samples/sockmap/sockmap_kern.c

   1 /* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10  * General Public License for more details.
  11  */
  12 #include <uapi/linux/bpf.h>
  13 #include <uapi/linux/if_ether.h>
  14 #include <uapi/linux/if_packet.h>
  15 #include <uapi/linux/ip.h>
  16 #include "../../tools/testing/selftests/bpf/bpf_helpers.h"
  17 #include "../../tools/testing/selftests/bpf/bpf_endian.h"
  18
  19 /* Sockmap sample program connects a client and a backend together
  20  * using cgroups.
  21  *
  22  *    client:X <---> frontend:80 client:X <---> backend:80
  23  *
  24  * For simplicity we hard code values here and bind 1:1. The hard
  25  * coded values are part of the setup in sockmap.sh script that
  26  * is associated with this BPF program.
  27  *
  28  * The bpf_printk is verbose and prints information as connections
  29  * are established and verdicts are decided.
  30  */
  31
  32 #define bpf_printk(fmt, ...)                                    \
  33 ({                                                              \
  34                char ____fmt[] = fmt;                            \
  35                bpf_trace_printk(____fmt, sizeof(____fmt),       \
  36                                 ##__VA_ARGS__);                 \
  37 })
  38
  39 struct bpf_map_def SEC("maps") sock_map = {
  40         .type = BPF_MAP_TYPE_SOCKMAP,
  41         .key_size = sizeof(int),
  42         .value_size = sizeof(int),
  43         .max_entries = 20,
  44 };
  45
  46 SEC("sk_skb1")
  47 int bpf_prog1(struct __sk_buff *skb)
  48 {
  49         return skb->len;
  50 }
  51
  52 SEC("sk_skb2")
  53 int bpf_prog2(struct __sk_buff *skb)
  54 {
  55         __u32 lport = skb->local_port;
  56         __u32 rport = skb->remote_port;
  57         int ret = 0;
  58
  59         if (lport == 10000)
  60                 ret = 10;
  61         else
  62                 ret = 1;
  63
  64         bpf_printk("sockmap: %d -> %d @ %d\n", lport, bpf_ntohl(rport), ret);
  65         return bpf_sk_redirect_map(skb, &sock_map, ret, 0);
  66 }
  67
  68 SEC("sockops")
  69 int bpf_sockmap(struct bpf_sock_ops *skops)
  70 {
  71         __u32 lport, rport;
  72         int op, err = 0, index, key, ret;
  73
  74
  75         op = (int) skops->op;
  76
  77         switch (op) {
  78         case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
  79                 lport = skops->local_port;
  80                 rport = skops->remote_port;
  81
  82                 if (lport == 10000) {
  83                         ret = 1;
  84                         err = bpf_sock_map_update(skops, &sock_map, &ret,
  85                                                   BPF_NOEXIST);
  86                         bpf_printk("passive(%i -> %i) map ctx update err: %d\n",
  87                                    lport, bpf_ntohl(rport), err);
  88                 }
  89                 break;
  90         case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
  91                 lport = skops->local_port;
  92                 rport = skops->remote_port;
  93
  94                 if (bpf_ntohl(rport) == 10001) {
  95                         ret = 10;
  96                         err = bpf_sock_map_update(skops, &sock_map, &ret,
  97                                                   BPF_NOEXIST);
  98                         bpf_printk("active(%i -> %i) map ctx update err: %d\n",
  99                                    lport, bpf_ntohl(rport), err);
 100                 }
 101                 break;
 102         default:
 103                 break;
 104         }
 105
 106         return 0;
 107 }
 108 char _license[] SEC("license") = "GPL";