netdev - [RFC PATCH 3/5] rtnl: add option for setting link bpf prog

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Message-Id: <1459560118-5582-4-git-send-email-bblanco@plumgrid.com>
Date:	Fri,  1 Apr 2016 18:21:56 -0700
From:	Brenden Blanco <bblanco@...mgrid.com>
To:	davem@...emloft.net
Cc:	Brenden Blanco <bblanco@...mgrid.com>, netdev@...r.kernel.org,
	tom@...bertland.com, alexei.starovoitov@...il.com,
	gerlitz@...lanox.com, daniel@...earbox.net,
	john.fastabend@...il.com, brouer@...hat.com
Subject: [RFC PATCH 3/5] rtnl: add option for setting link bpf prog

Sets the bpf program represented by fd as an early filter in the rx path
of the netdev. The fd must have been created as BPF_PROG_TYPE_PHYS_DEV.
Providing a negative value as fd clears the program. Getting the fd back
via rtnl is not possible, therefore reading of this value merely
provides a bool whether the program is valid on the link or not.

Signed-off-by: Brenden Blanco <bblanco@...mgrid.com>
---
 include/uapi/linux/if_link.h |  1 +
 net/core/rtnetlink.c         | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index c488066..08d66a3 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -155,6 +155,7 @@ enum {
 	IFLA_PROTO_DOWN,
 	IFLA_GSO_MAX_SEGS,
 	IFLA_GSO_MAX_SIZE,
+	IFLA_BPF_FD,
 	__IFLA_MAX
 };
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f206677..1c4a603 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -909,6 +909,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + rtnl_link_get_af_size(dev, ext_filter_mask) /* IFLA_AF_SPEC */
 	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_PORT_ID */
 	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */
+	       + nla_total_size(4) /* IFLA_BPF_FD */
 	       + nla_total_size(1); /* IFLA_PROTO_DOWN */
 
 }
@@ -1241,6 +1242,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	     nla_put_string(skb, IFLA_IFALIAS, dev->ifalias)) ||
 	    nla_put_u32(skb, IFLA_CARRIER_CHANGES,
 			atomic_read(&dev->carrier_changes)) ||
+	    nla_put_s32(skb, IFLA_BPF_FD, dev->bpf_valid) ||
 	    nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down))
 		goto nla_put_failure;
 
@@ -1374,6 +1376,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_PHYS_SWITCH_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
 	[IFLA_LINK_NETNSID]	= { .type = NLA_S32 },
 	[IFLA_PROTO_DOWN]	= { .type = NLA_U8 },
+	[IFLA_BPF_FD]		= { .type = NLA_S32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2028,6 +2031,13 @@ static int do_setlink(const struct sk_buff *skb,
 		status |= DO_SETLINK_NOTIFY;
 	}
 
+	if (tb[IFLA_BPF_FD]) {
+		err = dev_change_bpf_fd(dev, nla_get_s32(tb[IFLA_BPF_FD]));
+		if (err)
+			goto errout;
+		status |= DO_SETLINK_NOTIFY;
+	}
+
 errout:
 	if (status & DO_SETLINK_MODIFIED) {
 		if (status & DO_SETLINK_NOTIFY)
-- 
2.8.0