Date: Sun, 31 Jan 1999 17:55:22 -0500 (EST) From: Bill Paul <wpaul@skynet.ctr.columbia.edu> To: current@FreeBSD.ORG Subject: SIOCADDMULTI doesn't work, proposed fix Message-ID: <199901312255.RAA01895@skynet.ctr.columbia.edu>
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After experimenting some more, I've come to the conclusion that trying to
manually add a non-IP ethernet multicast address doesn't work properly.
The ether_resolvemulti() assumes that addresses will be specified as
either AF_LINK or AF_INET; if the family is AF_LINK, it assumes that
a struct sockaddr_dl will be used. However, the user is supposed to
pass the address using a struct ifreq, and struct ifreq uses struct
sockaddr, not struct sockaddr_dl.
The original code in 2.2.x expected a struct sockaddr with a family
of AF_UNSPEC. This no longer works in 3.0, which breaks compatibility.
Among other things, the Columbia Appletalk port doesn't work because
of this.
As an aside, the equal() macro in /sys/net/if.c does a bcmp() using
sa_len as the length of the data to check, but doesn't account for
the possibility of sa_len being 0 (this makes it always return true,
which can yield false positives).
The patches included with this post change /sys/net/if.c and
/sys/net/if_ethersubr.c so that adding a mutlicast address with
SIOCADDMULTI using a struct sockaddr and AF_UNSPEC works again. I would
like Those Who Know More Than I (tm) to review these changes and offer
criticisms and comments.
These patches are against 3.0-RELEASE but should apply to -current
and -stable as well.
-Bill
--
=============================================================================
-Bill Paul (212) 854-6020 | System Manager, Master of Unix-Fu
Work: wpaul@ctr.columbia.edu | Center for Telecommunications Research
Home: wpaul@skynet.ctr.columbia.edu | Columbia University, New York City
=============================================================================
"It is not I who am crazy; it is I who am mad!" - Ren Hoek, "Space Madness"
=============================================================================
*** if.c.orig Sun Jan 31 17:13:01 1999
--- if.c Sun Jan 31 17:10:36 1999
***************
*** 186,192 ****
register struct ifaddr *ifa;
#define equal(a1, a2) \
! (bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next)
for (ifa = ifp->if_addrhead.tqh_first; ifa;
ifa = ifa->ifa_link.tqe_next) {
--- 186,193 ----
register struct ifaddr *ifa;
#define equal(a1, a2) \
! (((struct sockaddr *)(a1))->sa_len && \
! bcmp((caddr_t)(a1), (caddr_t)(a2), ((struct sockaddr *)(a1))->sa_len) == 0)
for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next)
for (ifa = ifp->if_addrhead.tqh_first; ifa;
ifa = ifa->ifa_link.tqe_next) {
***************
*** 636,642 ****
return EOPNOTSUPP;
/* Don't let users screw up protocols' entries. */
! if (ifr->ifr_addr.sa_family != AF_LINK)
return EINVAL;
if (cmd == SIOCADDMULTI) {
--- 637,644 ----
return EOPNOTSUPP;
/* Don't let users screw up protocols' entries. */
! if (ifr->ifr_addr.sa_family != AF_LINK &&
! ifr->ifr_addr.sa_family != AF_UNSPEC)
return EINVAL;
if (cmd == SIOCADDMULTI) {
*** if_ethersubr.c.orig Sun Jan 31 17:13:07 1999
--- if_ethersubr.c Sun Jan 31 17:00:54 1999
***************
*** 778,783 ****
--- 778,800 ----
u_char *e_addr;
switch(sa->sa_family) {
+ case AF_UNSPEC:
+ e_addr = (u_char *)&sa->sa_data;
+ if ((e_addr[0] & 1) != 1)
+ return EADDRNOTAVAIL;
+ MALLOC(sdl, struct sockaddr_dl *, sizeof *sdl, M_IFMADDR,
+ M_WAITOK);
+ sdl->sdl_len = sizeof *sdl;
+ sdl->sdl_family = AF_LINK;
+ sdl->sdl_index = ifp->if_index;
+ sdl->sdl_type = IFT_ETHER;
+ sdl->sdl_nlen = 0;
+ sdl->sdl_alen = ETHER_ADDR_LEN;
+ sdl->sdl_slen = 0;
+ e_addr = LLADDR(sdl);
+ bcopy((char *)&sa->sa_data, (char *)e_addr, ETHER_ADDR_LEN);
+ *llsa = (struct sockaddr *)sdl;
+ return 0;
case AF_LINK:
/*
* No mapping needed. Just check that it's a valid MC address.
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