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bpf_host.c
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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2016-2020 Authors of Cilium */
#include <bpf/ctx/skb.h>
#include <bpf/api.h>
#include <node_config.h>
#include <ep_config.h>
#define IS_BPF_HOST 1
#define EVENT_SOURCE HOST_EP_ID
/* Host endpoint ID for the template bpf_host object file. Will be replaced
* at compile-time with the proper host endpoint ID.
*/
#define TEMPLATE_HOST_EP_ID 0xffff
/* These are configuration options which have a default value in their
* respective header files and must thus be defined beforehand:
*/
/* Pass unknown ICMPv6 NS to stack */
#define ACTION_UNKNOWN_ICMP6_NS CTX_ACT_OK
/* Include policy_can_access_ingress() */
#define REQUIRES_CAN_ACCESS
/* CB_PROXY_MAGIC overlaps with CB_ENCRYPT_MAGIC */
#define ENCRYPT_OR_PROXY_MAGIC 0
#ifdef POD_ENDPOINT
# undef ENABLE_HOST_FIREWALL
#endif
/* Controls the inclusion of the CILIUM_CALL_SEND_ICMP6_ECHO_REPLY section in
* the bpf_lxc object file.
*/
#define SKIP_ICMPV6_ECHO_HANDLING
#ifndef VLAN_FILTER
# define VLAN_FILTER(ifindex, vlan_id) return false;
#endif
#include "lib/common.h"
#include "lib/edt.h"
#include "lib/arp.h"
#include "lib/maps.h"
#include "lib/ipv6.h"
#include "lib/ipv4.h"
#include "lib/icmp6.h"
#include "lib/eth.h"
#include "lib/dbg.h"
#include "lib/proxy.h"
#include "lib/trace.h"
#include "lib/identity.h"
#include "lib/l3.h"
#include "lib/l4.h"
#include "lib/drop.h"
#include "lib/encap.h"
#include "lib/nat.h"
#include "lib/lb.h"
#include "lib/nodeport.h"
#include "lib/eps.h"
#include "lib/host_firewall.h"
#include "lib/overloadable.h"
#include "lib/encrypt.h"
static __always_inline bool allow_vlan(__u32 __maybe_unused ifindex, __u32 __maybe_unused vlan_id) {
VLAN_FILTER(ifindex, vlan_id);
}
#if defined(ENABLE_IPV4) || defined(ENABLE_IPV6)
static __always_inline int rewrite_dmac_to_host(struct __ctx_buff *ctx,
__u32 src_identity)
{
/* When attached to cilium_host, we rewrite the DMAC to the mac of
* cilium_host (peer) to ensure the packet is being considered to be
* addressed to the host (PACKET_HOST).
*/
union macaddr cilium_net_mac = CILIUM_NET_MAC;
/* Rewrite to destination MAC of cilium_net (remote peer) */
if (eth_store_daddr(ctx, (__u8 *) &cilium_net_mac.addr, 0) < 0)
return send_drop_notify_error(ctx, src_identity, DROP_WRITE_ERROR,
CTX_ACT_OK, METRIC_INGRESS);
return CTX_ACT_OK;
}
#define SECCTX_FROM_IPCACHE_OK 2
#ifndef SECCTX_FROM_IPCACHE
# define SECCTX_FROM_IPCACHE 0
#endif
static __always_inline bool identity_from_ipcache_ok(void)
{
return SECCTX_FROM_IPCACHE == SECCTX_FROM_IPCACHE_OK;
}
#endif
#ifdef ENABLE_IPV6
static __always_inline __u32
derive_src_id(const union v6addr *node_ip, struct ipv6hdr *ip6, __u32 *identity)
{
if (ipv6_match_prefix_64((union v6addr *) &ip6->saddr, node_ip)) {
/* Read initial 4 bytes of header and then extract flowlabel */
__u32 *tmp = (__u32 *) ip6;
*identity = bpf_ntohl(*tmp & IPV6_FLOWLABEL_MASK);
/* A remote node will map any HOST_ID source to be presented as
* REMOTE_NODE_ID, therefore any attempt to signal HOST_ID as
* source from a remote node can be dropped.
*/
if (*identity == HOST_ID)
return DROP_INVALID_IDENTITY;
}
return 0;
}
# ifdef ENABLE_HOST_FIREWALL
static __always_inline __u32
ipcache_lookup_srcid6(struct __ctx_buff *ctx)
{
struct remote_endpoint_info *info = NULL;
void *data, *data_end;
struct ipv6hdr *ip6;
__u32 srcid = 0;
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
info = lookup_ip6_remote_endpoint((union v6addr *) &ip6->saddr);
if (info != NULL)
srcid = info->sec_label;
cilium_dbg(ctx, info ? DBG_IP_ID_MAP_SUCCEED6 : DBG_IP_ID_MAP_FAILED6,
ip6->saddr.s6_addr32[3], srcid);
return srcid;
}
# endif /* ENABLE_HOST_FIREWALL */
static __always_inline __u32
resolve_srcid_ipv6(struct __ctx_buff *ctx, __u32 srcid_from_proxy,
const bool from_host)
{
__u32 src_id = WORLD_ID, srcid_from_ipcache = srcid_from_proxy;
struct remote_endpoint_info *info = NULL;
void *data, *data_end;
struct ipv6hdr *ip6;
union v6addr *src;
int ret;
if (!revalidate_data_maybe_pull(ctx, &data, &data_end, &ip6, !from_host))
return DROP_INVALID;
if (!from_host) {
union v6addr node_ip = {};
BPF_V6(node_ip, ROUTER_IP);
ret = derive_src_id(&node_ip, ip6, &src_id);
if (IS_ERR(ret))
return ret;
}
/* Packets from the proxy will already have a real identity. */
if (identity_is_reserved(srcid_from_ipcache)) {
src = (union v6addr *) &ip6->saddr;
info = lookup_ip6_remote_endpoint(src);
if (info != NULL && info->sec_label)
srcid_from_ipcache = info->sec_label;
cilium_dbg(ctx, info ? DBG_IP_ID_MAP_SUCCEED6 : DBG_IP_ID_MAP_FAILED6,
((__u32 *) src)[3], srcid_from_ipcache);
}
if (from_host)
src_id = srcid_from_ipcache;
else if (src_id == WORLD_ID &&
identity_from_ipcache_ok() &&
!identity_is_reserved(srcid_from_ipcache))
src_id = srcid_from_ipcache;
return src_id;
}
static __always_inline int
handle_ipv6(struct __ctx_buff *ctx, __u32 secctx, const bool from_host)
{
struct remote_endpoint_info *info = NULL;
void *data, *data_end;
struct ipv6hdr *ip6;
union v6addr *dst;
__u32 __maybe_unused monitor = 0;
__u32 __maybe_unused remote_id = WORLD_ID;
int ret, l3_off = ETH_HLEN, hdrlen;
bool skip_redirect = false;
struct endpoint_info *ep;
__u8 nexthdr;
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
nexthdr = ip6->nexthdr;
hdrlen = ipv6_hdrlen(ctx, ETH_HLEN, &nexthdr);
if (hdrlen < 0)
return hdrlen;
if (likely(nexthdr == IPPROTO_ICMPV6)) {
ret = icmp6_host_handle(ctx);
if (ret == SKIP_HOST_FIREWALL)
goto skip_host_firewall;
if (IS_ERR(ret))
return ret;
}
#ifdef ENABLE_NODEPORT
if (!from_host) {
if (ctx_get_xfer(ctx) != XFER_PKT_NO_SVC &&
!bpf_skip_nodeport(ctx)) {
ret = nodeport_lb6(ctx, secctx);
if (ret < 0)
return ret;
}
/* Verifier workaround: modified ctx access. */
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
}
#endif /* ENABLE_NODEPORT */
#if defined(NO_REDIRECT) && !defined(ENABLE_REDIRECT_FAST)
/* See IPv4 case for NO_REDIRECT/ENABLE_REDIRECT_FAST comments */
if (!from_host)
skip_redirect = true;
#endif /* NO_REDIRECT && !ENABLE_REDIRECT_FAST */
#ifdef ENABLE_HOST_FIREWALL
if (from_host) {
ret = ipv6_host_policy_egress(ctx, secctx, &monitor);
if (IS_ERR(ret))
return ret;
} else if (!ctx_skip_host_fw(ctx)) {
ret = ipv6_host_policy_ingress(ctx, &remote_id);
if (IS_ERR(ret))
return ret;
}
#endif /* ENABLE_HOST_FIREWALL */
if (skip_redirect)
return CTX_ACT_OK;
skip_host_firewall:
if (from_host) {
/* If we are attached to cilium_host at egress, this will
* rewrite the destination MAC address to the MAC of cilium_net.
*/
ret = rewrite_dmac_to_host(ctx, secctx);
/* DIRECT PACKET READ INVALID */
if (IS_ERR(ret))
return ret;
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
}
/* Lookup IPv4 address in list of local endpoints */
ep = lookup_ip6_endpoint(ip6);
if (ep) {
/* Let through packets to the node-ip so they are
* processed by the local ip stack.
*/
if (ep->flags & ENDPOINT_F_HOST)
return CTX_ACT_OK;
return ipv6_local_delivery(ctx, l3_off, secctx, ep,
METRIC_INGRESS, from_host);
}
/* Below remainder is only relevant when traffic is pushed via cilium_host.
* For traffic coming from external, we're done here.
*/
if (!from_host)
return CTX_ACT_OK;
#ifdef TUNNEL_MODE
dst = (union v6addr *) &ip6->daddr;
info = ipcache_lookup6(&IPCACHE_MAP, dst, V6_CACHE_KEY_LEN);
if (info != NULL && info->tunnel_endpoint != 0) {
ret = encap_and_redirect_with_nodeid(ctx, info->tunnel_endpoint,
info->key,
secctx, TRACE_PAYLOAD_LEN);
/* If IPSEC is needed recirc through ingress to use xfrm stack
* and then result will routed back through bpf_netdev on egress
* but with encrypt marks.
*/
if (ret == IPSEC_ENDPOINT)
return CTX_ACT_OK;
else
return ret;
} else {
struct endpoint_key key = {};
/* IPv6 lookup key: daddr/96 */
dst = (union v6addr *) &ip6->daddr;
key.ip6.p1 = dst->p1;
key.ip6.p2 = dst->p2;
key.ip6.p3 = dst->p3;
key.ip6.p4 = 0;
key.family = ENDPOINT_KEY_IPV6;
ret = encap_and_redirect_netdev(ctx, &key, secctx, TRACE_PAYLOAD_LEN);
if (ret == IPSEC_ENDPOINT)
return CTX_ACT_OK;
else if (ret != DROP_NO_TUNNEL_ENDPOINT)
return ret;
}
#endif
dst = (union v6addr *) &ip6->daddr;
info = ipcache_lookup6(&IPCACHE_MAP, dst, V6_CACHE_KEY_LEN);
if (info == NULL || info->sec_label == WORLD_ID) {
/* See IPv4 comment. */
return DROP_UNROUTABLE;
}
#ifdef ENABLE_IPSEC
if (info && info->key && info->tunnel_endpoint) {
__u8 key = get_min_encrypt_key(info->key);
set_encrypt_key_meta(ctx, key);
#ifdef IP_POOLS
set_encrypt_dip(ctx, info->tunnel_endpoint);
#else
set_identity_meta(ctx, secctx);
#endif
}
#endif
return CTX_ACT_OK;
}
static __always_inline int
tail_handle_ipv6(struct __ctx_buff *ctx, const bool from_host)
{
__u32 proxy_identity = ctx_load_meta(ctx, CB_SRC_IDENTITY);
int ret;
ctx_store_meta(ctx, CB_SRC_IDENTITY, 0);
ret = handle_ipv6(ctx, proxy_identity, from_host);
if (IS_ERR(ret))
return send_drop_notify_error(ctx, proxy_identity, ret,
CTX_ACT_DROP, METRIC_INGRESS);
return ret;
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV6_FROM_HOST)
int tail_handle_ipv6_from_host(struct __ctx_buff *ctx __maybe_unused)
{
return tail_handle_ipv6(ctx, true);
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV6_FROM_LXC)
int tail_handle_ipv6_from_netdev(struct __ctx_buff *ctx)
{
return tail_handle_ipv6(ctx, false);
}
# ifdef ENABLE_HOST_FIREWALL
static __always_inline int
handle_to_netdev_ipv6(struct __ctx_buff *ctx, __u32 *monitor)
{
void *data, *data_end;
struct ipv6hdr *ip6;
int hdrlen, ret;
__u32 src_id = 0;
__u8 nexthdr;
if (!revalidate_data_pull(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
nexthdr = ip6->nexthdr;
hdrlen = ipv6_hdrlen(ctx, ETH_HLEN, &nexthdr);
if (hdrlen < 0)
return hdrlen;
if (likely(nexthdr == IPPROTO_ICMPV6)) {
ret = icmp6_host_handle(ctx);
if (ret == SKIP_HOST_FIREWALL)
return CTX_ACT_OK;
if (IS_ERR(ret))
return ret;
}
/* to-netdev is attached to the egress path of the native device. */
src_id = ipcache_lookup_srcid6(ctx);
return ipv6_host_policy_egress(ctx, src_id, monitor);
}
#endif /* ENABLE_HOST_FIREWALL */
#endif /* ENABLE_IPV6 */
#ifdef ENABLE_IPV4
static __always_inline __u32
resolve_srcid_ipv4(struct __ctx_buff *ctx, __u32 srcid_from_proxy,
__u32 *sec_label, const bool from_host)
{
__u32 src_id = WORLD_ID, srcid_from_ipcache = srcid_from_proxy;
struct remote_endpoint_info *info = NULL;
void *data, *data_end;
struct iphdr *ip4;
/* This is the first time revalidate_data() is going to be called in
* the "to-netdev" path. Make sure that we don't legitimately drop
* the packet if the skb arrived with the header not being not in the
* linear data.
*/
if (!revalidate_data_maybe_pull(ctx, &data, &data_end, &ip4, !from_host))
return DROP_INVALID;
/* Packets from the proxy will already have a real identity. */
if (identity_is_reserved(srcid_from_ipcache)) {
info = lookup_ip4_remote_endpoint(ip4->saddr);
if (info != NULL) {
*sec_label = info->sec_label;
if (*sec_label) {
/* When SNAT is enabled on traffic ingressing
* into Cilium, all traffic from the world will
* have a source IP of the host. It will only
* actually be from the host if "srcid_from_proxy"
* (passed into this function) reports the src as
* the host. So we can ignore the ipcache if it
* reports the source as HOST_ID.
*/
#ifndef ENABLE_EXTRA_HOST_DEV
if (*sec_label != HOST_ID)
srcid_from_ipcache = *sec_label;
#else
if ((*sec_label != HOST_ID &&
!from_host) || from_host)
srcid_from_ipcache = *sec_label;
#endif /* ENABLE_EXTRA_HOST_DEV */
}
}
cilium_dbg(ctx, info ? DBG_IP_ID_MAP_SUCCEED4 : DBG_IP_ID_MAP_FAILED4,
ip4->saddr, srcid_from_ipcache);
}
if (from_host)
src_id = srcid_from_ipcache;
/* If we could not derive the secctx from the packet itself but
* from the ipcache instead, then use the ipcache identity.
*/
else if (identity_from_ipcache_ok() &&
!identity_is_reserved(srcid_from_ipcache))
src_id = srcid_from_ipcache;
return src_id;
}
static __always_inline int
handle_ipv4(struct __ctx_buff *ctx, __u32 secctx,
__u32 ipcache_srcid __maybe_unused, const bool from_host)
{
struct remote_endpoint_info *info = NULL;
__u32 __maybe_unused remote_id = 0;
__u32 __maybe_unused monitor = 0;
struct ipv4_ct_tuple tuple = {};
bool skip_redirect = false;
struct endpoint_info *ep;
void *data, *data_end;
struct iphdr *ip4;
int ret;
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
/* If IPv4 fragmentation is disabled
* AND a IPv4 fragmented packet is received,
* then drop the packet.
*/
#ifndef ENABLE_IPV4_FRAGMENTS
if (ipv4_is_fragment(ip4))
return DROP_FRAG_NOSUPPORT;
#endif
#ifdef ENABLE_NODEPORT
if (!from_host) {
if (ctx_get_xfer(ctx) != XFER_PKT_NO_SVC &&
!bpf_skip_nodeport(ctx)) {
ret = nodeport_lb4(ctx, secctx);
if (ret < 0)
return ret;
}
/* Verifier workaround: modified ctx access. */
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
}
#endif /* ENABLE_NODEPORT */
#if defined(NO_REDIRECT) && !defined(ENABLE_REDIRECT_FAST)
/* Without bpf_redirect_neigh() helper, we cannot redirect a
* packet to a local endpoint in the direct routing mode, as
* the redirect bypasses nf_conntrack table. This makes a
* second reply from the endpoint to be MASQUERADEd or to be
* DROP-ed by k8s's "--ctstate INVALID -j DROP" depending via
* which interface it was inputed. With bpf_redirect_neigh()
* we bypass request and reply path in the host namespace and
* do not run into this issue.
*/
if (!from_host)
skip_redirect = true;
#endif /* NO_REDIRECT && !ENABLE_REDIRECT_FAST */
#ifdef ENABLE_HOST_FIREWALL
if (from_host) {
/* We're on the egress path of cilium_host. */
ret = ipv4_host_policy_egress(ctx, secctx, ipcache_srcid, &monitor);
if (IS_ERR(ret))
return ret;
} else if (!ctx_skip_host_fw(ctx)) {
/* We're on the ingress path of the native device. */
ret = ipv4_host_policy_ingress(ctx, &remote_id);
if (IS_ERR(ret))
return ret;
}
#endif /* ENABLE_HOST_FIREWALL */
if (skip_redirect)
return CTX_ACT_OK;
tuple.nexthdr = ip4->protocol;
if (from_host) {
/* If we are attached to cilium_host at egress, this will
* rewrite the destination MAC address to the MAC of cilium_net.
*/
ret = rewrite_dmac_to_host(ctx, secctx);
/* DIRECT PACKET READ INVALID */
if (IS_ERR(ret))
return ret;
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
}
/* Lookup IPv4 address in list of local endpoints and host IPs */
ep = lookup_ip4_endpoint(ip4);
if (ep) {
/* Let through packets to the node-ip so they are processed by
* the local ip stack.
*/
if (ep->flags & ENDPOINT_F_HOST)
return CTX_ACT_OK;
return ipv4_local_delivery(ctx, ETH_HLEN, secctx, ip4, ep,
METRIC_INGRESS, from_host);
}
/* Below remainder is only relevant when traffic is pushed via cilium_host.
* For traffic coming from external, we're done here.
*/
if (!from_host)
return CTX_ACT_OK;
#ifdef TUNNEL_MODE
info = ipcache_lookup4(&IPCACHE_MAP, ip4->daddr, V4_CACHE_KEY_LEN);
if (info != NULL && info->tunnel_endpoint != 0) {
ret = encap_and_redirect_with_nodeid(ctx, info->tunnel_endpoint,
info->key, secctx,
TRACE_PAYLOAD_LEN);
if (ret == IPSEC_ENDPOINT)
return CTX_ACT_OK;
else
return ret;
} else {
/* IPv4 lookup key: daddr & IPV4_MASK */
struct endpoint_key key = {};
key.ip4 = ip4->daddr & IPV4_MASK;
key.family = ENDPOINT_KEY_IPV4;
cilium_dbg(ctx, DBG_NETDEV_ENCAP4, key.ip4, secctx);
ret = encap_and_redirect_netdev(ctx, &key, secctx, TRACE_PAYLOAD_LEN);
if (ret == IPSEC_ENDPOINT)
return CTX_ACT_OK;
else if (ret != DROP_NO_TUNNEL_ENDPOINT)
return ret;
}
#endif
info = ipcache_lookup4(&IPCACHE_MAP, ip4->daddr, V4_CACHE_KEY_LEN);
if (info == NULL || info->sec_label == WORLD_ID) {
/* We have received a packet for which no ipcache entry exists,
* we do not know what to do with this packet, drop it.
*
* The info == NULL test is soley to satisfy verifier requirements
* as in Cilium case we'll always hit the 0.0.0.0/32 catch-all
* entry. Therefore we need to test for WORLD_ID. It is clearly
* wrong to route a ctx to cilium_host for which we don't know
* anything about it as otherwise we'll run into a routing loop.
*/
return DROP_UNROUTABLE;
}
#ifdef ENABLE_IPSEC
if (info && info->key && info->tunnel_endpoint) {
__u8 key = get_min_encrypt_key(info->key);
set_encrypt_key_meta(ctx, key);
#ifdef IP_POOLS
set_encrypt_dip(ctx, info->tunnel_endpoint);
#else
set_identity_meta(ctx, secctx);
#endif
}
#endif
return CTX_ACT_OK;
}
static __always_inline int
tail_handle_ipv4(struct __ctx_buff *ctx, __u32 ipcache_srcid, const bool from_host)
{
__u32 proxy_identity = ctx_load_meta(ctx, CB_SRC_IDENTITY);
int ret;
ctx_store_meta(ctx, CB_SRC_IDENTITY, 0);
ret = handle_ipv4(ctx, proxy_identity, ipcache_srcid, from_host);
if (IS_ERR(ret))
return send_drop_notify_error(ctx, proxy_identity,
ret, CTX_ACT_DROP, METRIC_INGRESS);
return ret;
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV4_FROM_HOST)
int tail_handle_ipv4_from_host(struct __ctx_buff *ctx)
{
__u32 ipcache_srcid = 0;
#if defined(ENABLE_HOST_FIREWALL) && !defined(ENABLE_MASQUERADE)
ipcache_srcid = ctx_load_meta(ctx, CB_IPCACHE_SRC_LABEL);
ctx_store_meta(ctx, CB_IPCACHE_SRC_LABEL, 0);
#endif
return tail_handle_ipv4(ctx, ipcache_srcid, true);
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV4_FROM_LXC)
int tail_handle_ipv4_from_netdev(struct __ctx_buff *ctx)
{
return tail_handle_ipv4(ctx, 0, false);
}
#ifdef ENABLE_HOST_FIREWALL
static __always_inline int
handle_to_netdev_ipv4(struct __ctx_buff *ctx, __u32 *monitor)
{
void *data, *data_end;
struct iphdr *ip4;
__u32 src_id = 0, ipcache_srcid = 0;
if ((ctx->mark & MARK_MAGIC_HOST_MASK) == MARK_MAGIC_HOST)
src_id = HOST_ID;
src_id = resolve_srcid_ipv4(ctx, src_id, &ipcache_srcid, true);
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
/* We need to pass the srcid from ipcache to host firewall. See
* comment in ipv4_host_policy_egress() for details.
*/
return ipv4_host_policy_egress(ctx, src_id, ipcache_srcid, monitor);
}
#endif /* ENABLE_HOST_FIREWALL */
#endif /* ENABLE_IPV4 */
#ifdef ENABLE_IPSEC
#ifndef TUNNEL_MODE
static __always_inline int
do_netdev_encrypt_pools(struct __ctx_buff *ctx __maybe_unused)
{
int ret = 0;
#ifdef IP_POOLS
__u32 tunnel_endpoint = 0;
void *data, *data_end;
__u32 tunnel_source = IPV4_ENCRYPT_IFACE;
struct iphdr *iphdr;
__be32 sum;
tunnel_endpoint = ctx_load_meta(ctx, 4);
ctx->mark = 0;
if (!revalidate_data(ctx, &data, &data_end, &iphdr)) {
ret = DROP_INVALID;
goto drop_err;
}
/* When IP_POOLS is enabled ip addresses are not
* assigned on a per node basis so lacking node
* affinity we can not use IP address to assign the
* destination IP. Instead rewrite it here from cb[].
*/
sum = csum_diff(&iphdr->daddr, 4, &tunnel_endpoint, 4, 0);
if (ctx_store_bytes(ctx, ETH_HLEN + offsetof(struct iphdr, daddr),
&tunnel_endpoint, 4, 0) < 0) {
ret = DROP_WRITE_ERROR;
goto drop_err;
}
if (l3_csum_replace(ctx, ETH_HLEN + offsetof(struct iphdr, check),
0, sum, 0) < 0) {
ret = DROP_CSUM_L3;
goto drop_err;
}
if (!revalidate_data(ctx, &data, &data_end, &iphdr)) {
ret = DROP_INVALID;
goto drop_err;
}
sum = csum_diff(&iphdr->saddr, 4, &tunnel_source, 4, 0);
if (ctx_store_bytes(ctx, ETH_HLEN + offsetof(struct iphdr, saddr),
&tunnel_source, 4, 0) < 0) {
ret = DROP_WRITE_ERROR;
goto drop_err;
}
if (l3_csum_replace(ctx, ETH_HLEN + offsetof(struct iphdr, check),
0, sum, 0) < 0) {
ret = DROP_CSUM_L3;
goto drop_err;
}
drop_err:
#endif /* IP_POOLS */
return ret;
}
static __always_inline int
do_netdev_encrypt_fib(struct __ctx_buff *ctx __maybe_unused,
__u16 proto __maybe_unused,
int *encrypt_iface __maybe_unused)
{
int ret = 0;
/* Only do FIB lookup if both the BPF helper is supported and we know
* the egress ineterface. If we don't have an egress interface,
* typically in an environment with many egress devs than we have
* to let the stack decide how to egress the packet. EKS is the
* example of an environment with multiple egress interfaces.
*/
#if defined(BPF_HAVE_FIB_LOOKUP) && defined(ENCRYPT_IFACE)
struct bpf_fib_lookup fib_params = {};
void *data, *data_end;
int err;
if (proto == bpf_htons(ETH_P_IP)) {
struct iphdr *ip4;
if (!revalidate_data(ctx, &data, &data_end, &ip4)) {
ret = DROP_INVALID;
goto drop_err_fib;
}
fib_params.family = AF_INET;
fib_params.ipv4_src = ip4->saddr;
fib_params.ipv4_dst = ip4->daddr;
} else {
struct ipv6hdr *ip6;
if (!revalidate_data(ctx, &data, &data_end, &ip6)) {
ret = DROP_INVALID;
goto drop_err_fib;
}
fib_params.family = AF_INET6;
ipv6_addr_copy((union v6addr *) &fib_params.ipv6_src, (union v6addr *) &ip6->saddr);
ipv6_addr_copy((union v6addr *) &fib_params.ipv6_dst, (union v6addr *) &ip6->daddr);
}
fib_params.ifindex = *encrypt_iface;
err = fib_lookup(ctx, &fib_params, sizeof(fib_params),
BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT);
if (err != 0) {
ret = DROP_NO_FIB;
goto drop_err_fib;
}
if (eth_store_daddr(ctx, fib_params.dmac, 0) < 0) {
ret = DROP_WRITE_ERROR;
goto drop_err_fib;
}
if (eth_store_saddr(ctx, fib_params.smac, 0) < 0) {
ret = DROP_WRITE_ERROR;
goto drop_err_fib;
}
*encrypt_iface = fib_params.ifindex;
drop_err_fib:
#endif /* BPF_HAVE_FIB_LOOKUP */
return ret;
}
static __always_inline int do_netdev_encrypt(struct __ctx_buff *ctx, __u16 proto)
{
int encrypt_iface = 0;
int ret = 0;
#if defined(ENCRYPT_IFACE) && defined(BPF_HAVE_FIB_LOOKUP)
encrypt_iface = ENCRYPT_IFACE;
#endif
ret = do_netdev_encrypt_pools(ctx);
if (ret)
return send_drop_notify_error(ctx, 0, ret, CTX_ACT_DROP, METRIC_INGRESS);
ret = do_netdev_encrypt_fib(ctx, proto, &encrypt_iface);
if (ret)
return send_drop_notify_error(ctx, 0, ret, CTX_ACT_DROP, METRIC_INGRESS);
bpf_clear_meta(ctx);
#ifdef BPF_HAVE_FIB_LOOKUP
/* Redirect only works if we have a fib lookup to set the MAC
* addresses. Otherwise let the stack do the routing and fib
* Note, without FIB lookup implemented the packet may have
* incorrect dmac leaving bpf_host so will need to mark as
* PACKET_HOST or otherwise fixup MAC addresses.
*/
if (encrypt_iface)
return redirect(encrypt_iface, 0);
#endif
return CTX_ACT_OK;
}
#else /* TUNNEL_MODE */
static __always_inline int do_netdev_encrypt_encap(struct __ctx_buff *ctx)
{
__u32 seclabel, tunnel_endpoint = 0;
seclabel = get_identity(ctx);
tunnel_endpoint = ctx_load_meta(ctx, 4);
ctx->mark = 0;
bpf_clear_meta(ctx);
return __encap_and_redirect_with_nodeid(ctx, tunnel_endpoint, seclabel, TRACE_PAYLOAD_LEN);
}
static __always_inline int do_netdev_encrypt(struct __ctx_buff *ctx, __u16 proto __maybe_unused)
{
return do_netdev_encrypt_encap(ctx);
}
#endif /* TUNNEL_MODE */
#endif /* ENABLE_IPSEC */
static __always_inline int
do_netdev(struct __ctx_buff *ctx, __u16 proto, const bool from_host)
{
__u32 __maybe_unused identity = 0;
__u32 __maybe_unused ipcache_srcid = 0;
int ret;
#ifdef ENABLE_IPSEC
if (from_host) {
__u32 magic = ctx->mark & MARK_MAGIC_HOST_MASK;
if (magic == MARK_MAGIC_ENCRYPT)
return do_netdev_encrypt(ctx, proto);
} else {
int done = do_decrypt(ctx, proto);
if (!done)
return CTX_ACT_OK;
}
#endif
bpf_clear_meta(ctx);
if (from_host) {
int trace = TRACE_FROM_HOST;
bool from_proxy;
from_proxy = inherit_identity_from_host(ctx, &identity);
if (from_proxy)
trace = TRACE_FROM_PROXY;
send_trace_notify(ctx, trace, identity, 0, 0,
ctx->ingress_ifindex, 0, TRACE_PAYLOAD_LEN);
} else {
bpf_skip_nodeport_clear(ctx);
send_trace_notify(ctx, TRACE_FROM_NETWORK, 0, 0, 0,
ctx->ingress_ifindex, 0, TRACE_PAYLOAD_LEN);
}
switch (proto) {
# if defined ENABLE_ARP_PASSTHROUGH || defined ENABLE_ARP_RESPONDER
case bpf_htons(ETH_P_ARP):
ret = CTX_ACT_OK;
break;
# endif
#ifdef ENABLE_IPV6
case bpf_htons(ETH_P_IPV6):
identity = resolve_srcid_ipv6(ctx, identity, from_host);
ctx_store_meta(ctx, CB_SRC_IDENTITY, identity);
if (from_host)
ep_tail_call(ctx, CILIUM_CALL_IPV6_FROM_HOST);
else
ep_tail_call(ctx, CILIUM_CALL_IPV6_FROM_LXC);
/* See comment below for IPv4. */
return send_drop_notify_error(ctx, identity, DROP_MISSED_TAIL_CALL,
CTX_ACT_OK, METRIC_INGRESS);
#endif
#ifdef ENABLE_IPV4
case bpf_htons(ETH_P_IP):
identity = resolve_srcid_ipv4(ctx, identity, &ipcache_srcid,
from_host);
ctx_store_meta(ctx, CB_SRC_IDENTITY, identity);
if (from_host) {
# if defined(ENABLE_HOST_FIREWALL) && !defined(ENABLE_MASQUERADE)
/* If we don't rely on BPF-based masquerading, we need
* to pass the srcid from ipcache to host firewall. See
* comment in ipv4_host_policy_egress() for details.
*/
ctx_store_meta(ctx, CB_IPCACHE_SRC_LABEL, ipcache_srcid);
# endif
ep_tail_call(ctx, CILIUM_CALL_IPV4_FROM_HOST);
} else {
ep_tail_call(ctx, CILIUM_CALL_IPV4_FROM_LXC);
}
/* We are not returning an error here to always allow traffic to
* the stack in case maps have become unavailable.
*
* Note: Since drop notification requires a tail call as well,
* this notification is unlikely to succeed.
*/
return send_drop_notify_error(ctx, identity, DROP_MISSED_TAIL_CALL,
CTX_ACT_OK, METRIC_INGRESS);
#endif
default:
#ifdef ENABLE_HOST_FIREWALL
ret = send_drop_notify_error(ctx, identity, DROP_UNKNOWN_L3,
CTX_ACT_DROP, METRIC_INGRESS);
#else
/* Pass unknown traffic to the stack */
ret = CTX_ACT_OK;
#endif /* ENABLE_HOST_FIREWALL */
}
return ret;
}
/**
* handle_netdev
* @ctx The packet context for this program
* @from_host True if the packet is from the local host
*
* Handle netdev traffic coming towards the Cilium-managed network.
*/
static __always_inline int
handle_netdev(struct __ctx_buff *ctx, const bool from_host)
{
__u16 proto;
if (!validate_ethertype(ctx, &proto)) {
#ifdef ENABLE_HOST_FIREWALL
int ret = DROP_UNSUPPORTED_L2;
return send_drop_notify(ctx, SECLABEL, WORLD_ID, 0, ret,
CTX_ACT_DROP, METRIC_EGRESS);
#else
send_trace_notify(ctx, TRACE_TO_STACK, HOST_ID, 0, 0, 0,
REASON_FORWARDED, 0);
/* Pass unknown traffic to the stack */
return CTX_ACT_OK;
#endif /* ENABLE_HOST_FIREWALL */
}
return do_netdev(ctx, proto, from_host);
}
/*
* from-netdev is attached as a tc ingress filter to one or more physical devices
* managed by Cilium (e.g., eth0). This program is only attached when:
* - the host firewall is enabled, or
* - BPF NodePort is enabled
*/
__section("from-netdev")
int from_netdev(struct __ctx_buff *ctx)
{
__u32 __maybe_unused vlan_id;
/* Filter allowed vlan id's and pass them back to kernel.
*/
if (ctx->vlan_present) {
vlan_id = ctx->vlan_tci & 0xfff;
if (vlan_id) {
if (allow_vlan(ctx->ifindex, vlan_id))
return CTX_ACT_OK;
else
return send_drop_notify_error(ctx, 0, DROP_VLAN_FILTERED,
CTX_ACT_DROP, METRIC_INGRESS);
}
}
return handle_netdev(ctx, false);
}
/*
* from-host is attached as a tc egress filter to the node's 'cilium_host'
* interface if present.
*/