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
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
get_tp_window_clamp(struct bpf_sock_ops * skops)28 static __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
42 SEC("sockops")
bpf_testcb(struct bpf_sock_ops * skops)43 int 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 }
165 char _license[] SEC("license") = "GPL";
166