Start process of removing the use of the deprecated "M_FLOWID" flag

from the FreeBSD network code. The flag is still kept around in the
"sys/mbuf.h" header file, but does no longer have any users. Instead
the "m_pkthdr.rsstype" field in the mbuf structure is now used to
decide the meaning of the "m_pkthdr.flowid" field. To modify the
"m_pkthdr.rsstype" field please use the existing "M_HASHTYPE_XXX"
macros as defined in the "sys/mbuf.h" header file.

This patch introduces new behaviour in the transmit direction.
Previously network drivers checked if "M_FLOWID" was set in "m_flags"
before using the "m_pkthdr.flowid" field. This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from
"M_HASHTYPE_NONE". In the future more hashtypes will be added, for
example hashtypes for hardware dedicated flows.

"M_HASHTYPE_OPAQUE" indicates that the "m_pkthdr.flowid" value is
valid and has no particular type. This change removes the need for an
"if" statement in TCP transmit code checking for the presence of a
valid flowid value. The "if" statement mentioned above is now a direct
variable assignment which is then later checked by the respective
network drivers like before.

Additional notes:
- The SCTP code changes will be committed as a separate patch.
- Removal of the "M_FLOWID" flag will also be done separately.
- The FreeBSD version has been bumped.

MFC after:	1 month
Sponsored by:	Mellanox Technologies

6 files changed, 14 insertions, 10 deletions

diff --git a/sys/net/flowtable.c b/sys/net/flowtable.c
index fe6a52c..0d584fe 100644
--- a/sys/net/flowtable.c
+++ b/sys/net/flowtable.c
@@ -688,8 +688,8 @@ flowtable_lookup(sa_family_t sa, struct mbuf *m, struct route *ro)
 	if (fle == NULL)
 		return (EHOSTUNREACH);
 
-	if (!(m->m_flags & M_FLOWID)) {
-		m->m_flags |= M_FLOWID;
+	if (M_HASHTYPE_GET(m) == M_HASHTYPE_NONE) {
+		M_HASHTYPE_SET(m, M_HASHTYPE_OPAQUE);
 		m->m_pkthdr.flowid = fle->f_hash;
 	}
 
diff --git a/sys/net/ieee8023ad_lacp.c b/sys/net/ieee8023ad_lacp.c
index 106df68..75f6366 100644
--- a/sys/net/ieee8023ad_lacp.c
+++ b/sys/net/ieee8023ad_lacp.c
@@ -835,7 +835,8 @@ lacp_select_tx_port(struct lagg_softc *sc, struct mbuf *m)
 		return (NULL);
 	}
 
-	if ((sc->sc_opts & LAGG_OPT_USE_FLOWID) && (m->m_flags & M_FLOWID))
+	if ((sc->sc_opts & LAGG_OPT_USE_FLOWID) &&
+	    M_HASHTYPE_GET(m) != M_HASHTYPE_NONE)
 		hash = m->m_pkthdr.flowid >> sc->flowid_shift;
 	else
 		hash = lagg_hashmbuf(sc, m, lsc->lsc_hashkey);
diff --git a/sys/net/if_lagg.c b/sys/net/if_lagg.c
index 5c8b2e1..45315b6 100644
--- a/sys/net/if_lagg.c
+++ b/sys/net/if_lagg.c
@@ -247,14 +247,14 @@ SYSCTL_INT(_net_link_lagg, OID_AUTO, failover_rx_all, CTLFLAG_RW | CTLFLAG_VNET,
     &VNET_NAME(lagg_failover_rx_all), 0,
     "Accept input from any interface in a failover lagg");
 
-/* Default value for using M_FLOWID */
+/* Default value for using flowid */
 static VNET_DEFINE(int, def_use_flowid) = 1;
 #define	V_def_use_flowid	VNET(def_use_flowid)
 SYSCTL_INT(_net_link_lagg, OID_AUTO, default_use_flowid, CTLFLAG_RWTUN,
     &VNET_NAME(def_use_flowid), 0,
     "Default setting for using flow id for load sharing");
 
-/* Default value for using M_FLOWID */
+/* Default value for flowid shift */
 static VNET_DEFINE(int, def_flowid_shift) = 16;
 #define	V_def_flowid_shift	VNET(def_flowid_shift)
 SYSCTL_INT(_net_link_lagg, OID_AUTO, default_flowid_shift, CTLFLAG_RWTUN,
@@ -2148,7 +2148,8 @@ lagg_lb_start(struct lagg_softc *sc, struct mbuf *m)
 	struct lagg_port *lp = NULL;
 	uint32_t p = 0;
 
-	if ((sc->sc_opts & LAGG_OPT_USE_FLOWID) && (m->m_flags & M_FLOWID))
+	if ((sc->sc_opts & LAGG_OPT_USE_FLOWID) &&
+	    M_HASHTYPE_GET(m) != M_HASHTYPE_NONE)
 		p = m->m_pkthdr.flowid >> sc->flowid_shift;
 	else
 		p = lagg_hashmbuf(sc, m, lb->lb_key);
diff --git a/sys/net/if_lagg.h b/sys/net/if_lagg.h
index e86ed06..8d6decd 100644
--- a/sys/net/if_lagg.h
+++ b/sys/net/if_lagg.h
@@ -143,9 +143,9 @@ struct lagg_reqopts {
 
 	int			ro_opts;		/* Option bitmap */
 #define	LAGG_OPT_NONE			0x00
-#define	LAGG_OPT_USE_FLOWID		0x01		/* use M_FLOWID */
+#define	LAGG_OPT_USE_FLOWID		0x01		/* enable use of flowid */
 /* Pseudo flags which are used in ro_opts but not stored into sc_opts. */
-#define	LAGG_OPT_FLOWIDSHIFT		0x02		/* Set flowid */
+#define	LAGG_OPT_FLOWIDSHIFT		0x02		/* set flowid shift */
 #define	LAGG_OPT_FLOWIDSHIFT_MASK	0x1f		/* flowid is uint32_t */
 #define	LAGG_OPT_LACP_STRICT		0x10		/* LACP strict mode */
 #define	LAGG_OPT_LACP_TXTEST		0x20		/* LACP debug: txtest */
diff --git a/sys/net/if_vxlan.c b/sys/net/if_vxlan.c
index 5badf00..59c76eb 100644
--- a/sys/net/if_vxlan.c
+++ b/sys/net/if_vxlan.c
@@ -2236,6 +2236,7 @@ vxlan_pick_source_port(struct vxlan_softc *sc, struct mbuf *m)
 
 	range = sc->vxl_max_port - sc->vxl_min_port + 1;
 
+	/* check if flowid is set and not opaque */
 	if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE &&
 	    M_HASHTYPE_GET(m) != M_HASHTYPE_OPAQUE)
 		hash = m->m_pkthdr.flowid;
diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index 049bbf1..178c3cb 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -682,12 +682,13 @@ netisr_select_cpuid(struct netisr_proto *npp, u_int dispatch_policy,
 	}
 
 	if (policy == NETISR_POLICY_FLOW) {
-		if (!(m->m_flags & M_FLOWID) && npp->np_m2flow != NULL) {
+		if (M_HASHTYPE_GET(m) == M_HASHTYPE_NONE &&
+		    npp->np_m2flow != NULL) {
 			m = npp->np_m2flow(m, source);
 			if (m == NULL)
 				return (NULL);
 		}
-		if (m->m_flags & M_FLOWID) {
+		if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
 			*cpuidp =
 			    netisr_default_flow2cpu(m->m_pkthdr.flowid);
 			return (m);