Stefano Garzarella
2021-Mar-10 10:06 UTC
[RFC PATCH v6 00/22] virtio/vsock: introduce SOCK_SEQPACKET support
Hi Arseny, thanks for this new version. It's a busy week for me, but I hope to review this series by the end of this week :-) Thanks, Stefano On Sun, Mar 07, 2021 at 08:57:19PM +0300, Arseny Krasnov wrote:> This patchset implements support of SOCK_SEQPACKET for virtio >transport. > As SOCK_SEQPACKET guarantees to save record boundaries, so to >do it, two new packet operations were added: first for start of record > and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also, >both operations carries metadata - to maintain boundaries and payload >integrity. Metadata is introduced by adding special header with two >fields - message id and message length: > > struct virtio_vsock_seq_hdr { > __le32 msg_id; > __le32 msg_len; > } __attribute__((packed)); > > This header is transmitted as payload of SEQ_BEGIN and SEQ_END >packets(buffer of second virtio descriptor in chain) in the same way as >data transmitted in RW packets. Payload was chosen as buffer for this >header to avoid touching first virtio buffer which carries header of >packet, because someone could check that size of this buffer is equal >to size of packet header. To send record, packet with start marker is >sent first(it's header carries length of record and id),then all data >is sent as usual 'RW' packets and finally SEQ_END is sent(it carries >id of message, which is equal to id of SEQ_BEGIN), also after sending >SEQ_END id is incremented. On receiver's side,size of record is known >from packet with start record marker. To check that no packets were >dropped by transport, 'msg_id's of two sequential SEQ_BEGIN and SEQ_END >are checked to be equal and length of data between two markers is >compared to then length in SEQ_BEGIN header. > Now as packets of one socket are not reordered neither on >vsock nor on vhost transport layers, such markers allows to restore >original record on receiver's side. If user's buffer is smaller that >record length, when all out of size data is dropped. > Maximum length of datagram is not limited as in stream socket, >because same credit logic is used. Difference with stream socket is >that user is not woken up until whole record is received or error >occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags. > Tests also implemented. > > Thanks to stsp2 at yandex.ru for encouragements and initial design >recommendations. > > Arseny Krasnov (22): > af_vsock: update functions for connectible socket > af_vsock: separate wait data loop > af_vsock: separate receive data loop > af_vsock: implement SEQPACKET receive loop > af_vsock: separate wait space loop > af_vsock: implement send logic for SEQPACKET > af_vsock: rest of SEQPACKET support > af_vsock: update comments for stream sockets > virtio/vsock: set packet's type in virtio_transport_send_pkt_info() > virtio/vsock: simplify credit update function API > virtio/vsock: dequeue callback for SOCK_SEQPACKET > virtio/vsock: fetch length for SEQPACKET record > virtio/vsock: add SEQPACKET receive logic > virtio/vsock: rest of SOCK_SEQPACKET support > virtio/vsock: SEQPACKET feature bit > vhost/vsock: SEQPACKET feature bit support > virtio/vsock: SEQPACKET feature bit support > virtio/vsock: setup SEQPACKET ops for transport > vhost/vsock: setup SEQPACKET ops for transport > vsock/loopback: setup SEQPACKET ops for transport > vsock_test: add SOCK_SEQPACKET tests > virtio/vsock: update trace event for SEQPACKET > > drivers/vhost/vsock.c | 22 +- > include/linux/virtio_vsock.h | 22 + > include/net/af_vsock.h | 10 + > .../events/vsock_virtio_transport_common.h | 48 +- > include/uapi/linux/virtio_vsock.h | 19 + > net/vmw_vsock/af_vsock.c | 589 +++++++++++------ > net/vmw_vsock/virtio_transport.c | 18 + > net/vmw_vsock/virtio_transport_common.c | 364 ++++++++-- > net/vmw_vsock/vsock_loopback.c | 13 + > tools/testing/vsock/util.c | 32 +- > tools/testing/vsock/util.h | 3 + > tools/testing/vsock/vsock_test.c | 126 ++++ > 12 files changed, 1013 insertions(+), 253 deletions(-) > > v5 -> v6: > General changelog: > - virtio transport specific callbacks which send SEQ_BEGIN or > SEQ_END now hidden inside virtio transport. Only enqueue, > dequeue and record length callbacks are provided by transport. > > - virtio feature bit for SEQPACKET socket support introduced: > VIRTIO_VSOCK_F_SEQPACKET. > > - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to > 'msg_id' and used as id. > > Per patch changelog: > - 'af_vsock: separate wait data loop': > 1) Commit message updated. > 2) 'prepare_to_wait()' moved inside while loop(thanks to > Jorgen Hansen). > Marked 'Reviewed-by' with 1), but as 2) I removed R-b. > > - 'af_vsock: separate receive data loop': commit message > updated. > Marked 'Reviewed-by' with that fix. > > - 'af_vsock: implement SEQPACKET receive loop': style fixes. > > - 'af_vsock: rest of SEQPACKET support': > 1) 'module_put()' added when transport callback check failed. > 2) Now only 'seqpacket_allow()' callback called to check > support of SEQPACKET by transport. > > - 'af_vsock: update comments for stream sockets': commit message > updated. > Marked 'Reviewed-by' with that fix. > > - 'virtio/vsock: set packet's type in send': > 1) Commit message updated. > 2) Parameter 'type' from 'virtio_transport_send_credit_update()' > also removed in this patch instead of in next. > > - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET > related state wrapped to special struct. > > - 'virtio/vsock: update trace event for SEQPACKET': format strings > now not broken by new lines. > > v4 -> v5: > - patches reorganized: > 1) Setting of packet's type in 'virtio_transport_send_pkt_info()' > is moved to separate patch. > 2) Simplifying of 'virtio_transport_send_credit_update()' is > moved to separate patch and before main virtio/vsock patches. > - style problem fixed > - in 'af_vsock: separate receive data loop' extra 'release_sock()' > removed > - added trace event fields for SEQPACKET > - in 'af_vsock: separate wait data loop': > 1) 'vsock_wait_data()' removed 'goto out;' > 2) Comment for invalid data amount is changed. > - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer > check is moved after 'try_module_get()' > - in 'af_vsock: update comments for stream sockets', 'connect-oriented' > replaced with 'connection-oriented' > - in 'loopback/vsock: setup SEQPACKET ops for transport', > 'loopback/vsock' replaced with 'vsock/loopback' > > v3 -> v4: > - SEQPACKET specific metadata moved from packet header to payload > and called 'virtio_vsock_seq_hdr' > - record integrity check: > 1) SEQ_END operation was added, which marks end of record. > 2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented > on every marker send. > - af_vsock.c: socket operations for STREAM and SEQPACKET call same > functions instead of having own "gates" differs only by names: > 'vsock_seqpacket/stream_getsockopt()' now replaced with > 'vsock_connectible_getsockopt()'. > - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that > record ready. There is no need to return number of copied bytes, > because case when record received successfully is checked at virtio > transport layer, when SEQ_END is processed. Also user doesn't need > number of copied bytes, because 'recv()' from SEQPACKET could return > error, length of users's buffer or length of whole record(both are > known in af_vsock.c). > - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved > to separate functions because now both called from several places. > - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport' > pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV' > if failed to use transport. > - tools/testing/vsock/vsock_test.c: rename tests > > v2 -> v3: > - patches reorganized: split for prepare and implementation patches > - local variables are declared in "Reverse Christmas tree" manner > - virtio_transport_common.c: valid leXX_to_cpu() for vsock header > fields access > - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code > between stream and seqpacket sockets. > - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored. > - af_vsock.c: 'vsock_wait_data()' refactored. > > v1 -> v2: > - patches reordered: af_vsock.c related changes now before virtio vsock > - patches reorganized: more small patches, where +/- are not mixed > - tests for SOCK_SEQPACKET added > - all commit messages updated > - af_vsock.c: 'vsock_pre_recv_check()' inlined to > 'vsock_connectible_recvmsg()' > - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport > was not found > - virtio_transport_common.c: transport callback for seqpacket dequeue > - virtio_transport_common.c: simplified > 'virtio_transport_recv_connected()' > - virtio_transport_common.c: send reset on socket and packet type > mismatch. > >Signed-off-by: Arseny Krasnov <arseny.krasnov at kaspersky.com> > >-- >2.25.1 >