Date: Fri, 26 Mar 1999 19:56:53 -0500 From: Christopher Sedore <cmsedore@maxwell.syr.edu> To: "'freebsd-net@freebsd.org'" <freebsd-net@freebsd.org> Subject: bpf output bug fix Message-ID: <262C3DA9BE0CD211971700A0C9B413A1CBF1@exchange.maxwell.syr.edu>
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Since it appears that 2 people (3 if you count me :) agree that having
the kernel overwrite the source ethernet mac address on sends through
bpf is a bug, I fixed it (patch on the end).
Basically, rather than setting the dst->sa_family to AF_UNSPEC in the
bpfwrite call, I set it to AF_LINK instead. I added glue to
if_ethersubr.c to handle AF_LINK, implying that this usage would not
conflict with anything else since it wasn't handled previously.
It works as expected in my testing.
-Chris
diff -c -r sys/net/bpf.c /usr/src/sys/net/bpf.c
*** sys/net/bpf.c Mon Dec 7 21:58:36 1998
--- /usr/src/sys/net/bpf.c Fri Mar 26 19:52:37 1999
***************
*** 177,185 ****
break;
case DLT_EN10MB:
! sockp->sa_family = AF_UNSPEC;
! /* XXX Would MAXLINKHDR be better? */
! hlen = sizeof(struct ether_header);
break;
case DLT_FDDI:
--- 177,184 ----
break;
case DLT_EN10MB:
! sockp->sa_family = AF_LINK;
! hlen = 0;
break;
case DLT_FDDI:
diff -c -r sys/net/if_ethersubr.c /usr/src/sys/net/if_ethersubr.c
*** sys/net/if_ethersubr.c Tue Jan 12 12:07:00 1999
--- /usr/src/sys/net/if_ethersubr.c Fri Mar 26 18:58:58 1999
***************
*** 336,360 ****
type = eh->ether_type;
break;
default:
printf("%s%d: can't handle af%d\n", ifp->if_name,
ifp->if_unit,
dst->sa_family);
senderr(EAFNOSUPPORT);
}
! /*
! * Add local net header. If no space in first mbuf,
! * allocate another.
! */
! M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
! if (m == 0)
! senderr(ENOBUFS);
! eh = mtod(m, struct ether_header *);
! (void)memcpy(&eh->ether_type, &type,
! sizeof(eh->ether_type));
! (void)memcpy(eh->ether_dhost, edst, sizeof (edst));
! (void)memcpy(eh->ether_shost, ac->ac_enaddr,
! sizeof(eh->ether_shost));
/*
* If a simplex interface, and the packet is being sent to our
--- 336,369 ----
type = eh->ether_type;
break;
+ case AF_LINK:
+ loop_copy = -1;
+ break;
+
default:
printf("%s%d: can't handle af%d\n", ifp->if_name,
ifp->if_unit,
dst->sa_family);
senderr(EAFNOSUPPORT);
}
! if (dst->sa_family!=AF_LINK) {
!
! /*
! * Add local net header. If no space in first mbuf,
! * allocate another.
! */
! M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
! if (m == 0)
! senderr(ENOBUFS);
! eh = mtod(m, struct ether_header *);
! (void)memcpy(&eh->ether_type, &type,
! sizeof(eh->ether_type));
! (void)memcpy(eh->ether_dhost, edst, sizeof (edst));
! (void)memcpy(eh->ether_shost, ac->ac_enaddr,
! sizeof(eh->ether_shost));
! } else {
! eh = mtod(m, struct ether_header *);
! }
/*
* If a simplex interface, and the packet is being sent to our
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