system-linux: handle ethtool offload, channels, ring, coalesce and priv flags parameters

.gitignore

@@ -8,3 +8,4 @@ CMakeFiles
 install_manifest.txt
 CMakeLists.txt.user
 netifd.kdev4
+compile_commands.json

device.c

@@ -76,6 +76,11 @@ static const struct blobmsg_policy dev_attrs[__DEV_ATTR_MAX] = {
 	[DEV_ATTR_MASTER] = { .name = "conduit", .type = BLOBMSG_TYPE_STRING },
 	[DEV_ATTR_EEE] = { .name = "eee", .type = BLOBMSG_TYPE_BOOL },
 	[DEV_ATTR_TAGS] = { .name = "tags", .type = BLOBMSG_TYPE_ARRAY },
+	[DEV_ATTR_OFFLOAD] = { .name = "ethtool_offload", .type = BLOBMSG_TYPE_ARRAY },
+	[DEV_ATTR_RING] = { .name = "ethtool_ring", .type = BLOBMSG_TYPE_ARRAY },
+	[DEV_ATTR_COALESCE] = { .name = "ethtool_coalesce", .type = BLOBMSG_TYPE_ARRAY },
+	[DEV_ATTR_CHANNELS] = { .name = "ethtool_channels", .type = BLOBMSG_TYPE_ARRAY },
+	[DEV_ATTR_PRIV] = { .name = "ethtool_priv", .type = BLOBMSG_TYPE_ARRAY },
 };
 
 const struct uci_blob_param_list device_attr_list = {
@@ -590,6 +595,26 @@ device_init_settings(struct device *dev, struct blob_attr **tb)
 	free(dev->tags);
 	dev->tags = cur ? blob_memdup(cur) : NULL;
 
+	cur = tb[DEV_ATTR_OFFLOAD];
+	free(dev->ethtool_offload);
+	dev->ethtool_offload = cur ? blob_memdup(cur) : NULL;
+
+	cur = tb[DEV_ATTR_RING];
+	free(dev->ethtool_ring);
+	dev->ethtool_ring = cur ? blob_memdup(cur) : NULL;
+
+	cur = tb[DEV_ATTR_COALESCE];
+	free(dev->ethtool_coalesce);
+	dev->ethtool_coalesce = cur ? blob_memdup(cur) : NULL;
+
+	cur = tb[DEV_ATTR_CHANNELS];
+	free(dev->ethtool_channels);
+	dev->ethtool_channels = cur ? blob_memdup(cur) : NULL;
+
+	cur = tb[DEV_ATTR_PRIV];
+	free(dev->ethtool_priv);
+	dev->ethtool_priv = cur ? blob_memdup(cur) : NULL;
+
 	device_set_extra_vlans(dev, tb[DEV_ATTR_VLAN]);
 	device_set_disabled(dev, disabled);
 }
@@ -1093,6 +1118,11 @@ device_free(struct device *dev)
 	free(dev->tags);
 	free(dev->config_auth_vlans);
 	free(dev->extra_vlan);
+	free(dev->ethtool_offload);
+	free(dev->ethtool_ring);
+	free(dev->ethtool_coalesce);
+	free(dev->ethtool_channels);
+	free(dev->ethtool_priv);
 	dev->type->free(dev);
 	__devlock--;
 }

device.h

@@ -73,6 +73,11 @@ enum {
 	DEV_ATTR_MASTER,
 	DEV_ATTR_EEE,
 	DEV_ATTR_TAGS,
+	DEV_ATTR_OFFLOAD,
+	DEV_ATTR_RING,
+	DEV_ATTR_COALESCE,
+	DEV_ATTR_CHANNELS,
+	DEV_ATTR_PRIV,
 	__DEV_ATTR_MAX,
 };
 
@@ -252,6 +257,11 @@ struct device {
 	struct blob_attr *config_auth_vlans;
 	struct blob_attr *auth_vlans;
 	struct blob_attr *tags;
+	struct blob_attr *ethtool_offload;
+	struct blob_attr *ethtool_ring;
+	struct blob_attr *ethtool_coalesce;
+	struct blob_attr *ethtool_channels;
+	struct blob_attr *ethtool_priv;
 
 	char ifname[IFNAMSIZ];
 	int ifindex;

examples/ethtool-tunables-network-config.md

@@ -0,0 +1,47 @@
+# Example: Applying ethtool tunables via /etc/config/network
+
+You can specify ethtool flags for supported family (offload, ring, coalesce, channels, priv) in a device section of `/etc/config/network`.
+
+> This doesn't replace existing flags already handled by netifd via ethtool (like `rxpause`, `txpause`, `autoneg`), it only adds support for additional ethtool tunables.
+
+## Example device config
+
+```
+config device
+    option name 'eth1'
+    list offload 'sg on'
+    list offload 'gso on'
+    list offload 'gro on'
+    list offload 'tso off'
+    list offload 'rx_gro_list off'
+    list offload 'rx_udp_gro_forwarding on'
+    list ring 'rx 4096'
+    list ring 'tx 4096'
+    list coalesce 'rx-usecs 50'
+    list coalesce 'tx-frames 128'
+    list channels 'rx 4'
+    list channels 'tx 4'
+    list priv 'my_custom_flag on'
+    option txqueuelen '10000'
+```
+
+## Supported ethtool tunable families
+
+- `list offload` (ethtool -K)
+- `list ring` (ethtool -G)
+- `list coalesce` (ethtool -C)
+- `list channels` (ethtool -L)
+- `list priv` (ethtool --set-priv-flags)
+
+Each list item is a key-value pair, e.g. `list offload 'tso off'`.
+
+## How it works
+
+- When netifd brings up the device, it parses these lists and applies them using the corresponding system_set_ethtool* handler (see `system-linux.c`).
+- All settings are applied via netlink/ethtool, just as in the shell/init script, but natively in C.
+
+## Notes
+
+- You can specify multiple flags per family.
+- If a flag is not supported by the driver, it will be ignored or logged as a warning.
+- For advanced usage, refer to the system_set_ethtool* handlers in `system-linux.c` for details on what is supported.