From 4d333e6cd762b62ce702525e9fd0c76aac678324 Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Wed, 15 Jul 2020 23:02:09 +0200 Subject: [PATCH] Add a new PMTU discovery test. Use the ability to open multiple MeshLink instances from the same program into multiple namespaces. This avoids the need to communicate between multiple programs. --- test/Makefile.am | 5 ++ test/pmtu-setup | 63 +++++++++++++++ test/pmtu.c | 203 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 271 insertions(+) create mode 100755 test/pmtu-setup create mode 100644 test/pmtu.c diff --git a/test/Makefile.am b/test/Makefile.am index 688d8b7d..b359749e 100644 --- a/test/Makefile.am +++ b/test/Makefile.am @@ -25,6 +25,7 @@ TESTS = \ metering-slowping \ metering-tcponly \ meta-connections \ + pmtu \ sign-verify \ storage-policy \ trio \ @@ -73,6 +74,7 @@ check_PROGRAMS = \ metering-slowping \ metering-tcponly \ meta-connections \ + pmtu \ sign-verify \ storage-policy \ stream \ @@ -167,6 +169,9 @@ metering_tcponly_LDADD = $(top_builddir)/src/libmeshlink.la meta_connections_SOURCES = meta-connections.c netns_utils.c netns_utils.h utils.c utils.h meta_connections_LDADD = $(top_builddir)/src/libmeshlink.la +pmtu_SOURCES = pmtu.c utils.c utils.h +pmtu_LDADD = $(top_builddir)/src/libmeshlink.la + sign_verify_SOURCES = sign-verify.c utils.c utils.h sign_verify_LDADD = $(top_builddir)/src/libmeshlink.la diff --git a/test/pmtu-setup b/test/pmtu-setup new file mode 100755 index 00000000..41d03044 --- /dev/null +++ b/test/pmtu-setup @@ -0,0 +1,63 @@ +#!/bin/bash +set -e + +# Require root permissions +test "$(id -u)" = "0" || exit 77 + +prefix="pmtu_" + +# (Re)create the network namespaces we are going to use +for ns in n nn p pn r; do + ip netns delete ${prefix}${ns} 2>/dev/null || true + ip netns add ${prefix}${ns} + ip netns exec ${prefix}${ns} ip link set dev lo up +done + +# (Re)create the WAN bridge +ip link del ${prefix}br0 2>/dev/null || true +ip link add ${prefix}br0 type bridge +ip link set dev ${prefix}br0 up + +# Set up the public interfaces of the nats and relay, and connect them to the bridge +for ns in nn pn r; do + ip link del ${prefix}${ns}_p0 2>/dev/null || true + ip link del ${prefix}${ns}_e0 2>/dev/null || true + ip link add ${prefix}${ns}_e0 type veth peer name ${prefix}${ns}_p0 + ip link set ${prefix}${ns}_e0 netns ${prefix}${ns} name eth0 + ip link set ${prefix}${ns}_p0 master ${prefix}br0 up +done + +# Set up the LAN interfaces +for ns in n p; do + ip link add ${prefix}${ns}_e0 type veth peer name ${prefix}${ns}n_e1 + ip link set ${prefix}${ns}_e0 netns ${prefix}${ns} name eth0 + ip link set ${prefix}${ns}n_e1 netns ${prefix}${ns}n name eth1 + ip netns exec ${prefix}${ns} iptables -I INPUT -p tcp -s 203.0.113.2 -j DROP + ip netns exec ${prefix}${ns} iptables -I INPUT -p tcp -s 203.0.113.3 -j DROP +done + +# Configure the IP addresses of all interfaces +while read ns iface addr gw; do + ip netns exec ${prefix}${ns} ip addr add ${addr} dev ${iface} + ip netns exec ${prefix}${ns} ip link set dev ${iface} up + if [ -n "${gw}" ]; then + ip netns exec ${prefix}${ns} ip route add default via ${gw} + fi +done << EOF +n eth0 192.168.1.2/24 192.168.1.1 +nn eth0 203.0.113.2/24 +nn eth1 192.168.1.1/24 +p eth0 192.168.1.2/24 192.168.1.1 +pn eth0 203.0.113.3/24 +pn eth1 192.168.1.1/24 +r eth0 203.0.113.1/24 203.0.113.254 +EOF + +# Enable NAT +while read ns wan_addr; do + ip netns exec ${prefix}${ns} iptables -t nat -A PREROUTING -i eth0 -j DNAT --to-destination 192.168.1.2 + ip netns exec ${prefix}${ns} iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source ${wan_addr} +done << EOF +nn 203.0.113.2 +pn 203.0.113.3 +EOF diff --git a/test/pmtu.c b/test/pmtu.c new file mode 100644 index 00000000..cb39d4bc --- /dev/null +++ b/test/pmtu.c @@ -0,0 +1,203 @@ +#ifndef NDEBUG +#undef NDEBUG +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "meshlink.h" +#include "utils.h" + +#define nnodes 3 + +static const struct info { + const char *name; + const char *confdir; + const char *netns; + dev_class_t devclass; +} nodes[nnodes] = { + {"relay", "pmtu_conf.1", "/run/netns/pmtu_r", DEV_CLASS_BACKBONE}, + {"peer", "pmtu_conf.2", "/run/netns/pmtu_p", DEV_CLASS_STATIONARY}, + {"nut", "pmtu_conf.3", "/run/netns/pmtu_n", DEV_CLASS_STATIONARY}, +}; + +static struct state { + meshlink_handle_t *mesh; + int netns; + struct sync_flag up_flag; + int pmtu; + int probe_count; + int probe_bytes; +} states[nnodes]; + +static void relay_up_cb(meshlink_handle_t *mesh, meshlink_node_t *node, bool reachable) { + struct state *state = mesh->priv; + + // Check that we are connected to another peer besides the relay + if(reachable && node != meshlink_get_self(mesh) && strcmp(node->name, "relay")) { + set_sync_flag(&state->up_flag, true); + meshlink_set_node_status_cb(mesh, NULL); + } +} + +static void receive_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, const void *data, size_t len) { + if(!data && !len) { + meshlink_channel_close(mesh, channel); + } +} + +static bool accept_cb(meshlink_handle_t *mesh, meshlink_channel_t *channel, uint16_t port, const void *data, size_t len) { + (void)port; + (void)data; + (void)len; + meshlink_set_channel_receive_cb(mesh, channel, receive_cb); + return true; +} + +static void parse_log_cb(meshlink_handle_t *mesh, meshlink_log_level_t level, const char *text) { + if(level >= MESHLINK_INFO) { + log_cb(mesh, level, text); + } + + struct state *state = mesh->priv; + + if(state->pmtu != 0) { + return; + } + + int len; + char name[10] = ""; + + if(sscanf(text, "Sending UDP probe length %d to %9s", &len, name) == 2 || sscanf(text, "Got PMTU probe length %d from %s", &len, name) == 2) { + if(!strcmp(name, "nut")) { + state->probe_count++; + state->probe_bytes += len; + } + } else if(sscanf(text, "Fixing PMTU of %9s to %d", name, &len) == 2) { + if(!strcmp(name, "nut")) { + state->pmtu = len; + } + } +} + +static void wait_for_pmtu(void) { + // Set up a channel from peer to nut + meshlink_set_channel_accept_cb(states[2].mesh, accept_cb); + meshlink_channel_t *channel = meshlink_channel_open(states[1].mesh, meshlink_get_node(states[1].mesh, nodes[2].name), 1, NULL, NULL, 0); + assert(channel); + + // While sending regular data, wait for PMTU discovery to finish + for(int i = 0; i < 30; i++) { + sleep(1); + + if(states[1].pmtu) { + break; + } + + assert(meshlink_channel_send(states[1].mesh, channel, "ping", 4) == 4); + } + + meshlink_channel_close(states[1].mesh, channel); +} + +static void start_peer_nut(void) { + // Start peer and nut + for(int i = 1; i < nnodes; i++) { + meshlink_set_node_status_cb(states[i].mesh, relay_up_cb); + assert(meshlink_start(states[i].mesh)); + } + + // Wait for the peer and nut to see each other + for(int i = 1; i < nnodes; i++) { + assert(wait_sync_flag(&states[i].up_flag, 5)); + } +} + +static void stop_peer_nut(void) { + // Stop peer and nut, reset counters + for(int i = 1; i < nnodes; i++) { + meshlink_stop(states[i].mesh); + states[i].up_flag.flag = false; + states[i].pmtu = 0; + states[i].probe_count = 0; + states[i].probe_bytes = 0; + } +} + +int main(void) { + // This test requires root access due to the use of network namespaces + if(getuid() != 0) { + return 77; + } + + // Set up namespaces + assert(system("./pmtu-setup") == 0); + + // Bring up the nodes + for(int i = 0; i < nnodes; i++) { + assert(meshlink_destroy(nodes[i].confdir)); + + // Open the network namespace + states[i].netns = open(nodes[i].netns, O_RDONLY); + assert(states[i].netns != -1); + + // Open the MeshLink instance + meshlink_open_params_t *params; + assert(params = meshlink_open_params_init(nodes[i].confdir, nodes[i].name, "pmtu", nodes[i].devclass)); + assert(meshlink_open_params_set_netns(params, states[i].netns)); + assert(states[i].mesh = meshlink_open_ex(params)); + free(params); + + states[i].mesh->priv = &states[i]; + meshlink_enable_discovery(states[i].mesh, false); + init_sync_flag(&states[i].up_flag); + + meshlink_set_log_cb(states[i].mesh, MESHLINK_DEBUG, parse_log_cb); + + // Link the relay node to the other nodes + if(i > 0) { + link_meshlink_pair(states[0].mesh, states[i].mesh); + } + } + + // Start the relay + assert(meshlink_start(states[0].mesh)); + + // Start peers and wait for them to connect + start_peer_nut(); + + // Wait for PMTU discovery to finish + wait_for_pmtu(); + + assert(states[1].pmtu >= 1400 && states[1].pmtu <= 1500); + assert(states[1].probe_count <= 10); + assert(states[1].probe_bytes <= 1500 * 10); + + // Drop the MTU to 800 + stop_peer_nut(); + + assert(system("ip netns exec pmtu_p ip link set eth0 mtu 800") == 0); + assert(system("ip netns exec pmtu_n ip link set eth0 mtu 800") == 0); + + // Workaround for autoconnect algorithm throttling reconnects + sleep(15); + + start_peer_nut(); + wait_for_pmtu(); + + assert(states[1].pmtu >= 700 && states[1].pmtu <= 800); + assert(states[1].probe_count <= 20); + assert(states[1].probe_bytes <= 800 * 20); + + // Cleanup + for(int i = 0; i < nnodes; i++) { + meshlink_close(states[i].mesh); + } +} -- 2.39.5