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Commit | Line | Data |
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96a8eb1e | 1 | #define KBUILD_MODNAME "foo" |
91bc4822 AS |
2 | #include <uapi/linux/bpf.h> |
3 | #include <uapi/linux/if_ether.h> | |
4 | #include <uapi/linux/if_packet.h> | |
5 | #include <uapi/linux/ip.h> | |
6 | #include <uapi/linux/in.h> | |
7 | #include <uapi/linux/tcp.h> | |
a166151c | 8 | #include <uapi/linux/filter.h> |
27b29f63 | 9 | #include <uapi/linux/pkt_cls.h> |
91bc4822 AS |
10 | #include "bpf_helpers.h" |
11 | ||
12 | /* compiler workaround */ | |
13 | #define _htonl __builtin_bswap32 | |
14 | ||
15 | static inline void set_dst_mac(struct __sk_buff *skb, char *mac) | |
16 | { | |
17 | bpf_skb_store_bytes(skb, 0, mac, ETH_ALEN, 1); | |
18 | } | |
19 | ||
91bc4822 AS |
20 | #define IP_CSUM_OFF (ETH_HLEN + offsetof(struct iphdr, check)) |
21 | #define TOS_OFF (ETH_HLEN + offsetof(struct iphdr, tos)) | |
22 | ||
23 | static inline void set_ip_tos(struct __sk_buff *skb, __u8 new_tos) | |
24 | { | |
3431205e | 25 | __u8 old_tos = load_byte(skb, TOS_OFF); |
91bc4822 AS |
26 | |
27 | bpf_l3_csum_replace(skb, IP_CSUM_OFF, htons(old_tos), htons(new_tos), 2); | |
28 | bpf_skb_store_bytes(skb, TOS_OFF, &new_tos, sizeof(new_tos), 0); | |
29 | } | |
30 | ||
31 | #define TCP_CSUM_OFF (ETH_HLEN + sizeof(struct iphdr) + offsetof(struct tcphdr, check)) | |
32 | #define IP_SRC_OFF (ETH_HLEN + offsetof(struct iphdr, saddr)) | |
33 | ||
34 | #define IS_PSEUDO 0x10 | |
35 | ||
36 | static inline void set_tcp_ip_src(struct __sk_buff *skb, __u32 new_ip) | |
37 | { | |
3431205e | 38 | __u32 old_ip = _htonl(load_word(skb, IP_SRC_OFF)); |
91bc4822 AS |
39 | |
40 | bpf_l4_csum_replace(skb, TCP_CSUM_OFF, old_ip, new_ip, IS_PSEUDO | sizeof(new_ip)); | |
41 | bpf_l3_csum_replace(skb, IP_CSUM_OFF, old_ip, new_ip, sizeof(new_ip)); | |
42 | bpf_skb_store_bytes(skb, IP_SRC_OFF, &new_ip, sizeof(new_ip), 0); | |
43 | } | |
44 | ||
45 | #define TCP_DPORT_OFF (ETH_HLEN + sizeof(struct iphdr) + offsetof(struct tcphdr, dest)) | |
46 | static inline void set_tcp_dest_port(struct __sk_buff *skb, __u16 new_port) | |
47 | { | |
3431205e | 48 | __u16 old_port = htons(load_half(skb, TCP_DPORT_OFF)); |
91bc4822 AS |
49 | |
50 | bpf_l4_csum_replace(skb, TCP_CSUM_OFF, old_port, new_port, sizeof(new_port)); | |
51 | bpf_skb_store_bytes(skb, TCP_DPORT_OFF, &new_port, sizeof(new_port), 0); | |
52 | } | |
53 | ||
54 | SEC("classifier") | |
55 | int bpf_prog1(struct __sk_buff *skb) | |
56 | { | |
3431205e | 57 | __u8 proto = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)); |
91bc4822 AS |
58 | long *value; |
59 | ||
60 | if (proto == IPPROTO_TCP) { | |
61 | set_ip_tos(skb, 8); | |
62 | set_tcp_ip_src(skb, 0xA010101); | |
63 | set_tcp_dest_port(skb, 5001); | |
64 | } | |
65 | ||
66 | return 0; | |
67 | } | |
27b29f63 AS |
68 | SEC("redirect_xmit") |
69 | int _redirect_xmit(struct __sk_buff *skb) | |
70 | { | |
71 | return bpf_redirect(skb->ifindex + 1, 0); | |
72 | } | |
73 | SEC("redirect_recv") | |
74 | int _redirect_recv(struct __sk_buff *skb) | |
75 | { | |
76 | return bpf_redirect(skb->ifindex + 1, 1); | |
77 | } | |
78 | SEC("clone_redirect_xmit") | |
79 | int _clone_redirect_xmit(struct __sk_buff *skb) | |
80 | { | |
81 | bpf_clone_redirect(skb, skb->ifindex + 1, 0); | |
82 | return TC_ACT_SHOT; | |
83 | } | |
84 | SEC("clone_redirect_recv") | |
85 | int _clone_redirect_recv(struct __sk_buff *skb) | |
86 | { | |
87 | bpf_clone_redirect(skb, skb->ifindex + 1, 1); | |
88 | return TC_ACT_SHOT; | |
89 | } | |
91bc4822 | 90 | char _license[] SEC("license") = "GPL"; |