ip6: answer to router sollicit message

Upon reception of a router sollicit message, trigger the existing timer to send immediately a router advertismement packet. Add relevant test: as the same mac address is defined for 2 interfaces in the 2 namespaces, the same link local ip address will be generated and used by linux. Update github workflow and doc to reflect the addition of 'ndisc6' as a test tool. Signed-off-by: Christophe Fontaine <[email protected]>
DPDK · Jan 17, 2025 · 2e45b6c · 2e45b6c
1 parent 65aa832
commit 2e45b6c
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Showing 9 changed files with 331 additions and 172 deletions.
diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
@@ -66,7 +66,8 @@ jobs:
           sudo NEEDRESTART_MODE=l apt-get install -qy --no-install-recommends \
             git socat tcpdump traceroute graphviz \
             iproute2 iputils-ping libasan8 libedit2 \
-            libevent-2.1-7t64 libsmartcols1 libnuma1
+            libevent-2.1-7t64 libsmartcols1 libnuma1 \
+            ndisc6
       - uses: actions/checkout@v4
         with:
           persist-credentials: false

diff --git a/README.md b/README.md
@@ -237,17 +237,28 @@ image.
 ```sh
 dnf install gcc git make meson ninja-build pkgconf scdoc python3-pyelftools \
         libcmocka-devel libedit-devel libevent-devel numactl-devel \
-        libsmartcols-devel libarchive-devel rdma-core-devel \
-        clang-tools-extra jq curl traceroute graphviz
+        libsmartcols-devel libarchive-devel rdma-core-devel
 ```
 
 or
 
 ```sh
 apt install git gcc make meson ninja-build pkgconf scdoc python3-pyelftools \
         libcmocka-dev libedit-dev libevent-dev libnuma-dev \
-        libsmartcols-dev libarchive-dev libibverbs-dev \
-        clang-format jq curl traceroute graphviz
+        libsmartcols-dev libarchive-dev libibverbs-dev
+```
+
+### Install optional dependencies
+In order to run "make smoke-test" and "make update-graph", you'll need additional packages:
+
+```sh
+dnf install clang-tools-extra jq curl traceroute graphviz ndisc6
+```
+
+or
+
+```sh
+apt install clang-format jq curl traceroute graphviz ndisc6
 ```
 
 ### Build

diff --git a/docs/graph.svg b/docs/graph.svg
diff --git a/modules/ip6/control/gr_ip6_control.h b/modules/ip6/control/gr_ip6_control.h
@@ -26,6 +26,7 @@ struct nexthop *ip6_nexthop_new(uint16_t vrf_id, uint16_t iface_id, const struct
 
 void ip6_nexthop_unreachable_cb(struct rte_mbuf *m);
 void ndp_probe_input_cb(struct rte_mbuf *m);
+void ndp_router_sollicit_input_cb(struct rte_mbuf *m);
 
 int ip6_route_insert(uint16_t vrf_id, uint16_t iface_id, const struct rte_ipv6_addr *, uint8_t prefixlen, struct nexthop *);
 int ip6_route_delete(

diff --git a/modules/ip6/control/router_advert.c b/modules/ip6/control/router_advert.c
@@ -43,6 +43,11 @@ static struct api_out iface_ra_clear(const void *request, void ** /*response*/)
 	return api_out(0, 0);
 }
 
+void ndp_router_sollicit_input_cb(struct rte_mbuf *m) {
+	rte_pktmbuf_free(m);
+	event_active(ra_ctx.timer, 0, 0);
+}
+
 static void build_ra_packet(struct rte_mbuf *m, struct rte_ipv6_addr *srcv6) {
 	struct rte_ipv6_addr dst = RTE_IPV6_ADDR_ALLNODES_LINK_LOCAL;
 	struct rte_ipv6_addr src = *srcv6;

diff --git a/modules/ip6/datapath/icmp6_input.c b/modules/ip6/datapath/icmp6_input.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 // Copyright (c) 2024 Robin Jarry
 
+#include <gr_control_output.h>
 #include <gr_datapath.h>
 #include <gr_graph.h>
 #include <gr_icmp6.h>
@@ -19,6 +20,7 @@ enum {
 	ICMP6_OUTPUT = 0,
 	NEIGH_SOLICIT,
 	NEIGH_ADVERT,
+	ROUTER_SOLICIT,
 	BAD_CHECKSUM,
 	INVALID,
 	UNSUPPORTED,
@@ -64,6 +66,8 @@ icmp6_input_process(struct rte_graph *graph, struct rte_node *node, void **objs,
 			next = NEIGH_ADVERT;
 			break;
 		case ICMP6_TYPE_ROUTER_SOLICIT:
+			next = ROUTER_SOLICIT;
+			break;
 		case ICMP6_TYPE_ROUTER_ADVERT:
 		default:
 			next = UNSUPPORTED;
@@ -89,6 +93,7 @@ static struct rte_node_register icmp6_input_node = {
 		[ICMP6_OUTPUT] = "icmp6_output",
 		[NEIGH_SOLICIT] = "ndp_ns_input",
 		[NEIGH_ADVERT] = "ndp_na_input",
+		[ROUTER_SOLICIT] = "ndp_rs_input",
 		[BAD_CHECKSUM] = "icmp6_input_bad_checksum",
 		[INVALID] = "icmp6_input_invalid",
 		[UNSUPPORTED] = "icmp6_input_unsupported",

diff --git a/modules/ip6/datapath/meson.build b/modules/ip6/datapath/meson.build
@@ -13,5 +13,6 @@ src += files(
   'ndp_na_input.c',
   'ndp_ns_input.c',
   'ndp_ns_output.c',
+  'ndp_rs_input.c',
 )
 inc += include_directories('.')
diff --git a/modules/ip6/datapath/ndp_rs_input.c b/modules/ip6/datapath/ndp_rs_input.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2025 Christophe Fontaine
+
+#include <gr_control_output.h>
+#include <gr_graph.h>
+#include <gr_icmp6.h>
+#include <gr_ip6_control.h>
+#include <gr_ip6_datapath.h>
+#include <gr_log.h>
+#include <gr_mbuf.h>
+#include <gr_trace.h>
+
+#include <rte_byteorder.h>
+#include <rte_ether.h>
+#include <rte_graph_worker.h>
+#include <rte_ip6.h>
+
+enum {
+	CONTROL,
+	INVAL,
+	EDGE_COUNT,
+};
+
+static uint16_t ndp_rs_input_process(
+	struct rte_graph *graph,
+	struct rte_node *node,
+	void **objs,
+	uint16_t nb_objs
+) {
+	struct control_output_mbuf_data *co;
+	struct ip6_local_mbuf_data *d;
+	struct rte_mbuf *mbuf;
+	struct icmp6 *icmp6;
+	rte_edge_t next;
+
+#define ASSERT_NDP(condition)                                                                      \
+	do {                                                                                       \
+		if (!(condition)) {                                                                \
+			next = INVAL;                                                              \
+			goto next;                                                                 \
+		}                                                                                  \
+	} while (0)
+
+	for (uint16_t i = 0; i < nb_objs; i++) {
+		mbuf = objs[i];
+
+		d = ip6_local_mbuf_data(mbuf);
+		icmp6 = rte_pktmbuf_mtod(mbuf, struct icmp6 *);
+
+		// Validation of Router Solicitations
+		// https://www.rfc-editor.org/rfc/rfc4861#section-6.1.1
+		//
+		// - The IP Hop Limit field has a value of 255, i.e., the packet
+		//   could not possibly have been forwarded by a router.
+		ASSERT_NDP(d->hop_limit == 255);
+		// - ICMP Checksum is valid. (already checked in icmp6_input)
+		//
+		// - ICMP Code is 0.
+		ASSERT_NDP(icmp6->code == 0);
+		// - ICMP length (derived from the IP length) is 8 or more octets.
+		ASSERT_NDP(d->len >= 8);
+
+		next = CONTROL;
+		co = control_output_mbuf_data(mbuf);
+		co->callback = ndp_router_sollicit_input_cb;
+next:
+		if (gr_mbuf_is_traced(mbuf))
+			gr_mbuf_trace_add(mbuf, node, 0);
+		rte_node_enqueue_x1(graph, node, next, mbuf);
+	}
+
+	return nb_objs;
+}
+
+static struct rte_node_register node = {
+	.name = "ndp_rs_input",
+	.process = ndp_rs_input_process,
+	.nb_edges = EDGE_COUNT,
+	.next_nodes = {
+		[CONTROL] = "control_output",
+		[INVAL] = "ndp_rs_input_inval",
+	},
+};
+
+static struct gr_node_info info = {
+	.node = &node,
+	.trace_format = (gr_trace_format_cb_t)trace_icmp6_format,
+};
+
+GR_NODE_REGISTER(info);
+
+GR_DROP_REGISTER(ndp_rs_input_inval);
diff --git a/smoke/ip6_rs_ra_test.sh b/smoke/ip6_rs_ra_test.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2025 Christophe Fontaine
+
+. $(dirname $0)/_init.sh
+
+p1=${run_id}1
+
+grcli add interface port $p1 devargs net_tap0,iface=$p1 mac d2:f0:0c:ba:a4:11
+grcli add ip6 address fd00:ba4:1::1/64 iface $p1
+
+for n in 1; do
+	p=$run_id$n
+	ip netns add $p
+	echo ip netns del $p >> $tmp/cleanup
+	ip link set $p netns $p
+	ip -n $p link set $p address d2:ad:ca:ca:a4:1$n
+	ip -n $p link set $p up
+	ip -n $p addr add fd00:ba4:$n::2/64 dev $p
+	ip -n $p addr show
+done
+
+sleep 3  # wait for DAD
+
+ip netns exec $p1 rdisc6 $p1