svn commit: r356613 - head/sys/dev/virtio/network

[Ryan Libby]

On Fri, Jan 10, 2020 at 1:22 PM Gleb Smirnoff <glebius at freebsd.org> wrote:
>
> Author: glebius
> Date: Fri Jan 10 21:22:03 2020
> New Revision: 356613
> URL: https://svnweb.freebsd.org/changeset/base/356613
>
> Log:
>   Add pfil(9) hook to vtnet(4).
>
>   The patch could be simplier, using only the second chunk to
>   vtnet_rxq_eof(), that passes full mbufs to pfil(9). Packet
>   filter would m_free() them in case of returning PFIL_DROPPED.
>
>   However, we pretend to be a hardware driver, so we first try
>   to pass a memory buffer via PFIL_MEMPTR feature. This is mostly
>   done for debugging purposes, so that one can experiment in bhyve
>   with packet filters utilizing same features as a true driver.
>
> Modified:
>   head/sys/dev/virtio/network/if_vtnet.c
>   head/sys/dev/virtio/network/if_vtnetvar.h
>
> Modified: head/sys/dev/virtio/network/if_vtnet.c
> ==============================================================================
> --- head/sys/dev/virtio/network/if_vtnet.c      Fri Jan 10 20:53:58 2020        (r356612)
> +++ head/sys/dev/virtio/network/if_vtnet.c      Fri Jan 10 21:22:03 2020        (r356613)
> @@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$");
>
>  #include <net/debugnet.h>
>  #include <net/ethernet.h>
> +#include <net/pfil.h>
>  #include <net/if.h>
>  #include <net/if_var.h>
>  #include <net/if_arp.h>
> @@ -935,6 +936,7 @@ static int
>  vtnet_setup_interface(struct vtnet_softc *sc)
>  {
>         device_t dev;
> +       struct pfil_head_args pa;
>         struct ifnet *ifp;
>
>         dev = sc->vtnet_dev;
> @@ -1038,6 +1040,12 @@ vtnet_setup_interface(struct vtnet_softc *sc)
>
>         DEBUGNET_SET(ifp, vtnet);
>
> +       pa.pa_version = PFIL_VERSION;
> +       pa.pa_flags = PFIL_IN;
> +       pa.pa_type = PFIL_TYPE_ETHERNET;
> +       pa.pa_headname = ifp->if_xname;
> +       sc->vtnet_pfil = pfil_head_register(&pa);
> +
>         return (0);
>  }
>
> @@ -1773,9 +1781,11 @@ vtnet_rxq_eof(struct vtnet_rxq *rxq)
>         struct vtnet_softc *sc;
>         struct ifnet *ifp;
>         struct virtqueue *vq;
> -       struct mbuf *m;
> +       struct mbuf *m, *mr;
>         struct virtio_net_hdr_mrg_rxbuf *mhdr;
>         int len, deq, nbufs, adjsz, count;
> +       pfil_return_t pfil;
> +       bool pfil_done;
>
>         sc = rxq->vtnrx_sc;
>         vq = rxq->vtnrx_vq;
> @@ -1812,6 +1822,35 @@ vtnet_rxq_eof(struct vtnet_rxq *rxq)
>                         adjsz = sizeof(struct virtio_net_hdr_mrg_rxbuf);
>                 }
>
> +               /*
> +                * If we have enough data in first mbuf, run it through
> +                * pfil as a memory buffer before dequeueing the rest.
> +                */
> +               if (PFIL_HOOKED_IN(sc->vtnet_pfil) &&
> +                   len - adjsz >= ETHER_HDR_LEN + max_protohdr) {
> +                       pfil = pfil_run_hooks(sc->vtnet_pfil,
> +                           m->m_data + adjsz, ifp,
> +                           len - adjsz | PFIL_MEMPTR | PFIL_IN, NULL);

Hi Gleb,

gcc wants (len - adjsz) paranthesized.

https://ci.freebsd.org/job/FreeBSD-head-amd64-gcc/12838/
--- if_vtnet.o ---
/workspace/src/sys/dev/virtio/network/if_vtnet.c: In function 'vtnet_rxq_eof':
/workspace/src/sys/dev/virtio/network/if_vtnet.c:1833:12: error:
suggest parentheses around arithmetic in operand of '|'
[-Werror=parentheses]
        len - adjsz | PFIL_MEMPTR | PFIL_IN, NULL);
        ~~~~^~~~~~~

> +                       switch (pfil) {
> +                       case PFIL_REALLOCED:
> +                               mr = pfil_mem2mbuf(m->m_data + adjsz);
> +                               vtnet_rxq_input(rxq, mr, hdr);
> +                               /* FALLTHROUGH */
> +                       case PFIL_DROPPED:
> +                       case PFIL_CONSUMED:
> +                               vtnet_rxq_discard_buf(rxq, m);
> +                               if (nbufs > 1)
> +                                       vtnet_rxq_discard_merged_bufs(rxq,
> +                                           nbufs);
> +                               continue;
> +                       default:
> +                               KASSERT(pfil == PFIL_PASS,
> +                                   ("Filter returned %d!\n", pfil));
> +                       };
> +                       pfil_done = true;
> +               } else
> +                       pfil_done = false;
> +
>                 if (vtnet_rxq_replace_buf(rxq, m, len) != 0) {
>                         rxq->vtnrx_stats.vrxs_iqdrops++;
>                         vtnet_rxq_discard_buf(rxq, m);
> @@ -1841,6 +1880,19 @@ vtnet_rxq_eof(struct vtnet_rxq *rxq)
>                  */
>                 memcpy(hdr, mtod(m, void *), sizeof(struct virtio_net_hdr));
>                 m_adj(m, adjsz);
> +
> +               if (PFIL_HOOKED_IN(sc->vtnet_pfil) && pfil_done == false) {
> +                       pfil = pfil_run_hooks(sc->vtnet_pfil, &m, ifp, PFIL_IN,
> +                           NULL);
> +                       switch (pfil) {
> +                       case PFIL_DROPPED:
> +                       case PFIL_CONSUMED:
> +                               continue;
> +                       default:
> +                               KASSERT(pfil == PFIL_PASS,
> +                                   ("Filter returned %d!\n", pfil));
> +                       }
> +               }
>
>                 vtnet_rxq_input(rxq, m, hdr);
>
>
> Modified: head/sys/dev/virtio/network/if_vtnetvar.h
> ==============================================================================
> --- head/sys/dev/virtio/network/if_vtnetvar.h   Fri Jan 10 20:53:58 2020        (r356612)
> +++ head/sys/dev/virtio/network/if_vtnetvar.h   Fri Jan 10 21:22:03 2020        (r356613)
> @@ -136,6 +136,7 @@ struct vtnet_softc {
>         struct ifnet            *vtnet_ifp;
>         struct vtnet_rxq        *vtnet_rxqs;
>         struct vtnet_txq        *vtnet_txqs;
> +       pfil_head_t              vtnet_pfil;
>
>         uint32_t                 vtnet_flags;
>  #define VTNET_FLAG_SUSPENDED    0x0001
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