packet: add sockopt to ignore outgoing packets
Currently, the only way to ignore outgoing packets on a packet socket is via the BPF filter. With MSG_ZEROCOPY, packets that are looped into AF_PACKET are copied in dev_queue_xmit_nit(), and this copy happens even if the filter run from packet_rcv() would reject them. So the presence of a packet socket on the interface takes away the benefits of MSG_ZEROCOPY, even if the packet socket is not interested in outgoing packets. (Even when MSG_ZEROCOPY is not used, the skb is unnecessarily cloned, but the cost for that is much lower.) Add a socket option to allow AF_PACKET sockets to ignore outgoing packets to solve this. Note that the *BSDs already have something similar: BIOCSSEESENT/BIOCSDIRECTION and BIOCSDIRFILT. The first intended user is lldpd. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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05dcc71298
Коммит
fa788d986a
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@ -2343,6 +2343,7 @@ static inline struct sk_buff *call_gro_receive_sk(gro_receive_sk_t cb,
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struct packet_type {
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__be16 type; /* This is really htons(ether_type). */
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bool ignore_outgoing;
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struct net_device *dev; /* NULL is wildcarded here */
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int (*func) (struct sk_buff *,
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struct net_device *,
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@ -57,6 +57,7 @@ struct sockaddr_ll {
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#define PACKET_QDISC_BYPASS 20
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#define PACKET_ROLLOVER_STATS 21
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#define PACKET_FANOUT_DATA 22
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#define PACKET_IGNORE_OUTGOING 23
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#define PACKET_FANOUT_HASH 0
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#define PACKET_FANOUT_LB 1
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@ -1969,6 +1969,9 @@ void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
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rcu_read_lock();
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again:
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list_for_each_entry_rcu(ptype, ptype_list, list) {
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if (ptype->ignore_outgoing)
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continue;
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/* Never send packets back to the socket
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* they originated from - MvS (miquels@drinkel.ow.org)
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*/
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@ -3805,6 +3805,20 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
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return fanout_set_data(po, optval, optlen);
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}
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case PACKET_IGNORE_OUTGOING:
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{
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int val;
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if (optlen != sizeof(val))
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return -EINVAL;
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if (copy_from_user(&val, optval, sizeof(val)))
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return -EFAULT;
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if (val < 0 || val > 1)
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return -EINVAL;
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po->prot_hook.ignore_outgoing = !!val;
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return 0;
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}
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case PACKET_TX_HAS_OFF:
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{
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unsigned int val;
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@ -3928,6 +3942,9 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
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((u32)po->fanout->flags << 24)) :
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0);
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break;
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case PACKET_IGNORE_OUTGOING:
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val = po->prot_hook.ignore_outgoing;
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break;
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case PACKET_ROLLOVER_STATS:
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if (!po->rollover)
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return -EINVAL;
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