[PATCH v6 10/12] ndp: Pass queue pair explicitly through NDP send path

[Laurent Vivier <lvivier@redhat.com>]

Add a qpair parameter to ndp(), ndp_send(), ndp_na(), and ndp_ra(),
forwarding it to tap_icmp6_send() instead of hardcoding QPAIR_DEFAULT,
so solicited replies (NA to NS, RA to RS) go out on the same queue
pair the solicitation arrived on.

ndp_send_init_req(), ndp_unsolicited_na(), and ndp_timer() are
unsolicited, low-volume messages with no meaningful queue pair
context, so they hardcode QPAIR_DEFAULT internally.

No functional change.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 ndp.c | 33 +++++++++++++++++++--------------
 ndp.h |  2 +-
 tap.c |  2 +-
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/ndp.c b/ndp.c
index 6269cb38d93f..400cee3e926f 100644
--- a/ndp.c
+++ b/ndp.c
@@ -175,26 +175,28 @@ struct ndp_ns {
 /**
  * ndp_send() - Send an NDP message
  * @c:		Execution context
+ * @qpair:	Queue pair on which to send the message
  * @dst:	IPv6 address to send the message to
  * @buf:	ICMPv6 header + message payload
  * @l4len:	Length of message, including ICMPv6 header
  */
-static void ndp_send(const struct ctx *c, const struct in6_addr *dst,
-		     const void *buf, size_t l4len)
+static void ndp_send(const struct ctx *c, unsigned int qpair,
+		     const struct in6_addr *dst, const void *buf, size_t l4len)
 {
 	const struct in6_addr *src = &c->ip6.our_tap_ll;
 
-	tap_icmp6_send(c, QPAIR_DEFAULT, src, dst, buf, c->our_tap_mac, l4len);
+	tap_icmp6_send(c, qpair, src, dst, buf, c->our_tap_mac, l4len);
 }
 
 /**
  * ndp_na() - Send an NDP Neighbour Advertisement (NA) message
  * @c:		Execution context
+ * @qpair:	Queue pair on which to send the NA
  * @dst:	IPv6 address to send the NA to
  * @addr:	IPv6 address to advertise
  */
-static void ndp_na(const struct ctx *c, const struct in6_addr *dst,
-	    const struct in6_addr *addr)
+static void ndp_na(const struct ctx *c, unsigned int qpair,
+		   const struct in6_addr *dst, const struct in6_addr *addr)
 {
 	union inany_addr tgt;
 	struct ndp_na na = {
@@ -217,7 +219,7 @@ static void ndp_na(const struct ctx *c, const struct in6_addr *dst,
 	inany_from_af(&tgt, AF_INET6, addr);
 	fwd_neigh_mac_get(c, &tgt, na.target_l2_addr.mac);
 
-	ndp_send(c, dst, &na, sizeof(na));
+	ndp_send(c, qpair, dst, &na, sizeof(na));
 }
 
 /**
@@ -228,15 +230,17 @@ static void ndp_na(const struct ctx *c, const struct in6_addr *dst,
 void ndp_unsolicited_na(const struct ctx *c, const struct in6_addr *addr)
 {
 	if (tap_is_ready(c))
-		ndp_na(c, &in6addr_ll_all_nodes, addr);
+		ndp_na(c, QPAIR_DEFAULT, &in6addr_ll_all_nodes, addr);
 }
 
 /**
  * ndp_ra() - Send an NDP Router Advertisement (RA) message
  * @c:		Execution context
+ * @qpair:	Queue pair on which to send the RA
  * @dst:	IPv6 address to send the RA to
  */
-static void ndp_ra(const struct ctx *c, const struct in6_addr *dst)
+static void ndp_ra(const struct ctx *c, unsigned int qpair,
+		   const struct in6_addr *dst)
 {
 	struct ndp_ra ra = {
 		.ih = {
@@ -344,18 +348,19 @@ static void ndp_ra(const struct ctx *c, const struct in6_addr *dst)
 	memcpy(&ra.source_ll.mac, c->our_tap_mac, ETH_ALEN);
 
 	/* NOLINTNEXTLINE(clang-analyzer-security.PointerSub) */
-	ndp_send(c, dst, &ra, ptr - (unsigned char *)&ra);
+	ndp_send(c, qpair, dst, &ra, ptr - (unsigned char *)&ra);
 }
 
 /**
  * ndp() - Check for NDP solicitations, reply as needed
  * @c:		Execution context
+ * @qpair:	Queue pair on which to send replies
  * @saddr:	Source IPv6 address
  * @data:	Single packet with ICMPv6 header
  *
  * Return: 0 if not handled here, 1 if handled, -1 on failure
  */
-int ndp(const struct ctx *c, const struct in6_addr *saddr,
+int ndp(const struct ctx *c, unsigned int qpair, const struct in6_addr *saddr,
 	struct iov_tail *data)
 {
 	struct icmp6hdr ih_storage;
@@ -384,13 +389,13 @@ int ndp(const struct ctx *c, const struct in6_addr *saddr,
 
 		info("NDP: received NS, sending NA");
 
-		ndp_na(c, saddr, &ns->target_addr);
+		ndp_na(c, qpair, saddr, &ns->target_addr);
 	} else if (ih->icmp6_type == RS) {
 		if (c->no_ra)
 			return 1;
 
 		info("NDP: received RS, sending RA");
-		ndp_ra(c, saddr);
+		ndp_ra(c, qpair, saddr);
 	}
 
 	return 1;
@@ -448,7 +453,7 @@ void ndp_timer(const struct ctx *c, const struct timespec *now)
 
 	info("NDP: sending unsolicited RA, next in %llds", (long long)interval);
 
-	ndp_ra(c, &in6addr_ll_all_nodes);
+	ndp_ra(c, QPAIR_DEFAULT, &in6addr_ll_all_nodes);
 
 first:
 	next_ra = now->tv_sec + interval;
@@ -471,5 +476,5 @@ void ndp_send_init_req(const struct ctx *c)
 		.target_addr = c->ip6.addr
 	};
 	debug("Sending initial NDP NS request for guest MAC address");
-	ndp_send(c, &c->ip6.addr, &ns, sizeof(ns));
+	ndp_send(c, QPAIR_DEFAULT, &c->ip6.addr, &ns, sizeof(ns));
 }
diff --git a/ndp.h b/ndp.h
index 56b756d8400b..d33f08d4b802 100644
--- a/ndp.h
+++ b/ndp.h
@@ -8,7 +8,7 @@
 
 struct icmp6hdr;
 
-int ndp(const struct ctx *c, const struct in6_addr *saddr,
+int ndp(const struct ctx *c, unsigned int qpair, const struct in6_addr *saddr,
 	struct iov_tail *data);
 void ndp_timer(const struct ctx *c, const struct timespec *now);
 void ndp_send_init_req(const struct ctx *c);
diff --git a/tap.c b/tap.c
index 8bd1db427721..029888e32db5 100644
--- a/tap.c
+++ b/tap.c
@@ -1029,7 +1029,7 @@ resume:
 				continue;
 
 			ndp_data = data;
-			if (ndp(c, saddr, &ndp_data))
+			if (ndp(c, qpair, saddr, &ndp_data))
 				continue;
 
 			tap_packet_debug(NULL, ip6h, NULL, proto, NULL, 1);
-- 
2.54.0