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genet: Fix problem with forwarding some TCP/IPv6 packets

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TCP/IPv6 packets to be forwarded can be laid out with only the Ethernet
header in the first mbuf, and these packets are lost.  There was a
previous hack to pullup ICMPv6 packets with such a layout for the
same reason.  Generalize, and pullup any IPv6 packets with only the
Ethernet header in the first mbuf.  Possibly this should also include
IPv4, but that situation has not been observed to fail.

PR:		254060
Reported by:	denis at h3q.com
MFC after:	3 days
This commit is contained in:
Mike Karels 2021-03-17 19:19:24 -05:00
parent a771bf748f
commit 2bdcf62377
1 changed files with 21 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
sys/arm64/broadcom/genet/if_genet.c
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@ -76,10 +76,6 @@ __FBSDID("$FreeBSD$");
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#define ICMPV6_HACK /* workaround for chip issue */
#ifdef ICMPV6_HACK
#include <netinet/icmp6.h>
#endif
#include "syscon_if.h"
#include "miibus_if.h"
@ -955,6 +951,8 @@ gen_start_locked(struct gen_softc *sc)
if (err != 0) {
if (err == ENOBUFS)
if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
else if (m == NULL)
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
if (m != NULL)
if_sendq_prepend(ifp, m);
break;
@ -995,36 +993,34 @@ gen_encap(struct gen_softc *sc, struct mbuf **mp)
q = &sc->tx_queue[DEF_TXQUEUE];
m = *mp;
#ifdef ICMPV6_HACK
/*
* Reflected ICMPv6 packets, e.g. echo replies, tend to get laid
* out with only the Ethernet header in the first mbuf, and this
* doesn't seem to work.
* doesn't seem to work. Forwarded TCP packets over IPv6 also
* fail if laid out with only the Ethernet header in the first mbuf.
* For now, pull up any IPv6 packet with that layout. Maybe IPv4
* needs it but we haven't run into it. Pulling up the sizes of
* ether_header + ip6_header + icmp6_hdr seems to work for both
* ICMPv6 and TCP over IPv6.
*/
#define ICMP6_LEN (sizeof(struct ether_header) + sizeof(struct ip6_hdr) + \
sizeof(struct icmp6_hdr))
#define IP6_PULLUP_LEN (sizeof(struct ether_header) + \
sizeof(struct ip6_hdr) + 8)
if (m->m_len == sizeof(struct ether_header)) {
int ether_type = mtod(m, struct ether_header *)->ether_type;
if (ntohs(ether_type) == ETHERTYPE_IPV6 &&
m->m_next->m_len >= sizeof(struct ip6_hdr)) {
struct ip6_hdr *ip6;
ip6 = mtod(m->m_next, struct ip6_hdr *);
if (ip6->ip6_nxt == IPPROTO_ICMPV6) {
m = m_pullup(m,
MIN(m->m_pkthdr.len, ICMP6_LEN));
if (m == NULL) {
if (sc->ifp->if_flags & IFF_DEBUG)
device_printf(sc->dev,
"ICMPV6 pullup fail\n");
*mp = NULL;
return (ENOMEM);
}
if (ntohs(ether_type) == ETHERTYPE_IPV6) {
m = m_pullup(m, MIN(m->m_pkthdr.len, IP6_PULLUP_LEN));
if (m == NULL) {
if (sc->ifp->if_flags & IFF_DEBUG)
device_printf(sc->dev,
"IPV6 pullup fail\n");
*mp = NULL;
return (ENOMEM);
}
}
}
#undef ICMP6_LEN
#endif
#undef IP6_PULLUP_LEN
if ((if_getcapenable(sc->ifp) & (IFCAP_TXCSUM | IFCAP_TXCSUM_IPV6)) !=
0) {
csum_flags = m->m_pkthdr.csum_flags;