LXR linux/tools/testing/selftests/bpf/progs/cgroup_skb_sk_lookup

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (c) 2020 Facebook
   3
   4#include <linux/bpf.h>
   5#include <bpf/bpf_endian.h>
   6#include <bpf/bpf_helpers.h>
   7
   8#include <linux/if_ether.h>
   9#include <linux/in.h>
  10#include <linux/in6.h>
  11#include <linux/ipv6.h>
  12#include <linux/tcp.h>
  13
  14#include <sys/types.h>
  15#include <sys/socket.h>
  16
  17int _version SEC("version") = 1;
  18char _license[] SEC("license") = "GPL";
  19
  20__u16 g_serv_port = 0;
  21
  22static inline void set_ip(__u32 *dst, const struct in6_addr *src)
  23{
  24        dst[0] = src->in6_u.u6_addr32[0];
  25        dst[1] = src->in6_u.u6_addr32[1];
  26        dst[2] = src->in6_u.u6_addr32[2];
  27        dst[3] = src->in6_u.u6_addr32[3];
  28}
  29
  30static inline void set_tuple(struct bpf_sock_tuple *tuple,
  31                             const struct ipv6hdr *ip6h,
  32                             const struct tcphdr *tcph)
  33{
  34        set_ip(tuple->ipv6.saddr, &ip6h->daddr);
  35        set_ip(tuple->ipv6.daddr, &ip6h->saddr);
  36        tuple->ipv6.sport = tcph->dest;
  37        tuple->ipv6.dport = tcph->source;
  38}
  39
  40static inline int is_allowed_peer_cg(struct __sk_buff *skb,
  41                                     const struct ipv6hdr *ip6h,
  42                                     const struct tcphdr *tcph)
  43{
  44        __u64 cgid, acgid, peer_cgid, peer_acgid;
  45        struct bpf_sock_tuple tuple;
  46        size_t tuple_len = sizeof(tuple.ipv6);
  47        struct bpf_sock *peer_sk;
  48
  49        set_tuple(&tuple, ip6h, tcph);
  50
  51        peer_sk = bpf_sk_lookup_tcp(skb, &tuple, tuple_len,
  52                                    BPF_F_CURRENT_NETNS, 0);
  53        if (!peer_sk)
  54                return 0;
  55
  56        cgid = bpf_skb_cgroup_id(skb);
  57        peer_cgid = bpf_sk_cgroup_id(peer_sk);
  58
  59        acgid = bpf_skb_ancestor_cgroup_id(skb, 2);
  60        peer_acgid = bpf_sk_ancestor_cgroup_id(peer_sk, 2);
  61
  62        bpf_sk_release(peer_sk);
  63
  64        return cgid && cgid == peer_cgid && acgid && acgid == peer_acgid;
  65}
  66
  67SEC("cgroup_skb/ingress")
  68int ingress_lookup(struct __sk_buff *skb)
  69{
  70        __u32 serv_port_key = 0;
  71        struct ipv6hdr ip6h;
  72        struct tcphdr tcph;
  73
  74        if (skb->protocol != bpf_htons(ETH_P_IPV6))
  75                return 1;
  76
  77        /* For SYN packets coming to listening socket skb->remote_port will be
  78         * zero, so IPv6/TCP headers are loaded to identify remote peer
  79         * instead.
  80         */
  81        if (bpf_skb_load_bytes(skb, 0, &ip6h, sizeof(ip6h)))
  82                return 1;
  83
  84        if (ip6h.nexthdr != IPPROTO_TCP)
  85                return 1;
  86
  87        if (bpf_skb_load_bytes(skb, sizeof(ip6h), &tcph, sizeof(tcph)))
  88                return 1;
  89
  90        if (!g_serv_port)
  91                return 0;
  92
  93        if (tcph.dest != g_serv_port)
  94                return 1;
  95
  96        return is_allowed_peer_cg(skb, &ip6h, &tcph);
  97}
  98