Re: [PATCH 03/11] udp: Pass full epoll reference through more of sock handler path

[Stefano Brivio <sbrivio@redhat.com>]

On Thu,  4 Jul 2024 14:58:27 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> udp_buf_sock_handler() takes the epoll reference from the receiving socket,
> and passes the UDP relevant part on to several other functions.  Future
> changes are going to need several different epoll types for UDP, and to
> pass that information through to some of those functions.  To avoid extra
> noise in the patches making the real changes, change those functions now
> to take the full epoll reference, rather than just the UDP part.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  udp.c | 63 +++++++++++++++++++++++++++++++----------------------------
>  1 file changed, 33 insertions(+), 30 deletions(-)
> 
> diff --git a/udp.c b/udp.c
> index eadf4872..6301bda2 100644
> --- a/udp.c
> +++ b/udp.c
> @@ -477,25 +477,26 @@ static int udp_splice_new_ns(void *arg)
>  
>  /**
>   * udp_mmh_splice_port() - Is source address of message suitable for splicing?
> - * @uref:	UDP epoll reference for incoming message's origin socket
> + * @ref:	Epoll reference for incoming message's origin socket

Nit: in 1/11 (and later in this patch), this is "epoll" instead, which
looks more correct to me as it's a proper noun, but not capitalised.
Same for udp_update_hdr6().

>   * @mmh:	mmsghdr of incoming message
>   *
>   * Return: if source address of message in @mmh refers to localhost (127.0.0.1
>   *         or ::1) its source port (host order), otherwise -1.
>   */
> -static int udp_mmh_splice_port(union udp_epoll_ref uref,
> -			       const struct mmsghdr *mmh)
> +static int udp_mmh_splice_port(union epoll_ref ref, const struct mmsghdr *mmh)
>  {
>  	const struct sockaddr_in6 *sa6 = mmh->msg_hdr.msg_name;
>  	const struct sockaddr_in *sa4 = mmh->msg_hdr.msg_name;
>  
> -	if (!uref.splice)
> +	ASSERT(ref.type == EPOLL_TYPE_UDP);
> +
> +	if (!ref.udp.splice)
>  		return -1;
>  
> -	if (uref.v6 && IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
> +	if (ref.udp.v6 && IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr))
>  		return ntohs(sa6->sin6_port);
>  
> -	if (!uref.v6 && IN4_IS_ADDR_LOOPBACK(&sa4->sin_addr))
> +	if (!ref.udp.v6 && IN4_IS_ADDR_LOOPBACK(&sa4->sin_addr))
>  		return ntohs(sa4->sin_port);
>  
>  	return -1;
> @@ -507,7 +508,7 @@ static int udp_mmh_splice_port(union udp_epoll_ref uref,
>   * @start:	Index of first datagram in udp[46]_l2_buf
>   * @n:		Total number of datagrams in udp[46]_l2_buf pool
>   * @dst:	Datagrams will be sent to this port (on destination side)
> - * @uref:	UDP epoll reference for origin socket
> + * @ref:	epoll reference for origin socket
>   * @now:	Timestamp
>   *
>   * This consumes as many datagrams as are sendable via a single socket.  It
> @@ -518,7 +519,7 @@ static int udp_mmh_splice_port(union udp_epoll_ref uref,
>   * Return: Number of datagrams forwarded
>   */
>  static unsigned udp_splice_send(const struct ctx *c, size_t start, size_t n,
> -				in_port_t dst, union udp_epoll_ref uref,
> +				in_port_t dst, union epoll_ref ref,
>  				const struct timespec *now)
>  {
>  	in_port_t src = udp_meta[start].splicesrc;
> @@ -527,8 +528,9 @@ static unsigned udp_splice_send(const struct ctx *c, size_t start, size_t n,
>  	int s;
>  
>  	ASSERT(udp_meta[start].splicesrc >= 0);
> +	ASSERT(ref.type == EPOLL_TYPE_UDP);
>  
> -	if (uref.v6) {
> +	if (ref.udp.v6) {
>  		mmh_recv = udp6_l2_mh_sock;
>  		mmh_send = udp6_mh_splice;
>  		udp6_localname.sin6_port = htons(dst);
> @@ -544,27 +546,27 @@ static unsigned udp_splice_send(const struct ctx *c, size_t start, size_t n,
>  		if (++i >= n)
>  			break;
>  
> -		udp_meta[i].splicesrc = udp_mmh_splice_port(uref, &mmh_recv[i]);
> +		udp_meta[i].splicesrc = udp_mmh_splice_port(ref, &mmh_recv[i]);
>  	} while (udp_meta[i].splicesrc == src);
>  
> -	if (uref.pif == PIF_SPLICE) {
> +	if (ref.udp.pif == PIF_SPLICE) {
>  		src += c->udp.fwd_in.rdelta[src];
> -		s = udp_splice_init[uref.v6][src].sock;
> -		if (s < 0 && uref.orig)
> -			s = udp_splice_new(c, uref.v6, src, false);
> +		s = udp_splice_init[ref.udp.v6][src].sock;
> +		if (s < 0 && ref.udp.orig)
> +			s = udp_splice_new(c, ref.udp.v6, src, false);
>  
>  		if (s < 0)
>  			goto out;
>  
> -		udp_splice_ns[uref.v6][dst].ts = now->tv_sec;
> -		udp_splice_init[uref.v6][src].ts = now->tv_sec;
> +		udp_splice_ns[ref.udp.v6][dst].ts = now->tv_sec;
> +		udp_splice_init[ref.udp.v6][src].ts = now->tv_sec;
>  	} else {
> -		ASSERT(uref.pif == PIF_HOST);
> +		ASSERT(ref.udp.pif == PIF_HOST);
>  		src += c->udp.fwd_out.rdelta[src];
> -		s = udp_splice_ns[uref.v6][src].sock;
> -		if (s < 0 && uref.orig) {
> +		s = udp_splice_ns[ref.udp.v6][src].sock;
> +		if (s < 0 && ref.udp.orig) {
>  			struct udp_splice_new_ns_arg arg = {
> -				c, uref.v6, src, -1,
> +				c, ref.udp.v6, src, -1,
>  			};
>  
>  			NS_CALL(udp_splice_new_ns, &arg);
> @@ -573,8 +575,8 @@ static unsigned udp_splice_send(const struct ctx *c, size_t start, size_t n,
>  		if (s < 0)
>  			goto out;
>  
> -		udp_splice_init[uref.v6][dst].ts = now->tv_sec;
> -		udp_splice_ns[uref.v6][src].ts = now->tv_sec;
> +		udp_splice_init[ref.udp.v6][dst].ts = now->tv_sec;
> +		udp_splice_ns[ref.udp.v6][src].ts = now->tv_sec;
>  	}
>  
>  	sendmmsg(s, mmh_send + start, i - start, MSG_NOSIGNAL);
> @@ -716,7 +718,7 @@ static size_t udp_update_hdr6(const struct ctx *c,
>   * @start:	Index of first datagram in udp[46]_l2_buf pool
>   * @n:		Total number of datagrams in udp[46]_l2_buf pool
>   * @dstport:	Destination port number on destination side
> - * @uref:	UDP epoll reference for origin socket
> + * @ref:	Epoll reference for origin socket
>   * @now:	Current timestamp
>   *
>   * This consumes as many frames as are sendable via tap.  It requires that
> @@ -726,7 +728,7 @@ static size_t udp_update_hdr6(const struct ctx *c,
>   * Return: Number of frames sent via tap
>   */
>  static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
> -			     in_port_t dstport, union udp_epoll_ref uref,
> +			     in_port_t dstport, union epoll_ref ref,
>  			     const struct timespec *now)
>  {
>  	struct iovec (*tap_iov)[UDP_NUM_IOVS];
> @@ -734,8 +736,9 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
>  	size_t i = start;
>  
>  	ASSERT(udp_meta[start].splicesrc == -1);
> +	ASSERT(ref.type == EPOLL_TYPE_UDP);
>  
> -	if (uref.v6) {
> +	if (ref.udp.v6) {
>  		tap_iov = udp6_l2_iov_tap;
>  		mmh_recv = udp6_l2_mh_sock;
>  	} else {
> @@ -748,7 +751,7 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
>  		struct udp_meta_t *bm = &udp_meta[i];
>  		size_t l4len;
>  
> -		if (uref.v6) {
> +		if (ref.udp.v6) {
>  			l4len = udp_update_hdr6(c, &bm->ip6h,
>  						&bm->s_in.sa6, bp, dstport,
>  						udp6_l2_mh_sock[i].msg_len, now);
> @@ -766,7 +769,7 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
>  		if (++i >= n)
>  			break;
>  
> -		udp_meta[i].splicesrc = udp_mmh_splice_port(uref, &mmh_recv[i]);
> +		udp_meta[i].splicesrc = udp_mmh_splice_port(ref, &mmh_recv[i]);
>  	} while (udp_meta[i].splicesrc == -1);
>  
>  	tap_send_frames(c, &tap_iov[start][0], UDP_NUM_IOVS, i - start);
> @@ -823,12 +826,12 @@ void udp_buf_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t eve
>  	 * present).  So we fill in entry 0 before the loop, then udp_*_send()
>  	 * populate one entry past where they consume.
>  	 */
> -	udp_meta[0].splicesrc = udp_mmh_splice_port(ref.udp, mmh_recv);
> +	udp_meta[0].splicesrc = udp_mmh_splice_port(ref, mmh_recv);
>  	for (i = 0; i < n; i += m) {
>  		if (udp_meta[i].splicesrc >= 0)
> -			m = udp_splice_send(c, i, n, dstport, ref.udp, now);
> +			m = udp_splice_send(c, i, n, dstport, ref, now);
>  		else
> -			m = udp_tap_send(c, i, n, dstport, ref.udp, now);
> +			m = udp_tap_send(c, i, n, dstport, ref, now);
>  	}
>  }
>  

-- 
Stefano