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	This change actually defines the (initial) metadata layout
that should be used by AF_XDP userspace (xsk_tx_metadata).
The first field is flags which requests appropriate offloads,
followed by the offload-specific fields. The supported per-device
offloads are exported via netlink (new xsk-flags).
The offloads themselves are still implemented in a bit of a
framework-y fashion that's left from my initial kfunc attempt.
I'm introducing new xsk_tx_metadata_ops which drivers are
supposed to implement. The drivers are also supposed
to call xsk_tx_metadata_request/xsk_tx_metadata_complete in
the right places. Since xsk_tx_metadata_{request,_complete}
are static inline, we don't incur any extra overhead doing
indirect calls.
The benefit of this scheme is as follows:
- keeps all metadata layout parsing away from driver code
- makes it easy to grep and see which drivers implement what
- don't need any extra flags to maintain to keep track of what
  offloads are implemented; if the callback is implemented - the offload
  is supported (used by netlink reporting code)
Two offloads are defined right now:
1. XDP_TXMD_FLAGS_CHECKSUM: skb-style csum_start+csum_offset
2. XDP_TXMD_FLAGS_TIMESTAMP: writes TX timestamp back into metadata
   area upon completion (tx_timestamp field)
XDP_TXMD_FLAGS_TIMESTAMP is also implemented for XDP_COPY mode: it writes
SW timestamp from the skb destructor (note I'm reusing hwtstamps to pass
metadata pointer).
The struct is forward-compatible and can be extended in the future
by appending more fields.
Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20231127190319.1190813-3-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
		
	
			
		
			
				
	
	
		
			244 lines
		
	
	
	
		
			6.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			244 lines
		
	
	
	
		
			6.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
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/* Do not edit directly, auto-generated from: */
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/*	Documentation/netlink/specs/netdev.yaml */
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/* YNL-GEN user source */
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#include <stdlib.h>
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#include <string.h>
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#include "netdev-user.h"
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#include "ynl.h"
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#include <linux/netdev.h>
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#include <libmnl/libmnl.h>
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#include <linux/genetlink.h>
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/* Enums */
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static const char * const netdev_op_strmap[] = {
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	[NETDEV_CMD_DEV_GET] = "dev-get",
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	[NETDEV_CMD_DEV_ADD_NTF] = "dev-add-ntf",
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	[NETDEV_CMD_DEV_DEL_NTF] = "dev-del-ntf",
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	[NETDEV_CMD_DEV_CHANGE_NTF] = "dev-change-ntf",
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};
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const char *netdev_op_str(int op)
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{
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	if (op < 0 || op >= (int)MNL_ARRAY_SIZE(netdev_op_strmap))
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		return NULL;
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	return netdev_op_strmap[op];
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}
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static const char * const netdev_xdp_act_strmap[] = {
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	[0] = "basic",
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	[1] = "redirect",
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	[2] = "ndo-xmit",
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	[3] = "xsk-zerocopy",
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	[4] = "hw-offload",
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	[5] = "rx-sg",
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	[6] = "ndo-xmit-sg",
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};
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const char *netdev_xdp_act_str(enum netdev_xdp_act value)
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{
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	value = ffs(value) - 1;
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	if (value < 0 || value >= (int)MNL_ARRAY_SIZE(netdev_xdp_act_strmap))
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		return NULL;
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	return netdev_xdp_act_strmap[value];
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}
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static const char * const netdev_xdp_rx_metadata_strmap[] = {
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	[0] = "timestamp",
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	[1] = "hash",
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};
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const char *netdev_xdp_rx_metadata_str(enum netdev_xdp_rx_metadata value)
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{
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	value = ffs(value) - 1;
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	if (value < 0 || value >= (int)MNL_ARRAY_SIZE(netdev_xdp_rx_metadata_strmap))
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		return NULL;
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	return netdev_xdp_rx_metadata_strmap[value];
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}
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static const char * const netdev_xsk_flags_strmap[] = {
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	[0] = "tx-timestamp",
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	[1] = "tx-checksum",
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};
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const char *netdev_xsk_flags_str(enum netdev_xsk_flags value)
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{
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	value = ffs(value) - 1;
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	if (value < 0 || value >= (int)MNL_ARRAY_SIZE(netdev_xsk_flags_strmap))
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		return NULL;
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	return netdev_xsk_flags_strmap[value];
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}
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/* Policies */
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struct ynl_policy_attr netdev_dev_policy[NETDEV_A_DEV_MAX + 1] = {
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	[NETDEV_A_DEV_IFINDEX] = { .name = "ifindex", .type = YNL_PT_U32, },
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	[NETDEV_A_DEV_PAD] = { .name = "pad", .type = YNL_PT_IGNORE, },
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	[NETDEV_A_DEV_XDP_FEATURES] = { .name = "xdp-features", .type = YNL_PT_U64, },
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	[NETDEV_A_DEV_XDP_ZC_MAX_SEGS] = { .name = "xdp-zc-max-segs", .type = YNL_PT_U32, },
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	[NETDEV_A_DEV_XDP_RX_METADATA_FEATURES] = { .name = "xdp-rx-metadata-features", .type = YNL_PT_U64, },
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	[NETDEV_A_DEV_XSK_FEATURES] = { .name = "xsk-features", .type = YNL_PT_U64, },
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};
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struct ynl_policy_nest netdev_dev_nest = {
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	.max_attr = NETDEV_A_DEV_MAX,
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	.table = netdev_dev_policy,
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};
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/* Common nested types */
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/* ============== NETDEV_CMD_DEV_GET ============== */
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/* NETDEV_CMD_DEV_GET - do */
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void netdev_dev_get_req_free(struct netdev_dev_get_req *req)
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{
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	free(req);
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}
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void netdev_dev_get_rsp_free(struct netdev_dev_get_rsp *rsp)
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{
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	free(rsp);
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}
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int netdev_dev_get_rsp_parse(const struct nlmsghdr *nlh, void *data)
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{
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	struct ynl_parse_arg *yarg = data;
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	struct netdev_dev_get_rsp *dst;
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	const struct nlattr *attr;
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	dst = yarg->data;
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	mnl_attr_for_each(attr, nlh, sizeof(struct genlmsghdr)) {
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		unsigned int type = mnl_attr_get_type(attr);
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		if (type == NETDEV_A_DEV_IFINDEX) {
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			if (ynl_attr_validate(yarg, attr))
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				return MNL_CB_ERROR;
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			dst->_present.ifindex = 1;
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			dst->ifindex = mnl_attr_get_u32(attr);
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		} else if (type == NETDEV_A_DEV_XDP_FEATURES) {
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			if (ynl_attr_validate(yarg, attr))
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				return MNL_CB_ERROR;
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			dst->_present.xdp_features = 1;
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			dst->xdp_features = mnl_attr_get_u64(attr);
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		} else if (type == NETDEV_A_DEV_XDP_ZC_MAX_SEGS) {
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			if (ynl_attr_validate(yarg, attr))
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				return MNL_CB_ERROR;
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			dst->_present.xdp_zc_max_segs = 1;
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			dst->xdp_zc_max_segs = mnl_attr_get_u32(attr);
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		} else if (type == NETDEV_A_DEV_XDP_RX_METADATA_FEATURES) {
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			if (ynl_attr_validate(yarg, attr))
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				return MNL_CB_ERROR;
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			dst->_present.xdp_rx_metadata_features = 1;
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			dst->xdp_rx_metadata_features = mnl_attr_get_u64(attr);
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		} else if (type == NETDEV_A_DEV_XSK_FEATURES) {
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			if (ynl_attr_validate(yarg, attr))
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				return MNL_CB_ERROR;
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			dst->_present.xsk_features = 1;
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			dst->xsk_features = mnl_attr_get_u64(attr);
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		}
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	}
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	return MNL_CB_OK;
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}
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struct netdev_dev_get_rsp *
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netdev_dev_get(struct ynl_sock *ys, struct netdev_dev_get_req *req)
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{
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	struct ynl_req_state yrs = { .yarg = { .ys = ys, }, };
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	struct netdev_dev_get_rsp *rsp;
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	struct nlmsghdr *nlh;
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	int err;
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	nlh = ynl_gemsg_start_req(ys, ys->family_id, NETDEV_CMD_DEV_GET, 1);
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	ys->req_policy = &netdev_dev_nest;
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	yrs.yarg.rsp_policy = &netdev_dev_nest;
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	if (req->_present.ifindex)
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		mnl_attr_put_u32(nlh, NETDEV_A_DEV_IFINDEX, req->ifindex);
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	rsp = calloc(1, sizeof(*rsp));
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	yrs.yarg.data = rsp;
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	yrs.cb = netdev_dev_get_rsp_parse;
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	yrs.rsp_cmd = NETDEV_CMD_DEV_GET;
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	err = ynl_exec(ys, nlh, &yrs);
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	if (err < 0)
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		goto err_free;
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	return rsp;
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err_free:
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	netdev_dev_get_rsp_free(rsp);
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	return NULL;
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}
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/* NETDEV_CMD_DEV_GET - dump */
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void netdev_dev_get_list_free(struct netdev_dev_get_list *rsp)
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{
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	struct netdev_dev_get_list *next = rsp;
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	while ((void *)next != YNL_LIST_END) {
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		rsp = next;
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		next = rsp->next;
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		free(rsp);
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	}
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}
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struct netdev_dev_get_list *netdev_dev_get_dump(struct ynl_sock *ys)
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{
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	struct ynl_dump_state yds = {};
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	struct nlmsghdr *nlh;
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	int err;
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	yds.ys = ys;
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	yds.alloc_sz = sizeof(struct netdev_dev_get_list);
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	yds.cb = netdev_dev_get_rsp_parse;
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	yds.rsp_cmd = NETDEV_CMD_DEV_GET;
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	yds.rsp_policy = &netdev_dev_nest;
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	nlh = ynl_gemsg_start_dump(ys, ys->family_id, NETDEV_CMD_DEV_GET, 1);
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	err = ynl_exec_dump(ys, nlh, &yds);
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	if (err < 0)
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		goto free_list;
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	return yds.first;
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free_list:
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	netdev_dev_get_list_free(yds.first);
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	return NULL;
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}
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/* NETDEV_CMD_DEV_GET - notify */
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void netdev_dev_get_ntf_free(struct netdev_dev_get_ntf *rsp)
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{
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	free(rsp);
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}
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static const struct ynl_ntf_info netdev_ntf_info[] =  {
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	[NETDEV_CMD_DEV_ADD_NTF] =  {
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		.alloc_sz	= sizeof(struct netdev_dev_get_ntf),
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		.cb		= netdev_dev_get_rsp_parse,
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		.policy		= &netdev_dev_nest,
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		.free		= (void *)netdev_dev_get_ntf_free,
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	},
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	[NETDEV_CMD_DEV_DEL_NTF] =  {
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		.alloc_sz	= sizeof(struct netdev_dev_get_ntf),
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		.cb		= netdev_dev_get_rsp_parse,
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		.policy		= &netdev_dev_nest,
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		.free		= (void *)netdev_dev_get_ntf_free,
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	},
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	[NETDEV_CMD_DEV_CHANGE_NTF] =  {
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		.alloc_sz	= sizeof(struct netdev_dev_get_ntf),
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		.cb		= netdev_dev_get_rsp_parse,
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		.policy		= &netdev_dev_nest,
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		.free		= (void *)netdev_dev_get_ntf_free,
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	},
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};
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const struct ynl_family ynl_netdev_family =  {
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	.name		= "netdev",
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	.ntf_info	= netdev_ntf_info,
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	.ntf_info_size	= MNL_ARRAY_SIZE(netdev_ntf_info),
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};
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