[PATCH ethtool-next v2 0/2] add netlink support for rss get

[PATCH ethtool-next v2 0/2] add netlink support for rss get

[Sudheer Mogilappagari]

These patches add netlink based handler to fetch RSS information
using "ethtool -x <eth> [context %d]" command.

Output without --json option
$ethtool -x eno2
RX flow hash indirection table for eno2 with 8 RX ring(s):
    0:      0     0     0     0     0     0     0     0
    8:      0     0     0     0     0     0     0     0
   16:      1     1     1     1     1     1     1     1
   ...skip similar lines...
  120:      7     7     7     7     7     7     7     7
RSS hash key:
be:c3:13:a6:59:9a:c3:c5:d8:60:75:2b:4c:b2:12:cc:5c:4e:34:
8a:f9:ab:16:c7:19:5d:ab:1d:b5:c1:c7:57:c7:a2:e1:2b:e3:ea:
02:60:88:8e:96:ef:2d:64:d2:de:2c:16:72:b6
RSS hash function:
    toeplitz: on
    xor: off
    crc32: off

Output with --json option
$ethtool --json -x eno2
[ {
    "ifname": "eno2",
    "RSS indirection table": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2
    ...skip similar lines...
    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 ],
    "RSS hash Key": "be:c3:13:a6:59:9a:c3:c5:d8:60:75:2b:4c:
    b2:12:cc:5c:4e:34:8a:f9:ab:16:c7:19:5d:ab:1d:b5:c1:c7:57:
    c7:a2:e1:2b:e3:ea:02:60:88:8e:96:ef:2d:64:d2:de:2c:16:72:b6",
    "RSS hash function": {
            "toeplitz": "on",
            "xor": "off",
            "crc32": "off"
        }
    } ]

Signed-off-by: Sudheer Mogilappagari <sudheer.mogilappagari@intel.com>
---
v2:
-Added json support
---
Sudheer Mogilappagari (2):
  Move code that print rss info into common file
  netlink: add netlink handler for get rss (-x)

 Makefile.am            |   2 +-
 common.c               |  43 +++++++
 common.h               |   7 ++
 ethtool.c              |  46 +------
 netlink/desc-ethtool.c |  11 ++
 netlink/extapi.h       |   2 +
 netlink/rss.c          | 272 +++++++++++++++++++++++++++++++++++++++++
 7 files changed, 342 insertions(+), 41 deletions(-)
 create mode 100644 netlink/rss.c

-- 
2.31.1

[PATCH ethtool-next v2 1/2] Move code that print rss info into common file

[Sudheer Mogilappagari]

Move functions that prints rss indirection table and hash key
into common file for use by both netlink and ioctl interface.
Changed function argument to be ring count instead of structure.

Signed-off-by: Sudheer Mogilappagari <sudheer.mogilappagari@intel.com>
---
 common.c  | 43 +++++++++++++++++++++++++++++++++++++++++++
 common.h  |  7 +++++++
 ethtool.c | 44 ++++----------------------------------------
 3 files changed, 54 insertions(+), 40 deletions(-)

diff --git a/common.c b/common.c
index 2630e73..0f2d8c0 100644
--- a/common.c
+++ b/common.c
@@ -173,3 +173,46 @@ void dump_mdix(u8 mdix, u8 mdix_ctrl)
 		fprintf(stdout, "\n");
 	}
 }
+
+void print_indir_table(struct cmd_context *ctx, u64 ring_count,
+		       u32 indir_size, u32 *indir)
+{
+	u32 i;
+
+	printf("RX flow hash indirection table for %s with %llu RX ring(s):\n",
+	       ctx->devname, ring_count);
+
+	if (!indir_size)
+		printf("Operation not supported\n");
+
+	for (i = 0; i < indir_size; i++) {
+		if (i % 8 == 0)
+			printf("%5u: ", i);
+		printf(" %5u", indir[i]);
+		if (i % 8 == 7 || i == indir_size - 1)
+			fputc('\n', stdout);
+	}
+}
+
+void print_rss_info(struct cmd_context *ctx, u64 ring_count,
+		    struct ethtool_rxfh *rss)
+{
+	u32 i, indir_bytes;
+	char *hkey;
+
+	print_indir_table(ctx, ring_count, rss->indir_size, rss->rss_config);
+
+	indir_bytes = rss->indir_size * sizeof(rss->rss_config[0]);
+	hkey = ((char *)rss->rss_config + indir_bytes);
+
+	printf("RSS hash key:\n");
+	if (!rss->key_size)
+		printf("Operation not supported\n");
+
+	for (i = 0; i < rss->key_size; i++) {
+		if (i == (rss->key_size - 1))
+			printf("%02x\n", (u8)hkey[i]);
+		else
+			printf("%02x:", (u8)hkey[i]);
+	}
+}
diff --git a/common.h b/common.h
index b74fdfa..8589714 100644
--- a/common.h
+++ b/common.h
@@ -8,6 +8,8 @@
 #define ETHTOOL_COMMON_H__
 
 #include "internal.h"
+#include <stddef.h>
+#include <errno.h>
 
 #define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))
 
@@ -41,5 +43,10 @@ extern const struct off_flag_def off_flag_def[OFF_FLAG_DEF_SIZE];
 void print_flags(const struct flag_info *info, unsigned int n_info, u32 value);
 int dump_wol(struct ethtool_wolinfo *wol);
 void dump_mdix(u8 mdix, u8 mdix_ctrl);
+void print_indir_table(struct cmd_context *ctx, u64 ring_count,
+		       u32 indir_size, u32 *indir);
+
+void print_rss_info(struct cmd_context *ctx, u64 ring_count,
+		    struct ethtool_rxfh *rss);
 
 #endif /* ETHTOOL_COMMON_H__ */
diff --git a/ethtool.c b/ethtool.c
index 60da8af..209dbd1 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -3900,27 +3900,6 @@ static int do_grxclass(struct cmd_context *ctx)
 	return err ? 1 : 0;
 }
 
-static void print_indir_table(struct cmd_context *ctx,
-			      struct ethtool_rxnfc *ring_count,
-			      u32 indir_size, u32 *indir)
-{
-	u32 i;
-
-	printf("RX flow hash indirection table for %s with %llu RX ring(s):\n",
-	       ctx->devname, ring_count->data);
-
-	if (!indir_size)
-		printf("Operation not supported\n");
-
-	for (i = 0; i < indir_size; i++) {
-		if (i % 8 == 0)
-			printf("%5u: ", i);
-		printf(" %5u", indir[i]);
-		if (i % 8 == 7 || i == indir_size - 1)
-			fputc('\n', stdout);
-	}
-}
-
 static int do_grxfhindir(struct cmd_context *ctx,
 			 struct ethtool_rxnfc *ring_count)
 {
@@ -3952,7 +3931,8 @@ static int do_grxfhindir(struct cmd_context *ctx,
 		return 1;
 	}
 
-	print_indir_table(ctx, ring_count, indir->size, indir->ring_index);
+	print_indir_table(ctx, ring_count->data, indir->size,
+			  indir->ring_index);
 
 	free(indir);
 	return 0;
@@ -3965,9 +3945,7 @@ static int do_grxfh(struct cmd_context *ctx)
 	struct ethtool_rxnfc ring_count;
 	struct ethtool_rxfh *rss;
 	u32 rss_context = 0;
-	u32 i, indir_bytes;
-	unsigned int arg_num = 0;
-	char *hkey;
+	unsigned int arg_num = 0, i;
 	int err;
 
 	while (arg_num < ctx->argc) {
@@ -4017,21 +3995,7 @@ static int do_grxfh(struct cmd_context *ctx)
 		return 1;
 	}
 
-	print_indir_table(ctx, &ring_count, rss->indir_size, rss->rss_config);
-
-	indir_bytes = rss->indir_size * sizeof(rss->rss_config[0]);
-	hkey = ((char *)rss->rss_config + indir_bytes);
-
-	printf("RSS hash key:\n");
-	if (!rss->key_size)
-		printf("Operation not supported\n");
-
-	for (i = 0; i < rss->key_size; i++) {
-		if (i == (rss->key_size - 1))
-			printf("%02x\n", (u8) hkey[i]);
-		else
-			printf("%02x:", (u8) hkey[i]);
-	}
+	print_rss_info(ctx, ring_count.data, rss);
 
 	printf("RSS hash function:\n");
 	if (!rss->hfunc) {
-- 
2.31.1

[PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Sudheer Mogilappagari]

Add support for netlink based "ethtool -x <dev>" command using
ETHTOOL_MSG_RSS_GET netlink message. It implements same functionality
provided by traditional ETHTOOL_GRSSH subcommand. This displays RSS
table, hash key and hash function along with JSON support.

Sample output with json option:
$ethtool --json -x eno2
[ {
    "ifname": "eno2",
    "RSS indirection table": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2
    ...skip similar lines...
    7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 ],
    "RSS hash Key": "be:c3:13:a6:59:9a:c3:c5:d8:60:75:2b:4c:
    b2:12:cc:5c:4e:34:8a:f9:ab:16:c7:19:5d:ab:1d:b5:c1:c7:57:
    c7:a2:e1:2b:e3:ea:02:60:88:8e:96:ef:2d:64:d2:de:2c:16:72:b6",
    "RSS hash function": {
            "toeplitz": "on",
            "xor": "off",
            "crc32": "off"
        }
    } ]

Signed-off-by: Sudheer Mogilappagari <sudheer.mogilappagari@intel.com>
---
 Makefile.am            |   2 +-
 ethtool.c              |   2 +
 netlink/desc-ethtool.c |  11 ++
 netlink/extapi.h       |   2 +
 netlink/rss.c          | 271 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 287 insertions(+), 1 deletion(-)
 create mode 100644 netlink/rss.c

diff --git a/Makefile.am b/Makefile.am
index 663f40a..c3e7401 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -39,7 +39,7 @@ ethtool_SOURCES += \
 		  netlink/eee.c netlink/tsinfo.c netlink/fec.c \
 		  netlink/stats.c \
 		  netlink/desc-ethtool.c netlink/desc-genlctrl.c \
-		  netlink/module-eeprom.c netlink/module.c \
+		  netlink/module-eeprom.c netlink/module.c netlink/rss.c \
 		  netlink/desc-rtnl.c netlink/cable_test.c netlink/tunnels.c \
 		  uapi/linux/ethtool_netlink.h \
 		  uapi/linux/netlink.h uapi/linux/genetlink.h \
diff --git a/ethtool.c b/ethtool.c
index 209dbd1..5c16b10 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -5850,7 +5850,9 @@ static const struct option args[] = {
 	},
 	{
 		.opts	= "-x|--show-rxfh-indir|--show-rxfh",
+		.json	= true,
 		.func	= do_grxfh,
+		.nlfunc	= nl_grss,
 		.help	= "Show Rx flow hash indirection table and/or RSS hash key",
 		.xhelp	= "		[ context %d ]\n"
 	},
diff --git a/netlink/desc-ethtool.c b/netlink/desc-ethtool.c
index b3ac64d..ed83dae 100644
--- a/netlink/desc-ethtool.c
+++ b/netlink/desc-ethtool.c
@@ -442,6 +442,15 @@ static const struct pretty_nla_desc __pse_desc[] = {
 	NLATTR_DESC_U32_ENUM(ETHTOOL_A_PODL_PSE_PW_D_STATUS, pse_pw_d_status),
 };
 
+static const struct pretty_nla_desc __rss_desc[] = {
+	NLATTR_DESC_INVALID(ETHTOOL_A_MODULE_UNSPEC),
+	NLATTR_DESC_NESTED(ETHTOOL_A_MODULE_HEADER, header),
+	NLATTR_DESC_U32(ETHTOOL_A_RSS_CONTEXT),
+	NLATTR_DESC_U32(ETHTOOL_A_RSS_HFUNC),
+	NLATTR_DESC_BINARY(ETHTOOL_A_RSS_INDIR),
+	NLATTR_DESC_BINARY(ETHTOOL_A_RSS_HKEY),
+};
+
 const struct pretty_nlmsg_desc ethnl_umsg_desc[] = {
 	NLMSG_DESC_INVALID(ETHTOOL_MSG_USER_NONE),
 	NLMSG_DESC(ETHTOOL_MSG_STRSET_GET, strset),
@@ -481,6 +490,7 @@ const struct pretty_nlmsg_desc ethnl_umsg_desc[] = {
 	NLMSG_DESC(ETHTOOL_MSG_MODULE_SET, module),
 	NLMSG_DESC(ETHTOOL_MSG_PSE_GET, pse),
 	NLMSG_DESC(ETHTOOL_MSG_PSE_SET, pse),
+	NLMSG_DESC(ETHTOOL_MSG_RSS_GET, rss),
 };
 
 const unsigned int ethnl_umsg_n_desc = ARRAY_SIZE(ethnl_umsg_desc);
@@ -524,6 +534,7 @@ const struct pretty_nlmsg_desc ethnl_kmsg_desc[] = {
 	NLMSG_DESC(ETHTOOL_MSG_MODULE_GET_REPLY, module),
 	NLMSG_DESC(ETHTOOL_MSG_MODULE_NTF, module),
 	NLMSG_DESC(ETHTOOL_MSG_PSE_GET_REPLY, pse),
+	NLMSG_DESC(ETHTOOL_MSG_RSS_GET_REPLY, rss),
 };
 
 const unsigned int ethnl_kmsg_n_desc = ARRAY_SIZE(ethnl_kmsg_desc);
diff --git a/netlink/extapi.h b/netlink/extapi.h
index 1bb580a..9b6dd1a 100644
--- a/netlink/extapi.h
+++ b/netlink/extapi.h
@@ -47,6 +47,7 @@ int nl_gmodule(struct cmd_context *ctx);
 int nl_smodule(struct cmd_context *ctx);
 int nl_monitor(struct cmd_context *ctx);
 int nl_getmodule(struct cmd_context *ctx);
+int nl_grss(struct cmd_context *ctx);
 
 void nl_monitor_usage(void);
 
@@ -114,6 +115,7 @@ nl_get_eeprom_page(struct cmd_context *ctx __maybe_unused,
 #define nl_getmodule		NULL
 #define nl_gmodule		NULL
 #define nl_smodule		NULL
+#define nl_grss			NULL
 
 #endif /* ETHTOOL_ENABLE_NETLINK */
 
diff --git a/netlink/rss.c b/netlink/rss.c
new file mode 100644
index 0000000..c78f60b
--- /dev/null
+++ b/netlink/rss.c
@@ -0,0 +1,271 @@
+/*
+ * rss.c - netlink implementation of RSS context commands
+ *
+ * Implementation of "ethtool -x <dev>"
+ */
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "../internal.h"
+#include "../common.h"
+#include "netlink.h"
+#include "strset.h"
+#include "parser.h"
+
+struct cb_args {
+	struct nl_context	*nlctx;
+	u32			num_rings;
+};
+
+void dump_rss_info(struct cmd_context *ctx, struct ethtool_rxfh *rss,
+		   const struct stringset *hash_funcs)
+{
+	unsigned int indir_bytes = rss->indir_size * sizeof(u32);
+	char *indir_str = NULL;
+	char *hkey_str = NULL;
+	unsigned int i;
+
+	open_json_object(NULL);
+	print_string(PRINT_JSON, "ifname", NULL, ctx->devname);
+
+	if (rss->indir_size) {
+		indir_str = calloc(1, indir_bytes * 3);
+		if (!indir_str) {
+			perror("Cannot allocate memory for RSS config");
+			goto err;
+		}
+
+		open_json_array("RSS indirection table", NULL);
+		for (i = 0; i < rss->indir_size; i++)
+			print_uint(PRINT_ANY, NULL, "%u", rss->rss_config[i]);
+		close_json_array("\n");
+	} else {
+		print_string(PRINT_JSON, "RSS indirection table", NULL,
+			     "not supported");
+	}
+
+	if (rss->key_size) {
+		const char *hkey = ((char *)rss->rss_config + indir_bytes);
+
+		hkey_str  = calloc(1, rss->key_size * 3);
+		if (!hkey_str) {
+			perror("Cannot allocate memory for RSS config");
+			goto err_hkey;
+		}
+
+		for (i = 0; i < rss->key_size; i++)
+			sprintf(hkey_str + i * 3, "%02x:", (u8)hkey[i]);
+		hkey_str[rss->key_size * 3 - 1] = '\0';
+		print_string(PRINT_JSON, "RSS hash Key", NULL, hkey_str);
+	} else {
+		print_string(PRINT_JSON, "RSS hash Key", NULL, "not supported");
+	}
+
+	if (rss->hfunc) {
+		open_json_object("RSS hash function");
+		for (unsigned int i = 0; i < get_count(hash_funcs); i++)
+			print_string(PRINT_JSON, get_string(hash_funcs, i), NULL,
+				     (rss->hfunc & (1 << i)) ? "on" : "off");
+		close_json_object();
+	} else {
+		print_string(PRINT_JSON, "RSS hash function", NULL,
+			     "not supported");
+	}
+	close_json_object();
+
+	if (hkey_str)
+		free(hkey_str);
+err_hkey:
+	if (indir_str)
+		free(indir_str);
+err:
+	return;
+}
+
+int rss_reply_cb(const struct nlmsghdr *nlhdr, void *data)
+{
+	const struct nlattr *tb[ETHTOOL_A_RSS_MAX + 1] = {};
+	unsigned int indir_bytes = 0, hkey_bytes = 0;
+	DECLARE_ATTR_TB_INFO(tb);
+	struct cb_args *args = data;
+	struct nl_context *nlctx =  args->nlctx;
+	const struct stringset *hash_funcs;
+	u32 rss_config_size, rss_hfunc;
+	const char *indir_table, *hkey;
+
+	struct ethtool_rxfh *rss;
+	bool silent;
+	int err_ret;
+	int ret;
+
+	silent = nlctx->is_dump || nlctx->is_monitor;
+	err_ret = silent ? MNL_CB_OK : MNL_CB_ERROR;
+	ret = mnl_attr_parse(nlhdr, GENL_HDRLEN, attr_cb, &tb_info);
+	if (ret < 0)
+		return err_ret;
+	nlctx->devname = get_dev_name(tb[ETHTOOL_A_RSS_HEADER]);
+	if (!dev_ok(nlctx))
+		return err_ret;
+
+	if (silent)
+		putchar('\n');
+
+	rss_hfunc = mnl_attr_get_u32(tb[ETHTOOL_A_RSS_HFUNC]);
+
+	indir_bytes = mnl_attr_get_payload_len(tb[ETHTOOL_A_RSS_INDIR]);
+	indir_table = mnl_attr_get_str(tb[ETHTOOL_A_RSS_INDIR]);
+
+	hkey_bytes = mnl_attr_get_payload_len(tb[ETHTOOL_A_RSS_HKEY]);
+	hkey = mnl_attr_get_str(tb[ETHTOOL_A_RSS_HKEY]);
+
+	rss_config_size = indir_bytes + hkey_bytes;
+
+	rss = calloc(1, sizeof(*rss) + rss_config_size);
+	if (!rss) {
+		perror("Cannot allocate memory for RX flow hash config");
+		return 1;
+	}
+
+	rss->indir_size = indir_bytes / sizeof(u32);
+	rss->key_size = hkey_bytes;
+	rss->hfunc = rss_hfunc;
+
+	memcpy(rss->rss_config, indir_table, indir_bytes);
+	memcpy(rss->rss_config + rss->indir_size, hkey, hkey_bytes);
+
+	/* Fetch RSS hash functions and their status and print */
+
+	if (!nlctx->is_monitor) {
+		ret = netlink_init_ethnl2_socket(nlctx);
+		if (ret < 0)
+			return MNL_CB_ERROR;
+	}
+	hash_funcs = global_stringset(ETH_SS_RSS_HASH_FUNCS,
+				      nlctx->ethnl2_socket);
+
+	ret = mnl_attr_parse(nlhdr, GENL_HDRLEN, attr_cb, &tb_info);
+	if (ret < 0)
+		return silent ? MNL_CB_OK : MNL_CB_ERROR;
+	nlctx->devname = get_dev_name(tb[ETHTOOL_A_RSS_HEADER]);
+	if (!dev_ok(nlctx))
+		return MNL_CB_OK;
+
+	if (is_json_context()) {
+		dump_rss_info(nlctx->ctx, rss, hash_funcs);
+	} else {
+		print_rss_info(nlctx->ctx, args->num_rings, rss);
+		printf("RSS hash function:\n");
+		if (!rss_hfunc) {
+			printf("    Operation not supported\n");
+			return 0;
+		}
+		for (unsigned int i = 0; i < get_count(hash_funcs); i++) {
+			printf("    %s: %s\n", get_string(hash_funcs, i),
+			       (rss_hfunc & (1 << i)) ? "on" : "off");
+		}
+	}
+
+	free(rss);
+	return MNL_CB_OK;
+}
+
+/* RSS_GET */
+static const struct param_parser grss_params[] = {
+	{
+		.arg		= "context",
+		.type		= ETHTOOL_A_RSS_CONTEXT,
+		.handler	= nl_parse_direct_u32,
+		.min_argc	= 1,
+	},
+	{}
+};
+
+int get_channels_cb(const struct nlmsghdr *nlhdr, void *data)
+{
+	const struct nlattr *tb[ETHTOOL_A_CHANNELS_MAX + 1] = {};
+	DECLARE_ATTR_TB_INFO(tb);
+	struct cb_args *args = data;
+	struct nl_context *nlctx =  args->nlctx;
+	bool silent;
+	int err_ret;
+	int ret;
+
+	silent = nlctx->is_dump || nlctx->is_monitor;
+	err_ret = silent ? MNL_CB_OK : MNL_CB_ERROR;
+	ret = mnl_attr_parse(nlhdr, GENL_HDRLEN, attr_cb, &tb_info);
+	if (ret < 0)
+		return err_ret;
+	nlctx->devname = get_dev_name(tb[ETHTOOL_A_CHANNELS_HEADER]);
+	if (!dev_ok(nlctx))
+		return err_ret;
+
+	args->num_rings = mnl_attr_get_u8(tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT]);
+	return MNL_CB_OK;
+}
+
+int nl_grss(struct cmd_context *ctx)
+{
+	struct nl_context *nlctx = ctx->nlctx;
+	struct nl_socket *nlsk = nlctx->ethnl_socket;
+	struct nl_msg_buff *msgbuff;
+	struct cb_args args;
+	int ret;
+
+	nlctx->cmd = "-x";
+	nlctx->argp = ctx->argp;
+	nlctx->argc = ctx->argc;
+	nlctx->devname = ctx->devname;
+	nlsk = nlctx->ethnl_socket;
+	msgbuff = &nlsk->msgbuff;
+
+	if (netlink_cmd_check(ctx, ETHTOOL_MSG_RSS_GET, true))
+		return -EOPNOTSUPP;
+
+	/* save rings information into args.num_rings */
+	if (netlink_cmd_check(ctx, ETHTOOL_MSG_CHANNELS_GET, true))
+		return -EOPNOTSUPP;
+
+	ret = nlsock_prep_get_request(nlsk, ETHTOOL_MSG_CHANNELS_GET,
+				      ETHTOOL_A_CHANNELS_HEADER, 0);
+	if (ret < 0)
+		goto err;
+
+	ret = nlsock_sendmsg(nlsk, NULL);
+	if (ret < 0)
+		goto err;
+
+	args.nlctx = nlsk->nlctx;
+	ret = nlsock_process_reply(nlsk, get_channels_cb, &args);
+	if (ret < 0)
+		goto err;
+
+	ret = msg_init(nlctx, msgbuff, ETHTOOL_MSG_RSS_GET,
+		       NLM_F_REQUEST | NLM_F_ACK);
+	if (ret < 0)
+		return 1;
+	if (ethnla_fill_header(msgbuff, ETHTOOL_A_RSS_HEADER,
+			       ctx->devname, 0))
+		return -EMSGSIZE;
+
+	ret = nl_parser(nlctx, grss_params, NULL, PARSER_GROUP_NONE, NULL);
+	if (ret < 0)
+		goto err;
+
+	new_json_obj(ctx->json);
+	ret = nlsock_sendmsg(nlsk, NULL);
+	if (ret < 0)
+		goto err;
+
+	args.nlctx = nlctx;
+	ret = nlsock_process_reply(nlsk, rss_reply_cb, &args);
+	delete_json_obj();
+
+	if (ret == 0)
+		return 0;
+
+err:
+	return nlctx->exit_code ?: 1;
+}
+
-- 
2.31.1

Re: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Jakub Kicinski]

On Wed, 21 Dec 2022 16:13:43 -0800 Sudheer Mogilappagari wrote:
> Add support for netlink based "ethtool -x <dev>" command using
> ETHTOOL_MSG_RSS_GET netlink message. It implements same functionality
> provided by traditional ETHTOOL_GRSSH subcommand. This displays RSS
> table, hash key and hash function along with JSON support.
> 
> Sample output with json option:
> $ethtool --json -x eno2
> [ {
>     "ifname": "eno2",
>     "RSS indirection table": [ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

"indirection-table"

>     1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2
>     ...skip similar lines...
>     7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 ],
>     "RSS hash Key": "be:c3:13:a6:59:9a:c3:c5:d8:60:75:2b:4c:

again, better key name, and please use an array of ints:

"hash-key": [ 190, 195, 19, ...

(Or binary encoded string (if it's compliant with JSON):

"hash-key": "\xbe\xc3\x13\xa6...

but I think array is easier to deal with.)

>     b2:12:cc:5c:4e:34:8a:f9:ab:16:c7:19:5d:ab:1d:b5:c1:c7:57:
>     c7:a2:e1:2b:e3:ea:02:60:88:8e:96:ef:2d:64:d2:de:2c:16:72:b6",
>     "RSS hash function": {
>             "toeplitz": "on",
>             "xor": "off",
>             "crc32": "off"

Please use true / false.

>         }
>     } ]


> +void dump_rss_info(struct cmd_context *ctx, struct ethtool_rxfh *rss,
> +		   const struct stringset *hash_funcs)
> +{
> +	unsigned int indir_bytes = rss->indir_size * sizeof(u32);
> +	char *indir_str = NULL;
> +	char *hkey_str = NULL;
> +	unsigned int i;
> +
> +	open_json_object(NULL);
> +	print_string(PRINT_JSON, "ifname", NULL, ctx->devname);
> +
> +	if (rss->indir_size) {
> +		indir_str = calloc(1, indir_bytes * 3);
> +		if (!indir_str) {

where is this used?

> +			perror("Cannot allocate memory for RSS config");
> +			goto err;
> +		}
> +
> +		open_json_array("RSS indirection table", NULL);
> +		for (i = 0; i < rss->indir_size; i++)
> +			print_uint(PRINT_ANY, NULL, "%u", rss->rss_config[i]);
> +		close_json_array("\n");
> +	} else {
> +		print_string(PRINT_JSON, "RSS indirection table", NULL,
> +			     "not supported");

Why not skip the field? In non-JSON output I think we use "n/a" when not
supported.

> +	}

RE: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Mogilappagari, Sudheer]

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>

> >     "RSS hash Key": "be:c3:13:a6:59:9a:c3:c5:d8:60:75:2b:4c:
> 
> again, better key name, and please use an array of ints:
> "hash-key": [ 190, 195, 19, ...
> (Or binary encoded string (if it's compliant with JSON):
> "hash-key": "\xbe\xc3\x13\xa6...
> but I think array is easier to deal with.)

Will use "RSS hash-key' as key name and array. 

Output in hex bytes like [ be,c3,13,... ] will be better
I fell but it needs below changes. Without below changes
output looks ["be", "c3", "13"...].  Will send out 
v3 (with below changes as additional patch) unless there 
is an objection. 

+++ b/json_print.c
void print_hex(enum output_type type, unsigned int hex)
 {
        if (_IS_JSON_CONTEXT(type)) {
-               SPRINT_BUF(b1);
-               snprintf(b1, sizeof(b1), "%x", hex);
                if (key)
-                       jsonw_string_field(_jw, key, b1);
+                       jsonw_xint_field(_jw, key, hex);
                else
-                       jsonw_string(_jw, b1);
+                       jsonw_xint(_jw, hex);
        } else if (_IS_FP_CONTEXT(type)) {
                fprintf(stdout, fmt, hex);
        }


> >     "RSS hash function": {
> >             "toeplitz": "on",
> >             "xor": "off",
> >             "crc32": "off"
> 
> Please use true / false.

ack

> > +	if (rss->indir_size) {
> > +		indir_str = calloc(1, indir_bytes * 3);
> > +		if (!indir_str) {
> 
> where is this used?

My bad. This was from my initial implementation before finding json_array op. 
 
> > +		print_string(PRINT_JSON, "RSS indirection table", NULL,
> > +			     "not supported");
> 
> Why not skip the field? In non-JSON output I think we use "n/a" when
> not supported.

non-json output prints "not supported". So used the same here too. 
Will skip the <key,value> pair in v3 as you suggested. 

Re: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Jakub Kicinski]

On Thu, 22 Dec 2022 22:57:19 +0000 Mogilappagari, Sudheer wrote:
> Will use "RSS hash-key' as key name and array. 

rss-hash-key ?

> Output in hex bytes like [ be,c3,13,... ] will be better
> I fell but it needs below changes. Without below changes
> output looks ["be", "c3", "13"...].  Will send out 
> v3 (with below changes as additional patch) unless there 
> is an objection. 

Hex would be great, but AFAIR JSON does not support hex :(
Imagine dealing with this in python, or bash. Do you really
want the values to be strings? They will have to get converted 
manually to integers. So I think just making them integers is
best, JSON is for machines not for looking at...

> +++ b/json_print.c
> void print_hex(enum output_type type, unsigned int hex)
>  {
>         if (_IS_JSON_CONTEXT(type)) {
> -               SPRINT_BUF(b1);
> -               snprintf(b1, sizeof(b1), "%x", hex);
>                 if (key)
> -                       jsonw_string_field(_jw, key, b1);
> +                       jsonw_xint_field(_jw, key, hex);
>                 else
> -                       jsonw_string(_jw, b1);
> +                       jsonw_xint(_jw, hex);
>         } else if (_IS_FP_CONTEXT(type)) {
>                 fprintf(stdout, fmt, hex);
>         }

Re: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Francois Romieu]

Jakub Kicinski <kuba@kernel.org> :
> On Thu, 22 Dec 2022 22:57:19 +0000 Mogilappagari, Sudheer wrote:
[...]
> > Output in hex bytes like [ be,c3,13,... ] will be better
> > I fell but it needs below changes. Without below changes
> > output looks ["be", "c3", "13"...].  Will send out 
> > v3 (with below changes as additional patch) unless there 
> > is an objection. 
> 
> Hex would be great, but AFAIR JSON does not support hex :(
> Imagine dealing with this in python, or bash. Do you really
> want the values to be strings? They will have to get converted 
> manually to integers. So I think just making them integers is
> best, JSON is for machines not for looking at...

'ip' json output does not use the suggested format.

It may be interesting to know if the experience proved it to be
a poor choice.

-- 
Ueimor

Re: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Jakub Kicinski]

On Fri, 23 Dec 2022 12:08:16 +0100 Francois Romieu wrote:
> > Hex would be great, but AFAIR JSON does not support hex :(
> > Imagine dealing with this in python, or bash. Do you really
> > want the values to be strings? They will have to get converted 
> > manually to integers. So I think just making them integers is
> > best, JSON is for machines not for looking at...  
> 
> 'ip' json output does not use the suggested format.
> 
> It may be interesting to know if the experience proved it to be
> a poor choice.

Hopefully without sounding impolite let me clarify that it is precisely
*experience* using the JSON output of ip extensively in Python and Ruby
(chef) which leads me to make the suggestion.

I made the same mistake in bpftool's JSON output, formatting binary
data as hex strings so it "looks nice" :(

Unfortunately we consider JSON output to be uAPI-like so we can't
change the format now :(

Re: [PATCH ethtool-next v2 2/2] netlink: add netlink handler for get rss (-x)

[Francois Romieu]

Jakub Kicinski <kuba@kernel.org> :
> On Fri, 23 Dec 2022 12:08:16 +0100 Francois Romieu wrote:
[...]
> > 'ip' json output does not use the suggested format.
> > 
> > It may be interesting to know if the experience proved it to be
> > a poor choice.
> 
> Hopefully without sounding impolite let me clarify that it is precisely
> *experience* using the JSON output of ip extensively in Python and Ruby
> (chef) which leads me to make the suggestion.

Thank you for the explanation.

While misguided, I've always worked under the assumption that JSON could
also be looked at (especially when tools take care of indenting it).
Knowing that there is a strict "JSON as an interchange format only" policy
and that apparent lack of consistency may be seen as the legacy of mistaken
choices is an helpful hint.

So, no place for hexadecimal, yes.

-- 
Ueimor