kernel/linux.git/net/packet/internal.h, branch v6.6.134

packet: Move reference count in packet_sock to atomic_long_t

2023-12-13T17:45:23+00:00

commit db3fadacaf0c817b222090290d06ca2a338422d0 upstream. In some potential instances the reference count on struct packet_sock could be saturated and cause overflows which gets the kernel a bit confused. To prevent this, move to a 64-bit atomic reference count on 64-bit architectures to prevent the possibility of this type to overflow. Because we can not handle saturation, using refcount_t is not possible in this place. Maybe someday in the future if it changes it could be used. Also, instead of using plain atomic64_t, use atomic_long_t instead. 32-bit machines tend to be memory-limited (i.e. anything that increases a reference uses so much memory that you can't actually get to 2**32 references). 32-bit architectures also tend to have serious problems with 64-bit atomics. Hence, atomic_long_t is the more natural solution. Reported-by: "The UK's National Cyber Security Centre (NCSC)" Co-developed-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman Signed-off-by: Daniel Borkmann Cc: Linus Torvalds Cc: stable@kernel.org Reviewed-by: Willem de Bruijn Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20231201131021.19999-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net/packet: support mergeable feature of virtio

2023-04-21T11:01:58+00:00

Packet sockets, like tap, can be used as the backend for kernel vhost. In packet sockets, virtio net header size is currently hardcoded to be the size of struct virtio_net_hdr, which is 10 bytes; however, it is not always the case: some virtio features, such as mrg_rxbuf, need virtio net header to be 12-byte long. Mergeable buffers, as a virtio feature, is worthy of supporting: packets that are larger than one-mbuf size will be dropped in vhost worker's handle_rx if mrg_rxbuf feature is not used, but large packets cannot be avoided and increasing mbuf's size is not economical. With this virtio feature enabled by virtio-user, packet sockets with hardcoded 10-byte virtio net header will parse mac head incorrectly in packet_snd by taking the last two bytes of virtio net header as part of mac header. This incorrect mac header parsing will cause packet to be dropped due to invalid ether head checking in later under-layer device packet receiving. By adding extra field vnet_hdr_sz with utilizing holes in struct packet_sock to record currently used virtio net header size and supporting extra sockopt PACKET_VNET_HDR_SZ to set specified vnet_hdr_sz, packet sockets can know the exact length of virtio net header that virtio user gives. In packet_snd, tpacket_snd and packet_recvmsg, instead of using hardcoded virtio net header size, it can get the exact vnet_hdr_sz from corresponding packet_sock, and parse mac header correctly based on this information to avoid the packets being mistakenly dropped. Signed-off-by: Jianfeng Tan Co-developed-by: Anqi Shen Signed-off-by: Anqi Shen Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

net/packet: remove po->xmit

2023-03-19T10:57:54+00:00

Use PACKET_SOCK_QDISC_BYPASS atomic bit instead of a pointer. This removes one indirect call in fast path, and READ_ONCE()/WRITE_ONCE() annotations as well. Signed-off-by: Eric Dumazet Suggested-by: Willem de Bruijn Cc: Daniel Borkmann Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

af_packet: preserve const qualifier in pkt_sk()

2023-03-18T12:23:33+00:00

We can change pkt_sk() to propagate const qualifier of its argument, thanks to container_of_const() This should avoid some potential errors caused by accidental (const -> not_const) promotion. Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net/packet: convert po->pressure to an atomic flag

2023-03-17T08:52:06+00:00

Not only this removes some READ_ONCE()/WRITE_ONCE(), this also removes one integer. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net/packet: convert po->running to an atomic flag

2023-03-17T08:52:06+00:00

Instead of consuming 32 bits for po->running, use one available bit in po->flags. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net/packet: convert po->has_vnet_hdr to an atomic flag

2023-03-17T08:52:05+00:00

po->has_vnet_hdr can be read locklessly. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net/packet: convert po->tp_loss to an atomic flag

2023-03-17T08:52:05+00:00

tp_loss can be read locklessly. Convert it to an atomic flag to avoid races. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net/packet: convert po->tp_tx_has_off to an atomic flag

2023-03-17T08:52:05+00:00

This is to use existing space in po->flags, and reclaim the storage used by the non atomic bit fields. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net/packet: convert po->auxdata to an atomic flag

2023-03-17T08:52:05+00:00

po->auxdata can be read while another thread is changing its value, potentially raising KCSAN splat. Convert it to PACKET_SOCK_AUXDATA flag. Fixes: 8dc419447415 ("[PACKET]: Add optional checksum computation for recvmsg") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller