From d9369f5df426a6d8c5c45912879bd4949b818daf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgraber@stgraber.org>
Date: Mon, 11 Nov 2024 15:08:36 -0500
Subject: [PATCH 1/2] internal/linux: Add NetlinkInterfaces
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Stéphane Graber <stgraber@stgraber.org>
Sponsored-by: https://webdock.io
---
 internal/linux/netlink.go | 99 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 internal/linux/netlink.go

diff --git a/internal/linux/netlink.go b/internal/linux/netlink.go
new file mode 100644
index 00000000000..0c79defe599
--- /dev/null
+++ b/internal/linux/netlink.go
@@ -0,0 +1,99 @@
+//go:build linux
+
+package linux
+
+import (
+	"fmt"
+	"net"
+	"syscall"
+	"unsafe"
+)
+
+// NetlinkInterface returns a net.Interface extended to also contain its addresses.
+type NetlinkInterface struct {
+	net.Interface
+
+	Addresses []net.Addr
+}
+
+// NetlinkInterfaces performs a RTM_GETADDR call to get both.
+func NetlinkInterfaces() ([]NetlinkInterface, error) {
+	// Grab the interface list.
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil, err
+	}
+
+	// Initialize result slice.
+	netlinkIfaces := make([]NetlinkInterface, 0, len(ifaces))
+	for _, iface := range ifaces {
+		netlinkIfaces = append(netlinkIfaces, NetlinkInterface{iface, make([]net.Addr, 0)})
+	}
+
+	// Turn it into a map.
+	ifaceMap := make(map[int]*NetlinkInterface, len(ifaces))
+	for k, v := range netlinkIfaces {
+		ifaceMap[v.Index] = &netlinkIfaces[k] //nolint:typecheck
+	}
+
+	// Make the netlink call.
+	rib, err := syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_UNSPEC)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to query RTM_GETADDR: %v", err)
+	}
+
+	messages, err := syscall.ParseNetlinkMessage(rib)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to parse RTM_GETADDR: %v", err)
+	}
+
+	for _, m := range messages {
+		if m.Header.Type == syscall.RTM_NEWADDR {
+			addrMessage := (*syscall.IfAddrmsg)(unsafe.Pointer(&m.Data[0]))
+
+			addrAttrs, err := syscall.ParseNetlinkRouteAttr(&m)
+			if err != nil {
+				return nil, fmt.Errorf("Failed to parse route attribute: %v", err)
+			}
+
+			ifi, ok := ifaceMap[int(addrMessage.Index)]
+			if ok {
+				ifi.Addresses = append(ifi.Addresses, newAddr(addrMessage, addrAttrs))
+			}
+		}
+	}
+
+	return netlinkIfaces, nil
+}
+
+// Variation of function of the same name from within Go source.
+func newAddr(ifam *syscall.IfAddrmsg, attrs []syscall.NetlinkRouteAttr) net.Addr {
+	var ipPointToPoint bool
+
+	// Seems like we need to make sure whether the IP interface
+	// stack consists of IP point-to-point numbered or unnumbered
+	// addressing.
+	for _, a := range attrs {
+		if a.Attr.Type == syscall.IFA_LOCAL {
+			ipPointToPoint = true
+			break
+		}
+	}
+
+	for _, a := range attrs {
+		if ipPointToPoint && a.Attr.Type == syscall.IFA_ADDRESS {
+			continue
+		}
+
+		switch ifam.Family {
+		case syscall.AF_INET:
+			return &net.IPNet{IP: net.IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3]), Mask: net.CIDRMask(int(ifam.Prefixlen), 8*net.IPv4len)}
+		case syscall.AF_INET6:
+			ifa := &net.IPNet{IP: make(net.IP, net.IPv6len), Mask: net.CIDRMask(int(ifam.Prefixlen), 8*net.IPv6len)}
+			copy(ifa.IP, a.Value[:])
+			return ifa
+		}
+	}
+
+	return nil
+}

From 94cc8d6d3d6f0edbb09b8adeadafefaceee32f03 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgraber@stgraber.org>
Date: Mon, 11 Nov 2024 15:18:33 -0500
Subject: [PATCH 2/2] incus-agent: Use NetlinkInterfaces
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fetching addresses for a single interface in Go is terribly slow, use a
bulk query method.

Signed-off-by: Stéphane Graber <stgraber@stgraber.org>
Sponsored-by: https://webdock.io
---
 cmd/incus-agent/state.go | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/cmd/incus-agent/state.go b/cmd/incus-agent/state.go
index 9b0218e38ee..189d6274a10 100644
--- a/cmd/incus-agent/state.go
+++ b/cmd/incus-agent/state.go
@@ -123,7 +123,7 @@ func memoryState() api.InstanceStateMemory {
 func networkState() map[string]api.InstanceStateNetwork {
 	result := map[string]api.InstanceStateNetwork{}
 
-	ifs, err := net.Interfaces()
+	ifs, err := linux.NetlinkInterfaces()
 	if err != nil {
 		logger.Errorf("Failed to retrieve network interfaces: %v", err)
 		return result
@@ -180,9 +180,7 @@ func networkState() map[string]api.InstanceStateNetwork {
 		}
 
 		// Addresses
-		addrs, _ := iface.Addrs()
-
-		for _, addr := range addrs {
+		for _, addr := range iface.Addresses {
 			addressFields := strings.Split(addr.String(), "/")
 
 			networkAddress := api.InstanceStateNetworkAddress{