selftests/bpf: add a test case for sock_ops perf-event notification
This patch provides a tcp_bpf based eBPF sample. The test - ncat(1) as the TCP client program to connect() to a port with the intention of triggerring SYN retransmissions: we first install an iptables DROP rule to make sure ncat SYNs are resent (instead of aborting instantly after a TCP RST) - has a bpf kernel module that sends a perf-event notification for each TCP retransmit, and also tracks the number of such notifications sent in the global_map The test passes when the number of event notifications intercepted in user-space matches the value in the global_map. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Sowmini Varadhan
Daniel Borkmann
parent
a5a3a828cd
commit
435f90a338
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@ -24,12 +24,13 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
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test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
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test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \
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test_socket_cookie test_cgroup_storage test_select_reuseport test_section_names \
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test_netcnt
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test_netcnt test_tcpnotify_user
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TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
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test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
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sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \
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test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \
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test_tcpnotify_kern.o \
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sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
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sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
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test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
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@ -74,6 +75,7 @@ $(OUTPUT)/test_sock_addr: cgroup_helpers.c
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$(OUTPUT)/test_socket_cookie: cgroup_helpers.c
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$(OUTPUT)/test_sockmap: cgroup_helpers.c
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$(OUTPUT)/test_tcpbpf_user: cgroup_helpers.c
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$(OUTPUT)/test_tcpnotify_user: cgroup_helpers.c trace_helpers.c
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$(OUTPUT)/test_progs: trace_helpers.c
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$(OUTPUT)/get_cgroup_id_user: cgroup_helpers.c
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$(OUTPUT)/test_cgroup_storage: cgroup_helpers.c
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@ -0,0 +1,19 @@
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// SPDX-License-Identifier: GPL-2.0
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#ifndef _TEST_TCPBPF_H
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#define _TEST_TCPBPF_H
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struct tcpnotify_globals {
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__u32 total_retrans;
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__u32 ncalls;
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};
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struct tcp_notifier {
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__u8 type;
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__u8 subtype;
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__u8 source;
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__u8 hash;
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};
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#define TESTPORT 12877
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#endif
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@ -0,0 +1,95 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <stddef.h>
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#include <string.h>
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#include <linux/bpf.h>
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#include <linux/if_ether.h>
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#include <linux/if_packet.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/tcp.h>
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#include <netinet/in.h>
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#include "bpf_helpers.h"
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#include "bpf_endian.h"
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#include "test_tcpnotify.h"
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struct bpf_map_def SEC("maps") global_map = {
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.type = BPF_MAP_TYPE_ARRAY,
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.key_size = sizeof(__u32),
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.value_size = sizeof(struct tcpnotify_globals),
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.max_entries = 4,
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};
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struct bpf_map_def SEC("maps") perf_event_map = {
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.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
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.key_size = sizeof(int),
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.value_size = sizeof(__u32),
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.max_entries = 2,
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};
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int _version SEC("version") = 1;
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SEC("sockops")
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int bpf_testcb(struct bpf_sock_ops *skops)
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{
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int rv = -1;
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int op;
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op = (int) skops->op;
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if (bpf_ntohl(skops->remote_port) != TESTPORT) {
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skops->reply = -1;
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return 0;
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}
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switch (op) {
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case BPF_SOCK_OPS_TIMEOUT_INIT:
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case BPF_SOCK_OPS_RWND_INIT:
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case BPF_SOCK_OPS_NEEDS_ECN:
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case BPF_SOCK_OPS_BASE_RTT:
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case BPF_SOCK_OPS_RTO_CB:
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rv = 1;
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break;
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case BPF_SOCK_OPS_TCP_CONNECT_CB:
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case BPF_SOCK_OPS_TCP_LISTEN_CB:
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case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
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case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
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bpf_sock_ops_cb_flags_set(skops, (BPF_SOCK_OPS_RETRANS_CB_FLAG|
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BPF_SOCK_OPS_RTO_CB_FLAG));
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rv = 1;
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break;
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case BPF_SOCK_OPS_RETRANS_CB: {
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__u32 key = 0;
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struct tcpnotify_globals g, *gp;
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struct tcp_notifier msg = {
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.type = 0xde,
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.subtype = 0xad,
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.source = 0xbe,
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.hash = 0xef,
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};
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rv = 1;
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/* Update results */
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gp = bpf_map_lookup_elem(&global_map, &key);
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if (!gp)
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break;
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g = *gp;
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g.total_retrans = skops->total_retrans;
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g.ncalls++;
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bpf_map_update_elem(&global_map, &key, &g,
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BPF_ANY);
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bpf_perf_event_output(skops, &perf_event_map,
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BPF_F_CURRENT_CPU,
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&msg, sizeof(msg));
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}
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break;
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default:
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rv = -1;
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}
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skops->reply = rv;
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return 1;
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}
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char _license[] SEC("license") = "GPL";
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@ -0,0 +1,186 @@
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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <pthread.h>
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#include <inttypes.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <asm/types.h>
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#include <sys/syscall.h>
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#include <errno.h>
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#include <string.h>
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#include <linux/bpf.h>
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#include <sys/socket.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include <sys/ioctl.h>
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#include <linux/rtnetlink.h>
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#include <signal.h>
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#include <linux/perf_event.h>
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#include "bpf_rlimit.h"
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#include "bpf_util.h"
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#include "cgroup_helpers.h"
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#include "test_tcpnotify.h"
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#include "trace_helpers.h"
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#define SOCKET_BUFFER_SIZE (getpagesize() < 8192L ? getpagesize() : 8192L)
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pthread_t tid;
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int rx_callbacks;
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static int dummyfn(void *data, int size)
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{
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struct tcp_notifier *t = data;
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if (t->type != 0xde || t->subtype != 0xad ||
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t->source != 0xbe || t->hash != 0xef)
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return 1;
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rx_callbacks++;
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return 0;
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}
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void tcp_notifier_poller(int fd)
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{
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while (1)
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perf_event_poller(fd, dummyfn);
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}
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static void *poller_thread(void *arg)
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{
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int fd = *(int *)arg;
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tcp_notifier_poller(fd);
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return arg;
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}
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int verify_result(const struct tcpnotify_globals *result)
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{
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return (result->ncalls > 0 && result->ncalls == rx_callbacks ? 0 : 1);
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}
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static int bpf_find_map(const char *test, struct bpf_object *obj,
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const char *name)
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{
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struct bpf_map *map;
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map = bpf_object__find_map_by_name(obj, name);
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if (!map) {
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printf("%s:FAIL:map '%s' not found\n", test, name);
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return -1;
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}
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return bpf_map__fd(map);
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}
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static int setup_bpf_perf_event(int mapfd)
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{
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struct perf_event_attr attr = {
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.sample_type = PERF_SAMPLE_RAW,
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_BPF_OUTPUT,
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};
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int key = 0;
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int pmu_fd;
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pmu_fd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, 0);
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if (pmu_fd < 0)
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return pmu_fd;
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bpf_map_update_elem(mapfd, &key, &pmu_fd, BPF_ANY);
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ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
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return pmu_fd;
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}
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int main(int argc, char **argv)
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{
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const char *file = "test_tcpnotify_kern.o";
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int prog_fd, map_fd, perf_event_fd;
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struct tcpnotify_globals g = {0};
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const char *cg_path = "/foo";
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int error = EXIT_FAILURE;
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struct bpf_object *obj;
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int cg_fd = -1;
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__u32 key = 0;
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int rv;
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char test_script[80];
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int pmu_fd;
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cpu_set_t cpuset;
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CPU_ZERO(&cpuset);
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CPU_SET(0, &cpuset);
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pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
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if (setup_cgroup_environment())
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goto err;
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cg_fd = create_and_get_cgroup(cg_path);
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if (!cg_fd)
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goto err;
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if (join_cgroup(cg_path))
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goto err;
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if (bpf_prog_load(file, BPF_PROG_TYPE_SOCK_OPS, &obj, &prog_fd)) {
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printf("FAILED: load_bpf_file failed for: %s\n", file);
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goto err;
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}
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rv = bpf_prog_attach(prog_fd, cg_fd, BPF_CGROUP_SOCK_OPS, 0);
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if (rv) {
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printf("FAILED: bpf_prog_attach: %d (%s)\n",
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error, strerror(errno));
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goto err;
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}
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perf_event_fd = bpf_find_map(__func__, obj, "perf_event_map");
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if (perf_event_fd < 0)
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goto err;
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map_fd = bpf_find_map(__func__, obj, "global_map");
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if (map_fd < 0)
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goto err;
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pmu_fd = setup_bpf_perf_event(perf_event_fd);
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if (pmu_fd < 0 || perf_event_mmap(pmu_fd) < 0)
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goto err;
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pthread_create(&tid, NULL, poller_thread, (void *)&pmu_fd);
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sprintf(test_script,
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"/usr/sbin/iptables -A INPUT -p tcp --dport %d -j DROP",
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TESTPORT);
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system(test_script);
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sprintf(test_script,
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"/usr/bin/nc 127.0.0.1 %d < /etc/passwd > /dev/null 2>&1 ",
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TESTPORT);
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system(test_script);
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sprintf(test_script,
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"/usr/sbin/iptables -D INPUT -p tcp --dport %d -j DROP",
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TESTPORT);
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system(test_script);
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rv = bpf_map_lookup_elem(map_fd, &key, &g);
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if (rv != 0) {
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printf("FAILED: bpf_map_lookup_elem returns %d\n", rv);
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goto err;
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}
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sleep(10);
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if (verify_result(&g)) {
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printf("FAILED: Wrong stats Expected %d calls, got %d\n",
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g.ncalls, rx_callbacks);
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goto err;
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}
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printf("PASSED!\n");
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error = 0;
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err:
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bpf_prog_detach(cg_fd, BPF_CGROUP_SOCK_OPS);
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close(cg_fd);
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cleanup_cgroup_environment();
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return error;
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}
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