new file mode 100644
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Facebook
+// Copyright (c) 2019 Cloudflare
+// Copyright (c) 2020 Isovalent, Inc.
+/*
+ * Test that the socket assign program is able to redirect traffic towards a
+ * socket, regardless of whether the port or address destination of the traffic
+ * matches the port.
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "test_progs.h"
+
+#define BIND_PORT 1234
+#define CONNECT_PORT 4321
+#define TEST_DADDR (0xC0A80203)
+#define NS_SELF "/proc/self/ns/net"
+
+static const struct timeval timeo_sec = { .tv_sec = 3 };
+static const size_t timeo_optlen = sizeof(timeo_sec);
+static int stop, duration;
+
+static bool
+configure_stack(void)
+{
+ char tc_cmd[BUFSIZ];
+
+ /* Move to a new networking namespace */
+ if (CHECK_FAIL(unshare(CLONE_NEWNET)))
+ return false;
+
+ /* Configure necessary links, routes */
+ if (CHECK_FAIL(system("ip link set dev lo up")))
+ return false;
+ if (CHECK_FAIL(system("ip route add local default dev lo")))
+ return false;
+ if (CHECK_FAIL(system("ip -6 route add local default dev lo")))
+ return false;
+
+ /* Load qdisc, BPF program */
+ if (CHECK_FAIL(system("tc qdisc add dev lo clsact")))
+ return false;
+ sprintf(tc_cmd, "%s %s %s %s", "tc filter add dev lo ingress bpf",
+ "direct-action object-file ./test_sk_assign.o",
+ "section classifier/sk_assign_test",
+ (env.verbosity < VERBOSE_VERY) ? " 2>/dev/null" : "");
+ if (CHECK(system(tc_cmd), "BPF load failed;",
+ "run with -vv for more info\n"))
+ return false;
+
+ return true;
+}
+
+static int
+start_server(const struct sockaddr *addr, socklen_t len, int type)
+{
+ int fd;
+
+ fd = socket(addr->sa_family, type, 0);
+ if (CHECK_FAIL(fd == -1))
+ goto out;
+ if (CHECK_FAIL(setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeo_sec,
+ timeo_optlen)))
+ goto close_out;
+ if (CHECK_FAIL(bind(fd, addr, len) == -1))
+ goto close_out;
+ if (CHECK_FAIL(listen(fd, 128) == -1))
+ goto close_out;
+
+ goto out;
+close_out:
+ close(fd);
+ fd = -1;
+out:
+ return fd;
+}
+
+static int
+connect_to_server(const struct sockaddr *addr, socklen_t len, int type)
+{
+ int fd = -1;
+
+ fd = socket(addr->sa_family, type, 0);
+ if (CHECK_FAIL(fd == -1))
+ goto out;
+ if (CHECK_FAIL(setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeo_sec,
+ timeo_optlen)))
+ goto close_out;
+ if (CHECK_FAIL(connect(fd, addr, len)))
+ goto close_out;
+
+ goto out;
+close_out:
+ close(fd);
+ fd = -1;
+out:
+ return fd;
+}
+
+static in_port_t
+get_port(int fd)
+{
+ struct sockaddr_storage ss;
+ socklen_t slen = sizeof(ss);
+ in_port_t port = 0;
+
+ if (CHECK_FAIL(getsockname(fd, (struct sockaddr *)&ss, &slen)))
+ return port;
+
+ switch (ss.ss_family) {
+ case AF_INET:
+ port = ((struct sockaddr_in *)&ss)->sin_port;
+ break;
+ case AF_INET6:
+ port = ((struct sockaddr_in6 *)&ss)->sin6_port;
+ break;
+ default:
+ CHECK(1, "Invalid address family", "%d\n", ss.ss_family);
+ }
+ return port;
+}
+
+static int
+run_test(int server_fd, const struct sockaddr *addr, socklen_t len, int type)
+{
+ int client = -1, srv_client = -1;
+ char buf[] = "testing";
+ in_port_t port;
+ int ret = 1;
+
+ client = connect_to_server(addr, len, type);
+ if (client == -1) {
+ perror("Cannot connect to server");
+ goto out;
+ }
+
+ srv_client = accept(server_fd, NULL, NULL);
+ if (CHECK_FAIL(srv_client == -1)) {
+ perror("Can't accept connection");
+ goto out;
+ }
+ if (CHECK_FAIL(write(client, buf, sizeof(buf)) != sizeof(buf))) {
+ perror("Can't write on client");
+ goto out;
+ }
+ if (CHECK_FAIL(read(srv_client, &buf, sizeof(buf)) != sizeof(buf))) {
+ perror("Can't read on server");
+ goto out;
+ }
+
+ port = get_port(srv_client);
+ if (CHECK_FAIL(!port))
+ goto out;
+ if (CHECK(port != htons(CONNECT_PORT), "Expected", "port %u but got %u",
+ CONNECT_PORT, ntohs(port)))
+ goto out;
+
+ ret = 0;
+out:
+ close(client);
+ if (srv_client != server_fd)
+ close(srv_client);
+ if (ret)
+ WRITE_ONCE(stop, 1);
+ return ret;
+}
+
+static void
+prepare_addr(struct sockaddr *addr, int family, __u16 port, bool rewrite_addr)
+{
+ struct sockaddr_in *addr4;
+ struct sockaddr_in6 *addr6;
+
+ switch (family) {
+ case AF_INET:
+ addr4 = (struct sockaddr_in *)addr;
+ memset(addr4, 0, sizeof(*addr4));
+ addr4->sin_family = family;
+ addr4->sin_port = htons(port);
+ if (rewrite_addr)
+ addr4->sin_addr.s_addr = htonl(TEST_DADDR);
+ else
+ addr4->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ break;
+ case AF_INET6:
+ addr6 = (struct sockaddr_in6 *)addr;
+ memset(addr6, 0, sizeof(*addr6));
+ addr6->sin6_family = family;
+ addr6->sin6_port = htons(port);
+ addr6->sin6_addr = in6addr_loopback;
+ if (rewrite_addr)
+ addr6->sin6_addr.s6_addr32[3] = htonl(TEST_DADDR);
+ break;
+ default:
+ fprintf(stderr, "Invalid family %d", family);
+ }
+}
+
+struct test_sk_cfg {
+ const char *name;
+ int family;
+ struct sockaddr *addr;
+ socklen_t len;
+ int type;
+ bool rewrite_addr;
+};
+
+#define TEST(NAME, FAMILY, TYPE, REWRITE) \
+{ \
+ .name = NAME, \
+ .family = FAMILY, \
+ .addr = (FAMILY == AF_INET) ? (struct sockaddr *)&addr4 \
+ : (struct sockaddr *)&addr6, \
+ .len = (FAMILY == AF_INET) ? sizeof(addr4) : sizeof(addr6), \
+ .type = TYPE, \
+ .rewrite_addr = REWRITE, \
+}
+
+void test_sk_assign(void)
+{
+ struct sockaddr_in addr4;
+ struct sockaddr_in6 addr6;
+ struct test_sk_cfg tests[] = {
+ TEST("ipv4 tcp port redir", AF_INET, SOCK_STREAM, false),
+ TEST("ipv4 tcp addr redir", AF_INET, SOCK_STREAM, true),
+ TEST("ipv6 tcp port redir", AF_INET6, SOCK_STREAM, false),
+ TEST("ipv6 tcp addr redir", AF_INET6, SOCK_STREAM, true),
+ };
+ int server = -1;
+ int self_net;
+
+ self_net = open(NS_SELF, O_RDONLY);
+ if (CHECK_FAIL(self_net < 0)) {
+ perror("Unable to open "NS_SELF);
+ return;
+ }
+
+ if (!configure_stack()) {
+ perror("configure_stack");
+ goto cleanup;
+ }
+
+ for (int i = 0; i < ARRAY_SIZE(tests) && !READ_ONCE(stop); i++) {
+ struct test_sk_cfg *test = &tests[i];
+ const struct sockaddr *addr;
+
+ if (!test__start_subtest(test->name))
+ continue;
+ prepare_addr(test->addr, test->family, BIND_PORT, false);
+ addr = (const struct sockaddr *)test->addr;
+ server = start_server(addr, test->len, test->type);
+ if (server == -1)
+ goto cleanup;
+
+ /* connect to unbound ports */
+ prepare_addr(test->addr, test->family, CONNECT_PORT,
+ test->rewrite_addr);
+ if (run_test(server, addr, test->len, test->type))
+ goto close;
+
+ close(server);
+ server = -1;
+ }
+
+close:
+ close(server);
+cleanup:
+ if (CHECK_FAIL(setns(self_net, CLONE_NEWNET)))
+ perror("Failed to setns("NS_SELF")");
+ close(self_net);
+}
new file mode 100644
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Cloudflare Ltd.
+// Copyright (c) 2020 Isovalent, Inc.
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/pkt_cls.h>
+#include <linux/tcp.h>
+#include <sys/socket.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+int _version SEC("version") = 1;
+char _license[] SEC("license") = "GPL";
+
+/* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */
+static inline struct bpf_sock_tuple *
+get_tuple(struct __sk_buff *skb, bool *ipv4)
+{
+ void *data_end = (void *)(long)skb->data_end;
+ void *data = (void *)(long)skb->data;
+ struct bpf_sock_tuple *result;
+ struct ethhdr *eth;
+ __u64 tuple_len;
+ __u8 proto = 0;
+ __u64 ihl_len;
+
+ eth = (struct ethhdr *)(data);
+ if (eth + 1 > data_end)
+ return NULL;
+
+ if (eth->h_proto == bpf_htons(ETH_P_IP)) {
+ struct iphdr *iph = (struct iphdr *)(data + sizeof(*eth));
+
+ if (iph + 1 > data_end)
+ return NULL;
+ if (iph->ihl != 5)
+ /* Options are not supported */
+ return NULL;
+ ihl_len = iph->ihl * 4;
+ proto = iph->protocol;
+ *ipv4 = true;
+ result = (struct bpf_sock_tuple *)&iph->saddr;
+ } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(data + sizeof(*eth));
+
+ if (ip6h + 1 > data_end)
+ return NULL;
+ ihl_len = sizeof(*ip6h);
+ proto = ip6h->nexthdr;
+ *ipv4 = false;
+ result = (struct bpf_sock_tuple *)&ip6h->saddr;
+ } else {
+ return (struct bpf_sock_tuple *)data;
+ }
+
+ if (result + 1 > data_end || proto != IPPROTO_TCP)
+ return NULL;
+
+ return result;
+}
+
+static inline int
+handle_tcp(struct __sk_buff *skb, struct bpf_sock_tuple *tuple, bool ipv4)
+{
+ struct bpf_sock_tuple ln = {0};
+ struct bpf_sock *sk;
+ size_t tuple_len;
+ int ret;
+
+ tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6);
+ if ((void *)tuple + tuple_len > skb->data_end)
+ return TC_ACT_SHOT;
+
+ sk = bpf_skc_lookup_tcp(skb, tuple, tuple_len, BPF_F_CURRENT_NETNS, 0);
+ if (sk) {
+ if (sk->state != BPF_TCP_LISTEN)
+ goto assign;
+ bpf_sk_release(sk);
+ }
+
+ if (ipv4) {
+ if (tuple->ipv4.dport != bpf_htons(4321))
+ return TC_ACT_OK;
+
+ ln.ipv4.daddr = bpf_htonl(0x7f000001);
+ ln.ipv4.dport = bpf_htons(1234);
+
+ sk = bpf_skc_lookup_tcp(skb, &ln, sizeof(ln.ipv4),
+ BPF_F_CURRENT_NETNS, 0);
+ } else {
+ if (tuple->ipv6.dport != bpf_htons(4321))
+ return TC_ACT_OK;
+
+ /* Upper parts of daddr are already zero. */
+ ln.ipv6.daddr[3] = bpf_htonl(0x1);
+ ln.ipv6.dport = bpf_htons(1234);
+
+ sk = bpf_skc_lookup_tcp(skb, &ln, sizeof(ln.ipv6),
+ BPF_F_CURRENT_NETNS, 0);
+ }
+
+ /* workaround: We can't do a single socket lookup here, because then
+ * the compiler will likely spill tuple_len to the stack. This makes it
+ * lose all bounds information in the verifier, which then rejects the
+ * call as unsafe.
+ */
+ if (!sk)
+ return TC_ACT_SHOT;
+
+ if (sk->state != BPF_TCP_LISTEN) {
+ bpf_sk_release(sk);
+ return TC_ACT_SHOT;
+ }
+
+assign:
+ ret = bpf_sk_assign(skb, sk, 0);
+ bpf_sk_release(sk);
+ return ret;
+}
+
+SEC("classifier/sk_assign_test")
+int bpf_sk_assign_test(struct __sk_buff *skb)
+{
+ struct bpf_sock_tuple *tuple, ln = {0};
+ bool ipv4 = false;
+ int tuple_len;
+ int ret = 0;
+
+ tuple = get_tuple(skb, &ipv4);
+ if (!tuple)
+ return TC_ACT_SHOT;
+
+ ret = handle_tcp(skb, tuple, ipv4);
+
+ return ret == 0 ? TC_ACT_OK : TC_ACT_SHOT;
+}