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bpf_host.c
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bpf_host.c
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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright 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
#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/srv6.h"
#include "lib/overloadable.h"
#include "lib/encrypt.h"
#include "lib/wireguard.h"
/* Bit 0 is skipped for robustness, as it's used in some places to indicate from_host itself. */
#define FROM_HOST_FLAG_NEED_HOSTFW (1 << 1)
#define FROM_HOST_FLAG_HOST_ID (1 << 2)
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_sec_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_sec_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
resolve_srcid_ipv6(struct __ctx_buff *ctx, struct ipv6hdr *ip6,
__u32 srcid_from_ipcache, __u32 *sec_identity,
const bool from_host)
{
__u32 src_id = WORLD_ID;
struct remote_endpoint_info *info = NULL;
union v6addr *src;
/* 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, 0);
if (info) {
*sec_identity = info->sec_identity;
if (*sec_identity) {
/* 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.
*/
if (*sec_identity != HOST_ID)
srcid_from_ipcache = *sec_identity;
}
}
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 (identity_from_ipcache_ok())
src_id = srcid_from_ipcache;
return src_id;
}
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, __u32);
__type(value, struct ct_buffer6);
__uint(max_entries, 1);
} CT_TAIL_CALL_BUFFER6 __section_maps_btf;
static __always_inline int
handle_ipv6(struct __ctx_buff *ctx, __u32 secctx __maybe_unused,
__u32 ipcache_srcid __maybe_unused,
const bool from_host __maybe_unused,
__s8 *ext_err __maybe_unused)
{
#ifdef ENABLE_HOST_FIREWALL
struct ct_buffer6 ct_buffer = {};
bool need_hostfw = false;
bool is_host_id = false;
#endif /* ENABLE_HOST_FIREWALL */
void *data, *data_end;
struct ipv6hdr *ip6;
int __maybe_unused ret;
int hdrlen;
__u8 nexthdr;
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
nexthdr = ip6->nexthdr;
hdrlen = ipv6_hdrlen(ctx, &nexthdr);
if (hdrlen < 0)
return hdrlen;
#ifdef ENABLE_HOST_FIREWALL
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;
}
#endif /* ENABLE_HOST_FIREWALL */
#ifdef ENABLE_NODEPORT
if (!from_host) {
if (!ctx_skip_nodeport(ctx)) {
bool is_dsr = false;
ret = nodeport_lb6(ctx, ip6, secctx, ext_err, &is_dsr);
/* nodeport_lb6() returns with TC_ACT_REDIRECT for
* traffic to L7 LB. Policy enforcement needs to take
* place after L7 LB has processed the packet, so we
* return to stack immediately here with
* TC_ACT_REDIRECT.
*/
if (ret < 0 || ret == TC_ACT_REDIRECT)
return ret;
}
}
#endif /* ENABLE_NODEPORT */
#ifdef ENABLE_HOST_FIREWALL
if (from_host) {
if (ipv6_host_policy_egress_lookup(ctx, secctx, ipcache_srcid, ip6, &ct_buffer)) {
if (unlikely(ct_buffer.ret < 0))
return ct_buffer.ret;
need_hostfw = true;
is_host_id = secctx == HOST_ID;
}
} else if (!ctx_skip_host_fw(ctx)) {
/* Verifier workaround: R5 invalid mem access 'scalar'. */
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
if (ipv6_host_policy_ingress_lookup(ctx, ip6, &ct_buffer)) {
if (unlikely(ct_buffer.ret < 0))
return ct_buffer.ret;
need_hostfw = true;
}
}
if (need_hostfw) {
__u32 zero = 0;
if (map_update_elem(&CT_TAIL_CALL_BUFFER6, &zero, &ct_buffer, 0) < 0)
return DROP_INVALID_TC_BUFFER;
}
skip_host_firewall:
ctx_store_meta(ctx, CB_FROM_HOST,
(need_hostfw ? FROM_HOST_FLAG_NEED_HOSTFW : 0) |
(is_host_id ? FROM_HOST_FLAG_HOST_ID : 0));
#endif /* ENABLE_HOST_FIREWALL */
return CTX_ACT_OK;
}
static __always_inline int
handle_ipv6_cont(struct __ctx_buff *ctx, __u32 secctx, const bool from_host,
__s8 *ext_err __maybe_unused)
{
struct trace_ctx __maybe_unused trace = {
.reason = TRACE_REASON_UNKNOWN,
.monitor = TRACE_PAYLOAD_LEN,
};
__u32 __maybe_unused from_host_raw;
void *data, *data_end;
struct ipv6hdr *ip6;
union v6addr *dst;
int l3_off = ETH_HLEN;
struct remote_endpoint_info *info = NULL;
struct endpoint_info *ep;
int ret;
__u8 encrypt_key __maybe_unused = 0;
bool from_ingress_proxy = tc_index_from_ingress_proxy(ctx);
if (!revalidate_data(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
#ifdef ENABLE_HOST_FIREWALL
from_host_raw = ctx_load_meta(ctx, CB_FROM_HOST);
ctx_store_meta(ctx, CB_FROM_HOST, 0);
if (from_host_raw & FROM_HOST_FLAG_NEED_HOSTFW) {
struct ct_buffer6 *ct_buffer;
__u32 zero = 0;
__u32 remote_id = WORLD_ID;
ct_buffer = map_lookup_elem(&CT_TAIL_CALL_BUFFER6, &zero);
if (!ct_buffer)
return DROP_INVALID_TC_BUFFER;
if (ct_buffer->tuple.saddr.d1 == 0 && ct_buffer->tuple.saddr.d2 == 0)
/* The map value is zeroed so the map update didn't happen somehow. */
return DROP_INVALID_TC_BUFFER;
if (from_host) {
bool is_host_id = from_host_raw & FROM_HOST_FLAG_HOST_ID;
ret = __ipv6_host_policy_egress(ctx, is_host_id, ip6, ct_buffer, &trace,
ext_err);
} else {
ret = __ipv6_host_policy_ingress(ctx, ip6, ct_buffer, &remote_id, &trace,
ext_err);
}
if (IS_ERR(ret))
return ret;
}
#endif /* ENABLE_HOST_FIREWALL */
/*
* Perform SRv6 Decap if incoming skb is a known SID.
* This must tailcall, as the decap could be for inner ipv6 or ipv4 making
* the remaining path potentially erroneous.
*
* Perform this before the ENABLE_HOST_ROUTING check as the decap is not dependent
* on this feature being enabled or not.
*/
#ifdef ENABLE_SRV6
if (!from_host) {
if (is_srv6_packet(ip6) && srv6_lookup_sid(&ip6->daddr)) {
/* This packet is destined to an SID so we need to decapsulate it
* and forward it.
*/
ep_tail_call(ctx, CILIUM_CALL_SRV6_DECAP);
return DROP_MISSED_TAIL_CALL;
}
}
#endif /* ENABLE_SRV6 */
#ifndef ENABLE_HOST_ROUTING
/* See the equivalent v4 path for comments */
if (!from_host)
return CTX_ACT_OK;
#endif /* !ENABLE_HOST_ROUTING */
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 IPv6 address in list of local endpoints */
ep = lookup_ip6_endpoint(ip6);
if (ep) {
bool l2_hdr_required __maybe_unused = true;
/* 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;
#ifdef ENABLE_HOST_ROUTING
/* add L2 header for L2-less interface, such as cilium_wg0 */
ret = maybe_add_l2_hdr(ctx, ep->ifindex, &l2_hdr_required);
if (ret != 0)
return ret;
if (l2_hdr_required && ETH_HLEN == 0) {
/* l2 header is added */
l3_off += __ETH_HLEN;
}
#endif
return ipv6_local_delivery(ctx, l3_off, secctx, ep,
METRIC_INGRESS, from_host, false);
}
/* 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;
dst = (union v6addr *) &ip6->daddr;
info = ipcache_lookup6(&IPCACHE_MAP, dst, V6_CACHE_KEY_LEN, 0);
#ifdef ENABLE_IPSEC
/* See IPv4 comment. */
if (from_ingress_proxy && info)
encrypt_key = get_min_encrypt_key(info->key);
#endif
#ifdef TUNNEL_MODE
if (info != NULL && info->tunnel_endpoint != 0) {
return encap_and_redirect_with_nodeid(ctx, info->tunnel_endpoint,
encrypt_key, secctx, info->sec_identity,
&trace);
} else {
struct tunnel_key key = {};
/* IPv6 lookup key: daddr/96 */
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, encrypt_key, secctx, &trace);
if (ret != DROP_NO_TUNNEL_ENDPOINT)
return ret;
}
#endif
if (!info || (!from_ingress_proxy &&
info->sec_identity == WORLD_ID)) {
/* See IPv4 comment. */
return DROP_UNROUTABLE;
}
#if defined(ENABLE_IPSEC) && !defined(TUNNEL_MODE)
/* See IPv4 comment. */
if (from_ingress_proxy && info->tunnel_endpoint && encrypt_key)
return set_ipsec_encrypt(ctx, encrypt_key, info->tunnel_endpoint,
info->sec_identity);
#endif
return CTX_ACT_OK;
}
static __always_inline int
tail_handle_ipv6_cont(struct __ctx_buff *ctx, bool from_host)
{
__u32 proxy_identity = ctx_load_meta(ctx, CB_SRC_LABEL);
int ret;
__s8 ext_err = 0;
ctx_store_meta(ctx, CB_SRC_LABEL, 0);
ret = handle_ipv6_cont(ctx, proxy_identity, from_host, &ext_err);
if (IS_ERR(ret))
return send_drop_notify_error_ext(ctx, proxy_identity, ret, ext_err,
CTX_ACT_DROP, METRIC_INGRESS);
return ret;
}
declare_tailcall_if(is_defined(ENABLE_HOST_FIREWALL), CILIUM_CALL_IPV6_CONT_FROM_HOST)
int tail_handle_ipv6_cont_from_host(struct __ctx_buff *ctx)
{
return tail_handle_ipv6_cont(ctx, true);
}
declare_tailcall_if(is_defined(ENABLE_HOST_FIREWALL), CILIUM_CALL_IPV6_CONT_FROM_NETDEV)
int tail_handle_ipv6_cont_from_netdev(struct __ctx_buff *ctx)
{
return tail_handle_ipv6_cont(ctx, false);
}
static __always_inline int
tail_handle_ipv6(struct __ctx_buff *ctx, __u32 ipcache_srcid, const bool from_host)
{
__u32 proxy_identity = ctx_load_meta(ctx, CB_SRC_LABEL);
int ret;
__s8 ext_err = 0;
ctx_store_meta(ctx, CB_SRC_LABEL, 0);
ret = handle_ipv6(ctx, proxy_identity, ipcache_srcid, from_host, &ext_err);
/* TC_ACT_REDIRECT is not an error, but it means we should stop here. */
if (ret == CTX_ACT_OK) {
ctx_store_meta(ctx, CB_SRC_LABEL, proxy_identity);
if (from_host)
ret = invoke_tailcall_if(is_defined(ENABLE_HOST_FIREWALL),
CILIUM_CALL_IPV6_CONT_FROM_HOST,
tail_handle_ipv6_cont_from_host);
else
ret = invoke_tailcall_if(is_defined(ENABLE_HOST_FIREWALL),
CILIUM_CALL_IPV6_CONT_FROM_NETDEV,
tail_handle_ipv6_cont_from_netdev);
}
/* Catch errors from both handle_ipv6 and invoke_tailcall_if here. */
if (IS_ERR(ret))
return send_drop_notify_error_ext(ctx, proxy_identity, ret, ext_err,
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)
{
__u32 ipcache_srcid = 0;
#if defined(ENABLE_HOST_FIREWALL) && !defined(ENABLE_MASQUERADE_IPV6)
ipcache_srcid = ctx_load_meta(ctx, CB_IPCACHE_SRC_LABEL);
ctx_store_meta(ctx, CB_IPCACHE_SRC_LABEL, 0);
#endif /* defined(ENABLE_HOST_FIREWALL) && !defined(ENABLE_MASQUERADE_IPV6) */
return tail_handle_ipv6(ctx, ipcache_srcid, true);
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV6_FROM_NETDEV)
int tail_handle_ipv6_from_netdev(struct __ctx_buff *ctx)
{
return tail_handle_ipv6(ctx, 0, false);
}
# ifdef ENABLE_HOST_FIREWALL
static __always_inline int
handle_to_netdev_ipv6(struct __ctx_buff *ctx, struct trace_ctx *trace, __s8 *ext_err)
{
void *data, *data_end;
struct ipv6hdr *ip6;
__u32 srcid = 0, ipcache_srcid = 0;
int hdrlen, ret;
__u8 nexthdr;
if (!revalidate_data_pull(ctx, &data, &data_end, &ip6))
return DROP_INVALID;
nexthdr = ip6->nexthdr;
hdrlen = ipv6_hdrlen(ctx, &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;
}
if ((ctx->mark & MARK_MAGIC_HOST_MASK) == MARK_MAGIC_HOST)
srcid = HOST_ID;
srcid = resolve_srcid_ipv6(ctx, ip6, srcid, &ipcache_srcid, true);
/* to-netdev is attached to the egress path of the native device. */
return ipv6_host_policy_egress(ctx, srcid, ipcache_srcid, ip6, trace, ext_err);
}
#endif /* ENABLE_HOST_FIREWALL */
#endif /* ENABLE_IPV6 */
#ifdef ENABLE_IPV4
static __always_inline __u32
resolve_srcid_ipv4(struct __ctx_buff *ctx, struct iphdr *ip4,
__u32 srcid_from_proxy, __u32 *sec_identity,
const bool from_host)
{
__u32 src_id = WORLD_ID, srcid_from_ipcache = srcid_from_proxy;
struct remote_endpoint_info *info = NULL;
/* Packets from the proxy will already have a real identity. */
if (identity_is_reserved(srcid_from_ipcache)) {
info = lookup_ip4_remote_endpoint(ip4->saddr, 0);
if (info != NULL) {
*sec_identity = info->sec_identity;
if (*sec_identity) {
/* 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.
*/
if (*sec_identity != HOST_ID)
srcid_from_ipcache = *sec_identity;
}
}
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())
src_id = srcid_from_ipcache;
return src_id;
}
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, __u32);
__type(value, struct ct_buffer4);
__uint(max_entries, 1);
} CT_TAIL_CALL_BUFFER4 __section_maps_btf;
static __always_inline int
handle_ipv4(struct __ctx_buff *ctx, __u32 secctx __maybe_unused,
__u32 ipcache_srcid __maybe_unused,
const bool from_host __maybe_unused,
__s8 *ext_err __maybe_unused)
{
#ifdef ENABLE_HOST_FIREWALL
struct ct_buffer4 ct_buffer = {};
bool need_hostfw = false;
bool is_host_id = false;
#endif /* ENABLE_HOST_FIREWALL */
void *data, *data_end;
struct iphdr *ip4;
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_skip_nodeport(ctx)) {
bool __maybe_unused is_dsr = false;
int ret = nodeport_lb4(ctx, ip4, ETH_HLEN, secctx, ext_err, &is_dsr);
if (ret == NAT_46X64_RECIRC) {
ctx_store_meta(ctx, CB_SRC_LABEL, secctx);
ep_tail_call(ctx, CILIUM_CALL_IPV6_FROM_NETDEV);
return DROP_MISSED_TAIL_CALL;
}
/* nodeport_lb4() returns with TC_ACT_REDIRECT for
* traffic to L7 LB. Policy enforcement needs to take
* place after L7 LB has processed the packet, so we
* return to stack immediately here with
* TC_ACT_REDIRECT.
*/
if (ret < 0 || ret == TC_ACT_REDIRECT)
return ret;
}
}
#endif /* ENABLE_NODEPORT */
#ifdef ENABLE_HOST_FIREWALL
if (from_host) {
/* We're on the egress path of cilium_host. */
if (ipv4_host_policy_egress_lookup(ctx, secctx, ipcache_srcid, ip4, &ct_buffer)) {
if (unlikely(ct_buffer.ret < 0))
return ct_buffer.ret;
need_hostfw = true;
is_host_id = secctx == HOST_ID;
}
} else if (!ctx_skip_host_fw(ctx)) {
/* Verifier workaround: R5 invalid mem access 'scalar'. */
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
/* We're on the ingress path of the native device. */
if (ipv4_host_policy_ingress_lookup(ctx, ip4, &ct_buffer)) {
if (unlikely(ct_buffer.ret < 0))
return ct_buffer.ret;
need_hostfw = true;
}
}
if (need_hostfw) {
__u32 zero = 0;
if (map_update_elem(&CT_TAIL_CALL_BUFFER4, &zero, &ct_buffer, 0) < 0)
return DROP_INVALID_TC_BUFFER;
}
ctx_store_meta(ctx, CB_FROM_HOST,
(need_hostfw ? FROM_HOST_FLAG_NEED_HOSTFW : 0) |
(is_host_id ? FROM_HOST_FLAG_HOST_ID : 0));
#endif /* ENABLE_HOST_FIREWALL */
return CTX_ACT_OK;
}
static __always_inline int
handle_ipv4_cont(struct __ctx_buff *ctx, __u32 secctx, const bool from_host,
__s8 *ext_err __maybe_unused)
{
struct trace_ctx __maybe_unused trace = {
.reason = TRACE_REASON_UNKNOWN,
.monitor = TRACE_PAYLOAD_LEN,
};
__u32 __maybe_unused from_host_raw;
void *data, *data_end;
struct iphdr *ip4;
struct remote_endpoint_info *info;
struct endpoint_info *ep;
int ret;
__u8 encrypt_key __maybe_unused = 0;
bool from_ingress_proxy = tc_index_from_ingress_proxy(ctx);
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
#ifdef ENABLE_HOST_FIREWALL
from_host_raw = ctx_load_meta(ctx, CB_FROM_HOST);
ctx_store_meta(ctx, CB_FROM_HOST, 0);
if (from_host_raw & FROM_HOST_FLAG_NEED_HOSTFW) {
struct ct_buffer4 *ct_buffer;
__u32 zero = 0;
__u32 remote_id = 0;
ct_buffer = map_lookup_elem(&CT_TAIL_CALL_BUFFER4, &zero);
if (!ct_buffer)
return DROP_INVALID_TC_BUFFER;
if (ct_buffer->tuple.saddr == 0)
/* The map value is zeroed so the map update didn't happen somehow. */
return DROP_INVALID_TC_BUFFER;
if (from_host) {
bool is_host_id = from_host_raw & FROM_HOST_FLAG_HOST_ID;
ret = __ipv4_host_policy_egress(ctx, is_host_id, ip4, ct_buffer, &trace,
ext_err);
} else {
ret = __ipv4_host_policy_ingress(ctx, ip4, ct_buffer, &remote_id, &trace,
ext_err);
}
if (IS_ERR(ret))
return ret;
}
#endif /* ENABLE_HOST_FIREWALL */
#ifndef ENABLE_HOST_ROUTING
/* 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)
return CTX_ACT_OK;
#endif /* !ENABLE_HOST_ROUTING */
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) {
bool l2_hdr_required __maybe_unused = true;
int l3_off __maybe_unused = ETH_HLEN;
/* 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;
#ifdef ENABLE_HOST_ROUTING
/* add L2 header for L2-less interface, such as cilium_wg0 */
ret = maybe_add_l2_hdr(ctx, ep->ifindex, &l2_hdr_required);
if (ret != 0)
return ret;
if (l2_hdr_required && ETH_HLEN == 0) {
/* l2 header is added */
l3_off += __ETH_HLEN;
if (!____revalidate_data_pull(ctx, &data, &data_end,
(void **)&ip4, sizeof(*ip4),
false, l3_off))
return DROP_INVALID;
}
#endif
return ipv4_local_delivery(ctx, l3_off, secctx, ip4, ep,
METRIC_INGRESS, from_host, false,
false, 0);
}
/* 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;
/* Handle VTEP integration in bpf_host to support pod L7 PROXY.
* It requires route setup to VTEP CIDR via dev cilium_host scope link.
*/
#ifdef ENABLE_VTEP
{
struct vtep_key vkey = {};
struct vtep_value *vtep;
vkey.vtep_ip = ip4->daddr & VTEP_MASK;
vtep = map_lookup_elem(&VTEP_MAP, &vkey);
if (!vtep)
goto skip_vtep;
if (vtep->vtep_mac && vtep->tunnel_endpoint) {
if (eth_store_daddr(ctx, (__u8 *)&vtep->vtep_mac, 0) < 0)
return DROP_WRITE_ERROR;
return __encap_and_redirect_with_nodeid(ctx, 0, vtep->tunnel_endpoint,
secctx, WORLD_ID, WORLD_ID, &trace);
}
}
skip_vtep:
#endif
info = ipcache_lookup4(&IPCACHE_MAP, ip4->daddr, V4_CACHE_KEY_LEN, 0);
#ifdef ENABLE_IPSEC
/* We encrypt host to remote pod packets only if they are from ingress proxy. */
if (from_ingress_proxy && info)
encrypt_key = get_min_encrypt_key(info->key);
#endif
#ifdef TUNNEL_MODE
if (info != NULL && info->tunnel_endpoint != 0) {
return encap_and_redirect_with_nodeid(ctx, info->tunnel_endpoint,
encrypt_key, secctx, info->sec_identity,
&trace);
} else {
/* IPv4 lookup key: daddr & IPV4_MASK */
struct tunnel_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, encrypt_key, secctx, &trace);
if (ret != DROP_NO_TUNNEL_ENDPOINT)
return ret;
}
#endif
if (!info || (!from_ingress_proxy &&
info->sec_identity == 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.
*
* Note that we do not drop packets from ingress proxy even if
* they are going to WORLD_ID. This is to avoid
* https://github.com/cilium/cilium/issues/21954.
*/
return DROP_UNROUTABLE;
}
#if defined(ENABLE_IPSEC) && !defined(TUNNEL_MODE)
/* We encrypt host to remote pod packets only if they are from ingress proxy. */
if (from_ingress_proxy && info->tunnel_endpoint && encrypt_key)
return set_ipsec_encrypt(ctx, encrypt_key, info->tunnel_endpoint,
info->sec_identity);
#endif
return CTX_ACT_OK;
}
static __always_inline int
tail_handle_ipv4_cont(struct __ctx_buff *ctx, bool from_host)
{
__u32 proxy_identity = ctx_load_meta(ctx, CB_SRC_LABEL);
int ret;
__s8 ext_err = 0;
ctx_store_meta(ctx, CB_SRC_LABEL, 0);
ret = handle_ipv4_cont(ctx, proxy_identity, from_host, &ext_err);
if (IS_ERR(ret))
return send_drop_notify_error_ext(ctx, proxy_identity, ret, ext_err,
CTX_ACT_DROP, METRIC_INGRESS);
return ret;
}
declare_tailcall_if(is_defined(ENABLE_HOST_FIREWALL), CILIUM_CALL_IPV4_CONT_FROM_HOST)
int tail_handle_ipv4_cont_from_host(struct __ctx_buff *ctx)
{
return tail_handle_ipv4_cont(ctx, true);
}
declare_tailcall_if(is_defined(ENABLE_HOST_FIREWALL), CILIUM_CALL_IPV4_CONT_FROM_NETDEV)
int tail_handle_ipv4_cont_from_netdev(struct __ctx_buff *ctx)
{
return tail_handle_ipv4_cont(ctx, false);
}
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_LABEL);
int ret;
__s8 ext_err = 0;
ctx_store_meta(ctx, CB_SRC_LABEL, 0);
ret = handle_ipv4(ctx, proxy_identity, ipcache_srcid, from_host, &ext_err);
/* TC_ACT_REDIRECT is not an error, but it means we should stop here. */
if (ret == CTX_ACT_OK) {
ctx_store_meta(ctx, CB_SRC_LABEL, proxy_identity);
if (from_host)
ret = invoke_tailcall_if(is_defined(ENABLE_HOST_FIREWALL),
CILIUM_CALL_IPV4_CONT_FROM_HOST,
tail_handle_ipv4_cont_from_host);
else
ret = invoke_tailcall_if(is_defined(ENABLE_HOST_FIREWALL),
CILIUM_CALL_IPV4_CONT_FROM_NETDEV,
tail_handle_ipv4_cont_from_netdev);
}
/* Catch errors from both handle_ipv4 and invoke_tailcall_if here. */
if (IS_ERR(ret))
return send_drop_notify_error_ext(ctx, proxy_identity, ret, ext_err,
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_IPV4)
ipcache_srcid = ctx_load_meta(ctx, CB_IPCACHE_SRC_LABEL);
ctx_store_meta(ctx, CB_IPCACHE_SRC_LABEL, 0);
#endif /* defined(ENABLE_HOST_FIREWALL) && !defined(ENABLE_MASQUERADE_IPV4) */
return tail_handle_ipv4(ctx, ipcache_srcid, true);
}
__section_tail(CILIUM_MAP_CALLS, CILIUM_CALL_IPV4_FROM_NETDEV)
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, struct trace_ctx *trace, __s8 *ext_err)
{
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;
if (!revalidate_data_pull(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
src_id = resolve_srcid_ipv4(ctx, ip4, src_id, &ipcache_srcid, true);
/* 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, ip4, trace, ext_err);
}
#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;
__u32 tunnel_endpoint = 0;
void *data, *data_end;
__u32 tunnel_source = IPV4_ENCRYPT_IFACE;
struct iphdr *ip4;
__be32 sum;
tunnel_endpoint = ctx_load_meta(ctx, CB_ENCRYPT_DST);
ctx->mark = 0;
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
/* We only need to replace the IPsec outer IP addresses if they are set to
* 0.0.0.0 -> 192.168.0.0. In that case, it means the packet was
* encapsulated by the old XFRM OUT state and we need this BPF logic.
* Otherwise, it means the packet was encapsulated by the new XFRM OUT
* states, which already set the proper outer IP addresses; nothing needed
* here.
* This whole function can be removed in 1.15.
*/
if (ip4->saddr != 0)
return 0;
/* 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(&ip4->daddr, sizeof(__u32), &tunnel_endpoint,
sizeof(tunnel_endpoint), 0);
if (ctx_store_bytes(ctx, ETH_HLEN + offsetof(struct iphdr, daddr),
&tunnel_endpoint, sizeof(tunnel_endpoint), 0) < 0)
return DROP_WRITE_ERROR;
if (l3_csum_replace(ctx, ETH_HLEN + offsetof(struct iphdr, check),
0, sum, 0) < 0)
return DROP_CSUM_L3;
if (!revalidate_data(ctx, &data, &data_end, &ip4))
return DROP_INVALID;
sum = csum_diff(&ip4->saddr, sizeof(__u32), &tunnel_source,
sizeof(tunnel_source), 0);
if (ctx_store_bytes(ctx, ETH_HLEN + offsetof(struct iphdr, saddr),
&tunnel_source, sizeof(tunnel_source), 0) < 0)
return DROP_WRITE_ERROR;
if (l3_csum_replace(ctx, ETH_HLEN + offsetof(struct iphdr, check),
0, sum, 0) < 0)
return DROP_CSUM_L3;
return ret;
}
static __always_inline int