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track changes to ethernet input handling to no longer strip the Ethernet header

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Reviewed by:	many
Approved by:	re
This commit is contained in:
Sam Leffler 2002-11-14 23:57:09 +00:00
parent 673d91916d
commit 2f907a97c7
1 changed files with 55 additions and 48 deletions
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103
sys/net/bridge.c
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@ -561,6 +561,7 @@ SY(_net_link_ether, bdg_split_pkts, "Packets split in bdg_forward");
SY(_net_link_ether, bdg_thru, "Packets through bridge");
SY(_net_link_ether, bdg_copied, "Packets copied in bdg_forward");
SY(_net_link_ether, bdg_dropped, "Packets dropped in bdg_forward");
SY(_net_link_ether, bdg_copy, "Force copy in bdg_forward");
SY(_net_link_ether, bdg_predict, "Correctly predicted header location");
@ -787,12 +788,22 @@ bridge_in(struct ifnet *ifp, struct ether_header *eh)
* If possible (i.e. we can determine that the caller does not need
* a copy), the packet is consumed here, and bdg_forward returns NULL.
* Otherwise, a pointer to a copy of the packet is returned.
*
* XXX be careful with eh, it can be a pointer into *m
*/
static struct mbuf *
bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
bdg_forward(struct mbuf *m0, struct ifnet *dst)
{
#define EH_RESTORE(_m) do { \
M_PREPEND((_m), ETHER_HDR_LEN, M_NOWAIT); \
if ((_m) == NULL) { \
bdg_dropped++; \
return NULL; \
} \
if (eh != mtod((_m), struct ether_header *)) \
bcopy(&save_eh, mtod((_m), struct ether_header *), ETHER_HDR_LEN); \
else \
bdg_predict++; \
} while (0);
struct ether_header *eh;
struct ifnet *src;
struct ifnet *ifp, *last;
int shared = bdg_copy ; /* someone else is using the mbuf */
@ -803,13 +814,7 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
struct packet_filter_hook *pfh;
int rv;
#endif /* PFIL_HOOKS */
/*
* XXX eh is usually a pointer within the mbuf (some ethernet drivers
* do that), so we better copy it before doing anything with the mbuf,
* or we might corrupt the header.
*/
struct ether_header save_eh = *eh ;
struct ether_header save_eh;
DEB(quad_t ticks; ticks = rdtsc();)
@ -823,6 +828,11 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
if (args.rule == NULL)
bdg_thru++; /* first time through bdg_forward, count packet */
/*
* The packet arrives with the Ethernet header at the front.
*/
eh = mtod(m0, struct ether_header *);
src = m0->m_pkthdr.rcvif;
if (src == NULL) /* packet from ether_output */
dst = bridge_dst_lookup(eh, ifp2sc[real_dst->if_index].cluster);
@ -830,6 +840,7 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
if (dst == BDG_DROP) { /* this should not happen */
printf("xx bdg_forward for BDG_DROP\n");
m_freem(m0);
bdg_dropped++;
return NULL;
}
if (dst == BDG_LOCAL) { /* this should not happen as well */
@ -874,10 +885,21 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
m0 = m_pullup(m0, i) ;
if (m0 == NULL) {
printf("-- bdg: pullup failed.\n") ;
bdg_dropped++;
return NULL ;
}
eh = mtod(m0, struct ether_header *);
}
/*
* Processing below expects the Ethernet header is stripped.
* Furthermore, the mbuf chain might be replaced at various
* places. To deal with this we copy the header to a temporary
* location, strip the header, and restore it as needed.
*/
bcopy(eh, &save_eh, ETHER_HDR_LEN); /* local copy for restore */
m_adj(m0, ETHER_HDR_LEN); /* temporarily strip header */
#ifdef PFIL_HOOKS
/*
* NetBSD-style generic packet filter, pfil(9), hooks.
@ -897,8 +919,14 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
for (; pfh; pfh = TAILQ_NEXT(pfh, pfil_link))
if (pfh->pfil_func) {
rv = pfh->pfil_func(ip, ip->ip_hl << 2, src, 0, &m0);
if (rv != 0 || m0 == NULL)
if (m0 == NULL) {
bdg_dropped++;
return NULL;
}
if (rv != 0) {
EH_RESTORE(m0); /* restore Ethernet header */
return m0;
}
ip = mtod(m0, struct ip *);
}
/*
@ -914,8 +942,10 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
/*
* Prepare arguments and call the firewall.
*/
if (!IPFW_LOADED || bdg_ipfw == 0)
if (!IPFW_LOADED || bdg_ipfw == 0) {
EH_RESTORE(m0); /* restore Ethernet header */
goto forward; /* not using ipfw, accept the packet */
}
/*
* XXX The following code is very similar to the one in
@ -930,6 +960,8 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
i = ip_fw_chk_ptr(&args);
m0 = args.m; /* in case the firewall used the mbuf */
EH_RESTORE(m0); /* restore Ethernet header */
if ( (i & IP_FW_PORT_DENY_FLAG) || m0 == NULL) /* drop */
return m0 ;
@ -944,27 +976,14 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
if (shared) {
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) /* copy failed, give up */
return m0;
if (m == NULL) { /* copy failed, give up */
bdg_dropped++;
return NULL;
}
} else {
m = m0 ; /* pass the original to dummynet */
m0 = NULL ; /* and nothing back to the caller */
}
/*
* Prepend the header, optimize for the common case of
* eh pointing into the mbuf.
*/
if ( (void *)(eh + 1) == (void *)m->m_data) {
m->m_data -= ETHER_HDR_LEN ;
m->m_len += ETHER_HDR_LEN ;
m->m_pkthdr.len += ETHER_HDR_LEN ;
bdg_predict++;
} else {
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
if (m == NULL) /* nope... */
return m0 ;
bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
}
args.oif = real_dst;
ip_dn_io_ptr(m, (i & 0xffff),DN_TO_BDG_FWD, &args);
@ -986,9 +1005,13 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
int i = min(m0->m_pkthdr.len, max_protohdr) ;
m0 = m_pullup(m0, i) ;
if (m0 == NULL)
if (m0 == NULL) {
bdg_dropped++ ;
return NULL ;
}
/* NB: eh is not used below; no need to recalculate it */
}
/*
* now real_dst is used to determine the cluster where to forward.
* For packets coming from ether_input, this is the one of the 'src'
@ -1010,27 +1033,10 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
m = m_copypacket(m0, M_DONTWAIT);
if (m == NULL) {
printf("bdg_forward: sorry, m_copypacket failed!\n");
bdg_dropped++ ;
return m0 ; /* the original is still there... */
}
}
/*
* Add header (optimized for the common case of eh pointing
* already into the mbuf) and execute last part of ether_output:
* queue pkt and start output if interface not yet active.
*/
if ( (void *)(eh + 1) == (void *)m->m_data) {
m->m_data -= ETHER_HDR_LEN ;
m->m_len += ETHER_HDR_LEN ;
m->m_pkthdr.len += ETHER_HDR_LEN ;
bdg_predict++;
} else {
M_PREPEND(m, ETHER_HDR_LEN, M_DONTWAIT);
if (!m && verbose)
printf("M_PREPEND failed\n");
if (m == NULL)
return m0;
bcopy(&save_eh, mtod(m, struct ether_header *), ETHER_HDR_LEN);
}
if (!IF_HANDOFF(&last->if_snd, m, last)) {
#if 0
BDG_MUTE(last); /* should I also mute ? */
@ -1059,6 +1065,7 @@ bdg_forward(struct mbuf *m0, struct ether_header *const eh, struct ifnet *dst)
DEB(bdg_fw_ticks += (u_long)(rdtsc() - ticks) ; bdg_fw_count++ ;
if (bdg_fw_count != 0) bdg_fw_avg = bdg_fw_ticks/bdg_fw_count; )
return m0 ;
#undef EH_RESTORE
}
/*