From 39f3f5b2d95fe1e393954623b0943189441df187 Mon Sep 17 00:00:00 2001
From: Joseph Henry <joseph.henry@zerotier.com>
Date: Wed, 11 Jan 2023 20:12:15 -0800
Subject: [PATCH] User-configurable physical MTU for individual links
This patch allows users to specify the physical layer MTU for individual links
when in multipath mode. For example:
{
"settings":
{
"defaultBondingPolicy": "custom-balance-xor",
"policies":
{
"custom-balance-xor":
{
"basePolicy": "balance-xor",
"failoverInterval": 5000,
"links": {
"weird_5g_link": { "mtu": 1300 },
"enp5s0": { "mtu": 1400 }
}
}
}
}
}
---
node/Bond.cpp | 3 ++-
node/Bond.hpp | 16 +++++++++++++++-
node/Path.hpp | 8 ++++++++
node/Switch.cpp | 11 ++++++++---
node/Switch.hpp | 2 +-
service/OneService.cpp | 3 ++-
6 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/node/Bond.cpp b/node/Bond.cpp
index dc17e6bee..8edd7e297 100644
--- a/node/Bond.cpp
+++ b/node/Bond.cpp
@@ -184,7 +184,7 @@ SharedPtr<Link> Bond::getLinkBySocket(const std::string& policyAlias, uint64_t l
auto search = _interfaceToLinkMap[policyAlias].find(ifnameStr);
if (search == _interfaceToLinkMap[policyAlias].end()) {
if (createIfNeeded) {
- SharedPtr<Link> s = new Link(ifnameStr, 0, 0, true, ZT_BOND_SLAVE_MODE_PRIMARY, "");
+ SharedPtr<Link> s = new Link(ifnameStr, 0, 0, 0, true, ZT_BOND_SLAVE_MODE_PRIMARY, "");
_interfaceToLinkMap[policyAlias].insert(std::pair<std::string, SharedPtr<Link> >(ifnameStr, s));
return s;
}
@@ -1253,6 +1253,7 @@ void Bond::estimatePathQuality(int64_t now)
if (link) {
int linkSpeed = link->capacity();
_paths[i].p->_givenLinkSpeed = linkSpeed;
+ _paths[i].p->_mtu = link->mtu();
maxObservedLinkCap = linkSpeed > maxObservedLinkCap ? linkSpeed : maxObservedLinkCap;
}
}
diff --git a/node/Bond.hpp b/node/Bond.hpp
index 3419c8cfe..389b970e9 100644
--- a/node/Bond.hpp
+++ b/node/Bond.hpp
@@ -122,9 +122,10 @@ class Link {
* @param mode
* @param failoverToLinkStr
*/
- Link(std::string ifnameStr, uint8_t ipvPref, uint32_t capacity, bool enabled, uint8_t mode, std::string failoverToLinkStr)
+ Link(std::string ifnameStr, uint8_t ipvPref, uint16_t mtu, uint32_t capacity, bool enabled, uint8_t mode, std::string failoverToLinkStr)
: _ifnameStr(ifnameStr)
, _ipvPref(ipvPref)
+ , _mtu(mtu)
, _capacity(capacity)
, _relativeCapacity(0.0)
, _enabled(enabled)
@@ -226,6 +227,14 @@ class Link {
return _ipvPref;
}
+ /**
+ * @return The MTU for this link (as specified by the user.)
+ */
+ inline uint16_t mtu()
+ {
+ return _mtu;
+ }
+
/**
* @return The mode (e.g. primary/spare) for this link (as specified by the user.)
*/
@@ -260,6 +269,11 @@ class Link {
*/
uint8_t _ipvPref;
+ /**
+ * The physical-layer MTU for this link
+ */
+ uint16_t _mtu;
+
/**
* User-specified capacity of this link
*/
diff --git a/node/Path.hpp b/node/Path.hpp
index 8304f27d8..eb268695d 100644
--- a/node/Path.hpp
+++ b/node/Path.hpp
@@ -92,6 +92,7 @@ public:
_valid(true),
_eligible(false),
_bonded(false),
+ _mtu(0),
_givenLinkSpeed(0),
_relativeQuality(0),
_latency(0xffff),
@@ -112,6 +113,7 @@ public:
_valid(true),
_eligible(false),
_bonded(false),
+ _mtu(0),
_givenLinkSpeed(0),
_relativeQuality(0),
_latency(0xffff),
@@ -334,6 +336,11 @@ public:
*/
inline unsigned int bonded() const { return _bonded; }
+ /**
+ * @return Whether the user-specified MTU for this path (determined by MTU for parent link)
+ */
+ inline unsigned int mtu() const { return _mtu; }
+
/**
* @return Given link capacity as reported by the bonding layer
*/
@@ -370,6 +377,7 @@ private:
volatile bool _valid;
volatile bool _eligible;
volatile bool _bonded;
+ volatile uint16_t _mtu;
volatile uint32_t _givenLinkSpeed;
volatile float _relativeQuality;
diff --git a/node/Switch.cpp b/node/Switch.cpp
index ae870a278..9a81e532e 100644
--- a/node/Switch.cpp
+++ b/node/Switch.cpp
@@ -1009,7 +1009,8 @@ bool Switch::_trySend(void *tPtr,Packet &packet,bool encrypt,int32_t flowId)
Mutex::Lock _l(peer->_paths_m);
for(int i=0;i<ZT_MAX_PEER_NETWORK_PATHS;++i) {
if (peer->_paths[i].p && peer->_paths[i].p->alive(now)) {
- _sendViaSpecificPath(tPtr,peer,peer->_paths[i].p,now,packet,encrypt,flowId);
+ uint16_t userSpecifiedMtu = peer->_paths[i].p->mtu();
+ _sendViaSpecificPath(tPtr,peer,peer->_paths[i].p, userSpecifiedMtu,now,packet,encrypt,flowId);
}
}
return true;
@@ -1025,7 +1026,8 @@ bool Switch::_trySend(void *tPtr,Packet &packet,bool encrypt,int32_t flowId)
}
}
if (viaPath) {
- _sendViaSpecificPath(tPtr,peer,viaPath,now,packet,encrypt,flowId);
+ uint16_t userSpecifiedMtu = viaPath->mtu();
+ _sendViaSpecificPath(tPtr,peer,viaPath,userSpecifiedMtu,now,packet,encrypt,flowId);
return true;
}
}
@@ -1033,12 +1035,15 @@ bool Switch::_trySend(void *tPtr,Packet &packet,bool encrypt,int32_t flowId)
return false;
}
-void Switch::_sendViaSpecificPath(void *tPtr,SharedPtr<Peer> peer,SharedPtr<Path> viaPath,int64_t now,Packet &packet,bool encrypt,int32_t flowId)
+void Switch::_sendViaSpecificPath(void *tPtr,SharedPtr<Peer> peer,SharedPtr<Path> viaPath,uint16_t userSpecifiedMtu, int64_t now,Packet &packet,bool encrypt,int32_t flowId)
{
unsigned int mtu = ZT_DEFAULT_PHYSMTU;
uint64_t trustedPathId = 0;
RR->topology->getOutboundPathInfo(viaPath->address(),mtu,trustedPathId);
+ if (userSpecifiedMtu > 0) {
+ mtu = userSpecifiedMtu;
+ }
unsigned int chunkSize = std::min(packet.size(),mtu);
packet.setFragmented(chunkSize < packet.size());
diff --git a/node/Switch.hpp b/node/Switch.hpp
index 4ca1c0e50..9bb1fbeaf 100644
--- a/node/Switch.hpp
+++ b/node/Switch.hpp
@@ -207,7 +207,7 @@ public:
private:
bool _shouldUnite(const int64_t now,const Address &source,const Address &destination);
bool _trySend(void *tPtr,Packet &packet,bool encrypt,int32_t flowId = ZT_QOS_NO_FLOW); // packet is modified if return is true
- void _sendViaSpecificPath(void *tPtr,SharedPtr<Peer> peer,SharedPtr<Path> viaPath,int64_t now,Packet &packet,bool encrypt,int32_t flowId);
+ void _sendViaSpecificPath(void *tPtr,SharedPtr<Peer> peer,SharedPtr<Path> viaPath,uint16_t userSpecifiedMtu, int64_t now,Packet &packet,bool encrypt,int32_t flowId);
const RuntimeEnvironment *const RR;
int64_t _lastBeaconResponse;
diff --git a/service/OneService.cpp b/service/OneService.cpp
index bbd48c7aa..429ae20e4 100644
--- a/service/OneService.cpp
+++ b/service/OneService.cpp
@@ -2075,6 +2075,7 @@ public:
bool enabled = OSUtils::jsonInt(link["enabled"],true);
uint32_t capacity = OSUtils::jsonInt(link["capacity"],0);
uint8_t ipvPref = OSUtils::jsonInt(link["ipvPref"],0);
+ uint16_t mtu = OSUtils::jsonInt(link["mtu"],0);
std::string failoverToStr(OSUtils::jsonString(link["failoverTo"],""));
// Mode
std::string linkModeStr(OSUtils::jsonString(link["mode"],"spare"));
@@ -2091,7 +2092,7 @@ public:
failoverToStr = "";
enabled = false;
}
- _node->bondController()->addCustomLink(customPolicyStr, new Link(linkNameStr,ipvPref,capacity,enabled,linkMode,failoverToStr));
+ _node->bondController()->addCustomLink(customPolicyStr, new Link(linkNameStr,ipvPref,mtu,capacity,enabled,linkMode,failoverToStr));
}
std::string linkSelectMethodStr(OSUtils::jsonString(customPolicy["activeReselect"],"optimize"));
if (linkSelectMethodStr == "always") {