aboutsummaryrefslogtreecommitdiffstats
path: root/samples/bpf/tc_l2_redirect_kern.c
diff options
context:
space:
mode:
Diffstat (limited to 'samples/bpf/tc_l2_redirect_kern.c')
-rw-r--r--samples/bpf/tc_l2_redirect_kern.c236
1 files changed, 236 insertions, 0 deletions
diff --git a/samples/bpf/tc_l2_redirect_kern.c b/samples/bpf/tc_l2_redirect_kern.c
new file mode 100644
index 000000000000..92a44729dbe4
--- /dev/null
+++ b/samples/bpf/tc_l2_redirect_kern.c
@@ -0,0 +1,236 @@
+/* Copyright (c) 2016 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include <uapi/linux/ipv6.h>
+#include <uapi/linux/in.h>
+#include <uapi/linux/tcp.h>
+#include <uapi/linux/filter.h>
+#include <uapi/linux/pkt_cls.h>
+#include <net/ipv6.h>
+#include "bpf_helpers.h"
+
+#define _htonl __builtin_bswap32
+
+#define PIN_GLOBAL_NS 2
+struct bpf_elf_map {
+ __u32 type;
+ __u32 size_key;
+ __u32 size_value;
+ __u32 max_elem;
+ __u32 flags;
+ __u32 id;
+ __u32 pinning;
+};
+
+/* copy of 'struct ethhdr' without __packed */
+struct eth_hdr {
+ unsigned char h_dest[ETH_ALEN];
+ unsigned char h_source[ETH_ALEN];
+ unsigned short h_proto;
+};
+
+struct bpf_elf_map SEC("maps") tun_iface = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .size_key = sizeof(int),
+ .size_value = sizeof(int),
+ .pinning = PIN_GLOBAL_NS,
+ .max_elem = 1,
+};
+
+static __always_inline bool is_vip_addr(__be16 eth_proto, __be32 daddr)
+{
+ if (eth_proto == htons(ETH_P_IP))
+ return (_htonl(0xffffff00) & daddr) == _htonl(0x0a0a0100);
+ else if (eth_proto == htons(ETH_P_IPV6))
+ return (daddr == _htonl(0x2401face));
+
+ return false;
+}
+
+SEC("l2_to_iptun_ingress_forward")
+int _l2_to_iptun_ingress_forward(struct __sk_buff *skb)
+{
+ struct bpf_tunnel_key tkey = {};
+ void *data = (void *)(long)skb->data;
+ struct eth_hdr *eth = data;
+ void *data_end = (void *)(long)skb->data_end;
+ int key = 0, *ifindex;
+
+ int ret;
+
+ if (data + sizeof(*eth) > data_end)
+ return TC_ACT_OK;
+
+ ifindex = bpf_map_lookup_elem(&tun_iface, &key);
+ if (!ifindex)
+ return TC_ACT_OK;
+
+ if (eth->h_proto == htons(ETH_P_IP)) {
+ char fmt4[] = "ingress forward to ifindex:%d daddr4:%x\n";
+ struct iphdr *iph = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*iph) > data_end)
+ return TC_ACT_OK;
+
+ if (iph->protocol != IPPROTO_IPIP)
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt4, sizeof(fmt4), *ifindex,
+ _htonl(iph->daddr));
+ return bpf_redirect(*ifindex, BPF_F_INGRESS);
+ } else if (eth->h_proto == htons(ETH_P_IPV6)) {
+ char fmt6[] = "ingress forward to ifindex:%d daddr6:%x::%x\n";
+ struct ipv6hdr *ip6h = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
+ return TC_ACT_OK;
+
+ if (ip6h->nexthdr != IPPROTO_IPIP &&
+ ip6h->nexthdr != IPPROTO_IPV6)
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt6, sizeof(fmt6), *ifindex,
+ _htonl(ip6h->daddr.s6_addr32[0]),
+ _htonl(ip6h->daddr.s6_addr32[3]));
+ return bpf_redirect(*ifindex, BPF_F_INGRESS);
+ }
+
+ return TC_ACT_OK;
+}
+
+SEC("l2_to_iptun_ingress_redirect")
+int _l2_to_iptun_ingress_redirect(struct __sk_buff *skb)
+{
+ struct bpf_tunnel_key tkey = {};
+ void *data = (void *)(long)skb->data;
+ struct eth_hdr *eth = data;
+ void *data_end = (void *)(long)skb->data_end;
+ int key = 0, *ifindex;
+
+ int ret;
+
+ if (data + sizeof(*eth) > data_end)
+ return TC_ACT_OK;
+
+ ifindex = bpf_map_lookup_elem(&tun_iface, &key);
+ if (!ifindex)
+ return TC_ACT_OK;
+
+ if (eth->h_proto == htons(ETH_P_IP)) {
+ char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n";
+ struct iphdr *iph = data + sizeof(*eth);
+ __be32 daddr = iph->daddr;
+
+ if (data + sizeof(*eth) + sizeof(*iph) > data_end)
+ return TC_ACT_OK;
+
+ if (!is_vip_addr(eth->h_proto, daddr))
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(daddr), *ifindex);
+ } else {
+ return TC_ACT_OK;
+ }
+
+ tkey.tunnel_id = 10000;
+ tkey.tunnel_ttl = 64;
+ tkey.remote_ipv4 = 0x0a020166; /* 10.2.1.102 */
+ bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), 0);
+ return bpf_redirect(*ifindex, 0);
+}
+
+SEC("l2_to_ip6tun_ingress_redirect")
+int _l2_to_ip6tun_ingress_redirect(struct __sk_buff *skb)
+{
+ struct bpf_tunnel_key tkey = {};
+ void *data = (void *)(long)skb->data;
+ struct eth_hdr *eth = data;
+ void *data_end = (void *)(long)skb->data_end;
+ int key = 0, *ifindex;
+
+ if (data + sizeof(*eth) > data_end)
+ return TC_ACT_OK;
+
+ ifindex = bpf_map_lookup_elem(&tun_iface, &key);
+ if (!ifindex)
+ return TC_ACT_OK;
+
+ if (eth->h_proto == htons(ETH_P_IP)) {
+ char fmt4[] = "e/ingress redirect daddr4:%x to ifindex:%d\n";
+ struct iphdr *iph = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*iph) > data_end)
+ return TC_ACT_OK;
+
+ if (!is_vip_addr(eth->h_proto, iph->daddr))
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt4, sizeof(fmt4), _htonl(iph->daddr),
+ *ifindex);
+ } else if (eth->h_proto == htons(ETH_P_IPV6)) {
+ char fmt6[] = "e/ingress redirect daddr6:%x to ifindex:%d\n";
+ struct ipv6hdr *ip6h = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
+ return TC_ACT_OK;
+
+ if (!is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0]))
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt6, sizeof(fmt6),
+ _htonl(ip6h->daddr.s6_addr32[0]), *ifindex);
+ } else {
+ return TC_ACT_OK;
+ }
+
+ tkey.tunnel_id = 10000;
+ tkey.tunnel_ttl = 64;
+ /* 2401:db02:0:0:0:0:0:66 */
+ tkey.remote_ipv6[0] = _htonl(0x2401db02);
+ tkey.remote_ipv6[1] = 0;
+ tkey.remote_ipv6[2] = 0;
+ tkey.remote_ipv6[3] = _htonl(0x00000066);
+ bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), BPF_F_TUNINFO_IPV6);
+ return bpf_redirect(*ifindex, 0);
+}
+
+SEC("drop_non_tun_vip")
+int _drop_non_tun_vip(struct __sk_buff *skb)
+{
+ struct bpf_tunnel_key tkey = {};
+ void *data = (void *)(long)skb->data;
+ struct eth_hdr *eth = data;
+ void *data_end = (void *)(long)skb->data_end;
+
+ if (data + sizeof(*eth) > data_end)
+ return TC_ACT_OK;
+
+ if (eth->h_proto == htons(ETH_P_IP)) {
+ struct iphdr *iph = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*iph) > data_end)
+ return TC_ACT_OK;
+
+ if (is_vip_addr(eth->h_proto, iph->daddr))
+ return TC_ACT_SHOT;
+ } else if (eth->h_proto == htons(ETH_P_IPV6)) {
+ struct ipv6hdr *ip6h = data + sizeof(*eth);
+
+ if (data + sizeof(*eth) + sizeof(*ip6h) > data_end)
+ return TC_ACT_OK;
+
+ if (is_vip_addr(eth->h_proto, ip6h->daddr.s6_addr32[0]))
+ return TC_ACT_SHOT;
+ }
+
+ return TC_ACT_OK;
+}
+
+char _license[] SEC("license") = "GPL";
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.