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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - samples/bpf/tcbpf1_kern.c
1 #define KBUILD_MODNAME "foo"
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>
8 #include <uapi/linux/filter.h>
9 #include <uapi/linux/pkt_cls.h>
10 #include "bpf_helpers.h"
12 /* compiler workaround */
13 #define _htonl __builtin_bswap32
15 static inline void set_dst_mac(struct __sk_buff
*skb
, char *mac
)
17 bpf_skb_store_bytes(skb
, 0, mac
, ETH_ALEN
, 1);
20 #define IP_CSUM_OFF (ETH_HLEN + offsetof(struct iphdr, check))
21 #define TOS_OFF (ETH_HLEN + offsetof(struct iphdr, tos))
23 static inline void set_ip_tos(struct __sk_buff
*skb
, __u8 new_tos
)
25 __u8 old_tos
= load_byte(skb
, TOS_OFF
);
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);
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))
34 #define IS_PSEUDO 0x10
36 static inline void set_tcp_ip_src(struct __sk_buff
*skb
, __u32 new_ip
)
38 __u32 old_ip
= _htonl(load_word(skb
, IP_SRC_OFF
));
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);
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
)
48 __u16 old_port
= htons(load_half(skb
, TCP_DPORT_OFF
));
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);
55 int bpf_prog1(struct __sk_buff
*skb
)
57 __u8 proto
= load_byte(skb
, ETH_HLEN
+ offsetof(struct iphdr
, protocol
));
60 if (proto
== IPPROTO_TCP
) {
62 set_tcp_ip_src(skb
, 0xA010101);
63 set_tcp_dest_port(skb
, 5001);
69 int _redirect_xmit(struct __sk_buff
*skb
)
71 return bpf_redirect(skb
->ifindex
+ 1, 0);
74 int _redirect_recv(struct __sk_buff
*skb
)
76 return bpf_redirect(skb
->ifindex
+ 1, 1);
78 SEC("clone_redirect_xmit")
79 int _clone_redirect_xmit(struct __sk_buff
*skb
)
81 bpf_clone_redirect(skb
, skb
->ifindex
+ 1, 0);
84 SEC("clone_redirect_recv")
85 int _clone_redirect_recv(struct __sk_buff
*skb
)
87 bpf_clone_redirect(skb
, skb
->ifindex
+ 1, 1);
90 char _license
[] SEC("license") = "GPL";