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From: Stefano Brivio <sbrivio@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH 6/8] udp: Unify udp_sock_handler_splice() with udp_sock_handler()
Date: Tue, 13 Dec 2022 23:48:58 +0100	[thread overview]
Message-ID: <20221213234858.474602c1@elisabeth> (raw)
In-Reply-To: <20221205081425.2614425-7-david@gibson.dropbear.id.au>

On Mon,  5 Dec 2022 19:14:23 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> These two functions now have a very similar structure, and their first
> part (calling recvmmsg()) is functionally identical.  So, merge the two
> functions into one.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  udp.c | 86 +++++++++++++++++++----------------------------------------
>  1 file changed, 28 insertions(+), 58 deletions(-)
> 
> diff --git a/udp.c b/udp.c
> index 7c601cc..6ccfe8c 100644
> --- a/udp.c
> +++ b/udp.c
> @@ -590,52 +590,6 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start, unsigned n,
>  	sendmmsg(s, mmh_send + start, n, MSG_NOSIGNAL);
>  }
>  
> -/**
> - * udp_sock_handler_splice() - Handler for socket mapped to "spliced" connection
> - * @c:		Execution context
> - * @ref:	epoll reference
> - * @events:	epoll events bitmap
> - * @now:	Current timestamp
> - */
> -static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
> -				    uint32_t events, const struct timespec *now)
> -{
> -	in_port_t dst = ref.r.p.udp.udp.port;
> -	int v6 = ref.r.p.udp.udp.v6, n, i, m;
> -	struct mmsghdr *mmh_recv;
> -
> -	if (!(events & EPOLLIN))
> -		return;
> -
> -	if (v6)
> -		mmh_recv = udp6_l2_mh_sock;
> -	else
> -		mmh_recv = udp4_l2_mh_sock;
> -
> -	n = recvmmsg(ref.r.s, mmh_recv, UDP_MAX_FRAMES, 0, NULL);
> -
> -	if (n <= 0)
> -		return;
> -
> -	if (v6)
> -		udp_localname6.sin6_port = htons(dst);
> -	else
> -		udp_localname4.sin_port = htons(dst);
> -
> -	for (i = 0; i < n; i += m) {
> -		in_port_t src = sa_port(v6, mmh_recv[i].msg_hdr.msg_name);
> -
> -		for (m = 1; i + m < n; m++) {
> -			void *mname = mmh_recv[i + m].msg_hdr.msg_name;
> -			if (sa_port(v6, mname) != src)
> -				break;
> -		}
> -
> -		udp_splice_sendfrom(c, i, m, src, dst, v6, ref.r.p.udp.udp.ns,
> -				    ref.r.p.udp.udp.orig, now);
> -	}
> -}
> -
>  /**
>   * udp_update_hdr4() - Update headers for one IPv4 datagram
>   * @c:		Execution context
> @@ -945,27 +899,43 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t events,
>  {
>  	in_port_t dstport = ref.r.p.udp.udp.port;
>  	bool v6 = ref.r.p.udp.udp.v6;
> -	struct mmsghdr *sock_mmh;
> +	struct mmsghdr *mmh_recv;
> +	unsigned int i, m;
>  	ssize_t n;
>  
> -	if (events == EPOLLERR)
> +	if (!(events & EPOLLIN))

Pre-existing, unrelated issue, but this reminds me: we don't handle
socket errors here, and while udp_timer_one() will drop any sockets we
created, eventually, it would probably be better to act right away.

Not that I have in mind a valid example of an error on UDP sockets,
except perhaps if the interface goes down (but we'll handle that
separately).

-- 
Stefano


  reply	other threads:[~2022-12-13 22:49 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-05  8:14 [PATCH 0/8] Don't use additional sockets for receiving "spliced" UDP communications David Gibson
2022-12-05  8:14 ` [PATCH 1/8] udp: Move sending pasta tap frames to the end of udp_sock_handler() David Gibson
2022-12-05  8:14 ` [PATCH 2/8] udp: Split sending to passt tap interface into separate function David Gibson
2022-12-05  8:14 ` [PATCH 3/8] udp: Split receive from preparation and send in udp_sock_handler() David Gibson
2022-12-05  8:14 ` [PATCH 4/8] udp: Receive multiple datagrams at once on the pasta sock->tap path David Gibson
2022-12-13 22:48   ` Stefano Brivio
2022-12-14  1:42     ` David Gibson
2022-12-14 10:35       ` Stefano Brivio
2022-12-20 10:42         ` Stefano Brivio
2022-12-21  6:00           ` David Gibson
2022-12-22  2:37             ` Stefano Brivio
2023-01-04  0:08             ` Stefano Brivio
2023-01-04  4:53               ` David Gibson
2022-12-05  8:14 ` [PATCH 5/8] udp: Pre-populate msg_names with local address David Gibson
2022-12-13 22:48   ` Stefano Brivio
2022-12-14  1:22     ` David Gibson
2022-12-05  8:14 ` [PATCH 6/8] udp: Unify udp_sock_handler_splice() with udp_sock_handler() David Gibson
2022-12-13 22:48   ` Stefano Brivio [this message]
2022-12-14  1:19     ` David Gibson
2022-12-14 10:35       ` Stefano Brivio
2022-12-05  8:14 ` [PATCH 7/8] udp: Decide whether to "splice" per datagram rather than per socket David Gibson
2022-12-13 22:49   ` Stefano Brivio
2022-12-14  1:47     ` David Gibson
2022-12-14 10:35       ` Stefano Brivio
2022-12-15  0:33         ` David Gibson
2022-12-05  8:14 ` [PATCH 8/8] udp: Don't use separate sockets to listen for spliced packets David Gibson
2022-12-06  6:45 ` [PATCH 0/8] Don't use additional sockets for receiving "spliced" UDP communications Stefano Brivio
2022-12-06  6:46   ` Stefano Brivio

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