Re: [dpdk-dev] [PATCH v2 4/6] net/pcap: add libpcap wrappers

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/3/2021 4:32 PM, Dmitry Kozlyuk wrote:
> 2021-03-02 11:22, Nick Connolly:
>>> Is posix_memalign() used more extensively in SPDK? In DPDK, it's 2 PMDs:
>> Yes, there are about 80 references. A lot are in ISA-L where they are
>> #defined to _aligned_malloc and can be ignored, but there still several
>> in the rest of the code.
> 
> I think portable code should try sticking to C11 aligned_malloc().
> BTW, _aligned_malloc (with "_") only supports power-of-2 alignment.
> 
> There's a related passage in MSVC blog:
> 
> 	Due to the nature of the Windows heap, aligned_alloc support is
> 	missing. The alternative is to use _aligned_malloc.
> 
> https://devblogs.microsoft.com/cppblog/c11-and-c17-standard-support-arriving-in-msvc/
> 
>>>>     * Sockets are unfortunately specified as using close(). This is
>>>>       probably easy to address by rte_ wrapping all socket calls.
>>> Which public DPDK APIs operate on sockets?
>>> I don't like the idea of wrapping APIs like sockets or files.
>> I'm not sure about use in public APIs - I'd hope none do. I was thinking
>> about 'internal' use.
> 
> This is important (even more so for SPDK, I suspect), however, I'd like to
> focus on public API first.
> 
>>> I drafted what I was talking about: adding address types and removing shims:
>>>
>>> * librte_net/rte_ip.h then includes <netinet/ip.h> or <ws2tcpip.h>
>>>     conditionally for AF_xxx, IPPROTO_xxx, and a few other constants.
>>>     That's probably OK, there are similar places for Linux/FreeBSD differences,
>>>     e.g. in <rte_endian.h>.
>>>
>>> * Some IPPROTO_xxx constants are missing on Windows, so rte_ip.h has to
>>>     provide them. I hope Mirosoft will add them to system headers one day.
>>>
>>> * It affects cmdline (mostly), ethdev, security, crypto/dpaax.
>> Sounds good - well done!
> 
> ...or not :)
> 
> 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. */