runns.h

/*
 * vim:et:sw=2:
 *
 * Copyright (c) 2019-2025 Nikita (sh1r4s3) Ermakov <sh1r4s3@mail.si-head.nl>
 * SPDX-License-Identifier: MIT
 */

#ifndef RUNNS_H
#define RUNNS_H

#define __USE_GNU
#define _XOPEN_SOURCE
#define __USE_XOPEN_EXTENDED
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <termios.h>
#include <netinet/in.h>
#include <fcntl.h>

#define STR_TOKEN(x) #x

// Linux socket default file.
#define DEFAULT_RUNNS_SOCKET "/var/run/runns/runns.socket"
#define RUNNS_MAXLEN sizeof(((struct sockaddr_un *)0)->sun_path)

// Maximum number of childs
#define MAX_CHILDS 1024

// librunns
#define ENV_SEPARATOR ':'

// Definitions of the flag bits:
// RUNNS_STOP -- wait for childs to exit and then exit.
// RUNNS_LIST -- list childs runned by runns.
// RUNNS_NPTS -- create control terminal for forked process.
#define RUNNS_STOP        (int)1 << 1
#define RUNNS_LIST        (int)1 << 2
#define RUNNS_NPTMS       (int)1 << 3

typedef enum {
  OP_MODE_UNK = 0,
  OP_MODE_NETNS,
  OP_MODE_FWD_PORT
} OP_MODES;

// common header for server and client
struct runns_header {
  size_t prog_sz;
  size_t netns_sz;
  size_t resolv_sz;
  size_t env_sz;
  size_t args_sz;
  unsigned int flag;
  struct termios tmode;
  OP_MODES op_mode;
};

struct runns_child {
  uid_t uid;
  pid_t pid;
};

// Structures for librunns
typedef enum {
  L4_PROTOCOL_UNK = 0,
  L4_PROTOCOL_TCP,
  L4_PROTOCOL_UDP
} L4_PROTOCOLS;

struct netns {
  unsigned char ip[sizeof(struct in6_addr)];
  int fd;             // File descriptor to clone a netns from
  sa_family_t family; // AF_INET or AF_INET6
  L4_PROTOCOLS proto; // TCP, UDP or unknown
  in_port_t port;
};

struct netns_list {
  struct netns node;
  struct netns_list *pnext;
};

#endif