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 * Forward all aggregated SKBs held by lro_mgr to network stack
138 */
139
140void lro_flush_all(struct net_lro_mgr *lro_mgr);
141
142#endif
143