Introduce a new helper to write data in a chain of mbufs,
spreading it in the segments.
Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
---
app/test/test_mbuf.c | 21 +++++++++++++++
lib/librte_mbuf/rte_mbuf.c | 44 +++++++++++++++++++++++++++++++
lib/librte_mbuf/rte_mbuf.h | 50 ++++++++++++++++++++++++++++++++++++
lib/librte_mbuf/rte_mbuf_version.map | 6 +++++
4 files changed, 121 insertions(+)
diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
index 7656a4d..5f1bc5d 100644
--- a/app/test/test_mbuf.c
+++ b/app/test/test_mbuf.c
@@ -335,6 +335,10 @@ testclone_testupdate_testdetach(void)
struct rte_mbuf *clone2 = NULL;
struct rte_mbuf *m2 = NULL;
unaligned_uint32_t *data;
+ uint32_t magic = MAGIC_DATA;
+ uint32_t check_data[2];
+
+ memset(check_data, 0, sizeof(check_data));
/* alloc a mbuf */
m = rte_pktmbuf_alloc(pktmbuf_pool);
@@ -421,6 +425,8 @@ testclone_testupdate_testdetach(void)
if (m2 == NULL)
GOTO_FAIL("cannot allocate m2");
rte_pktmbuf_append(m2, sizeof(uint32_t));
+ if (rte_pktmbuf_write(m2, 0, sizeof(uint32_t), &magic) < 0)
+ GOTO_FAIL("cannot write data in m2");
rte_pktmbuf_chain(m2, clone);
clone = NULL;
@@ -430,6 +436,21 @@ testclone_testupdate_testdetach(void)
rte_pktmbuf_pkt_len(m2) - sizeof(uint32_t)) == 0)
GOTO_FAIL("m2 data should be marked as shared");
+ /* check data content */
+ data = rte_pktmbuf_read(m2, 0, sizeof(uint32_t), check_data);
+ if (data == NULL)
+ GOTO_FAIL("cannot read data");
+ if (*data != MAGIC_DATA)
+ GOTO_FAIL("invalid data");
+ if (data == check_data)
+ GOTO_FAIL("data should not have been copied");
+ data = rte_pktmbuf_read(m2, 0, sizeof(uint32_t) * 2, check_data);
+ if (data == NULL)
+ GOTO_FAIL("cannot read data");
+ if (data[0] != MAGIC_DATA || data[1] != MAGIC_DATA)
+ GOTO_FAIL("invalid data");
+ if (data != check_data)
+ GOTO_FAIL("data should have been copied");
/* free mbuf */
rte_pktmbuf_free(m);
m = NULL;
diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index b31958e..ed56193 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -298,6 +298,50 @@ void *__rte_pktmbuf_read(const struct rte_mbuf *m,
uint32_t off,
return buf;
}
+/* write len data bytes in a mbuf at specified offset (internal) */
+int
+__rte_pktmbuf_write(const struct rte_mbuf *m, uint32_t off,
+ uint32_t len, const void *buf)
+{
+ const struct rte_mbuf *seg = m;
+ uint32_t buf_off = 0, copy_len;
+ char *dst;
+
+ if (off + len > rte_pktmbuf_pkt_len(m))
+ return -1;
+
+ while (off >= rte_pktmbuf_data_len(seg)) {
+ off -= rte_pktmbuf_data_len(seg);
+ seg = seg->next;
+ }
+
+ dst = rte_pktmbuf_mtod_offset(seg, char *, off);
+ if (buf == dst)
+ return 0;
+
+ if (off + len <= rte_pktmbuf_data_len(seg)) {
+ RTE_ASSERT(!rte_pktmbuf_is_shared(seg));
+ rte_memcpy(dst, buf, len);
+ return 0;
+ }
+
+ /* copy data in several segments */
+ while (len > 0) {
+ RTE_ASSERT(!rte_pktmbuf_is_shared(seg));
+ copy_len = rte_pktmbuf_data_len(seg) - off;
+ if (copy_len > len)
+ copy_len = len;
+ dst = rte_pktmbuf_mtod_offset(seg, char *, off);
+ rte_memcpy(dst, (const char *)buf + buf_off, copy_len);
+ off = 0;
+ buf_off += copy_len;
+ len -= copy_len;
+ seg = seg->next;
+ }
+
+ return 0;
+}
+
/*
* Get the name of a RX offload flag. Must be kept synchronized with flag
* definitions in rte_mbuf.h.
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index cd77a56..e898d25 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1678,6 +1678,56 @@ static inline void *rte_pktmbuf_read(const struct
rte_mbuf *m,
}
/**
+ * @internal used by rte_pktmbuf_write().
+ */
+int __rte_pktmbuf_write(const struct rte_mbuf *m, uint32_t off,
+ uint32_t len, const void *buf);
+
+/**
+ * Write len data bytes in a mbuf at specified offset.
+ *
+ * If the mbuf is contiguous between off and off+len, rte_memcpy() is
+ * called. Else, it will split the data in the segments.
+ *
+ * The caller must ensure that all destination segments are writable
+ * (not shared).
+ *
+ * If the destination pointer in the mbuf is the same than the source
+ * buffer, the function do nothing and is successful.
+ *
+ * If the mbuf is too small, the function fails.
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param off
+ * The offset of the data in the mbuf.
+ * @param len
+ * The amount of bytes to read.
+ * @param buf
+ * The buffer where data is copied if it is not contiguous in mbuf
+ * data. Its length should be at least equal to the len parameter.
+ * @return
+ * - (0) on success (data is updated in the mbuf)
+ * - (-1) on error: mbuf is too small or not writable
+ */
+static inline int rte_pktmbuf_write(const struct rte_mbuf *m,
+ uint32_t off, uint32_t len, const void *buf)
+{
+ char *dst = rte_pktmbuf_mtod_offset(m, char *, off);
+
+ if (buf == dst)
+ return 0;
+
+ if (off + len <= rte_pktmbuf_data_len(m)) {
+ RTE_ASSERT(!rte_pktmbuf_is_shared(m));
+ rte_memcpy(dst, buf, len);
+ return 0;
+ }
+
+ return __rte_pktmbuf_write(m, off, len, buf);
+}
+
+/**
* Chain an mbuf to another, thereby creating a segmented packet.
*
* Note: The implementation will do a linear walk over the segments to find
diff --git a/lib/librte_mbuf/rte_mbuf_version.map
b/lib/librte_mbuf/rte_mbuf_version.map
index 6e2ea84..b2c057e 100644
--- a/lib/librte_mbuf/rte_mbuf_version.map
+++ b/lib/librte_mbuf/rte_mbuf_version.map
@@ -35,3 +35,9 @@ DPDK_16.11 {
rte_get_tx_ol_flag_list;
} DPDK_2.1;
+
+DPDK_17.02 {
+ global:
+
+ __rte_pktmbuf_write;
+} DPDK_16.11;
--
2.8.1
