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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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435f90a338
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>
96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
// 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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