tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c

   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";