can: gw: add a per rule limitation of frame hops (391ac128) · Commits · e / devices / android_kernel_xiaomi_markw

include/uapi/linux/can/gw.h

+8 −1

Original line number	Original line	Diff line number	Diff line
	@@ -45,6 +45,7 @@ enum {
	CGW_DST_IF, /* ifindex of destination network interface */		CGW_DST_IF, /* ifindex of destination network interface */
	CGW_FILTER, /* specify struct can_filter on source CAN device */		CGW_FILTER, /* specify struct can_filter on source CAN device */
	CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */		CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */
			CGW_LIM_HOPS, /* limit the number of hops of this specific rule */
	__CGW_MAX		__CGW_MAX
	};		};

	@@ -116,13 +117,19 @@ enum {
	* Sets a CAN receive filter for the gateway job specified by the		* Sets a CAN receive filter for the gateway job specified by the
	* struct can_filter described in include/linux/can.h		* struct can_filter described in include/linux/can.h
	*		*
	* CGW_MOD_XXX (length 17 bytes):		* CGW_MOD_(AND\|OR\|XOR\|SET) (length 17 bytes):
	* Specifies a modification that's done to a received CAN frame before it is		* Specifies a modification that's done to a received CAN frame before it is
	* send out to the destination interface.		* send out to the destination interface.
	*		*
	* <struct can_frame> data used as operator		* <struct can_frame> data used as operator
	* <u8> affected CAN frame elements		* <u8> affected CAN frame elements
	*		*
			* CGW_LIM_HOPS (length 1 byte):
			* Limit the number of hops of this specific rule. Usually the received CAN
			* frame can be processed as much as 'max_hops' times (which is given at module
			* load time of the can-gw module). This value is used to reduce the number of
			* possible hops for this gateway rule to a value smaller then max_hops.
			*
	* CGW_CS_XOR (length 4 bytes):		* CGW_CS_XOR (length 4 bytes):
	* Set a simple XOR checksum starting with an initial value into		* Set a simple XOR checksum starting with an initial value into
	* data[result-idx] using data[start-idx] .. data[end-idx]		* data[result-idx] using data[start-idx] .. data[end-idx]

net/can/gw.c

+31 −4

Original line number	Original line	Diff line number	Diff line
	@@ -146,6 +146,7 @@ struct cgw_job {
	/* tbc */		/* tbc */
	};		};
	u8 gwtype;		u8 gwtype;
			u8 limit_hops;
	u16 flags;		u16 flags;
	};		};

	@@ -402,6 +403,11 @@ static void can_can_gw_rcv(struct sk_buff skb, void data)

	/* put the incremented hop counter in the cloned skb */		/* put the incremented hop counter in the cloned skb */
	cgw_hops(nskb) = cgw_hops(skb) + 1;		cgw_hops(nskb) = cgw_hops(skb) + 1;

			/* first processing of this CAN frame -> adjust to private hop limit */
			if (gwj->limit_hops && cgw_hops(nskb) == 1)
			cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;

	nskb->dev = gwj->dst.dev;		nskb->dev = gwj->dst.dev;

	/* pointer to modifiable CAN frame */		/* pointer to modifiable CAN frame */
	@@ -509,6 +515,11 @@ static int cgw_put_job(struct sk_buff skb, struct cgw_job gwj, int type,

	/* check non default settings of attributes */		/* check non default settings of attributes */

			if (gwj->limit_hops) {
			if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
			goto cancel;
			}

	if (gwj->mod.modtype.and) {		if (gwj->mod.modtype.and) {
	memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));		memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
	mb.modtype = gwj->mod.modtype.and;		mb.modtype = gwj->mod.modtype.and;
	@@ -606,11 +617,12 @@ static const struct nla_policy cgw_policy[CGW_MAX+1] = {
	[CGW_SRC_IF] = { .type = NLA_U32 },		[CGW_SRC_IF] = { .type = NLA_U32 },
	[CGW_DST_IF] = { .type = NLA_U32 },		[CGW_DST_IF] = { .type = NLA_U32 },
	[CGW_FILTER] = { .len = sizeof(struct can_filter) },		[CGW_FILTER] = { .len = sizeof(struct can_filter) },
			[CGW_LIM_HOPS] = { .type = NLA_U8 },
	};		};

	/* check for common and gwtype specific attributes */		/* check for common and gwtype specific attributes */
	static int cgw_parse_attr(struct nlmsghdr nlh, struct cf_mod mod,		static int cgw_parse_attr(struct nlmsghdr nlh, struct cf_mod mod,
	u8 gwtype, void *gwtypeattr)		u8 gwtype, void gwtypeattr, u8 limhops)
	{		{
	struct nlattr *tb[CGW_MAX+1];		struct nlattr *tb[CGW_MAX+1];
	struct cgw_frame_mod mb;		struct cgw_frame_mod mb;
	@@ -625,6 +637,13 @@ static int cgw_parse_attr(struct nlmsghdr nlh, struct cf_mod mod,
	if (err < 0)		if (err < 0)
	return err;		return err;

			if (tb[CGW_LIM_HOPS]) {
			*limhops = nla_get_u8(tb[CGW_LIM_HOPS]);

			if (limhops < 1 \|\| limhops > max_hops)
			return -EINVAL;
			}

	/* check for AND/OR/XOR/SET modifications */		/* check for AND/OR/XOR/SET modifications */

	if (tb[CGW_MOD_AND]) {		if (tb[CGW_MOD_AND]) {
	@@ -782,6 +801,7 @@ static int cgw_create_job(struct sk_buff skb, struct nlmsghdr nlh)
	{		{
	struct rtcanmsg *r;		struct rtcanmsg *r;
	struct cgw_job *gwj;		struct cgw_job *gwj;
			u8 limhops = 0;
	int err = 0;		int err = 0;

	if (!capable(CAP_NET_ADMIN))		if (!capable(CAP_NET_ADMIN))
	@@ -808,7 +828,8 @@ static int cgw_create_job(struct sk_buff skb, struct nlmsghdr nlh)
	gwj->flags = r->flags;		gwj->flags = r->flags;
	gwj->gwtype = r->gwtype;		gwj->gwtype = r->gwtype;

	err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);		err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw,
			&limhops);
	if (err < 0)		if (err < 0)
	goto out;		goto out;

	@@ -836,6 +857,8 @@ static int cgw_create_job(struct sk_buff skb, struct nlmsghdr nlh)
	if (gwj->dst.dev->type != ARPHRD_CAN \|\| gwj->dst.dev->header_ops)		if (gwj->dst.dev->type != ARPHRD_CAN \|\| gwj->dst.dev->header_ops)
	goto put_src_dst_out;		goto put_src_dst_out;

			gwj->limit_hops = limhops;

	ASSERT_RTNL();		ASSERT_RTNL();

	err = cgw_register_filter(gwj);		err = cgw_register_filter(gwj);
	@@ -874,6 +897,7 @@ static int cgw_remove_job(struct sk_buff skb, struct nlmsghdr nlh)
	struct rtcanmsg *r;		struct rtcanmsg *r;
	struct cf_mod mod;		struct cf_mod mod;
	struct can_can_gw ccgw;		struct can_can_gw ccgw;
			u8 limhops = 0;
	int err = 0;		int err = 0;

	if (!capable(CAP_NET_ADMIN))		if (!capable(CAP_NET_ADMIN))
	@@ -890,7 +914,7 @@ static int cgw_remove_job(struct sk_buff skb, struct nlmsghdr nlh)
	if (r->gwtype != CGW_TYPE_CAN_CAN)		if (r->gwtype != CGW_TYPE_CAN_CAN)
	return -EINVAL;		return -EINVAL;

	err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);		err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
	if (err < 0)		if (err < 0)
	return err;		return err;

	@@ -910,6 +934,9 @@ static int cgw_remove_job(struct sk_buff skb, struct nlmsghdr nlh)
	if (gwj->flags != r->flags)		if (gwj->flags != r->flags)
	continue;		continue;

			if (gwj->limit_hops != limhops)
			continue;

	if (memcmp(&gwj->mod, &mod, sizeof(mod)))		if (memcmp(&gwj->mod, &mod, sizeof(mod)))
	continue;		continue;