/* Copyright (c) 2016 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#define KBUILD_MODNAME "foo"
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#include <uapi/linux/bpf.h>
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#include <uapi/linux/if_ether.h>
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#include <uapi/linux/if_packet.h>
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#include <uapi/linux/ip.h>
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#include <uapi/linux/ipv6.h>
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#include <uapi/linux/in.h>
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#include <uapi/linux/tcp.h>
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#include <uapi/linux/filter.h>
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#include <uapi/linux/pkt_cls.h>
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#include <net/ipv6.h>
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#include <bpf/bpf_helpers.h>
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#define _htonl __builtin_bswap32
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#define PIN_GLOBAL_NS 2
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struct bpf_elf_map {
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__u32 type;
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__u32 size_key;
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__u32 size_value;
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__u32 max_elem;
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__u32 flags;
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__u32 id;
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__u32 pinning;
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};
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/* copy of 'struct ethhdr' without __packed */
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struct eth_hdr {
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unsigned char h_dest[ETH_ALEN];
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unsigned char h_source[ETH_ALEN];
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unsigned short h_proto;
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};
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struct bpf_elf_map SEC("maps") tun_iface = {
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.type = BPF_MAP_TYPE_ARRAY,
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.size_key = sizeof(int),
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.size_value = sizeof(int),
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.pinning = PIN_GLOBAL_NS,
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.max_elem = 1,
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};
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static __always_inline bool is_vip_addr(__be16 eth_proto, __be32 daddr)
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{
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if (eth_proto == htons(ETH_P_IP))
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return (_htonl(0xffffff00) & daddr) == _htonl(0x0a0a0100);
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else if (eth_proto == htons(ETH_P_IPV6))
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return (daddr == _htonl(0x2401face));
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return false;
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}
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SEC("l2_to_iptun_ingress_forward")
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int _l2_to_iptun_ingress_forward(struct __sk_buff *skb)
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{
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struct bpf_tunnel_key tkey = {};
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void *data = (void *)(long)skb->data;
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struct eth_hdr *eth = data;
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void *data_end = (void *)(long)skb->data_end;
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int key = 0, *ifindex;
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int ret;
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if (data + sizeof(*eth) > data_end)
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return TC_ACT_OK;
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ifindex = bpf_map_lookup_elem(&tun_iface, &key);
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if (!ifindex)
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return TC_ACT_OK;
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if (eth->h_proto == htons(ETH_P_IP)) {
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char fmt4[] = "ingress forward to ifindex:%d daddr4:%x\n";
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struct iphdr *iph = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*iph) > data_end)
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return TC_ACT_OK;
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if (iph->protocol != IPPROTO_IPIP)
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return TC_ACT_OK;
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bpf_trace_printk(fmt4, sizeof(fmt4), *ifindex,
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_htonl(iph->daddr));
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return bpf_redirect(*ifindex, BPF_F_INGRESS);
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} else if (eth->h_proto == htons(ETH_P_IPV6)) {
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char fmt6[] = "ingress forward to ifindex:%d daddr6:%x::%x\n";
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struct ipv6hdr *ip6h = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
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return TC_ACT_OK;
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if (ip6h->nexthdr != IPPROTO_IPIP &&
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ip6h->nexthdr != IPPROTO_IPV6)
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return TC_ACT_OK;
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bpf_trace_printk(fmt6, sizeof(fmt6), *ifindex,
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_htonl(ip6h->daddr.s6_addr32[0]),
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_htonl(ip6h->daddr.s6_addr32[3]));
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return bpf_redirect(*ifindex, BPF_F_INGRESS);
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}
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return TC_ACT_OK;
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}
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SEC("l2_to_iptun_ingress_redirect")
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int _l2_to_iptun_ingress_redirect(struct __sk_buff *skb)
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{
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struct bpf_tunnel_key tkey = {};
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void *data = (void *)(long)skb->data;
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struct eth_hdr *eth = data;
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void *data_end = (void *)(long)skb->data_end;
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int key = 0, *ifindex;
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int ret;
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if (data + sizeof(*eth) > data_end)
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return TC_ACT_OK;
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ifindex = bpf_map_lookup_elem(&tun_iface, &key);
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if (!ifindex)
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return TC_ACT_OK;
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if (eth->h_proto == htons(ETH_P_IP)) {
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char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n";
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struct iphdr *iph = data + sizeof(*eth);
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__be32 daddr = iph->daddr;
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if (data + sizeof(*eth) + sizeof(*iph) > data_end)
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return TC_ACT_OK;
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if (!is_vip_addr(eth->h_proto, daddr))
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return TC_ACT_OK;
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bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(daddr), *ifindex);
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} else {
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return TC_ACT_OK;
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}
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tkey.tunnel_id = 10000;
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tkey.tunnel_ttl = 64;
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tkey.remote_ipv4 = 0x0a020166; /* 10.2.1.102 */
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bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), 0);
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return bpf_redirect(*ifindex, 0);
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}
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SEC("l2_to_ip6tun_ingress_redirect")
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int _l2_to_ip6tun_ingress_redirect(struct __sk_buff *skb)
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{
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struct bpf_tunnel_key tkey = {};
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void *data = (void *)(long)skb->data;
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struct eth_hdr *eth = data;
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void *data_end = (void *)(long)skb->data_end;
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int key = 0, *ifindex;
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if (data + sizeof(*eth) > data_end)
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return TC_ACT_OK;
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ifindex = bpf_map_lookup_elem(&tun_iface, &key);
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if (!ifindex)
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return TC_ACT_OK;
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if (eth->h_proto == htons(ETH_P_IP)) {
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char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n";
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struct iphdr *iph = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*iph) > data_end)
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return TC_ACT_OK;
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if (!is_vip_addr(eth->h_proto, iph->daddr))
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return TC_ACT_OK;
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bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(iph->daddr),
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*ifindex);
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} else if (eth->h_proto == htons(ETH_P_IPV6)) {
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char fmt6[] = "e/ingress redirect daddr6:%x to ifindex:%d\n";
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struct ipv6hdr *ip6h = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
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return TC_ACT_OK;
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if (!is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0]))
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return TC_ACT_OK;
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bpf_trace_printk(fmt6, sizeof(fmt6),
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_htonl(ip6h->daddr.s6_addr32[0]), *ifindex);
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} else {
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return TC_ACT_OK;
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}
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tkey.tunnel_id = 10000;
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tkey.tunnel_ttl = 64;
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/* 2401:db02:0:0:0:0:0:66 */
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tkey.remote_ipv6[0] = _htonl(0x2401db02);
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tkey.remote_ipv6[1] = 0;
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tkey.remote_ipv6[2] = 0;
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tkey.remote_ipv6[3] = _htonl(0x00000066);
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bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), BPF_F_TUNINFO_IPV6);
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return bpf_redirect(*ifindex, 0);
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}
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SEC("drop_non_tun_vip")
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int _drop_non_tun_vip(struct __sk_buff *skb)
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{
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struct bpf_tunnel_key tkey = {};
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void *data = (void *)(long)skb->data;
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struct eth_hdr *eth = data;
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void *data_end = (void *)(long)skb->data_end;
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if (data + sizeof(*eth) > data_end)
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return TC_ACT_OK;
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if (eth->h_proto == htons(ETH_P_IP)) {
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struct iphdr *iph = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*iph) > data_end)
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return TC_ACT_OK;
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if (is_vip_addr(eth->h_proto, iph->daddr))
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return TC_ACT_SHOT;
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} else if (eth->h_proto == htons(ETH_P_IPV6)) {
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struct ipv6hdr *ip6h = data + sizeof(*eth);
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if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
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return TC_ACT_OK;
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if (is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0]))
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return TC_ACT_SHOT;
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}
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return TC_ACT_OK;
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}
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char _license[] SEC("license") = "GPL";
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