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
7 struct 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
17 static __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
31 SEC("sockops")
32 int 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 }
154 char _license[] SEC("license") = "GPL";
155
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