ok.
> On 2 Oct 2019, at 18:17, Claudio Jeker <cje...@diehard.n-r-g.com> wrote:
>
> umb(4) is currently the only user of DLT_RAW. The problem with this is
> that it only works for IPv4 packets and that is less than ideal.
> This diff switches umb(4) to DLT_LOOP like lo(4), tun(4), gif(4), ...
>
> To make this work the driver injects the af header in umb_decap() when
> pulling the packet of the ring and pops that header in umb_input() this
> way the common interface input handling can still be used.
> For the outbound packets umb_output() will now set ph_family header in the
> mbuf so that umb_start() can use this in bpf_mtap_af().
>
> With this tcpdump should be able to show also IPv6 packets.
> My provider does not do IPv6 (neither via umb MBIM_CID_IP_CONFIGURATION or
> via slaac) but maybe someone else has a more tech competent provider than
> me and is willing to make IPv6 go on umb(4).
> --
> :wq Claudio
>
> Index: dev/usb/if_umb.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/usb/if_umb.c,v
> retrieving revision 1.26
> diff -u -p -r1.26 if_umb.c
> --- dev/usb/if_umb.c 29 Sep 2019 15:31:16 -0000 1.26
> +++ dev/usb/if_umb.c 1 Oct 2019 11:00:10 -0000
> @@ -516,7 +516,7 @@ umb_attach(struct device *parent, struct
> if_alloc_sadl(ifp);
> ifp->if_softc = sc;
> #if NBPFILTER > 0
> - bpfattach(&ifp->if_bpf, ifp, DLT_RAW, 0);
> + bpfattach(&ifp->if_bpf, ifp, DLT_LOOP, sizeof(uint32_t));
> #endif
> /*
> * Open the device now so that we are able to query device information.
> @@ -759,19 +759,20 @@ umb_output(struct ifnet *ifp, struct mbu
> m_freem(m);
> return ENETDOWN;
> }
> + m->m_pkthdr.ph_family = dst->sa_family;
> return if_enqueue(ifp, m);
> }
>
> int
> umb_input(struct ifnet *ifp, struct mbuf *m, void *cookie)
> {
> - uint8_t ipv;
> + uint32_t af;
>
> if ((ifp->if_flags & IFF_UP) == 0) {
> m_freem(m);
> return 1;
> }
> - if (m->m_pkthdr.len < sizeof (struct ip)) {
> + if (m->m_pkthdr.len < sizeof (struct ip) + sizeof(af)) {
> ifp->if_ierrors++;
> DPRINTFN(4, "%s: dropping short packet (len %d)\n", __func__,
> m->m_pkthdr.len);
> @@ -779,16 +780,19 @@ umb_input(struct ifnet *ifp, struct mbuf
> return 1;
> }
> m->m_pkthdr.ph_rtableid = ifp->if_rdomain;
> - m_copydata(m, 0, sizeof (ipv), &ipv);
> - ipv >>= 4;
> +
> + /* pop of DLT_LOOP header, no longer needed */
> + af = *mtod(m, uint32_t *);
> + m_adj(m, sizeof (af));
> + af = ntohl(af);
>
> ifp->if_ibytes += m->m_pkthdr.len;
> - switch (ipv) {
> - case 4:
> + switch (af) {
> + case AF_INET:
> ipv4_input(ifp, m);
> return 1;
> #ifdef INET6
> - case 6:
> + case AF_INET6:
> ipv6_input(ifp, m);
> return 1;
> #endif /* INET6 */
> @@ -878,7 +882,8 @@ umb_start(struct ifnet *ifp)
>
> #if NBPFILTER > 0
> if (ifp->if_bpf)
> - bpf_mtap(ifp->if_bpf, m, BPF_DIRECTION_OUT);
> + bpf_mtap_af(ifp->if_bpf, m->m_pkthdr.ph_family, m,
> + BPF_DIRECTION_OUT);
> #endif
> }
> if (ml_empty(&sc->sc_tx_ml))
> @@ -1916,7 +1921,7 @@ umb_decap(struct umb_softc *sc, struct u
> struct ifnet *ifp = GET_IFP(sc);
> int s;
> void *buf;
> - uint32_t len;
> + uint32_t len, af = 0;
> char *dp;
> struct ncm_header16 *hdr16;
> struct ncm_header32 *hdr32;
> @@ -2033,12 +2038,25 @@ umb_decap(struct umb_softc *sc, struct u
>
> dp = buf + doff;
> DPRINTFN(3, "%s: decap %d bytes\n", DEVNAM(sc), dlen);
> - m = m_devget(dp, dlen, 0);
> + m = m_devget(dp, dlen, sizeof(uint32_t));
> if (m == NULL) {
> ifp->if_iqdrops++;
> continue;
> }
> -
> + m = m_prepend(m, sizeof(uint32_t), M_DONTWAIT);
> + if (m == NULL) {
> + ifp->if_iqdrops++;
> + continue;
> + }
> + switch (*dp & 0xf0) {
> + case 4 << 4:
> + af = htonl(AF_INET);
> + break;
> + case 6 << 4:
> + af = htonl(AF_INET6);
> + break;
> + }
> + *mtod(m, uint32_t *) = af;
> ml_enqueue(&ml, m);
> }
> done:
>
