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1/* Copyright (c) 2017 Facebook2 *3 * This program is free software; you can redistribute it and/or4 * modify it under the terms of version 2 of the GNU General Public5 * License as published by the Free Software Foundation.6 */7 8/* This program shows clang/llvm is able to generate code pattern9 * like:10 * _tcp_send_active_reset:11 * 0: bf 16 00 00 00 00 00 00 r6 = r112 * ......13 * 335: b7 01 00 00 0f 00 00 00 r1 = 1514 * 336: 05 00 48 00 00 00 00 00 goto 7215 *16 * LBB0_3:17 * 337: b7 01 00 00 01 00 00 00 r1 = 118 * 338: 63 1a d0 ff 00 00 00 00 *(u32 *)(r10 - 48) = r119 * 408: b7 01 00 00 03 00 00 00 r1 = 320 *21 * LBB0_4:22 * 409: 71 a2 fe ff 00 00 00 00 r2 = *(u8 *)(r10 - 2)23 * 410: bf a7 00 00 00 00 00 00 r7 = r1024 * 411: 07 07 00 00 b8 ff ff ff r7 += -7225 * 412: bf 73 00 00 00 00 00 00 r3 = r726 * 413: 0f 13 00 00 00 00 00 00 r3 += r127 * 414: 73 23 2d 00 00 00 00 00 *(u8 *)(r3 + 45) = r228 *29 * From the above code snippet, the code generated by the compiler30 * is reasonable. The "r1" is assigned to different values in basic31 * blocks "_tcp_send_active_reset" and "LBB0_3", and used in "LBB0_4".32 * The verifier should be able to handle such code patterns.33 */34#include <string.h>35#include <linux/bpf.h>36#include <linux/ipv6.h>37#include <linux/version.h>38#include <sys/socket.h>39#include <bpf/bpf_helpers.h>40 41#define _(P) ({typeof(P) val = 0; bpf_probe_read_kernel(&val, sizeof(val), &P); val;})42#define TCP_ESTATS_MAGIC 0xBAADBEEF43 44/* This test case needs "sock" and "pt_regs" data structure.45 * Recursively, "sock" needs "sock_common" and "inet_sock".46 * However, this is a unit test case only for47 * verifier purpose without bpf program execution.48 * We can safely mock much simpler data structures, basically49 * only taking the necessary fields from kernel headers.50 */51typedef __u32 __bitwise __portpair;52typedef __u64 __bitwise __addrpair;53 54struct sock_common {55 unsigned short skc_family;56 union {57 __addrpair skc_addrpair;58 struct {59 __be32 skc_daddr;60 __be32 skc_rcv_saddr;61 };62 };63 union {64 __portpair skc_portpair;65 struct {66 __be16 skc_dport;67 __u16 skc_num;68 };69 };70 struct in6_addr skc_v6_daddr;71 struct in6_addr skc_v6_rcv_saddr;72};73 74struct sock {75 struct sock_common __sk_common;76#define sk_family __sk_common.skc_family77#define sk_v6_daddr __sk_common.skc_v6_daddr78#define sk_v6_rcv_saddr __sk_common.skc_v6_rcv_saddr79};80 81struct inet_sock {82 struct sock sk;83#define inet_daddr sk.__sk_common.skc_daddr84#define inet_dport sk.__sk_common.skc_dport85 __be32 inet_saddr;86 __be16 inet_sport;87};88 89struct pt_regs {90 long di;91};92 93static inline struct inet_sock *inet_sk(const struct sock *sk)94{95 return (struct inet_sock *)sk;96}97 98/* Define various data structures for state recording.99 * Some fields are not used due to test simplification.100 */101enum tcp_estats_addrtype {102 TCP_ESTATS_ADDRTYPE_IPV4 = 1,103 TCP_ESTATS_ADDRTYPE_IPV6 = 2104};105 106enum tcp_estats_event_type {107 TCP_ESTATS_ESTABLISH,108 TCP_ESTATS_PERIODIC,109 TCP_ESTATS_TIMEOUT,110 TCP_ESTATS_RETRANSMIT_TIMEOUT,111 TCP_ESTATS_RETRANSMIT_OTHER,112 TCP_ESTATS_SYN_RETRANSMIT,113 TCP_ESTATS_SYNACK_RETRANSMIT,114 TCP_ESTATS_TERM,115 TCP_ESTATS_TX_RESET,116 TCP_ESTATS_RX_RESET,117 TCP_ESTATS_WRITE_TIMEOUT,118 TCP_ESTATS_CONN_TIMEOUT,119 TCP_ESTATS_ACK_LATENCY,120 TCP_ESTATS_NEVENTS,121};122 123struct tcp_estats_event {124 int pid;125 int cpu;126 unsigned long ts;127 unsigned int magic;128 enum tcp_estats_event_type event_type;129};130 131/* The below data structure is packed in order for132 * llvm compiler to generate expected code.133 */134struct tcp_estats_conn_id {135 unsigned int localaddressType;136 struct {137 unsigned char data[16];138 } localaddress;139 struct {140 unsigned char data[16];141 } remaddress;142 unsigned short localport;143 unsigned short remport;144} __attribute__((__packed__));145 146struct tcp_estats_basic_event {147 struct tcp_estats_event event;148 struct tcp_estats_conn_id conn_id;149};150 151struct {152 __uint(type, BPF_MAP_TYPE_HASH);153 __uint(max_entries, 1024);154 __type(key, __u32);155 __type(value, struct tcp_estats_basic_event);156} ev_record_map SEC(".maps");157 158struct dummy_tracepoint_args {159 unsigned long long pad;160 struct sock *sock;161};162 163static __always_inline void tcp_estats_ev_init(struct tcp_estats_event *event,164 enum tcp_estats_event_type type)165{166 event->magic = TCP_ESTATS_MAGIC;167 event->ts = bpf_ktime_get_ns();168 event->event_type = type;169}170 171static __always_inline void unaligned_u32_set(unsigned char *to, __u8 *from)172{173 to[0] = _(from[0]);174 to[1] = _(from[1]);175 to[2] = _(from[2]);176 to[3] = _(from[3]);177}178 179static __always_inline void conn_id_ipv4_init(struct tcp_estats_conn_id *conn_id,180 __be32 *saddr, __be32 *daddr)181{182 conn_id->localaddressType = TCP_ESTATS_ADDRTYPE_IPV4;183 184 unaligned_u32_set(conn_id->localaddress.data, (__u8 *)saddr);185 unaligned_u32_set(conn_id->remaddress.data, (__u8 *)daddr);186}187 188static __always_inline void conn_id_ipv6_init(struct tcp_estats_conn_id *conn_id,189 __be32 *saddr, __be32 *daddr)190{191 conn_id->localaddressType = TCP_ESTATS_ADDRTYPE_IPV6;192 193 unaligned_u32_set(conn_id->localaddress.data, (__u8 *)saddr);194 unaligned_u32_set(conn_id->localaddress.data + sizeof(__u32),195 (__u8 *)(saddr + 1));196 unaligned_u32_set(conn_id->localaddress.data + sizeof(__u32) * 2,197 (__u8 *)(saddr + 2));198 unaligned_u32_set(conn_id->localaddress.data + sizeof(__u32) * 3,199 (__u8 *)(saddr + 3));200 201 unaligned_u32_set(conn_id->remaddress.data,202 (__u8 *)(daddr));203 unaligned_u32_set(conn_id->remaddress.data + sizeof(__u32),204 (__u8 *)(daddr + 1));205 unaligned_u32_set(conn_id->remaddress.data + sizeof(__u32) * 2,206 (__u8 *)(daddr + 2));207 unaligned_u32_set(conn_id->remaddress.data + sizeof(__u32) * 3,208 (__u8 *)(daddr + 3));209}210 211static __always_inline void tcp_estats_conn_id_init(struct tcp_estats_conn_id *conn_id,212 struct sock *sk)213{214 conn_id->localport = _(inet_sk(sk)->inet_sport);215 conn_id->remport = _(inet_sk(sk)->inet_dport);216 217 if (_(sk->sk_family) == AF_INET6)218 conn_id_ipv6_init(conn_id,219 sk->sk_v6_rcv_saddr.s6_addr32,220 sk->sk_v6_daddr.s6_addr32);221 else222 conn_id_ipv4_init(conn_id,223 &inet_sk(sk)->inet_saddr,224 &inet_sk(sk)->inet_daddr);225}226 227static __always_inline void tcp_estats_init(struct sock *sk,228 struct tcp_estats_event *event,229 struct tcp_estats_conn_id *conn_id,230 enum tcp_estats_event_type type)231{232 tcp_estats_ev_init(event, type);233 tcp_estats_conn_id_init(conn_id, sk);234}235 236static __always_inline void send_basic_event(struct sock *sk,237 enum tcp_estats_event_type type)238{239 struct tcp_estats_basic_event ev;240 __u32 key = bpf_get_prandom_u32();241 242 memset(&ev, 0, sizeof(ev));243 tcp_estats_init(sk, &ev.event, &ev.conn_id, type);244 bpf_map_update_elem(&ev_record_map, &key, &ev, BPF_ANY);245}246 247SEC("tp/dummy/tracepoint")248int _dummy_tracepoint(struct dummy_tracepoint_args *arg)249{250 if (!arg->sock)251 return 0;252 253 send_basic_event(arg->sock, TCP_ESTATS_TX_RESET);254 return 0;255}256 257char _license[] SEC("license") = "GPL";258