1// SPDX-License-Identifier: GPL-2.0
2#include <stddef.h>
3#include <string.h>
4#include <netinet/in.h>
5#include <linux/bpf.h>
6#include <linux/if_ether.h>
7#include <linux/if_packet.h>
8#include <linux/ip.h>
9#include <linux/ipv6.h>
10#include <linux/types.h>
11#include <linux/socket.h>
12#include <linux/tcp.h>
13#include <bpf/bpf_helpers.h>
14#include <bpf/bpf_endian.h>
15#include "bpf_tcp_helpers.h"
16#include "test_tcpbpf.h"
17
18struct tcpbpf_globals global = {};
19
20/**
21 * SOL_TCP is defined in <netinet/tcp.h> while
22 * TCP_SAVED_SYN is defined in already included <linux/tcp.h>
23 */
24#ifndef SOL_TCP
25#define SOL_TCP 6
26#endif
27
28static __always_inline int get_tp_window_clamp(struct bpf_sock_ops *skops)
29{
30	struct bpf_sock *sk;
31	struct tcp_sock *tp;
32
33	sk = skops->sk;
34	if (!sk)
35		return -1;
36	tp = bpf_skc_to_tcp_sock(sk);
37	if (!tp)
38		return -1;
39	return tp->window_clamp;
40}
41
42SEC("sockops")
43int bpf_testcb(struct bpf_sock_ops *skops)
44{
45	char header[sizeof(struct ipv6hdr) + sizeof(struct tcphdr)];
46	struct bpf_sock_ops *reuse = skops;
47	struct tcphdr *thdr;
48	int window_clamp = 9216;
49	int save_syn = 1;
50	int rv = -1;
51	int v = 0;
52	int op;
53
54	/* Test reading fields in bpf_sock_ops using single register */
55	asm volatile (
56		"%[reuse] = *(u32 *)(%[reuse] +96)"
57		: [reuse] "+r"(reuse)
58		:);
59
60	asm volatile (
61		"%[op] = *(u32 *)(%[skops] +96)"
62		: [op] "=r"(op)
63		: [skops] "r"(skops)
64		:);
65
66	asm volatile (
67		"r9 = %[skops];\n"
68		"r8 = *(u32 *)(r9 +164);\n"
69		"*(u32 *)(r9 +164) = r8;\n"
70		:: [skops] "r"(skops)
71		: "r9", "r8");
72
73	asm volatile (
74		"r1 = %[skops];\n"
75		"r1 = *(u64 *)(r1 +184);\n"
76		"if r1 == 0 goto +1;\n"
77		"r1 = *(u32 *)(r1 +4);\n"
78		:: [skops] "r"(skops):"r1");
79
80	asm volatile (
81		"r9 = %[skops];\n"
82		"r9 = *(u64 *)(r9 +184);\n"
83		"if r9 == 0 goto +1;\n"
84		"r9 = *(u32 *)(r9 +4);\n"
85		:: [skops] "r"(skops):"r9");
86
87	asm volatile (
88		"r1 = %[skops];\n"
89		"r2 = *(u64 *)(r1 +184);\n"
90		"if r2 == 0 goto +1;\n"
91		"r2 = *(u32 *)(r2 +4);\n"
92		:: [skops] "r"(skops):"r1", "r2");
93
94	op = (int) skops->op;
95
96	global.event_map |= (1 << op);
97
98	switch (op) {
99	case BPF_SOCK_OPS_TCP_CONNECT_CB:
100		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
101				    &window_clamp, sizeof(window_clamp));
102		global.window_clamp_client = get_tp_window_clamp(skops);
103		break;
104	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
105		/* Test failure to set largest cb flag (assumes not defined) */
106		global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops, 0x80);
107		/* Set callback */
108		global.good_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
109						 BPF_SOCK_OPS_STATE_CB_FLAG);
110		break;
111	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
112		skops->sk_txhash = 0x12345f;
113		v = 0xff;
114		rv = bpf_setsockopt(skops, SOL_IPV6, IPV6_TCLASS, &v,
115				    sizeof(v));
116		if (skops->family == AF_INET6) {
117			v = bpf_getsockopt(skops, IPPROTO_TCP, TCP_SAVED_SYN,
118					   header, (sizeof(struct ipv6hdr) +
119						    sizeof(struct tcphdr)));
120			if (!v) {
121				int offset = sizeof(struct ipv6hdr);
122
123				thdr = (struct tcphdr *)(header + offset);
124				v = thdr->syn;
125
126				global.tcp_saved_syn = v;
127			}
128		}
129		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
130				    &window_clamp, sizeof(window_clamp));
131
132		global.window_clamp_server = get_tp_window_clamp(skops);
133		break;
134	case BPF_SOCK_OPS_RTO_CB:
135		break;
136	case BPF_SOCK_OPS_RETRANS_CB:
137		break;
138	case BPF_SOCK_OPS_STATE_CB:
139		if (skops->args[1] == BPF_TCP_CLOSE) {
140			if (skops->args[0] == BPF_TCP_LISTEN) {
141				global.num_listen++;
142			} else {
143				global.total_retrans = skops->total_retrans;
144				global.data_segs_in = skops->data_segs_in;
145				global.data_segs_out = skops->data_segs_out;
146				global.bytes_received = skops->bytes_received;
147				global.bytes_acked = skops->bytes_acked;
148			}
149			global.num_close_events++;
150		}
151		break;
152	case BPF_SOCK_OPS_TCP_LISTEN_CB:
153		bpf_sock_ops_cb_flags_set(skops, BPF_SOCK_OPS_STATE_CB_FLAG);
154		v = bpf_setsockopt(skops, IPPROTO_TCP, TCP_SAVE_SYN,
155				   &save_syn, sizeof(save_syn));
156		/* Update global map w/ result of setsock opt */
157		global.tcp_save_syn = v;
158		break;
159	default:
160		rv = -1;
161	}
162	skops->reply = rv;
163	return 1;
164}
165char _license[] SEC("license") = "GPL";
166