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

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Check if we can migrate child sockets.
   4 *
   5 *   1. If reuse_md->migrating_sk is NULL (SYN packet),
   6 *        return SK_PASS without selecting a listener.
   7 *   2. If reuse_md->migrating_sk is not NULL (socket migration),
   8 *        select a listener (reuseport_map[migrate_map[cookie]])
   9 *
  10 * Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
  11 */
  12
  13#include <stddef.h>
  14#include <string.h>
  15#include <linux/bpf.h>
  16#include <linux/if_ether.h>
  17#include <linux/ip.h>
  18#include <linux/ipv6.h>
  19#include <linux/tcp.h>
  20#include <linux/in.h>
  21#include <bpf/bpf_endian.h>
  22#include <bpf/bpf_helpers.h>
  23
  24struct {
  25        __uint(type, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY);
  26        __uint(max_entries, 256);
  27        __type(key, int);
  28        __type(value, __u64);
  29} reuseport_map SEC(".maps");
  30
  31struct {
  32        __uint(type, BPF_MAP_TYPE_HASH);
  33        __uint(max_entries, 256);
  34        __type(key, __u64);
  35        __type(value, int);
  36} migrate_map SEC(".maps");
  37
  38int migrated_at_close = 0;
  39int migrated_at_close_fastopen = 0;
  40int migrated_at_send_synack = 0;
  41int migrated_at_recv_ack = 0;
  42__be16 server_port;
  43
  44SEC("xdp")
  45int drop_ack(struct xdp_md *xdp)
  46{
  47        void *data_end = (void *)(long)xdp->data_end;
  48        void *data = (void *)(long)xdp->data;
  49        struct ethhdr *eth = data;
  50        struct tcphdr *tcp = NULL;
  51
  52        if (eth + 1 > data_end)
  53                goto pass;
  54
  55        switch (bpf_ntohs(eth->h_proto)) {
  56        case ETH_P_IP: {
  57                struct iphdr *ip = (struct iphdr *)(eth + 1);
  58
  59                if (ip + 1 > data_end)
  60                        goto pass;
  61
  62                if (ip->protocol != IPPROTO_TCP)
  63                        goto pass;
  64
  65                tcp = (struct tcphdr *)((void *)ip + ip->ihl * 4);
  66                break;
  67        }
  68        case ETH_P_IPV6: {
  69                struct ipv6hdr *ipv6 = (struct ipv6hdr *)(eth + 1);
  70
  71                if (ipv6 + 1 > data_end)
  72                        goto pass;
  73
  74                if (ipv6->nexthdr != IPPROTO_TCP)
  75                        goto pass;
  76
  77                tcp = (struct tcphdr *)(ipv6 + 1);
  78                break;
  79        }
  80        default:
  81                goto pass;
  82        }
  83
  84        if (tcp + 1 > data_end)
  85                goto pass;
  86
  87        if (tcp->dest != server_port)
  88                goto pass;
  89
  90        if (!tcp->syn && tcp->ack)
  91                return XDP_DROP;
  92
  93pass:
  94        return XDP_PASS;
  95}
  96
  97SEC("sk_reuseport/migrate")
  98int migrate_reuseport(struct sk_reuseport_md *reuse_md)
  99{
 100        int *key, flags = 0, state, err;
 101        __u64 cookie;
 102
 103        if (!reuse_md->migrating_sk)
 104                return SK_PASS;
 105
 106        state = reuse_md->migrating_sk->state;
 107        cookie = bpf_get_socket_cookie(reuse_md->sk);
 108
 109        key = bpf_map_lookup_elem(&migrate_map, &cookie);
 110        if (!key)
 111                return SK_DROP;
 112
 113        err = bpf_sk_select_reuseport(reuse_md, &reuseport_map, key, flags);
 114        if (err)
 115                return SK_PASS;
 116
 117        switch (state) {
 118        case BPF_TCP_ESTABLISHED:
 119                __sync_fetch_and_add(&migrated_at_close, 1);
 120                break;
 121        case BPF_TCP_SYN_RECV:
 122                __sync_fetch_and_add(&migrated_at_close_fastopen, 1);
 123                break;
 124        case BPF_TCP_NEW_SYN_RECV:
 125                if (!reuse_md->len)
 126                        __sync_fetch_and_add(&migrated_at_send_synack, 1);
 127                else
 128                        __sync_fetch_and_add(&migrated_at_recv_ack, 1);
 129                break;
 130        }
 131
 132        return SK_PASS;
 133}
 134
 135char _license[] SEC("license") = "GPL";
 136