Commit | Line | Data |
---|---|---|
acb4ea95 NS |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (c) 2018 Facebook | |
4 | * | |
5 | * BPF program to automatically reflect TOS option from received syn packet | |
6 | * | |
ea9b6362 | 7 | * Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program. |
acb4ea95 NS |
8 | */ |
9 | ||
10 | #include <uapi/linux/bpf.h> | |
11 | #include <uapi/linux/tcp.h> | |
12 | #include <uapi/linux/if_ether.h> | |
13 | #include <uapi/linux/if_packet.h> | |
14 | #include <uapi/linux/ip.h> | |
15 | #include <uapi/linux/ipv6.h> | |
16 | #include <uapi/linux/in.h> | |
17 | #include <linux/socket.h> | |
7cf245a3 THJ |
18 | #include <bpf/bpf_helpers.h> |
19 | #include <bpf/bpf_endian.h> | |
acb4ea95 NS |
20 | |
21 | #define DEBUG 1 | |
22 | ||
acb4ea95 NS |
23 | SEC("sockops") |
24 | int bpf_basertt(struct bpf_sock_ops *skops) | |
25 | { | |
26 | char header[sizeof(struct ipv6hdr)]; | |
27 | struct ipv6hdr *hdr6; | |
28 | struct iphdr *hdr; | |
29 | int hdr_size = 0; | |
30 | int save_syn = 1; | |
31 | int tos = 0; | |
32 | int rv = 0; | |
33 | int op; | |
34 | ||
35 | op = (int) skops->op; | |
36 | ||
37 | #ifdef DEBUG | |
38 | bpf_printk("BPF command: %d\n", op); | |
39 | #endif | |
40 | switch (op) { | |
41 | case BPF_SOCK_OPS_TCP_LISTEN_CB: | |
42 | rv = bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN, | |
43 | &save_syn, sizeof(save_syn)); | |
44 | break; | |
45 | case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: | |
46 | if (skops->family == AF_INET) | |
47 | hdr_size = sizeof(struct iphdr); | |
48 | else | |
49 | hdr_size = sizeof(struct ipv6hdr); | |
50 | rv = bpf_getsockopt(skops, SOL_TCP, TCP_SAVED_SYN, | |
51 | header, hdr_size); | |
52 | if (!rv) { | |
53 | if (skops->family == AF_INET) { | |
54 | hdr = (struct iphdr *) header; | |
55 | tos = hdr->tos; | |
56 | if (tos != 0) | |
57 | bpf_setsockopt(skops, SOL_IP, IP_TOS, | |
58 | &tos, sizeof(tos)); | |
59 | } else { | |
60 | hdr6 = (struct ipv6hdr *) header; | |
61 | tos = ((hdr6->priority) << 4 | | |
62 | (hdr6->flow_lbl[0]) >> 4); | |
63 | if (tos) | |
64 | bpf_setsockopt(skops, SOL_IPV6, | |
65 | IPV6_TCLASS, | |
66 | &tos, sizeof(tos)); | |
67 | } | |
68 | rv = 0; | |
69 | } | |
70 | break; | |
71 | default: | |
72 | rv = -1; | |
73 | } | |
74 | #ifdef DEBUG | |
75 | bpf_printk("Returning %d\n", rv); | |
76 | #endif | |
77 | skops->reply = rv; | |
78 | return 1; | |
79 | } | |
80 | char _license[] SEC("license") = "GPL"; |