linux/include/linux/inet_lro.h
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   1/*
   2 *  linux/include/linux/inet_lro.h
   3 *
   4 *  Large Receive Offload (ipv4 / tcp)
   5 *
   6 *  (C) Copyright IBM Corp. 2007
   7 *
   8 *  Authors:
   9 *       Jan-Bernd Themann <themann@de.ibm.com>
  10 *       Christoph Raisch <raisch@de.ibm.com>
  11 *
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2, or (at your option)
  16 * any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program; if not, write to the Free Software
  25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26 */
  27
  28#ifndef __INET_LRO_H_
  29#define __INET_LRO_H_
  30
  31#include <net/ip.h>
  32#include <net/tcp.h>
  33
  34/*
  35 * LRO statistics
  36 */
  37
  38struct net_lro_stats {
  39        unsigned long aggregated;
  40        unsigned long flushed;
  41        unsigned long no_desc;
  42};
  43
  44/*
  45 * LRO descriptor for a tcp session
  46 */
  47struct net_lro_desc {
  48        struct sk_buff *parent;
  49        struct sk_buff *last_skb;
  50        struct skb_frag_struct *next_frag;
  51        struct iphdr *iph;
  52        struct tcphdr *tcph;
  53        __wsum  data_csum;
  54        __be32 tcp_rcv_tsecr;
  55        __be32 tcp_rcv_tsval;
  56        __be32 tcp_ack;
  57        u32 tcp_next_seq;
  58        u32 skb_tot_frags_len;
  59        u16 ip_tot_len;
  60        u16 tcp_saw_tstamp;             /* timestamps enabled */
  61        __be16 tcp_window;
  62        int pkt_aggr_cnt;               /* counts aggregated packets */
  63        int vlan_packet;
  64        int mss;
  65        int active;
  66};
  67
  68/*
  69 * Large Receive Offload (LRO) Manager
  70 *
  71 * Fields must be set by driver
  72 */
  73
  74struct net_lro_mgr {
  75        struct net_device *dev;
  76        struct net_lro_stats stats;
  77
  78        /* LRO features */
  79        unsigned long features;
  80#define LRO_F_NAPI            1  /* Pass packets to stack via NAPI */
  81#define LRO_F_EXTRACT_VLAN_ID 2  /* Set flag if VLAN IDs are extracted
  82                                    from received packets and eth protocol
  83                                    is still ETH_P_8021Q */
  84
  85        /*
  86         * Set for generated SKBs that are not added to
  87         * the frag list in fragmented mode
  88         */
  89        u32 ip_summed;
  90        u32 ip_summed_aggr; /* Set in aggregated SKBs: CHECKSUM_UNNECESSARY
  91                             * or CHECKSUM_NONE */
  92
  93        int max_desc; /* Max number of LRO descriptors  */
  94        int max_aggr; /* Max number of LRO packets to be aggregated */
  95
  96        int frag_align_pad; /* Padding required to properly align layer 3
  97                             * headers in generated skb when using frags */
  98
  99        struct net_lro_desc *lro_arr; /* Array of LRO descriptors */
 100
 101        /*
 102         * Optimized driver functions
 103         *
 104         * get_skb_header: returns tcp and ip header for packet in SKB
 105         */
 106        int (*get_skb_header)(struct sk_buff *skb, void **ip_hdr,
 107                              void **tcpudp_hdr, u64 *hdr_flags, void *priv);
 108
 109        /* hdr_flags: */
 110#define LRO_IPV4 1 /* ip_hdr is IPv4 header */
 111#define LRO_TCP  2 /* tcpudp_hdr is TCP header */
 112
 113        /*
 114         * get_frag_header: returns mac, tcp and ip header for packet in SKB
 115         *
 116         * @hdr_flags: Indicate what kind of LRO has to be done
 117         *             (IPv4/IPv6/TCP/UDP)
 118         */
 119        int (*get_frag_header)(struct skb_frag_struct *frag, void **mac_hdr,
 120                               void **ip_hdr, void **tcpudp_hdr, u64 *hdr_flags,
 121                               void *priv);
 122};
 123
 124/*
 125 * Processes a SKB
 126 *
 127 * @lro_mgr: LRO manager to use
 128 * @skb: SKB to aggregate
 129 * @priv: Private data that may be used by driver functions
 130 *        (for example get_tcp_ip_hdr)
 131 */
 132
 133void lro_receive_skb(struct net_lro_mgr *lro_mgr,
 134                     struct sk_buff *skb,
 135                     void *priv);
 136
 137/*
 138 * Processes a fragment list
 139 *
 140 * This functions aggregate fragments and generate SKBs do pass
 141 * the packets to the stack.
 142 *
 143 * @lro_mgr: LRO manager to use
 144 * @frags: Fragment to be processed. Must contain entire header in first
 145 *         element.
 146 * @len: Length of received data
 147 * @true_size: Actual size of memory the fragment is consuming
 148 * @priv: Private data that may be used by driver functions
 149 *        (for example get_tcp_ip_hdr)
 150 */
 151
 152void lro_receive_frags(struct net_lro_mgr *lro_mgr,
 153                       struct skb_frag_struct *frags,
 154                       int len, int true_size, void *priv, __wsum sum);
 155
 156/*
 157 * Forward all aggregated SKBs held by lro_mgr to network stack
 158 */
 159
 160void lro_flush_all(struct net_lro_mgr *lro_mgr);
 161
 162void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
 163                   struct iphdr *iph, struct tcphdr *tcph);
 164
 165#endif
 166
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