From c724cf99f4d40a056dc1aaef594c55754b43e99a Mon Sep 17 00:00:00 2001
From: Robert Lubos <robert.lubos@nordicsemi.no>
Date: Wed, 8 Nov 2023 10:18:01 +0100
Subject: [PATCH] net: pkt: Add explicit flag to indicate packet is IP
 reassembled

The current logic to determine whether a packet is IP reassembled is
flawed, as it only worked in certain conditions (which was ok, as the
conditions were satisfied for the current use case, but now it's a
public function). Therefore, add an explicit flag that indicates whether
a packet is IP reassembled or not.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
---
 include/zephyr/net/net_pkt.h  | 33 ++++++++++++++++++++++++---------
 subsys/net/ip/ipv4_fragment.c |  1 +
 subsys/net/ip/ipv6_fragment.c |  1 +
 subsys/net/ip/net_pkt.c       |  1 +
 4 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/include/zephyr/net/net_pkt.h b/include/zephyr/net/net_pkt.h
index 591002a9d6..fb00d7b980 100644
--- a/include/zephyr/net/net_pkt.h
+++ b/include/zephyr/net/net_pkt.h
@@ -197,7 +197,9 @@ struct net_pkt {
 	uint8_t chksum_done : 1; /* Checksum has already been computed for
 				  * the packet.
 				  */
-
+#if defined(CONFIG_NET_IPV4_FRAGMENT) || defined(CONFIG_NET_IPV6_FRAGMENT)
+	uint8_t ip_reassembled : 1; /* Packet is a reassembled IP packet. */
+#endif
 	/* bitfield byte alignment boundary */
 
 #if defined(CONFIG_NET_IP)
@@ -836,20 +838,33 @@ static inline void net_pkt_set_ipv6_fragment_id(struct net_pkt *pkt,
 }
 #endif /* CONFIG_NET_IPV6_FRAGMENT */
 
+#if defined(CONFIG_NET_IPV4_FRAGMENT) || defined(CONFIG_NET_IPV6_FRAGMENT)
 static inline bool net_pkt_is_ip_reassembled(struct net_pkt *pkt)
 {
-	if ((IS_ENABLED(CONFIG_NET_IPV4_FRAGMENT) &&
-	     net_pkt_family(pkt) == AF_INET &&
-	     net_pkt_ipv4_fragment_more(pkt)) ||
-	    (IS_ENABLED(CONFIG_NET_IPV6_FRAGMENT) &&
-	     net_pkt_family(pkt) == AF_INET6 &&
-	     net_pkt_ipv6_fragment_start(pkt))) {
-		return true;
-	}
+	return !!(pkt->ip_reassembled);
+}
+
+static inline void net_pkt_set_ip_reassembled(struct net_pkt *pkt,
+					      bool reassembled)
+{
+	pkt->ip_reassembled = reassembled;
+}
+#else /* CONFIG_NET_IPV4_FRAGMENT || CONFIG_NET_IPV6_FRAGMENT */
+static inline bool net_pkt_is_ip_reassembled(struct net_pkt *pkt)
+{
+	ARG_UNUSED(pkt);
 
 	return false;
 }
 
+static inline void net_pkt_set_ip_reassembled(struct net_pkt *pkt,
+					      bool reassembled)
+{
+	ARG_UNUSED(pkt);
+	ARG_UNUSED(reassembled);
+}
+#endif /* CONFIG_NET_IPV4_FRAGMENT || CONFIG_NET_IPV6_FRAGMENT */
+
 static inline uint8_t net_pkt_priority(struct net_pkt *pkt)
 {
 	return pkt->priority;
diff --git a/subsys/net/ip/ipv4_fragment.c b/subsys/net/ip/ipv4_fragment.c
index 5bcf4e0026..ee6e43c83d 100644
--- a/subsys/net/ip/ipv4_fragment.c
+++ b/subsys/net/ip/ipv4_fragment.c
@@ -203,6 +203,7 @@ static void reassemble_packet(struct net_ipv4_reassembly *reass)
 	ipv4_hdr->chksum = net_calc_chksum_ipv4(pkt);
 
 	net_pkt_set_data(pkt, &ipv4_access);
+	net_pkt_set_ip_reassembled(pkt, true);
 
 	LOG_DBG("New pkt %p IPv4 len is %d bytes", pkt, net_pkt_get_len(pkt));
 
diff --git a/subsys/net/ip/ipv6_fragment.c b/subsys/net/ip/ipv6_fragment.c
index 6d391b3b82..fda00c59f0 100644
--- a/subsys/net/ip/ipv6_fragment.c
+++ b/subsys/net/ip/ipv6_fragment.c
@@ -338,6 +338,7 @@ static void reassemble_packet(struct net_ipv6_reassembly *reass)
 	ipv6.hdr->len = htons(len);
 
 	net_pkt_set_data(pkt, &ipv6_access);
+	net_pkt_set_ip_reassembled(pkt, true);
 
 	NET_DBG("New pkt %p IPv6 len is %d bytes", pkt,
 		len + NET_IPV6H_LEN);
diff --git a/subsys/net/ip/net_pkt.c b/subsys/net/ip/net_pkt.c
index cef7cbcd10..ea60060abe 100644
--- a/subsys/net/ip/net_pkt.c
+++ b/subsys/net/ip/net_pkt.c
@@ -1813,6 +1813,7 @@ static void clone_pkt_attributes(struct net_pkt *pkt, struct net_pkt *clone_pkt)
 	net_pkt_set_ptp(clone_pkt, net_pkt_is_ptp(pkt));
 	net_pkt_set_forwarding(clone_pkt, net_pkt_forwarding(pkt));
 	net_pkt_set_chksum_done(clone_pkt, net_pkt_is_chksum_done(pkt));
+	net_pkt_set_ip_reassembled(pkt, net_pkt_is_ip_reassembled(pkt));
 
 	net_pkt_set_l2_bridged(clone_pkt, net_pkt_is_l2_bridged(pkt));
 	net_pkt_set_l2_processed(clone_pkt, net_pkt_is_l2_processed(pkt));