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Test: etharp_gratuitous #1877

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merged 10 commits into from
Aug 30, 2019
Merged

Test: etharp_gratuitous #1877

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5f376de
test: etharp_gratuitous
mcspr Aug 27, 2019
142a36b
proper checks before calling etharp_gratuitous, move includes
mcspr Aug 29, 2019
7199d24
disable at runtime
mcspr Aug 29, 2019
63db3b0
Merge remote-tracking branch 'origin/dev' into etharp_gratuitous
mcspr Aug 29, 2019
732cc7e
ms values
mcspr Aug 29, 2019
40da164
reload
mcspr Aug 29, 2019
4c4a040
debug
mcspr Aug 29, 2019
3fdf59e
reword
mcspr Aug 29, 2019
b97c6ab
filter by ifnum instead of checking for AP mode
mcspr Aug 29, 2019
7264f7e
drop station_if check
mcspr Aug 30, 2019
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20 changes: 20 additions & 0 deletions code/espurna/config/general.h
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Original file line number Diff line number Diff line change
Expand Up @@ -554,6 +554,26 @@
#define WIFI_PROPAGATION_CONST 4 // This is typically something between 2.7 to 4.3 (free space is 2)
#endif

// ref: https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/kconfig.html#config-lwip-esp-gratuitous-arp
// ref: https://github.com/xoseperez/espurna/pull/1877#issuecomment-525612546
//
// Help solve compatibility issues with some routers.
// If the ARP table of the AP is old, and the AP doesn't send ARP request to update it's ARP table,
// this will lead to the STA sending IP packet fail. Thus we send gratuitous ARP periodically to let AP update it's ARP table.
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Strictly speaking, it is not the sending of an packet that fails, but receiving.
The other hosts in the network may no longer know how to retrieve what MAC address to use as destination when sending a packet to some IP-address. Also the other components on the network, like switch or AP may have the MAC address removed from their tables and thus no longer be able to route the packet to the correct port.

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The wording is weird, true... that was a blatant c/p from the esp-lwip Kconfig entry. Reworded to mention ARP tables.


#ifndef WIFI_GRATUITOUS_ARP_SUPPORT
#define WIFI_GRATUITOUS_ARP_SUPPORT 1
#endif

// Interval is randomized on each boot in range from ..._MIN to ..._MAX (ms)
#ifndef WIFI_GRATUITOUS_ARP_INTERVAL_MIN
#define WIFI_GRATUITOUS_ARP_INTERVAL_MIN 15000
#endif

#ifndef WIFI_GRATUITOUS_ARP_INTERVAL_MAX
#define WIFI_GRATUITOUS_ARP_INTERVAL_MAX 30000
#endif

// -----------------------------------------------------------------------------
// WEB
// -----------------------------------------------------------------------------
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6 changes: 6 additions & 0 deletions code/espurna/config/prototypes.h
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Expand Up @@ -349,6 +349,12 @@ using wifi_callback_f = std::function<void(justwifi_messages_t code, char * para
void wifiRegister(wifi_callback_f callback);
bool wifiConnected();

#if LWIP_VERSION_MAJOR == 1
#include <netif/etharp.h>
#else // LWIP_VERSION_MAJOR >= 2
#include <lwip/etharp.h>
#endif

// -----------------------------------------------------------------------------
// THERMOSTAT
// -----------------------------------------------------------------------------
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61 changes: 61 additions & 0 deletions code/espurna/wifi.ino
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Expand Up @@ -15,6 +15,11 @@ bool _wifi_smartconfig_running = false;
bool _wifi_smartconfig_initial = false;
uint8_t _wifi_ap_mode = WIFI_AP_FALLBACK;

#if WIFI_GRATUITOUS_ARP_SUPPORT
unsigned long _wifi_gratuitous_arp_interval = 0;
unsigned long _wifi_gratuitous_arp_last = 0;
#endif

// -----------------------------------------------------------------------------
// PRIVATE
// -----------------------------------------------------------------------------
Expand Down Expand Up @@ -84,6 +89,14 @@ void _wifiConfigure() {
sleep_mode = constrain(sleep_mode, 0, 2);

WiFi.setSleepMode(static_cast<WiFiSleepType_t>(sleep_mode));

#if WIFI_GRATUITOUS_ARP_SUPPORT
_wifi_gratuitous_arp_last = millis();
_wifi_gratuitous_arp_interval = getSetting("wifiGarpIntvl", secureRandom(
WIFI_GRATUITOUS_ARP_INTERVAL_MIN, WIFI_GRATUITOUS_ARP_INTERVAL_MAX
)).toInt();
#endif

}

void _wifiScan(uint32_t client_id = 0) {
Expand Down Expand Up @@ -491,6 +504,47 @@ void _wifiWebSocketOnAction(uint32_t client_id, const char * action, JsonObject&

#endif

// -----------------------------------------------------------------------------
// SUPPORT
// -----------------------------------------------------------------------------

#if WIFI_GRATUITOUS_ARP_SUPPORT

// ref: lwip src/core/netif.c netif_issue_reports(...)
// ref: esp-lwip/core/ipv4/etharp.c garp_tmr()
// TODO: only for ipv4, need (?) a different method with ipv6
bool _wifiSendGratuitousArp() {

bool result = false;
for (netif* interface = netif_list; interface != nullptr; interface = interface->next) {
if (
(interface->flags & NETIF_FLAG_ETHARP)
&& (interface->hwaddr_len == ETHARP_HWADDR_LEN)
#if LWIP_VERSION_MAJOR != 1
&& (interface->flags & NETIF_FLAG_LINK_UP)
&& (!ip4_addr_isany_val(*netif_ip4_addr(interface)))
#else
&& (!ip_addr_isany(&interface->ip_addr))
#endif
&& (interface->flags & NETIF_FLAG_UP)
) {
etharp_gratuitous(interface);
result = true;
}
}

return result;
}

void _wifiSendGratuitousArp(unsigned long interval) {
if (millis() - _wifi_gratuitous_arp_last > interval) {
_wifi_gratuitous_arp_last = millis();
_wifiSendGratuitousArp();
}
}

#endif // WIFI_GRATUITOUS_ARP_SUPPORT

// -----------------------------------------------------------------------------
// INFO
// -----------------------------------------------------------------------------
Expand Down Expand Up @@ -685,4 +739,11 @@ void wifiLoop() {
_wifiCheckAP();
}

#if WIFI_GRATUITOUS_ARP_SUPPORT
// Only send out gra arp when in STA mode
if (_wifi_gratuitous_arp_interval && ((WiFi.getMode() & WIFI_AP) == 0)) {
_wifiSendGratuitousArp(_wifi_gratuitous_arp_interval);
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With STA+AP mode the WiFi radio is always on, which makes it less likely ARP requests may be missed.
But it may still be useful to send it if you get a (new) IP address.
Just make sure to only send it to the STATION_IF if you want to distinguish this.

N.B. the AP and STA use different MAC addresses, so it should be no problem to send out Gratuitous ARP to the AP interface. (as long as you're sending the right IP of course :) )

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This part is copied from the idf, basically trying to emulate GARP flag that they check. No flag here, so STATION_IF seems like a solution.

}
#endif

}