This patch reuses the framework already in place for sk_lookup, allowing it now to send a reply from the server fd directly, instead of having to create a socket bound to the original destination address and reply from there. It does this by passing the source address and port from where to reply from in a IP_ORIGDSTADDR ancillary message passed in sendmsg.
Signed-off-by: Tiago Lam tiagolam@cloudflare.com --- tools/testing/selftests/bpf/prog_tests/sk_lookup.c | 67 +++++++++++++++------- 1 file changed, 45 insertions(+), 22 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c index ae87c00867ba..df780624c16c 100644 --- a/tools/testing/selftests/bpf/prog_tests/sk_lookup.c +++ b/tools/testing/selftests/bpf/prog_tests/sk_lookup.c @@ -75,6 +75,7 @@ struct test { struct inet_addr listen_at; enum server accept_on; bool reuseport_has_conns; /* Add a connected socket to reuseport group */ + bool dont_bind_reply; /* Don't bind, send direct from server fd. */ };
struct cb_opts { @@ -363,7 +364,7 @@ static void v4_to_v6(struct sockaddr_storage *ss) memset(&v6->sin6_addr.s6_addr[0], 0, 10); }
-static int udp_recv_send(int server_fd) +static int udp_recv_send(int server_fd, bool dont_bind_reply) { char cmsg_buf[CMSG_SPACE(sizeof(struct sockaddr_storage))]; struct sockaddr_storage _src_addr = { 0 }; @@ -373,7 +374,7 @@ static int udp_recv_send(int server_fd) struct iovec iov = { 0 }; struct cmsghdr *cm; char buf[1]; - int ret, fd; + int fd; ssize_t n;
iov.iov_base = buf; @@ -415,26 +416,37 @@ static int udp_recv_send(int server_fd) v4_to_v6(dst_addr); }
- /* Reply from original destination address. */ - fd = start_server_addr(SOCK_DGRAM, dst_addr, sizeof(*dst_addr), NULL); - if (!ASSERT_OK_FD(fd, "start_server_addr")) { - log_err("failed to create tx socket"); - return -1; - } + if (dont_bind_reply) { + /* Reply directly from server fd, specifying the source address + * and/or port in struct msghdr. + */ + n = sendmsg(server_fd, &msg, 0); + if (CHECK(n <= 0, "sendmsg", "failed\n")) { + log_err("failed to send echo reply"); + return -1; + } + } else { + /* Reply from original destination address. */ + fd = start_server_addr(SOCK_DGRAM, dst_addr, sizeof(*dst_addr), + NULL); + if (!ASSERT_OK_FD(fd, "start_server_addr")) { + log_err("failed to create tx socket"); + return -1; + }
- msg.msg_control = NULL; - msg.msg_controllen = 0; - n = sendmsg(fd, &msg, 0); - if (CHECK(n <= 0, "sendmsg", "failed\n")) { - log_err("failed to send echo reply"); - ret = -1; - goto out; + msg.msg_control = NULL; + msg.msg_controllen = 0; + n = sendmsg(fd, &msg, 0); + if (CHECK(n <= 0, "sendmsg", "failed\n")) { + log_err("failed to send echo reply"); + close(fd); + return -1; + } + + close(fd); }
- ret = 0; -out: - close(fd); - return ret; + return 0; }
static int tcp_echo_test(int client_fd, int server_fd) @@ -454,14 +466,14 @@ static int tcp_echo_test(int client_fd, int server_fd) return 0; }
-static int udp_echo_test(int client_fd, int server_fd) +static int udp_echo_test(int client_fd, int server_fd, bool dont_bind_reply) { int err;
err = send_byte(client_fd); if (err) return -1; - err = udp_recv_send(server_fd); + err = udp_recv_send(server_fd, dont_bind_reply); if (err) return -1; err = recv_byte(client_fd); @@ -653,7 +665,8 @@ static void run_lookup_prog(const struct test *t) if (t->sotype == SOCK_STREAM) tcp_echo_test(client_fd, server_fds[t->accept_on]); else - udp_echo_test(client_fd, server_fds[t->accept_on]); + udp_echo_test(client_fd, server_fds[t->accept_on], + t->dont_bind_reply);
close(client_fd); close: @@ -775,6 +788,16 @@ static void test_redirect_lookup(struct test_sk_lookup *skel) .listen_at = { INT_IP4, INT_PORT }, .accept_on = SERVER_B, }, + { + .desc = "UDP IPv4 redir different ports", + .lookup_prog = skel->progs.select_sock_a_no_reuseport, + .sock_map = skel->maps.redir_map, + .sotype = SOCK_DGRAM, + .connect_to = { EXT_IP4, EXT_PORT }, + .listen_at = { INT_IP4, INT_PORT }, + .accept_on = SERVER_A, + .dont_bind_reply = true, + }, { .desc = "UDP IPv4 redir and reuseport with conns", .lookup_prog = skel->progs.select_sock_a,