// SPDX-License-Identifier: GPL-2.0 #include #include #include #include #include "ip_check_defrag.skel.h" #include "ip_check_defrag_frags.h" /* * This selftest spins up a client and an echo server, each in their own * network namespace. The client will send a fragmented message to the server. * The prog attached to the server will shoot down any fragments. Thus, if * the server is able to correctly echo back the message to the client, we will * have verified that netfilter is reassembling packets for us. * * Topology: * ========= * NS0 | NS1 * | * client | server * ---------- | ---------- * | veth0 | --------- | veth1 | * ---------- peer ---------- * | * | with bpf */ #define NS0 "defrag_ns0" #define NS1 "defrag_ns1" #define VETH0 "veth0" #define VETH1 "veth1" #define VETH0_ADDR "172.16.1.100" #define VETH0_ADDR6 "fc00::100" /* The following constants must stay in sync with `generate_udp_fragments.py` */ #define VETH1_ADDR "172.16.1.200" #define VETH1_ADDR6 "fc00::200" #define CLIENT_PORT 48878 #define SERVER_PORT 48879 #define MAGIC_MESSAGE "THIS IS THE ORIGINAL MESSAGE, PLEASE REASSEMBLE ME" static int setup_topology(bool ipv6) { bool up; int i; SYS(fail, "ip netns add " NS0); SYS(fail, "ip netns add " NS1); SYS(fail, "ip link add " VETH0 " netns " NS0 " type veth peer name " VETH1 " netns " NS1); if (ipv6) { SYS(fail, "ip -6 -net " NS0 " addr add " VETH0_ADDR6 "/64 dev " VETH0 " nodad"); SYS(fail, "ip -6 -net " NS1 " addr add " VETH1_ADDR6 "/64 dev " VETH1 " nodad"); } else { SYS(fail, "ip -net " NS0 " addr add " VETH0_ADDR "/24 dev " VETH0); SYS(fail, "ip -net " NS1 " addr add " VETH1_ADDR "/24 dev " VETH1); } SYS(fail, "ip -net " NS0 " link set dev " VETH0 " up"); SYS(fail, "ip -net " NS1 " link set dev " VETH1 " up"); /* Wait for up to 5s for links to come up */ for (i = 0; i < 5; ++i) { if (ipv6) up = !SYS_NOFAIL("ip netns exec " NS0 " ping -6 -c 1 -W 1 " VETH1_ADDR6); else up = !SYS_NOFAIL("ip netns exec " NS0 " ping -c 1 -W 1 " VETH1_ADDR); if (up) break; } return 0; fail: return -1; } static void cleanup_topology(void) { SYS_NOFAIL("test -f /var/run/netns/" NS0 " && ip netns delete " NS0); SYS_NOFAIL("test -f /var/run/netns/" NS1 " && ip netns delete " NS1); } static int attach(struct ip_check_defrag *skel, bool ipv6) { LIBBPF_OPTS(bpf_netfilter_opts, opts, .pf = ipv6 ? NFPROTO_IPV6 : NFPROTO_IPV4, .priority = 42, .flags = BPF_F_NETFILTER_IP_DEFRAG); struct nstoken *nstoken; int err = -1; nstoken = open_netns(NS1); skel->links.defrag = bpf_program__attach_netfilter(skel->progs.defrag, &opts); if (!ASSERT_OK_PTR(skel->links.defrag, "program attach")) goto out; err = 0; out: close_netns(nstoken); return err; } static int send_frags(int client) { struct sockaddr_storage saddr; struct sockaddr *saddr_p; socklen_t saddr_len; int err; saddr_p = (struct sockaddr *)&saddr; err = make_sockaddr(AF_INET, VETH1_ADDR, SERVER_PORT, &saddr, &saddr_len); if (!ASSERT_OK(err, "make_sockaddr")) return -1; err = sendto(client, frag_0, sizeof(frag_0), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag_0")) return -1; err = sendto(client, frag_1, sizeof(frag_1), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag_1")) return -1; err = sendto(client, frag_2, sizeof(frag_2), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag_2")) return -1; return 0; } static int send_frags6(int client) { struct sockaddr_storage saddr; struct sockaddr *saddr_p; socklen_t saddr_len; int err; saddr_p = (struct sockaddr *)&saddr; /* Port needs to be set to 0 for raw ipv6 socket for some reason */ err = make_sockaddr(AF_INET6, VETH1_ADDR6, 0, &saddr, &saddr_len); if (!ASSERT_OK(err, "make_sockaddr")) return -1; err = sendto(client, frag6_0, sizeof(frag6_0), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag6_0")) return -1; err = sendto(client, frag6_1, sizeof(frag6_1), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag6_1")) return -1; err = sendto(client, frag6_2, sizeof(frag6_2), 0, saddr_p, saddr_len); if (!ASSERT_GE(err, 0, "sendto frag6_2")) return -1; return 0; } void test_bpf_ip_check_defrag_ok(bool ipv6) { struct network_helper_opts rx_opts = { .timeout_ms = 1000, .noconnect = true, }; struct network_helper_opts tx_ops = { .timeout_ms = 1000, .type = SOCK_RAW, .proto = IPPROTO_RAW, .noconnect = true, }; struct sockaddr_storage caddr; struct ip_check_defrag *skel; struct nstoken *nstoken; int client_tx_fd = -1; int client_rx_fd = -1; socklen_t caddr_len; int srv_fd = -1; char buf[1024]; int len, err; skel = ip_check_defrag__open_and_load(); if (!ASSERT_OK_PTR(skel, "skel_open")) return; if (!ASSERT_OK(setup_topology(ipv6), "setup_topology")) goto out; if (!ASSERT_OK(attach(skel, ipv6), "attach")) goto out; /* Start server in ns1 */ nstoken = open_netns(NS1); if (!ASSERT_OK_PTR(nstoken, "setns ns1")) goto out; srv_fd = start_server(ipv6 ? AF_INET6 : AF_INET, SOCK_DGRAM, NULL, SERVER_PORT, 0); close_netns(nstoken); if (!ASSERT_GE(srv_fd, 0, "start_server")) goto out; /* Open tx raw socket in ns0 */ nstoken = open_netns(NS0); if (!ASSERT_OK_PTR(nstoken, "setns ns0")) goto out; client_tx_fd = connect_to_fd_opts(srv_fd, &tx_ops); close_netns(nstoken); if (!ASSERT_GE(client_tx_fd, 0, "connect_to_fd_opts")) goto out; /* Open rx socket in ns0 */ nstoken = open_netns(NS0); if (!ASSERT_OK_PTR(nstoken, "setns ns0")) goto out; client_rx_fd = connect_to_fd_opts(srv_fd, &rx_opts); close_netns(nstoken); if (!ASSERT_GE(client_rx_fd, 0, "connect_to_fd_opts")) goto out; /* Bind rx socket to a premeditated port */ memset(&caddr, 0, sizeof(caddr)); nstoken = open_netns(NS0); if (!ASSERT_OK_PTR(nstoken, "setns ns0")) goto out; if (ipv6) { struct sockaddr_in6 *c = (struct sockaddr_in6 *)&caddr; c->sin6_family = AF_INET6; inet_pton(AF_INET6, VETH0_ADDR6, &c->sin6_addr); c->sin6_port = htons(CLIENT_PORT); err = bind(client_rx_fd, (struct sockaddr *)c, sizeof(*c)); } else { struct sockaddr_in *c = (struct sockaddr_in *)&caddr; c->sin_family = AF_INET; inet_pton(AF_INET, VETH0_ADDR, &c->sin_addr); c->sin_port = htons(CLIENT_PORT); err = bind(client_rx_fd, (struct sockaddr *)c, sizeof(*c)); } close_netns(nstoken); if (!ASSERT_OK(err, "bind")) goto out; /* Send message in fragments */ if (ipv6) { if (!ASSERT_OK(send_frags6(client_tx_fd), "send_frags6")) goto out; } else { if (!ASSERT_OK(send_frags(client_tx_fd), "send_frags")) goto out; } if (!ASSERT_EQ(skel->bss->shootdowns, 0, "shootdowns")) goto out; /* Receive reassembled msg on server and echo back to client */ caddr_len = sizeof(caddr); len = recvfrom(srv_fd, buf, sizeof(buf), 0, (struct sockaddr *)&caddr, &caddr_len); if (!ASSERT_GE(len, 0, "server recvfrom")) goto out; len = sendto(srv_fd, buf, len, 0, (struct sockaddr *)&caddr, caddr_len); if (!ASSERT_GE(len, 0, "server sendto")) goto out; /* Expect reassembed message to be echoed back */ len = recvfrom(client_rx_fd, buf, sizeof(buf), 0, NULL, NULL); if (!ASSERT_EQ(len, sizeof(MAGIC_MESSAGE) - 1, "client short read")) goto out; out: if (client_rx_fd != -1) close(client_rx_fd); if (client_tx_fd != -1) close(client_tx_fd); if (srv_fd != -1) close(srv_fd); cleanup_topology(); ip_check_defrag__destroy(skel); } void test_bpf_ip_check_defrag(void) { if (test__start_subtest("v4")) test_bpf_ip_check_defrag_ok(false); if (test__start_subtest("v6")) test_bpf_ip_check_defrag_ok(true); }