-classify"),
+};
+
+VNET_FEATURE_INIT (mssc_ip6_out_feat, static) = {
+ .arc_name = "ip6-output",
+ .node_name = "tcp-mss-clamping-ip6-out",
+};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
Code Review / vpp.git / blobdiff