include/bpf_scm.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __BPF_SCM__
   3 #define __BPF_SCM__
   4
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <sys/un.h>
   8
   9 #include "utils.h"
  10 #include "bpf_elf.h"
  11
  12 #define BPF_SCM_AUX_VER         1
  13 #define BPF_SCM_MAX_FDS         ELF_MAX_MAPS
  14 #define BPF_SCM_MSG_SIZE        1024
  15
  16 struct bpf_elf_st {
  17         dev_t st_dev;
  18         ino_t st_ino;
  19 };
  20
  21 struct bpf_map_aux {
  22         unsigned short uds_ver;
  23         unsigned short num_ent;
  24         char obj_name[64];
  25         struct bpf_elf_st obj_st;
  26         struct bpf_elf_map ent[BPF_SCM_MAX_FDS];
  27 };
  28
  29 struct bpf_map_set_msg {
  30         struct msghdr hdr;
  31         struct iovec iov;
  32         char msg_buf[BPF_SCM_MSG_SIZE];
  33         struct bpf_map_aux aux;
  34 };
  35
  36 static inline int *bpf_map_set_init(struct bpf_map_set_msg *msg,
  37                                     struct sockaddr_un *addr,
  38                                     unsigned int addr_len)
  39 {
  40         const unsigned int cmsg_ctl_len = sizeof(int) * BPF_SCM_MAX_FDS;
  41         struct cmsghdr *cmsg;
  42
  43         msg->iov.iov_base = &msg->aux;
  44         msg->iov.iov_len = sizeof(msg->aux);
  45
  46         msg->hdr.msg_iov = &msg->iov;
  47         msg->hdr.msg_iovlen = 1;
  48
  49         msg->hdr.msg_name = (struct sockaddr *)addr;
  50         msg->hdr.msg_namelen = addr_len;
  51
  52         BUILD_BUG_ON(sizeof(msg->msg_buf) < cmsg_ctl_len);
  53         msg->hdr.msg_control = &msg->msg_buf;
  54         msg->hdr.msg_controllen = cmsg_ctl_len;
  55
  56         cmsg = CMSG_FIRSTHDR(&msg->hdr);
  57         cmsg->cmsg_len = msg->hdr.msg_controllen;
  58         cmsg->cmsg_level = SOL_SOCKET;
  59         cmsg->cmsg_type = SCM_RIGHTS;
  60
  61         return (int *)CMSG_DATA(cmsg);
  62 }
  63
  64 static inline void bpf_map_set_init_single(struct bpf_map_set_msg *msg,
  65                                            int num)
  66 {
  67         struct cmsghdr *cmsg;
  68
  69         msg->hdr.msg_controllen = CMSG_LEN(sizeof(int) * num);
  70         msg->iov.iov_len = offsetof(struct bpf_map_aux, ent) +
  71                            sizeof(struct bpf_elf_map) * num;
  72
  73         cmsg = CMSG_FIRSTHDR(&msg->hdr);
  74         cmsg->cmsg_len = msg->hdr.msg_controllen;
  75 }
  76
  77 #endif /* __BPF_SCM__ */