[dpdk-dev] [PATCH v2 4/6] net/pcap: add libpcap wrappers
Dmitry Kozlyuk
dmitry.kozliuk at gmail.com
Wed Mar 3 19:19:20 CET 2021
2021-03-03 16:47, Ferruh Yigit:
> On 3/3/2021 4:32 PM, Dmitry Kozlyuk wrote:
[...]
> > If we can't help including <ws2tcpip.h>/<netinet/ip.h> from public headers,
> > might as well use `struct in_addr`, just replace `#include <netinet/ip.h>`
> > with `#include <rte_ip.h>` everywhere.
> >
> > The only remaining issue will be `s_addr` macro on Windows that conflicts with
> > `struct rte_ether_addr` field `s_addr`. I don't know a better solution than
> > renaming `s_addr` to `src_addr` in DPDK (OTOH, it will be consistent with
> > `struct rte_ipvX_hdr` field naming).
> >
> > Ferruh, what do you think?
> >
>
> No problem on the chosen name, that will work fine, but the 'struct
> rte_eth_addr' is public struct, we can't rename it without breaking the user
> applications.
>
> Still it is possible to rename public struct, but it is a long process, need to
> send a deprecation notice and wait for next LTS, 21.11.
>
> Ethernet header already has following, doesn't it help:
> #undef s_addr /* Defined in winsock2.h included in windows.h. */
It helps until you do the following:
#include <winsock2.h> /* #define s_addr S_un.S_addr */
#include <rte_ether.h> /* #undef s_addr */
struct in_addr a;
a.s_addr = 0; /* ERROR, `s_addr` has been defined to do that */
Or the following:
#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 */
If you swap include order in each case, it compiles, i.e . code is fragile.
Shims redefine `struct in_addr` and we're trying to get rid of them anyway.
Here's a solution that always works, however ugly it looks. It defines
`struct rte_ether_hdr` for Windows such that `s_addr` macro works for it if
defined. We can keep it until 21.11, then remove it and rename fields. In
return, we can remove networking shims and workarounds immediately.
`S_un.S_addr` part of `struct in_addr` is documented, and thus is unlikely to
ever change:
https://docs.microsoft.com/en-us/windows/win32/api/winsock2/ns-winsock2-in_addr
diff --git a/lib/librte_net/rte_ether.h b/lib/librte_net/rte_ether.h
index 060b63fc9..67d340bb2 100644
--- a/lib/librte_net/rte_ether.h
+++ b/lib/librte_net/rte_ether.h
@@ -23,10 +23,6 @@ extern "C" {
#include <rte_mbuf.h>
#include <rte_byteorder.h>
-#ifdef RTE_EXEC_ENV_WINDOWS /* Workaround conflict with rte_ether_hdr. */
-#undef s_addr /* Defined in winsock2.h included in windows.h. */
-#endif
-
#define RTE_ETHER_ADDR_LEN 6 /**< Length of Ethernet address. */
#define RTE_ETHER_TYPE_LEN 2 /**< Length of Ethernet type field. */
#define RTE_ETHER_CRC_LEN 4 /**< Length of Ethernet CRC. */
@@ -257,6 +253,8 @@ __rte_experimental
int
rte_ether_unformat_addr(const char *str, struct rte_ether_addr *eth_addr);
+#if !defined RTE_EXEC_ENV_WINDOWS || defined __DOXYGEN__
+
/**
* Ethernet header: Contains the destination address, source address
* and frame type.
@@ -267,6 +265,28 @@ struct rte_ether_hdr {
uint16_t ether_type; /**< Frame type. */
} __rte_aligned(2);
+#else
+
+#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;
+ } S_addr;
+ };
+ uint16_t ether_type; /**< Frame type. */
+} __rte_aligned(2);
+
+#pragma pop_macro("s_addr")
+#endif
+
/**
* Ethernet VLAN Header.
* Contains the 16-bit VLAN Tag Control Identifier and the Ethernet type
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