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flow: Move functions for dealing with wildcard bit counts to ofp-util.

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These functions are really OpenFlow-specific, and they will not be used
directly by the flow code soon, so move them to ofp-util.
This commit is contained in:
Ben Pfaff
2010-11-22 10:09:18 -08:00
parent 00561f415c
commit 0596e89755
6 changed files with 66 additions and 45 deletions
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43
lib/ofp-util.c
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@@ -32,6 +32,41 @@ VLOG_DEFINE_THIS_MODULE(ofp_util);
* in the peer and so there's not much point in showing a lot of them. */
static struct vlog_rate_limit bad_ofmsg_rl = VLOG_RATE_LIMIT_INIT(1, 5);
/* Given the wildcard bit count in the least-significant 6 of 'wcbits', returns
* an IP netmask with a 1 in each bit that must match and a 0 in each bit that
* is wildcarded.
*
* The bits in 'wcbits' are in the format used in enum ofp_flow_wildcards: 0
* is exact match, 1 ignores the LSB, 2 ignores the 2 least-significant bits,
* ..., 32 and higher wildcard the entire field. This is the *opposite* of the
* usual convention where e.g. /24 indicates that 8 bits (not 24 bits) are
* wildcarded. */
ovs_be32
ofputil_wcbits_to_netmask(int wcbits)
{
wcbits &= 0x3f;
return wcbits < 32 ? htonl(~((1u << wcbits) - 1)) : 0;
}
/* Given the IP netmask 'netmask', returns the number of bits of the IP address
* that it wildcards. 'netmask' must be a CIDR netmask (see ip_is_cidr()). */
int
ofputil_netmask_to_wcbits(ovs_be32 netmask)
{
assert(ip_is_cidr(netmask));
#if __GNUC__ >= 4
return netmask == htonl(0) ? 32 : __builtin_ctz(ntohl(netmask));
#else
int wcbits;
for (wcbits = 32; netmask; wcbits--) {
netmask &= netmask - 1;
}
return wcbits;
#endif
}
/* Returns a transaction ID to use for an outgoing OpenFlow message. */
static ovs_be32
alloc_xid(void)
@@ -747,10 +782,10 @@ normalize_match(struct ofp_match *m)
m->tp_src = m->tp_dst = 0;
}
if (wc & OFPFW_NW_SRC_MASK) {
m->nw_src &= flow_nw_bits_to_mask(wc, OFPFW_NW_SRC_SHIFT);
m->nw_src &= ofputil_wcbits_to_netmask(wc >> OFPFW_NW_SRC_SHIFT);
}
if (wc & OFPFW_NW_DST_MASK) {
m->nw_dst &= flow_nw_bits_to_mask(wc, OFPFW_NW_DST_SHIFT);
m->nw_dst &= ofputil_wcbits_to_netmask(wc >> OFPFW_NW_DST_SHIFT);
}
if (wc & OFPFW_NW_TOS) {
m->nw_tos = 0;
@@ -762,10 +797,10 @@ normalize_match(struct ofp_match *m)
m->nw_proto = 0;
}
if (wc & OFPFW_NW_SRC_MASK) {
m->nw_src &= flow_nw_bits_to_mask(wc, OFPFW_NW_SRC_SHIFT);
m->nw_src &= ofputil_wcbits_to_netmask(wc >> OFPFW_NW_SRC_SHIFT);
}
if (wc & OFPFW_NW_DST_MASK) {
m->nw_dst &= flow_nw_bits_to_mask(wc, OFPFW_NW_DST_SHIFT);
m->nw_dst &= ofputil_wcbits_to_netmask(wc >> OFPFW_NW_DST_SHIFT);
}
m->tp_src = m->tp_dst = m->nw_tos = 0;
} else {