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 
18 struct tcpbpf_globals global = {};
19 int _version SEC("version") = 1;
20 
21 /**
22  * SOL_TCP is defined in <netinet/tcp.h> while
23  * TCP_SAVED_SYN is defined in already included <linux/tcp.h>
24  */
25 #ifndef SOL_TCP
26 #define SOL_TCP 6
27 #endif
28 
29 static __always_inline int get_tp_window_clamp(struct bpf_sock_ops *skops)
30 {
31 	struct bpf_sock *sk;
32 	struct tcp_sock *tp;
33 
34 	sk = skops->sk;
35 	if (!sk)
36 		return -1;
37 	tp = bpf_skc_to_tcp_sock(sk);
38 	if (!tp)
39 		return -1;
40 	return tp->window_clamp;
41 }
42 
43 SEC("sockops")
44 int bpf_testcb(struct bpf_sock_ops *skops)
45 {
46 	char header[sizeof(struct ipv6hdr) + sizeof(struct tcphdr)];
47 	struct bpf_sock_ops *reuse = skops;
48 	struct tcphdr *thdr;
49 	int window_clamp = 9216;
50 	int good_call_rv = 0;
51 	int bad_call_rv = 0;
52 	int save_syn = 1;
53 	int rv = -1;
54 	int v = 0;
55 	int op;
56 
57 	/* Test reading fields in bpf_sock_ops using single register */
58 	asm volatile (
59 		"%[reuse] = *(u32 *)(%[reuse] +96)"
60 		: [reuse] "+r"(reuse)
61 		:);
62 
63 	asm volatile (
64 		"%[op] = *(u32 *)(%[skops] +96)"
65 		: [op] "+r"(op)
66 		: [skops] "r"(skops)
67 		:);
68 
69 	asm volatile (
70 		"r9 = %[skops];\n"
71 		"r8 = *(u32 *)(r9 +164);\n"
72 		"*(u32 *)(r9 +164) = r8;\n"
73 		:: [skops] "r"(skops)
74 		: "r9", "r8");
75 
76 	asm volatile (
77 		"r1 = %[skops];\n"
78 		"r1 = *(u64 *)(r1 +184);\n"
79 		"if r1 == 0 goto +1;\n"
80 		"r1 = *(u32 *)(r1 +4);\n"
81 		:: [skops] "r"(skops):"r1");
82 
83 	asm volatile (
84 		"r9 = %[skops];\n"
85 		"r9 = *(u64 *)(r9 +184);\n"
86 		"if r9 == 0 goto +1;\n"
87 		"r9 = *(u32 *)(r9 +4);\n"
88 		:: [skops] "r"(skops):"r9");
89 
90 	asm volatile (
91 		"r1 = %[skops];\n"
92 		"r2 = *(u64 *)(r1 +184);\n"
93 		"if r2 == 0 goto +1;\n"
94 		"r2 = *(u32 *)(r2 +4);\n"
95 		:: [skops] "r"(skops):"r1", "r2");
96 
97 	op = (int) skops->op;
98 
99 	global.event_map |= (1 << op);
100 
101 	switch (op) {
102 	case BPF_SOCK_OPS_TCP_CONNECT_CB:
103 		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
104 				    &window_clamp, sizeof(window_clamp));
105 		global.window_clamp_client = get_tp_window_clamp(skops);
106 		break;
107 	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
108 		/* Test failure to set largest cb flag (assumes not defined) */
109 		global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops, 0x80);
110 		/* Set callback */
111 		global.good_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
112 						 BPF_SOCK_OPS_STATE_CB_FLAG);
113 		break;
114 	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
115 		skops->sk_txhash = 0x12345f;
116 		v = 0xff;
117 		rv = bpf_setsockopt(skops, SOL_IPV6, IPV6_TCLASS, &v,
118 				    sizeof(v));
119 		if (skops->family == AF_INET6) {
120 			v = bpf_getsockopt(skops, IPPROTO_TCP, TCP_SAVED_SYN,
121 					   header, (sizeof(struct ipv6hdr) +
122 						    sizeof(struct tcphdr)));
123 			if (!v) {
124 				int offset = sizeof(struct ipv6hdr);
125 
126 				thdr = (struct tcphdr *)(header + offset);
127 				v = thdr->syn;
128 
129 				global.tcp_saved_syn = v;
130 			}
131 		}
132 		rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
133 				    &window_clamp, sizeof(window_clamp));
134 
135 		global.window_clamp_server = get_tp_window_clamp(skops);
136 		break;
137 	case BPF_SOCK_OPS_RTO_CB:
138 		break;
139 	case BPF_SOCK_OPS_RETRANS_CB:
140 		break;
141 	case BPF_SOCK_OPS_STATE_CB:
142 		if (skops->args[1] == BPF_TCP_CLOSE) {
143 			if (skops->args[0] == BPF_TCP_LISTEN) {
144 				global.num_listen++;
145 			} else {
146 				global.total_retrans = skops->total_retrans;
147 				global.data_segs_in = skops->data_segs_in;
148 				global.data_segs_out = skops->data_segs_out;
149 				global.bytes_received = skops->bytes_received;
150 				global.bytes_acked = skops->bytes_acked;
151 			}
152 			global.num_close_events++;
153 		}
154 		break;
155 	case BPF_SOCK_OPS_TCP_LISTEN_CB:
156 		bpf_sock_ops_cb_flags_set(skops, BPF_SOCK_OPS_STATE_CB_FLAG);
157 		v = bpf_setsockopt(skops, IPPROTO_TCP, TCP_SAVE_SYN,
158 				   &save_syn, sizeof(save_syn));
159 		/* Update global map w/ result of setsock opt */
160 		global.tcp_save_syn = v;
161 		break;
162 	default:
163 		rv = -1;
164 	}
165 	skops->reply = rv;
166 	return 1;
167 }
168 char _license[] SEC("license") = "GPL";
169