view src/dhcpcd.h @ 5231:a2c342295221 draft

privsep: Enable Capsicum for all processes. Except for the priviledged process. This is quite an in-depth change: * ARP is now one process per address * BPF flags are now returned via privsep * BPF write filters are locked when supported * The root process sends to the network The last step is done by opening RAW sockets and then sending a UDP header (where applicable) to avoid binding to an address which is already in use by the reader sockets. This is slightly wasteful for OS's without sandboxing but does have the very nice side effect of not needing a source address to unicast DHCPs replies from which makes the code smaller.
author Roy Marples <roy@marples.name>
date Tue, 19 May 2020 16:19:05 +0100
parents 7406014c9120
children ee23398a68db
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/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * dhcpcd - DHCP client daemon
 * Copyright (c) 2006-2020 Roy Marples <roy@marples.name>
 * All rights reserved

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef DHCPCD_H
#define DHCPCD_H

#include <sys/socket.h>
#include <net/if.h>

#include <stdio.h>

#include "config.h"
#ifdef HAVE_SYS_QUEUE_H
#include <sys/queue.h>
#endif

#include "defs.h"
#include "control.h"
#include "if-options.h"

#define HWADDR_LEN	20
#define IF_SSIDLEN	32
#define PROFILE_LEN	64
#define SECRET_LEN	64

#define IF_INACTIVE	0
#define IF_ACTIVE	1
#define IF_ACTIVE_USER	2

#define	LINK_UP		1
#define	LINK_UNKNOWN	0
#define	LINK_DOWN	-1
#define	LINK_DOWN_IFFUP	-2

#define IF_DATA_IPV4	0
#define IF_DATA_ARP	1
#define IF_DATA_IPV4LL	2
#define IF_DATA_DHCP	3
#define IF_DATA_IPV6	4
#define IF_DATA_IPV6ND	5
#define IF_DATA_DHCP6	6
#define IF_DATA_MAX	7

/* If the interface does not support carrier status (ie PPP),
 * dhcpcd can poll it for the relevant flags periodically */
#define IF_POLL_UP	100	/* milliseconds */

#ifdef __QNX__
/* QNX carries defines for, but does not actually support PF_LINK */
#undef IFLR_ACTIVE
#endif

struct interface {
	struct dhcpcd_ctx *ctx;
	TAILQ_ENTRY(interface) next;
	char name[IF_NAMESIZE];
	unsigned int index;
	unsigned int active;
	unsigned int flags;
	uint16_t hwtype; /* ARPHRD_ETHER for example */
	unsigned char hwaddr[HWADDR_LEN];
	uint8_t hwlen;
	unsigned short vlanid;
	unsigned int metric;
	int carrier;
	bool wireless;
	uint8_t ssid[IF_SSIDLEN];
	unsigned int ssid_len;

	char profile[PROFILE_LEN];
	struct if_options *options;
	void *if_data[IF_DATA_MAX];
};
TAILQ_HEAD(if_head, interface);

#include "privsep.h"

#ifdef INET6
/* dhcpcd requires CMSG_SPACE to evaluate to a compile time constant. */
#if defined(__QNX) || \
	(defined(__NetBSD_Version__) && __NetBSD_Version__ < 600000000)
#undef CMSG_SPACE
#endif

#ifndef ALIGNBYTES
#define ALIGNBYTES (sizeof(int) - 1)
#endif
#ifndef ALIGN
#define	ALIGN(p) (((unsigned int)(p) + ALIGNBYTES) & ~ALIGNBYTES)
#endif
#ifndef CMSG_SPACE
#define	CMSG_SPACE(len)	(ALIGN(sizeof(struct cmsghdr)) + ALIGN(len))
#endif

#define IP6BUFLEN	(CMSG_SPACE(sizeof(struct in6_pktinfo)) + \
			CMSG_SPACE(sizeof(int)))
#endif

struct passwd;

struct dhcpcd_ctx {
	char pidfile[sizeof(PIDFILE) + IF_NAMESIZE + 1];
	char vendor[256];
	int fork_fd;	/* FD for the fork init signal pipe */
	const char *cffile;
	unsigned long long options;
	char *logfile;
	int argc;
	char **argv;
	int ifac;	/* allowed interfaces */
	char **ifav;	/* allowed interfaces */
	int ifdc;	/* denied interfaces */
	char **ifdv;	/* denied interfaces */
	int ifc;	/* listed interfaces */
	char **ifv;	/* listed interfaces */
	int ifcc;	/* configured interfaces */
	char **ifcv;	/* configured interfaces */
	unsigned char *duid;
	size_t duid_len;
	struct if_head *ifaces;

	rb_tree_t routes;	/* our routes */
#ifdef RT_FREE_ROUTE_TABLE
	rb_tree_t froutes;	/* free routes for re-use */
#endif
	size_t rt_order;	/* route order storage */

	int pf_inet_fd;
	void *priv;
	int link_fd;
#ifndef SMALL
	int link_rcvbuf;
#endif
	int seq;	/* route message sequence no */
	int sseq;	/* successful seq no sent */

#ifdef USE_SIGNALS
	sigset_t sigset;
#endif
	struct eloop *eloop;

#ifdef HAVE_OPEN_MEMSTREAM
	FILE *script_fp;
#endif
	char *script_buf;
	size_t script_buflen;
	char **script_env;
	size_t script_envlen;

	int control_fd;
	int control_unpriv_fd;
	struct fd_list_head control_fds;
	char control_sock[sizeof(CONTROLSOCKET) + IF_NAMESIZE];
	gid_t control_group;

	/* DHCP Enterprise options, RFC3925 */
	struct dhcp_opt *vivso;
	size_t vivso_len;

	char *randomstate; /* original state */

	/* For filtering RTM_MISS messages per router */
#ifdef BSD
	uint8_t *rt_missfilter;
	size_t rt_missfilterlen;
	size_t rt_missfiltersize;
#endif

#ifdef PRIVSEP
	struct passwd *ps_user;	/* struct passwd for privsep user */
	pid_t ps_root_pid;
	int ps_root_fd;		/* Privileged Actioneer commands */
	int ps_data_fd;		/* Data from root spawned processes */
	struct eloop *ps_eloop;	/* eloop for polling root data */
	struct ps_process_head ps_processes;	/* List of spawned processes */
	pid_t ps_inet_pid;
	int ps_inet_fd;		/* Network Proxy commands and data */
#endif

#ifdef INET
	struct dhcp_opt *dhcp_opts;
	size_t dhcp_opts_len;

	int udp_rfd;
	int udp_wfd;

	/* Our aggregate option buffer.
	 * We ONLY use this when options are split, which for most purposes is
	 * practically never. See RFC3396 for details. */
	uint8_t *opt_buffer;
	size_t opt_buffer_len;
#endif
#ifdef INET6
	uint8_t *secret;
	size_t secret_len;

#ifndef __sun
	int nd_fd;
#endif
	struct ra_head *ra_routers;

	struct dhcp_opt *nd_opts;
	size_t nd_opts_len;
#ifdef DHCP6
	int dhcp6_rfd;
	int dhcp6_wfd;
	struct dhcp_opt *dhcp6_opts;
	size_t dhcp6_opts_len;
#endif

#ifndef __linux__
	int ra_global;
#endif
#endif /* INET6 */

#ifdef PLUGIN_DEV
	char *dev_load;
	int dev_fd;
	struct dev *dev;
	void *dev_handle;
#endif
};

#ifdef USE_SIGNALS
extern const int dhcpcd_signals[];
extern const size_t dhcpcd_signals_len;
extern const int dhcpcd_signals_ignore[];
extern const size_t dhcpcd_signals_ignore_len;
#endif

int dhcpcd_ifafwaiting(const struct interface *);
int dhcpcd_afwaiting(const struct dhcpcd_ctx *);
void dhcpcd_daemonise(struct dhcpcd_ctx *);

void dhcpcd_linkoverflow(struct dhcpcd_ctx *);
int dhcpcd_handleargs(struct dhcpcd_ctx *, struct fd_list *, int, char **);
void dhcpcd_handlecarrier(struct dhcpcd_ctx *, int, unsigned int, const char *);
int dhcpcd_handleinterface(void *, int, const char *);
void dhcpcd_handlehwaddr(struct interface *, uint16_t, const void *, uint8_t);
void dhcpcd_dropinterface(struct interface *, const char *);
int dhcpcd_selectprofile(struct interface *, const char *);

void dhcpcd_startinterface(void *);
void dhcpcd_activateinterface(struct interface *, unsigned long long);

#endif