tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2018 Facebook */
   3
   4 #include <stdlib.h>
   5 #include <linux/in.h>
   6 #include <linux/ip.h>
   7 #include <linux/ipv6.h>
   8 #include <linux/tcp.h>
   9 #include <linux/udp.h>
  10 #include <linux/bpf.h>
  11 #include <linux/types.h>
  12 #include <linux/if_ether.h>
  13
  14 #include <bpf/bpf_endian.h>
  15 #include <bpf/bpf_helpers.h>
  16 #include "test_select_reuseport_common.h"
  17
  18 int _version SEC("version") = 1;
  19
  20 #ifndef offsetof
  21 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
  22 #endif
  23
  24 struct {
  25         __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
  26         __uint(max_entries, 1);
  27         __uint(key_size, sizeof(__u32));
  28         __uint(value_size, sizeof(__u32));
  29 } outer_map SEC(".maps");
  30
  31 struct {
  32         __uint(type, BPF_MAP_TYPE_ARRAY);
  33         __uint(max_entries, NR_RESULTS);
  34         __type(key, __u32);
  35         __type(value, __u32);
  36 } result_map SEC(".maps");
  37
  38 struct {
  39         __uint(type, BPF_MAP_TYPE_ARRAY);
  40         __uint(max_entries, 1);
  41         __type(key, __u32);
  42         __type(value, int);
  43 } tmp_index_ovr_map SEC(".maps");
  44
  45 struct {
  46         __uint(type, BPF_MAP_TYPE_ARRAY);
  47         __uint(max_entries, 1);
  48         __type(key, __u32);
  49         __type(value, __u32);
  50 } linum_map SEC(".maps");
  51
  52 struct {
  53         __uint(type, BPF_MAP_TYPE_ARRAY);
  54         __uint(max_entries, 1);
  55         __type(key, __u32);
  56         __type(value, struct data_check);
  57 } data_check_map SEC(".maps");
  58
  59 #define GOTO_DONE(_result) ({                   \
  60         result = (_result);                     \
  61         linum = __LINE__;                       \
  62         goto done;                              \
  63 })
  64
  65 SEC("sk_reuseport")
  66 int _select_by_skb_data(struct sk_reuseport_md *reuse_md)
  67 {
  68         __u32 linum, index = 0, flags = 0, index_zero = 0;
  69         __u32 *result_cnt, *linum_value;
  70         struct data_check data_check = {};
  71         struct cmd *cmd, cmd_copy;
  72         void *data, *data_end;
  73         void *reuseport_array;
  74         enum result result;
  75         int *index_ovr;
  76         int err;
  77
  78         data = reuse_md->data;
  79         data_end = reuse_md->data_end;
  80         data_check.len = reuse_md->len;
  81         data_check.eth_protocol = reuse_md->eth_protocol;
  82         data_check.ip_protocol = reuse_md->ip_protocol;
  83         data_check.hash = reuse_md->hash;
  84         data_check.bind_inany = reuse_md->bind_inany;
  85         if (data_check.eth_protocol == bpf_htons(ETH_P_IP)) {
  86                 if (bpf_skb_load_bytes_relative(reuse_md,
  87                                                 offsetof(struct iphdr, saddr),
  88                                                 data_check.skb_addrs, 8,
  89                                                 BPF_HDR_START_NET))
  90                         GOTO_DONE(DROP_MISC);
  91         } else {
  92                 if (bpf_skb_load_bytes_relative(reuse_md,
  93                                                 offsetof(struct ipv6hdr, saddr),
  94                                                 data_check.skb_addrs, 32,
  95                                                 BPF_HDR_START_NET))
  96                         GOTO_DONE(DROP_MISC);
  97         }
  98
  99         /*
 100          * The ip_protocol could be a compile time decision
 101          * if the bpf_prog.o is dedicated to either TCP or
 102          * UDP.
 103          *
 104          * Otherwise, reuse_md->ip_protocol or
 105          * the protocol field in the iphdr can be used.
 106          */
 107         if (data_check.ip_protocol == IPPROTO_TCP) {
 108                 struct tcphdr *th = data;
 109
 110                 if (th + 1 > data_end)
 111                         GOTO_DONE(DROP_MISC);
 112
 113                 data_check.skb_ports[0] = th->source;
 114                 data_check.skb_ports[1] = th->dest;
 115
 116                 if (th->fin)
 117                         /* The connection is being torn down at the end of a
 118                          * test. It can't contain a cmd, so return early.
 119                          */
 120                         return SK_PASS;
 121
 122                 if ((th->doff << 2) + sizeof(*cmd) > data_check.len)
 123                         GOTO_DONE(DROP_ERR_SKB_DATA);
 124                 if (bpf_skb_load_bytes(reuse_md, th->doff << 2, &cmd_copy,
 125                                        sizeof(cmd_copy)))
 126                         GOTO_DONE(DROP_MISC);
 127                 cmd = &cmd_copy;
 128         } else if (data_check.ip_protocol == IPPROTO_UDP) {
 129                 struct udphdr *uh = data;
 130
 131                 if (uh + 1 > data_end)
 132                         GOTO_DONE(DROP_MISC);
 133
 134                 data_check.skb_ports[0] = uh->source;
 135                 data_check.skb_ports[1] = uh->dest;
 136
 137                 if (sizeof(struct udphdr) + sizeof(*cmd) > data_check.len)
 138                         GOTO_DONE(DROP_ERR_SKB_DATA);
 139                 if (data + sizeof(struct udphdr) + sizeof(*cmd) > data_end) {
 140                         if (bpf_skb_load_bytes(reuse_md, sizeof(struct udphdr),
 141                                                &cmd_copy, sizeof(cmd_copy)))
 142                                 GOTO_DONE(DROP_MISC);
 143                         cmd = &cmd_copy;
 144                 } else {
 145                         cmd = data + sizeof(struct udphdr);
 146                 }
 147         } else {
 148                 GOTO_DONE(DROP_MISC);
 149         }
 150
 151         reuseport_array = bpf_map_lookup_elem(&outer_map, &index_zero);
 152         if (!reuseport_array)
 153                 GOTO_DONE(DROP_ERR_INNER_MAP);
 154
 155         index = cmd->reuseport_index;
 156         index_ovr = bpf_map_lookup_elem(&tmp_index_ovr_map, &index_zero);
 157         if (!index_ovr)
 158                 GOTO_DONE(DROP_MISC);
 159
 160         if (*index_ovr != -1) {
 161                 index = *index_ovr;
 162                 *index_ovr = -1;
 163         }
 164         err = bpf_sk_select_reuseport(reuse_md, reuseport_array, &index,
 165                                       flags);
 166         if (!err)
 167                 GOTO_DONE(PASS);
 168
 169         if (cmd->pass_on_failure)
 170                 GOTO_DONE(PASS_ERR_SK_SELECT_REUSEPORT);
 171         else
 172                 GOTO_DONE(DROP_ERR_SK_SELECT_REUSEPORT);
 173
 174 done:
 175         result_cnt = bpf_map_lookup_elem(&result_map, &result);
 176         if (!result_cnt)
 177                 return SK_DROP;
 178
 179         bpf_map_update_elem(&linum_map, &index_zero, &linum, BPF_ANY);
 180         bpf_map_update_elem(&data_check_map, &index_zero, &data_check, BPF_ANY);
 181
 182         (*result_cnt)++;
 183         return result < PASS ? SK_DROP : SK_PASS;
 184 }
 185
 186 char _license[] SEC("license") = "GPL";