// SPDX-License-Identifier: GPL-2.0
|
#include <string.h>
|
|
#include <linux/bpf.h>
|
#include <linux/in.h>
|
#include <linux/in6.h>
|
#include <sys/socket.h>
|
|
#include <bpf/bpf_helpers.h>
|
#include <bpf/bpf_endian.h>
|
|
char _license[] SEC("license") = "GPL";
|
int _version SEC("version") = 1;
|
|
struct svc_addr {
|
__be32 addr[4];
|
__be16 port;
|
};
|
|
struct {
|
__uint(type, BPF_MAP_TYPE_SK_STORAGE);
|
__uint(map_flags, BPF_F_NO_PREALLOC);
|
__type(key, int);
|
__type(value, struct svc_addr);
|
} service_mapping SEC(".maps");
|
|
SEC("cgroup/connect6")
|
int connect6(struct bpf_sock_addr *ctx)
|
{
|
struct sockaddr_in6 sa = {};
|
struct svc_addr *orig;
|
|
/* Force local address to [::1]:22223. */
|
sa.sin6_family = AF_INET6;
|
sa.sin6_port = bpf_htons(22223);
|
sa.sin6_addr.s6_addr32[3] = bpf_htonl(1);
|
|
if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
|
return 0;
|
|
/* Rewire service [fc00::1]:60000 to backend [::1]:60124. */
|
if (ctx->user_port == bpf_htons(60000)) {
|
orig = bpf_sk_storage_get(&service_mapping, ctx->sk, 0,
|
BPF_SK_STORAGE_GET_F_CREATE);
|
if (!orig)
|
return 0;
|
|
orig->addr[0] = ctx->user_ip6[0];
|
orig->addr[1] = ctx->user_ip6[1];
|
orig->addr[2] = ctx->user_ip6[2];
|
orig->addr[3] = ctx->user_ip6[3];
|
orig->port = ctx->user_port;
|
|
ctx->user_ip6[0] = 0;
|
ctx->user_ip6[1] = 0;
|
ctx->user_ip6[2] = 0;
|
ctx->user_ip6[3] = bpf_htonl(1);
|
ctx->user_port = bpf_htons(60124);
|
}
|
return 1;
|
}
|
|
SEC("cgroup/getsockname6")
|
int getsockname6(struct bpf_sock_addr *ctx)
|
{
|
/* Expose local server as [fc00::1]:60000 to client. */
|
if (ctx->user_port == bpf_htons(60124)) {
|
ctx->user_ip6[0] = bpf_htonl(0xfc000000);
|
ctx->user_ip6[1] = 0;
|
ctx->user_ip6[2] = 0;
|
ctx->user_ip6[3] = bpf_htonl(1);
|
ctx->user_port = bpf_htons(60000);
|
}
|
return 1;
|
}
|
|
SEC("cgroup/getpeername6")
|
int getpeername6(struct bpf_sock_addr *ctx)
|
{
|
struct svc_addr *orig;
|
|
/* Expose service [fc00::1]:60000 as peer instead of backend. */
|
if (ctx->user_port == bpf_htons(60124)) {
|
orig = bpf_sk_storage_get(&service_mapping, ctx->sk, 0, 0);
|
if (orig) {
|
ctx->user_ip6[0] = orig->addr[0];
|
ctx->user_ip6[1] = orig->addr[1];
|
ctx->user_ip6[2] = orig->addr[2];
|
ctx->user_ip6[3] = orig->addr[3];
|
ctx->user_port = orig->port;
|
}
|
}
|
return 1;
|
}
|
