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Move ISO88025 source routing information into sockaddr_dl's sdl_data

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field.  This returns the sdl_data field to a variable-length field.  More
importantly, this prevents a easily-reproduceable data-corruption bug when
the interface name plus the hardware address exceed the sdl_data field's
original 12 byte limit.  However, token-ring interfaces may still overflow
the new sdl_data field's 46 byte limit if the interface name exceeds 6
characters (since 6 characters for interface name plus 6 for hardware
address plus 34 for source routing = the size of sdl_data).  Further
refinements could overcome this limitation but would break binary
compatibility; this commit only addresses fixing the bug for
commonly-occuring cases without breaking binary compatibility with the
intention that the functionality can be MFC'ed to -stable.

  See message ID's (both send to -arch):
	20020421013332.F87395-100000@gateway.posi.net
	20020430181359.G11009-300000@gateway.posi.net
  for a more thorough description of the bug addressed and how to
reproduce it.

Approved by:	silence on -arch and -net
Sponsored by:	NTT Multimedia Communications Labs
MFC after:	1 week
This commit is contained in:
Kelly Yancey 2002-05-07 22:14:06 +00:00
parent 0d93809e04
commit 42fdfc126a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=96184
4 changed files with 22 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/net/if_dl.h
View File

@ -66,10 +66,8 @@ struct sockaddr_dl {
u_char sdl_nlen; /* interface name length, no trailing 0 reqd. */
u_char sdl_alen; /* link level address length */
u_char sdl_slen; /* link layer selector length */
char sdl_data[12]; /* minimum work area, can be larger;
char sdl_data[46]; /* minimum work area, can be larger;
contains both if name and ll address */
u_short sdl_rcf; /* source routing control */
u_short sdl_route[16]; /* source routing information */
};
#define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))

9
sys/net/if_iso88025subr.c
View File

@ -253,8 +253,8 @@ iso88025_output(ifp, m, dst, rt0)
/* Calculate routing info length based on arp table entry */
if (rt && (sdl = (struct sockaddr_dl *)rt->rt_gateway))
if (sdl->sdl_rcf != NULL)
rif_len = TR_RCF_RIFLEN(sdl->sdl_rcf);
if (SDL_ISO88025(sdl)->trld_rcf != NULL)
rif_len = TR_RCF_RIFLEN(SDL_ISO88025(sdl)->trld_rcf);
/* Generate a generic 802.5 header for the packet */
gen_th.ac = TR_AC;
@ -264,9 +264,10 @@ iso88025_output(ifp, m, dst, rt0)
if (rif_len) {
gen_th.iso88025_shost[0] |= TR_RII;
if (rif_len > 2) {
gen_th.rcf = sdl->sdl_rcf;
gen_th.rcf = SDL_ISO88025(sdl)->trld_rcf;
(void)memcpy((caddr_t)gen_th.rd,
(caddr_t)sdl->sdl_route, rif_len - 2);
(caddr_t)SDL_ISO88025(sdl)->trld_route,
rif_len - 2);
}
}

9
sys/net/iso88025.h
View File

@ -109,6 +109,15 @@ struct iso88025_sockaddr_data {
u_char fc;
};
struct iso88025_sockaddr_dl_data {
u_short trld_rcf;
u_short *trld_route[RIF_MAX_LEN];
};
#define SDL_ISO88025(s) ((struct iso88025_sockaddr_dl_data *) \
((s)->sdl_data + min((s)->sdl_nlen + \
(s)->sdl_alen + (s)->sdl_slen, 12)))
/*
* Structure of a 48-bit iso 802.5 address.
* ( We could also add the 16 bit addresses as a union)

15
sys/netinet/if_ether.c
View File

@ -571,6 +571,7 @@ in_arpinput(m)
struct ether_header *eh;
struct arc_header *arh;
struct iso88025_header *th = (struct iso88025_header *)0;
struct iso88025_sockaddr_dl_data *trld;
register struct llinfo_arp *la = 0;
register struct rtentry *rt;
struct ifaddr *ifa;
@ -697,7 +698,6 @@ match:
}
(void)memcpy(LLADDR(sdl), ar_sha(ah),
sdl->sdl_alen = ah->ar_hln);
sdl->sdl_rcf = (u_short)0;
/*
* If we receive an arp from a token-ring station over
* a token-ring nic then try to save the source
@ -705,13 +705,14 @@ match:
*/
if (ifp->if_type == IFT_ISO88025) {
th = (struct iso88025_header *)m->m_pkthdr.header;
trld = SDL_ISO88025(sdl);
rif_len = TR_RCF_RIFLEN(th->rcf);
if ((th->iso88025_shost[0] & TR_RII) &&
(rif_len > 2)) {
sdl->sdl_rcf = th->rcf;
sdl->sdl_rcf ^= htons(TR_RCF_DIR);
memcpy(sdl->sdl_route, th->rd, rif_len - 2);
sdl->sdl_rcf &= ~htons(TR_RCF_BCST_MASK);
trld->trld_rcf = th->rcf;
trld->trld_rcf ^= htons(TR_RCF_DIR);
memcpy(trld->trld_route, th->rd, rif_len - 2);
trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK);
/*
* Set up source routing information for
* reply packet (XXX)
@ -725,9 +726,7 @@ match:
m->m_data -= 8;
m->m_len += 8;
m->m_pkthdr.len += 8;
th->rcf = sdl->sdl_rcf;
} else {
sdl->sdl_rcf = (u_short)0;
th->rcf = trld->trld_rcf;
}
if (rt->rt_expire)
rt->rt_expire = time_second + arpt_keep;