Re: [PATCH 6/8] udp: Unify udp_sock_handler_splice() with udp_sock_handler()

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Dec 13, 2022 at 11:48:58PM +0100, Stefano Brivio wrote:
> 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.

Ok... I'm not sure what, if anything, you would like me to do about
it, however.

> 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).

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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