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65d472fb AS |
1 | /* Copyright (c) 2016 Facebook |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | */ | |
96a8eb1e | 7 | #define KBUILD_MODNAME "foo" |
65d472fb | 8 | #include <linux/if_ether.h> |
4d5d33a0 | 9 | #include <linux/if_vlan.h> |
65d472fb AS |
10 | #include <linux/ip.h> |
11 | #include <linux/ipv6.h> | |
12 | #include <linux/in.h> | |
13 | #include <linux/tcp.h> | |
14 | #include <linux/udp.h> | |
15 | #include <uapi/linux/bpf.h> | |
16 | #include <net/ip.h> | |
17 | #include "bpf_helpers.h" | |
18 | ||
19 | #define DEFAULT_PKTGEN_UDP_PORT 9 | |
20 | #define DEBUG 0 | |
21 | ||
22 | static int tcp(void *data, uint64_t tp_off, void *data_end) | |
23 | { | |
24 | struct tcphdr *tcp = data + tp_off; | |
25 | ||
26 | if (tcp + 1 > data_end) | |
27 | return 0; | |
28 | if (tcp->dest == htons(80) || tcp->source == htons(80)) | |
29 | return TC_ACT_SHOT; | |
30 | return 0; | |
31 | } | |
32 | ||
33 | static int udp(void *data, uint64_t tp_off, void *data_end) | |
34 | { | |
35 | struct udphdr *udp = data + tp_off; | |
36 | ||
37 | if (udp + 1 > data_end) | |
38 | return 0; | |
39 | if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) || | |
40 | udp->source == htons(DEFAULT_PKTGEN_UDP_PORT)) { | |
41 | if (DEBUG) { | |
42 | char fmt[] = "udp port 9 indeed\n"; | |
43 | ||
44 | bpf_trace_printk(fmt, sizeof(fmt)); | |
45 | } | |
46 | return TC_ACT_SHOT; | |
47 | } | |
48 | return 0; | |
49 | } | |
50 | ||
51 | static int parse_ipv4(void *data, uint64_t nh_off, void *data_end) | |
52 | { | |
53 | struct iphdr *iph; | |
54 | uint64_t ihl_len; | |
55 | ||
56 | iph = data + nh_off; | |
57 | if (iph + 1 > data_end) | |
58 | return 0; | |
59 | ||
60 | if (ip_is_fragment(iph)) | |
61 | return 0; | |
62 | ihl_len = iph->ihl * 4; | |
63 | ||
64 | if (iph->protocol == IPPROTO_IPIP) { | |
65 | iph = data + nh_off + ihl_len; | |
66 | if (iph + 1 > data_end) | |
67 | return 0; | |
68 | ihl_len += iph->ihl * 4; | |
69 | } | |
70 | ||
71 | if (iph->protocol == IPPROTO_TCP) | |
72 | return tcp(data, nh_off + ihl_len, data_end); | |
73 | else if (iph->protocol == IPPROTO_UDP) | |
74 | return udp(data, nh_off + ihl_len, data_end); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | static int parse_ipv6(void *data, uint64_t nh_off, void *data_end) | |
79 | { | |
80 | struct ipv6hdr *ip6h; | |
81 | struct iphdr *iph; | |
82 | uint64_t ihl_len = sizeof(struct ipv6hdr); | |
83 | uint64_t nexthdr; | |
84 | ||
85 | ip6h = data + nh_off; | |
86 | if (ip6h + 1 > data_end) | |
87 | return 0; | |
88 | ||
89 | nexthdr = ip6h->nexthdr; | |
90 | ||
91 | if (nexthdr == IPPROTO_IPIP) { | |
92 | iph = data + nh_off + ihl_len; | |
93 | if (iph + 1 > data_end) | |
94 | return 0; | |
95 | ihl_len += iph->ihl * 4; | |
96 | nexthdr = iph->protocol; | |
97 | } else if (nexthdr == IPPROTO_IPV6) { | |
98 | ip6h = data + nh_off + ihl_len; | |
99 | if (ip6h + 1 > data_end) | |
100 | return 0; | |
101 | ihl_len += sizeof(struct ipv6hdr); | |
102 | nexthdr = ip6h->nexthdr; | |
103 | } | |
104 | ||
105 | if (nexthdr == IPPROTO_TCP) | |
106 | return tcp(data, nh_off + ihl_len, data_end); | |
107 | else if (nexthdr == IPPROTO_UDP) | |
108 | return udp(data, nh_off + ihl_len, data_end); | |
109 | return 0; | |
110 | } | |
111 | ||
65d472fb AS |
112 | SEC("varlen") |
113 | int handle_ingress(struct __sk_buff *skb) | |
114 | { | |
115 | void *data = (void *)(long)skb->data; | |
116 | struct ethhdr *eth = data; | |
117 | void *data_end = (void *)(long)skb->data_end; | |
118 | uint64_t h_proto, nh_off; | |
119 | ||
120 | nh_off = sizeof(*eth); | |
121 | if (data + nh_off > data_end) | |
122 | return 0; | |
123 | ||
124 | h_proto = eth->h_proto; | |
125 | ||
126 | if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) { | |
127 | struct vlan_hdr *vhdr; | |
128 | ||
129 | vhdr = data + nh_off; | |
130 | nh_off += sizeof(struct vlan_hdr); | |
131 | if (data + nh_off > data_end) | |
132 | return 0; | |
133 | h_proto = vhdr->h_vlan_encapsulated_proto; | |
134 | } | |
135 | if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) { | |
136 | struct vlan_hdr *vhdr; | |
137 | ||
138 | vhdr = data + nh_off; | |
139 | nh_off += sizeof(struct vlan_hdr); | |
140 | if (data + nh_off > data_end) | |
141 | return 0; | |
142 | h_proto = vhdr->h_vlan_encapsulated_proto; | |
143 | } | |
144 | if (h_proto == htons(ETH_P_IP)) | |
145 | return parse_ipv4(data, nh_off, data_end); | |
146 | else if (h_proto == htons(ETH_P_IPV6)) | |
147 | return parse_ipv6(data, nh_off, data_end); | |
148 | return 0; | |
149 | } | |
150 | char _license[] SEC("license") = "GPL"; |