bpf_overlay.c
/*
* Copyright (C) 2016-2017 Authors of Cilium
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <node_config.h>
#include <netdev_config.h>
#include <bpf/api.h>
#include <stdint.h>
#include <stdio.h>
#include "lib/utils.h"
#include "lib/common.h"
#include "lib/maps.h"
#include "lib/ipv6.h"
#include "lib/eth.h"
#include "lib/dbg.h"
#include "lib/trace.h"
#include "lib/l3.h"
#include "lib/drop.h"
#include "lib/policy.h"
static inline int handle_ipv6(struct __sk_buff *skb)
{
void *data_end, *data;
struct ipv6hdr *ip6;
struct bpf_tunnel_key key = {};
struct endpoint_info *ep;
int l4_off, l3_off = ETH_HLEN;
if (!revalidate_data(skb, &data, &data_end, &ip6))
return DROP_INVALID;
if (unlikely(skb_get_tunnel_key(skb, &key, sizeof(key), 0) < 0))
return DROP_NO_TUNNEL_KEY;
cilium_dbg(skb, DBG_DECAP, key.tunnel_id, key.tunnel_label);
/* Lookup IPv6 address in list of local endpoints */
if ((ep = lookup_ip6_endpoint(ip6)) != NULL) {
/* Let through packets to the node-ip so they are
* processed by the local ip stack */
if (ep->flags & ENDPOINT_F_HOST)
goto to_host;
__u8 nexthdr = ip6->nexthdr;
l4_off = l3_off + ipv6_hdrlen(skb, l3_off, &nexthdr);
return ipv6_local_delivery(skb, l3_off, l4_off, key.tunnel_id, ip6, nexthdr, ep, METRIC_INGRESS);
} else {
return DROP_NON_LOCAL;
}
to_host:
#ifdef HOST_IFINDEX
if (1) {
union macaddr host_mac = HOST_IFINDEX_MAC;
union macaddr router_mac = NODE_MAC;
int ret;
cilium_dbg(skb, DBG_TO_HOST, is_policy_skip(skb), 0);
ret = ipv6_l3(skb, ETH_HLEN, (__u8 *) &router_mac.addr, (__u8 *) &host_mac.addr, METRIC_INGRESS);
if (ret != TC_ACT_OK)
return ret;
cilium_dbg_capture(skb, DBG_CAPTURE_DELIVERY, HOST_IFINDEX);
return redirect(HOST_IFINDEX, 0);
}
#else
return TC_ACT_OK;
#endif
}
#ifdef ENABLE_IPV4
static inline int handle_ipv4(struct __sk_buff *skb)
{
void *data_end, *data;
struct iphdr *ip4;
struct endpoint_info *ep;
struct bpf_tunnel_key key = {};
int l4_off;
if (!revalidate_data(skb, &data, &data_end, &ip4))
return DROP_INVALID;
if (unlikely(skb_get_tunnel_key(skb, &key, sizeof(key), 0) < 0))
return DROP_NO_TUNNEL_KEY;
l4_off = ETH_HLEN + ipv4_hdrlen(ip4);
/* Lookup IPv4 address in list of local endpoints */
if ((ep = lookup_ip4_endpoint(ip4)) != NULL) {
/* Let through packets to the node-ip so they are
* processed by the local ip stack */
if (ep->flags & ENDPOINT_F_HOST)
goto to_host;
return ipv4_local_delivery(skb, ETH_HLEN, l4_off, key.tunnel_id, ip4, ep, METRIC_INGRESS);
} else {
return DROP_NON_LOCAL;
}
to_host:
#ifdef HOST_IFINDEX
if (1) {
union macaddr host_mac = HOST_IFINDEX_MAC;
union macaddr router_mac = NODE_MAC;
int ret;
cilium_dbg(skb, DBG_TO_HOST, is_policy_skip(skb), 0);
ret = ipv4_l3(skb, ETH_HLEN, (__u8 *) &router_mac.addr, (__u8 *) &host_mac.addr, ip4);
if (ret != TC_ACT_OK)
return ret;
cilium_dbg_capture(skb, DBG_CAPTURE_DELIVERY, HOST_IFINDEX);
return redirect(HOST_IFINDEX, 0);
}
#else
return TC_ACT_OK;
#endif
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV4) int tail_handle_ipv4(struct __sk_buff *skb)
{
int ret = handle_ipv4(skb);
if (IS_ERR(ret))
return send_drop_notify_error(skb, ret, TC_ACT_SHOT, METRIC_INGRESS);
return ret;
}
#endif
__section("from-overlay")
int from_overlay(struct __sk_buff *skb)
{
int ret;
bpf_clear_cb(skb);
send_trace_notify(skb, TRACE_FROM_OVERLAY, 0, 0, 0, skb->ingress_ifindex, 0);
switch (skb->protocol) {
case bpf_htons(ETH_P_IPV6):
/* This is considered the fast path, no tail call */
ret = handle_ipv6(skb);
break;
case bpf_htons(ETH_P_IP):
#ifdef ENABLE_IPV4
ep_tail_call(skb, CILIUM_CALL_IPV4);
ret = DROP_MISSED_TAIL_CALL;
#else
ret = DROP_UNKNOWN_L3;
#endif
break;
default:
/* Pass unknown traffic to the stack */
ret = TC_ACT_OK;
}
if (IS_ERR(ret))
return send_drop_notify_error(skb, ret, TC_ACT_SHOT, METRIC_INGRESS);
else
return ret;
}
BPF_LICENSE("GPL");