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Add error handling for un-notified carrier downs when sending packets.

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If a packet send failed because the carrier went down without a
netlink notification, then assume the hardware carrier was lost while
the machine was suspended (eg, ethernet cable pulled during suspend).

Simulate a netlink carrier down event and freeze the dhcp state
machine until a netlink carrier up event is received.

The ARP code is not yet handling this issue everywhere, but the
window of opportunity for it to happen there is much shorter.
This commit is contained in:
Nicholas J. Kain 2015-02-14 05:20:04 -05:00
parent d0d8bcf3ff
commit b6b778831c
3 changed files with 92 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
src/arp.c
View File

@ -45,6 +45,7 @@
#include "options.h"
#include "leasefile.h"
#include "sockd.h"
#include "netlink.h"
#define ARP_MSG_SIZE 0x2a
#define ARP_RETRANS_DELAY 5000 // ms
@ -246,6 +247,7 @@ static void arp_reopen_fd(struct client_state_t cs[static 1])
static int arp_send(struct client_state_t cs[static 1],
struct arpMsg arp[static 1])
{
int ret = -1;
struct sockaddr_ll addr = {
.sll_family = AF_PACKET,
.sll_ifindex = client_config.ifindex,
@ -256,27 +258,27 @@ static int arp_send(struct client_state_t cs[static 1],
if (cs->arpFd < 0) {
log_warning("%s: arp: Send attempted when no ARP fd is open.",
client_config.interface);
return -1;
return ret;
}
ssize_t r;
if (!check_carrier(cs->arpFd)) {
log_error("%s: (%s) carrier down; sendto would fail",
client_config.interface, __func__);
ret = -99;
goto carrier_down;
}
r = safe_sendto(cs->arpFd, (const char *)arp, sizeof *arp, 0,
ret = safe_sendto(cs->arpFd, (const char *)arp, sizeof *arp, 0,
(struct sockaddr *)&addr, sizeof addr);
if (r < 0 || (size_t)r != sizeof *arp) {
if (r < 0)
if (ret < 0 || (size_t)ret != sizeof *arp) {
if (ret < 0)
log_error("%s: (%s) sendto failed: %s",
client_config.interface, __func__, strerror(errno));
else
log_error("%s: (%s) sendto short write: %z < %zu",
client_config.interface, __func__, r, sizeof *arp);
log_error("%s: (%s) sendto short write: %d < %zu",
client_config.interface, __func__, ret, sizeof *arp);
carrier_down:
arp_reopen_fd(cs);
return -1;
return ret;
}
return 0;
}
@ -299,8 +301,9 @@ static int arp_ping(struct client_state_t cs[static 1], uint32_t test_ip)
BASE_ARPMSG();
memcpy(arp.sip4, &cs->clientAddr, sizeof cs->clientAddr);
memcpy(arp.dip4, &test_ip, sizeof test_ip);
if (arp_send(cs, &arp) < 0)
return -1;
int r = arp_send(cs, &arp);
if (r < 0)
return r;
garp.send_stats[ASEND_GW_PING].count++;
garp.send_stats[ASEND_GW_PING].ts = curms();
return 0;
@ -314,8 +317,9 @@ static int arp_ip_anon_ping(struct client_state_t cs[static 1],
memcpy(arp.dip4, &test_ip, sizeof test_ip);
log_line("%s: arp: Probing for hosts that may conflict with our lease...",
client_config.interface);
if (arp_send(cs, &arp) < 0)
return -1;
int r = arp_send(cs, &arp);
if (r < 0)
return r;
garp.send_stats[ASEND_COLLISION_CHECK].count++;
garp.send_stats[ASEND_COLLISION_CHECK].ts = curms();
return 0;
@ -326,8 +330,9 @@ static int arp_announcement(struct client_state_t cs[static 1])
BASE_ARPMSG();
memcpy(arp.sip4, &cs->clientAddr, 4);
memcpy(arp.dip4, &cs->clientAddr, 4);
if (arp_send(cs, &arp) < 0)
return -1;
int r = arp_send(cs, &arp);
if (r < 0)
return r;
garp.send_stats[ASEND_ANNOUNCE].count++;
garp.send_stats[ASEND_ANNOUNCE].ts = curms();
return 0;
@ -404,7 +409,18 @@ static void arp_failed(struct client_state_t cs[static 1])
{
log_line("%s: arp: Offered address is in use. Declining.",
client_config.interface);
send_decline(cs, garp.dhcp_packet.yiaddr);
int r = send_decline(cs, garp.dhcp_packet.yiaddr);
if (r < 0) {
log_warning("%s: Failed to send a decline notice packet.",
client_config.interface);
if (r == -99) {
// Carrier went down while suspended.
cs->ifsPrevState = IFS_DOWN;
ifnocarrier_action(cs);
garp.wake_ts[AS_COLLISION_CHECK] = -1;
return;
}
}
garp.wake_ts[AS_COLLISION_CHECK] = -1;
reinit_selecting(cs, garp.total_conflicts < MAX_CONFLICTS ?
0 : RATE_LIMIT_INTERVAL);

2
src/dhcp.c
View File

@ -111,6 +111,7 @@ static ssize_t send_dhcp_unicast(struct client_state_t cs[static 1],
if (!check_carrier(fd)) {
log_error("%s: (%s) carrier down; write would fail",
client_config.interface, __func__);
ret = -99;
goto out_fd;
}
ret = safe_write(fd, (const char *)payload, payload_len);
@ -304,6 +305,7 @@ static ssize_t send_dhcp_raw(struct dhcpmsg payload[static 1])
if (!check_carrier(fd)) {
log_error("%s: (%s) carrier down; sendto would fail",
client_config.interface, __func__);
ret = -99;
goto carrier_down;
}
ret = safe_sendto(fd, (const char *)&iudmsg, iud_len, 0,

89
src/state.c
View File

@ -40,6 +40,16 @@
#include "options.h"
#include "ndhc.h"
#include "sys.h"
#include "netlink.h"
// Simulates netlink carrier down event if carrier went down while suspended.
#define SUSPEND_IF_NOCARRIER() \
if (r == -99) { \
cs->ifsPrevState = IFS_DOWN; \
ifnocarrier_action(cs); \
dhcp_wake_ts = -1; \
return; \
}
static void selecting_packet(struct client_state_t cs[static 1],
struct dhcpmsg packet[static 1],
@ -133,14 +143,18 @@ static void set_released(struct client_state_t cs[static 1])
static void requesting_timeout(struct client_state_t cs[static 1],
long long nowts)
{
if (num_dhcp_requests < 5) {
if (send_selecting(cs) < 0)
log_warning("%s: Failed to send a selecting request packet.",
client_config.interface);
dhcp_wake_ts = nowts + delay_timeout(cs, num_dhcp_requests);
num_dhcp_requests++;
} else
if (num_dhcp_requests >= 5) {
reinit_selecting(cs, 0);
return;
}
int r = send_selecting(cs);
if (r < 0) {
log_warning("%s: Failed to send a selecting request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
dhcp_wake_ts = nowts + delay_timeout(cs, num_dhcp_requests);
num_dhcp_requests++;
}
// Triggered when the lease has been held for a significant fraction of its
@ -167,19 +181,22 @@ static void renewing_timeout(struct client_state_t cs[static 1],
long long nowts)
{
long long rbt = cs->leaseStartTime + cs->rebindTime * 1000;
if (nowts < rbt) {
if (rbt - nowts < 30000) {
dhcp_wake_ts = rbt;
return;
}
if (send_renew(cs) < 0)
log_warning("%s: Failed to send a renew request packet.",
client_config.interface);
dhcp_wake_ts = nowts + ((rbt - nowts) / 2);
} else {
if (nowts >= rbt) {
cs->dhcpState = DS_REBINDING;
rebinding_timeout(cs, nowts);
return;
}
if (rbt - nowts < 30000) {
dhcp_wake_ts = rbt;
return;
}
int r = send_renew(cs);
if (r < 0) {
log_warning("%s: Failed to send a renew request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
dhcp_wake_ts = nowts + ((rbt - nowts) / 2);
}
// Triggered when a DHCP rebind request has been sent and no reply has been
@ -190,20 +207,23 @@ static void rebinding_timeout(struct client_state_t cs[static 1],
long long nowts)
{
long long elt = cs->leaseStartTime + cs->lease * 1000;
if (nowts < elt) {
if (elt - nowts < 30000) {
dhcp_wake_ts = elt;
return;
}
if (send_rebind(cs) < 0)
log_warning("%s: Failed to send a rebind request packet.",
client_config.interface);
dhcp_wake_ts = nowts + ((elt - nowts) / 2);
} else {
if (nowts >= elt) {
log_line("%s: Lease expired. Searching for a new lease...",
client_config.interface);
reinit_selecting(cs, 0);
return;
}
if (elt - nowts < 30000) {
dhcp_wake_ts = elt;
return;
}
int r = send_rebind(cs);
if (r < 0) {
log_warning("%s: Failed to send a rebind request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
dhcp_wake_ts = nowts + ((elt - nowts) / 2);
}
static void released_timeout(struct client_state_t cs[static 1],
@ -346,9 +366,12 @@ static void selecting_timeout(struct client_state_t cs[static 1],
}
if (num_dhcp_requests == 0)
cs->xid = nk_random_u32(&cs->rnd32_state);
if (send_discover(cs) < 0)
int r = send_discover(cs);
if (r < 0) {
log_warning("%s: Failed to send a discover request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
dhcp_wake_ts = nowts + delay_timeout(cs, num_dhcp_requests);
num_dhcp_requests++;
}
@ -363,9 +386,12 @@ static void xmit_release(struct client_state_t cs[static 1])
svrbuf, sizeof svrbuf);
log_line("%s: Unicasting a release of %s to %s.", client_config.interface,
clibuf, svrbuf);
if (send_release(cs) < 0)
int r = send_release(cs);
if (r < 0) {
log_warning("%s: Failed to send a release request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
print_release(cs);
}
@ -382,9 +408,12 @@ static void frenew(struct client_state_t cs[static 1])
log_line("%s: Forcing a DHCP renew...", client_config.interface);
cs->dhcpState = DS_RENEWING;
start_dhcp_listen(cs);
if (send_renew(cs) < 0)
int r = send_renew(cs);
if (r < 0) {
log_warning("%s: Failed to send a renew request packet.",
client_config.interface);
SUSPEND_IF_NOCARRIER();
}
} else if (cs->dhcpState == DS_RELEASED)
reinit_selecting(cs, 0);
}