2004-12-29 Greg Troxel <gdt@poblano.ir.bbn.com>

* sockopt.c (getsockopt_ipv4_ifindex): Document calling
	convention.  Beef up comments.  Handle the case where the cmsghdr
	has a zero controllen, or more specifically when the wanted option
	is not present.  This is needed for Solaris 8, and in general for
	any platform for which configure finds a method and it can fail.
	Mark some changes with XXX to be cleaned up post 0.98.
This commit is contained in:
gdt 2004-12-29 20:06:23 +00:00
parent 4660687a38
commit d44debedf5
2 changed files with 50 additions and 35 deletions

View File

@ -1,8 +1,12 @@
2004-12-29 Greg Troxel <gdt@poblano.ir.bbn.com>
* sockopt.c (getsockopt_ipv4_ifindex): Return 0 when passed a NULL
cmsghdr pointer.
* sockopt.c (getsockopt_ipv4_ifindex): Document calling
convention. Beef up comments. Handle the case where the cmsghdr
has a zero controllen, or more specifically when the wanted option
is not present. This is needed for Solaris 8, and in general for
any platform for which configure finds a method and it can fail.
Mark some changes with XXX to be cleaned up post 0.98.
2004-12-28 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
* sockopt.c: (setsockopt_ipv4_ifindex) Improve error message.

View File

@ -280,63 +280,74 @@ setsockopt_ifindex (int af, int sock, int val)
return ret;
}
/*
* Requires: msgh is not NULL and points to a valid struct msghdr, which
* may or may not have control data about the incoming interface.
*
* Returns the interface index (small integer >= 1) if it can be
* determined, or else 0.
*/
static int
getsockopt_ipv4_ifindex (struct msghdr *msgh)
{
/*
* XXX: This routine's semantics are ill-defined, in particular how
* the results "can't determine interface due to runtime behavior"
* and "OS has no support for how to determine behavior" are
* encoded. For now, return 0 for either case; caller must handle
* as "don't know".
*/
/* XXX: initialize to zero? (Always overwritten, so just cosmetic.) */
int ifindex = -1;
/*
* If autoconf found a method to get ifindex, but it didn't work for
* this packet, or on this OS, this routine can be entered with a
* NULL cmsghdr pointer. Check msgh before using in each case
* below, rather than here, to avoid having to ifdef twice, once for
* declarations and once for code.
*/
#if defined(IP_PKTINFO)
/* Linux pktinfo based ifindex retrieval */
struct in_pktinfo *pktinfo;
if (msgh == NULL)
return 0;
pktinfo =
(struct in_pktinfo *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_PKTINFO);
/* XXX Can pktinfo be NULL? Clean up post 0.98. */
ifindex = pktinfo->ipi_ifindex;
#elif defined(IP_RECVIF)
/* BSD/other IP_RECVIF based ifindex retrieval */
/* retrieval based on IP_RECVIF */
#ifndef SUNOS_5
/* RECVIF, but not SUNOS, so BSD */
/* BSD systems use a sockaddr_dl as the control message payload. */
struct sockaddr_dl *sdl;
#else
/* SUNOS_5 uses an integer with the index. */
int *ifindex_p;
#endif /* SUNOS_5 */
/* SUNOS_5 doesn't need a structure to extract ifindex */
if (msgh == NULL)
return 0;
#ifndef SUNOS_5
/* BSD */
sdl =
(struct sockaddr_dl *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_RECVIF);
ifindex = sdl->sdl_index;
#else /* !SUNOS_5 */
ifindex = *(uint_t *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_RECVIF);
if (sdl != NULL)
ifindex = sdl->sdl_index;
else
ifindex = 0;
#else
/*
* Solaris. On Solaris 8, IP_RECVIF is defined, but the call to
* enable it fails with errno=99, and the struct msghdr has
* controllen 0.
*/
ifindex_p = (uint_t *)getsockopt_cmsg_data (msgh, IPPROTO_IP, IP_RECVIF);
if (ifindex_p != NULL)
ifindex = *ifindex_p;
else
ifindex = 0;
#endif /* SUNOS_5 */
#else /* neither IP_PKTINFO nor IP_RECVIF, broken */
#warning "getsockopt_ipv4_pktinfo_ifindex: dont have PKTINFO or RECVIF"
#warning "things probably will be broken on this platform!"
/* XXX why not -1 - this is a failure condition. */
#else
/*
* Neither IP_PKTINFO nor IP_RECVIF defined - warn at compile time.
* XXX Decide if this is a core service, or if daemons have to cope.
* Since Solaris 8 and OpenBSD seem not to provide it, it seems that
* daemons have to cope.
*/
#warning "getsockopt_ipv4_ifindex: Neither IP_PKTINFO nor IP_RECVIF defined."
#warning "Some daemons may fail to operate correctly!"
ifindex = 0;
#endif /* IP_PKTINFO */
return ifindex;
}