Re: [PATCH v6 08/12] dhcp/dhcpv6: Pass queue pair explicitly through DHCP send path

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

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On Fri, Jul 31, 2026 at 06:16:13PM +0200, Laurent Vivier wrote:
> Add a qpair parameter to dhcp(), dhcpv6(), and
> dhcpv6_send_ia_notonlink(), forwarding it to tap_udp4_send() and
> tap_udp6_send() instead of hardcoding QPAIR_DEFAULT.
> 
> No functional change.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  dhcp.c   |  6 +++---
>  dhcp.h   |  2 +-
>  dhcpv6.c | 15 ++++++++-------
>  dhcpv6.h |  2 +-
>  tap.c    |  4 ++--
>  5 files changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/dhcp.c b/dhcp.c
> index 1bd68ed5b87b..bc7f0a61ee7e 100644
> --- a/dhcp.c
> +++ b/dhcp.c
> @@ -296,11 +296,12 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len)
>  /**
>   * dhcp() - Check if this is a DHCP message, reply as needed
>   * @c:		Execution context
> + * @qpair:	Queue pair on which to send the reply
>   * @data:	Single packet with Ethernet buffer
>   *
>   * Return: 0 if it's not a DHCP message, 1 if handled, -1 on failure
>   */
> -int dhcp(const struct ctx *c, struct iov_tail *data)
> +int dhcp(const struct ctx *c, unsigned int qpair, struct iov_tail *data)
>  {
>  	char macstr[ETH_ADDRSTRLEN];
>  	size_t mlen, dlen, opt_len;
> @@ -477,8 +478,7 @@ int dhcp(const struct ctx *c, struct iov_tail *data)
>  	else
>  		dst = c->ip4.addr;
>  
> -	tap_udp4_send(c, QPAIR_DEFAULT, c->ip4.our_tap_addr, 67, dst, 68,
> -		      &reply, dlen);
> +	tap_udp4_send(c, qpair, c->ip4.our_tap_addr, 67, dst, 68, &reply, dlen);
>  
>  	return 1;
>  }
> diff --git a/dhcp.h b/dhcp.h
> index cd50c99b8856..6d034f0c58af 100644
> --- a/dhcp.h
> +++ b/dhcp.h
> @@ -6,7 +6,7 @@
>  #ifndef DHCP_H
>  #define DHCP_H
>  
> -int dhcp(const struct ctx *c, struct iov_tail *data);
> +int dhcp(const struct ctx *c, unsigned int qpair, struct iov_tail *data);
>  void dhcp_init(void);
>  
>  #endif /* DHCP_H */
> diff --git a/dhcpv6.c b/dhcpv6.c
> index 0986d6149515..7887fdc7895a 100644
> --- a/dhcpv6.c
> +++ b/dhcpv6.c
> @@ -370,13 +370,14 @@ notonlink:
>  /**
>   * dhcpv6_send_ia_notonlink() - Send NotOnLink status
>   * @c:			Execution context
> + * @qpair:		Queue pair on which to send the reply
>   * @caddr:		Source address of client message (reply destination)
>   * @ia_base:		Non-appropriate IA_NA or IA_TA base
>   * @client_id_base:	Client ID message option base
>   * @len:		Client ID length
>   * @xid:		Transaction ID for message exchange
>   */
> -static void dhcpv6_send_ia_notonlink(struct ctx *c,
> +static void dhcpv6_send_ia_notonlink(struct ctx *c, unsigned int qpair,
>  				     const struct in6_addr *caddr,
>  				     const struct iov_tail *ia_base,
>  				     const struct iov_tail *client_id_base,
> @@ -407,8 +408,8 @@ static void dhcpv6_send_ia_notonlink(struct ctx *c,
>  
>  	resp_not_on_link.hdr.xid = xid;
>  
> -	tap_udp6_send(c, QPAIR_DEFAULT, src, 547, caddr, 546, xid,
> -		      &resp_not_on_link, n);
> +	tap_udp6_send(c, qpair, src, 547, caddr, 546, xid, &resp_not_on_link,
> +		      n);
>  }
>  
>  /**
> @@ -544,13 +545,14 @@ static size_t dhcpv6_client_fqdn_fill(const struct iov_tail *data,
>  /**
>   * dhcpv6() - Check if this is a DHCPv6 message, reply as needed
>   * @c:		Execution context
> + * @qpair:	Queue pair on which to send the reply
>   * @data:	Single packet starting from UDP header
>   * @saddr:	Source IPv6 address of original message
>   * @daddr:	Destination IPv6 address of original message
>   *
>   * Return: 0 if it's not a DHCPv6 message, 1 if handled, -1 on failure
>   */
> -int dhcpv6(struct ctx *c, struct iov_tail *data,
> +int dhcpv6(struct ctx *c, unsigned int qpair, struct iov_tail *data,
>  	   const struct in6_addr *saddr, const struct in6_addr *daddr)
>  {
>  	const struct opt_server_id *server_id = NULL;
> @@ -630,7 +632,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data,
>  
>  		if (dhcpv6_ia_notonlink(data, &c->ip6.addr)) {
>  
> -			dhcpv6_send_ia_notonlink(c, saddr, data,
> +			dhcpv6_send_ia_notonlink(c, qpair, saddr, data,
>  						 &client_id_base,
>  						 ntohs(client_id->l),
>  						 mh->xid);
> @@ -682,8 +684,7 @@ int dhcpv6(struct ctx *c, struct iov_tail *data,
>  
>  	resp.hdr.xid = mh->xid;
>  
> -	tap_udp6_send(c, QPAIR_DEFAULT, src, 547, saddr, 546, mh->xid, &resp,
> -		      n);
> +	tap_udp6_send(c, qpair, src, 547, saddr, 546, mh->xid, &resp, n);
>  	c->ip6.addr_seen = c->ip6.addr;
>  
>  	return 1;
> diff --git a/dhcpv6.h b/dhcpv6.h
> index 1015a1a7d3e3..e6cec5d0245e 100644
> --- a/dhcpv6.h
> +++ b/dhcpv6.h
> @@ -6,7 +6,7 @@
>  #ifndef DHCPV6_H
>  #define DHCPV6_H
>  
> -int dhcpv6(struct ctx *c, struct iov_tail *data,
> +int dhcpv6(struct ctx *c, unsigned int qpair, struct iov_tail *data,
>  	   const struct in6_addr *saddr, const struct in6_addr *daddr);
>  void dhcpv6_init(const struct ctx *c);
>  
> diff --git a/tap.c b/tap.c
> index 61d18ee161b1..84ac111d7a11 100644
> --- a/tap.c
> +++ b/tap.c
> @@ -802,7 +802,7 @@ resume:
>  			struct iov_tail eh_data;
>  
>  			packet_get(pool_tap4, i, &eh_data);
> -			if (dhcp(c, &eh_data))
> +			if (dhcp(c, qpair, &eh_data))
>  				continue;
>  		}
>  
> @@ -1048,7 +1048,7 @@ resume:
>  		if (proto == IPPROTO_UDP) {
>  			struct iov_tail uh_data = data;
>  
> -			if (dhcpv6(c, &uh_data, saddr, daddr))
> +			if (dhcpv6(c, qpair, &uh_data, saddr, daddr))
>  				continue;
>  		}
>  
> -- 
> 2.54.0
> 

-- 
David Gibson (he or they)	| 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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