1 /* Copyright (c) 2016 Facebook
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.
7 #include <linux/if_ether.h>
9 #include <linux/ipv6.h>
11 #include <linux/tcp.h>
12 #include <linux/udp.h>
13 #include <uapi/linux/bpf.h>
15 #include "bpf_helpers.h"
17 #define DEFAULT_PKTGEN_UDP_PORT 9
20 static int tcp(void *data, uint64_t tp_off, void *data_end)
22 struct tcphdr *tcp = data + tp_off;
24 if (tcp + 1 > data_end)
26 if (tcp->dest == htons(80) || tcp->source == htons(80))
31 static int udp(void *data, uint64_t tp_off, void *data_end)
33 struct udphdr *udp = data + tp_off;
35 if (udp + 1 > data_end)
37 if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT) ||
38 udp->source == htons(DEFAULT_PKTGEN_UDP_PORT)) {
40 char fmt[] = "udp port 9 indeed\n";
42 bpf_trace_printk(fmt, sizeof(fmt));
49 static int parse_ipv4(void *data, uint64_t nh_off, void *data_end)
55 if (iph + 1 > data_end)
58 if (ip_is_fragment(iph))
60 ihl_len = iph->ihl * 4;
62 if (iph->protocol == IPPROTO_IPIP) {
63 iph = data + nh_off + ihl_len;
64 if (iph + 1 > data_end)
66 ihl_len += iph->ihl * 4;
69 if (iph->protocol == IPPROTO_TCP)
70 return tcp(data, nh_off + ihl_len, data_end);
71 else if (iph->protocol == IPPROTO_UDP)
72 return udp(data, nh_off + ihl_len, data_end);
76 static int parse_ipv6(void *data, uint64_t nh_off, void *data_end)
80 uint64_t ihl_len = sizeof(struct ipv6hdr);
84 if (ip6h + 1 > data_end)
87 nexthdr = ip6h->nexthdr;
89 if (nexthdr == IPPROTO_IPIP) {
90 iph = data + nh_off + ihl_len;
91 if (iph + 1 > data_end)
93 ihl_len += iph->ihl * 4;
94 nexthdr = iph->protocol;
95 } else if (nexthdr == IPPROTO_IPV6) {
96 ip6h = data + nh_off + ihl_len;
97 if (ip6h + 1 > data_end)
99 ihl_len += sizeof(struct ipv6hdr);
100 nexthdr = ip6h->nexthdr;
103 if (nexthdr == IPPROTO_TCP)
104 return tcp(data, nh_off + ihl_len, data_end);
105 else if (nexthdr == IPPROTO_UDP)
106 return udp(data, nh_off + ihl_len, data_end);
112 uint16_t h_vlan_encapsulated_proto;
116 int handle_ingress(struct __sk_buff *skb)
118 void *data = (void *)(long)skb->data;
119 struct ethhdr *eth = data;
120 void *data_end = (void *)(long)skb->data_end;
121 uint64_t h_proto, nh_off;
123 nh_off = sizeof(*eth);
124 if (data + nh_off > data_end)
127 h_proto = eth->h_proto;
129 if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
130 struct vlan_hdr *vhdr;
132 vhdr = data + nh_off;
133 nh_off += sizeof(struct vlan_hdr);
134 if (data + nh_off > data_end)
136 h_proto = vhdr->h_vlan_encapsulated_proto;
138 if (h_proto == ETH_P_8021Q || h_proto == ETH_P_8021AD) {
139 struct vlan_hdr *vhdr;
141 vhdr = data + nh_off;
142 nh_off += sizeof(struct vlan_hdr);
143 if (data + nh_off > data_end)
145 h_proto = vhdr->h_vlan_encapsulated_proto;
147 if (h_proto == htons(ETH_P_IP))
148 return parse_ipv4(data, nh_off, data_end);
149 else if (h_proto == htons(ETH_P_IPV6))
150 return parse_ipv6(data, nh_off, data_end);
153 char _license[] SEC("license") = "GPL";