On Fri, 26 Jun 2015 14:38:42 +0800
Jason Wang <jasow...@redhat.com> wrote:
>
>
> On 06/24/2015 11:56 PM, Thomas Huth wrote:
> > Adding a proper receive_iov function to the net dump module. This
> > will make it easier to support the dump feature for the -netdev
> > option in later patches.
> > Also make the receive functions available to the other parts of the
> > source code so we can later use them for dumping from net.c, too.
> >
> > Signed-off-by: Thomas Huth <th...@redhat.com>
> > ---
> > net/clients.h | 3 +++
> > net/dump.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
> > 2 files changed, 43 insertions(+), 8 deletions(-)
> >
> > diff --git a/net/clients.h b/net/clients.h
> > index d47530e..5092f3d 100644
> > --- a/net/clients.h
> > +++ b/net/clients.h
> > @@ -29,6 +29,9 @@
> >
> > int net_init_dump(const NetClientOptions *opts, const char *name,
> > NetClientState *peer, Error **errp);
> > +ssize_t net_dump_receive(NetClientState *nc, const uint8_t *buf, size_t
> > size);
> > +ssize_t net_dump_receive_iov(NetClientState *nc, const struct iovec *iov,
> > + int cnt);
> >
> > #ifdef CONFIG_SLIRP
> > int net_init_slirp(const NetClientOptions *opts, const char *name,
> > diff --git a/net/dump.c b/net/dump.c
> > index 02c8064..383718a 100644
> > --- a/net/dump.c
> > +++ b/net/dump.c
> > @@ -57,27 +57,49 @@ struct pcap_sf_pkthdr {
> > uint32_t len;
> > };
> >
> > -static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t
> > size)
> > +ssize_t net_dump_receive_iov(NetClientState *nc, const struct iovec *iov,
> > + int cnt)
> > {
> > DumpState *s = DO_UPCAST(DumpState, nc, nc);
> > struct pcap_sf_pkthdr hdr;
> > int64_t ts;
> > - int caplen;
> > + int caplen, i;
> > + size_t size = 0;
> > + struct iovec dumpiov[cnt + 1];
> >
> > /* Early return in case of previous error. */
> > if (s->fd < 0) {
> > return size;
> > }
> >
> > + dumpiov[0].iov_base = &hdr;
> > + dumpiov[0].iov_len = sizeof(hdr);
> > + caplen = s->pcap_caplen;
> > +
> > + /* Copy iov, limit maximum size to caplen, and count total input size
> > */
> > + for (i = 0; i < cnt; i++) {
> > + dumpiov[i + 1].iov_base = iov[i].iov_base;
> > + if (size + iov[i].iov_len <= caplen) {
> > + dumpiov[i + 1].iov_len = iov[i].iov_len;
> > + } else if (size < caplen) {
> > + dumpiov[i + 1].iov_len = caplen - size;
> > + } else {
> > + dumpiov[i + 1].iov_len = 0;
> > + }
> > + size += iov[i].iov_len;
> > + }
>
> I believe we could use iov_copy() here.
Looks like that could do the job, too, thanks for the hint! However, I
also need the total size of bytes in the source iov, so I'd then need to
call iov_size() here, too - but I guess it's ok to loop through the iov
twice since dumping is not really time critical.
Thomas
