Message-Id: <1577400698-4836-9-git-send-email-tom@herbertland.com>
Date:   Thu, 26 Dec 2019 14:51:37 -0800
From:   Tom Herbert <tom@...bertland.com>
To:     davem@...emloft.net, netdev@...r.kernel.org,
        simon.horman@...ronome.com, willemdebruijn.kernel@...il.com
Cc:     Tom Herbert <tom@...ntonium.net>, Tom Herbert <tom@...bertland.com>
Subject: [PATCH v8 net-next 8/9] ip6tlvs: Add netlink interface

From: Tom Herbert <tom@...ntonium.net>

Add a netlink interface to manage the TX TLV parameters. Managed
parameters include those for validating and sending TLVs being sent
such as alignment, TLV ordering, length limits, etc.

Signed-off-by: Tom Herbert <tom@...bertland.com>
---
 include/net/ipeh.h         |  16 +++
 include/net/ipv6.h         |   1 +
 include/uapi/linux/in6.h   |   6 +
 include/uapi/linux/ipeh.h  |  29 +++++
 net/ipv6/exthdrs_common.c  | 279 +++++++++++++++++++++++++++++++++++++++++++++
 net/ipv6/exthdrs_options.c |  81 ++++++++++++-
 6 files changed, 410 insertions(+), 2 deletions(-)

diff --git a/include/net/ipeh.h b/include/net/ipeh.h
index 6f46e2c..7ddbda1 100644
--- a/include/net/ipeh.h
+++ b/include/net/ipeh.h
@@ -3,6 +3,7 @@
 #define _NET_IPEH_H
 
 #include <linux/skbuff.h>
+#include <net/genetlink.h>
 
 /*
  *     Parsing tlv encoded headers.
@@ -106,6 +107,21 @@ static inline int ipeh_tlv_unset_proc(struct tlv_param_table *tlv_param_table,
 	return __ipeh_tlv_unset(tlv_param_table, type, false);
 }
 
+extern const struct nla_policy ipeh_tlv_nl_policy[];
+
+int ipeh_tlv_nl_cmd_set(struct tlv_param_table *tlv_param_table,
+			struct genl_family *tlv_nl_family,
+			struct sk_buff *skb, struct genl_info *info);
+int ipeh_tlv_nl_cmd_unset(struct tlv_param_table *tlv_param_table,
+			  struct genl_family *tlv_nl_family,
+			  struct sk_buff *skb, struct genl_info *info);
+int ipeh_tlv_nl_cmd_get(struct tlv_param_table *tlv_param_table,
+			struct genl_family *tlv_nl_family,
+			struct sk_buff *skb, struct genl_info *info);
+int ipeh_tlv_nl_dump(struct tlv_param_table *tlv_param_table,
+		     struct genl_family *tlv_nl_family,
+		     struct sk_buff *skb, struct netlink_callback *cb);
+
 /* ipeh_tlv_get_proc_by_type assumes rcu_read_lock is held */
 static inline struct tlv_proc *ipeh_tlv_get_proc_by_type(
 		struct tlv_param_table *tlv_param_table, unsigned char type)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index e290e90..68b7fb8 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -14,6 +14,7 @@
 #include <linux/jhash.h>
 #include <linux/refcount.h>
 #include <linux/jump_label_ratelimit.h>
+#include <net/genetlink.h>
 #include <net/if_inet6.h>
 #include <net/ndisc.h>
 #include <net/flow.h>
diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h
index 9f2273a..d5fe3d9 100644
--- a/include/uapi/linux/in6.h
+++ b/include/uapi/linux/in6.h
@@ -297,4 +297,10 @@ struct in6_flowlabel_req {
  * ...
  * MRT6_MAX
  */
+
+ /* NETLINK_GENERIC related info for IPv6 TLVs */
+
+#define IPV6_TLV_GENL_NAME		"ipv6-tlv"
+#define IPV6_TLV_GENL_VERSION		0x1
+
 #endif /* _UAPI_LINUX_IN6_H */
diff --git a/include/uapi/linux/ipeh.h b/include/uapi/linux/ipeh.h
index dbf0728..fb1d6e5 100644
--- a/include/uapi/linux/ipeh.h
+++ b/include/uapi/linux/ipeh.h
@@ -21,4 +21,33 @@ enum {
 	IPEH_TLV_PERM_MAX = IPEH_TLV_PERM_NO_CHECK
 };
 
+/* NETLINK_GENERIC related info for IP TLVs */
+
+enum {
+	IPEH_TLV_ATTR_UNSPEC,
+	IPEH_TLV_ATTR_TYPE,			/* u8, > 1 */
+	IPEH_TLV_ATTR_ORDER,			/* u16 */
+	IPEH_TLV_ATTR_ADMIN_PERM,		/* u8, perm value (0 to 2) */
+	IPEH_TLV_ATTR_USER_PERM,		/* u8, perm value (0 to 2) */
+	IPEH_TLV_ATTR_CLASS,			/* u8, 3 bit flags */
+	IPEH_TLV_ATTR_ALIGN_MULT,		/* u8, 1 to 16 */
+	IPEH_TLV_ATTR_ALIGN_OFF,		/* u8, 0 to 15 */
+	IPEH_TLV_ATTR_MIN_DATA_LEN,		/* u8 (option data length) */
+	IPEH_TLV_ATTR_MAX_DATA_LEN,		/* u8 (option data length) */
+	IPEH_TLV_ATTR_DATA_LEN_MULT,		/* u8, 1 to 16 */
+	IPEH_TLV_ATTR_DATA_LEN_OFF,		/* u8, 0 to 15 */
+
+	__IPEH_TLV_ATTR_MAX,
+};
+
+#define IPEH_TLV_ATTR_MAX              (__IPEH_TLV_ATTR_MAX - 1)
+
+enum {
+	IPEH_TLV_CMD_SET,
+	IPEH_TLV_CMD_UNSET,
+	IPEH_TLV_CMD_GET,
+
+	__IPEH_TLV_CMD_MAX,
+};
+
 #endif /* _UAPI_LINUX_IPEH_H */
diff --git a/net/ipv6/exthdrs_common.c b/net/ipv6/exthdrs_common.c
index e9309ea..794f3ae 100644
--- a/net/ipv6/exthdrs_common.c
+++ b/net/ipv6/exthdrs_common.c
@@ -457,6 +457,285 @@ int __ipeh_tlv_unset(struct tlv_param_table *tlv_param_table,
 }
 EXPORT_SYMBOL(__ipeh_tlv_unset);
 
+const struct nla_policy ipeh_tlv_nl_policy[IPEH_TLV_ATTR_MAX + 1] = {
+	[IPEH_TLV_ATTR_TYPE] =		{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_ORDER] =		{ .type = NLA_U16, },
+	[IPEH_TLV_ATTR_ADMIN_PERM] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_USER_PERM] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_CLASS] =		{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_ALIGN_MULT] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_ALIGN_OFF] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_MIN_DATA_LEN] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_MAX_DATA_LEN] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_DATA_LEN_OFF] =	{ .type = NLA_U8, },
+	[IPEH_TLV_ATTR_DATA_LEN_MULT] =	{ .type = NLA_U8, },
+};
+EXPORT_SYMBOL(ipeh_tlv_nl_policy);
+
+int ipeh_tlv_nl_cmd_set(struct tlv_param_table *tlv_param_table,
+			struct genl_family *tlv_nl_family,
+			struct sk_buff *skb, struct genl_info *info)
+{
+	struct tlv_params new_params;
+	struct tlv_proc *tproc;
+	unsigned char type;
+	int retv = -EINVAL;
+	unsigned int v;
+
+	if (!info->attrs[IPEH_TLV_ATTR_TYPE]) {
+		NL_SET_ERR_MSG(info->extack, "No TLV type");
+		return -EINVAL;
+	}
+
+	type = nla_get_u8(info->attrs[IPEH_TLV_ATTR_TYPE]);
+	if (type < 2) {
+		NL_SET_ERR_MSG(info->extack,
+			       "Invalid TLV type (less than 2)");
+		return -EINVAL;
+	}
+
+	rcu_read_lock();
+
+	/* Base new parameters on existing ones */
+	tproc = ipeh_tlv_get_proc_by_type(tlv_param_table, type);
+	new_params = tproc->params;
+
+	if (info->attrs[IPEH_TLV_ATTR_ORDER]) {
+		v = nla_get_u16(info->attrs[IPEH_TLV_ATTR_ORDER]);
+		new_params.t.preferred_order = v;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_ADMIN_PERM]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_ADMIN_PERM]);
+		if (v > IPEH_TLV_PERM_MAX) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Bad admin perm value");
+			goto out;
+		}
+		new_params.t.admin_perm = v;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_USER_PERM]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_USER_PERM]);
+		if (v > IPEH_TLV_PERM_MAX) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Bad user perm value");
+			goto out;
+		}
+		new_params.t.user_perm = v;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_CLASS]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_CLASS]);
+		if (!v || (v & ~IPEH_TLV_CLASS_FLAG_MASK)) {
+			NL_SET_ERR_MSG(info->extack, "Bad TLV class");
+			goto out;
+		}
+		new_params.t.class = v;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_ALIGN_MULT]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_ALIGN_MULT]);
+		if (v > 16 || v < 1) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Alignment must be < 16 and > 0");
+			goto out;
+		}
+		new_params.t.align_mult = v - 1;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_ALIGN_OFF]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_ALIGN_OFF]);
+		if (v > 15) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Alignment offset must be < 16");
+			goto out;
+		}
+		new_params.t.align_off = v;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_MAX_DATA_LEN])
+		new_params.t.max_data_len =
+		    nla_get_u8(info->attrs[IPEH_TLV_ATTR_MAX_DATA_LEN]);
+
+	if (info->attrs[IPEH_TLV_ATTR_MIN_DATA_LEN])
+		new_params.t.min_data_len =
+		    nla_get_u8(info->attrs[IPEH_TLV_ATTR_MIN_DATA_LEN]);
+
+	if (new_params.t.min_data_len > new_params.t.max_data_len) {
+		NL_SET_ERR_MSG(info->extack,
+			       "Min data length must be less than or equal to max data length");
+		goto out;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_DATA_LEN_MULT]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_DATA_LEN_MULT]);
+		if (v > 16 || v < 1) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Length multiple must be < 16 and > 0");
+			goto out;
+		}
+		new_params.t.data_len_mult = v - 1;
+	}
+
+	if (info->attrs[IPEH_TLV_ATTR_DATA_LEN_OFF]) {
+		v = nla_get_u8(info->attrs[IPEH_TLV_ATTR_DATA_LEN_OFF]);
+		if (v > 15) {
+			NL_SET_ERR_MSG(info->extack,
+				       "Data length offset must be < 16");
+			goto out;
+		}
+		new_params.t.data_len_off = v;
+	}
+
+	retv = ipeh_tlv_set_params(tlv_param_table, type, &new_params);
+
+out:
+	rcu_read_unlock();
+	return retv;
+}
+EXPORT_SYMBOL(ipeh_tlv_nl_cmd_set);
+
+int ipeh_tlv_nl_cmd_unset(struct tlv_param_table *tlv_param_table,
+			  struct genl_family *tlv_nl_family,
+			  struct sk_buff *skb, struct genl_info *info)
+{
+	unsigned char type;
+
+	if (!info->attrs[IPEH_TLV_ATTR_TYPE]) {
+		NL_SET_ERR_MSG(info->extack, "No TLV type");
+		return -EINVAL;
+	}
+
+	type = nla_get_u8(info->attrs[IPEH_TLV_ATTR_TYPE]);
+	if (type < 2) {
+		NL_SET_ERR_MSG(info->extack,
+			       "Invalid TLV type (less than 2)");
+		return -EINVAL;
+	}
+
+	return ipeh_tlv_unset_params(tlv_param_table, type);
+}
+EXPORT_SYMBOL(ipeh_tlv_nl_cmd_unset);
+
+static int tlv_fill_info(struct tlv_proc *tproc, unsigned char type,
+			 struct sk_buff *msg, bool admin)
+{
+	struct tlv_params *tp = &tproc->params;
+	int ret = 0;
+
+	if (nla_put_u8(msg, IPEH_TLV_ATTR_TYPE, type) ||
+	    nla_put_u16(msg, IPEH_TLV_ATTR_ORDER, tp->t.preferred_order) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_USER_PERM, tp->t.user_perm) ||
+	    (admin && nla_put_u8(msg, IPEH_TLV_ATTR_ADMIN_PERM,
+				 tp->t.admin_perm)) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_CLASS, tp->t.class) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_ALIGN_MULT, tp->t.align_mult + 1) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_ALIGN_OFF, tp->t.align_off) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_MIN_DATA_LEN, tp->t.min_data_len) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_MAX_DATA_LEN, tp->t.max_data_len) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_DATA_LEN_MULT,
+		       tp->t.data_len_mult + 1) ||
+	    nla_put_u8(msg, IPEH_TLV_ATTR_DATA_LEN_OFF, tp->t.data_len_off))
+		ret = -1;
+
+	return ret;
+}
+
+static int tlv_dump_info(struct tlv_proc *tproc, unsigned char type,
+			 struct genl_family *tlv_nl_family, u32 portid,
+			 u32 seq, u32 flags, struct sk_buff *skb, u8 cmd,
+			 bool admin)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(skb, portid, seq, tlv_nl_family, flags, cmd);
+	if (!hdr)
+		return -ENOMEM;
+
+	if (tlv_fill_info(tproc, type, skb, admin) < 0) {
+		genlmsg_cancel(skb, hdr);
+		return -EMSGSIZE;
+	}
+
+	genlmsg_end(skb, hdr);
+
+	return 0;
+}
+
+int ipeh_tlv_nl_cmd_get(struct tlv_param_table *tlv_param_table,
+			struct genl_family *tlv_nl_family,
+			struct sk_buff *skb, struct genl_info *info)
+{
+	struct tlv_proc *tproc;
+	struct sk_buff *msg;
+	unsigned char type;
+	int ret;
+
+	if (!info->attrs[IPEH_TLV_ATTR_TYPE]) {
+		NL_SET_ERR_MSG(info->extack, "No TLV type");
+		return -EINVAL;
+	}
+
+	type = nla_get_u8(info->attrs[IPEH_TLV_ATTR_TYPE]);
+	if (type < 2) {
+		NL_SET_ERR_MSG(info->extack,
+			       "Invalid TLV type (less than 2)");
+		return -EINVAL;
+	}
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	rcu_read_lock();
+
+	tproc = ipeh_tlv_get_proc_by_type(tlv_param_table, type);
+	ret = tlv_dump_info(tproc, type, tlv_nl_family, info->snd_portid,
+			    info->snd_seq, 0, msg, info->genlhdr->cmd,
+			    netlink_capable(skb, CAP_NET_ADMIN));
+
+	rcu_read_unlock();
+
+	if (ret < 0) {
+		nlmsg_free(msg);
+		return ret;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+EXPORT_SYMBOL(ipeh_tlv_nl_cmd_get);
+
+int ipeh_tlv_nl_dump(struct tlv_param_table *tlv_param_table,
+		     struct genl_family *tlv_nl_family,
+		     struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct tlv_proc *tproc;
+	int idx = 0, ret, i;
+
+	rcu_read_lock();
+
+	for (i = 2; i < 256; i++) {
+		if (idx++ < cb->args[0])
+			continue;
+
+		tproc = ipeh_tlv_get_proc_by_type(tlv_param_table, i);
+		ret = tlv_dump_info(tproc, i, tlv_nl_family,
+				    NETLINK_CB(cb->skb).portid,
+				    cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				    skb, IPEH_TLV_CMD_GET,
+				    netlink_capable(cb->skb, CAP_NET_ADMIN));
+		if (ret)
+			break;
+	}
+
+	rcu_read_unlock();
+
+	cb->args[0] = idx;
+	return skb->len;
+}
+EXPORT_SYMBOL(ipeh_tlv_nl_dump);
+
 int ipeh_exthdrs_init(struct tlv_param_table *tlv_param_table,
 		      const struct tlv_proc_init *tlv_init_params,
 		      int num_init_params)
diff --git a/net/ipv6/exthdrs_options.c b/net/ipv6/exthdrs_options.c
index 3b50b58..c1889f6 100644
--- a/net/ipv6/exthdrs_options.c
+++ b/net/ipv6/exthdrs_options.c
@@ -6,6 +6,7 @@
 #include <linux/socket.h>
 #include <linux/types.h>
 #include <net/calipso.h>
+#include <net/genetlink.h>
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #if IS_ENABLED(CONFIG_IPV6_MIP6)
@@ -253,13 +254,89 @@ static const struct tlv_proc_init tlv_ipv6_init_params[] __initconst = {
 struct tlv_param_table __rcu ipv6_tlv_param_table;
 EXPORT_SYMBOL(ipv6_tlv_param_table);
 
+static int ipv6_tlv_nl_cmd_set(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_cmd_unset(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_cmd_get(struct sk_buff *skb, struct genl_info *info);
+static int ipv6_tlv_nl_dump(struct sk_buff *skb, struct netlink_callback *cb);
+
+static const struct genl_ops ipv6_tlv_nl_ops[] = {
+{
+	.cmd = IPEH_TLV_CMD_SET,
+	.doit = ipv6_tlv_nl_cmd_set,
+	.flags = GENL_ADMIN_PERM,
+},
+{
+	.cmd = IPEH_TLV_CMD_UNSET,
+	.doit = ipv6_tlv_nl_cmd_unset,
+	.flags = GENL_ADMIN_PERM,
+},
+{
+	.cmd = IPEH_TLV_CMD_GET,
+	.doit = ipv6_tlv_nl_cmd_get,
+	.dumpit = ipv6_tlv_nl_dump,
+},
+};
+
+struct genl_family ipv6_tlv_nl_family __ro_after_init = {
+	.hdrsize	= 0,
+	.name		= IPV6_TLV_GENL_NAME,
+	.version	= IPV6_TLV_GENL_VERSION,
+	.maxattr	= IPEH_TLV_ATTR_MAX,
+	.policy		= ipeh_tlv_nl_policy,
+	.netnsok	= true,
+	.parallel_ops	= true,
+	.ops		= ipv6_tlv_nl_ops,
+	.n_ops		= ARRAY_SIZE(ipv6_tlv_nl_ops),
+	.module		= THIS_MODULE,
+};
+
+static int ipv6_tlv_nl_cmd_set(struct sk_buff *skb, struct genl_info *info)
+{
+	return ipeh_tlv_nl_cmd_set(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+				   skb, info);
+}
+
+static int ipv6_tlv_nl_cmd_unset(struct sk_buff *skb, struct genl_info *info)
+{
+	return ipeh_tlv_nl_cmd_unset(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+				     skb, info);
+}
+
+static int ipv6_tlv_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
+{
+	return ipeh_tlv_nl_cmd_get(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+				   skb, info);
+}
+
+static int ipv6_tlv_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	return ipeh_tlv_nl_dump(&ipv6_tlv_param_table, &ipv6_tlv_nl_family,
+				skb, cb);
+}
+
 int __init ipv6_exthdrs_options_init(void)
 {
-	return ipeh_exthdrs_init(&ipv6_tlv_param_table, tlv_ipv6_init_params,
-				 ARRAY_SIZE(tlv_ipv6_init_params));
+	int err;
+
+	err = genl_register_family(&ipv6_tlv_nl_family);
+	if (err)
+		goto genl_fail;
+
+	ipeh_exthdrs_init(&ipv6_tlv_param_table, tlv_ipv6_init_params,
+			  ARRAY_SIZE(tlv_ipv6_init_params));
+	if (err)
+		goto ipv6_fail;
+
+	return 0;
+
+ipv6_fail:
+	genl_unregister_family(&ipv6_tlv_nl_family);
+genl_fail:
+	return err;
 }
 
 void ipv6_exthdrs_options_exit(void)
 {
 	ipeh_exthdrs_fini(&ipv6_tlv_param_table);
+	genl_unregister_family(&ipv6_tlv_nl_family);
 }
-- 
2.7.4

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