include/linux/inet_lro.h

   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
  38 struct 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  */
  47 struct 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
  74 struct 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
 133 void 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
 152 void 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
 160 void lro_flush_all(struct net_lro_mgr *lro_mgr);
 161
 162 void lro_flush_pkt(struct net_lro_mgr *lro_mgr,
 163                    struct iphdr *iph, struct tcphdr *tcph);
 164
 165 #endif