On do, 25 apr 2019 14:31:06 +0200, Oleksij Rempel wrote:
> Hi all,
>
> please take a look at this patches. It is UAPI extension and it is good to
> know if it is sane way to track/recognize send packages.
(1) This feedback reports success or failure for packets.
That is usefull at some point.
Is there a mechanism to track the real progress. This is something I had
in /proc somewhere, and which is usefull for larger transfers ...
(2) The way I see your patch, it publishes something into an error queue.
does the err queue require emptying? what happens if you don't read the err queue?
>
> On 25.04.19 13:46, Oleksij Rempel wrote:
> >With this patches user space application is able to track the
> >status of (E)TP transfers. If this option is needed, application
> >should construct control message with PKTINFO->cookie set to some
> >value (for example pointer or sequence number). To get transmit status,
> >application should use recvmsg(..., MSG_ERRQUEUE). As response it will
> >get PKTINFO->cookie and error value if transfer was aborted. On success
> >error is set to zero.
> >
> >This example can be used to send data with attached control message and
> >cookie.
> >
> >static ssize_t jcat_sendto_flags(int fd, void *buf, size_t buf_size, int flags,
> > struct sockaddr *dest_addr,
> > socklen_t addrlen, __u64 cookie)
> >{
> > struct msghdr msgheader;
> > struct cmsghdr *control_msg;
> > struct iovec msg_iov;
> > char control_buf[256];
> > struct j1939_pktinfo *info;
> > ssize_t count;
> >
> > /* Set up iov and msgheader */
> > memset(&msgheader, 0, sizeof(struct msghdr));
> > msg_iov.iov_base = buf;
> > msg_iov.iov_len = buf_size;
> > msgheader.msg_name = dest_addr;
> > msgheader.msg_namelen = addrlen;
> > msgheader.msg_iov = &msg_iov;
> > msgheader.msg_iovlen = 1;
> > msgheader.msg_flags = 0;
> >
> > msgheader.msg_control = control_buf;
> > msgheader.msg_controllen = sizeof(control_buf);
> >
> > control_msg = CMSG_FIRSTHDR(&msgheader);
> > control_msg->cmsg_level = SOL_CAN_J1939;
> > control_msg->cmsg_type = SCM_J1939_PKTINFO;
> > control_msg->cmsg_len = CMSG_LEN(sizeof(*info));
> >
> > info = (struct j1939_pktinfo *)CMSG_DATA(control_msg);
> > memset(info, 0, sizeof(*info));
> > info->cookie = cookie;
> > msgheader.msg_controllen = control_msg->cmsg_len;
> >
> > if (((count = sendmsg(fd, &msgheader, flags))) < 0)
> > error(1, errno, "sendmsg error");
> >
> > return count;
> >}
> >
> >This example can be used to receive transfer status report.
> >
> >static int jcat_recv_err(struct jcat_priv *priv)
> >{
> > struct sock_extended_err *serr;
> > struct msghdr msg = {};
> > struct iovec iov[1];
> > struct j1939_pktinfo info;
> > struct cmsghdr *cm;
> > int ret;
> > char control[100];
> >
> > iov[0].iov_base = &info;
> > iov[0].iov_len = sizeof(info);
> > msg.msg_iov = iov ;
> > msg.msg_iovlen = 1 ;
> > msg.msg_control = control;
> > msg.msg_controllen = sizeof(control);
> >
> > ret = recvmsg(priv->sock, &msg, MSG_ERRQUEUE);
> > if (ret == -1 && errno == EAGAIN)
> > return false;
> > if (ret == -1)
> > error(1, errno, "recvmsg notification: %i", errno);
> > if (msg.msg_flags & MSG_CTRUNC)
> > error(1, errno, "recvmsg notification: truncated");
> >
> > cm = CMSG_FIRSTHDR(&msg);
> > if (!cm)
> > error(1, 0, "cmsg: no cmsg");
> >
> > if (!(cm->cmsg_level == SOL_CAN_J1939 && cm->cmsg_type == SCM_J1939_RECVERR))
> > error(1, 0, "serr: wrong type: %d.%d",
> > cm->cmsg_level, cm->cmsg_type);
> >
> > serr = (void *) CMSG_DATA(cm);
> >
> > if (serr->ee_origin != SO_EE_ORIGIN_TXSTATUS)
> > error(1, 0, "serr: wrong origin: %u", serr->ee_origin);
> >
> > if (serr->ee_errno)
> > warnx("serr: tx error: %i, %s", serr->ee_errno,
> > strerror(serr->ee_errno));
> >
> > warnx("pktinfo: cookie: 0x%llx", info.cookie);
> >
> > return serr->ee_errno;
> >}
> >
> >
> >Oleksij Rempel (2):
> > j1939: add MSG_ERRQUEUE support
> > j1939: check supported recv*() flags
> >
> > include/uapi/linux/can/j1939.h | 6 ++++
> > net/can/j1939/j1939-priv.h | 2 ++
> > net/can/j1939/socket.c | 51 ++++++++++++++++++++++++++++++++--
> > net/can/j1939/transport.c | 33 ++++++++++++++++++++--
> > 4 files changed, 86 insertions(+), 6 deletions(-)
> >
>
> Kind regards,
> Oleksij Rempel
>
> --
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