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From:   Yevhen Orlov <yevhen.orlov@plvision.eu>
To:     netdev@vger.kernel.org
Cc:     Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu>,
        Taras Chornyi <taras.chornyi@plvision.eu>,
        Mickey Rachamim <mickeyr@marvell.com>,
        Serhiy Pshyk <serhiy.pshyk@plvision.eu>,
        Yevhen Orlov <yevhen.orlov@plvision.eu>,
        Taras Chornyi <tchornyi@marvell.com>,
        Oleksandr Mazur <oleksandr.mazur@plvision.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org
Subject: [PATCH net-next 6/9] net: marvell: prestera: Add heplers to interact with fib_notifier_info
Date:   Sun, 10 Jul 2022 20:22:04 +0300
Message-Id: <20220710172208.29851-7-yevhen.orlov@plvision.eu>
In-Reply-To: <20220710172208.29851-1-yevhen.orlov@plvision.eu>
References: <20220710172208.29851-1-yevhen.orlov@plvision.eu>
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This will be used to implement nexthops related logic in next patches.
Also try to keep ipv4/6 abstraction to be able to reuse helpers for ipv6
in the future.

Co-developed-by: Taras Chornyi <tchornyi@marvell.com>
Signed-off-by: Taras Chornyi <tchornyi@marvell.com>
Co-developed-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Yevhen Orlov <yevhen.orlov@plvision.eu>
---
 .../marvell/prestera/prestera_router.c        | 311 ++++++++++++++++--
 1 file changed, 277 insertions(+), 34 deletions(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_router.c b/drivers/net/ethernet/marvell/prestera/prestera_router.c
index db327ab4a072..0150aa33c958 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_router.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_router.c
@@ -7,6 +7,7 @@
 #include <net/inet_dscp.h>
 #include <net/switchdev.h>
 #include <linux/rhashtable.h>
+#include <net/nexthop.h>
 
 #include "prestera.h"
 #include "prestera_router_hw.h"
@@ -26,9 +27,10 @@ struct prestera_kern_fib_cache {
 	} lpm_info; /* hold prepared lpm info */
 	/* Indicate if route is not overlapped by another table */
 	struct rhash_head ht_node; /* node of prestera_router */
-	struct fib_info *fi;
-	dscp_t kern_dscp;
-	u8 kern_type;
+	union {
+		struct fib_notifier_info info; /* point to any of 4/6 */
+		struct fib_entry_notifier_info fen4_info;
+	};
 	bool reachable;
 };
 
@@ -51,15 +53,253 @@ static u32 prestera_fix_tb_id(u32 tb_id)
 }
 
 static void
-prestera_util_fen_info2fib_cache_key(struct fib_entry_notifier_info *fen_info,
+prestera_util_fen_info2fib_cache_key(struct fib_notifier_info *info,
 				     struct prestera_kern_fib_cache_key *key)
 {
+	struct fib_entry_notifier_info *fen_info =
+		container_of(info, struct fib_entry_notifier_info, info);
+
 	memset(key, 0, sizeof(*key));
+	key->addr.v = PRESTERA_IPV4;
 	key->addr.u.ipv4 = cpu_to_be32(fen_info->dst);
 	key->prefix_len = fen_info->dst_len;
 	key->kern_tb_id = fen_info->tb_id;
 }
 
+static bool __prestera_fi_is_direct(struct fib_info *fi)
+{
+	struct fib_nh *fib_nh;
+
+	if (fib_info_num_path(fi) == 1) {
+		fib_nh = fib_info_nh(fi, 0);
+		if (fib_nh->fib_nh_scope == RT_SCOPE_HOST)
+			return true;
+	}
+
+	return false;
+}
+
+static bool prestera_fi_is_direct(struct fib_info *fi)
+{
+	if (fi->fib_type != RTN_UNICAST)
+		return false;
+
+	return __prestera_fi_is_direct(fi);
+}
+
+static bool prestera_fi_is_nh(struct fib_info *fi)
+{
+	if (fi->fib_type != RTN_UNICAST)
+		return false;
+
+	return !__prestera_fi_is_direct(fi);
+}
+
+static bool __prestera_fi6_is_direct(struct fib6_info *fi)
+{
+	if (!fi->fib6_nh->nh_common.nhc_gw_family)
+		return true;
+
+	return false;
+}
+
+static bool prestera_fi6_is_direct(struct fib6_info *fi)
+{
+	if (fi->fib6_type != RTN_UNICAST)
+		return false;
+
+	return __prestera_fi6_is_direct(fi);
+}
+
+static bool prestera_fi6_is_nh(struct fib6_info *fi)
+{
+	if (fi->fib6_type != RTN_UNICAST)
+		return false;
+
+	return !__prestera_fi6_is_direct(fi);
+}
+
+static bool prestera_fib_info_is_direct(struct fib_notifier_info *info)
+{
+	struct fib6_entry_notifier_info *fen6_info =
+		container_of(info, struct fib6_entry_notifier_info, info);
+	struct fib_entry_notifier_info *fen_info =
+		container_of(info, struct fib_entry_notifier_info, info);
+
+	if (info->family == AF_INET)
+		return prestera_fi_is_direct(fen_info->fi);
+	else
+		return prestera_fi6_is_direct(fen6_info->rt);
+}
+
+static bool prestera_fib_info_is_nh(struct fib_notifier_info *info)
+{
+	struct fib6_entry_notifier_info *fen6_info =
+		container_of(info, struct fib6_entry_notifier_info, info);
+	struct fib_entry_notifier_info *fen_info =
+		container_of(info, struct fib_entry_notifier_info, info);
+
+	if (info->family == AF_INET)
+		return prestera_fi_is_nh(fen_info->fi);
+	else
+		return prestera_fi6_is_nh(fen6_info->rt);
+}
+
+/* must be called with rcu_read_lock() */
+static int prestera_util_kern_get_route(struct fib_result *res, u32 tb_id,
+					__be32 *addr)
+{
+	struct fib_table *tb;
+	struct flowi4 fl4;
+	int ret;
+
+	/* TODO: walkthrough appropriate tables in kernel
+	 * to know if the same prefix exists in several tables
+	 */
+	tb = fib_new_table(&init_net, tb_id);
+	if (!tb)
+		return -ENOENT;
+
+	memset(&fl4, 0, sizeof(fl4));
+	fl4.daddr = *addr;
+	ret = fib_table_lookup(tb, &fl4, res, FIB_LOOKUP_NOREF);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static bool
+__prestera_util_kern_n_is_reachable_v4(u32 tb_id, __be32 *addr,
+				       struct net_device *dev)
+{
+	struct fib_nh *fib_nh;
+	struct fib_result res;
+	bool reachable;
+
+	reachable = false;
+
+	if (!prestera_util_kern_get_route(&res, tb_id, addr))
+		if (prestera_fi_is_direct(res.fi)) {
+			fib_nh = fib_info_nh(res.fi, 0);
+			if (dev == fib_nh->fib_nh_dev)
+				reachable = true;
+		}
+
+	return reachable;
+}
+
+/* Check if neigh route is reachable */
+static bool
+prestera_util_kern_n_is_reachable(u32 tb_id,
+				  struct prestera_ip_addr *addr,
+				  struct net_device *dev)
+{
+	if (addr->v == PRESTERA_IPV4)
+		return __prestera_util_kern_n_is_reachable_v4(tb_id,
+							      &addr->u.ipv4,
+							      dev);
+	else
+		return false;
+}
+
+static void prestera_util_kern_set_neigh_offload(struct neighbour *n,
+						 bool offloaded)
+{
+	if (offloaded)
+		n->flags |= NTF_OFFLOADED;
+	else
+		n->flags &= ~NTF_OFFLOADED;
+}
+
+static void
+prestera_util_kern_set_nh_offload(struct fib_nh_common *nhc, bool offloaded, bool trap)
+{
+		if (offloaded)
+			nhc->nhc_flags |= RTNH_F_OFFLOAD;
+		else
+			nhc->nhc_flags &= ~RTNH_F_OFFLOAD;
+
+		if (trap)
+			nhc->nhc_flags |= RTNH_F_TRAP;
+		else
+			nhc->nhc_flags &= ~RTNH_F_TRAP;
+}
+
+static struct fib_nh_common *
+prestera_kern_fib_info_nhc(struct fib_notifier_info *info, int n)
+{
+	struct fib6_entry_notifier_info *fen6_info;
+	struct fib_entry_notifier_info *fen4_info;
+	struct fib6_info *iter;
+
+	if (info->family == AF_INET) {
+		fen4_info = container_of(info, struct fib_entry_notifier_info,
+					 info);
+		return &fib_info_nh(fen4_info->fi, n)->nh_common;
+	} else if (info->family == AF_INET6) {
+		fen6_info = container_of(info, struct fib6_entry_notifier_info,
+					 info);
+		if (!n)
+			return &fen6_info->rt->fib6_nh->nh_common;
+
+		list_for_each_entry(iter, &fen6_info->rt->fib6_siblings,
+				    fib6_siblings) {
+			if (!--n)
+				return &iter->fib6_nh->nh_common;
+		}
+	}
+
+	/* if family is incorrect - than upper functions has BUG */
+	/* if doesn't find requested index - there is alsi bug, because
+	 * valid index must be produced by nhs, which checks list length
+	 */
+	WARN(1, "Invalid parameters passed to %s n=%d i=%p",
+	     __func__, n, info);
+	return NULL;
+}
+
+static int prestera_kern_fib_info_nhs(struct fib_notifier_info *info)
+{
+	struct fib6_entry_notifier_info *fen6_info;
+	struct fib_entry_notifier_info *fen4_info;
+
+	if (info->family == AF_INET) {
+		fen4_info = container_of(info, struct fib_entry_notifier_info,
+					 info);
+		return fib_info_num_path(fen4_info->fi);
+	} else if (info->family == AF_INET6) {
+		fen6_info = container_of(info, struct fib6_entry_notifier_info,
+					 info);
+		return fen6_info->rt->fib6_nh ?
+			(fen6_info->rt->fib6_nsiblings + 1) : 0;
+	}
+
+	return 0;
+}
+
+static unsigned char
+prestera_kern_fib_info_type(struct fib_notifier_info *info)
+{
+	struct fib6_entry_notifier_info *fen6_info;
+	struct fib_entry_notifier_info *fen4_info;
+
+	if (info->family == AF_INET) {
+		fen4_info = container_of(info, struct fib_entry_notifier_info,
+					 info);
+		return fen4_info->fi->fib_type;
+	} else if (info->family == AF_INET6) {
+		fen6_info = container_of(info, struct fib6_entry_notifier_info,
+					 info);
+		/* TODO: ECMP in ipv6 is several routes.
+		 * Every route has single nh.
+		 */
+		return fen6_info->rt->fib6_type;
+	}
+
+	return RTN_UNSPEC;
+}
+
 static struct prestera_kern_fib_cache *
 prestera_kern_fib_cache_find(struct prestera_switch *sw,
 			     struct prestera_kern_fib_cache_key *key)
@@ -76,7 +316,7 @@ static void
 prestera_kern_fib_cache_destroy(struct prestera_switch *sw,
 				struct prestera_kern_fib_cache *fib_cache)
 {
-	fib_info_put(fib_cache->fi);
+	fib_info_put(fib_cache->fen4_info.fi);
 	rhashtable_remove_fast(&sw->router->kern_fib_cache_ht,
 			       &fib_cache->ht_node,
 			       __prestera_kern_fib_cache_ht_params);
@@ -89,8 +329,10 @@ prestera_kern_fib_cache_destroy(struct prestera_switch *sw,
 static struct prestera_kern_fib_cache *
 prestera_kern_fib_cache_create(struct prestera_switch *sw,
 			       struct prestera_kern_fib_cache_key *key,
-			       struct fib_info *fi, dscp_t dscp, u8 type)
+			       struct fib_notifier_info *info)
 {
+	struct fib_entry_notifier_info *fen_info =
+		container_of(info, struct fib_entry_notifier_info, info);
 	struct prestera_kern_fib_cache *fib_cache;
 	int err;
 
@@ -99,10 +341,8 @@ prestera_kern_fib_cache_create(struct prestera_switch *sw,
 		goto err_kzalloc;
 
 	memcpy(&fib_cache->key, key, sizeof(*key));
-	fib_info_hold(fi);
-	fib_cache->fi = fi;
-	fib_cache->kern_dscp = dscp;
-	fib_cache->kern_type = type;
+	fib_info_hold(fen_info->fi);
+	memcpy(&fib_cache->fen4_info, fen_info, sizeof(*fen_info));
 
 	err = rhashtable_insert_fast(&sw->router->kern_fib_cache_ht,
 				     &fib_cache->ht_node,
@@ -113,7 +353,7 @@ prestera_kern_fib_cache_create(struct prestera_switch *sw,
 	return fib_cache;
 
 err_ht_insert:
-	fib_info_put(fi);
+	fib_info_put(fen_info->fi);
 	kfree(fib_cache);
 err_kzalloc:
 	return NULL;
@@ -126,21 +366,25 @@ __prestera_k_arb_fib_lpm_offload_set(struct prestera_switch *sw,
 {
 	struct fib_rt_info fri;
 
-	if (fc->key.addr.v != PRESTERA_IPV4)
+	switch (fc->key.addr.v) {
+	case PRESTERA_IPV4:
+		fri.fi = fc->fen4_info.fi;
+		fri.tb_id = fc->key.kern_tb_id;
+		fri.dst = fc->key.addr.u.ipv4;
+		fri.dst_len = fc->key.prefix_len;
+		fri.dscp = fc->fen4_info.dscp;
+		fri.type = fc->fen4_info.type;
+		/* flags begin */
+		fri.offload = offload;
+		fri.trap = trap;
+		fri.offload_failed = fail;
+		/* flags end */
+		fib_alias_hw_flags_set(&init_net, &fri);
 		return;
-
-	fri.fi = fc->fi;
-	fri.tb_id = fc->key.kern_tb_id;
-	fri.dst = fc->key.addr.u.ipv4;
-	fri.dst_len = fc->key.prefix_len;
-	fri.dscp = fc->kern_dscp;
-	fri.type = fc->kern_type;
-	/* flags begin */
-	fri.offload = offload;
-	fri.trap = trap;
-	fri.offload_failed = fail;
-	/* flags end */
-	fib_alias_hw_flags_set(&init_net, &fri);
+	case PRESTERA_IPV6:
+		/* TODO */
+		return;
+	}
 }
 
 static int
@@ -149,7 +393,7 @@ __prestera_pr_k_arb_fc_lpm_info_calc(struct prestera_switch *sw,
 {
 	memset(&fc->lpm_info, 0, sizeof(fc->lpm_info));
 
-	switch (fc->fi->fib_type) {
+	switch (prestera_kern_fib_info_type(&fc->info)) {
 	case RTN_UNICAST:
 		fc->lpm_info.fib_type = PRESTERA_FIB_TYPE_TRAP;
 		break;
@@ -274,14 +518,14 @@ __prestera_k_arb_util_fib_overlapped(struct prestera_switch *sw,
 static int
 prestera_k_arb_fib_evt(struct prestera_switch *sw,
 		       bool replace, /* replace or del */
-		       struct fib_entry_notifier_info *fen_info)
+		       struct fib_notifier_info *info)
 {
 	struct prestera_kern_fib_cache *tfib_cache, *bfib_cache; /* top/btm */
 	struct prestera_kern_fib_cache_key fc_key;
 	struct prestera_kern_fib_cache *fib_cache;
 	int err;
 
-	prestera_util_fen_info2fib_cache_key(fen_info, &fc_key);
+	prestera_util_fen_info2fib_cache_key(info, &fc_key);
 	fib_cache = prestera_kern_fib_cache_find(sw, &fc_key);
 	if (fib_cache) {
 		fib_cache->reachable = false;
@@ -304,10 +548,7 @@ prestera_k_arb_fib_evt(struct prestera_switch *sw,
 	}
 
 	if (replace) {
-		fib_cache = prestera_kern_fib_cache_create(sw, &fc_key,
-							   fen_info->fi,
-							   fen_info->dscp,
-							   fen_info->type);
+		fib_cache = prestera_kern_fib_cache_create(sw, &fc_key, info);
 		if (!fib_cache) {
 			dev_err(sw->dev->dev, "fib_cache == NULL");
 			return -ENOENT;
@@ -512,13 +753,15 @@ static void __prestera_router_fib_event_work(struct work_struct *work)
 
 	switch (fib_work->event) {
 	case FIB_EVENT_ENTRY_REPLACE:
-		err = prestera_k_arb_fib_evt(sw, true, &fib_work->fen_info);
+		err = prestera_k_arb_fib_evt(sw, true,
+					     &fib_work->fen_info.info);
 		if (err)
 			goto err_out;
 
 		break;
 	case FIB_EVENT_ENTRY_DEL:
-		err = prestera_k_arb_fib_evt(sw, false, &fib_work->fen_info);
+		err = prestera_k_arb_fib_evt(sw, false,
+					     &fib_work->fen_info.info);
 		if (err)
 			goto err_out;
 
-- 
2.17.1