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13#include <uapi/linux/bpf.h>
14#include <uapi/linux/tcp.h>
15#include <uapi/linux/if_ether.h>
16#include <uapi/linux/if_packet.h>
17#include <uapi/linux/ip.h>
18#include <linux/socket.h>
19#include <bpf/bpf_helpers.h>
20#include <bpf/bpf_endian.h>
21
22#define DEBUG 1
23
24SEC("sockops")
25int bpf_cong(struct bpf_sock_ops *skops)
26{
27 char cong[] = "dctcp";
28 int rv = 0;
29 int op;
30
31
32
33
34 if (bpf_ntohl(skops->remote_port) != 55601 &&
35 skops->local_port != 55601) {
36 skops->reply = -1;
37 return 1;
38 }
39
40 op = (int) skops->op;
41
42#ifdef DEBUG
43 bpf_printk("BPF command: %d\n", op);
44#endif
45
46
47
48
49
50 if (skops->family == AF_INET6 &&
51 skops->local_ip6[0] == skops->remote_ip6[0] &&
52 (bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) ==
53 (bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) {
54 switch (op) {
55 case BPF_SOCK_OPS_NEEDS_ECN:
56 rv = 1;
57 break;
58 case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
59 rv = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION,
60 cong, sizeof(cong));
61 break;
62 case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
63 rv = bpf_setsockopt(skops, SOL_TCP, TCP_CONGESTION,
64 cong, sizeof(cong));
65 break;
66 default:
67 rv = -1;
68 }
69 } else {
70 rv = -1;
71 }
72#ifdef DEBUG
73 bpf_printk("Returning %d\n", rv);
74#endif
75 skops->reply = rv;
76 return 1;
77}
78char _license[] SEC("license") = "GPL";
79