The ETP transfer can be as big as 112 MiB. The challenge is to keep easy
socket programming model, support 112 MiB MTU and not consume insane
amount of resources.
With this patch set, kernel do not need to copy complete 112 MiB packet in one
run. It will by copied from user space by kernel in small chunks (max
1785 Byte, which is equal to maximal TP size) and added to the session
skb queue. The size of skb queue is limited to wmem size. As soon as one
skb is transceived and confirmed by receiver, it is removed from the skb
queue and other portion of data can be copied from userspace.
For testing I wrote small too called jcat (netcat for j1939). I'll
clean it up and send pull request for can utils, with hope you'll do
more testing and bug hunting.
The test setup was configured like this:
# on sender and receiver:
ip link set can0 type can bitrate 250000
ip link set up can0
# on receiver:
jcat can0:0x90 -r > /tmp/bla
#on sender:
jcat -i /my_test_image can0:0x80 :0x90,0x12300
as you can see, the sender is not using stdin. For proper ETP testing
we need to know size of the transfer. On other hand it should be
possible to implement stdin as well, just for fun or for use in cases
like socat.
Oleksij Rempel (40):
j1939: rework j1939_send data path
j1939: transport: rework TP size check
j1939: move j1939_tp_max_packet_size to priv
j1939: transport: add j1939_xtp_rx_rts_new() function
j1939: transport: add j1939_xtp_rx_rts_current() function
j1939: transport: j1939_xtp_rx_rts: remove useless check
j1939: transport add warning for j1939_xtp_rx_rts_current()
j1939: transport: j1939_tp_send(): fix skb refcounting
j1939: transport: warn if skb can't be freed in
j1939_session_destroy()
j1939: socket: make sure all sessions are finished on close
j1939: transport: rework j1939_xtp_rx_bad_message_one
j1939: transport: move j1939_sessionq() the the
j1939_session_get_by_skb()
j1939: transport: simplify j1939_session_list_unlock()
j1939: transport: move TP_CMD related code to j1939_tp_cmd_recv()
j1939: transport: move most of j1939_session_get_by_skb to the
j1939_tp_cmd_recv
j1939: transport: use per session skcb
j1939: transport: use session->total_message_size instead of skb->len
j1939: transport: document packet related variables
j1939: add ofsset to j1939_sk_buff_cb
j1939: transport: remove useless ifindex check
j1939: transport: don't use can_skb_prv(session->skb)->ifindex with
netdev_alert
j1939: transport: add multi skb support
j1939: socket: add j1939_sk_alloc_skb()
j1939: socket: add j1939_sk_send_multi() and j1939_sk_send_one()
j1939: allow to use session by socket code
j1939: transport: don't use skb->len
j1939: socket: j1939_sk_send_multi: start using skb queue
j1939: transport: print last command in j1939_xtp_rx_rts_current in
cases of error
j1939: transport: use skcb instead of skb in transmitter or receiver
related functions
j1939: transport: rework j1939_session_fresh_new and
j1939_tp_tx_dat_new paths
j1939: transport: remove unused j1939_session_skb_find
j1939: transport: use skcb instead of skb in
j1939_tp_im_involved_anydir()
j1939: transport: remove useless check in j1939_session_cancel
j1939: transport: rework j1939_xtp_do_tx_ctl() path
j1939: transport: reduce use of j1939_session_skb_find in
j1939_tp_txnext
j1939: move j1939_socks socket list to the priv
j1939: transport: use skbc instead of skb in j1939_session_match()
path
j1939: link sock to the session
j1939: transport: remove rest of ifindex calls from netdev_* prints
j1939: bus: drop ecu_dbg
net/can/j1939/bus.c | 8 -
net/can/j1939/j1939-priv.h | 94 +++-
net/can/j1939/main.c | 26 +-
net/can/j1939/socket.c | 240 ++++++----
net/can/j1939/transport.c | 868 ++++++++++++++++++++-----------------
5 files changed, 719 insertions(+), 517 deletions(-)
--
2.19.1
