1// SPDX-License-Identifier: GPL-2.0
2#include "bpf_tracing_net.h"
3#include <bpf/bpf_helpers.h>
4#include <bpf/bpf_endian.h>
5#include "test_tcpbpf.h"
6
7struct tcpbpf_globals global = {};
8
9/**
10 * SOL_TCP is defined in <netinet/tcp.h> while
11 * TCP_SAVED_SYN is defined in already included <linux/tcp.h>
12 */
13#ifndef SOL_TCP
14#define SOL_TCP 6
15#endif
16
17static __always_inline int get_tp_window_clamp(struct bpf_sock_ops *skops)
18{
19	struct bpf_sock *sk;
20	struct tcp_sock *tp;
21
22	sk = skops->sk;
23	if (!sk)
24		return -1;
25	tp = bpf_skc_to_tcp_sock(sk);
26	if (!tp)
27		return -1;
28	return tp->window_clamp;
29}
30
31SEC("sockops")
32int bpf_testcb(struct bpf_sock_ops *skops)
33{
34	char header[sizeof(struct ipv6hdr) + sizeof(struct tcphdr)];
35	struct bpf_sock_ops *reuse = skops;
36	struct tcphdr *thdr;
37	int window_clamp = 9216;
38	int save_syn = 1;
39	int rv = -1;
40	int v = 0;
41	int op;
42
43	/* Test reading fields in bpf_sock_ops using single register */
44	asm volatile (
45		"%[reuse] = *(u32 *)(%[reuse] +96)"
46		: [reuse] "+r"(reuse)
47		:);
48
49	asm volatile (
50		"%[op] = *(u32 *)(%[skops] +96)"
51		: [op] "=r"(op)
52		: [skops] "r"(skops)
53		:);
54
55	asm volatile (
56		"r9 = %[skops];\n"
57		"r8 = *(u32 *)(r9 +164);\n"
58		"*(u32 *)(r9 +164) = r8;\n"
59		:: [skops] "r"(skops)
60		: "r9", "r8");
61
62	asm volatile (
63		"r1 = %[skops];\n"
64		"r1 = *(u64 *)(r1 +184);\n"
65		"if r1 == 0 goto +1;\n"
66		"r1 = *(u32 *)(r1 +4);\n"
67		:: [skops] "r"(skops):"r1");
68
69	asm volatile (
70		"r9 = %[skops];\n"
71		"r9 = *(u64 *)(r9 +184);\n"
72		"if r9 == 0 goto +1;\n"
73		"r9 = *(u32 *)(r9 +4);\n"
74		:: [skops] "r"(skops):"r9");
75
76	asm volatile (
77		"r1 = %[skops];\n"
78		"r2 = *(u64 *)(r1 +184);\n"
79		"if r2 == 0 goto +1;\n"
80		"r2 = *(u32 *)(r2 +4);\n"
81		:: [skops] "r"(skops):"r1", "r2");
82
83	op = (int) skops->op;
84
85	global.event_map |= (1 << op);
86
87	switch (op) {
88	case BPF_SOCK_OPS_TCP_CONNECT_CB:
89		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
90				    &window_clamp, sizeof(window_clamp));
91		global.window_clamp_client = get_tp_window_clamp(skops);
92		break;
93	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
94		/* Test failure to set largest cb flag (assumes not defined) */
95		global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops, 0x80);
96		/* Set callback */
97		global.good_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
98						 BPF_SOCK_OPS_STATE_CB_FLAG);
99		break;
100	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
101		skops->sk_txhash = 0x12345f;
102		v = 0xff;
103		rv = bpf_setsockopt(skops, SOL_IPV6, IPV6_TCLASS, &v,
104				    sizeof(v));
105		if (skops->family == AF_INET6) {
106			v = bpf_getsockopt(skops, IPPROTO_TCP, TCP_SAVED_SYN,
107					   header, (sizeof(struct ipv6hdr) +
108						    sizeof(struct tcphdr)));
109			if (!v) {
110				int offset = sizeof(struct ipv6hdr);
111
112				thdr = (struct tcphdr *)(header + offset);
113				v = thdr->syn;
114
115				global.tcp_saved_syn = v;
116			}
117		}
118		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
119				    &window_clamp, sizeof(window_clamp));
120
121		global.window_clamp_server = get_tp_window_clamp(skops);
122		break;
123	case BPF_SOCK_OPS_RTO_CB:
124		break;
125	case BPF_SOCK_OPS_RETRANS_CB:
126		break;
127	case BPF_SOCK_OPS_STATE_CB:
128		if (skops->args[1] == BPF_TCP_CLOSE) {
129			if (skops->args[0] == BPF_TCP_LISTEN) {
130				global.num_listen++;
131			} else {
132				global.total_retrans = skops->total_retrans;
133				global.data_segs_in = skops->data_segs_in;
134				global.data_segs_out = skops->data_segs_out;
135				global.bytes_received = skops->bytes_received;
136				global.bytes_acked = skops->bytes_acked;
137			}
138			global.num_close_events++;
139		}
140		break;
141	case BPF_SOCK_OPS_TCP_LISTEN_CB:
142		bpf_sock_ops_cb_flags_set(skops, BPF_SOCK_OPS_STATE_CB_FLAG);
143		v = bpf_setsockopt(skops, IPPROTO_TCP, TCP_SAVE_SYN,
144				   &save_syn, sizeof(save_syn));
145		/* Update global map w/ result of setsock opt */
146		global.tcp_save_syn = v;
147		break;
148	default:
149		rv = -1;
150	}
151	skops->reply = rv;
152	return 1;
153}
154char _license[] SEC("license") = "GPL";
155