nss-packages-LiBwrt/qca-nss-clients/patches-11.4/0027-map-t-backport-12.5.patch

--- a/map/map-t/nss_connmgr_map_t.c
+++ b/map/map-t/nss_connmgr_map_t.c
@@ -531,7 +531,7 @@ static void nss_connmgr_map_t_decap_exce
 /*
  * nss_connmgr_map_t_encap_exception()
  *	Exception handler registered to NSS for handling map_t ipv4 pkts
- * Translates ipv4 packet back to ipv6 and send to nat46 device directly.
+ * Send the translated ipv4 packets to the stack directly.
  */
 static void nss_connmgr_map_t_encap_exception(struct net_device *dev,
 			struct sk_buff *skb,
@@ -539,23 +539,7 @@ static void nss_connmgr_map_t_encap_exce
 
 {
 	struct iphdr *ip4_hdr;
-	struct ipv6hdr *ip6_hdr;
-	uint8_t v6saddr[16], v6daddr[16];
-	struct tcphdr *tcph = NULL;
-	struct udphdr *udph = NULL;
-	struct iphdr ip4_hdr_r;
-	__be16 sport, dport;
-	uint8_t nexthdr, hop_limit, tos;
-	int payload_len;
-	bool df_bit = false;
-	uint16_t append_hdr_sz = 0;
-	uint16_t identifier;
-	uint32_t l4_csum, orig_csum;
-	uint16_t csum;
 
-	/*
-	 * Discard L2 header.
-	 */
 	skb_pull(skb, sizeof(struct ethhdr));
 	skb_reset_mac_header(skb);
 	skb_reset_network_header(skb);
@@ -563,123 +547,24 @@ static void nss_connmgr_map_t_encap_exce
 	ip4_hdr = ip_hdr(skb);
 	skb_set_transport_header(skb, ip4_hdr->ihl * 4);
 
-	if (ip4_hdr->protocol == IPPROTO_TCP) {
-		tcph = tcp_hdr(skb);
-		l4_csum = tcph->check;
-		sport = tcph->source;
-		dport = tcph->dest;
-	} else if (ip4_hdr->protocol == IPPROTO_UDP) {
-		udph = udp_hdr(skb);
-		orig_csum = l4_csum = udph->check;
-		sport = udph->source;
-		dport = udph->dest;
-	} else {
-		nss_connmgr_map_t_warning("%px: Unsupported protocol, free it up\n", dev);
-		dev_kfree_skb_any(skb);
-		return;
-	}
-
-	/*
-	 * Undo the checksum of the IPv4 source and destinationIPv4 address.
-	 */
-	csum = ip_compute_csum(&ip4_hdr->saddr, 2 * sizeof(ip4_hdr->saddr));
-	l4_csum += ((~csum) & 0xFFFF);
-
-	/*`
-	 * IPv6 packet is xlated to ipv4 packet by acceleration engine. But there is no ipv4 rule.
-	 * Call xlate_4_to_6() [ which is exported by nat46.ko ] to find original ipv6 src and ipv6 dest address.
-	 * These functions is designed for packets from lan to wan. Since this packet is from wan, need to call
-	 * this function with parameters reversed. ipv4_hdr_r is used for reversing ip addresses.
-	 */
-	ip4_hdr_r.daddr = ip4_hdr->saddr;
-	ip4_hdr_r.saddr = ip4_hdr->daddr;
-
-	if (unlikely(!xlate_4_to_6(dev, &ip4_hdr_r, dport, sport, v6saddr, v6daddr))) { /* exception happened after packet got xlated */
-		nss_connmgr_map_t_warning("%px: Martian ipv4 packet !!..free it. (saddr = 0x%x daddr = 0x%x sport = %d dport = %d)\n", dev,\
-					  ip4_hdr->saddr, ip4_hdr->daddr, sport, dport);
-		dev_kfree_skb_any(skb);
-		return;
-	}
-
-	nexthdr = ip4_hdr->protocol;
-	payload_len = ntohs(ip4_hdr->tot_len) - sizeof(struct iphdr);
-	hop_limit = ip4_hdr->ttl;
-	tos = ip4_hdr->tos;
-	identifier = ntohs(ip4_hdr->id);
-
-	if (ip4_hdr->frag_off & htons(IP_DF)) {
-		df_bit = true;
-	}  else if (map_t_flags & MAPT_FLAG_ADD_DUMMY_HDR) {
-		append_hdr_sz = sizeof(struct frag_hdr);
-	}
-
-	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + append_hdr_sz - sizeof(struct iphdr))) {
-		nss_connmgr_map_t_warning("%px: Not enough headroom for ipv6 packet...Freeing the packet\n", dev);
-		dev_kfree_skb_any(skb);
-		return;
-	}
-
-	skb_push(skb, sizeof(struct ipv6hdr) + append_hdr_sz - sizeof(struct iphdr));
-	skb_reset_network_header(skb);
-	skb_reset_mac_header(skb);
-
-	skb->protocol = htons(ETH_P_IPV6);
-
-	ip6_hdr = ipv6_hdr(skb);
-	memset(ip6_hdr, 0, sizeof(struct ipv6hdr));
-
-	ip6_hdr->version = 6;
-	ip6_hdr->payload_len = htons(payload_len + append_hdr_sz);
-	ip6_hdr->hop_limit = hop_limit;
-
-	nss_connmgr_map_t_ipv6_set_tclass(ip6_hdr, tos);
-	memcpy(&ip6_hdr->daddr, v6saddr, sizeof(struct in6_addr));
-	memcpy(&ip6_hdr->saddr, v6daddr, sizeof(struct in6_addr));
-
-	if (unlikely(df_bit) || !(map_t_flags & MAPT_FLAG_ADD_DUMMY_HDR))  {
-		ip6_hdr->nexthdr = nexthdr;
-	} else {
-		struct frag_hdr tmp_fh, *fh;
-		const __be32 *fh_addr = skb_header_pointer(skb, sizeof(struct ipv6hdr), sizeof(struct frag_hdr), &tmp_fh);
-		if (!fh_addr) {
-			nss_connmgr_map_t_warning("%px: Not able to offset to frag header\n", dev);
-			dev_kfree_skb_any(skb);
-			return;
-		}
-		fh = (struct frag_hdr *)fh_addr;
-		memset(fh, 0, sizeof(struct frag_hdr));
-		fh->identification = htonl(identifier);
-		fh->nexthdr = nexthdr;
-		ip6_hdr->nexthdr = NEXTHDR_FRAGMENT;
-	}
-
-	skb_set_transport_header(skb, sizeof(struct ipv6hdr) + append_hdr_sz);
-
 	/*
-	 * Add the checksum of the IPv6 source and destination address.
+	 * IP Header checksum is not generated yet, calculate it now.
 	 */
-	l4_csum += ip_compute_csum(ip6_hdr->saddr.s6_addr16, 2 * sizeof(ip6_hdr->saddr));
-	/*
-	 * Fold the 32 bits checksum to 16 bits
-	 */
-	l4_csum = (l4_csum & 0x0000FFFF) + (l4_csum >> 16);
-	l4_csum = (l4_csum & 0x0000FFFF) + (l4_csum >> 16);
-
-	if (nexthdr == IPPROTO_TCP) {
-		tcph->check = (uint16_t)l4_csum;
-	} else {
-		udph->check = (orig_csum == 0)? 0:(uint16_t)l4_csum;
-	}
+	ip4_hdr->check = 0;
+	ip4_hdr->check = ip_fast_csum((unsigned char *)ip4_hdr, ip4_hdr->ihl);
 
+	skb->protocol = htons(ETH_P_IP);
 	skb->pkt_type = PACKET_HOST;
 	skb->skb_iif = dev->ifindex;
 	skb->ip_summed = CHECKSUM_NONE;
 	skb->dev = dev;
 
-	nss_connmgr_map_t_trace("%p: ipv4 packet exceptioned after v6 ---> v4 xlate, created original ipv6 packet\n", dev);
-	nss_connmgr_map_t_trace("%p: Calculted ipv6 params: src_addr=%pI6, dest_addr=%pI6, payload_len=%d, checksum=%x\n", dev, v6saddr, v6daddr, payload_len, l4_csum);
-
-	dev_queue_xmit(skb);
+	nss_connmgr_map_t_trace("%px: ipv4 packet exceptioned after v6/v4xlat src=%pI4 dest=%pI4 proto=%d\n",
+			dev, &ip4_hdr->saddr, &ip4_hdr->daddr, ip4_hdr->protocol);
+	/*
+	 * Go through Linux network stack.
+	 */
+	netif_receive_skb(skb);
 	return;
 }