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authorWillem de Bruijn <willemb@google.com>2022-10-28 00:10:14 +0300
committerJakub Kicinski <kuba@kernel.org>2022-10-29 08:00:49 +0300
commit58ba426388d9fe56aa638f555b01d6e63cada88c (patch)
tree3709aa38f3e61c645912c7f0d765c9c04fb4e84a
parent637639cbfebb747406b9a57befc0b347057a3a24 (diff)
downloadlinux-58ba426388d9fe56aa638f555b01d6e63cada88c.tar.xz
net/packet: add PACKET_FANOUT_FLAG_IGNORE_OUTGOING
Extend packet socket option PACKET_IGNORE_OUTGOING to fanout groups. The socket option sets ptype.ignore_outgoing, which makes dev_queue_xmit_nit skip the socket. When the socket joins a fanout group, the option is not reflected in the struct ptype of the group. dev_queue_xmit_nit only tests the fanout ptype, so the flag is ignored once a socket joins a fanout group. Inheriting the option from a socket would change established behavior. Different sockets in the group can set different flags, and can also change them at runtime. Testing in packet_rcv_fanout defeats the purpose of the original patch, which is to avoid skb_clone in dev_queue_xmit_nit (esp. for MSG_ZEROCOPY packets). Instead, introduce a new fanout group flag with the same behavior. Tested with https://github.com/wdebruij/kerneltools/blob/master/tests/test_psock_fanout_ignore_outgoing.c Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20221027211014.3581513-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--include/uapi/linux/if_packet.h1
-rw-r--r--net/packet/af_packet.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index c07caf7b40db..a8516b3594a4 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h
@@ -70,6 +70,7 @@ struct sockaddr_ll {
#define PACKET_FANOUT_EBPF 7
#define PACKET_FANOUT_FLAG_ROLLOVER 0x1000
#define PACKET_FANOUT_FLAG_UNIQUEID 0x2000
+#define PACKET_FANOUT_FLAG_IGNORE_OUTGOING 0x4000
#define PACKET_FANOUT_FLAG_DEFRAG 0x8000
struct tpacket_stats {
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 8c5b3da0c29f..44f20cf8a0c0 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1777,6 +1777,7 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
match->prot_hook.af_packet_net = read_pnet(&match->net);
match->prot_hook.id_match = match_fanout_group;
match->max_num_members = args->max_num_members;
+ match->prot_hook.ignore_outgoing = type_flags & PACKET_FANOUT_FLAG_IGNORE_OUTGOING;
list_add(&match->list, &fanout_list);
}
err = -EINVAL;