[dpdk-dev] [PATCH v2] doc: announce API changes for Windows compatibility
Dmitry Kozlyuk
dmitry.kozliuk at gmail.com
Thu Mar 11 00:54:21 CET 2021
Windows socket headers define `s_addr`, `min`, and `max` macros which
break structure definitions containing fields with one of these names.
Undefining those macros would break some consumers as well.
Example 1:
#include <winsock2.h>
#include <rte_ether.h>
struct in_addr addr;
/* addr.s_addr = 0; ERROR: s_addr undefined by DPDK */
Example 2:
#include <rte_ether.h>
#include <winsock2.h>
struct rte_ether_hdr eh;
/* eh.s_addr.addr_bytes[0] = 0; ERROR: `addr_s` is a macro */
It is proposed to rename the conflicting fields on DPDK side,
because Win32 API has wider use and is slower and harder to change.
New names are left unspecified, open suggestions:
* `struct rte_ether_hdr` (by Stephen Hemminger):
* `s_addr` -> `ether_shost`
* `d_addr` -> `ether_dhost` (for consistency)
* `struct rte_param_log2_range`, `struct rte_crypto_param_range`:
* `min` -> `minimum`
* `max` -> `maximum`
For `s_addr`, a workaround is possible to use it until 21.11.
For `min` and `max`, no workaround seems available. If cryptodev or
compressdev is going to be enabled on Windows before 21.11, the only
option seems to use a new name on Windows (using #ifdef).
Workaround for `s_addr` is to define `struct rte_ether_hdr`
in such a away that it can be used with or without `s_addr` macro
(as defined on Windows):
#pragma push_macro("s_addr")
#ifdef s_addr
#undef s_addr
#endif
struct rte_ether_hdr {
struct rte_ether_addr d_addr; /**< Destination address. */
RTE_STD_C11
union {
struct rte_ether_addr s_addr; /**< Source address. */
struct {
struct rte_ether_addr S_un;
/**< MUST NOT be used directly, only via s_addr */
} S_addr;
/**< MUST NOT be used directly, only via s_addr */
};
uint16_t ether_type; /**< Frame type. */
} __rte_aligned(2);
#pragma pop_macro("s_addr")
Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk at gmail.com>
---
v2: * Propose to rename all problematic fields identified so far.
* Leave future names unspecified, no need to promise now.
* Propose better names for MAC addresses (Stephen Hemminger).
Thread about `s_addr` workaround:
https://mails.dpdk.org/archives/dev/2021-March/200700.html
Tyler Retzlaff confirmed offline that Microsoft took similar approach.
doc/guides/rel_notes/deprecation.rst | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 64629e0641..854618f091 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -130,3 +130,12 @@ Deprecation Notices
* cmdline: ``cmdline`` structure will be made opaque to hide platform-specific
content. On Linux and FreeBSD, supported prior to DPDK 20.11,
original structure will be kept until DPDK 21.11.
+
+* net: ``s_addr`` and ``d_addr`` fields of ``rte_ether_hdr`` structure
+ will be renamed in DPDK 20.11 to avoid conflict with Windows Sockets headers.
+
+* compressdev: ``min`` and ``max`` fields of ``rte_param_log2_range`` structure
+ will be renamed in DPDK 20.11 to avoid conflict with Windows Sockets headers.
+
+* cryptodev: ``min`` and ``max`` fields of ``rte_crypto_param_range`` structure
+ will be renamed in DPDK 20.11 to avoid conflict with Windows Sockets headers.
--
2.29.2
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