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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - samples/bpf/tcbpf1_kern.c
1 #include <uapi/linux/bpf.h>
2 #include <uapi/linux/if_ether.h>
3 #include <uapi/linux/if_packet.h>
4 #include <uapi/linux/ip.h>
5 #include <uapi/linux/in.h>
6 #include <uapi/linux/tcp.h>
7 #include "bpf_helpers.h"
9 /* compiler workaround */
10 #define _htonl __builtin_bswap32
12 static inline void set_dst_mac(struct __sk_buff
*skb
, char *mac
)
14 bpf_skb_store_bytes(skb
, 0, mac
, ETH_ALEN
, 1);
17 /* use 1 below for ingress qdisc and 0 for egress */
23 #define IP_CSUM_OFF (ETH_HLEN + offsetof(struct iphdr, check))
24 #define TOS_OFF (ETH_HLEN + offsetof(struct iphdr, tos))
26 static inline void set_ip_tos(struct __sk_buff
*skb
, __u8 new_tos
)
28 __u8 old_tos
= load_byte(skb
, TOS_OFF
);
30 bpf_l3_csum_replace(skb
, IP_CSUM_OFF
, htons(old_tos
), htons(new_tos
), 2);
31 bpf_skb_store_bytes(skb
, TOS_OFF
, &new_tos
, sizeof(new_tos
), 0);
34 #define TCP_CSUM_OFF (ETH_HLEN + sizeof(struct iphdr) + offsetof(struct tcphdr, check))
35 #define IP_SRC_OFF (ETH_HLEN + offsetof(struct iphdr, saddr))
37 #define IS_PSEUDO 0x10
39 static inline void set_tcp_ip_src(struct __sk_buff
*skb
, __u32 new_ip
)
41 __u32 old_ip
= _htonl(load_word(skb
, IP_SRC_OFF
));
43 bpf_l4_csum_replace(skb
, TCP_CSUM_OFF
, old_ip
, new_ip
, IS_PSEUDO
| sizeof(new_ip
));
44 bpf_l3_csum_replace(skb
, IP_CSUM_OFF
, old_ip
, new_ip
, sizeof(new_ip
));
45 bpf_skb_store_bytes(skb
, IP_SRC_OFF
, &new_ip
, sizeof(new_ip
), 0);
48 #define TCP_DPORT_OFF (ETH_HLEN + sizeof(struct iphdr) + offsetof(struct tcphdr, dest))
49 static inline void set_tcp_dest_port(struct __sk_buff
*skb
, __u16 new_port
)
51 __u16 old_port
= htons(load_half(skb
, TCP_DPORT_OFF
));
53 bpf_l4_csum_replace(skb
, TCP_CSUM_OFF
, old_port
, new_port
, sizeof(new_port
));
54 bpf_skb_store_bytes(skb
, TCP_DPORT_OFF
, &new_port
, sizeof(new_port
), 0);
58 int bpf_prog1(struct __sk_buff
*skb
)
60 __u8 proto
= load_byte(skb
, ETH_HLEN
+ offsetof(struct iphdr
, protocol
));
63 if (proto
== IPPROTO_TCP
) {
65 set_tcp_ip_src(skb
, 0xA010101);
66 set_tcp_dest_port(skb
, 5001);
71 char _license
[] SEC("license") = "GPL";