add an optimization for dealing with raw sockets, which allows applications to filter out (among others) local tx packets on capture

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@15399 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 132 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.28/240-packet_socket_type.patch b/target/linux/generic-2.6/patches-2.6.28/240-packet_socket_type.patch
new file mode 100644
index 0000000000..741966bc6c
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.28/240-packet_socket_type.patch
@@ -0,0 +1,132 @@
+This patch allows the user to specify desired packet types (outgoing,
+broadcast, unicast, etc.) on packet sockets via setsockopt.
+This can reduce the load in situations where only a limited number
+of packet types are necessary
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+
+--- a/include/linux/if_packet.h
++++ b/include/linux/if_packet.h
+@@ -31,6 +31,8 @@ struct sockaddr_ll
+ /* These ones are invisible by user level */
+ #define PACKET_LOOPBACK		5		/* MC/BRD frame looped back */
+ #define PACKET_FASTROUTE	6		/* Fastrouted frame	*/
++#define PACKET_ANY		0xffffffff
++
+ 
+ /* Packet socket options */
+ 
+@@ -46,6 +48,7 @@ struct sockaddr_ll
+ #define PACKET_VERSION			10
+ #define PACKET_HDRLEN			11
+ #define PACKET_RESERVE			12
++#define PACKET_RECV_TYPE		13
+ 
+ struct tpacket_stats
+ {
+--- a/net/packet/af_packet.c
++++ b/net/packet/af_packet.c
+@@ -192,6 +192,7 @@ struct packet_sock {
+ 	unsigned int		tp_hdrlen;
+ 	unsigned int		tp_reserve;
+ #endif
++	int			pkt_type;
+ };
+ 
+ struct packet_skb_cb {
+@@ -282,6 +283,7 @@ static int packet_rcv_spkt(struct sk_buf
+ {
+ 	struct sock *sk;
+ 	struct sockaddr_pkt *spkt;
++	struct packet_sock *po;
+ 
+ 	/*
+ 	 *	When we registered the protocol we saved the socket in the data
+@@ -289,6 +291,7 @@ static int packet_rcv_spkt(struct sk_buf
+ 	 */
+ 
+ 	sk = pt->af_packet_priv;
++	po = pkt_sk(sk);
+ 
+ 	/*
+ 	 *	Yank back the headers [hope the device set this
+@@ -301,7 +304,7 @@ static int packet_rcv_spkt(struct sk_buf
+ 	 *	so that this procedure is noop.
+ 	 */
+ 
+-	if (skb->pkt_type == PACKET_LOOPBACK)
++	if (!(po->pkt_type & (1 << skb->pkt_type)))
+ 		goto out;
+ 
+ 	if (dev_net(dev) != sock_net(sk))
+@@ -486,12 +489,12 @@ static int packet_rcv(struct sk_buff *sk
+ 	int skb_len = skb->len;
+ 	unsigned int snaplen, res;
+ 
+-	if (skb->pkt_type == PACKET_LOOPBACK)
+-		goto drop;
+-
+ 	sk = pt->af_packet_priv;
+ 	po = pkt_sk(sk);
+ 
++	if (!(po->pkt_type & (1 << skb->pkt_type)))
++		goto drop;
++
+ 	if (dev_net(dev) != sock_net(sk))
+ 		goto drop;
+ 
+@@ -608,12 +611,12 @@ static int tpacket_rcv(struct sk_buff *s
+ 	struct timeval tv;
+ 	struct timespec ts;
+ 
+-	if (skb->pkt_type == PACKET_LOOPBACK)
+-		goto drop;
+-
+ 	sk = pt->af_packet_priv;
+ 	po = pkt_sk(sk);
+ 
++	if (!(po->pkt_type & (1 << skb->pkt_type)))
++		goto drop;
++
+ 	if (dev_net(dev) != sock_net(sk))
+ 		goto drop;
+ 
+@@ -1072,6 +1075,7 @@ static int packet_create(struct net *net
+ 	spin_lock_init(&po->bind_lock);
+ 	mutex_init(&po->pg_vec_lock);
+ 	po->prot_hook.func = packet_rcv;
++	po->pkt_type = PACKET_ANY & ~PACKET_LOOPBACK;
+ 
+ 	if (sock->type == SOCK_PACKET)
+ 		po->prot_hook.func = packet_rcv_spkt;
+@@ -1411,6 +1415,16 @@ packet_setsockopt(struct socket *sock, i
+ 			ret = packet_mc_drop(sk, &mreq);
+ 		return ret;
+ 	}
++	case PACKET_RECV_TYPE:
++	{
++		int val;
++		if (optlen != sizeof(val))
++			return -EINVAL;
++		if (copy_from_user(&val, optval, sizeof(val)))
++			return -EFAULT;
++		po->pkt_type = val & ~PACKET_LOOPBACK;
++		return 0;
++	}
+ 
+ #ifdef CONFIG_PACKET_MMAP
+ 	case PACKET_RX_RING:
+@@ -1542,6 +1556,13 @@ static int packet_getsockopt(struct sock
+ 
+ 		data = &val;
+ 		break;
++	case PACKET_RECV_TYPE:
++		if (len > sizeof(int))
++			len = sizeof(int);
++		val = po->pkt_type;
++
++		data = &val;
++		break;
+ #ifdef CONFIG_PACKET_MMAP
+ 	case PACKET_VERSION:
+ 		if (len > sizeof(int))