MINOR: ncbuf: define various insertion modes
Define three different ways to proceed insertion. This configures how
overlapping data is treated.
- NCB_ADD_PRESERVE : in this mode, old data are kept during insertion.
- NCB_ADD_OVERWRT : new data will overwrite old ones.
- NCB_ADD_COMPARE : this mode adds a new test in check stage. The
overlapping old and new data must be identical or else the insertion
is not conducted. An error NCB_RET_DATA_REJ is used in this case.
The mode is specified with a new argument to ncb_add() function.
diff --git a/include/haproxy/ncbuf-t.h b/include/haproxy/ncbuf-t.h
index 05bebe6..fdeb58b 100644
--- a/include/haproxy/ncbuf-t.h
+++ b/include/haproxy/ncbuf-t.h
@@ -91,6 +91,14 @@
NCB_RET_OK = 0, /* no error */
NCB_RET_GAP_SIZE, /* operation would create a too small gap */
+ NCB_RET_DATA_REJ, /* operation would overwrite data with different one */
+};
+
+/* Define how insert is conducted in regards with already stored data. */
+enum ncb_add_mode {
+ NCB_ADD_PRESERVE, /* keep the already stored data and only insert in gaps */
+ NCB_ADD_OVERWRT, /* overwrite old data with new ones */
+ NCB_ADD_COMPARE, /* compare before insert : if new data are different do not proceed */
};
#endif /* _HAPROXY_NCBUF_T_H */
diff --git a/include/haproxy/ncbuf.h b/include/haproxy/ncbuf.h
index c935c1e..a13dd50 100644
--- a/include/haproxy/ncbuf.h
+++ b/include/haproxy/ncbuf.h
@@ -19,6 +19,6 @@
ncb_sz_t ncb_data(const struct ncbuf *buf, ncb_sz_t offset);
enum ncb_ret ncb_add(struct ncbuf *buf, ncb_sz_t off,
- const char *data, ncb_sz_t len);
+ const char *data, ncb_sz_t len, enum ncb_add_mode mode);
#endif /* _HAPROXY_NCBUF_H */
diff --git a/src/ncbuf.c b/src/ncbuf.c
index 5922407..db08649 100644
--- a/src/ncbuf.c
+++ b/src/ncbuf.c
@@ -207,13 +207,16 @@
/* Simulate insertion in <buf> of <data> of length <len> at offset <off>. This
* ensures that minimal block size are respected for newly formed gaps. <blk>
- * must be the block where the insert operation begins.
+ * must be the block where the insert operation begins. If <mode> is
+ * NCB_ADD_COMPARE, old and new overlapped data are compared to validate the
+ * insertion.
*
* Returns NCB_RET_OK if insertion can proceed.
*/
static enum ncb_ret ncb_check_insert(const struct ncbuf *buf,
struct ncb_blk blk, ncb_sz_t off,
- const char *data, ncb_sz_t len)
+ const char *data, ncb_sz_t len,
+ enum ncb_add_mode mode)
{
ncb_sz_t off_blk = ncb_blk_off(blk, off);
ncb_sz_t to_copy;
@@ -239,6 +242,24 @@
if (gap_sz < NCB_GAP_MIN_SZ && !ncb_blk_is_last(buf, blk))
return NCB_RET_GAP_SIZE;
}
+ else if (!(blk.flag & NCB_BK_F_GAP) && mode == NCB_ADD_COMPARE) {
+ /* Compare memory of data block in NCB_ADD_COMPARE mode. */
+ const ncb_sz_t off_blk = ncb_blk_off(blk, off);
+ char *st = ncb_peek(buf, off);
+
+ to_copy = MIN(left, blk.sz - off_blk);
+ if (st + to_copy > ncb_wrap(buf)) {
+ const ncb_sz_t sz1 = ncb_wrap(buf) - st;
+ if (memcmp(st, data, sz1))
+ return NCB_RET_DATA_REJ;
+ if (memcmp(ncb_orig(buf), data + sz1, to_copy - sz1))
+ return NCB_RET_DATA_REJ;
+ }
+ else {
+ if (memcmp(st, data, to_copy))
+ return NCB_RET_DATA_REJ;
+ }
+ }
left -= to_copy;
data += to_copy;
@@ -252,13 +273,15 @@
/* Fill new <data> of length <len> inside an already existing data <blk> at
* offset <off>. Offset is relative to <blk> so it cannot be greater than the
- * block size.
+ * block size. <mode> specifies if old data are preserved or overwritten.
*/
static ncb_sz_t ncb_fill_data_blk(const struct ncbuf *buf,
struct ncb_blk blk, ncb_sz_t off,
- const char *data, ncb_sz_t len)
+ const char *data, ncb_sz_t len,
+ enum ncb_add_mode mode)
{
const ncb_sz_t to_copy = MIN(len, blk.sz - off);
+ char *ptr = NULL;
BUG_ON_HOT(off > blk.sz);
/* This can happens due to previous ncb_blk_find() usage. In this
@@ -267,6 +290,19 @@
if (off == blk.sz)
return 0;
+ if (mode == NCB_ADD_OVERWRT) {
+ ptr = ncb_peek(buf, blk.off + off);
+
+ if (ptr + to_copy >= ncb_wrap(buf)) {
+ const ncb_sz_t sz1 = ncb_wrap(buf) - ptr;
+ memcpy(ptr, data, sz1);
+ memcpy(ncb_orig(buf), data + sz1, to_copy - sz1);
+ }
+ else {
+ memcpy(ptr, data, to_copy);
+ }
+ }
+
return to_copy;
}
@@ -438,9 +474,11 @@
*
* Returns NCB_RET_OK on success. On error the following codes are returned :
* - NCB_RET_GAP_SIZE : cannot add data because the gap formed is too small
+ * - NCB_RET_DATA_REJ : old data would be overwritten by different ones in
+ * NCB_ADD_COMPARE mode.
*/
enum ncb_ret ncb_add(struct ncbuf *buf, ncb_sz_t off,
- const char *data, ncb_sz_t len)
+ const char *data, ncb_sz_t len, enum ncb_add_mode mode)
{
struct ncb_blk blk;
ncb_sz_t left = len;
@@ -456,7 +494,7 @@
blk = ncb_blk_find(buf, off);
/* Check if insertion is possible. */
- ret = ncb_check_insert(buf, blk, off, data, len);
+ ret = ncb_check_insert(buf, blk, off, data, len, mode);
if (ret != NCB_RET_OK)
return ret;
@@ -503,7 +541,7 @@
}
}
else {
- done = ncb_fill_data_blk(buf, blk, off_blk, data, left);
+ done = ncb_fill_data_blk(buf, blk, off_blk, data, left, mode);
}
BUG_ON_HOT(done > blk.sz || done > left);