ifupdown-ng/libifupdown/lifecycle.c

330 lines
7.8 KiB
C

/*
* libifupdown/lifecycle.c
* Purpose: management of interface lifecycle (bring up, takedown, reload)
*
* Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* This software is provided 'as is' and without any warranty, express or
* implied. In no event shall the authors be liable for any damages arising
* from the use of this software.
*/
#include <ctype.h>
#include <string.h>
#include "libifupdown/environment.h"
#include "libifupdown/execute.h"
#include "libifupdown/interface.h"
#include "libifupdown/lifecycle.h"
#include "libifupdown/state.h"
#include "libifupdown/tokenize.h"
static bool
handle_commands_for_phase(const struct lif_execute_opts *opts, char *const envp[], struct lif_interface *iface, const char *lifname, const char *phase)
{
struct lif_node *iter;
(void) lifname;
LIF_DICT_FOREACH(iter, &iface->vars)
{
struct lif_dict_entry *entry = iter->data;
if (strcmp(entry->key, phase))
continue;
const char *cmd = entry->data;
if (!lif_execute_fmt(opts, envp, "%s", cmd))
return false;
}
return true;
}
static bool
handle_executors_for_phase(const struct lif_execute_opts *opts, char *const envp[], struct lif_interface *iface)
{
struct lif_node *iter;
LIF_DICT_FOREACH(iter, &iface->vars)
{
struct lif_dict_entry *entry = iter->data;
if (strcmp(entry->key, "use"))
continue;
const char *cmd = entry->data;
if (!lif_maybe_run_executor(opts, envp, cmd))
return false;
}
return true;
}
static inline size_t
count_set_bits(const char *netmask)
{
/* netmask set to CIDR length */
if (strchr(netmask, '.') == NULL)
return strtol(netmask, NULL, 10);
size_t r = 0;
struct in_addr in;
if (inet_pton(AF_INET, netmask, &in) == 0)
return r;
/* take the IP, put it in host endian order, and
* flip it so that all the set bits are set to the right.
* then we can simply count down from 32 and right-shift
* until the bit field is all zero.
*/
unsigned int bits = htonl(in.s_addr);
for (bits = ~bits, r = 32; bits; bits >>= 1, r--)
;
return r;
}
static bool
handle_pre_up(const struct lif_execute_opts *opts, struct lif_interface *iface, const char *lifname)
{
(void) opts;
(void) iface;
(void) lifname;
return true;
}
static bool
handle_up(const struct lif_execute_opts *opts, struct lif_interface *iface, const char *lifname)
{
(void) iface;
if (!lif_execute_fmt(opts, NULL, "/sbin/ip link set up dev %s", lifname))
return false;
return true;
}
static bool
handle_down(const struct lif_execute_opts *opts, struct lif_interface *iface, const char *lifname)
{
(void) iface;
if (!lif_execute_fmt(opts, NULL, "/sbin/ip link set down dev %s", lifname))
return false;
return true;
}
static bool
handle_post_down(const struct lif_execute_opts *opts, struct lif_interface *iface, const char *lifname)
{
(void) opts;
(void) iface;
(void) lifname;
return true;
}
bool
lif_lifecycle_run_phase(const struct lif_execute_opts *opts, struct lif_interface *iface, const char *phase, const char *lifname, bool up)
{
char **envp = NULL;
lif_environment_push(&envp, "IFACE", lifname);
lif_environment_push(&envp, "PHASE", phase);
/* try to provide $METHOD for ifupdown1 scripts if we can */
if (iface->is_dhcp)
lif_environment_push(&envp, "METHOD", "dhcp");
/* same for $MODE */
if (up)
lif_environment_push(&envp, "MODE", "start");
else
lif_environment_push(&envp, "MODE", "stop");
if (opts->verbose)
lif_environment_push(&envp, "VERBOSE", "1");
if (opts->interfaces_file)
lif_environment_push(&envp, "INTERFACES_FILE", opts->interfaces_file);
struct lif_node *iter;
bool did_address = false, did_gateway = false;
LIF_DICT_FOREACH(iter, &iface->vars)
{
struct lif_dict_entry *entry = iter->data;
if (!strcmp(entry->key, "address"))
{
if (did_address)
continue;
struct lif_address *addr = entry->data;
char addrbuf[4096];
if (!lif_address_unparse(addr, addrbuf, sizeof addrbuf, true))
continue;
lif_environment_push(&envp, "IF_ADDRESS", addrbuf);
did_address = true;
continue;
}
else if (!strcmp(entry->key, "gateway"))
{
if (did_gateway)
continue;
did_gateway = true;
}
else if (!strcmp(entry->key, "requires"))
{
if (iface->is_bridge)
lif_environment_push(&envp, "IF_BRIDGE_PORTS", (const char *) entry->data);
if (iface->is_bond)
lif_environment_push(&envp, "IF_BOND_SLAVES", (const char *) entry->data);
}
char envkey[4096] = "IF_";
strlcat(envkey, entry->key, sizeof envkey);
char *ep = envkey + 2;
while (*ep++)
{
*ep = toupper(*ep);
if (*ep == '-')
*ep = '_';
}
lif_environment_push(&envp, envkey, (const char *) entry->data);
}
if (!strcmp(phase, "pre-up"))
{
if (!handle_pre_up(opts, iface, lifname))
goto on_error;
}
else if (!strcmp(phase, "up"))
{
if (!handle_up(opts, iface, lifname))
goto on_error;
}
else if (!strcmp(phase, "down"))
{
if (!handle_down(opts, iface, lifname))
goto on_error;
}
else if (!strcmp(phase, "post-down"))
{
if (!handle_post_down(opts, iface, lifname))
goto on_error;
}
handle_executors_for_phase(opts, envp, iface);
handle_commands_for_phase(opts, envp, iface, lifname, phase);
/* we should do error handling here, but ifupdown1 doesn't */
lif_execute_fmt(opts, envp, "/bin/run-parts /etc/network/if-%s.d", phase);
lif_environment_free(&envp);
return true;
on_error:
lif_environment_free(&envp);
return false;
}
static bool
handle_dependents(const struct lif_execute_opts *opts, struct lif_interface *parent, struct lif_dict *collection, struct lif_dict *state, bool up)
{
struct lif_dict_entry *requires = lif_dict_find(&parent->vars, "requires");
/* no dependents, nothing to worry about */
if (requires == NULL)
return true;
char require_ifs[4096] = {};
strlcpy(require_ifs, requires->data, sizeof require_ifs);
char *bufp = require_ifs;
for (char *tokenp = lif_next_token(&bufp); *tokenp; tokenp = lif_next_token(&bufp))
{
struct lif_interface *iface = lif_interface_collection_find(collection, tokenp);
/* already up or down, skip */
if (up == iface->is_up)
continue;
if (opts->verbose)
fprintf(stderr, "ifupdown: changing state of dependent interface %s (of %s) to %s\n",
iface->ifname, parent->ifname, up ? "up" : "down");
if (!lif_lifecycle_run(opts, iface, collection, state, iface->ifname, up))
return false;
}
return true;
}
bool
lif_lifecycle_run(const struct lif_execute_opts *opts, struct lif_interface *iface, struct lif_dict *collection, struct lif_dict *state, const char *lifname, bool up)
{
if (lifname == NULL)
lifname = iface->ifname;
if (up)
{
/* when going up, dependents go up first. */
if (!handle_dependents(opts, iface, collection, state, up))
return false;
/* XXX: we should try to recover (take the iface down) if bringing it up fails.
* but, right now neither debian ifupdown or busybox ifupdown do any recovery,
* so we wont right now.
*/
if (!lif_lifecycle_run_phase(opts, iface, "pre-up", lifname, up))
return false;
if (!lif_lifecycle_run_phase(opts, iface, "up", lifname, up))
return false;
if (!lif_lifecycle_run_phase(opts, iface, "post-up", lifname, up))
return false;
lif_state_upsert(state, lifname, iface);
iface->is_up = true;
}
else
{
if (!lif_lifecycle_run_phase(opts, iface, "pre-down", lifname, up))
return false;
if (!lif_lifecycle_run_phase(opts, iface, "down", lifname, up))
return false;
if (!lif_lifecycle_run_phase(opts, iface, "post-down", lifname, up))
return false;
/* when going up, dependents go down last. */
if (!handle_dependents(opts, iface, collection, state, up))
return false;
lif_state_delete(state, lifname);
iface->is_up = false;
}
return true;
}