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ofp-actions: Only set defined bits when encoding "load" actions.

Browse Source 
Commit 7eb4b1f1d7 ("ofp-actions: Support OF1.5 (draft) masked
Set-Field, merge with reg_load.") introduced a bug in that a set_field
action that set an entire field would be translated incorrectly to
reg_load, if the field being set only occupied a portion of the bytes that
it contains.  For example, an MPLS label is 20 bits but has a 4-byte field,
which meant that a set_field would get translated into a reg_load that
wrote all 32 bits; in turn, the receiver of that reg_load would reject it
because it was attempting to set invalid bits (the top 12 bits).

This commit fixes the problem by omitting invalid bits when encoding a
reg_load action.

Reported-by: Pravin Shelar <pshelar@nicira.com>
Tested-by: Pravin Shelar <pshelar@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
This commit is contained in:
Ben Pfaff
2014-12-04 14:31:56 -08:00
parent b2fc6a7447
commit fa07848939
2 changed files with 23 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lib/ofp-actions.c
View File

@@ -2183,16 +2183,17 @@ static bool
next_load_segment(const struct ofpact_set_field *sf,
struct mf_subfield *dst, uint64_t *value)
{
int w = sf->field->n_bytes;
int n_bits = sf->field->n_bits;
int n_bytes = sf->field->n_bytes;
int start = dst->ofs + dst->n_bits;
if (start < 8 * w) {
if (start < n_bits) {
dst->field = sf->field;
dst->ofs = bitwise_scan(&sf->mask, w, 1, start, 8 * w);
if (dst->ofs < 8 * w) {
dst->n_bits = bitwise_scan(&sf->mask, w, 0, dst->ofs + 1,
MIN(dst->ofs + 64, 8 * w)) - dst->ofs;
*value = bitwise_get(&sf->value, w, dst->ofs, dst->n_bits);
dst->ofs = bitwise_scan(&sf->mask, n_bytes, 1, start, n_bits);
if (dst->ofs < n_bits) {
dst->n_bits = bitwise_scan(&sf->mask, n_bytes, 0, dst->ofs + 1,
MIN(dst->ofs + 64, n_bits)) - dst->ofs;
*value = bitwise_get(&sf->value, n_bytes, dst->ofs, dst->n_bits);
return true;
}
}