/*
   *  linux/include/linux/inet_lro.h
   *
   *  Large Receive Offload (ipv4 / tcp)
   *
   *  (C) Copyright IBM Corp. 2007
   *
   *  Authors:
   *       Jan-Bernd Themann <themann@de.ibm.com>
   *       Christoph Raisch <raisch@de.ibm.com>
   *
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2, or (at your option)
   * any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #ifndef __INET_LRO_H_
  #define __INET_LRO_H_
  
  #include <net/ip.h>
  #include <net/tcp.h>
  
  /*
   * LRO statistics
   */
  
  struct net_lro_stats {
  	unsigned long aggregated;
  	unsigned long flushed;
  	unsigned long no_desc;
  };
  
  /*
   * LRO descriptor for a tcp session
   */
  struct net_lro_desc {
  	struct sk_buff *parent;
  	struct sk_buff *last_skb;
  	struct skb_frag_struct *next_frag;
  	struct iphdr *iph;
  	struct tcphdr *tcph;

  	__wsum  data_csum;

  	__be32 tcp_rcv_tsecr;
  	__be32 tcp_rcv_tsval;

  	__be32 tcp_ack;

  	u32 tcp_next_seq;
  	u32 skb_tot_frags_len;
  	u16 ip_tot_len;
  	u16 tcp_saw_tstamp; 		/* timestamps enabled */

  	__be16 tcp_window;

  	int pkt_aggr_cnt;		/* counts aggregated packets */
  	int vlan_packet;
  	int mss;
  	int active;
  };
  
  /*
   * Large Receive Offload (LRO) Manager
   *
   * Fields must be set by driver
   */
  
  struct net_lro_mgr {
  	struct net_device *dev;
  	struct net_lro_stats stats;
  
  	/* LRO features */
  	unsigned long features;
  #define LRO_F_NAPI            1  /* Pass packets to stack via NAPI */
  #define LRO_F_EXTRACT_VLAN_ID 2  /* Set flag if VLAN IDs are extracted
  				    from received packets and eth protocol
  				    is still ETH_P_8021Q */

  	/*
  	 * Set for generated SKBs that are not added to
  	 * the frag list in fragmented mode
  	 */
  	u32 ip_summed;

  	u32 ip_summed_aggr; /* Set in aggregated SKBs: CHECKSUM_UNNECESSARY
  			     * or CHECKSUM_NONE */
  
  	int max_desc; /* Max number of LRO descriptors  */
  	int max_aggr; /* Max number of LRO packets to be aggregated */

  	int frag_align_pad; /* Padding required to properly align layer 3
  			     * headers in generated skb when using frags */

  	struct net_lro_desc *lro_arr; /* Array of LRO descriptors */
  
  	/*
  	 * Optimized driver functions
  	 *
  	 * get_skb_header: returns tcp and ip header for packet in SKB
  	 */
  	int (*get_skb_header)(struct sk_buff *skb, void **ip_hdr,
  			      void **tcpudp_hdr, u64 *hdr_flags, void *priv);
  
  	/* hdr_flags: */
  #define LRO_IPV4 1 /* ip_hdr is IPv4 header */
  #define LRO_TCP  2 /* tcpudp_hdr is TCP header */
  
  	/*
  	 * get_frag_header: returns mac, tcp and ip header for packet in SKB
  	 *
  	 * @hdr_flags: Indicate what kind of LRO has to be done
  	 *             (IPv4/IPv6/TCP/UDP)
  	 */
  	int (*get_frag_header)(struct skb_frag_struct *frag, void **mac_hdr,
  			       void **ip_hdr, void **tcpudp_hdr, u64 *hdr_flags,
  			       void *priv);
  };
  
  /*
   * Processes a SKB
   *
   * @lro_mgr: LRO manager to use
   * @skb: SKB to aggregate
   * @priv: Private data that may be used by driver functions
   *        (for example get_tcp_ip_hdr)
   */
  
  void lro_receive_skb(struct net_lro_mgr *lro_mgr,
  		     struct sk_buff *skb,
  		     void *priv);

  /*
   * Forward all aggregated SKBs held by lro_mgr to network stack
   */
  
  void lro_flush_all(struct net_lro_mgr *lro_mgr);

  #endif