bpf: selftest: Test batching and bpf_(get|set)sockopt in bpf tcp iter
authorMartin KaFai Lau <kafai@fb.com>
Thu, 1 Jul 2021 20:06:25 +0000 (13:06 -0700)
committerAndrii Nakryiko <andrii@kernel.org>
Fri, 23 Jul 2021 23:45:17 +0000 (16:45 -0700)
This patch adds tests for the batching and bpf_(get|set)sockopt in
bpf tcp iter.

It first creates:
a) 1 non SO_REUSEPORT listener in lhash2.
b) 256 passive and active fds connected to the listener in (a).
c) 256 SO_REUSEPORT listeners in one of the lhash2 bucket.

The test sets all listeners and connections to bpf_cubic before
running the bpf iter.

The bpf iter then calls setsockopt(TCP_CONGESTION) to switch
each listener and connection from bpf_cubic to bpf_dctcp.

The bpf iter has a random_retry mode such that it can return EAGAIN
to the usespace in the middle of a batch.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200625.1036874-1-kafai@fb.com
tools/testing/selftests/bpf/network_helpers.c
tools/testing/selftests/bpf/network_helpers.h
tools/testing/selftests/bpf/prog_tests/bpf_iter_setsockopt.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/bpf_iter_setsockopt.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/bpf_tracing_net.h

index 2060bc1..26468a8 100644 (file)
@@ -66,17 +66,13 @@ int settimeo(int fd, int timeout_ms)
 
 #define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })
 
-int start_server(int family, int type, const char *addr_str, __u16 port,
-                int timeout_ms)
+static int __start_server(int type, const struct sockaddr *addr,
+                         socklen_t addrlen, int timeout_ms, bool reuseport)
 {
-       struct sockaddr_storage addr = {};
-       socklen_t len;
+       int on = 1;
        int fd;
 
-       if (make_sockaddr(family, addr_str, port, &addr, &len))
-               return -1;
-
-       fd = socket(family, type, 0);
+       fd = socket(addr->sa_family, type, 0);
        if (fd < 0) {
                log_err("Failed to create server socket");
                return -1;
@@ -85,7 +81,13 @@ int start_server(int family, int type, const char *addr_str, __u16 port,
        if (settimeo(fd, timeout_ms))
                goto error_close;
 
-       if (bind(fd, (const struct sockaddr *)&addr, len) < 0) {
+       if (reuseport &&
+           setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on))) {
+               log_err("Failed to set SO_REUSEPORT");
+               return -1;
+       }
+
+       if (bind(fd, addr, addrlen) < 0) {
                log_err("Failed to bind socket");
                goto error_close;
        }
@@ -104,6 +106,69 @@ error_close:
        return -1;
 }
 
+int start_server(int family, int type, const char *addr_str, __u16 port,
+                int timeout_ms)
+{
+       struct sockaddr_storage addr;
+       socklen_t addrlen;
+
+       if (make_sockaddr(family, addr_str, port, &addr, &addrlen))
+               return -1;
+
+       return __start_server(type, (struct sockaddr *)&addr,
+                             addrlen, timeout_ms, false);
+}
+
+int *start_reuseport_server(int family, int type, const char *addr_str,
+                           __u16 port, int timeout_ms, unsigned int nr_listens)
+{
+       struct sockaddr_storage addr;
+       unsigned int nr_fds = 0;
+       socklen_t addrlen;
+       int *fds;
+
+       if (!nr_listens)
+               return NULL;
+
+       if (make_sockaddr(family, addr_str, port, &addr, &addrlen))
+               return NULL;
+
+       fds = malloc(sizeof(*fds) * nr_listens);
+       if (!fds)
+               return NULL;
+
+       fds[0] = __start_server(type, (struct sockaddr *)&addr, addrlen,
+                               timeout_ms, true);
+       if (fds[0] == -1)
+               goto close_fds;
+       nr_fds = 1;
+
+       if (getsockname(fds[0], (struct sockaddr *)&addr, &addrlen))
+               goto close_fds;
+
+       for (; nr_fds < nr_listens; nr_fds++) {
+               fds[nr_fds] = __start_server(type, (struct sockaddr *)&addr,
+                                            addrlen, timeout_ms, true);
+               if (fds[nr_fds] == -1)
+                       goto close_fds;
+       }
+
+       return fds;
+
+close_fds:
+       free_fds(fds, nr_fds);
+       return NULL;
+}
+
+void free_fds(int *fds, unsigned int nr_close_fds)
+{
+       if (fds) {
+               while (nr_close_fds)
+                       close(fds[--nr_close_fds]);
+               free(fds);
+       }
+}
+
 int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
                     int timeout_ms)
 {
@@ -217,6 +282,7 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
        if (family == AF_INET) {
                struct sockaddr_in *sin = (void *)addr;
 
+               memset(addr, 0, sizeof(*sin));
                sin->sin_family = AF_INET;
                sin->sin_port = htons(port);
                if (addr_str &&
@@ -230,6 +296,7 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
        } else if (family == AF_INET6) {
                struct sockaddr_in6 *sin6 = (void *)addr;
 
+               memset(addr, 0, sizeof(*sin6));
                sin6->sin6_family = AF_INET6;
                sin6->sin6_port = htons(port);
                if (addr_str &&
index 5e0d51c..d60bc28 100644 (file)
@@ -36,6 +36,10 @@ extern struct ipv6_packet pkt_v6;
 int settimeo(int fd, int timeout_ms);
 int start_server(int family, int type, const char *addr, __u16 port,
                 int timeout_ms);
+int *start_reuseport_server(int family, int type, const char *addr_str,
+                           __u16 port, int timeout_ms,
+                           unsigned int nr_listens);
+void free_fds(int *fds, unsigned int nr_close_fds);
 int connect_to_fd(int server_fd, int timeout_ms);
 int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms);
 int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter_setsockopt.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter_setsockopt.c
new file mode 100644 (file)
index 0000000..85babb0
--- /dev/null
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#define _GNU_SOURCE
+#include <sched.h>
+#include <test_progs.h>
+#include "network_helpers.h"
+#include "bpf_dctcp.skel.h"
+#include "bpf_cubic.skel.h"
+#include "bpf_iter_setsockopt.skel.h"
+
+static int create_netns(void)
+{
+       if (!ASSERT_OK(unshare(CLONE_NEWNET), "create netns"))
+               return -1;
+
+       if (!ASSERT_OK(system("ip link set dev lo up"), "bring up lo"))
+               return -1;
+
+       return 0;
+}
+
+static unsigned int set_bpf_cubic(int *fds, unsigned int nr_fds)
+{
+       unsigned int i;
+
+       for (i = 0; i < nr_fds; i++) {
+               if (setsockopt(fds[i], SOL_TCP, TCP_CONGESTION, "bpf_cubic",
+                              sizeof("bpf_cubic")))
+                       return i;
+       }
+
+       return nr_fds;
+}
+
+static unsigned int check_bpf_dctcp(int *fds, unsigned int nr_fds)
+{
+       char tcp_cc[16];
+       socklen_t optlen = sizeof(tcp_cc);
+       unsigned int i;
+
+       for (i = 0; i < nr_fds; i++) {
+               if (getsockopt(fds[i], SOL_TCP, TCP_CONGESTION,
+                              tcp_cc, &optlen) ||
+                   strcmp(tcp_cc, "bpf_dctcp"))
+                       return i;
+       }
+
+       return nr_fds;
+}
+
+static int *make_established(int listen_fd, unsigned int nr_est,
+                            int **paccepted_fds)
+{
+       int *est_fds, *accepted_fds;
+       unsigned int i;
+
+       est_fds = malloc(sizeof(*est_fds) * nr_est);
+       if (!est_fds)
+               return NULL;
+
+       accepted_fds = malloc(sizeof(*accepted_fds) * nr_est);
+       if (!accepted_fds) {
+               free(est_fds);
+               return NULL;
+       }
+
+       for (i = 0; i < nr_est; i++) {
+               est_fds[i] = connect_to_fd(listen_fd, 0);
+               if (est_fds[i] == -1)
+                       break;
+               if (set_bpf_cubic(&est_fds[i], 1) != 1) {
+                       close(est_fds[i]);
+                       break;
+               }
+
+               accepted_fds[i] = accept(listen_fd, NULL, 0);
+               if (accepted_fds[i] == -1) {
+                       close(est_fds[i]);
+                       break;
+               }
+       }
+
+       if (!ASSERT_EQ(i, nr_est, "create established fds")) {
+               free_fds(accepted_fds, i);
+               free_fds(est_fds, i);
+               return NULL;
+       }
+
+       *paccepted_fds = accepted_fds;
+       return est_fds;
+}
+
+static unsigned short get_local_port(int fd)
+{
+       struct sockaddr_in6 addr;
+       socklen_t addrlen = sizeof(addr);
+
+       if (!getsockname(fd, &addr, &addrlen))
+               return ntohs(addr.sin6_port);
+
+       return 0;
+}
+
+static void do_bpf_iter_setsockopt(struct bpf_iter_setsockopt *iter_skel,
+                                  bool random_retry)
+{
+       int *reuse_listen_fds = NULL, *accepted_fds = NULL, *est_fds = NULL;
+       unsigned int nr_reuse_listens = 256, nr_est = 256;
+       int err, iter_fd = -1, listen_fd = -1;
+       char buf;
+
+       /* Prepare non-reuseport listen_fd */
+       listen_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
+       if (!ASSERT_GE(listen_fd, 0, "start_server"))
+               return;
+       if (!ASSERT_EQ(set_bpf_cubic(&listen_fd, 1), 1,
+                      "set listen_fd to cubic"))
+               goto done;
+       iter_skel->bss->listen_hport = get_local_port(listen_fd);
+       if (!ASSERT_NEQ(iter_skel->bss->listen_hport, 0,
+                       "get_local_port(listen_fd)"))
+               goto done;
+
+       /* Connect to non-reuseport listen_fd */
+       est_fds = make_established(listen_fd, nr_est, &accepted_fds);
+       if (!ASSERT_OK_PTR(est_fds, "create established"))
+               goto done;
+
+       /* Prepare reuseport listen fds */
+       reuse_listen_fds = start_reuseport_server(AF_INET6, SOCK_STREAM,
+                                                 "::1", 0, 0,
+                                                 nr_reuse_listens);
+       if (!ASSERT_OK_PTR(reuse_listen_fds, "start_reuseport_server"))
+               goto done;
+       if (!ASSERT_EQ(set_bpf_cubic(reuse_listen_fds, nr_reuse_listens),
+                      nr_reuse_listens, "set reuse_listen_fds to cubic"))
+               goto done;
+       iter_skel->bss->reuse_listen_hport = get_local_port(reuse_listen_fds[0]);
+       if (!ASSERT_NEQ(iter_skel->bss->reuse_listen_hport, 0,
+                       "get_local_port(reuse_listen_fds[0])"))
+               goto done;
+
+       /* Run bpf tcp iter to switch from bpf_cubic to bpf_dctcp */
+       iter_skel->bss->random_retry = random_retry;
+       iter_fd = bpf_iter_create(bpf_link__fd(iter_skel->links.change_tcp_cc));
+       if (!ASSERT_GE(iter_fd, 0, "create iter_fd"))
+               goto done;
+
+       while ((err = read(iter_fd, &buf, sizeof(buf))) == -1 &&
+              errno == EAGAIN)
+               ;
+       if (!ASSERT_OK(err, "read iter error"))
+               goto done;
+
+       /* Check reuseport listen fds for dctcp */
+       ASSERT_EQ(check_bpf_dctcp(reuse_listen_fds, nr_reuse_listens),
+                 nr_reuse_listens,
+                 "check reuse_listen_fds dctcp");
+
+       /* Check non reuseport listen fd for dctcp */
+       ASSERT_EQ(check_bpf_dctcp(&listen_fd, 1), 1,
+                 "check listen_fd dctcp");
+
+       /* Check established fds for dctcp */
+       ASSERT_EQ(check_bpf_dctcp(est_fds, nr_est), nr_est,
+                 "check est_fds dctcp");
+
+       /* Check accepted fds for dctcp */
+       ASSERT_EQ(check_bpf_dctcp(accepted_fds, nr_est), nr_est,
+                 "check accepted_fds dctcp");
+
+done:
+       if (iter_fd != -1)
+               close(iter_fd);
+       if (listen_fd != -1)
+               close(listen_fd);
+       free_fds(reuse_listen_fds, nr_reuse_listens);
+       free_fds(accepted_fds, nr_est);
+       free_fds(est_fds, nr_est);
+}
+
+void test_bpf_iter_setsockopt(void)
+{
+       struct bpf_iter_setsockopt *iter_skel = NULL;
+       struct bpf_cubic *cubic_skel = NULL;
+       struct bpf_dctcp *dctcp_skel = NULL;
+       struct bpf_link *cubic_link = NULL;
+       struct bpf_link *dctcp_link = NULL;
+
+       if (create_netns())
+               return;
+
+       /* Load iter_skel */
+       iter_skel = bpf_iter_setsockopt__open_and_load();
+       if (!ASSERT_OK_PTR(iter_skel, "iter_skel"))
+               return;
+       iter_skel->links.change_tcp_cc = bpf_program__attach_iter(iter_skel->progs.change_tcp_cc, NULL);
+       if (!ASSERT_OK_PTR(iter_skel->links.change_tcp_cc, "attach iter"))
+               goto done;
+
+       /* Load bpf_cubic */
+       cubic_skel = bpf_cubic__open_and_load();
+       if (!ASSERT_OK_PTR(cubic_skel, "cubic_skel"))
+               goto done;
+       cubic_link = bpf_map__attach_struct_ops(cubic_skel->maps.cubic);
+       if (!ASSERT_OK_PTR(cubic_link, "cubic_link"))
+               goto done;
+
+       /* Load bpf_dctcp */
+       dctcp_skel = bpf_dctcp__open_and_load();
+       if (!ASSERT_OK_PTR(dctcp_skel, "dctcp_skel"))
+               goto done;
+       dctcp_link = bpf_map__attach_struct_ops(dctcp_skel->maps.dctcp);
+       if (!ASSERT_OK_PTR(dctcp_link, "dctcp_link"))
+               goto done;
+
+       do_bpf_iter_setsockopt(iter_skel, true);
+       do_bpf_iter_setsockopt(iter_skel, false);
+
+done:
+       bpf_link__destroy(cubic_link);
+       bpf_link__destroy(dctcp_link);
+       bpf_cubic__destroy(cubic_skel);
+       bpf_dctcp__destroy(dctcp_skel);
+       bpf_iter_setsockopt__destroy(iter_skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_setsockopt.c b/tools/testing/selftests/bpf/progs/bpf_iter_setsockopt.c
new file mode 100644 (file)
index 0000000..b77adfd
--- /dev/null
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include "bpf_iter.h"
+#include "bpf_tracing_net.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+#define bpf_tcp_sk(skc)        ({                              \
+       struct sock_common *_skc = skc;                 \
+       sk = NULL;                                      \
+       tp = NULL;                                      \
+       if (_skc) {                                     \
+               tp = bpf_skc_to_tcp_sock(_skc);         \
+               sk = (struct sock *)tp;                 \
+       }                                               \
+       tp;                                             \
+})
+
+unsigned short reuse_listen_hport = 0;
+unsigned short listen_hport = 0;
+char cubic_cc[TCP_CA_NAME_MAX] = "bpf_cubic";
+char dctcp_cc[TCP_CA_NAME_MAX] = "bpf_dctcp";
+bool random_retry = false;
+
+static bool tcp_cc_eq(const char *a, const char *b)
+{
+       int i;
+
+       for (i = 0; i < TCP_CA_NAME_MAX; i++) {
+               if (a[i] != b[i])
+                       return false;
+               if (!a[i])
+                       break;
+       }
+
+       return true;
+}
+
+SEC("iter/tcp")
+int change_tcp_cc(struct bpf_iter__tcp *ctx)
+{
+       char cur_cc[TCP_CA_NAME_MAX];
+       struct tcp_sock *tp;
+       struct sock *sk;
+       int ret;
+
+       if (!bpf_tcp_sk(ctx->sk_common))
+               return 0;
+
+       if (sk->sk_family != AF_INET6 ||
+           (sk->sk_state != TCP_LISTEN &&
+            sk->sk_state != TCP_ESTABLISHED) ||
+           (sk->sk_num != reuse_listen_hport &&
+            sk->sk_num != listen_hport &&
+            bpf_ntohs(sk->sk_dport) != listen_hport))
+               return 0;
+
+       if (bpf_getsockopt(tp, SOL_TCP, TCP_CONGESTION,
+                          cur_cc, sizeof(cur_cc)))
+               return 0;
+
+       if (!tcp_cc_eq(cur_cc, cubic_cc))
+               return 0;
+
+       if (random_retry && bpf_get_prandom_u32() % 4 == 1)
+               return 1;
+
+       bpf_setsockopt(tp, SOL_TCP, TCP_CONGESTION, dctcp_cc, sizeof(dctcp_cc));
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";
index 0137891..3af0998 100644 (file)
@@ -5,6 +5,10 @@
 #define AF_INET                        2
 #define AF_INET6               10
 
+#define SOL_TCP                        6
+#define TCP_CONGESTION         13
+#define TCP_CA_NAME_MAX                16
+
 #define ICSK_TIME_RETRANS      1
 #define ICSK_TIME_PROBE0       3
 #define ICSK_TIME_LOSS_PROBE   5
@@ -32,6 +36,8 @@
 #define ir_v6_rmt_addr         req.__req_common.skc_v6_daddr
 #define ir_v6_loc_addr         req.__req_common.skc_v6_rcv_saddr
 
+#define sk_num                 __sk_common.skc_num
+#define sk_dport               __sk_common.skc_dport
 #define sk_family              __sk_common.skc_family
 #define sk_rmem_alloc          sk_backlog.rmem_alloc
 #define sk_refcnt              __sk_common.skc_refcnt