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if_infiniband: Support BPF write for broadcast frames #1591

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if_infiniband: Support BPF write for broadcast frames #1591

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57 changes: 52 additions & 5 deletions sys/net/if_infiniband.c
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,43 @@ infiniband_bpf_mtap(struct ifnet *ifp, struct mbuf *mb)
mb->m_pkthdr.len += sizeof(*ibh);
}

/*
* For clients using BPF to send broadcasts.
*
* This driver binds to BPF as an EN10MB (Ethernet) device type. As such, it is
* expected BPF and BPF users will send frames with Ethernet headers, which
* we'll do our best to handle. We can't resolve non-native unicast or multicast
* link-layer addresses, but we can handle broadcast frames.
*
* phlen is populated with IB header size if ibh was populated, 0 otherwise.
*/
static int
infiniband_resolve_bpf(struct ifnet *ifp, const struct sockaddr *dst,
struct mbuf *mb, const struct route *ro, struct infiniband_header *ibh,
int *phlen)
{
struct ether_header *eh = (struct ether_header *)ro->ro_prepend;
/* If the prepend data & address length don't have the signature of a frame
* forwarded by BPF, allow frame to passthrough. */
if (((ro->ro_flags & RT_HAS_HEADER) == 0) ||
(ro->ro_plen != ETHER_HDR_LEN)) {
*phlen = 0;
return (0);
}

/* Looks like this frame is from BPF. Handle broadcasts, reject otherwise */
if (!ETHER_IS_BROADCAST(eh->ether_dhost))
return (EOPNOTSUPP);

memcpy(ibh->ib_hwaddr, ifp->if_broadcastaddr, sizeof(ibh->ib_hwaddr));
ibh->ib_protocol = eh->ether_type;
mb->m_flags &= ~M_MCAST;
mb->m_flags |= M_BCAST;

*phlen = INFINIBAND_HDR_LEN;
return (0);
}

static void
update_mbuf_csumflags(struct mbuf *src, struct mbuf *dst)
{
Expand Down Expand Up @@ -306,7 +343,7 @@ infiniband_output(struct ifnet *ifp, struct mbuf *m,
struct llentry *lle = NULL;
struct infiniband_header *ih;
int error = 0;
int hlen; /* link layer header length */
int hlen = 0; /* link layer header length */
uint32_t pflags;
bool addref;

Expand All @@ -316,10 +353,20 @@ infiniband_output(struct ifnet *ifp, struct mbuf *m,
phdr = NULL;
pflags = 0;
if (ro != NULL) {
/* XXX BPF uses ro_prepend */
/* XXX BPF and ARP use ro_prepend */
if (ro->ro_prepend != NULL) {
phdr = ro->ro_prepend;
hlen = ro->ro_plen;
ih = (struct infiniband_header *)linkhdr;
/* Assess whether frame is from BPF and handle */
error = infiniband_resolve_bpf(ifp, dst, m, ro, ih, &hlen);
if (error != 0)
goto bad;

if (hlen != 0) {
phdr = linkhdr;
} else {
phdr = ro->ro_prepend;
hlen = ro->ro_plen;
}
} else if (!(m->m_flags & (M_BCAST | M_MCAST))) {
if ((ro->ro_flags & RT_LLE_CACHE) != 0) {
lle = ro->ro_lle;
Expand Down Expand Up @@ -386,7 +433,7 @@ infiniband_output(struct ifnet *ifp, struct mbuf *m,
* Add local infiniband header. If no space in first mbuf,
* allocate another.
*/
M_PREPEND(m, INFINIBAND_HDR_LEN, M_NOWAIT);
M_PREPEND(m, hlen, M_NOWAIT);
if (m == NULL) {
error = ENOBUFS;
goto bad;
Expand Down