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Remove ifsPrevState and set non-infinite timeout on a send error.

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We instead check carrier status as needed.  This approach is more
robust.  For a simple example, imagine link state changes that happen
while the machine is suspended.
This commit is contained in:
Nicholas J. Kain 2017-01-12 06:05:00 -05:00
parent c47630ffca
commit 29498f5341
4 changed files with 34 additions and 61 deletions
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49
src/ndhc.c
View File

@ -260,8 +260,7 @@ static void fail_if_state_dir_dne(void)
static void do_ndhc_work(void)
{
static bool rfkill_set; // Is the rfkill switch set?
static bool rfkill_nl_state_changed; // iface state changed during rfkill
static int rfkill_nl_state; // current iface state during rfkill
static bool rfkill_nl_carrier_wentup; // iface carrier changed to up during rfkill
struct dhcpmsg dhcp_packet;
struct epoll_event events[1];
long long nowts;
@ -333,45 +332,33 @@ static void do_ndhc_work(void)
sev_rfk = rfkill_get(&cs, 1, client_config.rfkillIdx);
} else
suicide("epoll_wait: unknown fd");
}
if (sev_rfk == RFK_ENABLED) {
rfkill_set = 1;
rfkill_nl_state = cs.ifsPrevState;
rfkill_nl_state_changed = false;
rfkill_nl_carrier_wentup = false;
log_line("rfkill: radio now blocked");
} else if (sev_rfk == RFK_DISABLED) {
rfkill_set = 0;
log_line("rfkill: radio now unblocked");
// We now simulate the state changes that may have happened
// during rfkill.
if (rfkill_nl_state != cs.ifsPrevState)
nl_event_react(&cs, rfkill_nl_state);
else if (rfkill_nl_state_changed && rfkill_nl_state == IFS_UP) {
// We might have changed networks even if we ended up
// back in IFS_UP state. We need to fingerprint the
// network and confirm that we're on the same network.
if (rfkill_nl_carrier_wentup && carrier_isup()) {
// We might have changed networks while the radio was down.
force_fingerprint = true;
}
}
}
if (sev_nl != IFS_NONE) {
if (!rfkill_set) {
if (nl_event_react(&cs, sev_nl))
if (sev_nl != IFS_NONE && nl_event_carrier_wentup(sev_nl)) {
if (!rfkill_set)
force_fingerprint = true;
} else {
// Store the state so it can be replayed later.
rfkill_nl_state_changed = true;
rfkill_nl_state = sev_nl;
}
else
rfkill_nl_carrier_wentup = true;
}
if (rfkill_set || cs.ifsPrevState != IFS_UP) {
if (rfkill_set || !carrier_isup()) {
// We can't do anything while the iface is disabled, anyway.
// XXX: It may be smart to set a non-infinite timeout
// and periodically poll to see if the rfkill or iface
// state changed; it might happen during suspend.
timeout = -1;
// Suspend might cause link state change notifications to be
// missed, so we use a non-infinite timeout.
timeout = 2000 + nk_random_u32(&cs.rnd32_state) % 3000;
continue;
}
@ -385,11 +372,8 @@ static void do_ndhc_work(void)
if (sev_arp)
arp_reply_clear();
// XXX: Would be best if we detected RFKILL being set via an
// error message and propagated it back to here as a
// distinct return value.
if (dhcp_ok == COR_ERROR) {
timeout = -1;
timeout = 2000 + nk_random_u32(&cs.rnd32_state) % 3000;
continue;
}
@ -500,7 +484,7 @@ static void ndhc_main(void) {
memset(chroot_dir, '\0', sizeof chroot_dir);
nk_set_uidgid(ndhc_uid, ndhc_gid, NULL, 0);
if (cs.ifsPrevState != IFS_UP) {
if (!carrier_isup()) {
if (ifchange_deconfig(&cs) < 0)
suicide("%s: can't deconfigure interface settings", __func__);
}
@ -584,8 +568,7 @@ int main(int argc, char *argv[])
get_clientid(&cs, &client_config);
switch (perform_ifup()) {
case 1: cs.ifsPrevState = IFS_UP;
case 0: break;
case 1: case 0: break;
case -3: wait_for_rfkill(); break;
default: suicide("failed to set the interface to up state");
}

1
src/ndhc.h
View File

@ -38,7 +38,6 @@ struct client_state_t {
struct nk_random_state_u32 rnd32_state;
long long leaseStartTime, renewTime, rebindTime;
long long dhcp_wake_ts;
int ifsPrevState;
int ifDeconfig; // Set if the interface has already been deconfigured.
int epollFd, signalFd, listenFd, arpFd, nlFd, rfkillFd;
int nlPortId;

26
src/netlink.c
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@ -43,35 +43,25 @@
#include "nl.h"
#include "state.h"
int nl_event_react(struct client_state_t cs[static 1], int state)
// Returns true if the current interface state is UP.
bool nl_event_carrier_wentup(int state)
{
if (state == cs->ifsPrevState)
return 0;
switch (state) {
case IFS_UP:
cs->ifsPrevState = IFS_UP;
return 1;
log_line("%s: Carrier up.", client_config.interface);
return true;
case IFS_DOWN:
// Interface configured, but no hardware carrier.
cs->ifsPrevState = IFS_DOWN;
log_line("%s: Carrier down.", client_config.interface);
return 0;
return false;
case IFS_SHUT:
// User shut down the interface.
cs->ifsPrevState = IFS_SHUT;
log_line("%s: Interface shut down. Going to sleep.",
client_config.interface);
// XXX: I think this was wrong; instead it should just sleep.
// The lease has not expired just because the user shut down
// the interface...
// set_released(cs);
return 0;
log_line("%s: Interface shut down.", client_config.interface);
return false;
case IFS_REMOVED:
cs->ifsPrevState = IFS_REMOVED;
log_line("Interface removed. Exiting.");
exit(EXIT_SUCCESS);
default: return 0;
default: return false;
}
}

3
src/netlink.h
View File

@ -29,6 +29,7 @@
#ifndef NK_NETLINK_H_
#define NK_NETLINK_H_
#include <stdbool.h>
#include <linux/rtnetlink.h>
#include "state.h"
@ -40,7 +41,7 @@ enum {
IFS_REMOVED
};
int nl_event_react(struct client_state_t cs[static 1], int state);
bool nl_event_carrier_wentup(int state);
int nl_event_get(struct client_state_t cs[static 1]);
int nl_getifdata(void);