1/* Copyright (c) 2017 Facebook
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7
8/* This program shows clang/llvm is able to generate code pattern
9 * like:
10 *   _tcp_send_active_reset:
11 *      0:       bf 16 00 00 00 00 00 00         r6 = r1
12 *    ......
13 *    335:       b7 01 00 00 0f 00 00 00         r1 = 15
14 *    336:       05 00 48 00 00 00 00 00         goto 72
15 *
16 *   LBB0_3:
17 *    337:       b7 01 00 00 01 00 00 00         r1 = 1
18 *    338:       63 1a d0 ff 00 00 00 00         *(u32 *)(r10 - 48) = r1
19 *    408:       b7 01 00 00 03 00 00 00         r1 = 3
20 *
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 = r10
24 *    411:       07 07 00 00 b8 ff ff ff         r7 += -72
25 *    412:       bf 73 00 00 00 00 00 00         r3 = r7
26 *    413:       0f 13 00 00 00 00 00 00         r3 += r1
27 *    414:       73 23 2d 00 00 00 00 00         *(u8 *)(r3 + 45) = r2
28 *
29 * From the above code snippet, the code generated by the compiler
30 * is reasonable. The "r1" is assigned to different values in basic
31 * 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 0xBAADBEEF
43
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 for
47 * verifier purpose without bpf program execution.
48 * We can safely mock much simpler data structures, basically
49 * 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_family
77#define sk_v6_daddr		__sk_common.skc_v6_daddr
78#define sk_v6_rcv_saddr		__sk_common.skc_v6_rcv_saddr
79};
80
81struct inet_sock {
82	struct sock		sk;
83#define inet_daddr		sk.__sk_common.skc_daddr
84#define inet_dport		sk.__sk_common.skc_dport
85	__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 = 2
104};
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 for
132 * 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	else
222		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